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1
INTHORN, D., O. LERTSUPOCHAVANICH, S. SILAPANUNTAKUL, D. SUJIRARAT, and B. INTARAPRASONG. "Factors Affecting Lead Leaching from Microwavable Plastic Ware Made with Lead-Containing Pigments." Journal of Food Protection 65, no. 7 (July 1, 2002): 1166–71. http://dx.doi.org/10.4315/0362-028x-65.7.1166.
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Although food contact polymers do not normally contain lead, it is suspected that lead may be leached from some microwavable plastic ware items made in Thailand with lead-containing pigments. The purpose of this study was to examine relationships with regard to lead leached from microwavable plastic ware. Four factors were studied: pH, heat level, extraction time, and number of repeated extractions. A total of 243 samples of microwavable plastic ware items locally manufactured in Thailand were used. This study used three pH values (3.5, 4.5, and 6.5) and three heat levels (levels 3, 6, and 9 [170, 500, and 850 W, respectively]). Acetic acid was used both as the extracting agent and for adjusting the pH. Samples were collected at each level at 1, 3, and 5 min, and the amount of leached lead was measured with an atomic adsorption spectrometer. The results of this study show that pH, heat, and extraction time affected the amount of lead leaching from microwavable plastic ware. The amount of lead leaching increased with decreasing pH but increased with increasing heat level and extraction time. On the basis of these three factors, the results of this study indicate that the pH of the extractant (r = −0.592, P < 0.01), the heat level of extraction (r = 0.293, P < 0.01), the extraction time (r = 0.226, P < 0.01), and the number of extractions (r = −0.153, P < 0.01) are related to lead leaching from microwavable plastic ware. The relationship between the pH of the extractant, the heat level of extraction, and the extraction time significantly moderated lead leaching from microwavable plastic ware (R2 = 0.511, P < 0.001). For all factors, the amount of lead leaching was lower than the permissible level of 1 mg/liter specified by the Minister of Public Health. In conclusion, a combination of high acid, prolonged heating, and extraction time accelerated the amount of lead leaching from microwavable plastic ware, but the incidence of lead leaching was negligible.
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Yang, Ling, and Cheng Zheng. "Optimization of the Technology of Extracting Dihydromyricetin from Ampelopsis by Orthogonal Experimental Design." Advanced Materials Research 550-553 (July 2012): 1709–14. http://dx.doi.org/10.4028/www.scientific.net/amr.550-553.1709.
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The optimum extracting condition of dihydromyricetin from ampelopsis was studied. The MAE conditions, such as the extraction solvent volume, extraction temperature, and the period of extraction, were all studied in the orthogonal test. The most suitable conditions for the extractions were showed as follows: the extracting temperature was 95°C,the extracting time was 15min,and the solid-liquid leaching ration was 1:20.
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Cheng, Jun Hua, Jian Zhang, and Di Jiang Wen. "Comparison of Leaching Characteristics of Lead in Waste CRTs." Advanced Materials Research 177 (December 2010): 470–74. http://dx.doi.org/10.4028/www.scientific.net/amr.177.470.
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This study investigates four extraction methods (water extraction, toxicity characteristics leaching procedure (TCLP), modified TCLP with pH control and sequential chemical extraction (SCE)), each representing different liquid-to-solid (L/S) ratios, pH controls, and types of leachant and their effects on the leaching concentration of Pb in cathode ray tubes (CRTs).The results indicated that for extraction with distilled water,the lead leaching concentration (mg/L) decreased with L/S ratio in the range of 2-100. The results also showed that the leaching concentration was strongly pH-dependent in the TCLP and modified TCLP tests. In modified TCLP tests,in the case of pHs lower than 6.3,the leaching concentrations of Pb decreased with an increase in pH. Due to the nature of amphoteric elements, in the case of pHs higher than 7, the Pb leaching concentration increased with increasing pH. In SCE tests, the Pb speciation approached the extractable carbonate bound fraction. Both amounts of Pb leached from the SCE and modified TCLP tests were much higher than those for the regular TCLP and water extraction tests. The initial particle size of samples have great effect on the leachability of Pb from waste CRTs.
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Karimova, L., Y. Kairalapov, T. Tussupbekova, T. Oleinikova, and G. Makasheva. "Hydrometallurgical processing of molybdenum middlings from Shatyrkul-Zhaysan cluster ore." Journal of Mining and Metallurgy, Section B: Metallurgy, no. 00 (2024): 6. http://dx.doi.org/10.2298/jmmb230725006k.
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This research investigates the hydrometallurgical processing of molybdenum middlings extracted from copper-molybdenum ore at the Shatyrkul-Zhaysan cluster in Kazakhstan. Molybdenum intermediate product obtained after selective flotation of the copper-molybdenum concentrate was used, with 0.07% yield, 22.23% molybdenum content, and 74.91% extraction. Mineralogical analysis shows molybdenite and chalcopyrite as the main minerals. Experiments study atmospheric leaching with nitric acid in single-stage and two-stage countercurrent modes to optimize molybdenum extraction and reduce acid consumption. The optimal conditions obtained were: 300 g/L nitric acid, 100 g/L sulfuric acid, 90?C temperature, and 2 hours leaching time in single stage leaching, giving 98.8% molybdenum extraction. Two-stage leaching under optimized conditions allows obtaining 94.3% molybdenum extraction in solutions with lower residual acidity (0.89 g-eq/L) and redox potential (550 mV) without reducing valuable component extractions. Molybdenum extraction reaches 94.3% in the subsequent solvent extraction stage from two-stage leaching solutions. The final product, calcium molybdate containing 46.83% molybdenum, meets commercial grade specifications. This research demonstrates an effective process for the hydrometallurgical production of commercial calcium molybdenite from copper-molybdenum ore, with high molybdenum recovery, reduced acid consumption through two-stage leaching, and minimal hazardous discharges.
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Li, Huan, Elsayed Oraby, Jacques Eksteen, and Tanmay Mali. "Extraction of Gold and Copper from Flotation Tailings Using Glycine–Ammonia Solutions in the Presence of Permanganate." Minerals 12, no. 5 (May 12, 2022): 612. http://dx.doi.org/10.3390/min12050612.
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This study presents the novel idea of a cyanide-free leaching method, i.e., glycine–ammonia leaching in the presence of permanganate, to treat a low-grade and copper-bearing gold tailing. Ammonia played a key role as a pH modifier, lixiviant and potential catalyst (as cupric ammine) in this study. Replacing ammonia with other pH modifiers (i.e., sodium hydroxide or lime) made the extractions infeasibly low (<30%). The increased additions of glycine (23–93 kg/t), ammonia (30–157 kg/t) and permanganate (5–20 kg/t) enhanced gold and copper extractions considerably. Increasing the solids content from 20 to 40% did not make any obvious changes to copper extraction. However, gold leaching kinetics was slightly better at lower solids content. It was indicated that the staged addition of permanganate was unnecessary under the leaching conditions. Recovery of gold by CIL was shown to be feasible, and it improved gold extraction by 15%, but no effect was observed for copper extraction. Percentages of 76.5% gold and 64.5% copper were extracted in 48 h at 20 g/L glycine, 10 kg/t permanganate, 20 g/L carbon, pH 10.5 and 30% solids. Higher extractions could be potentially achieved by further optimization, such as by increasing permanganate addition, extending leaching time and ultra-fine grinding.
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Li, Da Gang, Fu Fang Yuan, Ru Pan Chen, Yun Long Li, Kun Lu Li, and Song Bai Lin. "The Extraction of Polyphenols from Tea Leaves Based on Mechanochemical Methodology and Aqueous Two-Phase System." Advanced Materials Research 834-836 (October 2013): 508–14. http://dx.doi.org/10.4028/www.scientific.net/amr.834-836.508.
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In order to extract tea polyphenols (TPs) by water under room temperature, the mechanochemical methodology was used for leaching process, and then TPs was purified from leaching solution by ethanol and ammonium sulfate aqueous two-phase system. The optimum parameters of mechanochemical methodology leaching TPs were determined by response surface methodology (RSM), which optimum parameters were: Na2CO3content 25~27wt%, solid material particle size D9540~45μm, liquid/solid mass ratio55~60, leaching time 16~18min. The TPs leaching rate was 16.46%. When ammonium sulfate mass composition0.2, ethanol mass composition0.35 as the composite of the extraction system, TPs maximum extraction rate was 93.4%. The maximum yield of TPs was 15.25% on the average, with average purity was 96.54% ultimately. Under such technology, water is only solvent used in TPs leaching at room temperature, and aqueous two-phase system extraction system under mild conditions, avoid the use of toxic solvent, is a green technology for extracting TPs.
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Rasskazov, Igor, Artur Sekisov, and Anna Rasskazova. "In-situ leaching of molybdenum and uranium by percarbonate and chloride-hypochlorite solutions." Записки Горного института 256 (November 10, 2022): 623–31. http://dx.doi.org/10.31897/pmi.2022.60.
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In-situ leaching of molybdenum and uranium is becoming an increasingly common process. The features of the material composition of ores, leading to a decrease in their filtration properties, were considered. Activation leaching with leaching solutions that have undergone electrophotochemical activation before contact with the ore mass were studied. Activation preparation of leaching solutions promotes the synthesis of clustered water molecules with collectivized protons and hydroxyl ions, as well as active forms of oxygen and hydrogen. Cell leaching of molybdenum from mature tailings of the Shakhtaminsk deposit was studied experimentally. After pre-oxidation with an active carbonate solution, a model borehole leaching was carried out with a chloride-hypochlorite solution. Molybdenum extraction on resin a was 85 % in 30 days. Experiments on the percolation leaching of uranium from the ores of the Uchkuduk and Sugraly deposits confirmed the potential possibility of a significant increase in the extraction of uranium by electrophotoactivated percarbonate solutions relative to aqueous solutions of sodium and ammonium carbonate. When leaching with carbonate solutions without an additional oxidizing agent, the extraction of uranium from the Sugraly deposit ore sample was 52 and 59 % (sodium carbonate and ammonium carbonate). The use of hydrogen peroxide as an oxidizing agent made it possible to achieve 87-88 % extraction into pregnant solutions in 21 days without pre-oxidation. The performed studies confirm the processing capability of extracting uranium and molybdenum by percolation leaching in columns and borehole leaching.
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Wen, Kang, Feng Jiang, Xiangyang Zhou, and Zhaoming Sun. "Recovery of Gallium from Corundum Flue Dust by Two-Stage Alkali Leaching, Carbonation, Acid Leaching and Solvent Extraction Process." Metals 8, no. 7 (July 17, 2018): 545. http://dx.doi.org/10.3390/met8070545.
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Flue dust generated during the process of manufacturing corundum is a carrier of critical metal gallium. In this study, a process of alkali leaching-carbonation-acid leaching-solvent extraction was developed to recover and enrich gallium from corundum flue dust. Over 93% of the gallium in corundum flue dust could be recovered through a two-stage alkali leaching process, which consists of 120 min of concentrated alkali leaching in NaOH solution and a subsequent 30-min dilute alkali leaching (after dilution), with an alkali-to-ore mass ratio of 1.2:1. Liquid to solid ratios in two alkali leaching stages were 1.5:1 and 8:1, respectively. The carbonation process was employed to remove high-level Si in alkali leachate. After carbonation and HCl leaching, over 96% of gallium in the NaOH leachate could be dissolved into acid solution. After extracting gallium from the HCl leachate using N235 as extracting agent, 1% NaOH solution was used to strip gallium from the organic phase. The extraction and stripping efficiency of gallium was over 99% and 97%, respectively.
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Knaislová, Anna, Hong Vu, and Petr Dvořák. "Microwave and Ultrasound Effect on Ammoniacal Leaching of Deep-Sea Nodules." Minerals 8, no. 8 (August 14, 2018): 351. http://dx.doi.org/10.3390/min8080351.
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The influence of ultrasound and microwaves on extraction of copper, nickel, and cobalt from manganese deep-sea nodules by reductive ammoniacal leaching in the presence of ammonium thiosulfate as a reducing agent was studied. The ultrasonic ammoniacal leaching provides higher metals extraction, while the effect of microwaves on the metals extraction under the studied leaching conditions is insignificant. In general, increasing leaching temperature increases significantly extraction of the metals of interest. At high temperatures, extraction efficiencies of copper, nickel, and cobalt decrease over longer leaching duration as a result of decomposition of the metals amino-complexes and reverse precipitation of metals. However, during the ultrasonic leaching at a temperature of 85 °C, the extraction of nickel remains almost unchanged over longer leaching durations and does not follow the decreasing course, observed in the extraction of copper and cobalt. The finding suggests that nickel can be selectively extracted from the nodules by the ultrasonic leaching. The maximal extraction efficiency of copper, nickel, and cobalt was 83%, 71%, and 32%, respectively, when the reductive ultrasonic ammoniacal leaching was carried out at 85 °C for 90 min. In the presence of microwaves, the maximal extraction efficiency of copper, nickel, and cobalt was 67%, 48%, and 8%, respectively, when the reductive ultrasonic ammoniacal leaching was carried out at the output power of 60 W for 210 min.
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Komnitsas, Kostas, Evangelos Petrakis, Olga Pantelaki, and Anna Kritikaki. "Column Leaching of Greek Low-Grade Limonitic Laterites." Minerals 8, no. 9 (August 31, 2018): 377. http://dx.doi.org/10.3390/min8090377.
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In this study, column leaching experiments were carried out to investigate the extraction of Ni and Co from low-grade limonitic laterites from Agios Ioannis mines in central Greece. Tests were carried out in laboratory Plexiglas columns using H2SO4 as leaching solution. Parameters determining the efficiency of the process, i.e., acid concentration (0.5 M or 1.5 M) and addition of 20 or 30 g/L of sodium sulfite (Na2SO3) in the leaching solution, were also studied. Upflow transport of the leaching solution with the use of peristaltic pumps was carried out, while the pregnant leach solution (PLS) was recycled several times over the entire test duration. The concentration of Ni, Co, Fe, Ca, Al, Mg, and Mn in the PLS was determined by Atomic Absorption Spectroscopy (AAS). The ore and the leaching residues were characterized by different techniques, i.e., X-ray fluorescence (XRF), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry and thermogravimetry (DSC/TG). The experimental results showed that (i) Ni and Co extractions increased with the increase of H2SO4 concentration—60.2% Ni and 59.0% Co extractions were obtained after 33 days of leaching with 1.5 M H2SO4; (ii) addition of 20 g/L Na2SO3 in the leaching solution resulted in higher extraction percentages for both metals (73.5% for Ni and 84.1% for Co, respectively), whereas further increase of Na2SO3 concentration to 30 g/L only marginally affected Ni and Co extractions; and (iii) when leaching was carried out with 1.5 M H2SO4 and 20 g/L Na2SO3, its selectivity was improved, as deduced from the ratios Ni/Mg, Ni/Ca and Ni/Al in the PLS; on the other hand, the ratio Ni/Fe dropped as a result of the higher Fe extraction compared with that of Ni.
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Dadakhodzhiev, A. T., O. K. Muratkulov, D. Kh Yakibovа, O. K. Yunusov, L. S. Rakhimovа, and N. M. Abdulatipova. "Some Results of the Study on the Processing of Spent Vanadium Catalysts." Ecology and Industry of Russia 27, no. 2 (February 1, 2023): 32–36. http://dx.doi.org/10.18412/1816-0395-2023-2-32-36.
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Studies on the extraction of vanadium(V) oxide from spent vanadium catalysts by sulfate and soda-alkaline leaching were carried out at OJSC Maksam-Chirchik and OJSC AGMK. The extraction method of vanadium compounds from spent vanadium catalysts was presented. The feasibility of extracting vanadium from spent catalysts by sulfuric acid leaching followed by treatment with an ammonia solution was confirmed.
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Zhang, Jiangang, Xinyue Zhang, Xiangdong Su, Haijun Du, Yongzhong Lu, and Qinglian Zhang. "Rare Earth Extraction from Phosphogypsum by Aspergillus niger Culture Broth." Molecules 29, no. 6 (March 13, 2024): 1266. http://dx.doi.org/10.3390/molecules29061266.
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The extraction of rare earth elements (REEs) from phosphogypsum (PG) is of great significance for the effective utilization of rare earth resources and enhancing the resource value of PG waste residues. This study used Aspergillus niger (A. niger) fungal culture filtrate as a leaching agent to investigate the behavior of extracting REEs from PG through direct and indirect contact methods. According to the ICP-MS results, direct leaching at a temperature of 30 °C, shaking speed of 150 rpm, and a solid–liquid ratio of 2:1, achieved an extraction rate of 74% for REEs, with the main elements being yttrium (Y), lanthanum (La), cerium (Ce), and neodymium (Nd). Under the same conditions, the extraction rate of REEs from phosphogypsum using an A. niger culture filtrate was 63.3% higher than that using the simulated organic acid-mixed solution prepared with the main organic acid components in the A. niger leachate. Moreover, the morphological changes observed in A. niger before and after leaching further suggest the direct involvement of A. niger’s metabolic process in the extraction of REEs. When compared to using organic acids, A. niger culture filtrate exhibits higher leaching efficiency for extracting REEs from PG. Additionally, using A. niger culture filtrate is a more environmentally friendly method with the potential for industrial-scale applications than using inorganic acids for the leaching of REEs from PG.
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Mu, Yong Wei, Sheng Hua Zhang, Ying Shi Zhao, Qiang Qiang Yang, Yong Wei Fang, Yun Gang Li, Jian Tao Liu, and Zhi Jie Wu. "Summary of Progress in Extracting Vanadium." Applied Mechanics and Materials 598 (July 2014): 60–65. http://dx.doi.org/10.4028/www.scientific.net/amm.598.60.
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This paper mainly summarizes the vanadium leaching process from bone coal, steel slag containing vanadium, catalystcontaining vanadium, including their leaching condition , application circs and these materials’ respective merits and faults under production process. bone coal and steel slag containing vanadium are the usual raw materials and the extracting of vanadium are divided into full wet extraction method and roasting-wet extraction method.The later applied more widely. At the same time, give some short introduction of other new method such as selective precipitation ,slurry electrolysis ,microbial leaching and so on.
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Feng, Qin, An Jing Li, Yuan Fei An, Bin Zhang, and Ying Qian Zhao. "Research Development on Separation and Extraction of Selenium and Mercury." Solid State Phenomena 330 (April 12, 2022): 161–68. http://dx.doi.org/10.4028/p-i040t7.
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The application of selenium and mercury and the raw materials for extracting selenium and mercury were introduced. The current separation and extraction processes of selenium and mercury were described in detail, including pyrometallurgy and hydrometallurgyprocess, in addition to oxygen pressure leaching method and complexacid leaching method.
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Munir, Badrul, Sulaksana Permana, Anggita Amilia, Ahmad Maksum, and Johny W. Soedarsono. "Initial Study for Cerium and Lanthanum Extraction from Bangka Tin Slag through NaOH and HClO4 Leaching." MATEC Web of Conferences 269 (2019): 07003. http://dx.doi.org/10.1051/matecconf/201926907003.
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The global demand for rare earth elements have increased dramatically for the last decade as more and more devices use rare earth elements as key for their advanced properties. The paper explores the possibilty to recover cerium (Ce) and lanthanum (La) in Bangka tin slag (BTS) involving roasting at 900°C, water-quenching, and two leachings, 8M NaOH leaching and HClO4 leaching at concentrations of 0.1M, 0.4M, and 0.8M. HClO4 leaching causes Ce and La contents to decrease to 0.47% for 0.1M, 0.51% for 0.4M, and 0.59% for 0.8M. On the other hand, 8M NaOH optimizes cerium and lanthanum contents up to 4.35% and 1.45%, respectively.
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Shoppert, Andrei, Irina Loginova, Julia Napol’skikh, Aleksey Kyrchikov, Leonid Chaikin, Denis Rogozhnikov, and Dmitry Valeev. "Selective Scandium (Sc) Extraction from Bauxite Residue (Red Mud) Obtained by Alkali Fusion-Leaching Method." Materials 15, no. 2 (January 7, 2022): 433. http://dx.doi.org/10.3390/ma15020433.
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Bauxite residue, known as “red mud,” is a potential raw material for extracting rare-earth elements (REEs). The main REEs (Sc, Y, La, Ce, Nd, Nb, and Sm) from the raw bauxite are concentrated in RM after the Bayer leaching process. The earlier worldwide studies were focused on the scandium (Sc) extraction from RM by concentrated acids to enhance the extraction degree. This leads to the dissolution of major oxides (Fe2O3 and Al2O3) from RM. This article studies the possibility of selective Sc extraction from alkali fusion red mud (RMF) by diluted nitric acid (HNO3) leaching at pH ≥ 2 to prevent co-dissolution of Fe2O3. RMF samples were analyzed by X-ray fluorescence spectrometry (XRF), X-ray diffraction (XRD), electron probe microanalysis (EPMA), and inductively coupled plasma mass spectrometry (ICP-MS). It was revealed that Sc concentration in RMF can reach up to 140–150 mg kg−1. Sc extraction was 71.2% at RMF leaching by HNO3 at pH 2 and 80 °C during 90 min. The leaching solution contained 8 mg L−1 Sc and a high amount of other REEs in the presence of relatively low concentrations of impurity elements such as Fe, Al, Ti, Ca, etc. The kinetic analysis of experimental data by the shrinking core model showed that Sc leaching process is limited by the interfacial diffusion and the diffusion through the product layer. The apparent activation energy (Ea) was 19.5 kJ/mol. The linear dependence of Sc extraction on magnesium (Mg) extraction was revealed. According to EPMA of RMF, Sc is associated with iron minerals rather than Mg. This allows us to conclude that Mg acts as a leaching agent for the extraction of Sc presented in the RMF in an ion-exchangeable phase.
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Wahab, Wahab, Deniyatno Deniyatno, Marthines Saranga, and Yayat Iman Supriyatna. "Kinetics Study of Leaching Ore Nickel Laterite Using Hydrochloric Acid in Atmosphere Pressure." RISET Geologi dan Pertambangan 32, no. 1 (June 30, 2022): 14. http://dx.doi.org/10.14203/risetgeotam2022.v32.1163.
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Leaching of nickel laterite ore at atmospheric pressure is a leaching method that can be operated at >100⁰C temperatures in an atmospheric pressure, which is applicable to a low-grade laterite ore. This research aimed to study the effect of temperature, acid concentration, and leaching time on nickel extraction percentage and the leaching kinetics. Hydrochloric acid (HCl) was used as a leaching agent and several variables were applied, i.e., temperature (80⁰C, 90⁰C, 100⁰C), HCL concentration (5 M, 6 M, 7 M), and leaching duration (120 minutes, 150 minutes, 180 minutes) to investigate their effect on nickel extraction percentage. In addition, the kinetics of the leaching process was studied using a Shrinking Core Model. The results showed that the percentage of nickel extraction increased with increasing temperature, HCl concentration, and leaching time. The lowest percentage of nickel extraction of 51.29% was obtained when 80⁰C, five molar HCl, and 120 minutes leaching duration were applied. In contrast, The highest percentage of nickel extraction of 97.22% was obtained at 100⁰C, seven molar HCl, and 180 minutes of leaching time. The kinetics study results show that diffusion through the unreacted solid product layer controls the nickel leaching rate.
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Yusifova, N. V., A. M. Pashajanov, N. I. Ismailov, and T. M. Ismailov. "SOLVENT EXTRACTION OF COBALT FROM LEACHING SOLUTIONS OF COBALT ORES." Azerbaijan Chemical Journal, no. 2 (June 19, 2023): 178–85. http://dx.doi.org/10.32737/0005-2531-2023-2-178-185.
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The extraction of cobalt with amines has been studied in the most detail. The article presents experimental data obtained in the study of cobalt extraction from leaching solutions of cobalt ores with a mixture of tributylamine (TBA) in toluene and hexane. The dependence of the extraction degree and distribution coefficient of cobalt on pH, time, and the ratio of aqueous and organic phases have been studied. It has been shown that cobalt is maximally extracted with TBA in toluene in the pH range of 3-5 for no more than 5-10 minutes; in this case, 98% of cobalt extraction is achieved. The developed method of cobalt extraction with organic extractants can be widely used in non-ferrous metallurgy
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Huang, Jing, Yingbin Wang, Guanxuan Zhou, and Yu Gu. "Investigation on the Effect of Roasting and Leaching Parameters on Recovery of Gallium from Solid Waste Coal Fly Ash." Metals 9, no. 12 (November 22, 2019): 1251. http://dx.doi.org/10.3390/met9121251.
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Coal fly ash (CFA) provides important resources of gallium, which is regarded as an irreplaceable material in many technologies. A prospective roasting reagent assisted acid leaching process was proposed for the purpose of extracting gallium. The extraction efficiency of gallium by NaF (sodium fluoride) roasting followed by HNO3 (nitric acid) leaching process was demonstrated. The effect of roasting temperature, roasting time, the NaF-CFA mass ratio, acid leaching temperature, acid leaching time, and acid concentration were investigated. The results revealed that under optimal conditions (roasting temperature of 800 °C, roasting time of 10 min, acid leaching in 2 mol/L HNO3 for 1 h, and the NaF-CFA mass ratio of 0.75:1), 94% of gallium was extracted. Compared to previous studies, the process is a cost-effective method which can greatly shorten reaction time. It can reduce environmental pollution as it requires fewer acid reagents with low concentration and additives. It is expected to provide a method for the extraction of gallium from CFA.
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Benavente, Oscar, Ma Cecilia Hernández, Evelyn Melo, Luis Ardiles, Víctor Quezada, and Yuri Zepeda. "Copper Extraction from Black Copper Ores through Modification of the Solution Potential in the Irrigation Solution." Metals 9, no. 12 (December 11, 2019): 1339. http://dx.doi.org/10.3390/met9121339.
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This article presented the behavior of ores containing black copper under acid leaching. The solution potential was modified by adding agents, and five leaching conditions were evaluated, one as a control based on sulfuric acid leaching (conventional), and the others by changing the solution potential with: ferrous sulfate (FeSO4), white metal (Cu2S), sulfur dioxide (SO2), and ozone (O3). Leaching behavior was evaluated with laboratory bottle (ISO-pH) and column leaching tests. Two ores samples from the Lomas Bayas mine were used. The samples, identified as low (LG) and high grade (HG), were characterized as 0.13–0.25% Cu and 0.15–0.38% Mn, respectively. The mineralogical analysis indicated that black copper represented around 20% of total Cu (0.05% Cu). The results of the bottle tests indicated that the solution potential decreased with the addition of reducing agents, while the copper extraction rate with the HG sample increased to 83.7%, which exceeded the extraction rate obtained by conventional acid leaching by 25%. Ozone did not favor the extraction of Mn and Cu extraction when the solution potential increased. Cu and Mn extraction were directly related. The results of the column leaching tests showed that it was possible to maintain the solution potential at values below 600 mV (SHE) with the addition of white metal and sulfur dioxide while obtaining the highest copper extraction rate of approximately 60%, which was 18% higher than the rate obtained with conventional leaching. Sulfuric acid consumption was 11 kg/t over 45 days of leaching.
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Jiang, Chen Guang, and Qing Jie Tang. "Study on Extracting Technology of Vc from Momordica charantia." Advanced Materials Research 781-784 (September 2013): 606–9. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.606.
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Balsam pear was used as the research object in experiment, the technological parameters were studied such as the way of crushing, leaching agent type and its concentration, solid-liquid ratio, ultrasonic extraction temperature, time, power's influence on the extraction yield of Vc, and the ultrasonic extraction time, temperature, ultrasonic power on the L9 (34) orthogonal test analysis. Results showed that bitter melon slices, and solid-liquid ratio is 1:7, citric acid as leaching agent and the concentration of 1%, ultrasonic power is 80 w, leaching temperature 30 °C, 40 min leaching time, leaching of balsam pear Vc the highest rate.
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Manzila, Archippe Ngwey, Thandazile Moyo, and Jochen Petersen. "A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining." Minerals 12, no. 10 (October 14, 2022): 1291. http://dx.doi.org/10.3390/min12101291.
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Mercury amalgamation is the method of choice to recover gold in artisanal and small-scale gold mining (ASGM). However, despite the low cost and simplicity of this method, the use of mercury presents serious health and environmental risks, as well as low efficiency in gold extraction. This study investigates the application of cyanide and thiosulphate leaching as alternatives to mercury amalgamation. This investigation was undertaken by conducting leach experiments using cyanide at 1 g/L, 3 g/L, and 5 g/L, and ammonium thiosulphate at 0.1 M and 0.5 M, on three ore samples originating from an artisanal mining area in Zimbabwe. The operating conditions (T = 26 °C, solids loading: 30%, particle size: −300 + 150 µm) were selected to mimic as closely as possible the conditions of artisanal mining processes. It was found that cyanide leaching was the better performing technology compared to thiosulphate leaching, as it achieved gold extractions of 71.6%, 69.7%, and 67.8% for the three ore samples (Sample 1, Sample 2, and Sample 3, respectively), whereas thiosulphate leaching achieved gold extractions of 54.1%, 35.6%, and 38.0% for the three ores, respectively. Both methods outperformed mercury amalgamation, which typically achieves gold recoveries of 30%–50%. Studying the minerology of the ores, using XRF, XRD, QEMSCAN, SEM-EDS, and a diagnostic leach, revealed the presence of sulphide minerals hosting refractory gold which contributed to the low gold extractions observed. Besides achieving higher gold extraction, cyanide leaching proved to be a system that is easier to control compared to thiosulphate leaching, making it much more attractive to artisanal miners.
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Patel, Bhargav C., Devyani R. Tipre, and Shailesh R. Dave. "Biphasic Leaching Operation for the GMDC Polymetallic Bulk Concentrate." Advanced Materials Research 828 (November 2013): 117–21. http://dx.doi.org/10.4028/www.scientific.net/amr.828.117.
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A biphasic leaching operation was employed for the extraction of copper and zinc from the GMDC polymetallic bulk concentrate (PBC). Biogenerated ferric was used in cyclic manner for fed batch metal extractions from the PBC for four cycles under the pre-optimized conditions. Zn extraction was gradually decreased with each succeeding fed-batch cycle and it resulted in 67.89, 62.46, 47.37 and 14.74% of Zn extraction in 1st, 2nd, 3rd and 4th cycle respectively. In case of copper the extraction pattern was 86.63, 81.98, 75.58 and 46.51% Cu extraction in 1st, 2nd, 3rd and 4th cycle respectively. The leachate generated in each cycle was added in 15.0 L down flow packed bed column reactor having biofilm of developed consortium SR-BH-L for the ferrous bioregeneration and the obtained maximum IOR was 2650 mg/L/h. Overall results indicated that use of bioregenerated ferric iron from the leachate yielded as high as 52.2 and 2.6 g/L Zn and Cu respectively in the solution at the end of 4th cycle. This metal concentration in the leachate is quite acceptable for economical solvent extraction process.
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Kansomket, Chatisa, Thanapon Chandakhiaw, Natthicha Ma-ud, Tanongsak Yingnakorn, Tapany Patcharawit, and Sakhob Khumkoa. "Study on Leaching of Molybdenum from a Spent HDS Catalyst." Materials Science Forum 1009 (August 2020): 143–48. http://dx.doi.org/10.4028/www.scientific.net/msf.1009.143.
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The aim of this study is to investigate the extraction of molybdenum from the spent HDS catalyst. The experiment was performed by using the pyro-hydrometallurgical process; calcination and leaching. The spent catalyst was calcined at different temperatures in order to investigate the effect of calcination temperature on the recovery of molybdenum in the subsequent process. Leaching of the calcined samples was subsequently performed by using the different concentrations of leaching reagent. The leaching was conducted by varying the concentration of NaCO3 of 20 g/L, 30 g/L and 40 g/L with a fixed leaching temperature of 90°C, a S/L ratio (weight of calcined sample/volume of leaching reagent) of 100 g/L and leaching time of 1 hrs. under the stirring condition at a speed of 250 rpm. It was found that carbon and sulfur contained in the spent HDS catalyst could be reduced by the calcination process and resulting in enhanced extraction efficiency of molybdenum. The extraction efficiency of molybdenum increased with increasing concentration of leaching reagent. At a certain concentration of leaching reagent, the extraction efficiency of the sample calcined at lower temperatures was higher than the sample which was subjected to calcination at a higher temperature.
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Prem, Priscilla, Ward Burgess, Jon Yang, and Circe Verba. "Extraction Kinetics of Rare Earth Elements from Ion-Adsorbed Underclays." Minerals 13, no. 12 (November 30, 2023): 1503. http://dx.doi.org/10.3390/min13121503.
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Citric acid has been identified as an environmentally sustainable organic acid capable of leaching up to ~30% of easily accessible REEs from underclay material. An analysis of the leaching profiles was performed to discern the reaction rates, extraction efficiencies, and potential leaching mechanisms of REEs and cations of interest from ion-adsorbed underclays. The initial leaching stage follows a slow intraparticle diffusion mechanism followed by a second stage controlled by a mixed diffusion regime. The leaching profiles of Ca and P were similar to those of REEs, suggesting that REEs are most likely derived from mineral surfaces such as hydroxyapatite or crandallite rather than predominately from underclays. Fitting to a modified diffusion control model found diffusion-controlled leaching to be the primary mechanism whereas non-diffusive mechanisms made up about 22% of the extracted REEs. Gangue cations associated with underclays had less non-diffusive leaching than REE species, indicating that their leaching kinetics may be dominated by diffusion from within the material or potentially from product layer formation. Fitting to Boyd plots further indicated that REEs were leached following intraparticle diffusion control. These results have important implications for the development of more efficient and sustainable methods for extracting REEs or critical minerals from alternative feedstocks.
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Deng, Zixian, Elsayed Oraby, Huan Li, and Jacques Eksteen. "Extraction of Copper from Chalcopyrite Using Alkaline Glycine–Ammonia Solutions." Minerals 12, no. 12 (November 25, 2022): 1507. http://dx.doi.org/10.3390/min12121507.
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Chalcopyrite is well known as being refractory to conventional leaching approaches at atmospheric pressure. The current study investigated a hybrid approach using aqueous ammonia as a pH modifier for glycine-based lixiviant systems to leach copper from chalcopyrite while maintaining surface refreshment using ceramic media at room temperature. The glycine–ammonia system exhibited significantly better copper extraction than the traditional glycine–NaOH system. A copper extraction of 91.5% was achieved after 72 h of leaching by using 0.71 M ammonia, at a Gly:Cu molar ratio of 4:1, by using a solid content of 1%, with a ceramic media: solid ratio of 3:5 and at ambient temperature. Adding ceramic beads during leaching led to a breakup of particles and a refreshment of particles’ surfaces that significantly improved the copper extraction. At a solid content of 10%, oxygen is essential for leaching; a copper extraction of 95.4% was achieved with oxygen injection, while only 33.4% copper extraction was obtained without introducing oxygen. A kinetic analysis indicates that the leaching rate is limited by combined liquid film diffusion and diffusion through the product layer. A conceptual flowsheet is proposed, where chalcopyrite concentrate can be extracted by a leaching–grinding process and copper can be recovered by a solvent extraction–electrowinning circuit.
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Rao, Mingjun, Tao Zhang, Guanghui Li, Qun Zhou, Jun Luo, Xin Zhang, Zhongping Zhu, Zhiwei Peng, and Tao Jiang. "Solvent Extraction of Ni and Co from the Phosphoric Acid Leaching Solution of Laterite Ore by P204 and P507." Metals 10, no. 4 (April 23, 2020): 545. http://dx.doi.org/10.3390/met10040545.
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An alternative process of pre-roasting, phosphoric acid leaching followed by solvent extraction of a limonitic laterite ore was described in this work, with emphasis on the solvent extraction of Ni and Co from the phosphoric acid leaching solution by P204 and P507. First, the pH value of the leaching solution was adjusted using ammonia to reduce the content of Al3+ and Fe3+ by precipitation, then the content of Al3+, Fe3+ and Mn2+ were further decreased by extraction using P204. At last, Ni2+ and Co2+ were separated by three-stage extraction using P507. After extraction, the extraction ratio of Co2+ was 96.61%, while that of Ni2+ was 12.32%, and the selective extraction of Ni2+ and Co2+ could be realized.
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Karimova, L. M., and A. Argyn. "Studies into copper extraction by Acorga M5774 from heap leaching solutions of the Sayak deposit." iPolytech Journal 26, no. 3 (October 8, 2022): 545–53. http://dx.doi.org/10.21285/1814-3520-2022-3-545-553.
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The process of extraction/re-extraction of copper from heap leaching solutions using the Acorga M5774 Solvay extractant (Sytec, Belgium/USA) representing a modified aldoxime (5-nonylsalicylaldoxime) was studied. This extractant is characterized by a high effectiveness and a large selectivity of copper to iron, thus enabling a more rapid phase separation. During experiments, a pregnant leach solution obtained after the percolation leaching of the Sayak deposite ore (Republic of Kazakhstan) was used, g/dm3: H2SO4 – 11.67, Сu – 2.44, Fe – 2.613, Al – 0.345, Si – 0.127, Zn – 0.05, рН = 1.85. The main parameters and effectiveness of the extractant were studied by plotting extraction and re-extraction isotherms, as well as by simulating the closed cycle processing sequence and determining the level of copper extraction at the liquid extraction stage. The extraction/re-extraction of copper from pregnant leach solutions was studied. An aliphatic product of Elixore 205 (Total, France) was used as an extractant diluent, with the amount in the organic phase equal to 90%. Based on the conducted studies, extraction and re-extraction isotherms were plotted. In the liquid extraction process, simulated using the obtained isotherms, the extraction of copper comprised 96.18% (at an organic/aqueous phase ratio of 1.1) with a reagent saturation of 79%. The dependence of iron transfer from the organic phase on the saturation of organic phase with copper was obtained. Thus, the performed studies confirmed the effectiveness of the Acorga M5774 extractant for the purposes of extracting copper from pregnant leach solutions obtained during heap leaching of the Sayak deposit ore.
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Dong, Ling, Yu Li, Jie Yan, and Xin Qian Shu. "Efficient Extraction of SiO2 and Al2O3 from Coal Gangue by Means of Acidic Leaching." Advanced Materials Research 878 (January 2014): 149–56. http://dx.doi.org/10.4028/www.scientific.net/amr.878.149.
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Coal gangue is mainly composed of SiO2, Al2O3 and other components. It is a huge reserve of aluminum and silicon resources. The coal gangue stockpiles in China is more than 5 billion tons at present, of which contain Al2O3 more than 1 billion tons, SiO2 more than 2.5 billion tons. It will make supplement for the lack of bauxite resources in China to some extent by extracting Al2O3 with appropriate methods. In the same time, it will meet the strong demand of national economic growth for aluminum and silicon requirement, and to ensure the safety of national mineral resources. Research for extraction of Al2O3, SiO2 by acid leaching way was carried out in this paper. The influence of acid material ratio, leaching temperature, and leaching time on Al2O3, SiO2 extraction was dealt with in detail. Al2O3, SiO2 in accordance with China national products standard were obtained by optimization of the leaching conditions and parameters.
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del Mundo Dacera, D., and S. Babel. "Use of citric acid for heavy metals extraction from contaminated sewage sludge for land application." Water Science and Technology 54, no. 9 (November 1, 2006): 129–35. http://dx.doi.org/10.2166/wst.2006.764.
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Recent studies revealed that organic acids such as citric and oxalic acids seemed to be more promising as chemical extracting agents for removal of heavy metals from contaminated sludge, since they are biodegradable and can attain a higher metal extraction efficiency at mildly acidic pH compared to other extracting agents. Results of a lab-scale study on the efficiency of citric acid in the extraction of chromium (Cr), copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn) from anaerobically digested sludge, revealed that citric acid seemed to be highly effective in extracting Cr (at 100%), Cu (at 88%), Ni (at 98%) and Zn (at 100%) at pH 2.33, mostly at 5 days leaching time except for Cu and Zn, which are at 1 day and 2 h contact times respectively. Lead removal at the same pH was also high at 95% but at a longer leaching time of 11 days. At pH 3, citric acid seemed to be highly effective in extracting Pb (at 100%) at 1 day leaching time, although higher removals were also attained for Ni (70%) and Zn (80%) at only 2 h leaching time. Chemical speciation studies showed that Cr, Cu and Ni in the sludge sample seem to predominate in residual fractions, while Pb and Zn were found mostly bound to organic and inorganic matter forms, hence the potential of the sludge for land application.
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Shubina, Marianna V., and Elena S. Makhotkina. "Analysis of the Leaching Stage Effect on the Vanadium Extraction from Technogenic Raw Materials." Materials Science Forum 1052 (February 3, 2022): 462–66. http://dx.doi.org/10.4028/p-27ijw5.
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As a result of titanomagnetite iron ore processing, technogenic waste is formed in the form of vanadium-containing slags. The industrial processing of these slags is important to improve the environmental situation in industrial regions and expand vanadium raw material base. The study purpose was the vanadium extraction from slags of titanomagnetite ore processing (ITmk3 process slag and JSC “EVRAZ NTMK” slag) in the soluble vanadate form. Research tasks: hydrometallurgical vanadium extraction from slags of different chemical composition using soda technology; determination of the leaching mode effect (temperature and duration) on the vanadium extraction degree. Experimental samples in the form of slag and soda Na2CO3 mixture were processed to oxidative roasting and subsequent water leaching at different temperatures from 50 °C to 80 °C for 1, 2 and 3 hours. In the resulting solutions the vanadium content was determined with X-ray fluorescence spectroscopy (XRF). Analysis of the research results showed that the slag chemical composition and the water leaching conditions had a significant effect on vanadium extraction degree. The vanadium extraction degree from the JSC “EVRAZ NTMK” slag was 2 – 2.5 times higher than from the ITmk3 process slag after applying the same leaching modes. The highest degree of vanadium extraction was obtained after leaching at a temperature of 80 °C for 3 hours. These leaching modes increased the vanadium extraction degree from the JSC “EVRAZ NTMK” slag to 65 – 87%, and from the ITmk3 process slag to 31 – 33%.
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Zhang, Yanhao, Haohan Zhang, Zhibin Zhang, Chengying Liu, Cuizhen Sun, Wen Zhang, and Taha Marhaba. "pH Effect on Heavy Metal Release from a Polluted Sediment." Journal of Chemistry 2018 (August 23, 2018): 1–7. http://dx.doi.org/10.1155/2018/7597640.
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The performance of Cd, Ni, and Cu release from river sediment at different pH was investigated by a leaching test using deionised water and river water as leachants. Visual MINTEQ geochemical software was used to model the experimental results to predict heavy metal release from sediments. The distribution and speciation of heavy metals in the sediments after leaching test were analyzed by Tessier sequential extraction. Leaching test results showed that the release amounts of Cd, Ni, and Cu are in the range of 10.2–27.3 mg·kg−1, 80.5–140.1 mg·kg−1, and 6.1–30.8 mg·kg−1, respectively, with deionised water as leachant at different pH. As far as the river water was used as the leaching solution in the test, the results show similar metal leaching contents and tendencies to that of the deionised water as leaching solution. The results of Tessier sequential extraction indicate that Cd of residual fraction easily forms obvious precipitate under the acidic condition, especially in the range of pH 0–4 with the residual of Cd over 50% of the total Cd in the sediment. The exchangeable content of Ni decreases with the increase of pH under the range of 0–5. The Fe-Mn oxide fraction of Cu in the sediments changes significantly from pH 0 to pH 9. Based on the effect of pH on the leaching of Cd, Ni, and Cu from the polluted sediment in the tests, more accurate information could be obtained to assess the risk related to metal release from sediments once it is exposed to the changed acid/alkali water conditions.
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Bulaev, Aleksandr, and Vitaliy Melamud. "Selective Acid Leaching of Copper and Zinc from Old Flotation Tailings." Materials Science Forum 989 (May 2020): 554–58. http://dx.doi.org/10.4028/www.scientific.net/msf.989.554.
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The goal of the present work was to develop hydrometallurgical method based on acid leaching, which makes it possible to perform selective extraction of non-ferrous metals from old flotation tailings. Leaching was performed with sulfuric acid solutions (from 0.5 to 10%) and distilled water. Leaching was carried out using percolators and bottle agitator. Percolators were loaded with 100 g of old tailings, and leaching was performed with 100 mL of acid solutions. Pulp density during agitation leaching (S: L) was 1: 5. Two samples of old flotation samples were studied. The first sample of flotation tailings contained 0.26% of copper, 0.22% of zinc, and 17.4% of iron; while the second sample contained 0.36% of copper, 0.23% of zinc, and 23.2% of iron. Percolation leaching made it possible to extract up to 43 and 47% of Cu and Zn from the first sample. Extraction rate was maximum during the leaching with 1 and 2.5% sulfuric acid solutions. During the agitation leaching, the maximum extraction rate was reached with a 2.5% sulfuric acid solution (52 and 54% Cu and Zn), but the leaching rate with all solutions and distilled water differed insignificantly. Percolation leaching made it possible to extract up to 54 and 37% of Cu and Zn from the second sample of tailings, while agitation leaching made it possible to extract up to 34 and 68% Cu and Zn, respectively. The rate of non-ferrous metals extraction from the second sample with water did not differ significantly from that of obtained in the experiments with sulfuric acid solutions. In all experiments, the increase in the H2SO4 concentration led to the increase in concentrations of iron ions in productive solutions, which impedes the extraction of non-ferrous metals from solutions. Thus, it was possible to reach selective leaching of non-ferrous metals and to obtain solutions with relatively low concentrations of iron ions.
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Dahani, Wiwik, Rita Sundari, Subandrio Somali, Irfan Marwanza, and Ivetta Ivetta. "COMPARATIVE STUDY USING LOW COST ACETIC AND SULFURIC ACIDS ON ROASTING AND PEROXIDE FOR LEACHING PROCESS TO EXTRACT PB FROM GALENA." International Journal of Innovation in Mechanical Engineering and Advanced Materials 4, no. 2 (February 7, 2023): 51. http://dx.doi.org/10.22441/ijimeam.v4i2.17135.
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This article aims to present the application of acetic acid and sulfuric acid for lead (Pb) extraction from galena concentrate applying roasting (600oC and 60 min.) and peroxide oxidant (0.5 M) for 60 min. leaching process. Nowadays, lead has been broadly applied for batteries, besides for PVC tubes, chemicals, paint color, and alloys for joint. The peroxide increases the percentage of Pb extraction. This study shows the effect of acid concentrations (1.0 M, 1.5 M, and 2.0 M), temperatures (30, 50, and 70oC), and stirring speed (200, 400, and 600 rpm) on Pb extraction from galena. A particle size of galena ≤ 200 mesh after roasting has been used for leaching process. AAS has been used to determine Pb concentration in solution after leaching process. This study shows that acetic acid is a better leaching agent rather than sulfuric acid due to lead sulfate precipitation. Optimization result shows leaching with acetic acid achieved 35.64 ppm Pb extraction using 2.0 M acetic acid, 50oC, and stirring speed of 200 rpm. The beneficiation of low cost acids as leaching agent is a potential technique for Pb leaching that will be developed for industrial purpose due to its economic reason, simplicity, and fast process.
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Gao, Minglei, Xiangxin Xue, Lanjie Li, He Yang, and Donghui Chen. "Leaching behavior and kinetics of vanadium extraction from vanadium-bearing steel slag." Metallurgical Research & Technology 116, no. 4 (2019): 407. http://dx.doi.org/10.1051/metal/2018129.
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The vanadium-bearing steel slag as solid waste is also one of valuable vanadium-containing resource. Recovering vanadium from the refractory steel slag is a great challenge in the world. A leaching process study using high concentration sodium hydroxide solution was proposed in this laboratory work. The effects of sodium hydroxide concentration, particle size, leaching temperature and the ratio of alkali to slag on the rate of vanadium leaching were determined and the leaching kinetics was presented. It indicates that the leaching rate is highly sensitive to the sodium hydroxide concentration and leaching temperature and increases with increasing temperature and sodium hydroxide concentration. By studying the reaction mechanisms, it was found that the dicalcium silicate, tricalcium silicate and calcium ferrited which co-exist with calcium vanadate in the vanadium-bearing steel slag were gradually exposed and reacted with NaOH media to form Na3VO4. The leaching kinetics was analyzed which indicated that the leaching rate is controlled by the chemical reaction with the apparent activation energy of 51.34 kJ/mol. On the basis of this process, the vanadium can be effectively extracted with a leaching rate of more than 80%. The leaching medium can be recycled. It is an effective and cleaner process for leaching vanadium.
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Sabzezari, Behrouz, Seyed Mohammad Javad Koleini, Sina Ghassa, Behzad Shahbazi, and Saeed Chehreh Chelgani. "Microwave-Leaching of Copper Smelting Dust for Cu and Zn Extraction." Materials 12, no. 11 (June 5, 2019): 1822. http://dx.doi.org/10.3390/ma12111822.
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Industrial wastes may contain high concentrations of valuable metals. Extraction and recovery of these metals have several economic and environmental advantages. Various studies showed positive effects of microwaves as a pretreatment method before the leaching of minerals. However, there are empty rooms for exploring simultaneous microwave and leaching (microwave-leaching) of industrial waste material for the production of valuable metals. This investigation examined the microwave-leaching method to extract copper and zinc from a copper-smelter dust (CSD). The results of microwave-leaching mechanism were compared with conventional heating leaching based on kinetics modelling. The final Cu recovery in the conventional heating and microwave irradiation was 80.88% and 69.83%, respectively. Kinetic studies indicated that the leaching reactions follow diffusion across the product layer. Based on X-ray powder diffraction (XRD) analyses, during conventional experiments sulfate; components formed with high intensity as an ash layer which prevents reagent access to the solid surface and decreases the Cu dissolution. While the sulfate components did not detect in the microwave-leaching residuals which means that microwave irradiation helped to decrease the ash layer formation. Taking all mentioned results into consider it can be concluded that microwave-leaching can be considered as an efficient method for extraction of valuable metals from waste materials.
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Valiyev, Khussain, Aliya Bugubaeva, Aleksandra Nechaeva, Alena Artykova, Vitaliy Melamud, Devard Stom, Anna Boduen, and Aleksandr Bulaev. "The Development of Innovated Complex Process for Treatment of Old Flotation Tailings of Copper-Zinc Sulfide Ore." Molecules 29, no. 7 (March 29, 2024): 1550. http://dx.doi.org/10.3390/molecules29071550.
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The possibility of selective Cu and Zn leaching from the sample of old pyrite tailings, which is one of the most widespread types of solid waste forming during non-ferrous metal production, using sulfuric acid solutions and water was studied. It was shown that water leaching provided selective extraction of Cu and Zn and comparatively low iron ion extraction. At the same time, acid leaching provided the obtainment of pregnant solutions with high ferric ion concentration, which can be used for oxidative leaching of substandard copper concentrates. Water and acid leaching also provided increased Au recovery by cyanidation. The results suggest that acid leaching can be an effective approach for processing old flotation tailings, which allows the extraction of base metals from these wastes and treating flotation tailings for subsequent cyanidation. Effective flotation treatment methods should also provide environmental load reduction, which is caused by the long-term storage of metal-bearing wastes.
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Su, Hai Feng, Chao Chen, Qing Lu, Yan Xuan Wen, and Jing Su. "Kinetics of Leaching Silicon from the Acid Leaching Residue of Pyrolusite." Advanced Materials Research 634-638 (January 2013): 357–61. http://dx.doi.org/10.4028/www.scientific.net/amr.634-638.357.
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The content of SiO2 was more than 60% in the residue of pyrolusite detached manganese by reduction roasted and acid leached, and it was a better siliceous raw material because of less other impurities. Through leaching silicon process in the residue of pyrolusite with alkali at atmospheric pressure, leaching kinetics of silica in the sodium hydroxide solution was researched. The effects of the leaching temperature and the concentration of sodium hydroxide solution on the leaching behavior of silica from acid-leached pyrolusite slag were examinted. It was found that the extracting rate of silica is significantly influenced by the temperature, and the concentration of NaOH solution. The experimental datas were well interpreted with a shrinking core model under chemical control. On the basis of the Arrhenius expression the apparent activation energy of 77.69 kJ/mol and a reaction order of 0.34 for the extraction of silica was evaluated.
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Shirchinnamjil, Nyamdelger, Narangarav Tumen-Ulzii, Nemekhbayar Davaadorj, Khulan Byambasuren, Sarantsetseg Purevsuren, Ulziibadrakh Erdenebat, and Enkhtuul Surenjav. "Treatment of copper-containing leaching residue by sulfation roasting followed by acid/water leaching." Mongolian Journal of Chemistry 24, no. 50 (June 19, 2023): xx. http://dx.doi.org/10.5564/mjc.v24i50.1310.
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This research investigates the extraction of copper from copper-containing leaching residue, which includes 33.45% of copper, 14.14% of iron, 23.87% of sulfur and trace amounts of silver and other elements. Roasting the copper-containing residue under air and oxygen flow convert sulfides into sulfate, followed by water and acid leaching to extract copper. The process parameters, including leaching temperature, sulfuric acid concentration, leaching time, solid-to liquid ratio, and agitation speed, were optimized for both water and acid leaching methods. Results showed that the maximum copper dissolution efficiency was 93.12% with water leaching, and 97.16% with acid leaching. Chemical analysis revealed that the water and acid leaching residue contained 48.13% and 31.64% of iron, respectively. This study provides valuable insights into the process optimization for copper extraction from copper-containing leaching residue, which can inform the development of more efficient and sustainable methods for metal recovery.
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Shoppert, Andrei, Dmitry Valeev, Julia Napol’skikh, Irina Loginova, Jinhe Pan, Hangchao Chen, and Lei Zhang. "Rare-Earth Element Extraction from Low-Alkali Desilicated Coal Fly Ash by (NH4)2SO4 + H2SO4." Materials 16, no. 1 (December 20, 2022): 6. http://dx.doi.org/10.3390/ma16010006.
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Coal fly ash (CFA) obtained from pulverized coal furnaces is a highly refractory waste that can be used for alumina and rare-earth element (REEs) extraction. The REEs in this type of CFA are associated with a mullite and amorphous glassy mass that forms a core-shell structure. In this research, it was shown that complete dissolution of amorphous aluminosilicates from the mullite surface with the formation of the low-alkali mullite concentrate prior to sulfuric acid leaching with the addition of (NH4)2SO4 helps to accelerate the extraction of REEs. The extraction degree of Sc and other REEs reaches 70–80% after 5 h of leaching at 110 °C and acid concentration of 5 M versus less than 20% for the raw CFA at the same conditions. To study the leaching kinetics of the process, the effects of temperature (90–110 °C), liquid-to-solid ratio (5–10), and leaching time (15–120 min) on the degrees of Al and rare-earth element (REEs) extraction were evaluated. After 120 min of leaching at 110 °C and L/S ratio = 10, the extraction of Al was found to be lower than 30%. At the same time, total REEs (TREE) and Fe extraction were greater than 60%, which indicates that a part of the TREE was transferred into the acid soluble phase. After leaching, the residues were studied by laser diffraction (LD), X-ray diffraction (XRD), X-ray fluorescence (XRF), and scanning electron microscopy (SEM-EDS) to evaluate the leaching mechanism and the solubility of Al- and Fe-containing minerals, such as mullite, hematite, and amorphous aluminosilicate.
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Chang, Yong Feng, Chuan Lin Fan, Bin Chuan Li, Xiu Jing Zhai, and Ting An Zhang. "Selective Leaching Nickel from the Pre-Reduced Limonitic Laterite Ore at Atmospheric Pressure." Advanced Materials Research 560-561 (August 2012): 494–98. http://dx.doi.org/10.4028/www.scientific.net/amr.560-561.494.
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In this paper a novel method for selective leaching nickel from pre-reduced laterite ore at atmospheric pressure was reported. The reduced calcine was leached in thin acid liquor to liberate the nickel and iron together firstly. By properly controlling the leaching condition, the leached iron ion could hydrolyze as goethite precipitate and regenerate the acid consumed in the leaching procedure. Finally, the nickel is selectively extracted into the leaching solution. The main factors in the leaching process, such as reduction degree of the laterite ore, acidity of the leaching solution were investigated as influence on the nickel extraction. The test results showed that selectively leaching of nickel could be achieved with an extraction degree up to 90% by reducing most of the iron in the lateritic ore to wuestite and controlling the pH value of the leaching solution below 2.5.
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Prasetyo, A. B., A. Khaerul, W. Mayangsari, E. Febriana, A. Maksum, J. Andinie, F. Firdiyono, and J. W. Soedarsono. "Magnesium extraction of ferronickel slag processed by alkali fusion and hydrochloric acid leaching." Journal of Mining and Metallurgy, Section B: Metallurgy 57, no. 2 (2021): 225–33. http://dx.doi.org/10.2298/jmmb200224018p.
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A research using ferronickel slag, the by-product of ferronickel production, as raw material for magnesium extraction was carried out. It is essential to upgrade the value of ferronickel slag instead of used directly for reclamation materials. Moreover, the accumulation due to increasing ferronickel demand as well as the environmental contamination due to various potentially toxic elements contained in the ferronickel slag could be prevented. The general objective of this study is to utilize the ferronickel slag for magnesium materials. The specific objective is to determine the optimum conditions of magnesium extraction in the process of alkali fusion followed by hydrochloric acid leaching. A novel method for magnesium extraction from ferronickel slag was carried out through reducing silica content followed by acid leaching method. Alkali fusion of the mixture of ferronickel slag and Na2CO3 at 1000?C for 60 minutes, followed by water leaching at 100?C for 60 minutes with solid to liquid percentage of 20 % was carried out to separate the silica. The leaching residue resulted from water leaching was then leached using hydrochloric acid solution to extract magnesium. The leaching temperature and time as well as the hycrochloric acid concentration were varied in the acid leaching process. Alkali fusion process proved the sodium silicate can be generated and that it can be separated in the water leaching to the leached solution. Meanwhile, the leaching residue was leached using hydrochloric acid to extract the magnesium. The highest magnesium extraction percentage is 82.67% that resulted from an optimum acid leaching condition with temperature of 80?C for 30 minutes using 2M HCl solution. Based on the kinetics study, the activation energy (Ea) for the leaching reaction of magnesium at atmospheric pressure between 32?C to 80?C is 9.44 kJ/mol and affected by diffusion and chemical reactions.
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Dadakhodzhaev, A., O. Muratkulov, D. Yakibova, N. Abdutalipova, and M. Bobomurodova. "Extraction of valuable components from spent cadmium and vanadium-containing catalysts." E3S Web of Conferences 371 (2023): 01043. http://dx.doi.org/10.1051/e3sconf/202337101043.
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With the help of water-acid leaching methods, studies were carried out on the extraction of vanadium (V) oxide from spent vanadium-containing catalysts of Maksam-Chirchik JSC, AGMK JSC and Ammophos-Maxam JSC. A new, resource-saving technology for the extraction of vanadium compounds from spent vanadium catalysts has been proposed. In order to reduce the consumption of sulfuric acid in the leaching process, a three-stage aqueous acid leaching was proposed, as a result of which the degree of extraction of vanadium into the solution is more than 98%.
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Liu, Jing Yong, Shui Yu Sun, Yan Bin Xu, Li Zheng, and Shao Song Huang. "Mechanisms and Effects of Extraction Time on the Leachability of Heavy Metals in Sewage Sludge from Guangzhou." Advanced Materials Research 197-198 (February 2011): 1771–75. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.1771.
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The leaching tests of heavy metals in sewage sludge were carried out under different extraction time by the solid waste extraction procedure for leaching toxicity(GB5086.2-1997) of China on the base of the contents of Zn, Cu, Pb, Cr, Mn and Ni elements. The results showed that the sludge was with higher levels of Mn and Zn, followed by Cu and Ni, while the higher toxicity of Pb and Cr was lower, in which the order from the high to low was 1152mg/kg, 987mg/kg, 274mg/kg, 132mg/kg, 104 mg/kg and 87mg/kg, respectively. The extraction time had an important effects on the leaching of heavy metals in sewage sludge, in which the Zn, Ni, Cu leaching contents of the largest in range of 0-8h and Fe, Mn were increasing all through 0-24h. Different extraction time of the leaching amount of metals was very different, which may be related to the process of adsorption/desorption, complexation/dissociation, dissolution-precipitation/co-precipitation and other reactions.
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Rodliyah, Isyatun, Siti Rochani, Sariman Sariman, Suganal Suganal, Datin Fatia Umar, and Pramusanto Pramusanto. "Characterization, beneficiation, and rees extraction of coal bottom ash." Indonesian Mining Journal 25, no. 2 (December 2022): 115–26. http://dx.doi.org/10.30556/imj.vol25.no2.2022.1343.
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Rare earth elements are strategic materials. The elements have critical roles in meeting the needs of raw material for producing the modern industrial products. Most of the REE minerals is available in the form of associated minerals. One of them is coal. In terms of obtaining an overview regarding the possibility of coal to be a source of REEs, a research was carried out by beneficiating the bottom ash of the coal using a shaking table and a magnetic separator, and was followed by extracting the REEs using the alkaline fusion and leaching them using the nitric acid. The results showed that the bottom ash of gasified coal from the Palimanan pilot plant contained cerium, lanthanum, samarium, neodymium, praseodymium, europium, gadolinium, dysprosium, and yttrium, with a total content of 77.85 ppm. Concentrating the REEs using the shaking table and the magnetic separator result in a recovery of 32.96% and 50.5%, respectively. Extracting the REEs by alkaline fusion using NaOH as flux was not promising while leaching with nitric acid was able to extract the REEs with various percentage extraction values, and the highest extraction for Neodymium was 73.46% under conditions of 2M nitric acid leaching and heated at 80°C.
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Tasic, Aleksandra, Ivana Sredovic-Ignjatovic, Ljubisa Ignjatovic, Marija Ilic, and Malisa Antic. "Comparison of sequential and single extraction in order to estimate environmental impact of metals from fly ash." Journal of the Serbian Chemical Society 81, no. 9 (2016): 1081–96. http://dx.doi.org/10.2298/jsc160307038t.
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The aim of this paper was to simulate leaching of metals from fly ash in different environmental conditions using ultrasound and microwave-assisted extraction techniques. Single-agent extraction and sequential extraction procedures were used to determine the levels of different metals leaching. The concentration of metals (Al, Fe, Mn, Cd, Co, Cr, Ni, Pb, Cu, As, Be) in fly ash extracts were measured by Inductively Coupled Plasma-Atomic Emission Spectrometry. Single-agent extractions of metals were conducted during sonication times of 10, 20, 30, 40 and 50 min. Single-agent extraction with deionized water was also undertaken by exposing samples to microwave radiation at the temperature of 50?C. The sequential extraction was undertaken according to the BCR procedure which was modified and applied to study the partitioning of metals in coal fly ash. The microwave-assisted sequential extraction was performed at different extraction temperatures: 50, 100 and 150?C. The partitioning of metals between the individual fractions was investigated and discussed. The efficiency of the extraction process for each step was examined. In addition, the results of the microwave-assisted sequential extraction are compared to the results obtained by standard ASTM method. The mobility of most elements contained in fly ash is markedly pH sensitive.
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Zhang, Ya Li, Xian Jin Yu, Xiao Na Guo, and Xiao Bin Li. "Recovery Technology of Zinc from Hydrometallurgical Zinc Residues." Advanced Materials Research 396-398 (November 2011): 620–23. http://dx.doi.org/10.4028/www.scientific.net/amr.396-398.620.
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In this work, it was aimed to select and propose a feasible as well as an applicable method, or series of methods for the extraction of zinc. After determination of the components of the residue, water leaching, acid leaching and roasting-leaching were performed to reclaim Zn. Roasting-leaching was found to be effectively for Zn extraction by controlling acid mass, roasting duration and temperature as parameters. At the optimum conditions, 0.7 times the amount of H2SO4 at 250 °C for 150 min in roasting, 82.05% of initial Zn content was extracted.
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Botelho Junior, Amilton Barbosa, Denise Crocce Romano Espinosa, James Vaughan, and Jorge Alberto Soares Tenório. "Extraction of Rare-Earth Elements from Silicate-Based Ore through Hydrometallurgical Route." Metals 12, no. 7 (July 1, 2022): 1133. http://dx.doi.org/10.3390/met12071133.
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The European Union and several countries/regions classified the rare-earth elements (REEs), such as lanthanum, cerium, neodymium, and scandium, as critical due to the risk of supply interruption. For this reason, the growing demand for REEs has resulted in forgotten reserves receiving economic interest. So, the search for new sources and the development of chemical process is important, such as silicate-based ore. Since there is almost no literature on the extraction of REEs from this source, a new approach was developed in the present study. Direct leaching and acid baking were studied using sulfuric acid. The effect of the acid concentration, temperature, solid-liquid ratio, oxidizing/reducing medium, and acid dosage were studied. Results showed that the extraction of REEs achieved up to 80% at 90 °C in oxidizing medium, and scandium and iron achieved 13.5% and 65.0%, respectively. For the acid baking experiments, the results were better than direct leaching for REEs at over 85%. The scandium leaching rate was lower than direct leaching. On the other hand, the extraction of iron was lower in acid baking than direct leaching. The iron and scandium extraction rates were higher in lower temperatures (<200 °C) and acid dosages, achieving 50% and 6.3%, respectively. Future studies should explore thermal treatment before acid leaching.
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Peng, Zhonghui, Zhixiang Wang, Zhongchen Han, Yongze Zhu, Yang Li, and Keqiang Xie. "Vanadium–Titanium Magnetite Concentrate, Calcium–Magnesium Composite Roasting and Sulfuric Acid Leaching for Vanadium Extraction from Pellets." Metals 13, no. 6 (June 16, 2023): 1135. http://dx.doi.org/10.3390/met13061135.
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This paper investigated a pellet ore production process in which vanadium was extracted from vanadium and titanium magnetite concentrates using sulfuric acid leaching. Calcium and magnesium were added to the iron ore concentrate during pellet production to produce calcium vanadate and magnesium vanadate after roasting. The pellets were leached with sulfuric acid solution to extract V5+. The resulting pellets had a compressive strength of 3375 N after primary roasting, a good pellet morphology after acid leaching, and simple liquid–solid separation. Under the optimal experimental conditions, the vanadium leaching rate in the pellets reached 77.86%, while the iron leaching rate was only 1.17%. The pellets did not fragment, which was an improvement upon existing vanadium extraction methods. The strength of the pellets after vanadium extraction decreased to 563 N, but after secondary roasting, the compressive strength of the pellets reached 2578 N, which was suitable for blast furnace ironmaking. The roasting and acid leaching experiments showed that the vanadium extraction process resulted in suitable pellet properties. The use of low compound additives can effectively improve the leaching effect, while avoiding the previous problems of too many additives, pellet iron grade reduction, or the pursuit of high vanadium extraction rate pellet breakage and serious high secondary use process costs.
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Khlopytskyi, A., А. Savenkov, О. Bliznjuk, М. Skiba, V. Vorobiova, and N. Masalitina. "Leaching of FeO and CaO by nitric acid from ash-slag wastes of thermal power plants." Voprosy Khimii i Khimicheskoi Tekhnologii, no. 1 (January 2022): 95–99. http://dx.doi.org/10.32434/0321-4095-2022-140-1-95-99.
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In this work, the leaching of iron(II) oxide and calcium oxide from the wastes of thermal power plants by concentrated nitric acid was investigated. A laboratory unit for the study of leaching processes was developed. It was found that the concentrations of iron(II) oxide and calcium oxide in the solution increase with increasing the temperature of the leaching process by nitric acid. The influence of the ratio of reagents on the leaching of iron(II) oxide and calcium oxide from ash and slag wastes was established. An increase in the leaching time in the range of 15–90 minutes positively affects the process of extraction of iron(II) oxide and calcium oxide from ash and slag wastes. The calculated degree of extraction of iron(II) oxide and calcium oxide from ash and slag wastes, as the main criterion for leaching processes, showed that an increase in leaching duration leads to a more complete transition of iron(II) and calcium into solutions. Based on the analysis of the obtained experimental data, the main technological parameters for the extraction of iron(II) oxide and calcium oxide from ash and slag wastes in nitric acid solution have been determined.