Journal articles: 'Bauxite Analysis'

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Atakoglu, Ozge Ozer, and Mustafa Gurhan Yalcin. "Geochemical characterization of the Sutlegen bauxite deposit, SW Antalya." Mining of Mineral Deposits 15, no. 3 (September 2021): 108–21. http://dx.doi.org/10.33271/mining15.03.108.

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Purpose.The purpose is to determine geological and geochemical characteristics of the Sutlegen (Antalya, Turkey) bauxites, to identify the elements that played a major role in their formation. Methods. X-ray diffraction (XRD) mineral phase analysis, X-ray fluorescence (XRF) elemental analysis, plasma-mass spectrometry (ICP-MS), the petrographic and mineralogical analyses, and multivariate statistical methods were used. Findings. The major element content of the ore was determined as Al2O3 (60-35.2 wt%), SiO2 (39.5-0.2 wt%), Fe2O3 (48.4-19.5 wt%), TiO2 (36.9-16 wt%), and P2O5 (0.5-0.1 wt%). The Sutlegen region, which shows epirogenetic action with the uplift of the earth's crust, is generally rich in neritic carbonates. It was revealed that the bauxite ores have undergone moderate and strong laterization as a result of the deferruginization in the environment, and they were classified into four groups as lateritic, ferritic, kaolinitic, and bauxite. The increase in the aluminosilicate minerals, which were formed during the formation of bauxite in the environment was found to be directly proportional to the laterization processes. In this context, it was considered that the lateritic material that was firstly formed in the environment filled the cavities and pores of the karst-type limestones and sedimentary units in the region by superficial transfer phenomena. The bivariate diagrams of Log Cr vs. Log Ni revealed that the bauxite that formed in the region had an ultrabasic source. Originality. In literature, no scientific studies have been found on bauxite mineralization in the Sutlegen deposits that have been operated for a long period. Practical implications. In this context, the geochemical characteristics of bauxites revealed that the source of the laterization process in the region was the ultrabasic igneous rocks. The lateritic material moved by superficial transfer was accumulated on sandstone, claystone, siltstone, and limestone and in karstic cavities; then, it formed karstic bauxite (kaolinitic and bauxite) of different classifications due to the effect of metamorphism.

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Thevi, T., and A. L. Abas. "Effects of Bauxite and Alumina Exposure on Incidence of Cancer - Meta-analysis." Kathmandu University Medical Journal 18, no. 4 (December 31, 2020): 414–19. http://dx.doi.org/10.3126/kumj.v18i4.49256.

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Bauxite is an ore from which Aluminium is produced. Malaysia, once the leading producer of bauxite has reduced production as mining activity has caused community outrage. Due to concerns about health concerns, rising pollution and environmental hazards, the government has revoked the licenses of bauxite miners. We therefore did a meta-analysis to assess the relationship between exposure to Bauxite and Alumina with incidence of various types of cancers. Bauxite mines and alumina refineries. Individuals of all ages exposed to Bauxite and Alumina. Exposure to bauxite and alumina. Incidence due to overall cancers and specific types of cancers. Exposure to bauxite and alumina did not cause variations in incidence of overall cancer and specific types of cancer such as cancer of lip, cancer of the oral cavity and pharynx, cancer of digestive organs and others. We conclude that there is no evidence that bauxite or alumina exposure cause increase incidence of cancer but due to the small number of studies included in this review, we recommend more cohort studies to be done in future.

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Steiner, Timotheus Martin Christoph, Hans-Jürgen Gawlick, Frank Melcher, and Felix Schlagintweit. "Ophiolite derived material as parent rocks for Late Jurassic bauxite: evidence for Tithonian unroofing in the Northern Calcareous Alps (Eastern Alps, Austria)." International Journal of Earth Sciences 110, no. 5 (May 21, 2021): 1847–62. http://dx.doi.org/10.1007/s00531-021-02044-6.

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AbstractIn shallow-water limestones of the Plassen Formation in the Tirolic nappe of the Northern Calcareous Alps, bauxite was formed on karstified and tilted platform margin grainstones to boundstones around the ?Kimmeridgian/Tithonian boundary, or in the Early Tithonian as proven by Protopeneroplis striata Weynschenk, Labyrinthina mirabilis Weynschenk, and Salpingoporella pygmaea Gümbel. The platform established on top of the obducted ophiolite nappe stack. The onset of unroofing at the Kimmeridgian/Tithonian boundary exposed ophiolites to weathering, forming laterites, and bauxites. The weathered ophiolitic material was shed on the tilted, emerged, and karstified platform, where the bauxite accumulated. Continued subsidence led to flooding, and a Tithonian transgressive carbonate sequence sealed the bauxites. XRD analysis of the bauxite yields a composition of mainly boehmite with hematite and some berthierine, kaolinite, and chromite. SEM analysis verified magnetite, hematite, rutile, chromite, zircon, ferropseudobrookite, ilmenite, monazite, xenotime, and garnet distributed in pisoids and within the matrix. The pisoids reach a millimeter in size and partly show cores of older, larger pisoids. The composition of the chromites indicates an ophiolitic origin. Geochemical examination using major- and trace elements points to a mafic andesitic to basaltic parent material contaminated with highly fractionated rocks from an island arc. Formation of Early Tithonian bauxites in shallow-water limestones confirms Middle to Early Late Jurassic ophiolite obduction. This was followed by uplift and unroofing of the orogen from the Kimmeridgian/Tithonian boundary onwards after a period of relative tectonic quiescence with an onset of carbonate platforms during the Kimmeridgian on top of the nappe stack and the obducted Neo-Tethys ophiolites.

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Cui, Tao, Yang Quan Jiao, and Xiao Mei Wang. "Analysis on Sedimentary Environment of Bauxite in Wuchuan-Zheng’an-Daozhen Area, Northern Guizhou." Advanced Materials Research 616-618 (December 2012): 1409–15. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.1409.

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The sedimentary environment of bauxite in Wuchuan-Zheng’an-Daozhen Area has been debated for a long time. Through research on the element B, the sedimentary characteristics of bauxite, the distribution of four different natural types of bauxite and reference paleogeographic data we concluded that bauxite in Wuchuan-Zheng’an-Daozhen Area was a typical sedimentary deposit, with a provenance mainly from south-west. Bauxite was formed in an anoxic bay, which was partly closed and open to north. The sedimentary environment shifted between lacustrine and bay environments, accompanying frequent transgression and regression cycles.

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Sojien, Taylor Moise, Estelle Lionelle Tamto Mamdem, Armand Sylvain Ludovic Wouatong, and Dieudonne Lucien Bitom. "Mineralogical, Geochemical and Distribution Study of Bauxites in the Locality of Bangam and Environs (West Cameroon)." Earth Science Research 7, no. 1 (January 24, 2018): 117. http://dx.doi.org/10.5539/esr.v7n1p117.

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The bauxite duricrust in the Bangam and surroundings is classified into three major storey levels as follows: the upper level on top of the plateaus where the continuous bauxites outcrop in slabs over distances of about 1 km, the intermediate level on top and at the flanks of the hills where the bauxites flush in metric blocks, the lower level at the talwegs where bauxites duricrust are gravels. The average thickness of the duricrust is 9.6m and extends over an area of about 9.5km2. Five types of facies are encountered here: nodular, pisolitic, pseudobreccia, vacuolar and massive. These different facies were carried out by X-ray fluorescence spectrometry, X-ray diffractometric, thermal analysis (ATD / ATG) and by polarizing microscope observation. The results of these analyses show that, gibbsite is the dominant mineral; kaolinite, anatase, hematite, goethite, magnetite and ilmenite are also present. The chemical composition of the major elements that characterize bauxites are 38-60% Al2O3; 2 -22% SiO2 and 9-42% Fe2O3. These values are almost similar to those obtained in Doumbouo-Fokoué, Ghana, Ngaoundal, and Minim-Martap precisely at Briskok prospect. The different minerals paragenesis and geochemistry data show that, the Bangam locality is a bauxite ore deposit in spite of a high content of iron and silicate of some facies, nevertheless, these can be used in some industries.

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Melo, Caio C. A., Rômulo S. Angélica, and Simone P. A. Paz. "A Method for Quality Control of Bauxites: Case Study of Brazilian Bauxites Using PLSR on Transmission XRD Data." Minerals 11, no. 10 (September 28, 2021): 1054. http://dx.doi.org/10.3390/min11101054.

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Available Alumina (AvAl2O3) and Reactive Silica (RxSiO2), the main parameters of bauxite controlled in the beneficiation process are traditionally measured by laborious, expensive, and time-consuming wet chemistry methods. Alternative methods based on XRD analysis, capable to provide a reliable estimation of these parameters and valuable mineralogical information of the ore, are being studied. In this work, X-ray diffraction data in transmission mode was used to estimate AvAl2O3 and RxSiO2 from Brazilian bauxites using the Partial Least Square Regression (PLSR) statistical tool. The proposed method comprises a routine of sample classification according to their similarities by Principal Component Analysis (PCA) and K-means, calibration of the PLSR model for each group of samples, grouping new bauxite samples according to the generated clustering model, and subsequent estimation of the parameters AvAl2O3 and RxSiO2 using the PLSR models for these samples. The results showed good accuracy and precision of the models generated for samples of the main ore lithology. The quality and pre-processing of the XRD data required for this method are discussed. The results demonstrated that this method has the potential to be industrially applied to quality control of bauxites as a rapid and automated procedure.

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Abdulvaliyev, R. A., S. B. Dyussenova, A. I. Manapova, A. Akcil, and U. Zh Beisenbiyeva. "Modification of the phase composition of low-grade gibbsite-kaolinite bauxites." Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 317, no. 2 (June 15, 2021): 94–102. http://dx.doi.org/10.31643/2021/6445.22.

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The known methods of processing low-quality bauxite have a number of disadvantages that make it difficult or impossible to use them in the conditions of production of JSC "Aluminum of Kazakhstan", therefore, it is necessary to effectively develop a technology for preliminary enrichment. Enrichment of low-quality bauxites is possible by separating the clayey - high-siliceous and coarse-crystalline fractions. Electron-microscopic analysis of the original bauxite showed that the coarse-crystalline fraction is tightly pressed by the fine one. The total silicon modulus of the sample is 2.49. The silicon modulus of the fine fraction is 2.19, and that of the coarse fraction is 3.89. When enriching bauxite, as a result of the separation of fines, it is possible to increase the silicon modulus. After the chemical activation of bauxite in a sodium bicarbonate solution, the finely dispersed fraction is effectively separated from the coarse one and the phase composition changes - the calcium silicate phase disappears and the calcite phase is formed. With an increase in the activation temperature, the content of kaolinite and siderite decreases, and the content of quartz and hematite increases. Studies have shown that at temperatures of chemical activation of 120 ° C, duration of more than 120 minutes and 200 ° C, duration of more than 40 minutes, a dawsonite phase is formed in bauxite, which densifies the mineral structure. When determining the optimal regime for carrying out chemical activation, it is necessary to take into account the negative possibility of dawsonite formation.

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Dobra, Gheorghe, Anatoly Kiselev, Laurentiu Filipescu, Vicol Alistarh, Nicolae Anghelovici, and Sorin Iliev. "Full Analysis of Sierra Leone Bauxite and Possibilities of Bauxite Residue Filtration." Journal of Siberian Federal University. Engineering & Technologies 9, no. 5 (August 2016): 643–56. http://dx.doi.org/10.17516/1999-494x-2016-9-5-643-656.

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Fang, Bin Zheng, Hui Li, Jian Wei Cao, Jian Feng Wu, Xiao Hong Xu, and Xi Dong Wang. "Structure and Performance of Calcined Bauxite." Advanced Materials Research 887-888 (February 2014): 305–8. http://dx.doi.org/10.4028/www.scientific.net/amr.887-888.305.

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In order to further broaden the application field of calcined bauxite, using differential thermal analysis-thermo-gravimetry (DTA-TG), X-ray diffraction analysis (XRD), Scanning electron microscopy (SEM) and other testing technology to study and analysis on the high temperature performance of calcined bauxite in this paper. The results show that the main crystal phases of calcined bauxite are corundum and mullite, appearance is layered, granular distribution. Due to the thermal performance of calcined bauxite is optimal, and is expected to be used for the field of high temperature solar thermal heat storage material.

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Cui, Tao. "Mineralizaton Process of the Bauxite in WZD Area." Advanced Materials Research 989-994 (July 2014): 1269–72. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.1269.

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This paper has a comprehensive analysis on mineralizaton process of the bauxite in Wuchuan-Zheng, an-Daozhen (WZD) area, northern Guizhou, China through synthesize former research. Geologic characteristic demonstrates that WZD bauxite is a typical sedimentary deposit, minerogenetic material have experienced a transporting process. Sedimentary environment of WZD bauxite is transition facies. Sedimentary environment is reduced and acidic. Accompanying frequent transgression and regression, bauxite has suffered a leaching process. In the leached period, environment is oxidized and acidic. Leaching process is the most important factor for the information of high grade bauxite. WZD bauxite has experienced several times leaching resulting in the great runoff of Fe and Si. Actually the metallogenetic process of WZD bauxite is a process that Al relative enrichment but Si and Fe runoff.

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Wu, Xirong, Nanxiang Zhen, and Fansheng Kong. "Effect of Characteristics of Different Types of Bauxite Clinker on Adhesion." Applied Sciences 9, no. 22 (November 7, 2019): 4746. http://dx.doi.org/10.3390/app9224746.

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Based on the fact that bauxite clinker has minor thermal conductivity and better skid resistance and wear-resisting property, it can be used in HFST (high friction surface treatment) or the abrasion layer of asphalt mixture to replace or partly replace the existing aggregate. Bauxite clinker is classified into mainly six types according to different chemical composition contents. The selection of bauxite clinker as aggregate is not only for the economic value, but also for improving the adhesion between aggregate and asphalt, which has a certain blindness This study evaluated the characteristics of different types of bauxite clinker. The adhesion of different types of bauxite clinker with asphalt was evaluated by means of agitating hydrostatic adsorption method and surface free energy theory. The effect of characteristic parameters of bauxite clinker on adhesion was evaluated by grey correlation entropy analysis. The results show that Type B and D bauxite clinker aggregates have the best adhesion to asphalt. The outcome of grey entropy correlation analysis shows that the parameters which characterize the structural indexes of bauxite clinker, such as porosity, water absorption and apparent density, have the greatest effect on the adhesion. The results of study can provide some reference for the selection of bauxite clinker, which is used in different types of highway construction, and a theoretical reference for the applicability research of bauxite clinker in asphalt mixture and the improvement of skid resistance and durability of pavement.

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Yang, Tao, Yan Gai Liu, Ding Yun Ye, Qi Wang, Zhao Hui Huang, and Ming Hao Fang. "Phase Behavior Analysis of Low-Grade Bauxite and Rutile by Carbothermal Reduction-Nitridation." Advanced Materials Research 624 (December 2012): 239–43. http://dx.doi.org/10.4028/www.scientific.net/amr.624.239.

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In this study, β-Sialon/Al2O3/TiN diphase powder was synthesized using low-grade bauxite and rutile via carbothermal reduction-nitridation. The phase transitions of low-grade bauxite and rutile in the carbothermal reduction and nitridation process were analyzed by XRD, SEM and EDS. The effects of different reaction parameters such as reaction temperature, rutile addition on the phase composition and microstructure of products were analyzed. The results showed that β-Sialon/Al2O3/TiN powder was prepared using low-grade bauxite and rutile as raw materials and coke as reducing agent by carbothermal reduction-nitridation reaction in flowing nitrogen atmosphere of 0.03 MPa at 1350-1375 °C, for 4 h.

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Wu, Yang, Dai Tagen, and Long Yongzhen. "The Research of the Mineralogical and Element Geochemical Characteristics of Bauxite in Yunfeng, Qingzhen, in Central Guizhou Province, China." Open Chemical Engineering Journal 9, no. 1 (October 22, 2015): 134–42. http://dx.doi.org/10.2174/1874123101509010134.

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The mineralogical and geochemical characteristics of the Yunfeng bauxite in Qingzhen were investigated through the handle specimen observation, thin section analysis, XRD、SEM and Element geochemistry. The mineral analyses reveal that diaspore, kaolinite and chlorite are the major minerals in the bauxite with small amounts of boehmite and pyrite. Geochemical investigations reveal that the main components in the bauxite are Al2O3, SiO2 and TFe2O3, the minorcomponents are TiO2, MgO and P2O5. In the process of weathering, some trace elements, such as Zr, Cr, Nb and Hf, are enriched. Zr vs Hf and Nb vs Ta display higher positive correlation. Trace elements show that Loushanguan Formation is the main source of material for the bauxite formation and there may be exist other precursor rock provide few material for the bauxite formation. Ore deposit formed in a O-poor,reducing Marine sedimentary environment.

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Cui, Tao. "Analysis on Oxidized and Reduced Conditions in Penecontemporaneous Period on the Bauxite in WZD Area." Advanced Materials Research 989-994 (July 2014): 1404–7. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.1404.

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Through systematically geologic survey, observation of drills and rock slices and geochemical analysis this paper have a comprehensive research on oxidized and reduced conditions of bauxite in Wuchuan-Zheng,an-Daozhen (WZD) area. The results shows that color, component, lithology and grade of WZD bauxite have vertical alteration; Metallogenetic environment of WZD bauxite in penecontemporaneous period is oxidized, and from top to bottom, oxygen content is gradually decreased; Not only the similar stratigraphic position in different zone of WZD area have different oxygen content, but also identical stratigraphic position in different period has different oxygen content.

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Yang, Huan Ying, Yong Li, Shu Long Liu, Chang He Gao, Shu Long Ma, and Lin Jun Wang. "Sintering Characters Analysis of the Al₂O₃-86 Homogenized Bauxite." Advanced Materials Research 690-693 (May 2013): 35–39. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.35.

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The present explains sintering characters of the Al2O3-86 homogenized bauxite under wet processes homogenization, which includes classified bauxite mine, wet grinding, vacuum extrusion, sintering in tunnel kiln,etc. DSC and TG reveal an evident peak of absorption heat at 531°C, resulting from the dehydroxylation of bauxite. Green samples held at 550°C*6hrs were heated up to different temperatures, and the properties of weight loss, linear change, bulk density and apparent porosity were measured. The data show that liquid-phase emerge and sintering process goes slowly above 1100°C. At 1500°C, large amounts of liquid-phase form, making liquid-phase sintering have a positive effect. The analysis of XRD and SEM indicate that, corundum grains develop more inadequate and most of the corundums interlace in a compact way, which can separate the widespread liquid phase and improve the sintering capability of homogenized bauxite.

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Nong, Liangqin, Xiying Yang, Lingmin Zeng, and Jingping Liu. "Qualitative and quantitative phase analyses of Pingguo bauxite mineral using X-ray powder diffraction and the Rietveld method." Powder Diffraction 22, no. 4 (December 2007): 300–302. http://dx.doi.org/10.1154/1.2790941.

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X-ray powder diffraction technique and the Rietveld refinement method have been used successfully for the qualitative and quantitative analyses of Pingguo bauxite from Guangxi, China. Qualitative phase analysis shows that the Pingguo bauxite contains diaspore (AlOOH), hematite (Fe2O3), goethite (FeOOH), anatase (TiO2), and kaolinite (Al2(Si2O5)(OH)4). Quantitative Rietveld refinement shows that the weight concentrations of diaspore, goethite, hematite, anatase, and kaolinite for the Pingguo bauxite are 71.9(4)%, 7.0(8)%, 11.3(7)%, 6.5(6)%, and 3.3(9)%, respectively.

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Fang, Bin Zheng, Hui Li, Jian Wei Cao, Jian Feng Wu, Xiao hong Xu, and Xi Dong Wang. "Study and Analysis on the High Temperature Performance of Calcined Bauxite." Advanced Materials Research 960-961 (June 2014): 7–10. http://dx.doi.org/10.4028/www.scientific.net/amr.960-961.7.

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In order to further broaden the application field of calcined bauxite, using XRF and other testing technology to study and analysis on the high temperature performance of calcined bauxite in this paper. The results showed that the sintering temperature range was 1300 ~ 1650°C, the firing line shrinkage, bulk density, bending strength, heat capacity and thermal conductivity was increased gradually, the water absorption and porosity was decreased, the water absorption, volume density and flexural strength of the sample fired at 1650°C were 0.93%, 3.20 g·cm-3 and 182.23 MPa, the specific heat and thermal conductivity were 0.83 kJ·(kg·K)-1 and 9.21 W·(m·K)-1. Due to the thermal performance of calcined bauxite is optimal, and is expected to be used for the field of high temperature solar thermal heat storage material.

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Li, Yan, Zhao Hui Huang, and Yan Gai Liu. "Study on Mineral Composition and Main Mineral Morphology of Bauxite from ZhongXiang, HuBei Province." Key Engineering Materials 512-515 (June 2012): 648–51. http://dx.doi.org/10.4028/www.scientific.net/kem.512-515.648.

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In this paper, the mineral composition and main mineral morphology of bauxite were studied from ZhongXiang deposit, HuBei province. Through Electron Microscope Identification, there are two main rock types, oolitic, bean-like and aphanitic or fine crystalline structure of bauxite. The main mineral morphology is micro-crystalline or flake, crumby forms. The mineral and chemical compositions of samples were investigated by XRD, EPMA analysis tests. The EPMA results showed that Al2O3 content is 47.95% ~ 75.04%, in association with other isomorphous impurities, such as Si, Fe, Ti and Mg in varying proportions. The mineral compositions of bauxite ore are mainly aluminum, iron, silicon minerals, which totally account for from 83.01% to 86.40%. The XRD revealed that diaspore, hematite and kaolinite are the major mineral components in the bauxite ores. The bauxite from ZhongXiang deposits is a type of high diaspore bauxite, partly with clay minerals. Furthermore, the function of bauxite as a good fire-resistant material was discussed.

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Jafar, N., S. R. Nurhawaisyah, S. Widodo, C. A. Chalik, and M. H. Wakila. "Mineralogical Study of Bauxite of Kenco Area, Landak District, West Kalimantan Province, Indonesia." IOP Conference Series: Earth and Environmental Science 1134, no. 1 (January 1, 2023): 012025. http://dx.doi.org/10.1088/1755-1315/1134/1/012025.

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Abstract Indonesia is a country with a tropical climate that allows for high levels of weathering. Bauxite is the result of weathering rocks that have high aluminum content, low iron content, and little quartz content. The formation of bauxite deposits is controlled by source rock which is rich in Al element, tropical climatic conditions, and geomorphological conditions that allow the formation of the accumulation of weathered source rock products. The altered silicate minerals due to weathering result in the silica element being released from the crystal bonds and some iron are released so that the aluminum element is concentrated as a residual precipitate. X-ray diffraction (XRD) analysis on 16 bauxite samples which are estimated to represent the overburden horizon, bauxite ore horizon, clay horizon, and source rock to establish the mineral composition of bauxite. Mineral groups in the overburden horizon, bauxite ore horizon, and clay horizon are alumina, iron, titanium, silicates, carbonates, sulfides, and sulfates, while mineral groups in source rock are iron, titanium, silicate, sulfide, and sulfate. The type of bauxite in the study area is gibbsite bauxite based on the dominant appearance frequency of gibbsite compared to mineral corundum as an alumina group.

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van Chanh, Nguyen, Mitsuhiro Shigeishi, and Tran Quoc Tho. "Inorganic Composite Material Based on Fly Ash, Red Residue from Bauxite Ore for Road Building Projects in Vietnam." Advanced Materials Research 383-390 (November 2011): 2774–81. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.2774.

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The paper present solidifying technology based on geopolymer theory of inorganic composite materials from bauxite, red residue from bauxite ore, fly ash and activators for road building projects in Vietnam. This study describes physical properties and chemical compositions of bauxite, red residue, fly ash and the effects of bauxite-red residue-fly ash-activator mixes on the geotechnical properties of inorganic composite materials. Mixture design and testing procedures for inorganic composite materials. New inorganic composite materials have high durability and ability to water resistance. The presentation also show microstructure analysis of inorganic composite materials based on bauxite residue, fly ash and activators by X-ray diffraction, Infrared spectroscopy (IR), transmission electron microscopy (TEM) display high density, and modified microstructure of inorganic composite materials. Construction method of road using inorganic composite materials is also presented.

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Dwirama Putra, Risandi, Tri Apriadi, Ani Suryanti, Henky Irawan, Tengku Said Raja'I, Try Yulianto, Wiwin Kusuma Atmadja, and Chandra Joei Koenawan. "Preliminary Study of Heavy Metal (Zn, Pb, Cr, As, Cu, Cd) Contaminations on Different Soil Level from Post-Mining Bauxite Production for Aquaculture." E3S Web of Conferences 47 (2018): 02008. http://dx.doi.org/10.1051/e3sconf/20184702008.

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Bauxite production and exploration give negative impact environmental modification and increasing concern pollution of heavy metals. One of an alternative to reduce the negative impact of bauxite post-mining production is by re-utilizing the abandoned bauxite land and necessary exploratory study to obtain the current environmental conditions primarily related to heavy metals in bauxite mining area. Soil and water quality samples from 5 (five) sites based on post-mining activities were used to determine concentration heavy metals of As, Cd, Pb, Zn, Cr, Cu from different soil level. They were also collected for grain size analysis including those of sand and mud percentages along with the mean, and sorting analysis. The mean grain size post-mining bauxite ranged between very fine sand to medium sand and had heterogeneous texture. The coarse grain size percentage increased towards the bottom of the soil. Total heavy metal contents for post-mining bauxite soils are 0,081 ppm, 0,245 to 0,471 ppm and 0,007 ppm for As, Pb and Cd respectively. Heavy metals for Cd, uniformly at every depth from soil level. On the other hand, Pb showed significance pattern, it was indicated every depth from soil level, the concentration of Pb was different.

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Putra, Risandi Dwirama, and Tri Apriadi. "Studi Kontaminasi Logam Berat (Pb dan Cr) Pasca Pertambangan Bauksit Sebagai Potensi Lokasi Kegiatan Budidaya Perikanan." Intek Akuakultur 2, no. 1 (May 11, 2018): 1–15. http://dx.doi.org/10.31629/intek.v2i1.273.

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Bauxite is one of the mining activities, which can lead to the phenomenon of Acid Mine Drainage (AMD). Activities developed by bauxite mining, since the beginning of operations are able to degrade environmental conditions and cause modifications to the main structure of the environment. Alternative to reducing the negative impact of bauxite mining production with re-utilize abandoned bauxite which forms puddles. The puddle of water on bauxite post-mining have potential for Aquaculture. Each sampling site is located in 5 (five) site based on post bauxite mining activities and determine the heavy metal concentraion of Pb and Cr. Soil and sediment samples were collected to analyze the grain size. Total heavy metal concentrations using Atom Flame Absorption Spectrophotometer (AAS). Analysis of heavy metal concentration (Pb dan Cr) with enrichment factor (EF) value of heavy metals Pb indicates extremely high enrichment for post-mining bauxite site at Simpang Dompak, Dompak and Wacopek (EF> 40). Enrichment Factor (EF) Cr on post-mining bauxite post in Simpang Dompak and Sei.Carang site have EF value > 5 indicating this site contamination with Cr. Index Value, Igeo > 5 indicating very strongly contaminated Pb and Cr with Igeo <5 is contaminated moderately. Water quality in Post-mining bauxite shows good condition of water. In general, the post-mining area of bauskit have potential for aquaculture activities although there is high Pb contamination on the substrate but the water quality parameter can utilized for dynamic organisms such as fish. Proper aquaculture techniques to manage the post-mining bauxite in order to be optimally utilized for cultivation activities.

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Hendrik, A. Fauzi, Widiatmaka, D. T. Suryaningtyas, and F. Firdiyono. "Qualitative data envelopment assessment of different alumina refinery plants: the case of bauxite mining in West Kalimantan Province." IOP Conference Series: Earth and Environmental Science 950, no. 1 (January 1, 2022): 012018. http://dx.doi.org/10.1088/1755-1315/950/1/012018.

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Abstract West Kalimantan is a bauxite-rich province with the world’s sixth-largest bauxite reserve. However, Indonesia experienced a bauxite, alumina, and aluminum import vs. export deficit (2018-2020), with imports exceeding exports in value. Based on the calculation of qualitative data envelopment analysis, this case study provides a solution through benchmarking assessment to measure the relative performance of bauxite resource utilization for 12 alumina plants (DEA). This technique utilizes each provincial district’s alumina production plan data to characterize its production technology, which provides a better analysis of how the status of the refinery development plan provides efficiency of alumina refinery plant development according to bauxite allocation across several districts. To determine the benchmarking site, the qualitative DEA method compares the performance analysis of the Charnes, Cooper, and Rhodes (CCR) model for constant return to scale (CRS) and the Banker, Charnes, and Cooper (BCC) model for variable returns to scale (VRS). According to the findings of the scenario I, Kapuas, Kendawangan, and Tayan Hilir are efficient sites. Sungai Kunyit and Cempage Hulu are also benchmarking units in Scenario II. This study aided in the development of a sustainability assessment for the implementation of an alumina refinery development plan across districts in West Kalimantan province.

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Chen, Jun Hong, Bin Li, Hua Sheng Zhan, Jin Dong Su, Ming Wei Yan, and Xiao Ping Li. "Action Mechanism of β-Si3N4 in Bauxite Sintering." Applied Mechanics and Materials 543-547 (March 2014): 3834–38. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.3834.

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In this paper, we added silicon nitride in the samples of common bauxite and the bauxite with high potassium and sodium oxide content, treated them at the high temperature of 1,400°Cand 1,500°C, and then conducted analysis with XRD, SEM and EDS. The results are as follows: After adding β-Si3N4 in sintered bauxite, the partial pressure of oxygen in the composite materials will be reduced, the decomposition and volatilization of compounds with high partial pressure of oxygen (such as potassium oxide and sodium oxide) will be promoted, the content of these compounds in the bauxite will be lowered, and the hazards of the compounds with low melting point will be weakened; meanwhile, with the reduction of potassium, sodium and iron oxide, the lattice of alumina will be activated, the β-Sialon phase will be easily formed and the high temperature properties of sintered bauxite materials will be strengthened.

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de Oliveira, Saulo B., Jeff B. Boisvert, and Clayton V. Deutsch. "Application of Volume Uncertainty for Resource Classification: A Case Study on the Rondon Do Pará Bauxite Deposit, Brazil." Mining 2, no. 4 (October 6, 2022): 670–82. http://dx.doi.org/10.3390/mining2040036.

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This study illustrates the application of conditional simulations to calculate the uncertainty associated with the thickness of bauxite ores. The bauxite deposit of Rondon do Pará in northern Pará State, Brazil, is characterized by a well-defined lateritic profile, with the ore being composed of two sequential horizons: massive bauxite and ferruginous bauxite. This study used ore thickness data from 1.005 drillholes with different grid spacing. Drillhole intervals of both types of bauxite ore were accumulated, converting the database from 3D to 2D. Sequential Gaussian simulation produced probability maps calculated from certain confidence intervals, which permits obtaining the uncertainty associated with estimates in thickness. Results show that in portions with the same regular drillhole spacing there are different ranges of uncertainty and variability, which could be useful to support resource classification, associating different confidence intervals to resource classes. This analysis could also guide the drilling program for resource conversion in order to optimize costs, indicating areas where there is greater uncertainty and would need to be densified. The incorporation of this information into the resource model could be very helpful for supporting subsequent studies of economic evaluation and risk analyses with respect to this type of deposit or similarly in mineral exploration.

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Jiu, Shaowu, Bo Zhao, and Yanxin Chen. "High-Efficiency Desulfurization of High-Sulfur Bauxite Calcined in a Conveyor Bed: Kinetics, Process, and Application." Processes 10, no. 8 (August 12, 2022): 1586. http://dx.doi.org/10.3390/pr10081586.

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The reaction process, mechanism, and kinetics of the desulfurization of high-sulfur bauxite during calcination were investigated using thermal analysis–infrared analysis. A conveyor-bed calcination system was used to study the variations in the physical phase, desulfurization rate, and alumina dissipation rate of high-sulfur bauxite in the range of 500 °C–650 °C. The results show that sclerite monohydrate, kaolinite, rhodochrosite, pyrite, and dolomite mainly decompose during the calcination of high-sulfur bauxite, generating H2O(g), CO2, and SO2 as gaseous products. The decomposition of sclerite monohydrate and kaolinite and the dehydroxylation reactions of rhodochrosite and pyrite occur at <650 °C, with inseparable temperature overlap. High-sulfur bauxite desulfurization follows a three-dimensional spherical diffusion mechanism, with an activation energy of 181.16 kJ/mol, controlled by the diffusion rate of O2 or SO2 through the solid product layer. High-sulfur bauxite was calcined at 600 °C–650 °C for around 3.5 s in a conveyor bed, resulting in a negative divalent sulfur content of <0.03 wt.%, desulfurization rate of >0.98, and relative dissolution rate of alumina of >99%, satisfying the requirements of aluminum extraction via the Bayer method. The desulfurization rate predictions of the kinetic model were consistent with the experimental data.

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Negrão, Leonardo Boiadeiro Ayres, Marcondes Lima da Costa, Herbert Pöllmann, and Axel Horn. "An application of the Rietveld refinement method to the mineralogy of a bauxite-bearing regolith in the Lower Amazon." Mineralogical Magazine 82, no. 2 (February 28, 2018): 413–31. http://dx.doi.org/10.1180/minmag.2017.081.056.

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AbstractA comparison of Rietveld refinement results for a bauxite-bearing regolith and its clayey cover in the Amazon region was made with stoichiometric calculations from chemical analysis and partly from thermogravimetric results. For this investigation a profile in the bauxite-bearing regolith occurrence in the ALCOA bauxite mine at Juruti, Brazil was studied. The different minerals, their compositions and their low crystallinity in the different horizons were investigated and the contents determined. It is evident that some minerals show several generations and some chemical composition changes that must be included in the Rietveld refinement. Al-rich hematites and goethites are common along the bauxite profile. Amorphous contents were determined with rutile added as an internal standard and shown to have gibbsite- or kaolinite-like composition. The minerals could be quantified in the different horizons and the difficulties were mainly related to variable crystalline aspects of the phases. Rietveld refinement can be a powerful tool in bauxite prospecting, quality control and during mining and beneficiation of ore minerals using the adapted refinement strategies.

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Feret, Frank R. "Selected applications of Rietveld-XRD analysis for raw materials of the aluminum industry." Powder Diffraction 28, no. 2 (May 2, 2013): 112–23. http://dx.doi.org/10.1017/s088571561300016x.

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In the last few decades, X-ray diffraction (XRD) systems have been paramount and irreplaceable in controlling bauxite exploration, as well as Bayer and reduction processes. XRD quantitative phase analysis in the aluminum industry witnessed a steady deployment of the Rietveld method, which at present progressively replaces existing methodologies in research and plant laboratories. Rietveld analysis not only helped to surpass traditional XRD calibration methods, it also opened the door for new applications previously not possible. The use of the Rietveld method to characterize selected materials unique to the aluminum industry, such as bauxite, red mud, and alumina is demonstrated and discussed. This paper also presents how synchrotron-based diffractograms obtained for bauxite and red mud samples allowed a much better understanding of mineralogical representation, and made it possible to leverage their Rietveld quantification. Despite clear advantages, the Rietveld method also has limitations that are revealed. For alumina phase quantification, a dedicated Rietveld analytical program was built with structure data for eight alumina mineralogical phases: alpha, beta (β-Al2O3 = Na2O•11Al2O3), delta, gamma (2), kappa, sigma, and theta. The paper gives unique examples of phase quantification in aluminas of various origins and phase composition.

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Zhao, Aichun, Ting-an Zhang, Guozhi Lv, and Wenyan Tian. "Kinetics of the Leaching Process of an Australian Gibbsitic Bauxite by Hydrochloric Acid." Advances in Materials Science and Engineering 2016 (2016): 1–6. http://dx.doi.org/10.1155/2016/5813542.

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Gibbsitic bauxite from Australia was leached by hydrochloric acid in this work. Analysis on kinetics for the extraction of Al2O3was quantitatively studied. It was concluded that the hydrochloric acid leaching process of gibbsitic bauxite was controlled by chemical reaction. Moreover, the mechanism for the dissolution followed the equation,ln⁡k=39.44-1.66×104(1/T), with an apparent activation energy of 137.90 kJ/mol, according to the equation ofk=Ae-Ea/RT. This work aims to provide a good theory support for the process control by using a new method of alumina production from the low grade bauxite.

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Guha, Arindam, Vivek Kr Singh, Reshma Parveen, K. Vinod Kumar, A. T. Jeyaseelan, and E. N. Dhanamjaya Rao. "Analysis of ASTER data for mapping bauxite rich pockets within high altitude lateritic bauxite, Jharkhand, India." International Journal of Applied Earth Observation and Geoinformation 21 (April 2013): 184–94. http://dx.doi.org/10.1016/j.jag.2012.08.003.

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Cui, Tao. "Analysis on Acidity and Alkalinity of Metallogenetic Environment in Penecontemporaneous Period on the Bauxite in WZD Area, Northern Guizhou, China." Advanced Materials Research 989-994 (July 2014): 1428–31. http://dx.doi.org/10.4028/www.scientific.net/amr.989-994.1428.

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Acidity and alkalinity of metallogenetic environment in penecontemporaneous period is very important for the informing of high grade bauxite. Through the research on migration regular of elements, the position of rare earth mineral and the qualitative alternation of bauxite we found that metallogenetic environment is acidic in penecontemporaneous period, from top to bottom of the profile acidity is decreased gradually. In the acidic condition, Si and Fe moved downward but Al is relative enrichment in the middle-upper part of profile.

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Zhang, Shangqing, Fenghua Zhao, Dongna Liu, Lei Zhao, Xiaohui Zhang, Junwei Lin, Haiyu Dong, Shuang Zhao, Xuefei Liu, and Minjie Zan. "Modes of Occurrence of Critical Metal Elements (Li, REEs and Other Critical Elements) in Low-Grade Bauxite from Southern Shanxi Province, China." Minerals 12, no. 8 (August 4, 2022): 990. http://dx.doi.org/10.3390/min12080990.

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The low-grade bauxite in southern Shanxi Province, China is enriched in multiple critical metal elements, including Li, Ga, V, Se, and rare earth elements (REEs), which have reached the standard of comprehensive utilization as independent deposits or associated resources. Even more importantly, identifying the modes of occurrence of these critical elements is essential for designing technologies to extract critical metals from bauxite ores. This study used a combination of direct (X-ray diffraction, scanning electron microscopy–energy dispersive X-ray spectroscopy, and micro-X-ray fluorescence spectrometer), and indirect (size sieving method, float-sink experiment, and correlation analysis) methods to effectively reveal the distribution of critical elements in the different identified mineral phases. The results regarding the low-grade bauxite are as follows: Li was mainly hosted in cookeite as an independent mineral; Ga was mainly associated with diaspore; anatase is the main carrier mineral for V; REEs were present in the low-grade bauxite in multiples modes of occurrence, the most common of which were goyazite, and to a lesser extent, florencite; Se primarily occurs in sulfides. This study contributes to the development and utilization of these essential metal resources in bauxite by providing a useful reference.

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Wu, Jianjun, Shenping Hu, Yongxing Jin, Jiangang Fei, and Shanshan Fu. "Performance Simulation of the Transportation Process Risk of Bauxite Carriers Based on the Markov Chain and Cloud Model." Journal of Marine Science and Engineering 7, no. 4 (April 18, 2019): 108. http://dx.doi.org/10.3390/jmse7040108.

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China imports a large quantity of bauxite each year. Bauxite in fine particles with high moisture has a high risk of liquefaction during the maritime transportation process, which is harmful to the stability and safety of the carrier. To ensure safe shipping, it is necessary to pay attention to the effects of the operation of cargo, the ship’s maneuvering and the ocean environment during the whole transportation process. The simulation of the process risk helps to develop measures to intervene with the cargo behavior to keep the risk to an acceptable level. This study examined the transportation process of a bauxite carrier using the Markov Chain method at different stages of loading, unberthing, departure and sea navigation. Based on the risk transfer matrix of the operational status at different stages of transportation, a cloud simulation model was developed to analyze the transportation process risk of a ship carrying bulk bauxite. Results: the research revealed that the risk evolution rule of the solid bulk cargoes with potential liquefaction during the transportation process, especially bauxite. The risk alteration during the prophase of the transportation process conforms to the rule of the “spoon curve”. Conclusions: a simulation model of the process risk based on the Markov Chain Cloud is suitable for the simulation analysis of the transportation risk of the bulk bauxite carrier. The outcomes of this study may contribute to better safety management to prevent the occurrence of ship capsizing.

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Chen, Yuxin, Baowei Li, Yu Shi, and Shunli Ouyang. "Natural Advantages of Preparation of Composites from Minerals: Effect of Bauxite Addition on the Microstructures and Properties of Fe-Al2O3 Based Composites." Materials 12, no. 9 (May 6, 2019): 1456. http://dx.doi.org/10.3390/ma12091456.

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Fe-Al2O3 composites were prepared by pressureless sintering, using Bayan Obo iron concentrate and bauxite as the main raw materials, activated carbon was added as the reducing agent. The effects of different bauxite additions on the phase composition, microstructures, mechanical properties, and the corrosion-resistance were investigated. The results show that the average grain size of alumina decreased as the bauxite content increased. In addition, bauxite contains TiO2, CaO, and MgO, that can form a liquid phase at high temperature, causing the heat capacity of the micro-zone around the metal phase to be different, which leads to a change of undercooling and further affects the dislocation density of the metal phase. The plastic deformation ability of the metal phase can be improved with the low dislocation density. Fracture mechanism analysis indicated that the metal phase absorbed energy through plastic deformation. The optimum performance of the sample was as follows: the flexural strength was 310 MPa, the hardness 12.14 GPa, the alkali resistance 98.32%, and the acid resistance 95.44%.

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Faulstich, Fabiano Richard Leite, Harlem V. Castro, Luiz Fernando Cappa de Oliveira, and Reiner Neumann. "Raman spectroscopic analysis of real samples: Brazilian bauxite mineralogy." Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 80, no. 1 (October 2011): 102–5. http://dx.doi.org/10.1016/j.saa.2011.03.001.

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Konrad, Florian, Roland Stalder, and Richard Tessadri. "Quantitative phase analysis of lateritic bauxite with NIR-spectroscopy." Minerals Engineering 77 (June 2015): 117–20. http://dx.doi.org/10.1016/j.mineng.2015.03.005.

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Putri, Adinda Ramadhani Haka, Lucas Donny Setijadji, and Dedi Sunjaya. "Potential Enrichment of Scandium in Bauxite Deposit for the Emerging Green Technology Needs." Indonesian Journal of Economic Geology 1, no. 1 (December 30, 2021): 72–84. http://dx.doi.org/10.51835/ijeg.2021.1.1.343.

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Scandium (Sc) becomes one of critical raw materials as principal uses are now in the production of scandium-aluminum alloys and also in Solid Oxide Fuel Cells (SOFCs). Scarcity of scandium resources has led the urgency to discover new potential sources of scandium to meet the supply and demand. One of the possible sources of scandium is from bauxite deposit. Tayan area is part of West Kalimantan laterite belt with the potency for scandium resources in Indonesia as a result of the altered granitoid rocks, namely bauxite. This study presents integrated geological and modes of occurrences study to elucidate the potential enrichment of scandium in the study area including through several laboratory analyses: petrography, XRD, XRF, ICP-MS, and SEM-BSE-EDS. Our study concludes that the concretion textures of bauxite samples are dominated by Fe and Al oxide-hydroxide. The ore is composed of gibbsite and goethite. The result of scandium concentration analysis is equal to 50.9 ppm. Systematic SEM–EDS mapping confirms the presence of scandium as mainly from substitution of Fe3+ and Al3+ by Sc3+. Sc is hosted in goethite, where Sc3+ substitutes Fe3+ in goethite crystal lattice. Sc3+ also substitutes Al3+ in gibbsite crystal lattice. Understanding the enrichment in which scandium occurs in bauxite deposit will hopefully open the new possibility to meet the needs for critical materials for green technology development.

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Lymperopoulou, Theopisti, Paraskevas Georgiou, Lamprini-Areti Tsakanika, Konstantinos Hatzilyberis, and Maria Ochsenkuehn-Petropoulou. "Optimizing Conditions for Scandium Extraction from Bauxite Residue Using Taguchi Methodology." Minerals 9, no. 4 (April 17, 2019): 236. http://dx.doi.org/10.3390/min9040236.

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Bauxite residue is the voluminous by-product of alumina production after Bayer process. Its high alkalinity causes disposal problems and harmful environmental impacts. However, the residue contains significant amounts of valuable elements, such as rare earth elements, including scandium. Greek bauxite residue contains a high amount of scandium close to its main resources. Taking into account scandium’s limited availability coupled with its high demand in modern technology, bauxite residue could be considered as a potential resource for scandium recovery. In this study, the optimization of scandium extraction from bauxite residue with sulfuric acid is investigated using Taguchi methodology. Based on previous studies, acid molarity, leaching time, solid/liquid ratio, and reaction temperature were selected as control parameters for the selective Sc recovery. Method optimization targeted the highest concentration of scandium combined with the lowest concentration of iron without taking into account application constraints. Maximization of scandium concentration can be achieved only by reduced selectivity. The predicted values resulted from the Taguchi methodology were affirmed by a confirmation experiment conducted at optimal conditions. Regression analysis provided the respective equations to be applied on several conditions, depending on different applications.

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Azizah, Diana, Rasoel Hamidy, Mubarak Mubarak, Efriyeldi Efriyeldi, Wahyu Muzammil, Febrianti Lestari, and Sri Murtini. "Index of Mangrove Health Around the Ex-Bauxite Mining Area, Tanjungpinang City, Riau Islands Province." E3S Web of Conferences 324 (2021): 01008. http://dx.doi.org/10.1051/e3sconf/202132401008.

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There are several former bauxite mining areas on Bintan Island which until now have been left open and not managed properly. In Tanjungpinang, the location of the former bauxite mine is located around the mangrove forest ecosystem. The impact of bauxite mining that changes the structure, texture, and physical of the soil can interfere with the development of the root system and the growth of surrounding plants, including mangroves. Therefore, it is necessary to know the health condition of mangroves around the former bauxite mining area. The method used is a cluster plot by calculating the percentage of tree damage based on organ location, type, and level of damage. The results of the analysis show that the health condition of the mangrove forest in Tanjungpinang City is healthy (50,9%); slightly damaged (40,4%) and moderately damaged (8,8%). The locations of the organs that suffered the most damage were roots, lower and upper stems, and leaves. The most common type of damage found roots submerged in red mud; stems and leaves covered with dust and red sand; termite; broken stem; roots break and die; broken shoots; and the leaves change color. The greatest severity is found between 10% and 20%.

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Manivasakan, P., V. Rajendran, P. R. Rauta, B. B. Sahu, and B. K. Panda. "Direct Synthesis of Nano Alumina from Natural Bauxite." Advanced Materials Research 67 (April 2009): 143–48. http://dx.doi.org/10.4028/www.scientific.net/amr.67.143.

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The nano alumina have been synthesised employing a novel eco-friendly route from natural bauxite ore. The synthesis of alumina powder from natural bauxite is of great interest owing to the fact that it enables mass production without the use of expensive chemical resources and processing techniques. Employing the Bayer process, synthesis of nano alumina has been made from natural bauxite followed by sol-gel route. The ultra fine alumina powder with high surface area is obtained through the digestion of gel followed by sintering. The size of the particle and its morphology was controlled by calcination temperature and processing time. The crystallite size of the nano alumina powder has been measured using XRD pattern and the FTIR spectrum of nano powder after calcination at different temperatures (873 K and 1273 K) were measured. The results from the energy dispersive X-ray analysis (EDAX) and morphological studies reveal interesting informations. The observed results indicate that one can control the particle size by controlling the aging and calcination temperature. The obtained results indicate that the above process technique is an unique method for the preparation of nano alumina (Al2O3) from natural source such as bauxite.

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Hui, Ming, Yin Chen Hou, Qing Tian, Xiao Li Shang, and Kai Ping Zhang. "Research of Biological Desilication Mechanism by Bacillus mucilaginosus GSY." Advanced Materials Research 402 (November 2011): 283–87. http://dx.doi.org/10.4028/www.scientific.net/amr.402.283.

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Biological desilication by Bacillus mucilaginosus was investigated using 10 g/L of the cell suspension, fermented liquid and 100 μg/mL of polysaccharide solution. Results showed that the ratio (A/S) of Al and Si in bauxite increased from 2.84 to 3.32, 3.74, 4.19, respectively; and the effects of desilication were all significant by T test. The infrared spectra both of the cell and polysaccharides before and after leaching had significant changes at the wave number of 1070 cm-1 and there were two peaks broadened absorption after leaching, so these appear that the silicon complexes were formed by Si-O-R form. Before and after leaching of bauxite, it was observed by the scanning electron microscope, many holes were formed and the bacteria in the leaching process had significantly erosion on the bauxite surface. Otherwise XREDS analysis further proved that Bacillus mucilaginosus GSY had significant desilication effect.

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Tam, Panias, and Vassiliadou. "Sintering Optimisation and Recovery of Aluminum and Sodium from Greek Bauxite Residue." Minerals 9, no. 10 (September 20, 2019): 571. http://dx.doi.org/10.3390/min9100571.

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Bauxite residue is treated for the recovery of aluminum and sodium by sintering with the addition of soda, metallurgical coke and other reagents such as CaO, MgO and BaO. A thorough thermodynamic analysis using Factsage 7.0™ software was completed together with XRD mineralogy of sinters with different fluxes and reagents additions. Through both thermodynamic interpretation and mineralogical confirmations, it was observed that the type of desilication product in bauxite residue influences the total aluminum recovery through the sintering process and formation of sodium aluminum silicate exists in equilibrium with sodium aluminate, unless silica is consumed by additives (such as CaO, MgO, BaO etc.) forming other more thermodynamically favorable species and liberating alumina. Addition of barium oxide improves the aluminum and sodium recovery to 75% and 94% respectively. Complex sinter product formation that are triggered due to high calcium content in the Greek bauxite residue reduces aluminum recovery efficiency. Optimised and feasible recovery of aluminum and sodium for Greek bauxite residue was proved to be 70% and 85% respectively, when sintered with 50% excess stoichiometric soda. It was observed that stoichiometric carbon addition in inert atmosphere only assisted recovery up to 75% of aluminum and 83% of sodium, though there are benefits gained from pre-reducing iron from hematite for downstream recovery.

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Ostojic, Gordana, Dragica Lazic, and Sasa Zeljkovic. "Determination of silicon dioxide content in bauxite: Comparing the ICP-OES method with the UV-VIS method." Chemical Industry 76, no. 2 (2022): 109–24. http://dx.doi.org/10.2298/hemind211223007o.

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In this paper, the ICP-OES method (induced coupled plasma optical emission spectrometry) was used to determine the content of silicon dioxide in bauxite, as an important impurity that affects the quality and application of bauxite in alumina production by the Bayer process. Twenty bauxite samples from seven different deposits were analysed. The results were compared with the reference spectrophotometric UV-VIS method. The mean relative difference between the silicon dioxide content determined by the ICP-OES method and the reference method is found to be 4.88 %. Statistical tests were used to assess the comparability of the two methods, followed by a scatter plot, the Bland Altman, Passing-Bablok, and the "Mountain" plot. Graphical comparisons generally do not show statistically significant differences between methods. The accuracy and precision of the ICP-OES method were verified by using the standard reference material SRM NIST 697, Dominican Bauxite. Recovery and repeatability values, expressed as relative standard deviation (RSD), are within the acceptance criteria. Based on the t-test, there is a statistically significant difference between the mean value of ICP-OES measurements and the certified value of silicon dioxide, which can be attributed to the effect of systematic error of ICP-OES analysis.

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Ou, Xiaoduo, Shengjin Chen, Jie Jiang, Jinxi Qin, and Zhijie Tan. "Analysis of Engineering Characteristics and Microscopic Mechanism of Red Mud–Bauxite Tailings Mud Foam Light Soil." Materials 15, no. 5 (February 26, 2022): 1782. http://dx.doi.org/10.3390/ma15051782.

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In order to effectively utilize aluminum industrial waste—red mud and bauxite tailings mud—and reduce the adverse impact of waste on the environment and occupation of land resources, a red mud–bauxite tailings mud foam lightweight soil was developed based on the existing research results. Experiments were conducted to investigate the mechanical properties and microscopic characteristics of the developed materials with different proportions of red mud and bauxite tailings mud. Results show that with the increase in red mud content, the wet density and fluidity of the synthetic sample was increased. With 16% red mud content, the water stability coefficient of the synthetic sample reached its maximum of 0.826, as well as the unconfined compressive strength (UCS) of the sample cured for 28 d (1.056 MPa). SEM images reveal that some wastes of the sample without red mud were agglomerated, the peripheral hydration products were less wrapped, and when the amount of red mud was 16%, the hydration products tightly wrapped the waste particles and increased the structural compactness. The final concentration of alkali leaching of samples increased with the addition of red mud. The maximum concentration of alkali leaching was 384 mg/L for the group with the addition of red mud of 16%. Based on the obtained mechanical strength and alkali release analysis, the sample B24R16 was selected as the optimum among all tested groups. This study explored a way to reuse aluminum industrial waste, and the results are expected to be applied to roadbed and mining filling.

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Gasparini, Arthur Stefanelli, Maurício Paulo Ferreira Fontes, Anderson Almeida Pacheco, and João Carlos Ker. "Gibbsite Crystallinity and Morphology in Ferralsols and Bauxites." Minerals 12, no. 11 (November 14, 2022): 1441. http://dx.doi.org/10.3390/min12111441.

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Gibbsite is a common mineral, present in several soil classes around the globe, especially in the tropical belt. It is also a key mineral in bauxite, the main natural source of aluminum. The occurrence of gibbsite in the soil greatly influences its physical and chemical characteristics. However, little is known about the important structural properties of this mineral, which determines how these characteristics will be expressed. In this work, we investigated the variation in the morphology and crystallinity of naturally occurring gibbsites from soils and bauxites. The crystallinity of the gibbsite was assessed using full width at half maximum (FWHM), mean crystallite dimensions (MCD), and deoxydylation temperature (DT) measurements. The results of these analyses were convergent, indicating a better crystallinity for gibbsites from the evaluated Amazon soils and bauxites, and worse crystallinity for the remaining soil samples. SEM analysis was used to assess the gibbsite morphology, and X-ray diffraction data were used to propose an orientation index for this mineral. The results indicated that there is little to no isomorphic substitution of Al by Fe in natural gibbsites, there is a prevalence of larger crystals, with a more laminar morphology, with orientation capability for the gibbsites of Amazon soils and bauxites, and smaller crystals tending to spherical shape for the other samples. These results suggest that natural gibbsite crystals of good crystallinity have large crystals with a laminar shape, while crystals of lower crystallinity present a smaller size and approximately an isodiametric shape.

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Yang, Wu, Min Zhang, Cui Tao, and Jun Yan. "Comprehensive Utilization and Sustainable Development of Bauxite in Northern Guizhou on a Background of Carbon Neutralization." Sustainability 14, no. 21 (November 1, 2022): 14301. http://dx.doi.org/10.3390/su142114301.

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As a developing country, China is also a major producer and consumer of mineral resources. At present, China is still in a critical period of rapid development of industrialization and urbanization, which will inevitably lead to huge resource consumption. It is only 30 years between the peak carbon consumption and the timepoint planned to achieve the goal of carbon neutrality. Coming from a background of dual pressure in terms of the total amount and intensity of “carbon neutrality”, the development and utilization of mineral resources has become one of the important factors in affecting and realizing carbon neutrality in China, and comprehensive utilization has become increasingly important. There are abundant bauxite resources in northern Guizhou, more than 700 million tons, and an industrial resource chain could be built around bauxite. The ore-forming process of bauxite is very complex, and there are enrichment phenomena of other useful elements in the ore-bearing rock series, among which the enrichment of associated Ga, Li and rare earth elements is very obvious. It is of great economic and scientific significance to study the migration law of associated Ga, Li and rare earth elements and to find out whether these elements in bauxite have development value. On the basis of systematically collecting and sorting previous research results, this study carried out supplementary tests on some areas with insufficient data; summarized and studied the migration law of associated Ga, Li and rare earth elements in the Wuzhengdao bauxite deposit in northern Guizhou; and conducted a feasibility analysis on the development and utilization prospects of associated Ga, Li and rare earth elements.

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Terzic, A., V. V. Mitic, Lj Kocic, Z. Radojevic, and S. Pasalic. "Mechanical properties and microstructure fractal analysis of refractory bauxite concrete." Science of Sintering 47, no. 3 (2015): 331–46. http://dx.doi.org/10.2298/sos1503331t.

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The surface topography analysis via fractals as a means of explanation of composite materials mechanical and microstructural characteristics has hardly been reported so far. This study proposes a method of fractal analysis and its application to refractory bauxite concrete surface tribological investigation. Fractal dimension, profilegrams and fast Fourier transform method are introduced and supported by the adequate software for analysing contours and surface roughness, depending on the observation scale and also numerically depending on horizontal lines intercepted by the investigated profile. Also, the Richardson method and Kaye modification are applied to distinguish textured and structured aspect of grain contour geometry. Microstructural investigation was carried out using a scanning electron microscope. Using the fractals of the grains contact surfaces, a reconstruction of microstructure configuration, as grains shapes or inter-granular contacts, has been performed. Obtained results indicated that fractal analyses of contact surfaces of different shapes were very important for the prognosis of the concrete behaviour. The novel approach to the investigation of refractory concrete properties was successfully conducted, as a result introducing fractal identification as a means of composite materials performances evaluation.

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Camara, Issiagha, Jiang Deyi, Oumar Barry, and Frederick Caille. "Bauxite Mining Conflicts in Guinea: Causes Identification, Analysis, and Countermeasures." International Journal of Mineral Processing and Extractive Metallurgy 6, no. 3 (2021): 53. http://dx.doi.org/10.11648/j.ijmpem.20210603.13.

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Kinnarinen, Teemu, Mikko Huhtanen, Lloyd Holliday, and Antti Häkkinen. "Challenges related to solute analysis of bauxite residue filter cakes." Minerals Engineering 120 (May 2018): 1–6. http://dx.doi.org/10.1016/j.mineng.2018.02.001.

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Lewis, Dawn E., John R. White, Denis Wafula, Rana Athar, Tamar Dickerson, Henry N. Williams, and Ashvini Chauhan. "Soil Functional Diversity Analysis of a Bauxite-Mined Restoration Chronosequence." Microbial Ecology 59, no. 4 (December 18, 2009): 710–23. http://dx.doi.org/10.1007/s00248-009-9621-x.

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Journal articles on the topic 'Bauxite Analysis'

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