Journal articles: 'Flocculation and Flotation'

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Luna, Christine Lamenha, Carlos Edison Lopes, and Giulio Massarani. "Recovery of Bacillus sphaericus spores by flocculation/sedimentation and flotation." Brazilian Archives of Biology and Technology 48, spe (June 2005): 61–70. http://dx.doi.org/10.1590/s1516-89132005000400008.

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The aim of this work was use flocculation/sedimentation and flotation for recovery of spores of the Bacillus sphaericus. Microorganism was produced batchwise using culture medium based skimmed milk, corn steep liquor and mineral salts. The best results of flocculation were obtained using CaCl2.2H2O, FeCl3.6H2O, Al2(SO4)3 and tannin as flocculating agents, with optimal flocculation concentrations of 1,500, 3,000, 2,000 and 1,700ppm, respectively. Flocculent suspensions were characterized based on floc diameter and density. Settling tests were performed in batch at different concentrations of the cellular suspensions and revealed high recovery of the solids in suspension in all cases. Flotation tests were accomplished using a mechanical agitated flotation cell and the process was favoured by the increase of the system agitation and for the presence of a cationic collector.

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Ødegaard, H. "Optimization of Flocculation/Flotation in Chemical Wastewater Treatment." Water Science and Technology 19, no. 7 (July 1, 1987): 1233–36. http://dx.doi.org/10.2166/wst.1987.0020.

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An experimental investigation on flocculation/flotation for wastewater treatment was performed. It was demonstrated that flocculation units which are before flotation units in treatment trains must be designed and operated differently to those before sedimentation units. Recommendations regarding design criteria for both flocculation and flotation units are given.

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Ødegaard, Hallvard. "Optimization of flocculation/flotation in chemical wastewater treatment." Water Science and Technology 31, no. 3-4 (February 1, 1995): 73–82. http://dx.doi.org/10.2166/wst.1995.0518.

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An experimental investigation on flocculation/flotation for direct chemical treatment of municipal wastewater was carried out. It was demonstrated that flocculation units prior to flotation must be designed and operated differently to those used prior to sedimentation. Recommendations regarding design criteria both for the flocculation unit and the flotation unit are given.

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Sandbank, E., and G. Shelef. "Harvesting of Algae from High-Rate Ponds by Flocculation-Flotation." Water Science and Technology 19, no. 12 (December 1, 1987): 257–63. http://dx.doi.org/10.2166/wst.1987.0154.

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Microalgae grown in stabilization ponds and in high rate oxidation ponds (HROP) treating wastewater, were harvested by flocculation with aluminium sulfate and floated in a laboratory electro-flotation unit, where bubbles were produced electrolytically. It was shown that the higher the solids concentration, the lower is the air: solids ratio needed to achieve 90% algae removal. The simultaneous flocculation of suspended algae and release of bubbles while flocs grow, give equal suspended solids removal as the classical flush mixing flocculation followed by slow mixing-flotation stage. Air : solidsratios between 0.009 and 0.013 were sufficient for flocs flotation by dissolved air flotation (DAF) and electro flotation. Continuous flocculation-flotation in a DAF pilot plant unit showed that flush mixing can be replaced by injection of chemicals in-line provided a retention of 15 sec is given before the inflow to the flotation tank. Slow mixing could be eliminated altogether when bubbles were generated simultaneously with the flocculation stage. DAF was further simplified, replacing the air compressor used for pressuring air into water by a venturi suction at the under pressure side of the pump in the pressurised line. DAF in its simplified version is preferred for algae harvesting in fresh water algae cultures and in HROP systems, while it is recognized that electroflotation may be preferred in harvesting marine microalgae.

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Liao and Ou. "Flocs Properties and Flotation Performance of Fine Diaspore with Energy Input Pretreatment Induced Using Sodium Oleate." Minerals 9, no. 7 (July 14, 2019): 433. http://dx.doi.org/10.3390/min9070433.

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Energy input, an important factor affecting flocs properties and flotation performance, has rarely been studied in the field of diaspore flotation, which has severely limited our understanding of the flocculation flotation of fine diaspore. Therefore, in this study, the flocs properties and flotation performance of fine diaspore with energy input pretreatment were studied through flotation kinetics, flocs size measurements, and fractal dimension analysis. The results showed that the flocs size increased and the flocs structure became looser with the increasing energy input, while the flocs size decreased and the structure became compact when the energy input exceeded 10.93 kJ/m3. Meanwhile, there were significant differences in the flotation performance under different energy input pretreatment conditions, suggesting that the flotation performance of the fine diaspore was closely related with the flocs properties generated during the agitation process. In particular, the flotation performance was positively correlated with the flocculation degree of flocs, to a certain extent. The flocculation flotation of the fine diaspore benefited from a suitable energy input, and an excessive energy input was not conducive to flotation performance.

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Bunker, Donald Q., James K. Edzwald, Jan Dahlquist, and Lars Gillberg. "Pretreatment considerations for dissolved air flotation: water type, coagulants and flocculation." Water Science and Technology 31, no. 3-4 (February 1, 1995): 63–71. http://dx.doi.org/10.2166/wst.1995.0517.

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Pretreatment considerations of coagulant selection, flocculation time and flocculation mixing intensity were studied for two different water supply types, aquatic humic and non-aquatic humic waters of low turbidity. Alum, ferric salts, and various polyaluminium chlorides (PACs) with different chemical properties were all effective in dissolved air flotation (DAF) when used under favorable conditions of dosage, pH, and flocculation time. A stoichiometry was found for the aluminium coagulants between coagulant dose and raw water DOC. Si and sulfate PACs were effective in treating cold waters with short flocculation times of 2.5 to 5 minutes. Flotation performance improved slightly with increasing flocculation mixing intensity. The results suggest that flocculation tanks be designed to produce strong, “pinpoint” size floc particles.

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Su, Zhenhua, Shujie Fan, Chen Gong, Jianping Ni, Yu Zhang, Bin Yang, Feng Peng, and Mohamed S. Mahmoud. "Incineration Properties and Kinetic Studies of Sludge from Old Newsprint Fiber Line." BioResources 17, no. 2 (April 18, 2022): 3095–106. http://dx.doi.org/10.15376/biores.17.2.3095-3106.

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The basic incineration properties of flotation deinking sludge and two kinds of flocculating sludge from old newsprint fiber line were studied. Coats-Redfern was used for incineration process analysis, and based on the kinetic parameters of the three types of studied sludge at a heating rate of 10 °C·min-1, the reaction orders were confirmed in the organic incineration region. The activation energy of the three sludge types were 38.78, 44.59, and 48.11 kJ·mol-1, and their frequency factors were 2.58 E+07 min-1, 3.19 E+06 min-1, and 1.50 E+06 min-1, respectively. Organics incineration in the flocculation sludge was more difficult than the incineration of the deinking sludge; as the flocculate dosage increased, the incineration difficulty increased. However, the amount of flocculating sludge generated from the flocculation treatment of the deinking white water accounted for less than 10% of the flotation deinking sludge, and their elemental content and calorific value related to combustion were also similar to each other; therefore, it could be predicted that the flocculating sludge would not greatly impact the sludge treatment system. Therefore, it could be incorporated into existing sludge incineration systems for reduction and thermal energy recovery.

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Su, Xing Guo, Yan Jun Li, Jie Liu, Hong Qian Yuan, Ze Honɡ Wanɡ, and Xiao Ge Xu. "Shear Flocculation and Flotation of Hematite." Advanced Materials Research 158 (November 2010): 224–32. http://dx.doi.org/10.4028/www.scientific.net/amr.158.224.

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Sodium alkylsulfonate as collector was used to float hematite by shear flocculation flotation. The effect of the particle size, pulp pH, depressor, shearing strength and shearing time on shear flocculation flotation for hematite was investigated. And the main mechanism of shear flocculation flotation for hematite was analysed and studied by means of interface double layer theory, DLVO and EDLVO theory, shear flocculation theory and basic principles of collision theory. The results show that on the condition of collector usage 4 kg/t, pH of pulp 3, grinding fineness(-0.037mm) 90%, conditioning time 2min, shearing strength 2000r/min and shearing time 7min, the higher iron recovery of 92.4% is obtained. And induced hydrophobic hematite is formed by means of sodium alkylsulfonate and then collision probability of fine hematite is increased to make hydrophobic particles overcome potential barrier and form hydrophobic flocs by direct contact under stirring intensively.

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Stewart, Graham. "Yeast Flocculation—Sedimentation and Flotation." Fermentation 4, no. 2 (April 16, 2018): 28. http://dx.doi.org/10.3390/fermentation4020028.

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da Rosa, Jailton J., and Jorge Rubio. "The FF (flocculation–flotation) process." Minerals Engineering 18, no. 7 (June 2005): 701–7. http://dx.doi.org/10.1016/j.mineng.2004.10.010.

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Xie, Hai Yun, Li Kun Gao, Shu Ming He, Dian Wen Liu, and Xiong Tong. "Flocculation and Sedimentation of Bauxite Flotation Tailings." Applied Mechanics and Materials 260-261 (December 2012): 1179–82. http://dx.doi.org/10.4028/www.scientific.net/amm.260-261.1179.

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Flocculation and sedimentation of fine bauxite from flotation tailing pulp were studied using different flocculants to investigate the possibility of its application. The results of this investigation indicate that inorganic flocculants of PAC and PAS have better flocculating effect than organic flocculants of PAM1# and PAM2# when keeping the original pH (7.5~8.0) of tailing pulp, however its consumption are large. It was found that the pH of pulp is important to the tailings settlement. The dosage of flocculants are greatly reduced and the velocity of floc settling is accelerated when the pH of tailing pulp is adjusted to 6.5~7.0 using sulfuric acid. PAM1# and PAM2# are effective flocculants for fine bauxite from the tailings pulp and improved the sedimentation performance compared with PAC and PAS at pH 6.5~7.0. It was also found that the flocculants can be used in combination to treat original bauxite tailing, and good sedimentation effect has been achieved, but the dosage of reagents is bigger when the organic flocculant is combined with inorganic flocculant.

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Bretas, Pedro Lopes, Otávia Martins Silva Rodrigues, and José Aurélio Medeiros da Luz. "Selective flocculation and floc-flotation of iron bearing mineral slimes." Research, Society and Development 11, no. 5 (April 12, 2022): e45011528289. http://dx.doi.org/10.33448/rsd-v11i5.28289.

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The mineral processing of friable iron ores usually generates ultrafine (smaller than 15 µm) particles, normally called slimes, which usually have a high iron grade and are usually disposed into tailings dam. The traditional mineral process techniques for iron ore do not work efficiently with ultrafines; however, selective flocculation is an alternative to concentrate that fraction. The physical-chemical treatment of iron ore slime was studied here, on a bench scale, based on the scientific foundations of selective flocculation and flotation. Samples of slimes from two Brazilian iron ore processing plants (CEII and VGII) and industrial process waters were used in the tests. Complexometric titration of calcium and magnesium indicated that the process waters were adequate for selective flocculation. Only selective flocculation, even under optimum conditions, did not achieve good results. However, its use prior to flotation led to promising results. The VGII sample has stood out, for which the final concentrate achieved 60.1 % of Fe, the mass recovery was 64.5 % and 13.5 % of Fe in the tailing, resulting selectivity index of 6.58, only with one stage of selective flocculation and one stage of flotation.

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Scriven, R. J., S. K. Ouki, A. S. Doggart, and M. J. Bauer. "The impact of physico-chemical water treatment on a novel flotation/filtration process." Water Science and Technology 39, no. 10-11 (May 1, 1999): 211–15. http://dx.doi.org/10.2166/wst.1999.0658.

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Recent research explored the application of mechanical flocculation ahead of a novel flotation/filtration process (Counter Current Dissolved Air Flotation/Filtration - COCO DAFFTM) and compared it to the process performance seen when hydraulic flocculation was used. The energy input to the system, expressed in terms of the mean velocity gradient, G (s−1), and retention time, t, were used as a guideline for comparison between the two types of flocculation. Generally, better COCO DAFFTM performance resulted from using mechanical flocculation as against that using hydraulic flocculation. High G values (in excess of 80 s−1) were found to give best results, as opposed to values of 30-60 s−1 utilised ahead of conventional treatment. The effect of flocculation contact time on the COCO DAFFTM process was also studied. Current design practice typically utilises 20-30 minutes flocculation contact time. It was found that process performance, in terms of water quality, did not deteriorate excessively if the contact time was reduced to as little as 2 minutes, but filter run times were found to be proportional to contact time.

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Kwak, Dong-Heui, and Mi-Sug Kim. "Flotation of algae for water reuse and biomass production: role of zeta potential and surfactant to separate algal particles." Water Science and Technology 72, no. 5 (June 1, 2015): 762–69. http://dx.doi.org/10.2166/wst.2015.265.

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The effect of chemical coagulation and biological auto-flocculation relative to zeta potential was examined to compare flotation and sedimentation separation processes for algae harvesting. Experiments revealed that microalgae separation is related to auto-flocculation of Anabaena spp. and requires chemical coagulation for the whole period of microalgae cultivation. In addition, microalgae separation characteristics which are associated with surfactants demonstrated optimal microalgae cultivation time and separation efficiency of dissolved CO2 flotation (DCF) as an alternative to dissolved air flotation (DAF). Microalgae were significantly separated in response to anionic surfactant rather than cationic surfactant as a function of bubble size and zeta potential. DAF and DCF both showed slightly efficient flotation; however, application of anionic surfactant was required when using DCF.

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Zou, Xiaotong, Kaiwei Xu, Hao Wen, Yating Xue, Yanhui Qu, and Yanpeng Li. "Efficient microalgae harvesting using a thermal flotation method with response surface methodology." Water Science and Technology 80, no. 3 (August 1, 2019): 426–36. http://dx.doi.org/10.2166/wst.2019.287.

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Abstract Thermal pre-flocculation to enable dispersed air flotation is an economical and ecofriendly technology for harvesting microalgae from water. However, the underlying mechanism and optimal conditions for this method remain unclear. In this study, Chlorella vulgaris (C. vulgaris) and Scenedesmus obliquus (S. obliquus) were harvested using a thermal flotation process. The surface structure and characteristics (morphology, electricity, and hydrophobicity) of the microalgae were analyzed using FT-IR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy), zeta potential, and a hydrophobic test. Further, response surface methodology (RSM) was used to optimize the flotation process. The hydrophobicity of S. obliquus exceeded that of C. vulgaris; as such, under the thermal pre-flocculation, S. obliquus (88.16%) was harvested more efficiently than C. vulgaris (47.16%). Thermal pre-flocculation denatured the lipids, carbohydrate, and proteins of microalgal cell surfaces. This resulted in a decrease in the electrostatic repulsion between the cells and air bubbles. The highest harvesting efficiency was 91.96% at 70 °C, 1,412 rpm, and 13.36 min. The results of this study demonstrate the potential for economic and ecofriendly harvesting of microalgae for biofuels and other bioproducts industries.

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Guo, Jinlong, Yili Wang, Dapeng Li, and Hongxiao Tang. "Counterflow Co-flocculation Flotation for Water Purification." Journal of Environmental Science and Health, Part A 38, no. 5 (May 2003): 923–34. http://dx.doi.org/10.1081/ese-120018601.

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Bogacz, Wojciech, Marcin Lemanowicz, Andrzej Gierczycki, and Anna Mielańczyk. "Flocculation of flotation tailings using thermosensitive polymers." Chemical and Process Engineering 38, no. 3 (September 1, 2017): 379–92. http://dx.doi.org/10.1515/cpe-2017-0029.

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Abstract The key feature of thermosensitive polymers is the reversible transition between the hydrophilic and hydrophopic forms depending on the temperature. Although the main research efforts are focused on their application in different kinds of drug delivery systems, this phenomenon also allows one to precisely control the stability of solid-liquid dispersions. In this paper research on the application of poly(N-isopropylacrylamide) copolymers in processing of minerals is presented. In the experiments tailings from flotation plant of one of the coal mines of Jastrzębska Spółka Węglowa S.A. (Poland) were used. A laser particle sizer Fritsch Analysette 22 was used in order to determine the Particle Size Distribution (PSD). It was proved that there are some substantial issues associated with the application of thermosensitive polymers in industrial practice which may exclude them from the common application. High salinity of suspension altered the value of Lower Critical Solution Temperature (LCST). Moreover, the co-polymers used in research proved to be efficient flocculating agents without any temperature rise. Finally, the dosage needed to achieve steric stabilization of suspension was greatly beyond economic justification.

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Chen, Yanfei, Yuanlin Chen, and Lei Zhang. "Effect of the Molecular Weight of Carboxymethyl Cellulose on the Flotation of Chlorite." Materials 16, no. 9 (April 25, 2023): 3356. http://dx.doi.org/10.3390/ma16093356.

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The present study aimed to investigate the influence mechanism of carboxymethyl cellulose (CMC) on the flotation of fine chlorite. To this end, a series of flotation tests, sedimentation tests, and microscope analyses were conducted. Flotation tests revealed an inverse relationship between particle size and the recovery of chlorite, indicating that finer particles exhibited higher recovery rates. Moreover, it was observed that the recovery of fine chlorite was significantly associated with the water recovery (proportion of water entering the floated product to the weight of water in the initial flotation suspension) and a variety of frother types. Based on these findings, it can be inferred that froth entrainment may constitute a crucial component of the recovery mechanism underlying fine chlorite. Thus, reducing froth entrainment (the phenomenon of hydrophilic minerals entering floated products through foam water) is the key to depress chlorite flotation. Flotation tests indicate that fine chlorite recovered into froth products can be depressed effectively by CMC with a high molecular weight. The results of sedimentation tests and microscope analyses in the presence of CMC prove that CMC with a high molecular weight generates flocculation on fine chlorite particles while that with a low molecular weight does not. It is suggested that the depression of chlorite flotation may be attributed to the reduction in the entrainment resulting from the flocculation induced by CMC.

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Rinne, Tommi, Natalia Araya-Gómez, and Rodrigo Serna-Guerrero. "A Study on the Effect of Particle Size on Li-Ion Battery Recycling via Flotation and Perspectives on Selective Flocculation." Batteries 9, no. 2 (January 17, 2023): 68. http://dx.doi.org/10.3390/batteries9020068.

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The recycling of active materials from Li-ion batteries (LIBs) via froth flotation has gained interest recently. To date, recycled graphite has not been pure enough for direct reuse in LIB manufacturing. The present work studied the effect of particle sizes on the grade of recycled graphite. Furthermore, selective flocculation is proposed as a novel approach to control particle sizes and thus improve graphite grade by preventing the entrainment of cathode components. Zeta potential and particle size measurements were performed to find an optimal pH for electrically selective flocculation and to study the interaction of flocculants, respectively. Batch flotation experiments were performed to investigate the effect of particle size on the purity of the recovered graphite. Results suggested that, in the absence of ultrafine fine particles, battery-grade graphite of 99.4% purity could be recovered. In the presence of ultrafine particles, a grade of 98.2% was observed. Flocculating the ultrafine feed increased the grade to 98.4%, although a drop in recovery was observed. By applying a dispersant in addition to a flocculant, the recovery could be increased while maintaining a 98.4% grade. Branched flocculants provided improved selectivity over linear flocculants. The results suggest that particle size needs to be controlled for battery-grade graphite to be recovered.

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Zhang, Dawei, Yanling Yu, Chao Li, Chunyan Chai, Lili Liu, Jia Liu, and Yujie Feng. "Factors affecting microalgae harvesting efficiencies using electrocoagulation-flotation for lipid extraction." RSC Advances 5, no. 8 (2015): 5795–800. http://dx.doi.org/10.1039/c4ra09983d.

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Bilal, Muhammad, Ilhwan Park, Vothy Hornn, Mayumi Ito, Fawad Ul Hassan, Sanghee Jeon, and Naoki Hiroyoshi. "The Challenges and Prospects of Recovering Fine Copper Sulfides from Tailings Using Different Flotation Techniques: A Review." Minerals 12, no. 5 (May 6, 2022): 586. http://dx.doi.org/10.3390/min12050586.

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Flotation is a common mineral processing method used to upgrade copper sulfide ores; in this method, copper sulfide mineral particles are concentrated in froth, and associated gangue minerals are separated as tailings. However, a significant amount of copper is lost into tailings during the processing; therefore, tailings can be considered secondary resources or future deposits of copper. Particle–bubble collision efficiency and particle–bubble aggregate stability determines the recovery of target particles; this attachment efficiency plays a vital role in the selectivity process. The presence of fine particles in the flotation circuit is because of excessive grinding, which is to achieve a higher degree of liberation. Complex sulfide ores of markedly low grade further necessitate excessive grinding to achieve the maximum degree of liberation. In the flotation process, fine particles due to their small mass and momentum are unable to collide with rising bubbles, and their rate of flotation is very slow, further lowering the recovery of target minerals. This collision efficiency mainly depends on the particle–bubble size ratio and the concentration of particles present in the pulp. To overcome this problem and to maintain a favorable particle–bubble size ratio, different techniques have been employed by researchers to enhance particle–bubble collision efficiency either by increasing particle size or by decreasing bubble size. In this article, the mechanism of tailing loss is discussed in detail. In addition, flotation methods for fine particles recovery such as microbubble flotation, column flotation, nanobubble flotation, polymer flocculation, shear flocculation, oil agglomeration, and carrier flotation are reviewed, and their applications and limitations are discussed in detail.

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Niu, Fusheng, Yuying Chen, Jinxia Zhang, and Zhenjia Chang. "High-Speed Dynamic Camera Analysis of the Hematite Floc–Bubble Mineralization Process." Minerals 13, no. 7 (July 20, 2023): 964. http://dx.doi.org/10.3390/min13070964.

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The most efficient method for recovering microfine-grained hematite ore is flocculation flotation. Because the flocculation–bubble mineralization process in flocculation flotation has yet to be well investigated, a series of experimental investigations on hematite flocculation–bubble were conducted to better understand the hematite flocculation–bubble interaction process. The results show that as the flocculant size increases, the sliding time of the flocculant to the bottom of the bubble shortens, and the change in the instantaneous dynamic velocity is slower when the diameter of the fixed bead is 544.52 μm, which is more favorable to flocculant adhesion on the bubble surface. When the bubble diameter is 544.52 μm and the floc diameter is 39.65 μm, the shortest time is 49.5 ms, and the maximum value of instantaneous velocity is 28.67 μm·ms−1. According to the force analysis of the floc on the bubble surface, when the particle size of the floc is 39.65 μm and the bubble diameter is 544.52 μm, the desorption force is 4.99 × 10−3 mN·m−1 larger, and the adhesion force is 7.08 × 10−4 mN·m−1 smaller. The smaller Bond constant Bo′ is 0.14. In that moment, the flocs in the sodium solution are very stable.

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Demir, Irem, Alexandre Besson, Pascal Guiraud, and Cécile Formosa-Dague. "Towards a better understanding of microalgae natural flocculation mechanisms to enhance flotation harvesting efficiency." Water Science and Technology 82, no. 6 (April 15, 2020): 1009–24. http://dx.doi.org/10.2166/wst.2020.177.

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Abstract In microalgae harvesting, flocculation is usually a compulsory preliminary step to further separation by sedimentation or flotation. For some microalgae species, and under certain growth conditions, flocculation can occur naturally. Natural flocculation presents many advantages as it does not require the addition of any flocculants to the culture medium and shows high efficiency rate. But because natural flocculation is so specific to the species and conditions, and thanks to the knowledge accumulated over the last years on flocculation mechanisms, researchers have developed strategies to induce this natural harvesting. In this review, we first decipher at the molecular scale the underlying mechanisms of natural flocculation and illustrate them by selected studies from the literature. Then we describe the developed strategies to induce natural flocculation that include the use of biopolymers, chemically modified or not, or involve mixed species cultures. But all these strategies need the addition of external compounds or microorganism which can present some issues. Thus alternative directions to completely eliminate the need for an external molecule, through genetic engineering of microalgae strains, are presented and discussed in the third part of this review.

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Amato, T., J. K. Edzwald, J. E. Tobiason, J. Dahlquist, and T. Hedberg. "An integrated approach to dissolved air flotation." Water Science and Technology 43, no. 8 (April 1, 2001): 19–26. http://dx.doi.org/10.2166/wst.2001.0455.

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DAFRapide® techniques utilising reduced flocculation times, of the order of 5 minutes, together with flotation loading rates of up to 40 m/h, can be incorporated with conventional filtration systems operating at up to 20 m/h. Product quality of typically <1 NTU and <0.1 NTU after flotation and filtration respectively can be achieved.

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Liu, J. C., and C. S. Lien. "Pretreatment of bakery wastewater by coagulation-flocculation and dissolved air flotation." Water Science and Technology 43, no. 8 (April 1, 2001): 131–37. http://dx.doi.org/10.2166/wst.2001.0482.

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The pretreatment of wastewater from a large-scale bakery was studied. In the coagulation-flocculation reaction, it was found that both alum and FeCl3 were effective in the jar tests. When at coagulant dosage of 90 to 100 mg/l, 55 % of COD and 95 to 100% of SS could be removed. The optimum pH was at 6.0. In addition, the removal of SS was affected by pH more significantly, while the removal of COD was not affected in the pH range of 6.0 to 8.0. In the DAF experiments, 48.6% of COD and 69.8% of SS were removed in 10 min at a pressure of 4 kg/cm2, recycle ratio of 0.3 l/min, and pH of 6.0. Upon the addition of 100 mg/l of alum, the removal efficiency of COD did not increase while SS removal increased to 82.1%. It was found that 5-min flocculation time did improve the COD removal while it had little effect on SS removal. Flocculation for longer than 5 min did not enhance the flotation performance. Similar phenomena were observed when FeCl3 was used as the coagulant, except that flocculation had an insignificant effect on COD and SS removal. It was also found that FeCl3 was relatively more effective than alum. In summary, both coagulation-flocculation and DAF were efficient for the pretreatment. The advantages and disadvantages were discussed.

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YANG, BINGQIAO, and SHAOXIAN SONG. "HYDROPHOBIC AGGLOMERATION OF MINERAL FINES IN AQUEOUS SUSPENSIONS AND ITS APPLICATION IN FLOTATION: A REVIEW." Surface Review and Letters 21, no. 03 (June 2014): 1430003. http://dx.doi.org/10.1142/s0218625x14300032.

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Hydrophobic agglomeration is originated from the hydrophobic attraction between particles, which is essentially different from electrolyte coagulation and polymer flocculation. It is applied to mineral processing in floc-flotation process to improve the recovery of mineral fines. In this paper, the applications of this phenomenon in mineral fines were summarized, including the origin of hydrophobic agglomeration, the main factors affect hydrophobic agglomeration (particle hydrophobicity, shear rate and duration, nonpolar oil and tank geometry), as well as hydrophobic agglomeration based separation processes (carrier flotation and floc-flotation).

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Officer, J., J. A. Ostrowski, and P. J. Woollard. "The design and operation of conventional and novel flotation systems on a number of impounded water types." Water Supply 1, no. 1 (January 1, 2001): 63–69. http://dx.doi.org/10.2166/ws.2001.0008.

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This paper describes the design of conventional Dissolved Air Flotation (DAF) systems, and the novel Counter Current Dissolved Air Flotation Filtration (COCODAFF®) process. The operation and performance of these plants on a variety of water types in the United Kingdom and South Africa is also described. The advantages of flotation processes for the treatment of impounded waters either high in colour, or with a high concentration of algae, is discussed. Other topics covered in this paper are hydraulic flocculation, and the application of Finite Element Analysis (FEA), to the design of flotation plants. It is concluded that the COCODAFF® process offers a number of advantages over conventional DAF systems.

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Ødegaard, H. "The use of dissolved air flotation in municipal wastewater treatment." Water Science and Technology 43, no. 8 (April 1, 2001): 75–81. http://dx.doi.org/10.2166/wst.2001.0468.

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Flotation can be used in municipal wastewater treatment plants in different ways. Since the pollutants in wastewater to such a large extent are associated with particles, a very substantial treatment efficiency can be reached at a very small space, by using flotation in a chemical (or enhanced primary) treatment scheme. This is demonstrated in this paper with reference to results from small, prefabricated chemical plants based on flotation, which are frequently used in Norway. If used in connection with biological plants (for instance for nitrogen removal), the combination of biofilm reactors and flotation is especially advantageous because coagulation/flocculation/flotation can be placed directly after the bioreactor. Results from two such plants in Norway are presented. Recommendations with respect to design and operation of flotation plants in wastewater treatment are given.

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Matter, Bui, Jung, Seo, Kim, Lee, and Oh. "Flocculation Harvesting Techniques for Microalgae: A Review." Applied Sciences 9, no. 15 (July 29, 2019): 3069. http://dx.doi.org/10.3390/app9153069.

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Microalgae have been considered as one of the most promising biomass feedstocks for various industrial applications such as biofuels, animal/aquaculture feeds, food supplements, nutraceuticals, and pharmaceuticals. Several biotechnological challenges associated with algae cultivation, including the small size and negative surface charge of algal cells as well as the dilution of its cultures, need to be circumvented, which increases the cost and labor. Therefore, efficient biomass recovery or harvesting of diverse algal species represents a critical bottleneck for large-scale algal biorefinery process. Among different algae harvesting techniques (e.g., centrifugation, gravity sedimentation, screening, filtration, and air flotation), the flocculation-based processes have acquired much attention due to their promising efficiency and scalability. This review covers the basics and recent research trends of various flocculation techniques, such as auto-flocculation, bio-flocculation, chemical flocculation, particle-based flocculation, and electrochemical flocculation, and also discusses their advantages and disadvantages. The challenges and prospects for the development of eco-friendly and economical algae harvesting processes have also been outlined here.

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30

Edzwald, James K., John P. Walsh, Gary S. Kaminski, and Howard J. Dunn. "Flocculation and Air Requirements for Dissolved Air Flotation." Journal - American Water Works Association 84, no. 3 (March 1992): 92–100. http://dx.doi.org/10.1002/j.1551-8833.1992.tb07325.x.

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31

Laamanen, Corey A., Gerusa N. A. Senhorinho, Gregory M. Ross, and John A. Scott. "Heat-aided flocculation for flotation harvesting of microalgae." Algal Research 20 (December 2016): 213–17. http://dx.doi.org/10.1016/j.algal.2016.10.019.

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32

Molaei, Nahid, Mohammad Shoaib, John Forster, Shaihroz Khan, Omar Bashir Wani, and Erin R. Bobicki. "Surface interaction between phyllosilicate particles and sustainable polymers in flotation and flocculation." RSC Advances 12, no. 6 (2022): 3708–15. http://dx.doi.org/10.1039/d1ra07928j.

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Biopolymers with different backbones have the potential to disperse the phyllosilicate particles in flotation or release the water trapped within tailing particles in flocculation and could decrease environmental problems of conventional reagents.

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33

Vlaški, A., A. N. van Breemen, and G. J. Alaerts. "The role of particle size and density in dissolved air flotation and sedimentation." Water Science and Technology 36, no. 4 (August 1, 1997): 177–89. http://dx.doi.org/10.2166/wst.1997.0114.

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Conventional (sedimentation) and advanced (dissolved air flotation) treatment were studied in the context of removal of the single cells form of the cyanobacteria Microcystis aeruginosa. This cyanobacterium species is recognised as an ideal surrogate for process removal efficiency assessment of particles of the problematic size range (3-10 m). The agglomeration (coagulation/flocculation) phase has been indicated as essential and determining the down-stream process efficiency, hence it is a prerequisite for process improvement. Relevant process parameters have been addressed on a laboratory (model water) and pilot plant (reservoir water) scale, including the influence of coagulant (FeCl3) dose, coagulation pH, flocculation time, energy input (G value), single stage versus tapered flocculation and application of cationic polymer as coagulant aid. The process efficiency was assessed as a function of the preceeding agglomeration (coagulation/flocculation) phase and the obtained particle (floc) size distributions. The particle (floc) size - density relationship was addressed in the context of more accurate process kinetic modelling.

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34

Wang, Yu Heng, Sheng Guang Zhuo, Yi Xin Yang, and Na Li. "Application of Chitosan in Removing Algae by Dissolved Air Flotation." Advanced Materials Research 347-353 (October 2011): 1911–16. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.1911.

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Using polyaluminium chloride (PAC) and chitosan as the main coagulant and coagulant-aid respectively, the high algae-laden water was treated by coagulation/flocculation/dissolved air flotation (C/F/DAF). When the doses of PAC and chitosan were both moderate (7.0~8.4 mg Al2O3/L of PAC and 0.6~1.0 mg/L of chitosan), the removal rates of turbidity, algae cells and TOC were all increased apparently compared with adding PAC alone. Especially, the residual aluminum concentration reduced significantly in treated water with the aid of chitosan. The structrue and strength of flocs formed by coagulation aid of chitosan were improved obviously, which proved that addition of chitosan could enhance the flocculation performance of PAC. So, in C/F/DAF process for removing algae, using chitosan as coagulant-aid can improve the flotation performance and reduce residual aluminum concentration in treated water.

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35

Jin, Saizhen, and Leming Ou. "Comparison of the Effects of Sodium Oleate and Benzohydroxamic Acid on Fine Scheelite and Cassiterite Hydrophobic Flocculation." Minerals 12, no. 6 (May 29, 2022): 687. http://dx.doi.org/10.3390/min12060687.

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Sodium oleate (NaOL) and benzohydroxamic acid (BHA) are commonly used scheelite and cassiterite flotation collectors. Hydrophobic flocculation flotation of fine minerals has been extensively studied and reported under a NaOL system, but not under a BHA system. In this paper, the particle size distribution and flotation behaviour of fine scheelite (−10 μm) and cassiterite (−37 + 10 and −23 μm) after shear stirring in NaOL, BHA, and Pb2+ + BHA systems were studied by laser particle size analysis and flotation tests. The measured particle size distribution results revealed that the fine minerals could aggregate under a NaOL system, and the aggregate size increased with increasing stirring time and speed, with scheelite aggregating faster than cassiterite. BHA did not cause scheelite or cassiterite to form hydrophobic aggregates. At low stirrer speeds, the minerals could form small, weak, and easily broken aggregates when Pb2+ + BHA was added. The results of the flotation tests revealed that increasing the stirring time and speed increased the flotation rate and recovery when NaOL and BHA were added. When Pb2+ + BHA was added, however, the changes in flotation rate and recovery were not noticeable when the stirring conditions were changed.

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Deka, Bhaskar Jyoti, Jiaxin Guo, Sanghyun Jeong, Manish Kumar, and Alicia Kyoungjin An. "Emerging investigator series: control of membrane fouling by dissolved algal organic matter using pre-oxidation with coagulation as seawater pretreatment." Environmental Science: Water Research & Technology 6, no. 4 (2020): 935–44. http://dx.doi.org/10.1039/c9ew00955h.

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High AOM removal achieved by pre-oxidation with coagulation–flocculation-dissolved air flotation. In situ ferrate was formed by wet chemical oxidation of NaOCl-Fe³⁺. Membrane fouling was significantly alleviated and assessed by OCT technique.

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37

Ming, Pingtian, Dan Zou, Fei Li, Qingqing Xing, and Zhen Wang. "Sedimentation of Fine Arsenopyrite with PEI and the Flotation Significance." Minerals 12, no. 7 (June 28, 2022): 824. http://dx.doi.org/10.3390/min12070824.

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The flotation of fine mineral particles is always a difficult problem. The flotation of fine arsenopyrite particles (−20 μm) in a sodium butyl xanthate (SBX) system was studied by using polyethyleneimine (PEI) as a flocculant. The flocculation properties of PEI on fine arsenopyrite were studied using sedimentation tests. The results showed that the optimum pH for the sedimentation of PEI was approximately 7.5; the higher the molecular weight (M.W.) of the flocculant, the better the sedimentation effect. In the flotation experiments, it was found that the flotation recovery of PEI-3 with high M.W. as flocculant was only 57%, while the flotation recovery of PEI-2 with medium M.W. was 90% under respective optimum conditions. The contact angle tests showed that the natural contact angle of arsenopyrite was 37°; the addition of moderate PEI-2 had a slightly negative influence on the hydrophobicity of arsenopyrite in the SBX system. From the size analysis results, the maximum particle size (D100) and median size (D50) of the arsenopyrite increased from 20 and 11 μm to 48 and 28 μm after treatment with 40 mg/L PEI-2, a size more conducive to bubble capture. From the combination of these results, it can be concluded that PEI-2 improved the flotation of fine arsenopyrite mainly by increasing the particle size to a suitable range through flocculation. The XPS results indicated that the adsorption of PEI-2 on the arsenopyrite surface was due to the chemisorption between the imino group and the active Fe/As sites. Applying PEI-2 to a fine disseminated arsenopyrite-type gold ore, a concentrate containing 36 g/t Au with a Au recovery of 88% can be obtained.

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38

Niu, Fu Sheng, Shu Xian Liu, Jin Xia Zhang, and Yi Miao Nie. "Study on Dispersion Behaviors of Oolitic Hematite Ultrafine Particles in Water." Advanced Materials Research 383-390 (November 2011): 3169–73. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.3169.

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The fine oolitic hematite ore (＜20μm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent use level. In this article, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

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39

Niu, Fu Sheng, Chen Miao, and Jin Xia Zhang. "Selective Flocculation of Fine Grain Oolitic Hematite Behavior Research." Applied Mechanics and Materials 303-306 (February 2013): 2537–40. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.2537.

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The fine oolitic hematite ore (<20µm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent dosage. In this paper, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

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40

Li, Feng Jiu. "Study on Dispersion Character of Fine Oolitic Hematite Ore Particle." Applied Mechanics and Materials 50-51 (February 2011): 924–28. http://dx.doi.org/10.4028/www.scientific.net/amm.50-51.924.

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The fine oolitic hematite ore (＜20μm) is easily covered by the ore slime, therefore, it is processed very difficultly with traditional crafts, for example, gravity treatment, magnetic separation, and flotation. The tiny iron ore is unable to recycle effectively, bring about a large of useful minerals running off. It is indicated that the selective flocculation is effective separation craft in many research works. The good dispersion of fine particles is the selective flocculation essential condition, the excessive dispersion will destroy the selective flocculation, at the same time it can be influenced by the water quality, pH, the mixing time, the shear rate and the dispersing agent use level. In this article, to oolitic hematite ore, the chemistry dispersion research is conducted to provide the foundation for further selective flocculation separation.

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41

Akdemir, Ü. "Shear flocculation of fine hematite particles and correlation between flocculation, flotation and contact angle." Powder Technology 94, no. 1 (November 1997): 1–4. http://dx.doi.org/10.1016/s0032-5910(97)03216-6.

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42

Deng, Xiao Gang, and Xian Ming Zhang. "The Kinematics Mathematical Model of the Impulse Electro Flotation." Advanced Materials Research 403-408 (November 2011): 2936–40. http://dx.doi.org/10.4028/www.scientific.net/amr.403-408.2936.

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Through the characteristics of the Impulse electro flotation Wastewater treatment equipment, the factors which affect the efficiency of this technology are analyzed. According to the Kinematical theory of flocculation process, the free particle flotation removal model is established used in the way how the steel ball model is simplified. , and the variable process of the concentration of the free particle along with the time is stimulated to be obtained. This mathematical model has the theoretical reason of how to choose the electric flotation parameters and design of the electric flotation treatment equipments. The result proves that when the treatment time is between 20 to 25 min., the removal rate of the free particles will achieve to above 90%, which is similar to the experiment data.

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43

Bernard, C., P. Herviou, and T. Poujol. "Stormwater treatment by dissolved air flotation: first results from a pilot project." Water Science and Technology 32, no. 1 (July 1, 1995): 137–43. http://dx.doi.org/10.2166/wst.1995.0031.

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A stormwater treatment plant using dissolved air flotation was operated in 1993, at the outlet of the Chelles River catchment area (Seine-et-Marne, France). The process was divided into two different stages. Firstly, a coagulation/flocculation stage, secondly a flotation stage in a flotation tank. The flow rate was set at 13 m3/h. Stormwater was the main part of the effluent but with some urban wastewater as the network is not strictly separate. The process efficiency was tested for suspended solids, chemical oxygen demand and hydrocarbons. A total hydrocarbon removal was observed. Finally, constant output concentrations were observed in spite of important input roughwater concentration variations.

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Long, Huang, and Xiao. "The Effect of Surface Charge on the Separation of Pyrite from Serpentine by Flotation." Minerals 9, no. 10 (October 14, 2019): 629. http://dx.doi.org/10.3390/min9100629.

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Serpentine, a magnesium silicate mineral with positive surface charge in many sulfide ores around the world, usually deteriorates the flotation behavior by covering the target mineral surface. In this paper, the effect of surface potential regulation on serpentine flotation was revealed by flocculation experiments, zeta potential measurements, infrared spectrum analysis, and DLVO theoretical calculations. The experimental results of flocculation and sedimentation show that heterogeneous coagulation easily occurs between serpentine and pyrite particles, which reduces the floatability of pyrite. Reducing the surface potential of serpentine is an effective way to eliminate heterogeneous coagulation between minerals. The key to regulating the surface potential of serpentine is Mg2+ ion dissolution from the serpentine surface to the liquid phase. Phosphates, especially sodium hexametaphosphate, can enhance Mg2+ ion dissolution from the serpentine surface to the liquid phase and react with Mg2+ ions in the liquid phase to form stable soluble complexes.

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45

Bonneville, C., and D. W. Smith. "Effects of pre-ozonation and selected advanced water treatment processes on Mount Seymour impoundment water." Water Supply 1, no. 2 (March 1, 2001): 83–90. http://dx.doi.org/10.2166/ws.2001.0024.

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In May 1999, a project using a dissolved air flotation (DAF)/ozone/filtration pilot plant was started to study the effects of pre-ozonation on the flocculation of particles and removal of organic matter in an advanced treatment process. Results indicate that small doses of ozone pre-ozonation slightly improve the flocculation of particles and their subsequent removal in the DAF unit when used in conjunction with alum or PACl. However, it was found that high ozone doses impeded flocculation. More significant is ozone's benefit for the removal of UV-absorbing organic matter. The study also found that DAF is very effective at removing turbidity causing particles and colour from the water, thereby improving filter performance.

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46

Pouet, M. F., and A. Grasmick. "Urban wastewater treatment by electrocoagulation and flotation." Water Science and Technology 31, no. 3-4 (February 1, 1995): 275–83. http://dx.doi.org/10.2166/wst.1995.0536.

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In waste water treatment, the use of a physico-chemical process by flotation would present some advantages compared to a separation by settling. However like each physico-chemical process, a separation by flotation needs a chemical destabilization. We have studied the use of an electrochemical destabilization coupled to a process of flotation (DAF). This paper presents the results obtained on an urban waste water treated by electrocoagulation and dissolved air flotation (DAF). To show the interest of coupling flotation and electrocoagulation, we have studied each process separately. Then we have combined the two processes. The role of each operation on pollution removal is presented. An effect of synergism between the two processes on the pollution abatement is shown. A reduction of 75% of the global COD is obtained. The results of the coupling are compared to the performance of an intensive treatment by flocculation-lamellar settler.

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47

Knezevic, Dinko, Laslo Caki, Dragana Nisic, and Branislav Mikovic. "Impact of flocculation on flotation tailing's hydro-cycloning properties." Tehnika 69, no. 6 (2014): 945–51. http://dx.doi.org/10.5937/tehnika1406945k.

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48

Colic, Miroslav, Domagoj Gotovac, and Ariel Lechter. "Flocculation-Flotation vs. MBR for High MLSS Secondary Clarification." Proceedings of the Water Environment Federation 2014, no. 13 (October 1, 2014): 1568–80. http://dx.doi.org/10.2175/193864714815939813.

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49

Pascoe, R. D., and E. Doherty. "Shear flocculation and flotation of hematite using sodium oleate." International Journal of Mineral Processing 51, no. 1-4 (October 1997): 269–82. http://dx.doi.org/10.1016/s0301-7516(97)00033-1.

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50

Patra, Partha, and K. A. Natarajan. "Microbially induced flotation and flocculation of pyrite and sphalerite." Colloids and Surfaces B: Biointerfaces 36, no. 2 (July 2004): 91–99. http://dx.doi.org/10.1016/j.colsurfb.2004.05.010.

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Journal articles on the topic 'Flocculation and Flotation'

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