scholarly journals Sulfuric Acid Baking—Water Leaching for Gold Enrichment and Arsenic Removal from Gold Concentrate

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1332
Author(s):  
Bongju Kim ◽  
Chulhyun Park ◽  
Kanghee Cho ◽  
Jaehyun Kim ◽  
Nagchoul Choi ◽  
...  
Keyword(s):  
Arsenic Removal ◽  
Hot Water ◽  
H2so4 Solution ◽  
Water Leaching ◽  
Leaching Process ◽  
Valuable Metals ◽  
Mineral Compositions ◽  
Gold Grade ◽  
Gold Enrichment ◽  
Leaching Procedure

During the roasting of gold concentrate to improve gold recovery, arsenic is released into the air and valuable elements such as Fe, Cu, Zn, and Pb are converted into oxide minerals. In this research, we evaluated the release of As and the loss of valuable metals during the acid baking and hot water leaching processes used for gold concentrate. The acid bake tests were conducted for gold concentrate using an electric furnace by applying various concentrations of H2SO4 solution under different baking times. The water leaching process was enacted using 70 °C water for the baked samples. Chemical and mineral compositions of the raw and treated samples were analyzed using AAS and XRD, respectively. The results show that soluble metal sulfates, such as rhomboclase and mikasite, were formed in the baked samples, and that the leaching of valuable metals (Fe, Cu, Zn, and Pb) was accelerated during the hot water leaching procedure. During acid baking, arsenic was partially removed by volatilization, and the rest of the arsenic-containing minerals were converted to soluble minerals. The soluble arsenic-containing mineral resulted in a dissolution that was 60 times higher than in the roasted sample. The maximum gold grade of solid residues increased up to 33% through the acid baking–water leaching process. It was confirmed that acid baking with H2SO4 prevented As release into the air, as well as the recovery of valuable metals through hot water leaching, such as Fe, Cu, Zn, and Pb, which were formerly discarded in the tailings.

A Sustainable and Selective Roasting and Water-Leaching Process to Simultaneously Extract Valuable Metals from Low-Grade Ni-Cu Matte

JOM ◽  
2018 ◽  
Vol 70 (10) ◽  
pp. 1977-1984 ◽  
Author(s):  
Fuhui Cui ◽  
Wenning Mu ◽  
Shuai Wang ◽  
Haixia Xin ◽  
Qian Xu ◽  
...  
Keyword(s):  
Low Grade ◽  
Water Leaching ◽  
Leaching Process ◽  
Valuable Metals ◽  
Selective Roasting

scholarly journals Recovery of Gold and Iron from Cyanide Tailings with a Combined Direct Reduction Roasting and Leaching Process

Metals ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 561 ◽  
Author(s):  
Pingfeng Fu ◽  
Zhenyu Li ◽  
Jie Feng ◽  
Zhenzhong Bian
Keyword(s):  
Direct Reduction ◽  
Acid Leaching ◽  
Reduction Temperature ◽  
Reduction Roasting ◽  
Iron Powders ◽  
Leaching Process ◽  
Whole Process ◽  
Iron Phase ◽  
Gold Grade ◽  
Gold Enrichment

Cyanide tailings are the hazardous waste discharged after gold cyanidation leaching. The recovery of gold and iron from cyanide tailings was investigated with a combined direct reduction roasting and leaching process. The effects of reduction temperature, coal dosage and CaO dosage on gold enrichment into Au-Fe alloy (FexAu1−x) were studied in direct reduction roasting. Gold containing iron powders, i.e., Au-Fe alloy, had the gold grade of 8.23 g/t with a recovery of 97.46%. After separating gold and iron in iron powders with sulfuric acid leaching, ferrous sulfate in the leachate was crystallized to prepare FeSO4·7H2O with a yield of 222.42% to cyanide tailings. Gold enriched in acid-leaching residue with gold grade of 216.58 g/t was extracted into pregnant solution. The total gold recovery of the whole process reached as high as 94.23%. The tailings generated in the magnetic separation of roasted products, with a yield of 51.33% to cyanide tailings, had no toxic cyanide any more. The gold enrichment behaviors indicated that higher reduction temperature and larger dosage of coal and CaO could promote the allocation of more gold in iron phase rather than in slag phase. The mechanism for enriching gold from cyanide tailings into iron phase was proposed. This work provided a novel route to simultaneously recover gold and iron from cyanide tailings.

scholarly journals Recovery of Zinc and Silver from Zinc Acid-Leaching Residues with Reduction of Their Environmental Impact Using a Novel Water Leaching-Flotation Process

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 586
Author(s):  
Yunpeng Du ◽  
Xiong Tong ◽  
Xian Xie ◽  
Wenjie Zhang ◽  
Hanxu Yang ◽  
...  
Keyword(s):  
Hazardous Waste ◽  
Acid Leaching ◽  
Copper Recovery ◽  
Water Leaching ◽  
Flotation Process ◽  
Metal Levels ◽  
Valuable Metals ◽  
Leaching Experiments ◽  
Zinc Hydrometallurgy ◽  
Poor Stability

Zinc-leaching residue (ZLR) is a strongly acidic hazardous waste; it has poor stability, high heavy metal levels, and releases toxic elements into the environment. ZLR has potential as a valuable resource, because it contains elevated levels of zinc and silver. In this paper, the recovery of zinc (Zn) and silver (Ag) from ZLR wastes from zinc hydrometallurgy workshops using water leaching followed by flotation was studied. During water leaching experiments, the zinc and copper recovery rates were 38% and 61%, respectively. Thereafter, various flotation testing parameters were optimized and included grinding time, reagent dosages, pulp density, flotation time, and type of adjuster. Experimental results demonstrated this flotation method successfully recycled Ag and Zn. A froth product containing more than 9256.41 g/t Ag and 12.26% Zn was produced from the ZLR with approximately 80.32% Ag and 42.88% Zn recoveries. The toxicity characteristic leaching procedure (TCLP) results indicated the water-leaching flotation process not only recycled valuable metals such as zinc and silver in zinc-containing hazardous wastes but lowered the hazardous waste levels to those of general wastes and recycled wastes in an efficient, economical, and environmentally friendly way.

Recovery of valuable metals from jarosite by sulphuric acid roasting using microwave and water leaching

2016 ◽  
Vol 56 (1) ◽  
pp. 1-9 ◽  
Author(s):  
C. Liu ◽  
S. H. Ju ◽  
L. B. Zhang ◽  
C. Srinivasakannan ◽  
J. H. Peng ◽  
...  
Keyword(s):  
Sulphuric Acid ◽  
Water Leaching ◽  
Valuable Metals

Investigations on a Novel Process to Recycle Valuable Metals from Spent Al2O3-Based Catalyst

2013 ◽  
Vol 634-638 ◽  
pp. 3222-3226
Author(s):  
Yan Hai Shao ◽  
Ming Ming Li ◽  
Xiong Tong
Keyword(s):  
Sodium Aluminate ◽  
Leach Liquor ◽  
Spent Catalyst ◽  
Water Leaching ◽  
Calcination Process ◽  
Aluminate Solution ◽  
X Ray ◽  
Sodium Aluminate Solution ◽  
Valuable Metals ◽  
Leaching Residue

Based on X-ray phase analysis and exploratory experiments, a novel process was proposed to recycle multiple valuable metals like Al, V, Mo, Ni and Co from spent Al2O3-based catalyst. The spent catalyst was roasted by adding sodium carbonate with certain mol ratio, after water leaching, Al, V and Mo could be extracted into leach liquor, whereas Ni and Co were enriched in the leaching residue. V and Mo were precipitated in step from leach liquor by adding CaO and BaAl2O4, respectively. After removal of V and Mo, Al(OH)3 was prepared from sodium aluminate solution with carbonation decomposition process, and the purity of Al2O3 is 99.98%. With sodium bicarbonate leaching-purification-precipitation-calcination process, V2O5 could be prepared from V-bearing residue. Ni and Co were leached from water leaching residue with sulfuric acid. Recoveries of Al, V, Mo, Ni and Co from spent catalyst are 87.0%, 88.7%, 92.1%, 97.8% and 98.6%, respectively.

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