Two-Stage Agitation Leaching of Old Flotation Tailings

2019 ◽  
Vol 298 ◽  
pp. 116-120
Author(s):  
Aleksandr Bulaev ◽  
Vitaliy Melamud ◽  
Anna Boduen

The goal of the present work was to develop hydrometallurgical approaches based on acid leaching for selective extraction of base metals from the sample of old flotation tailings as well as obtaining solution, which can be used for leaching of substandard copper-zinc concentrate. Old flotation tailings contained 23.2% of iron, 0.36% of copper, and 0.23% of zinc. Copper-zinc concentrate contained 23.8% of iron, 16% of copper, and 5.3% of zinc. Agitation leaching of old flotation tailings with distilled water and sulfuric acid solutions (of 0.5 to 10% H2SO4) for 3 h at pulp density of 20% made it possible to extract of 26 to 34% and of 58 to 70% of copper and zinc, respectively. Concentrations of copper and zinc in the pregnant solutions were of 0.19 to 0.25 g/L and of 0.27 to 0.32 g/L, respectively. The increase in H2SO4 concentration up to 10% did not lead to significant increase in base metals extraction but led to significant increase in iron ions concentration in the pregnant solutions. Pregnant solution obtained during the leaching with water contained less than 1 g/L of iron ions, while that obtained during the leaching with 10% sulfuric acid contained about 9 g/L of iron ions. Therefore, two-stage acid leaching with water and 10% sulfuric acid was proposed for selective extraction of non-ferrous metals in the first stage and obtaining of ferric iron solution in the second stage. Two-stage leaching at pulp density of 40% with water made it possible to extract 31 and 64% of copper and zinc, respectively. It was shown, that second stage did not allow to increase non-ferrous metals extraction but made it possible to obtain solution containing 11g/L of ferric iron. This pregnant solution was used for oxidative leaching of copper-zinc concentrate. Leaching at 80°C made it possible to extract 13 and 48% of copper and zinc, respectively.

2020 ◽  
Vol 989 ◽  
pp. 554-558
Author(s):  
Aleksandr Bulaev ◽  
Vitaliy Melamud

The goal of the present work was to develop hydrometallurgical method based on acid leaching, which makes it possible to perform selective extraction of non-ferrous metals from old flotation tailings. Leaching was performed with sulfuric acid solutions (from 0.5 to 10%) and distilled water. Leaching was carried out using percolators and bottle agitator. Percolators were loaded with 100 g of old tailings, and leaching was performed with 100 mL of acid solutions. Pulp density during agitation leaching (S: L) was 1: 5. Two samples of old flotation samples were studied. The first sample of flotation tailings contained 0.26% of copper, 0.22% of zinc, and 17.4% of iron; while the second sample contained 0.36% of copper, 0.23% of zinc, and 23.2% of iron. Percolation leaching made it possible to extract up to 43 and 47% of Cu and Zn from the first sample. Extraction rate was maximum during the leaching with 1 and 2.5% sulfuric acid solutions. During the agitation leaching, the maximum extraction rate was reached with a 2.5% sulfuric acid solution (52 and 54% Cu and Zn), but the leaching rate with all solutions and distilled water differed insignificantly. Percolation leaching made it possible to extract up to 54 and 37% of Cu and Zn from the second sample of tailings, while agitation leaching made it possible to extract up to 34 and 68% Cu and Zn, respectively. The rate of non-ferrous metals extraction from the second sample with water did not differ significantly from that of obtained in the experiments with sulfuric acid solutions. In all experiments, the increase in the H2SO4 concentration led to the increase in concentrations of iron ions in productive solutions, which impedes the extraction of non-ferrous metals from solutions. Thus, it was possible to reach selective leaching of non-ferrous metals and to obtain solutions with relatively low concentrations of iron ions.


Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 376 ◽  
Author(s):  
Qian Zhang ◽  
Qicheng Feng ◽  
Shuming Wen ◽  
Chuanfa Cui ◽  
Junbo Liu

In this work, oxidizing roasting was combined with leaching to separate copper, lead, and zinc from a concentrate obtained by bulk flotation of a low-grade ore sourced from the Jiama mining area of Tibet. The flotation concentrate contained 7.79% Cu, 22.00% Pb, 4.81% Zn, 8.24% S, and 12.15% CaO; copper sulfide accounted for 76.97% of the copper, lead sulfide for 25.55% of the lead, and zinc sulfide for 67.66% of the zinc. After oxidizing roasting of the flotation concentrate, the S content in the roasting slag decreased to 0.22%, indicating that most sulfide in the concentrate was transformed to oxide, which was beneficial to leaching. The calcine was subjected to sulfuric acid leaching for separation of copper, lead, and zinc; i.e., copper and zinc were leached, and lead was retained in the residue. The optimum parameters of the leaching process were: a leaching temperature of 55 °C; sulfuric acid added at 828 kg/t calcine; a liquid:solid ratio of 3:1; and a leaching time of 1.5 h. Under these conditions, the extents of leaching of copper and zinc were 87.43% and 64.38%, respectively. Copper and zinc in the leaching solution could be further separated by electrowinning. The effects of leaching parameters on the extents of leaching of copper and zinc were further revealed by X-ray diffraction and scanning electron microscopy analysis.


2014 ◽  
Vol 633 ◽  
pp. 169-172
Author(s):  
Li Jiao Yang ◽  
Nan Chun Chen ◽  
Xia Ping Zhong ◽  
Jun Gao ◽  
Yao Xiu Lang ◽  
...  

It is found that cuprous sulfite, zinc sulfate and zinc sulfide were the main phases of copper and zinc in zinc leach residue, through analyzing its composition and phase characteristics by XRF and XRD. The method that cooperate sulfuric acid leaching with oxidant was chosen. 60 g/L H2SO4 at 60 °C for 2 h with 4% KMnO4 and liquid/solid ratio of 5..1, 84.29 % of Cu and 92.02 % of Zn are extracted. The ion concentration of copper and zinc are tested by UV-VIS spectrophotometer and EDTA titration respectively. The results show that the amount of acid is sufficient for leaching at the condition of 60 g/L H2SO4 and liquid/solid ratio of 5..1. At the same time, copper change from low valence into high valence after adding KMnO4 which strengthen the leaching, and the chemical reaction can reach balance at 60 °C for 2 h. This method has good extraction effect on copper and zinc.


2021 ◽  
Vol 939 (1) ◽  
pp. 012055
Author(s):  
Kh Otaboev ◽  
D Sherkuziev ◽  
Sh Namazov ◽  
R Radjabov ◽  
A Seytnazarov

Abstract The methods for producing simple superphosphate by two-stage sulfuric acid decomposition of natural phosphates are analyzed. For the first stage, the process of decomposition of high-carbonate powdered phosphorite is studied depending on the rate of sulfuric acid from stoichiometry to the formation of H3PO4, its concentration and the reaction time of the starting components. For the second stage, the process of neutralization of phosphoric acid is studied, depending on the norm of phosphate rock for the formation of Ca(H2PO4)2. The drying process of superphosphate is carried out, in which granular superphosphate is obtained, and P2O5total. - 12%, P2O5free. - 4.6%, P2O5dig : P2O5total = 90%, P2O5 water : P2O5total = 79%.


Metals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1320
Author(s):  
Viet-NhanHoa Nguyen ◽  
Si-Jeong Song ◽  
Man-Seung Lee

Palladium (Pd) electroplating is widely practiced in the manufacture of advanced electronic devices. The Pd(II) present in spent electroplating solutions is treated by cementation with zinc (Zn) metal powder. In order to recover pure Pd from the cemented Pd, a process that consisted of leaching followed by solvent extraction was investigated. For this purpose, solvent extraction experiments using synthesized ionic liquids (ILs) with organic and inorganic anions were performed to find separation conditions at which selective extraction of Pd(II) over Zn(II) from synthetic H2SO4 leaching solutions is possible. The concentration of sulfuric acid was varied from 0.5 to 9 M. The complete separation of Pd(II) over Zn(II) by ILs such as ALi–CY301 (N-methyl-N,N,N-trioctylammonium bis(2,4,4-trimethylpentyl) dithiophosphinic), ALi–SCN (N-methyl-N,N,N-trioctylammonium thiocyanate), ALi–I (N-methyl-N,N,N-trioctylammonium iodide) and ALi–Br (N-methyl-N,N,N-trioctylammonium bromide) depends on H2SO4 concentration, while ALi–LIX63 (N-methyl-N,N,N-trioctylammonium 5,8-diethyl-7-hydroxydodecane-6-oxime) and ALi–LIX84 (N-methyl-N,N,N-trioctylammonium 2-hydroxy-5-nonylacetophenone oxime) can completely separate Pd(II) irrespective of H2SO4 concentration. Additionally, the mixture of HCl and thiourea, aqua regia solution, NH3 solution and the mixture of NH4Cl and NH3 are powerful stripping agents for Pd(II) from the loaded ALi–LIX63/ALi–LIX84, ALi–CY301, ALi–Br/ALi–I and ALi–SCN, respectively. However, application of the separation conditions to the real 5 M sulfuric acid leaching solutions of cemented Pd indicated that it was difficult to separate the two ions by extraction with ALi–LIX63 and ALi–LIX84. Use of NaClO as an oxidizing agent during the sulfuric acid leaching of real cemented Pd resulted in an enhancement of Zn(II) extraction by ALi–LIX63 and ALi–LIX84. Therefore, removal of chloride ions from the sulfuric acid leaching solutions is necessary to apply the separation conditions obtained from synthetic sulfuric acid leaching solutions.


2020 ◽  
Author(s):  
Aleksander Bulaev

The possibility of hydrometallurgical treatment of old flotation tailings to extract base and noble metals was investigated. Two samples of old flotation tailings samples containing 0.26% and 0.36% of copper, and 0.22% and 0.23% of zinc were the subjects of this study. Agitation and percolator leaching was performed with distilled water and sulfuric acid solutions (of 0.5 to 10% H2SO4). It was shown that under certain conditions (sulfuric acid concentration) it was possible to achieve selective leaching of non-ferrous metals and obtain solutions with relatively low concentrations of iron ions, which is necessary for further effective extraction of non-ferrous metal ions from the solution. The effect of acid leaching on further gold recovery from the first sample containing 0.7 g/t of gold by cyanidation was investigated. The sample of the tailings after leaching with a 1% sulfuric acid solution was leached with 10% sulfuric acid. After that, the tailings sample and the acid leach residues were subjected to sorption cyanidation. Two-stage acid leaching with 1 and 10% sulfuric acid provided the higher gold recovery than one-stage (49 and 65%, respectively). Also it was shown that pregnant solution obtained during leaching of the second sample with 10% sulfuric acid may be used for oxidative leaching of substandard copper-zinc concentrate that allowed to 13 and 48% of copper and zinc from the concentrate during the leaching at 80∘C. Keywords: flotation tailings, leaching, substandard sulfide concentrates


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