scholarly journals Hydrometallurgical Processing of the Wastes of Polymetallic Ore Dressing

2020 ◽  
Author(s):  
Aleksander Bulaev
Keyword(s):  
Sulfuric Acid ◽  
Noble Metals ◽  
Ferrous Metal ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Gold Recovery ◽  
Flotation Tailings ◽  
Hydrometallurgical Processing ◽  
Two Samples ◽  
Sulfide Concentrates

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

Uranium Bioleaching from Low Grade Ore

2020 ◽  
Vol 989 ◽  
pp. 559-563
Author(s):  
Ashimkhan T. Kanayev ◽  
Khussain Valiyev ◽  
Aleksandr Bulaev
Keyword(s):  
Sulfuric Acid ◽  
Acid Mine Drainage ◽  
Mine Drainage ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Leach Solution ◽  
Low Grade ◽  
Bacterial Cells ◽  
Acid Mine

The goal of the present work was to perform bioleaching of uranium from low grade ore from Vostok deposit (Republic of Kazakhstan), which was previously subjected to long-term acid leaching. The ore initially contained from 0.15 to 0.20% of uranium in the form of uraninite, but ore samples used in the study contained about 0.05% of uranium, as it was exhausted during acid leaching, and uranium was partially leached. Representative samples of ore were processed in 1 m columns, leach solutions containing 5, 10, 20 g/L of sulfuric acid and bacterial cells (about 104) were percolated through the ore. Leaching was performed at ambient temperature for 70 days. In one of the percolators, the leaching was performed with leaching solution containing 10 g/L of H2SO4, cells of A. ferrooxidans, and 0.5 g/L of formaldehyde. Leaching with the solution containing 5, 10, and 20 g/L of sulfuric acid made it possible to extract 50, 53, and 58% of uranium. Addition of formaldehyde in leach solution led to the decrease in uranium extraction extent down to 37%. Thus, the results of the present work demonstrated that uranium ore exhausted during long-term acid leaching may be successfully subjected to bioleaching, that allows extracting residual quantities of uranium. Leaching rate of uranium from exhausted ore depended on both sulfuric acid concentration and microbial activity of bacteria isolated from acid mine drainage, formed on uranium deposit. In the same time, acid mine drainage may be used as a source of inoculate, to start bioleaching process.

Study on Recovering Zinc from Gossan

2012 ◽  
Vol 454 ◽  
pp. 329-332 ◽  
Author(s):  
Jin Lin Yang ◽  
Shao Jian Ma ◽  
Wei Mo ◽  
Jin Peng Feng ◽  
Xiu Juan Su ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Leaching Rate ◽  
Sulfuric Acid Leaching ◽  
Alkaline Leaching ◽  
Physical Separation ◽  
Xrd Pattern ◽  
Diffraction Peaks ◽  
Roasting Temperature

In this paper, the conventional physical separation method such as flotation, gravity separation, magnetic separation, alkaline leaching and sulfuric acid leaching were studied. The effects of grinding fineness, amount of agent, magnetic intensity, roasting temperature, roasting time, the leaching agent and leaching time on the leaching of zinc were investigated, respectively. The results show that the leaching rate of zinc is below 50% in the conventional alkaline leaching, and the leaching rate of zinc is below 85% and the leaching rate of iron is above 35% in sulfuric acid leaching. Compared with XRD pattern of the raw ore, the different diffraction peaks of smithsonite is off in alkaline leaching products. In sulfuric acid leaching, the different diffraction peaks of smithsonite are off in the leaching products when sulfuric acid concentration is less than 60 g/L. After 60 g/L, the different diffraction peaks of smithsonite and siderite are off in the leaching products.

Study on Leaching Zinc Calcine with High Iron

2013 ◽  
Vol 826 ◽  
pp. 118-121
Author(s):  
Jin Lin Yang ◽  
Hong Mei Zhang ◽  
Xiu Juan Su ◽  
Shao Jian Ma
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Great Influence ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Leaching Rate ◽  
Iron Extraction ◽  
High Iron ◽  
Solid Ratio ◽  
Leaching Efficiency

In recent years, recovering zinc from zinc calcine with high iron has been a matter of discussion. In this paper, sulfuric acid leaching was carried out to assess the effect of several parameters on zinc and iron extraction in zinc calcine with high iron in which the grade of zinc and iron is 53.90% and 19.38%, respectively. Parameters, such as stirring speed, sulfuric acid concentration, liquid to solid ratio and leaching time, were investigated. The results show that leaching time has done nothing to the leaching rate, but has great influence on leaching efficiency. Liquid to solid ratio and sulfuric acid concentration have significant influence on leaching results, and stirring rate has not obvious influence on leaching results. Under the condition of 120g/L sulfuric acid, 6:1 liquid to solid ratio, 55°C leaching temperature and 120min leaching time, the recovery of zinc and iron is 82.24% and 9.64%, respectively. It is obvious that ZnO in zinc calcine is easy to dissolve in acidity solution, which shown in two aspects: high leaching rate and high leaching speed. ZnO can be dissolved entirely in sufficient sulfuric acid in 10min.

scholarly journals Intensification of Sulfuric Acid Leaching of Altered Ilmenite via Adding Fluoride Activator

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1922
Author(s):  
Anastasiia V. Dubenko ◽  
Mykola V. Nikolenko ◽  
Oleksandr O. Pasenko ◽  
Andrii Kostyniuk ◽  
Blaž Likozar
Keyword(s):  
Sulfuric Acid ◽  
Sulfuric Acid Concentration ◽  
Reaction Medium ◽  
Acid Leaching ◽  
Raw Material ◽  
Molar Ratio ◽  
Main Stage ◽  
Sulfuric Acid Leaching ◽  
Fluoride Ions ◽  
Leaching Process

A new method of altered ilmenite processing has been studied. In this method, sulfuric acid is used as the reaction medium of the process, and fluoride ions are activators of the dissolving process of the rutile part of the ore raw material. The regression model of the sulfate–fluoride leaching process was developed and analyzed by using the response surface method of 23 matrix. The obtained model is adequate and well describes the studied process. The influence of Ti:F molar ratio, temperature, and sulfuric acid concentration on the leaching process are investigated in this work in order to optimize the studied process. It is experimentally proved that leaching at temperatures above 100 °C, at a molar ratio of Ti:F of more than 1:2, and the use of solutions of sulfuric acid with concentrations of more than 85 wt.% is not optimal because the extraction degree of titanium is reduced. The intensification of the process of sulfuric acid leaching by dividing the main stage of chemical dissolution of ilmenite into two stages was proposed. This method allows to leach up to 95.9% of titanium, which is 1.6–1.9 times higher in comparison with the classical technology of leaching altered ilmenite.

Selective Acid Leaching of Copper and Zinc from Old Flotation Tailings

2020 ◽  
Vol 989 ◽  
pp. 554-558
Author(s):  
Aleksandr Bulaev ◽  
Vitaliy Melamud
Keyword(s):  
Sulfuric Acid ◽  
Acid Leaching ◽  
Distilled Water ◽  
Acid Solutions ◽  
Iron Ions ◽  
Flotation Tailings ◽  
Ferrous Metals ◽  
Non Ferrous Metals ◽  
Sulfuric Acid Solutions ◽  
Cu And Zn

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.

Trapping nitrous gases during nitric acid leaching of sulfide concentrates

2021 ◽  
pp. 29-36
Author(s):  
E. Yu. Meshkov ◽  
N. A. Bobyrenko ◽  
I. A. Parygin ◽  
A. A. Soloviev
Keyword(s):  
Sulfuric Acid ◽  
Nitric Acid ◽  
Nitrogen Oxides ◽  
Nitrogen Oxide ◽  
Acid Leaching ◽  
Process Water ◽  
Nitric Acid Leaching ◽  
Concentrated Sulfuric Acid ◽  
Sulfide Concentrates ◽  
Nitrous Gases

Gas-air mixtures that form in nitric acid leaching of sulfide raw materials possess the following peculiarities making a negative impact on trapping of nitrogen oxides: elevated temperature, different oxidation level of nitrogen oxides, slow oxidation of NO in region of low concentrations, and instability of the resulting gas-air mixture flow. Therefore, well-known methods of trapping nitrous gases shall be adapted to specific sulfide raw material. We propose a process flow diagram for trapping nitrous gases formed during nitric acid leaching of sulfide concentrates at atmospheric pressure on the example of Zhezkazgan concentrate. The paper addresses theoretical aspects of the use of water-ore pulp, concentrated sulfuric acid, process water and alkaline agents for trapping nitrous gases, and typical reactions of interaction of the proposed absorbents with nitrogen oxides. The choice of water-ore pulp as an absorber was made because of similarity between the mechanism of absorption of nitrogen oxides for neutral and alkali ore suspensions and the one for alkali solutions: nitrogen dioxide and nitrous anhydride are absorbed with formation of a solution of nitrates and nitrites. Due to availability in a liquid phase of ferrous iron along with NO2 and N2O3, acidic suspensions are also capable to absorb nitric oxide, to some extent, with formation of Fe(NO)SО4 complex. Process water absorbs only nitrogen dioxide, with formation of nitric and nitrous acids. Nitrous acid is an unstable compound in acidic environments and decomposes with formation of water and nitrogen oxide. At the stages of trapping nitrogen oxides with water-ore pulp and process water (circulating solution), it is recommended conditioning of gas-air mixtures by choosing the volume of additionally introduced air, in an amount to provide the highest rate of nitrogen oxide oxidation. At the stages of sulfuric acid and alkaline trapping of nitrogen oxides, it is recommended conditioning of gas-air mixtures by selecting the volume of additionally introduced air and the oxidation time of nitrogen oxide that provide an equimolecular mixture of NO and NO2. A distinctive feature of the use of water-ore pulp, concentrated sulfuric acid, process water and alkaline agents for trapping nitrous gases is possibility to use the products of absorption at the stage of sulfide concentrate leaching. The extended tests of trapping nitrous gases have been conducted. The plant capacity by the gas-air mixture ranged 17–21 m3/h, and by leached concentrate — 12–15 kg/h. In this case, the degree of capturing nitrous gases reached 96.8%. Return of the products of absorption of nitrous gases in the form of condensate, water-ore pulp, nitrosyl sulfuric acid, nitric acid solution, nitritenitrate lye allows to reduce the nitric acid consumption by 7–10 times relative the values obtained without using the trapping system. In this case, the degree of copper extraction into the leaching solution was 97.7%. The extraction degree of silver, rhenium, zinc was respectively 98.0%, 99.0%; 98.5%.

Atmospheric Acid Leaching of a Ferruginous Nickel Laterite

2013 ◽  
Vol 634-638 ◽  
pp. 3196-3200
Author(s):  
Kui Liu ◽  
Xue Mei Su
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Atmospheric Pressure ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Nickel Laterite ◽  
Nickel Extraction ◽  
Solid Ratio ◽  
Acid Consumption ◽  
Two Factors

A ferruginous nickel laterite was leached by sulfuric acid at atmospheric pressure. Nickel extraction was largely dependent on sulfuric acid concentration and leaching temperature. Besides these two factors, leaching time and liquid/solid ratio also influenced cobalt extraction significantly. Nickel was easier to be extracted than cobalt. About 95% nickel and cobalt could be extracted when leaching with 5mol/L sulfuric acid for 2h at 100°C, and the acid consumption was 1.417kg H2SO4/kg dry ore.

scholarly journals Cleaner Production of Chromium Oxide from Low Fe(II)-Chromite

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 460 ◽  
Author(s):  
Qing Zhao ◽  
Chengjun Liu ◽  
Peiyang Shi ◽  
Lifeng Sun ◽  
Maofa Jiang ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Processing Parameters ◽  
Dissolution Behavior ◽  
Optimum Process ◽  
Process Conditions ◽  
Box Behnken Design ◽  
Functional Relationships ◽  
Leaching Process

Sulfuric acid-based leaching is a promising cleaner method to produce chromium salts, but its feasibility for treating low Fe(II)-chromite still remains to be proven. A Box–Behnken design (BBD)-based set of experiments for sulfuric acid leaching of low Fe(II)-chromite was utilized in this work for generating an experimental dataset for revealing the functional relationships between the processing parameters and the extraction yields of Cr and Fe. The dependent variables were found to exhibit strong intercorrelations and the models developed on the basis of statistical criteria showed excellent prediction accuracy. The optimum process conditions of leaching treatment were found to be a temperature of 176 °C, a dichromic acid/chromite mass ratio of 0.12, and a sulfuric acid concentration of 81%. Furthermore, the dissolution behavior of chromite in the leaching process and the effect of dichromic acid were experimentally investigated. It was found that the decomposition efficiency was highly dependent on the Fe(II) content of chromite, and that the dichromic acid acted both as an oxidant and a catalyst in the leaching process. On the basis of the results of this study, a novel process for treating low-Fe(II) chromite was proposed.

Investigation and optimization of influencing parameters on the copper extraction from a low-grade oxide deposit by acid leaching

2019 ◽  
Vol 116 (3) ◽  
pp. 305
Author(s):  
Mostafa Hosseinzadeh ◽  
Mohammad Raouf Hosseini
Keyword(s):  
Sulfuric Acid ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Solid Content ◽  
Copper Extraction ◽  
Low Grade ◽  
Operational Parameters ◽  
Operational Variables ◽  
Contour Plots ◽  
Residuals Analysis

Recovery of copper (II) from a low-grade deposit obtained from the rejects of a crushing circuit was investigated by means of leaching using H2SO4solution. Sulfuric acid concentration was between 30–180 g/L, solid content was set at 10–60%, particles were in the size range of −1 + 2 mm, and the leaching time was 5–60 min. Initially, a screening step was utilized involving a full factorial design (FFD) with four factors at two levels and two replications. Normal probability plot of residuals, analysis of variance (ANOVA), surface plots, and contour plots were used to study the effects of the main operational parameters and their interactions. The results of ANOVA,F-test andt-student test showed that at 95% confidence level, the sulfuric acid, solid content, leaching time, and the 2-way interaction of them considerably affected Cu(II) extraction, and increasing their value positively influenced the Cu(II) extraction. A factorial regression model was developed to relate Cu(II) extraction and the operational variables. The fitted model presented a good agreement between the experimental data and the predicted values with a correlation coefficient (R2) of 0.9989. Optimization of Cu(II) extraction suggested that the optimum conditions for Cu(II) extraction (Re = 72%) were sulfuric acid: 90 g/L, solid content: 50%, particle size: under 2 mm, and leaching time: 30 min.

Kinetics of Pressure Acid Leaching of Zinc from Zinc Silicate Ore

2011 ◽  
Vol 402 ◽  
pp. 266-271
Author(s):  
Hong Sheng Xu ◽  
Chang Wei ◽  
Cun Xiong Li ◽  
Yan Song ◽  
Zhi Gan Deng ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Acid Concentration ◽  
Sulfuric Acid Concentration ◽  
Acid Leaching ◽  
Zinc Silicate ◽  
Diffusion Control ◽  
Pressure Leaching ◽  
Zinc Extraction ◽  
Shrinking Core ◽  
Sulfuric Acid Solutions

The present work is concerned with the kinetic study of pressure leaching of zinc silicate ore in sulfuric acid solutions. The effects of leaching temperature, particle size, sulfuric acid concentration and agitation speed on the zinc extraction were evaluated. The results obtained show that the zinc extraction increases with increasing sulfuric acid concentration and leaching temperature. The leaching kinetics was analyzed by using a shrinking core model with diffusion control given by: 1-2/3x-(1-x)2/3=Kt, which represented well the experimental data. The apparent activation energy was determined to be 44.56kJ/mol at temperatures ranging between 80 and 140°C.

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