Sulfuric Acid Leaching Research Articles

Поисковые исследования по гидрометаллургической переработке медьсодержащей руды месторождения Кеншокы-1

The main purpose of these studies was to study the chemical and mineralogical composition of the ore of the Kenshoky-1 deposit with subsequent search experiments on the extraction of copper from ore material by sulfuric acid leaching. During the research it was established that the ore belongs to the type of oxidized cuprous sandstone and along with copper it contains a significant amount of lead and a small amount of zinc. The main minerals of copper and lead in this ore are carbonate – malachite and cerussite. A fairly significant amount of the lead phosphate mineral pyromorphite is present. The main minerals in the waste rock are quartz, orthoclase, and clinochlorine. Iron, according to diffractometric analysis, is bound in clinochlore. The search experiments on copper leaching from the mentioned ore by sulfuric acid solutions showed that even at room temperature and sulfuric acid concentration in the solution of 11.3 g/dm3 extraction of copper in aqueous solution of more than 60% is achieved, and the main technological factors influencing the process of copper leaching are duration, concentration of sulfuric acid in the initial solution, intensity of agitation and the ratio of solid and liquid phases. The concentration of copper in the resulting pregnant solution was, depending on the concentration of sulfuric acid from 6.32 to 10.15 g/dm3 , which is insufficient for further processing of solution by electrolysis, therefore, productive solutions must be additionally saturated with copper by returning pregnant solution to the head of the process. Lead behavior during prospecting studies was not studied, but due to low solubility of lead sulfate in aqueous solutions, the main part of lead should remain in the cake

Recovery of Valuable Metals from Polymetallic Refractory Concentrate by a Sulfuric Acid Curing and Leaching Method

Sulfuric acid curing and leaching is a promising technology for treating refractory ores. In this work, a refractory concentrate containing 3191 ppm uranium (U), 2135 ppm niobium (Nb), and 0.7% rare earth minerals (REMs) went through two stages: curing by high-concentration H2SO4 and leaching by low-concentration H2SO4. We investigated the behavior of those valuable metals during the two stages. For both curing and leaching, the operating parameters include the acid-to-solid ratio, time, temperature, and H2SO4 concentration. The recovery for U, Nb, and REMs was as high as 95%, 86%, and 73.5% using a curing acid-to-solid ratio of 1:1, curing temperature of 200 °C, curing time of 1 h, H2SO4 concentration of 98%, leaching liquid-to-solid ratio of 4:1, leaching time of 2 h, leaching temperature of 60 °C, and leaching H2SO4 concentration of 5 g/L. A “sulfuric acid curing–leaching-U extraction by N235–Nb recovery by resin adsorption–REMs’ recovery by resin adsorption” method was implemented, where the overall U, Nb, and REMs’ recovery reached 93.1%, 84.5%, and 69.6%, respectively.

Possibility of Improving Parameters of the Sulfuric Acid Leaching of Reduced Ferriferrous Laterite Ores with Selective Nickel and Cobalt Recovery

Possibility of Improving Parameters of the Sulfuric Acid Leaching of Reduced Ferriferrous Laterite Ores with Selective Nickel and Cobalt Recovery

Kinetics of aluminum extraction from roasting activated fly ash by sulfuric acid leaching

Kinetics of aluminum extraction from roasting activated fly ash by sulfuric acid leaching

Energy effective utilization of circulating fluidized bed fly ash to prepare silicon-aluminum composite aerogel and gypsum

To reduce the cost of Si-Al aerogels preparation, circulating fluidized bed fly ash (CFA) was developed to be as the alternative to synthetic precursors. High energy consumption of alkali-melting and secondary wastes production were the major challenges. Here, a technique characterized by effective energy consumption and non-secondary waste was developed to convert CFA into Si-Al aerogel. The process consists two stages, preparation of Si-Al sol by sintering of CFA and Na2CO3 followed by sulfuric acid leaching, and synthesis of Si-Al aerogel by so-gel with trimethyl chlorosilane modification and ambient pressure drying. The optimization results of proportion and sintering temperature showed that the optimal temperature of sintering of Na2CO3 and CFA with the mass ratio of 0.7 was 750 °C, 100 °C lower than that of most other waste aluminosilicate materials. CaSO4·0.5H2O which meet building gypsum requirement was obtained by specifying the drying temperature of acid-leached residue at 126 °C for 2 h. The modification procedure was explored to obtain Si-Al aerogel with a large specific surface area of 857 m2/g and hydrophobic angle of 139.3°. Thermal and mechanical properties tests indicated that the Si-Al aerogels and gypsum produced from CFA exhibited promising thermal insulation and the potential application in construction.

Surfactants and their mixtures under conditions of autoclave sulfuric acid leaching of zinc concentrate: Surfactant selection and laboratory tests

The influence of surfactants and their mixtures on the efficiency of the pressure leaching of zinc concentrates was studied by leaching tests and subsequent analysis, including granulometric and phase composition studies of the leaching products. Lignosulfonate (LS) and sodium dodecyl sulfate (SDS) were used as surfactants. Additional experiments were performed on artificial solutions to study the effect of surfactants on the solution surface activity by surface tension measurements. The obtained results indicated a synergistic effect of the combined LS and SDS addition, resulting in surface tension reduction. In a series of pressure leaching tests, the effects of the concentration of surfactants and their mixtures (CLS/SDS=0.2−0.8 g/L), temperature (T=120−140 °C), oxygen partial pressure (pO2=0.5−0.7 MPa), and time (t=20−120 min) on the extraction of zinc, iron, copper and indium into solution were investigated. Based on the results, optimal parameters were determined to carry out the leaching of zinc concentrates: surfactant mixtures of the composition CLS=0.6−0.8 g/L, CSDS=0.2−0.6 g/L, pO2=0.5 MPa, T=140 °C, and t=100−120 min. These optimal conditions result in extraction of 93%−94% zinc, 65%−66% indium, 64%−68% copper, and 48%−49% iron into solution.

Efficient Copper Recovery from Chalcopyrite Using an «Isopropanol–Sulfuric Acid–Sodium Dodecyl Sulfate» System

In this study, SDS is used to enhance the sulfuric acid leaching of chalcopyrite in aqueous and isopropanol media. The presence of SDS increased copper extraction into the solution in both solvents. However, it was the “isopropanol–sulfuric acid–SDS” system that proved to be particularly effective for copper recovery from chalcopyrite. The positive effect of SDS can be attributed to the reduction in the solution’s surface tension and the enhancement of mineral wetting. Additionally, the presence of SDS as a surfactant induces changes in the adsorption patterns of formed sulfur species on the mineral surface. SDS competes with sulfur for occupancy on the surface binding sites. This competitive interaction has the potential to diminish the formation of a substantial sulfur layer on the mineral surface. Under optimal conditions (isopropanol media, 2 M H2SO4, 65 °C, 120 min, 0.6 g/L SDS), copper recovery into the solution was 83%, and this is a considerable achievement for chalcopyrite leaching at ambient pressure in the absence of strong oxidizers.

Exploratory Data Analysis of the Groundwater Contaminants at the Former Panna Maria Uranium Recovery Facility.

The former Panna Maria mill was a uranium recovery facility that operated from 1979 to December 1992. Sulfuric acid leach was used to process several tons of ore daily. Therefore, the groundwater was sampled at the site to monitor the concentration of background chemical pollutants. The purpose of this study was to perform exploratory data analysis to evaluate whether the arsenic, nickel, selenium, sulfate, and uranium concentrations were in accord with state-regulated groundwater drinking standards at the site. To accomplish this, a substitution method was used to replace concentration values that were below measurable ranges of well monitoring units. Additionally, random forest regression was employed to account for missing not-at-random values in the dataset. Groundwater samples collected in wells before the facility began operations were used to determine an upper bound on background pollutants consistent with US Environmental Protection Agency Standards. The upper tolerance limit comprising 90% of the groundwater sample at a confidence coefficient of 95% was used to establish alternate concentration limits for each chemical based on well data from the National Uranium Resource Hydrogeochemical and Stream Sediment Reconnaissance program. Results obtained in this analysis establish a baseline on the chemical concentrations in the background groundwater at the former Panna Maria mill.

Organic phase modification of YW100 extraction system: Extraction of germanium using YW100 + D2EHPA + N235

In this study, germanium was selectively extracted using an organic phase containing 3% C7-9 hydroxamic acid (YW100), 15% Di(2-ethylhexyl)phosphoric acid (D2EHPA), 35% Tri(octyl-decyl) amine (N235), and 47% kerosene from the Ge-slag sulfuric acid leaching solution. Then, the solution was stripped by the 1 mol/L NH4F solution to obtain a germanium extraction ratio of 99.4% and a stripping ratio of 96.2% after three extraction and stripping stages. The total organic carbon (TOC) was used to characterize the total organic matter amount in the raffinate. Compared to the “YW100 + D2EHPA” extraction system, the “YW100 + D2EHPA + N235” extraction system reduced 80% of the water solubility loss of YW100 and improved the phase separation performance. In addition, the mechanisms of germanium extraction and phase separation improvement were studied. The coordination number of YW100 and germanium is 3, while the coordination number of D2EHPA is 1.

Facile and complete sulfuric acid leaching of zinc ferrite assisted by copper powder: Leaching mechanism and kinetics investigation

Zinc ferrite is a dominant phase in mass solid wastes generated from zinc or iron production, which causes the obstacle of metal recovery and recycling. A facile and efficient sulfuric acid leaching process of zinc ferrite assisted by copper powder was proposed in this study. The effects of factors on the leaching of zinc ferrite and copper were investigated. The results showed that zinc ferrite and copper were coupled and leached. The complete dissolution of zinc ferrite was obtained with wide ranges of leaching conditions. The shortest time for the complete dissolution of zinc ferrite was 10 min at 80 ℃ under the conditions: copper to zinc ferrite molar ratio of 1.5, sulfuric acid concentration of 100 g/L, liquid to solid ratio of 30 mL/g, and copper powder of + 38.5–20 μm. The least consumption of copper to realize the complete dissolution of zinc ferrite was 27.15%. The leaching kinetics was studied by the shrinking core model. It was found that zinc ferrite leaching assisted by copper was controlled by surface chemical reaction. The apparent activation energies for zinc, iron, and copper are 56 kJ/mol, 56 kJ/mol, and 50 kJ/mol, respectively. Characterization of the leaching residues and determination of iron and copper species in the leaching solution showed galvanic corrosion took place between zinc ferrite and copper, enhancing their acid dissolution.

Selective extraction of Ni and Co from a pyrrhotite-rich flotation slime using an alkaline glycine-based leach system

Ni and Co, mostly produced from sulfide resources, are critical energy metals required for the green energy transition. A significant portion of the Ni and Co in the processed ore, particularly for disseminated mafic/ultramafic ores, is not recovered due to the deportment to fine slimes which has been dumped as tailings during the flotation process. This study applied an alkaline glycine-based leaching method to selectively recover Ni and Co from a pyrrhotite-rich flotation slime and investigated the deportment of impurities. Leaching variables, including dissolved oxygen (DO) level (5–25 ppm), pH modifier (NaOH, KOH and ammonia), particle size and pre-oxidation, were investigated. The highest extractions of 86.2 % for Ni and 79.7 % for Co were achieved by leaching at glycine/(Ni + Cu) molar ratio of 4, DO of 15 ppm, pH of 10.2 (adjusted with ammonia), 10 % solids and 30 °C using a sample size at a grind size P80 of 17 µm within 72 h. Ni that is mineralised in pentlandite can be easily leached by glycine, and oxygen addition is essential for the extraction of Ni and Co when mineralised as sulfides. The study has shown a higher overall metals extraction and faster leaching kinetics, shortening the leaching from 72 to 24–48 h, when ammonia was used as a pH modifier. The alkaline glycine-based leaching achieved both higher Ni and Co extractions and higher rejections of impurities compared with conventional sulfuric acid leaching, with the concentrations of Fe being <250 ppm and Ca and Mg <15 ppm in the leachate. Residue analysis revealed a mechanism of preferable dissolution of pentlandite over pyrrhotite. The Fe and Mg deportment before and after leaching remained similar, which confirmed the high selectivity of the alkaline glycine-based leaching.

High recovery of lithium from coal residue by roasting and sulfuric acid leaching

As the price and demand for lithium metal continue to rise, super-enriched lithium coal is expected to become a new resource to obtain lithium, but there are little research studies on methods for extraction process and mechanism. In this study, a lithium-rich coal residue was leached with H2SO4 after roasting activation without any additive. The properties and morphology of raw ore, calcined samples and leaching residue were characterized by proximate analyses, XRF, ICP-OES, XRD and SEM-ESD. The major chemical compositions were Al2O3 (26.46 %), SiO2 (41.35 %), C (9.43 %) and the valuable lithium content was 550 mg/kg. The main phase compositions of the raw coal residue are kaolinite, quartz, anatase, gypsum and muscovite. The highest leaching efficiency of lithium was achieved under conditions of calcination at 500 °C, leaching reaction time of 40 min, in 15 % wt/v sulfuric acid concentration at a leaching temperature at 90 °C. The occurrence at lithium was closely associated with the kaolinite. The mechanism of roasting activation is that kaolinite loses its structural hydroxyl group and transforms into metakaolinite, and the exposed lithium can undergo ion exchange and minerals dissolution reaction with sulfuric acid.

Study on Sulfuric Acid Leaching and Purification of Zinc Ferrite by Roasting Zinc-Containing Gossan Ore

Study on Sulfuric Acid Leaching and Purification of Zinc Ferrite by Roasting Zinc-Containing Gossan Ore

Deep Processing of Dump Slag from the Copper-Nickel Industry

This work proposes an environmentally safe and economically feasible method of waste copper-nickel production slag utilization (Kola Mining-Metallurgical Company, Nornickel, Kola Peninsula, Russia). This process involves the decomposition of slag by diluted solutions of sulfuric acid (7–10 wt.% H2SO4) with a transfer in a solution of more than 70% silicon, 77% iron and 78% magnesium, and a concentration of non-ferrous metals in the residue (~70%). Copper ions were used in the leaching stage to prevent the release of hydrogen sulfide into the working atmosphere. Dehydration of the solution, followed by washing of water-soluble sulphates from silica, was carried out to separate silica from the leaching solution. The dehydration temperature effect on the silica structural characteristics was determined. The possibility of recovering non-ferrous metals from solutions after silica extraction by precipitation, in the form of copper cementite, and the sum of nickel and cobalt sulfides, was evaluated. Pigment-grade iron dioxide, magnesium sulphate and aluminium hydroxide were obtained by dehydration of the solution after extraction of base metals, calcination and other operations. Sulfuric acid leaching resulted in the disclosure of sulfide grains encapsulated in ferrosilicate, which is a favorable factor for flotation. The depleted residue can be successfully used in the construction industry.

Bioleaching and Chemical Leaching of Lateritic Ore in Percolators

This work presents results of an initial exploration of nickel and cobalt bioleaching from lateritic ores in small percolators, which serve as simulations of the heap leaching process. Heap leaching offers an attractive alternative to high-pressure acid leaching of laterites, owing to its relatively simple technology, reduced capital and operational expenses, and lower carbon dioxide emissions. Conventional heap leaching of laterites relies on sulfuric acid leaching. Typically, this process consumes 400-500 kg/t of ore, necessitating the construction of a costly on-site sulfuric acid plant. However, the metabolic activity of sulfur-oxidizing bacteria can generate sulfuric acid while reducing ferric to ferrous iron, facilitating mineral dissolution through a combined protonation and reduction effect. Implementing this process eliminates the need for a sulfuric acid production plant, as the bacteria oxidize sulfur within the leaching heap. The results presented in this paper demonstrate comparable efficiencies between bioleaching and chemical leaching with sulfuric acid for nickel extraction, underscoring the importance of ferrous iron in enhancing leaching efficiency.

Thermodynamics Study for Selective Leaching of Copper and Zinc from Complex Secondary Raw Materials Using Oxidative Sulfuric Acid Leaching

This study focuses on evaluating the optimal process conditions for selectively leaching copper and zinc from complex secondary raw materials using the oxidative sulfuric acid leaching process. The research includes both physical and chemical characterization of the materials and a comprehensive thermodynamic analysis to assess the thermodynamic properties and behaviors of the system under investigation. The physical characterization involves determining parameters such as bulk density, moisture content, and granulometric composition of the samples. Elemental composition analysis is performed using X-ray fluorescence spectrometry (XRF) and energy dispersion spectroscopy (EDX), while the phase composition is determined through X-ray diffraction (XRD) analysis. Additionally, the materials' morphology is examined using scanning electron microscopy (SEM). Fraction diagrams are created using Hydra/Medusa software to assess the phase distributions of zinc and copper during the leaching process. The stability of the metals and potential chemical reactions within a defined temperature range is analyzed using Eh-pH diagrams with the HSC 9 Chemistry Software. Based on the thermodynamic analysis conducted, it is determined that effective leaching of copper and zinc from the complex secondary raw materials is achievable. Furthermore, the results indicate that the leaching process is relatively insensitive to temperature variations. The optimization of the leaching process should primarily focus on achieving optimized consumption of the oxidizing agent.

The Effect of Process Conditions on Sulfuric Acid Leaching of Manganese Sludge.

Manganese sludge, an industrial waste product in the ferroalloy industry, contains various components and holds significant importance for sustainable development through its valorization. This study focuses on characterizing a manganese sludge and investigating its behavior during sulfuric acid leaching. The influence of process conditions, including temperature, acid concentration, liquid to solid ratio, and leaching duration, was examined. The results revealed that Mn, Zn, and K are the main leachable components, and their overall leaching rates increase with increasing temperature, liquid to solid ratio, and time. However, the acid concentration requires optimization. High leaching rates of 90% for Mn, 90% for Zn, and 100% for K were achieved. Moreover, it was found that Pb in the sludge is converted to sulfate during the leaching, which yields a sulfate concentrate rich in PbSO4. The leaching process for Mn and Zn species appears to follow a second or third order reaction, and the calculation of rate constants indicated that Mn leaching kinetics are two to five times higher than those for Zn. Thermodynamic calculations were employed to evaluate the main chemical reactions occurring during leaching.

Vanadium–Titanium Magnetite Concentrate, Calcium–Magnesium Composite Roasting and Sulfuric Acid Leaching for Vanadium Extraction from Pellets

This paper investigated a pellet ore production process in which vanadium was extracted from vanadium and titanium magnetite concentrates using sulfuric acid leaching. Calcium and magnesium were added to the iron ore concentrate during pellet production to produce calcium vanadate and magnesium vanadate after roasting. The pellets were leached with sulfuric acid solution to extract V5+. The resulting pellets had a compressive strength of 3375 N after primary roasting, a good pellet morphology after acid leaching, and simple liquid–solid separation. Under the optimal experimental conditions, the vanadium leaching rate in the pellets reached 77.86%, while the iron leaching rate was only 1.17%. The pellets did not fragment, which was an improvement upon existing vanadium extraction methods. The strength of the pellets after vanadium extraction decreased to 563 N, but after secondary roasting, the compressive strength of the pellets reached 2578 N, which was suitable for blast furnace ironmaking. The roasting and acid leaching experiments showed that the vanadium extraction process resulted in suitable pellet properties. The use of low compound additives can effectively improve the leaching effect, while avoiding the previous problems of too many additives, pellet iron grade reduction, or the pursuit of high vanadium extraction rate pellet breakage and serious high secondary use process costs.

Sulfuric Acid Leaching of Zn and Mn from Waste Zn–C Batteries Using Fe2+ as Reductant

Sulfuric Acid Leaching of Zn and Mn from Waste Zn–C Batteries Using Fe2+ as Reductant

Study of Factors Affecting the Copper Ore Leaching Process

This paper provides an overview of hydrometallurgical copper extraction studies in which liquid extraction technology has been used with four copper deposits of different compositions. The sulfuric acid consumption rate and copper extraction efficiency, which are dependent on the initial content and forms of calcium compounds and other impurities in ore samples, were calculated, and the results are presented herein. It was established that during the leaching process, silicate compounds of alkaline earth metals, in addition to calcium and magnesium carbonate compounds, would affect the levels of sulfuric acid consumption, thereby actively lowering the acidity of the environment. Moreover, these compounds could partially sorb copper ions from sulfuric acid leaching solutions. Thus, the analysis of waste ore samples showed that residual copper is mainly contained in the form of complex silicate complexes. The presence of divalent iron compounds in the composition from one of the deposits also allowed us to perform a biochemical leaching experiment with preliminary oxidation using an Acidithiobacillus ferrooxidans bacterial culture adapted to the ore composition. The use of this biochemical method in the copper leaching process resulted in a significant reduction in sulfuric acid consumption, by 40%, and a copper recovery rate of 87.2%.