We investigated the leaching of copper with Phanerochaete chrysosporium (P. chrysosporium) from waste printed circuit boards (WPCBs). Leaching of copper after treatment with P. chrysosporium for 14 days was 60.96%, which was 9 times higher than that in absence of the fungi. After 14 days of treatment with fungi, the copper clad laminates of printed circuit boards were seriously corroded without any

Supply of rare earth elements (REEs) critical to the development and maintenance of industrialized economies has become uncertain in recent years owing to the limited number of REE producers. In order to develop alternative REE sources, new mines are being explored and end-of-life secondary sources have been targeted for REE recovery. However, the composition of ores and secondary sources often differ

There is a growing interest in exploring the application of bioleaching for treating copper sulfide ores of decreasing grade and located at larger depth by in situ recovery (ISR) for its potential savings in ore extraction, crushing, grinding and the avoidance of tailings. As copper sulfide ores are usually present in well consolidated rocks a crucial aspect for ISR to be successful is to increase

The pretreatment of carbonaceous material in double refractory gold ores (DRGO) is necessary to decrease preg-robbing of gold and maximize gold recovery. DRGO contains of carbonaceous matter and gold grains encapsulated in sulfide minerals, which typically results in very poor gold recovery. However, there is growing interest in DRGO because some estimates show that it makes up about a third of the

Efficient electrowinning is critical for industrial tellurium (Te) production. To overcome the bottlenecks of a low production rate and low recovery in conventional processes, Te electrowinning tests with three different current densities were conducted in an industrial pilot-scale cyclone electrowinning cell. A numerical simulation of the flow field and electric field in the electrowinning cell was

A patented hydrometallurgical approach (KellGold) for high-yield, cyanide-free recovery of metals from refractory gold and polymetallic concentrates is summarized. Drivers include elimination of atmospheric emissions of SO2, As2O3 and Hg produced by smelters and roasters, as well as cyanide risks arising from transportation, operations and detoxification activities. The Kell process comprises several

The chromium-containing industrial wastewater, as a type of common widespread hazardous waste, causes many environmental issues. This study aimed to develop a novel amide as extractant and evaluate its recovery of chromium(VI) in aqueous solutions. Comparing nine amides with different alkyl groups and six diluents with different polarity, 40% (v/v) C14H29NO and 60% (v/v) D80 were found to be the best

The synergistic leaching system using glycine as the main lixiviant with low levels of cyanide as a catalyst has been shown to be an effective approach to leach gold‑copper ores and concentrates, allowing the consumption of cyanide to be remarkably reduced. The recovery of gold from the synthetic cyanide-starved glycine leachate in the presence of copper has been investigated using. It was found that

This paper evaluates the recovery of gold through selective acid leaching of connector pins removed from waste central processing units (WCPU) of computers. The exclusive treatment of this electronic component appears as a promising alternative since it minimizes gold losses. The experimental approach consisted by leaching steps of different types of pins aiming at dissolving all the metals that make

A generalized non-porous shrinking particle model (G NSPM) of leaching has been verified and used for numerical simulations. Unlike the commonly used “simple” non-porous shrinking particle model (S NSPM), the G NSPM assumes n− th order chemical reaction, the influence of the L/S ratio and non-ideal behaviour of the leach solution. The leaching of dead-burned magnesite with hydrochloric acid has been

The effect of ultrasound on gold leaching rate and kinetics was investigated in the Co-NH3-S2O32− system. First, the effects of ultrasound power, temperature, the concentration of thiosulfate, cobalt and ammonia on gold leaching rate were studied under ultrasound. The optimized leaching parameters are 0.03 M Co2+, 0.2 M S2O32−, 1 M NH3, 323 K, and 750 W ultrasonic power. Moreover, the leaching rate

Scheelite is a calcium tungstate mineral that is an important ore of tungsten. It also contains small amounts of rare-earth metals, that enter the leaching liquor along with tungsten (W) after decomposition of the ore with H2SO4–H3PO4 mixed acid. In this study, a novel process was developed to effectively extract and separate tungsten and light rare earth (LRE) from this leaching liquor. La will represent

Dealkalization is a major limiting factor for the comprehensive utilization of red mud, and acid leaching is considered an effective and promising way to achieve it. Most studies have focused on the recovery of metals in this extreme alkaline waste by strong acid leaching, ignoring the dealkalization and stabilization of red mud with low concentrations of acid. In this study, the leaching behavior

The effect of a thermal pretreatment on the kinetic parameters and rate-controlling step for nickel leaching dissolution in hydrochloric acid‑sodium chloride solutions from a low – grade Colombian nickel laterite (1.15% Ni, 0.12% Co and 41.1% Fe), was evaluated. The mineralogical analysis showed that nickel is associated with iron in the form of hematite (Fe2O3) and goethite (FeOOH) within the calcined

Tailings are remaining processing waste streams from mines, disposed after valuable minerals extraction from the mined ore. Tailings contain varying concentrations of residual valuable metals that are currently lost due to lack of economical treatment possibilities. With sulfide containing tailings there is also a risk of acid rock drainage. In this study, iron- and sulfur-oxidizing microorganisms

The reaction mechanism of the organic reagent removing VOCl3 from crude TiCl4 has been explored, which is key to optimize industrial application. In this study, a comprehensive reaction mechanism is conducted via various characterization techniques and computational studies, such as XRD, XPS, Raman, SEM, density functional theory calculations and thermodynamic calculation etc. The results show that

The catalytic mechanism of activated carbon-assisted bioleaching of enargite concentrate (enargite 37.4%; pyrite 47.3%) was investigated by employing microbiological, electrochemical and kinetic studies. By using moderately thermophilic microorganisms at 45 °C, the final Cu dissolution was improved from 36% to 53% at 0.2% (w/v) activated carbon. An excess activated carbon addition showed an adverse

In this study, a refractory Au-Ag ore from Beiya (Yunnan, China) was characterised and the occurrence states of low-grade gold and silver were clarified. The results revealed that the gold in the ore mainly occurred as visible native gold, which can be leached easily via cyanidation, whereas the visible silver minerals occurred as native silver, acanthite, chlorargyrite, acanthite, pyrargyrite, andorite

Naturally occurring manganese (Mn) oxide, biogenic birnessite ((Na, Ca, K)0.5 MnIII, IV2O4·1.5 H2O), is involved in the geochemical cycling of variety of metals including arsenic (As). This natural reaction was exploited in this study to develop a sustainable oxidation treatment process of As(III) to the less soluble (and less toxic) As(V). It is known that the birnessite surface becomes passivated

A microbial method using baker's yeast (Saccharomyces cerevisiae) was developed to collect aqueous Pd(II) ions through bioreductive deposition and biosorption at room temperature. Resting cells of S. cerevisiae reduced 1.0 mol/m3 aqueous Pd(II) ions in a Na2PdCl4 solution to metallic Pd(0) at pH 7.0 within 60 min when formate was provided as the electron donor under anaerobic conditions. Palladium

Chalcopyrite leaching in acidic ferric sulfate media was improved by addition of ethylene thiourea (ETU) in shaking flask tests with the iron-oxidizing bacterium acidithiobacillus ferrooxidans. In bioreactor experiments, ETU was able to solubilize the chalcopyrite even after the mineral was pre-leached under non-catalytic conditions. Surface analysis of leached chalcopyrite mineral specimens by scanning

Tellurium nanoparticles (TeNPs) are extensively used in biomedicine, electronics and some other industrial applications. Few microorganisms have been studied for the production of TeNPs either under aerobic or anaerobic conditions. Remarkably, this study is the first report of a bacteria able to perfectly grow anaerobically and aerobically in the presence of both tellurium oxyanions, TeO32− and TeO42−

The continuous solvent extraction operations for the removal of molybdenum from ammonium tungstate solution was conducted using a solvent extraction system consisting of 10% (v/v) N263 as extractant and 30% (v/v) isooctanol as modifier in sulfonated kerosene for 63 h under optimized conditions in mixer-settlers. The concentration of Mo in raffinate was less than 10 mg/L with mass ratio of Mo/WO3 less

Copper electrowinning reagents include levellers which are included to control deposit growth characteristics. These additives are made up of high molecular weight molecules such as the polysaccharide type (e.g. Guar gum) and less common polyacrylamide (PAM) type. Adsorption of these molecules at the surface of the deposit facilitates deposit levelling. To improve performance of these molecules it

In this study, the influence of Co2+ (2 g/L) on the electrochemical behavior of cast Pb−Ag (0.6 wt%) anode and cast Pb anode was investigated in diaphragm electrolysis by galvanostatic polarization, cyclic voltammetry, and anodic polarization and with Tafel curves. In addition, analyses of the anodic weight loss, metal ion concentration, phase analysis, and scanning electron microscopy images of the

In order to tackle the dual challenge of utilizing highly refractory chalcopyrite (CuFeS2) while saving scarce freshwater resources, this study aimed to systematically understand the individual role of chemical lixiviant and bioleaching microorganisms in the complex Fe3+-Cu2+-SO42−-Cl− chalcopyrite leaching system. In general freshwater bioleaching conditions, the Eh level sharply increased, and the

The abundance of limonitic laterite ores in tropical and sub-tropical areas represents a large, and mostly unexploited, cobalt resource. Bioprocessing oxidised ores, and also waste materials such as tailings and processing residues, using acidophilic microorganisms to catalyse the reductive dissolution of iron and manganese minerals, is an environmentally benign alternative approach of extracting valuable

The first two-stage zinc pressure leaching plant with 100 kt-Zn/a capacity in China was put into production in 2009, to recover zinc, rare metals, germanium and gallium. However, the total extraction of zinc is limited to just 93% in initial production. To improve the co-recovery of metals, pressure leaching tests were carried out on the first-stage leach residue from the initial flowsheet. The effects

Leaching of active cathode materials of Li-ion batteries (LIB) is a hotly contested topic. In the published literature, the best processes utilize concentrated acid (e.g. 2–3 M H2SO4) and elevated temperatures for waste LIB leaching, along with unstable reduction reagents such as H2O2. In this study, we demonstrate the dissolution of LiCoO2 (LCO) in a low-acid leaching system that utilizes typical

It is a challenge to recover copper from low grade ore in an environmentally sustainable way, especially from low-grade copper sulfide resources. This paper introduces Zijinshan Mine where an integrated process was developed and applied to recover copper from low-grade copper sulfide ore and acid mine drainage (AMD). The process includes the main operations of milling-flotation, heap bioleaching, solvent

In this paper, a process of selective extraction and separation of vanadium (IV) from acid leaching solution of spent oil hydrotreating catalyst by a solvent extraction method with P204 as an extractant was proposed. Because the leaching solution contained a large amount of elements such as nickel, aluminium and iron, the effects of various conditions on the separation of vanadium from nickel, aluminium

Experiments were carried out to test the amenabilities of mineral deposits that contained cobalt deported in arseno-sulfide (cobaltite) and arsenide (skutterudite) minerals, to oxidative bioleaching at mesophilic temperatures and low pH. An ore sample from the Iron Mask deposit (Canada) and a mineral concentrate from a working mine (Bou Azzer, Morocco) were thoroughly characterised, both prior to and

Solid waste tailings from acid leaching of Gattar mineralized ore material contain economic and valuable minerals were processed to obtain some economic products. Firstly, these tailings were upgraded to a high‐‑titanium concentrate, which was then roasted with newly used (NaOH/Na2CO3) flux, for which the most suitable conditions for roasting were established. Then, the roasted masses were leached

In the present study, we investigate the kinetics and mechanism of the leaching of calcium aluminate slag in Na2CO3 solution for alumina recovery. The slag consists of leachable phases, e.g., 12CaO·7Al2O3, CaO·Al2O3, 5CaO·3Al2O3, and a non-leachable phase that contains Ca-Al-Si-Ti oxides. A series of leaching treatment is done at different temperatures, leaching times, stirring rates, Na2CO3 concentrations

Lithium carbonate precipitation from a Li2SO4 solution in a stirred crystallizer in semi-batch processes was investigated and compared using a heterogeneous CO2 reaction and homogeneous Na2CO3 reaction. Nucleation and crystal growth were successfully monitored by an inline Particle Track based on the focused beam reflectance measurement technique. The results obtained indicate that the particle size

The recovery of rhenium from acidic wash solution originating from a copper smelting process using sodium thiosulfate were investigated. Effects of reaction time, reaction temperature, flocculant addition and redissolubility of precipitate on the precipitation of rhenium have been studied. The temperature, Oxidation-Reduction Potential of the solution, reaction time in favor of the precipitation efficiency

Copper is the major impurity dissolved in silver electrorefining which potentially accumulates in the electrolyte during the process and co-deposits onto the cathode surface, decreasing the product quality. The study investigated the dissolution kinetics of copper in silver electrorefining as a function of wt%Cu in the industrial electrolyte ranges of 40–100 g/dm3 [Ag+], 5–15 g/dm3 [HNO3] and 20–60 g/dm3

The thermodynamics of ammonioalunite precipitation during the leaching of coal fly ash by ammonium hydrogen sulfate solution was studied, and it was found that ammonioalunite was formed above 448 K in the leaching system. Moreover, ammonioalunite was prepared by the hydrothermal synthesis method in an acid system, and its properties were investigated by X-ray diffraction (XRD) and field emission scanning

Mineral carbonation of serpentine in the aqueous phase traditionally required high temperatures and pressures or additives to dissolve the mineral. This was accompanied by significant costs and important environmental burdens. This paper aims to demonstrate the feasibility of thermally activated serpentine leaching under ambient temperature and pressure. A simulated cement flue gas effluent with a

In this study, the roles of tannic acid and gelatin in Zn electrowinning were investigated. The results indicated that the addition of 10 mg/L of gelatin promoted Zn electrowinning and increased its current efficiency (CE) from 89.55% to 91.8%. However, the CE was only 77.47% when the electrolyte contained 50 mg/L of gelatin. As the concentration of tannic acid in the electrolyte increased from 10 mg/L

For decades, methods for leaching scheelite based on the generation of soluble phosphotungstic heteropoly acids have been continuously studied. These methods can be performed under normal pressure and can achieve a high leaching ratio when treating scheelite, but their most obvious disadvantage is that the leaching speed is very slow when treating wolframite, which has limited their application in

The impacts of operational parameters on the morphological structure and uranium bioleaching performance of the bio-ore pellets obtained in one-step bioleaching by Aspergillus niger were investigated. The uranium recovery of over 80% was achieved under the optimized conditions. Furthermore, the morphological changes of ore particles before and after bioleaching were characterized by scanning electron

Presently, precipitation combined with roasting is commonly applied to produce rare earth oxide from rare earth chloride solution in industry, which has environmental hazards recognizably. In this study, a cleaner approach of cationic membrane electrolysis (CME) is presented and several rare earth oxides have been successfully prepared by this method, which proves its feasibility and also provides

The research presented contributes to the global goal of responsible production by providing robust tools for the optimization of gold dissolution in cyanide-free gold leaching solutions, which represent emerging non-toxic gold technologies. In the current study, gold dissolution was investigated in ferric and cupric chloride solutions. The effect of the redox potential on the open circuit potential