Showing papers in "Hydrometallurgy in 2003"

TL;DR: In this paper, Li and Co from LiCoO2 were leached over 95% with the addition of 1.7 vol.% H2O2 as a reducing agent.

TL;DR: In this paper, the authors present a methodology involving both the equilibrium and dynamic aspects of the metal biosorption process, which is most effectively done based on computer simulations utilizing mathematical models of the process.

TL;DR: In this article, a review of the leaching of gold with ammoniacal thiosulfate solutions is presented, and the current use and development of ion exchange resins for the recovery of gold and silver from such leach liquors.

TL;DR: In this article, an electrochemical study of chalcopyrite was performed, which included the elimination or dissolution of possible diffusion barriers formed on the mineral surface, and a study of possible causes that diminish the dissolution rate and inhibit the attack of this sulphide mineral.

TL;DR: In this article, the authors proposed a process to extract zinc from zinc ferrites contained in electric arc furnaces (EAF) dusts without destroying the iron oxide matrix, which can be recycled in the steel industry.

TL;DR: Preliminary data indicate that strains of Acidithiobacillus ferrooxidans, with a high amount of iron( III) ions in their extracellular polymeric substances, possess a higher oxidation activity than those with less iron(III) ions.

TL;DR: An alternative mechanism based on the application of simple chemical principles involving hydrated (hence realistic) solution species is proposed for the oxidative acid leaching of copper and iron from chalcopyrite.

TL;DR: In this article, a resolution to the debate is suggested based on the evidence of the kinetic studies that were performed, and the authors suggest that only kinetic studies can resolve the debate, since the critical factor is the kinetics of each proposed path.

TL;DR: An important role is suggested for previously unknown moderately acidophilic iron-oxidising bacteria in the bioremediation of acidic mine drainage waters, which is limited by the availability of nutrients.

TL;DR: In this paper, four derivatives of chitosan have been prepared by cross-linking and by grafting of sulfur compounds at different pHs in order to optimize the pH conditions at fixed chloride concentration.

TL;DR: In this paper, anionic metal complexes are very effectively bound by biomass types containing an abundance of amine groups and the biosorption mechanism was suspected to involve electrostatic attraction.

TL;DR: In this paper, the authors showed that the inhibition of ferrous iron oxidation activity by A. ferrooxidans observed at pH values above 3.0 is partially linked to the formation of ferric iron precipitates, which apparently hinder transport processes on the cell surface.

TL;DR: In this article, the growth characteristics of a strain of acidithiobacillus ferrooxidans isolated from mine water with ferrous ion, sulfur, or pyrite mineral as sole source of energy have been established.

TL;DR: In this article, a two-step leaching and solvent extraction method was proposed for the separation of copper and nickel from non-mounted printed wiring boards, which contained considerable amounts of heavy metals, such as copper, nickel and gold in metal strips printed on the resin substrates, while at the same time recovering solid flakes of gold in high purity.

TL;DR: In this paper, solvent extraction, stripping, electrowinning, precipitation and cementation experiments have been performed to recover valuable metals and regenerate the etching solution from the spent nitric etching solutions of printed circuit board (PCB).

TL;DR: In this article, a moving bed sand filter is used for the removal of biofilms formed on the sand grains after inoculation with heavy metal-resistant bacteria able to biosorb or to bioprecipitate heavy metals.

TL;DR: In this paper, low-grade nickeliferous laterites from the Sukinda region, Orissa, India, were characterized by microscopic investigations, using X-ray diffraction (XRD), DTA/TG, SEM and IR techniques.

TL;DR: In this article, the effect of various anions on the rate of copper(II) reduction was studied and inner sphere mechanisms were proposed for the reaction of copper (II) with thiosulfate, sulfite and trithionate.

TL;DR: Results suggest that bioleaching in the bubble column could be at least as efficient as in the stirred tank, and the single-strand conformation polymorphism technique proved to be an interesting and low-cost way to use molecular biology, which is worth developing in the field ofBioleaching.

TL;DR: In this article, a rough characterisation of biosorbent beads has been performed, and operating conditions for beads preparation aimed at biosorption have been optimised, and the equilibrium of the process was studied in order to determine the effect of pH and biomass concentration inside beads.

TL;DR: The solubilisation of copper in flasks inoculated with At.

TL;DR: The Tinto River (Huelva, southwestern Spain) is an extreme environment with a constant acidic pH (mean 2.3), a high concentration of heavy metals and a remarkable level of microbial diversity (bacteria, archaea, photosynthetic and heterotrophic protists, yeast and filamentous fungi) as mentioned in this paper.

TL;DR: In this article, the technical viability of the BRISA process (Biolixiviacion Rapida Indirecta con Separacion de Acciones: Fast Indirect Bioleaching with Actions Separation) for the copper recovery from chalcopyrite concentrates was proved.

TL;DR: In this article, a simultaneous leaching process to extract manganese and silver by one-step leaching in sulfuric acid solution in the presence of hydrogen peroxide is proposed.

TL;DR: In this paper, the effect of water salinity on the reactions occurring during pressure acid leaching of an arid-region laterite ore, using hypersaline water, seawater, sub-potable water and tap water, is examined.

TL;DR: In this paper, the effect of the most important parameters, the precipitation temperature, the sodium hydroxide concentration and the initial seed ratio (SR) in the solution, on the boehmite precipitation from supersaturated sodium aluminate solutions was developed.

TL;DR: In this paper, an alternative two-stage bio-leaching process was examined, in which the fungus was cultured in optimum conditions for active metabolite production and the spent medium was used as leaching agent.

TL;DR: In this paper, the stability constants for the formation of Cd(TPEN) 2+ and Zn 2+, which were measured by potentiometric titration technique, were evaluated as higher than 10 13.

TL;DR: In this article, a microbiological process using Pseudomonas mendocina MCM B-180 was developed for the removal of tellurite from solutions, which was transformed into metallic tellurium.

TL;DR: In this article, the rate of gold cementation on rotating copper discs was investigated in ammoniacal thiosulfate solutions as a function of rotational speed of the copper disc, initial gold concentration, initial copper concentration, and temperature.