A stabilization process for an arsenic solution comprising thiosulfates, the process comprising: acidifying the arsenic solution to decompose the thiosulfates, to yield an acidified solution; oxidizing the acidified solution to oxidize residual As.sup.3+ to As.sup.5+ and reduced sulfur species to sulfates, to yield a slurry comprising elemental sulfur; separating elemental sulfur from the slurry to yield a liquid; oxidizing the liquid to oxidize residual reduced sulfur species, to yield an oxidized solution; and forming a stable arsenic compound from the oxidized solution.

A process for extraction of copper from an arsenical copper sulfide concentrate is provided. The process includes atmospheric oxidative leaching of a feed slurry including the arsenical copper sulfide concentrate and an acidic iron sulfate-containing leach solution, in the presence of oxygen, to produce a leach slurry including copper and arsenic dissolved into the leach solution. After dissolving the copper and arsenic, and before precipitating the arsenic dissolved during the oxidative leaching, pre-precipitation solids are recovered from the leach slurry to produce the pre-precipitation solids and a resulting pregnant leach solution including the copper and arsenic. Scorodite-containing seed is introduced to the pregnant leach solution including the copper and arsenic to induce precipitation of the arsenic dissolved during the oxidative leaching, as scorodite. Solids are recovered from the pregnant leach solution to produce the solids, including the scorodite, and an arsenic-reduced pregnant leach solution including the copper. The arsenic-reduced pregnant leach solution including the copper is subjected to solvent extraction for recovering copper and thereby producing a raffinate including sulfuric acid and iron sulfate, and at least a portion of the raffinate including the sulfuric acid and iron sulfate is recycled to the oxidative leaching.

The subject invention provides safe, environmentally-friendly, compositions and methods for extracting minerals and/or metals from ore. More specifically, the subject invention provides for bioleaching using a composition comprising one or more biosurfactant-producing microorganisms and/or microbial growth by-products. In specific embodiments, the composition comprises biosurfactant-producing yeasts and/or their growth by-products.

A bioleaching and solvent extraction process with selective recovery of copper and zinc from polymetallic sulphide concentrates is described, comprising a bioleaching and ferric ion reducing process and a copper and zinc solvent extraction process. The bioleaching and ferric ion reducing process comprises a concentrates pulp conditioning step; a bioleaching step, wherein once the pulp is conditioned it is subjected to a bioleaching process using a plurality of bioreactors of the stirred-tank type with an air injection and diffusion system, which allows handling of a pulp density higher than 15%; a step of solid separation from a solution rich in metallic ions from the bioleaching step; and, a ferric ion reduction step, wherein the pulp from the previous step is subjected to a transformation step of ferric ions into ferrous ions. The solvent extraction step comprises a copper solvent extraction and electrolysis step; an arsenic control step, wherein arsenic is controlled in the solution once copper has been extracted from it; and, a zinc solvent extraction and electrolysis step, which uses a phosphinic acid-based zinc extraction dissolution.

A method of leaching copper-containing ores, such as chalcopyrite ores, with a leach liquor in the presence of silver and an activation agent that activates silver whereby the silver enhances copper extraction from copper ores.

Various embodiments provide a leaching solution monitoring module comprising a first leaching solution distribution system interface, a flow meter in fluid communication with the first leaching solution distribution system interface, the flow meter in fluid communication a 3-way pressure regulator, and a second leaching solution distribution system interface in fluid communication with the 3-way pressure regulator.

The invention relates to an improved method for the preparation of alkylsalicylaldehyde or its corresponding metallic salts. The invention also relates to a method for the preparation of alkylsalicylaldoxime by reacting said alkylsalicylaldehyde or its corresponding metallic salts with hydroxylamine or its salt. The invention also relates to a method for extracting a metal in an aqueous solution containing dissolved metal.

Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.

A method of leaching chalcopyrite ores includes the steps of forming agglomerates of fragments of chalcopyrite ores and silver and leaching the agglomerates with suitable leach liquor.

Various embodiments provide a leaching solution monitoring module comprising a first leaching solution distribution system interface, a flow meter in fluid communication with the first leaching solution distribution system interface, the flow meter in fluid communication a 3-way pressure regulator, and a second leaching solution distribution system interface in fluid communication with the 3-way pressure regulator.