Abstract: A method for producing metal zinc by liquid/liquid extraction, comprising leaching of a zinc-bearing solid raw material containing antimony with a slightly acid aqueous solution, at a pH value maintained above 3 and less than or equal to 5, with formation of a suspension, drawing-off from the suspension of an aqueous phase containing zinc in solution to be subject to the extraction, additional leaching of the remaining suspension with an acid aqueous solution, at a pH value maintained below 3.5 and greater than or equal to 1, with formation of a pulp, introduction of a neutralizing agent in this pulp with coprecipitation of antimony and other impurities and separation from this neutralized pulp of a zinc-bearing aqueous solution which is recycled to the step for leaching the zinc-bearing solid raw material.

Abstract: Processes for metal leaching/solvent extraction are described which comprise: (a) providing a first aqueous leach pulp which comprises a mixture of leached solids and an aqueous leach solution comprising a metal, a leaching agent and water; (b) subjecting the first aqueous leach pulp to a first solid-liquid separation to provide a first clarified aqueous leach solution and a second aqueous leach pulp, wherein the second aqueous leach pulp comprises the leached solids at a % solids level greater than the first pulp; (c) subjecting the first clarified aqueous leach solution to a first solvent extraction prior to any significant dilution, whereby a first aqueous raffinate is obtained; (d) subjecting the second aqueous leach pulp to a second solid-liquid separation with dilution via an aqueous stream to obtain a second clarified aqueous leach solution; and (e) subjecting the second clarified aqueous leach solution to a second solvent extraction whereby a second is aqueous raffinate is obtained.

Abstract: The invention relates to a process involving the following steps: a) performing leaching of the raw material with an acid aqueous solution to dissolve the zinc if said raw material is a solid; b) optionally performing solid-liquid separation; c) neutralizing the aqueous solution once the zinc-containing raw material is in liquid form; d) performing solid-liquid separation of the solution rich in zinc from the solids precipitated during the neutralization step; e) extracting the zinc using an acid organic solvent; f) purifying the organic solvent from the extraction step; g) re-extracting zinc from the organic solvent using an acid aqueous solution; h) recovering the zinc by electrolysis and/or crystallization and/or precipitation.

Abstract: A method of extracting zinc from a sulphidic ore is provided which comprises bioleaching the ore in a heap with acidophilic microorganisms to produce a pregnant leach solution which is recovered from the bottom of the heap. An integrated process which comprises subjecting the pregnant leach solution to neutralization and solvent extraction to produce a concentrated zinc solution is also provided. Zinc may be recovered from the concentrated solution by means of electrowinning, either in the absence or presence of manganese. Alternatively zinc may be recovered in the form of a zinc compound.

Abstract: A processs for the recovery of zinc from a zinc sulphide ore or concentrate comprises the steps of subjecting the concentrate to pressure leaching with an acidic solution containing at least about 15 g/L iron in solution to produce a zinc solution and a solid leach residue containing iron. The zinc solution is subjected to zinc solvent extraction to produce a raffinate and a pregnant zinc solution. A method of removing ion from an iron bearing raffinate is also provided which comprises pressure leaching a zinc sulphide ore with the iron bearing raffinate to produce a solid leach residue containing iron and a zinc solution.

Abstract: Improved methods are disclosed for the efficient and cost-effective recovery of zinc metal from zinc-containing brines. Zinc is first bound to an anionic ion exchange resin (IX) which has been equilibrated with a solution containing a reducing agent, washed, and eluted with an elution solution. A reducing agent can be added to the brine prior to loading on the IX and can optionally be added to the IX after the washing step. The eluted zinc is extracted with a water-immiscible cationic organic solvent (SX), which is scrubbed, then stripped with concentrated acid. Substantially pure zinc is recovered by electrowinning the zinc-loaded concentrated acid solution.

Abstract: An improved process for the extraction of a metal from an aqueous ammoniacal solution comprising: (i) contacting the aqueous ammoniacal solution with an extraction reagent comprised of a water insoluble extractant for the metal, to provide an organic phase, now containing metal values, and an aqueous phase from which metal values have been extracted; (ii) contacting the organic phase with an aqueous stripping solution to provide an aqueous strip phase, now containing metal values, and an organic phase from which metal values have been stripped; and (iii) recovering the metal values from the aqueous stripping solution; the improvement wherein (a) the extraction reagent contains an ammonia antagonist having only hydrogen bond acceptor properties; (b) the stripping solution is an aqueous highly acidic solution; and (c) the organic phase is washed with a weakly acidic aqueous solution prior to stripping with the highly acidic aqueous stripping solution.

Abstract: The present invention is directed to a process for removing various contaminants (e.g., organic collectors, contaminant metals or spectator ions, and/or suspended and colloidal solids) from process streams in leaching processes. The contaminant removal is performed by one or more membrane filtration systems (e.g., nanofilters, ultrafilters, and/or microfilters) treating process streams including, the pregnant leaching solution, the barren raffinate, and the lean and rich electrolytes.