Digestion of a laterite with sulfuric acid dissolves all constituents except silica. The resulting sulfatesaluminum sulfate, ferric sulfate, titanyl sulfate, and magnesium sulfateremain in solution at approximately 90 C. Hot filtration separates silica. Solution flow over iron reduces ferric sulfate to ferrous sulfate. Controlled ammonia addition promotes hydrolysis and precipitation of hydrated titania from titanyl sulfate that is removed by filtration. Addition of ammonium sulfate forms ferrous ammonium sulfate and ammonium aluminum sulfate solutions. Alum is preferentially separated by crystallization. Addition of ammonium bicarbonate to an ammonium alum solution precipitates ammonium aluminum carbonate which may be heated to produce alumina, ammonia, and carbon dioxide. The addition of oxalic acid generates insoluble ferrous oxalate which thermally decomposes to ferrous oxide and carbon monoxide which is used to reduce the ferrous oxide to metallic iron. Further oxalic acid addition precipitates magnesium oxalate which is thermally decomposed to magnesium oxide.

The present invention provides a method that is capable of selectively obtaining nickel and/or cobalt from an alloy, which contains copper. A method comprises: a leaching step S1 in which an alloy that contains copper as well as nickel and/or cobalt is subjected to a leaching treatment by means of an acid solution in the coexistence of a sulfurizing agent, thereby obtaining a leachate and a leaching residue; and a reduction step S2 in which a reducing agent is added to the thus-obtained leachate so as to reduce the leachate, thereby obtaining a post-reduction solution and a reduction residue. This method is characterized in that the reduction is carried out in the reduction step S2, while controlling the addition amount of the reducing agent so that the redox potential of the leachate is 0 mV or less as determined where a silver/silver chloride electrode is the reference electrode.

The invention relates to a method for reductive extraction of elemental noble metal from an acidic aqueous solution containing noble metal, the method comprising the addition of non-noble metal including zinc and/or tin to the acidic aqueous solution containing noble metal to form a reaction mixture, wherein the dissolved noble metal includes iridium, rhodium and/or ruthenium, wherein the non-noble metal is added in a leaner-than-stoichiometric amount, and wherein the pH of the acidic aqueous solution containing noble metal prior to the addition of the non-noble metal is in the range of +0.8 to +3.0 and is also kept in this range in the reaction mixture.

The invention relates to a method for reductive extraction of elemental noble metal from an acidic aqueous solution containing noble metal, the method comprising the addition of non-noble metal including zinc and/or tin to the acidic aqueous solution containing noble metal to form a reaction mixture, wherein the dissolved noble metal includes iridium, rhodium and/or ruthenium, wherein the non-noble metal is added in a leaner-than-stoichiometric amount, and wherein the pH of the acidic aqueous solution containing noble metal prior to the addition of the non-noble metal is in the range of +0.8 to +3.0 and is also kept in this range in the reaction mixture.

The presently disclosed concepts relate to green battery recycling systems and critical mineral reclamation and refinement. Alkali metal extraction (and in particular lithium extraction) is accomplished using a solid electrolyte membrane in combination with electrodes in a redox configuration. The energy used to initially extract lithium from a feed solution is stored as electrochemical energy, which electrochemical energy is reclaimed in subsequent reclamation processing steps. This reclamation may further allow for lithium to be converted to lithium carbonate or lithium hydroxide, or purified to a minimum purity of 99.9% lithium by mass. These extraction and reclamation steps may performed in continuous ultra-efficient ongoing cycles. Since irrecoverable energy losses incurred in each cycle are limited to negligible amounts of joule heating of the system components and feed solution, the system can be sustainably powered using locally-generated renewable energy, which in turn, provides for a green and sustainable solution for lithium recycling.

A method includes contacting a coal feedstock with an acidic solution to form residual coal and a leachate. The method further includes separating the residual coal from the leachate where the leachate contains rare earth elements and where the residual coal has preserved organic content and reduced inorganic content. Another method includes contacting a coal feedstock with a basic solution to form residual coal and a leachate. The method further includes separating the residual coal from the leachate where the leachate contains rare earth elements and where the residual coal has reduced inorganic content, but preserved organic content.

The invention relates to a method for concentrating metals, in particular silver and/or tin and/or lead from scrap containing metal, by treating the material/scrap containing silver and/or tin and/or lead with a sulfonic acid of the formula RSO.sub.2OH in the presence of an oxidizing agent, wherein R can be an organic group or ammonia.

The invention relates to a method for concentrating metals, in particular silver and/or tin and/or lead from scrap containing metal, by treating the material/scrap containing silver and/or tin and/or lead with a sulfonic acid of the formula RSO.sub.2OH in the presence of an oxidizing agent, wherein R can be an organic group or ammonia.

Provided is a method of recovering copper and one or more precious metals comprising leaching copper-bearing ore and/or concentrate under atmospheric or slightly pressurized conditions at a temperature below the boiling point of the leach solution in a sulfuric acidic solution in the presence of one or more alkali metal or alkali earth metal halides, whereby the total halide concentration is from 30 to 115 g/L, to dissolve copper and to obtain a leaching liquor comprising copper, sulfur species, and halides in solution. The leaching liquor is then subjected to a solid-liquid separation after which a first aqueous pregnant leach solution and a copper depleted leaching residue are obtained. Copper is purified by solvent extraction from the first aqueous pregnant leach solution to obtain a first copper-containing loaded organic solution and a first aqueous raffinate. The copper containing loaded organic solution is stripped and copper is recovered.

Provided is a method of recovering copper and one or more precious metals comprising leaching copper-bearing ore and/or concentrate under atmospheric or slightly pressurized conditions at a temperature below the boiling point of the leach solution in a sulfuric acidic solution in the presence of one or more alkali metal or alkali earth metal halides, whereby the total halide concentration is from 30 to 115 g/L, to dissolve copper and to obtain a leaching liquor comprising copper, sulfur species, and halides in solution. The leaching liquor is then subjected to a solid-liquid separation after which a first aqueous pregnant leach solution and a copper depleted leaching residue are obtained. Copper is purified by solvent extraction from the first aqueous pregnant leach solution to obtain a first copper-containing loaded organic solution and a first aqueous raffinate. The copper containing loaded organic solution is stripped and copper is recovered.