A method to produce a brine from mixed alum salts, the method comprising the steps of: (i) Dissolving or pulping alum salts (1) containing rubidium alum, cesium alum and/or potassium alum in water or a recycled liquor and adding a neutralising agent to precipitate (20) aluminium as aluminium hydroxide and some sulfate; (ii) Passing the product of step (i) to a solid liquid separation stage (21) to remove precipitated solids (5) from step (i); (iii) A decant or filtrate (6) from step (ii) is passed to a solvent extraction stage (24-27) whereby any contained cesium and rubidium is selectively extracted into the organic phase to form a loaded organic solution (16); (iv) Contacting the loaded organic solution (16) of step (iii) with a scrub solution (17), which is at a pH lower than the extraction pH, to effectively scrub co-loaded potassium from the organic phase; (v) Contacting the scrubbed organic (19) of step (iv) with formic acid (20) to strip cesium and rubidium from the organic, the stripped cesium and rubidium forming a cesium and/or rubidium sulfate brine (21); and (vi) Recycling the stripped organic (22) of step (v) to the extraction stage (24-27).

A process for recovering chromium from hexavalent chromium-containing wastewater comprises the following steps: (1) extracting hexavalent chromium in wastewater to an organic phase by using an extracting agent, and separating hexavalent chromium from a water phase, so as to acquire a hexavalent chromium-loaded organic phase; (2) reducing the hexavalent chromium-loaded organic phase by using an aqueous solution of an organic reducing agent, reducing hexavalent chromium into trivalent chromium, reversely extracting trivalent chromium into the water phase, and separating the organic phase from the water phase to acquire a solution of the trivalent chromium and a renewable organic phase, wherein the organic reducing agent is one or a mixture of alcohols, aldehydes and carboxylic acids having the carbon atom number ranging 1 to 3; and (3) performing solvent evaporation on the solution of trivalent chromium, catalyzing, and recovering the trivalent chromium.

The extraction system contains secondary amides and alkyl alcohols which are separately used as the extractants for extracting lithium and boron and consist of a single compound or a mixture of two or more compounds, and the total number of carbon atoms in their molecules are 12˜18 and 8˜20 respectively; the extraction system has a freezing point less than 0° C. With a volume ratio of an organic phase and a brine phase being 1˜10:1, at a brine density of 1.25˜1.38 g/cm.sup.3, at a brine pH value of 0˜7 and at a temperature of 0˜50° C., a single-stage or multi-stage countercurrent extraction and a stripping are conducted to obtain a water phase with a low magnesium-lithium ratio, which is subjected to concentration, impurity removal and preparation to get lithium chloride, lithium carbonate, lithium hydroxide and boric acid respectively. Water is used for stripping, greatly reducing the consumption of acid and base.

A method for recovering a valuable material from a perovskite solar cell includes immersing a perovskite solar cell device in an organic solvent to dissolve a monovalent metal cation, a divalent metal cation, and two halogen anions in the organic solvent, followed by adding an oxidizing agent and conducting a heating treatment to form a solid phase residue and a halogen molecule, dissolving the halogen molecule in deionized water to form a halogen solution, rinsing the solid phase residue with deionized water to obtain a solid phase and a liquid phase, calcining the solid phase into a metal oxide, or mixing the solid phase with the halogen solution to obtain a first metal halide, subjecting the liquid phase to an extraction treatment to form an oil phase layer, followed by conducting a back-extraction treatment, adding the halogen solution, and conducting a vacuum concentration treatment to obtain a second metal halide.

A process for recovering chromium from hexavalent chromium-containing wastewater comprises the following steps: (1) extracting hexavalent chromium in wastewater to an organic phase by using an extracting agent, and separating hexavalent chromium from a water phase, so as to acquire a hexavalent chromium-loaded organic phase; (2) reducing the hexavalent chromium-loaded organic phase by using an aqueous solution of an organic reducing agent, reducing hexavalent chromium into trivalent chromium, reversely extracting trivalent chromium into the water phase, and separating the organic phase from the water phase to acquire a solution of the trivalent chromium and a renewable organic phase, wherein the organic reducing agent is one or a mixture of alcohols, aldehydes and carboxylic acids having the carbon atom number ranging 1 to 3; and (3) performing solvent evaporation on the solution of trivalent chromium, catalyzing, and recovering the trivalent chromium.

The present disclosure relates to the use of a catalyst comprising a thiocarbonyl group and a cosolvent in a method for extracting a base metal from a material comprising the base metal. The method may comprise contacting a material with a catalyst comprising a thiocarbonyl and a cosolvent system, wherein the cosolvent system comprises a solvent and a cosolvent. The method may comprise hydrometallurgical extraction.

A method is disclosed for recovering gold from a gold-containing organic solution containing soluble gold. The method comprises contacting the gold-containing organic solution with an aqueous stripping solution in order to extract gold from the gold-containing organic solution into the aqueous stripping solution. The aqueous stripping solution containing gold is separated from the organic solution. The separated aqueous stripping solution containing gold is contacted with a reducing agent containing sodium metabisulphite, in order to reduce gold from the aqueous stripping solution.

The present invention relates to a process for efficiently enriching and recovering noble metals of platinum and palladium based on solvent extraction, wherein isoamyl alcohol is used as extracting agent and 2-methoxyphenyl thiourea is used as extraction-assisted complexing agent. 2-methoxy-phenyl thiourea is added to aqueous phase to react with platinum and palladium, and isoamyl alcohol is used as extracting agent to extract the organic phase, thus realizing the purpose of separating and extracting noble metals from base metals while enriching noble metals of platinum and palladium. The present invention, which can not only realize the separation of noble metals and base metals, but also enhance the enrichment and recovery ratios of noble metals of platinum and palladium, with low cost reagents, small influence on the environment and simple technical process, thus is a new and efficient extraction and enrichment system for noble metals.

A method is disclosed for recovering gold from a gold-containing organic solution containing soluble gold. The method comprises contacting the gold-containing organic solution with an aqueous stripping solution in order to extract gold from the gold-containing organic solution into the aqueous stripping solution. The aqueous stripping solution containing gold is separated from the organic solution. The separated aqueous stripping solution containing gold is contacted with a reducing agent containing sodium metabisulphite, in order to reduce gold from the aqueous stripping solution.

A method for recovering a valuable material from a perovskite solar cell includes immersing a perovskite solar cell device in an organic solvent to dissolve a monovalent metal cation, a divalent metal cation, and two halogen anions in the organic solvent, followed by adding an oxidizing agent and conducting a heating treatment to form a solid phase residue and a halogen molecule, dissolving the halogen molecule in deionized water to form a halogen solution, rinsing the solid phase residue with deionized water to obtain a solid phase and a liquid phase, calcining the solid phase into a metal oxide, or mixing the solid phase with the halogen solution to obtain a first metal halide, subjecting the liquid phase to an extraction treatment to form an oil phase layer, followed by conducting a back-extraction treatment, adding the halogen solution, and conducting a vacuum concentration treatment to obtain a second metal halide.