A plurality of different metals, including precious metals, platinum group metals, rare earth elements, alkaline earth metals, etc., can be electrochemically recovered from waste materials such as ashes and e-waste, e.g., printed circuit boards. Waste feed stocks are treated with supercritical CO.sub.2 (scCO.sub.2) and acid to produce a solid delaminated waste and a liquid delaminated waste for recovery of elemental metals and metal compounds from each. Carbonation reactions can be used to convert and recover alkaline earth metals from the liquid delaminated waste. The solid delaminated waste can yield a solid gold product, and be further treated along with the liquid delaminated waste via a solvent including one or more organic ligands that bind target metals to form metal-ligand complexes. Electrochemical separation of the different metals, e.g., via stepwise variation of pH to release the metals from organic ligands having different pKa values, yields high purity metal product streams.

A method and system are provided for the creation of vertical and horizontal freeze wells, in a dome-like pattern around the ore body, as a hydraulic barrier to ensure the ISR mining solution and the mined minerals do not flow out of the ore body. A method to formulate a suitable mining solution used for ISR mining, where the lixivant does not freeze when using the freeze dome containment method and where the resulting PLS has a high concentration of dissolved minerals and thus eliminates the need for the solvent extraction/ion exchange step during processing is also described.

A method and system are provided for the creation of vertical and horizontal freeze wells, in a dome-like pattern around the ore body, as a hydraulic barrier to ensure the ISR mining solution and the mined minerals do not flow out of the ore body. A method to formulate a suitable mining solution used for ISR mining, where the lixivant does not freeze when using the freeze dome containment method and where the resulting PLS has a high concentration of dissolved minerals and thus eliminates the need for the solvent extraction/ion exchange step during processing is also described.

Formation of CaSO.sub.4 and Fe.sub.2O.sub.3 containing deposits is reduced in a pressure oxidation autoclave and/or adjacent circuits during pressure oxidation of gold-containing ore. The gold-containing ore is combined with water to create an aqueous slurry that is heated and introduced into the autoclave. The method includes providing a scale inhibitor that is free of an organic polymer and includes an inorganic phosphate according to formula (I), (XPO.sub.3).sub.m, wherein X is Na, K, H, or combinations thereof, and m is at least about 6, an inorganic phosphate according to formula (II), Y.sub.n+2P.sub.nO.sub.3n+1, wherein Y is Na, K, H, an organic phosphonate; or combinations thereof, and n is at least about 6. The method includes the step of combining the scale inhibitor and at least one of the gold-containing ore, the water, and the aqueous slurry to reduce scale.

Provided is a method for separating lithium from a lithium solution containing lithium by 200 mg/L or more and fluorine by 20 mg/L or more, the method including: a first removal step of adding a first component, which solidifies the fluorine contained in the lithium solution, to the lithium solution and removing the fluorine solidified to obtain a F-removed liquid; and a second removal step of adding a second component, which solidifies the first component remaining in the F-removed liquid, to the F-removed liquid and removing the first component solidified to obtain a first component-removed liquid.

The present disclosure relates to a method for lithium recovery by extraction-stripping separation and purification, including: (1) performing an extraction on a lithium-containing solution using an extraction system including a composite extractant at a pH in a range of 10-13 and separating to obtain a lithium-loaded organic phase; (2) subjecting the lithium-loaded organic phase obtained in step (1) to a gas-liquid-liquid three-phase stripping to obtain a lithium-loaded stripping solution; and (3) subjecting the stripping solution obtained in step (2) to a thermal treatment and separating to obtain a lithium product and a separated mother liquor.

The present disclosure relates to a method for lithium recovery by extraction-stripping separation and purification, including: (1) performing an extraction on a lithium-containing solution using an extraction system including a composite extractant at a pH in a range of 10-13 and separating to obtain a lithium-loaded organic phase; (2) subjecting the lithium-loaded organic phase obtained in step (1) to a gas-liquid-liquid three-phase stripping to obtain a lithium-loaded stripping solution; and (3) subjecting the stripping solution obtained in step (2) to a thermal treatment and separating to obtain a lithium product and a separated mother liquor.

Pyro-hydrometallurgical methods are described to economically and environmentally recover a target metal from iron slag or steel slag. For instance, the method can enable subjecting an iron or steel slag feed to acid-baking with an acid to produce a dried mixture comprising at least one soluble metal salts, then subjecting the dried mixture to water leaching to an aqueous solution comprising an aqueous leachate rich in said target metal and solid residues and subsequently separating the aqueous leachate rich in said target metal from the solid residues. This acid-baking water-leaching method facilitates efficient recovery of target metal compared to conventional methods.

A method for extracting base and precious metals, all contained in refractory minerals, using aqueous media. The method includes mixing the mineral (Cu2S, CuS, CuFeS2, Cu5FeS4, FeS2, FeAsS.NiS, (Ni,Fe)xSy), ground to an appropriate size (2.5 centimetres), with a specific dose of solid reagent in a rotary agglomeration drum and then adding slightly acidified water to obtain a defined water content (5-8%) depending on the type of gangue contained in the metal-containing solid, thereby forming an agglomerate that will form a heap, which is subsequently allowed to stand for a period of several days (20-60 days), during which the conditions required to transform the refractory matrix into a highly soluble solid will be generated. Finally, appropriately regulated irrigation is applied, thus resulting in extraction of the metal by simple aqueous washing.

In embodiments, pressurized fluid containing reagents of formulated mixtures of solids, liquids and gasses are delivered into a cased well then into the heap or pile to open or stimulate new horizontal and vertical fluid pathways, channels, plus drains from the open bottom of the well to the bottom of the heap or pile for fluid collection. This delivery method may also drain any fluids that are retained and pooled in the heap or pile. The removal of pooled fluids will increase the inter-particle cohesion and friction in the heap or pile, thus adding geotechnical stability and resistance to movement of the heap or pile. The cased wells may also add shear strength to the collective to retard movement of the heap or pile.