A process for leaching minerals that contain metal sulphides and one or more precious metals or precious metal compounds, the process comprising the steps of a first leaching step to leach the minerals under oxidative conditions at a pH of less than 4 to form a slurry or pulp, the slurry or pulp comprising a solid phase containing unreacted components, solid reaction products and elemental sulphur, and subjecting the slurry or pulp or solid residue from the first leaching step to a second leaching step comprising oxidative leaching at pH of at least 9.0 to thereby form thiosulphate, whereby the thiosulphate leaches precious metal from the solid residue.

A process for leaching minerals that contain metal sulphides and one or more precious metals or precious metal compounds, the process comprising the steps of a first leaching step to leach the minerals under oxidative conditions at a pH of less than 4 to form a slurry or pulp, the slurry or pulp comprising a solid phase containing unreacted components, solid reaction products and elemental sulphur, and subjecting the slurry or pulp or solid residue from the first leaching step to a second leaching step comprising oxidative leaching at pH of at least 9.0 to thereby form thiosulphate, whereby the thiosulphate leaches precious metal from the solid residue.

Systems and methods using solar evaporation to preconcentrate lithium containing brines to at or near lithium saturation, followed by a separation processes to separate lithium from impurities. A separated impurity stream is recycled to a point in the evaporation sequence where conditions are favorable for their precipitation and removal or disposed in a separate evaporation pond or reinjected underground, while a lower impurity stream is transferred to one or more of the removal location, to a subsequent pond in the sequence, or to a lithium plant or concentration facility. Further concentration of lithium by evaporation can then take place because impurities are removed thus eliminating lithium losses due to co-precipitation and achieving significantly higher concentrations of lithium.

Systems and methods using solar evaporation to preconcentrate lithium containing brines to at or near lithium saturation, followed by a separation processes to separate lithium from impurities. A separated impurity stream is recycled to a point in the evaporation sequence where conditions are favorable for their precipitation and removal or disposed in a separate evaporation pond or reinjected underground, while a lower impurity stream is transferred to one or more of the removal location, to a subsequent pond in the sequence, or to a lithium plant or concentration facility. Further concentration of lithium by evaporation can then take place because impurities are removed thus eliminating lithium losses due to co-precipitation and achieving significantly higher concentrations of lithium.

Processes and methods for refining ferronickel alloy, and producing nickel sulfate or other nickel product, are provided, where the ferronickel alloy is treated with an oxidizing leach. The oxidizing leach may be, for example, a pressure oxidation (POX) leach or a leach with peroxide or copper (II) ions. The treatment may be in the presence of added copper, such as by providing a copper sulfate solution. Producing nickel sulfate may comprise removing copper and iron after the leach, removing impurities, and either crystallizing the nickel sulfate or precipitating/winning another nickel product.

Despite the abundance of scandium, its commercial applications continue to be limited by the absence of reliable, secure, stable and long-term production. The subject-matter disclosed herein provides for a method for extracting Rare Earth Elements (REE), scandium and/or Rare-Earth Oxides (REO) from ore and mineral concentrates, the method comprising: providing Rare Earth Elements (REE) and/or scandium bearing feedstock; a high-pressure caustic (HPC) leaching step, comprising leaching the feedstock in an alkali solution at a first temperature for a target period of time and at a given pressure to produce a leachate slurry; extracting a solid residue from the leachate slurry; leaching of the solid residue in a mineral acid to form a primary leach solution; extracting scandium and/or REE from the primary leach solution; and/or precipitating REE remaining in the raffinate to form a mixed REE-carbonate to thereby facilitate the extraction of REO.

In alternative embodiments, provided are methods and processes for the removal of cadmium (Cd) from wet-process phosphoric acid that may contain Cd, including excessive amounts of Cd. The process developed is based on the application of commercially available ion exchange resins with the application of Continuous Ion Exchange (CIX) technology. In alternative embodiments, provided are processes and methods for the recovery and/or the removal of cadmium from wet-process phosphoric acid using a continuous ion exchange approach. In alternative embodiments, use of processes and methods as provided herein allows for the reduction of cadmium metal contaminants with minimal phosphate losses and dilution in order to produce a phosphoric acid that is suitable for the production of fertilizers and phosphoric acid products, such as world-class diammonium phosphate fertilizer (DAP), merchant-grade phosphoric acid, super-phosphoric acid, and other phosphoric acid products.

In alternative embodiments, provided are methods and processes for the removal of cadmium (Cd) from wet-process phosphoric acid that may contain Cd, including excessive amounts of Cd. The process developed is based on the application of commercially available ion exchange resins with the application of Continuous Ion Exchange (CIX) technology. In alternative embodiments, provided are processes and methods for the recovery and/or the removal of cadmium from wet-process phosphoric acid using a continuous ion exchange approach. In alternative embodiments, use of processes and methods as provided herein allows for the reduction of cadmium metal contaminants with minimal phosphate losses and dilution in order to produce a phosphoric acid that is suitable for the production of fertilizers and phosphoric acid products, such as world-class diammonium phosphate fertilizer (DAP), merchant-grade phosphoric acid, super-phosphoric acid, and other phosphoric acid products.

A method for extracting copper values from a low grade copper ore feedstock is provided. The method includes (a) providing an ore feedstock of a copper oxide ore; (b) subjecting the ore to at least one process selected from the group consisting of primary crushing processes and secondary crushing processes; (c) subjecting the ore feedstock to high pressure grinding roll crushing, thereby obtaining a crushed ore; (d) subjecting the crushed ore to acid curing, thereby obtaining a cured ore; (e) subjecting the cured ore to vat or heap leaching, thus yielding a leachate; (f) passing the leachate through a first ion exchange resin which is selective to base metals plus copper, thereby removing a portion of the copper values from the leachate and yielding a first loaded resin and a first treated leachate; (g) stripping base metals plus copper values from the first loaded resin with a first stripping solution, thereby yielding a base metals plus copper-loaded stripping solution; (h) selectively extracting copper values from the copper-loaded stripping solution via solvent extraction, thereby obtaining an extract and a raffinate; and (i) crystallizing a copper salt from the extract, thereby obtaining a crystallized copper salt.

A method for extracting copper values from a low grade copper ore feedstock is provided. The method includes (a) providing an ore feedstock of a copper oxide ore; (b) subjecting the ore to at least one process selected from the group consisting of primary crushing processes and secondary crushing processes; (c) subjecting the ore feedstock to high pressure grinding roll crushing, thereby obtaining a crushed ore; (d) subjecting the crushed ore to acid curing, thereby obtaining a cured ore; (e) subjecting the cured ore to vat or heap leaching, thus yielding a leachate; (f) passing the leachate through a first ion exchange resin which is selective to base metals plus copper, thereby removing a portion of the copper values from the leachate and yielding a first loaded resin and a first treated leachate; (g) stripping base metals plus copper values from the first loaded resin with a first stripping solution, thereby yielding a base metals plus copper-loaded stripping solution; (h) selectively extracting copper values from the copper-loaded stripping solution via solvent extraction, thereby obtaining an extract and a raffinate; and (i) crystallizing a copper salt from the extract, thereby obtaining a crystallized copper salt.