Alkaline oxidation process for treating refractory sulfide ore or concentrate particles enriched in a metal to be recovered comprising stages in which refractory ore or concentrate particles are surface-oxidized in an alkaline oxidation step in alkaline liquid phase with calcium hydroxide forming an alkaline slurry, which slurry is thereafter mechanically activated to remove passivating coatings from the surface oxidized refractory ore particles.

An improved method for recovering metals from spent catalysts, particularly from spent slurry catalysts, is disclosed. The method and associated processes comprising the method are useful to recover spent catalyst metals used in the petroleum and chemical processing industries. The method generally involves a combination of a pyrometallurgical and a hydrometallurgical method and includes forming a potassium carbonate calcine of a KOH leach residue of the spent catalyst containing an insoluble Group VIIIB/Group VIB/Group VB metal compound combined with potassium carbonate, and extracting and recovering soluble Group VIB metal and soluble Group VB metal compounds from the potassium carbonate calcine.

A process for treating minerals containing metal sulphide and a precious metal, the process comprising fine grinding the minerals and subjecting the minerals to a first leaching step conducted under oxidising conditions at a pH of from 5 to 7, and subjecting a pulp or suspension or solid residue from the first leaching step to a second leaching step conducted under oxidising conditions at a pH of at least 9.0.

A process for recovery of one or more elements, selected from precious metals and chalcophile metals, as herein defined, from materials containing precious and/or chalcophile metal/s, said process including: (i) contacting the material with an alkaline solution containing a lixiviant comprising an amino acid, or derivative thereof, and an alkali stable transition metal complex in order to form a leachate containing the precious metal and/or chalcophile metal; and (ii) recovering the precious metal and/or chalcophile metal from the leachate.

A process for the recovery of gold from carbon fines waste, which are produced, especially from carbon-in-leach (CIL) and carbon-in-pulp (CIP) processes. The gold may be eluted from carbon fines with alkaline eluent having a low oxidation reduction potential (ORP). Value added products may be obtained from the extracted carbon fines.

A process for the recovery of gold from carbon fines waste, which are produced, especially from carbon-in-leach (CIL) and carbon-in-pulp (CIP) processes. The gold may be eluted from carbon fines with alkaline eluent having a low oxidation reduction potential (ORP). Value added products may be obtained from the extracted carbon fines.

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.

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.

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.