A method for recovery of gold from gold-containing materials, such as electronic waste material, minerals and sands is described. The method includes crushing the gold containing material to obtain a particulate material. The particulate material is then preheated in an oxygen-containing gas environment in a preheating zone. The method also includes mixing the oxidized particulate material with a chlorine-containing material and treating the mixture in a reaction zone. The treatment is carried out by heating the mixture to provide thermal decomposition of the chlorine-containing material and produce a chlorine-containing gas mixture, and by applying an electromagnetic field to the chlorine-containing gas mixture to provide ionization of chlorine. A volatile gold-containing chloride product, produced in the reaction zone as a result of a chemical reaction between gold and chlorine ions, is then cooled to convert the volatile gold-containing chloride product into solid phase gold-containing materials.

A method for recovery of gold from gold-containing materials, such as electronic waste material, minerals and sands is described. The method includes crushing the gold containing material to obtain a particulate material. The particulate material is then preheated in an oxygen-containing gas environment in a preheating zone. The method also includes mixing the oxidized particulate material with a chlorine-containing material and treating the mixture in a reaction zone. The treatment is carried out by heating the mixture to provide thermal decomposition of the chlorine-containing material and produce a chlorine-containing gas mixture, and by applying an electromagnetic field to the chlorine-containing gas mixture to provide ionization of chlorine. A volatile gold-containing chloride product, produced in the reaction zone as a result of a chemical reaction between gold and chlorine ions, is then cooled to convert the volatile gold-containing chloride product into solid phase gold-containing materials.

The invention relates to a method for recovering precious metals from electronic waste utilising biometallurgical techniques. In one aspect, a method of recovering one or more target metals from electronic waste, includes (a) removing at least a portion of non-target material from the electronic waste or grinding to a preselected size particle to give pre-processed electronic waste; (b) contacting the pre-processed electronic waste with a lixiviant such that at least a portion of the target metal(s) dissolve into the lixiviant to produce a pregnant solution; (c) contacting a microorganism with the pregnant solution such that at least a portion of the target metal(s) ions biosorb to the microorganism wherein the microorganism becomes metal laden and the pregnant solution becomes barren; (d) substantially separating the metal laden microorganism from the barren solution; and (e) recovery of the target metal(s) from the metal laden microorganism.

The present invention relates to a method for extracting base and precious metals, all contained in refractory minerals, using aqueous media. The aim is to replace the current flotation/smelting-method for extracting minerals in Chilean and global mining or classical leaching with a method comprising a simple and robust pre-treatment that leads to solubilisation of the refractory matrices thereof. The method consists of 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 essence, the method achieves maximum transformation of the original refractory mineral into a highly soluble solid salt during a step prior to the conventional leaching process. Thus, the metal will be contained in a solid with a much higher solubility than the original matrix, therefore the dissolution thereof will be faster, more efficient and require a minimal use of consumables and reagents.

The present invention relates to a method for extracting base and precious metals, all contained in refractory minerals, using aqueous media. The aim is to replace the current flotation/smelting-method for extracting minerals in Chilean and global mining or classical leaching with a method comprising a simple and robust pre-treatment that leads to solubilisation of the refractory matrices thereof. The method consists of 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 essence, the method achieves maximum transformation of the original refractory mineral into a highly soluble solid salt during a step prior to the conventional leaching process. Thus, the metal will be contained in a solid with a much higher solubility than the original matrix, therefore the dissolution thereof will be faster, more efficient and require a minimal use of consumables and reagents.

A method and a system for gold and silver recovery from a pregnant solution resulting from gold extraction from an ore using halogen, the method comprising lowering the oxidation reduction potential of the pregnant solution by mixing the pregnant solution with a reducer over the surface of a bed of silica, and flowing the mixture through the bed of silica. The system comprises a bed of silica, a feeder controlling feeding of the pregnant solution with a reducer to direct a mixture of an ORP less than 550 mV to the surface of the bed of silica, and a collector receiving a barren solution from the bed of silica after flowing of the mixture therethrough.

A method and a system for gold and silver recovery from a pregnant solution resulting from gold extraction from an ore using halogen, the method comprising lowering the oxidation reduction potential of the pregnant solution by mixing the pregnant solution with a reducer over the surface of a bed of silica, and flowing the mixture through the bed of silica. The system comprises a bed of silica, a feeder controlling feeding of the pregnant solution with a reducer to direct a mixture of an ORP less than 550 mV to the surface of the bed of silica, and a collector receiving a barren solution from the bed of silica after flowing of the mixture therethrough.

Provided is a process for recovery of gold from gold-bearing raw materials comprising (a) leaching said gold-bearing raw material in a chloride containing leaching solution containing a total concentration of less than 120 g/L of halide ions, whereby the total concentration of chloride ions is less than 120 g/L of to dissolve gold and to obtain a leach solution comprising gold in solution; and simultaneously contacting the leach solution comprising gold in solution with a re-sorptive material to obtain a leach solution comprising gold-bearing re-sorptive material; and (b) recovering gold and optionally silver from the said gold-bearing re-sorptive material.

Provided is a process for recovery of gold from gold-bearing raw materials comprising (a) leaching said gold-bearing raw material in a chloride containing leaching solution containing a total concentration of less than 120 g/L of halide ions, whereby the total concentration of chloride ions is less than 120 g/L of to dissolve gold and to obtain a leach solution comprising gold in solution; and simultaneously contacting the leach solution comprising gold in solution with a re-sorptive material to obtain a leach solution comprising gold-bearing re-sorptive material; and (b) recovering gold and optionally silver from the said gold-bearing re-sorptive material.

The disclosure provides a method of producing a platinum colloid comprising reducing platinum ions by the use of a platinum ion solution, water, a nonionic surfactant, a pH adjusting agent, and a reducing agent, wherein the platinum ion solution contains platinum at a concentration of 20 w/v %, the nonionic surfactant is polysorbate 80, the pH adjusting agent is an alkaline metal salt, the reducing agent is a lower alcohol, the volume of the water is from 600 to 660 times that of the platinum ion solution, the volume of the nonionic surfactant is from 0.20 to 0.30 times that of the platinum ion solution, the volume of the pH adjusting agent as a 5 w/v % aqueous solution is from 10 to 30 times that of the platinum ion solution, and the volume of the reducing agent is from 27 to 37 times that of the platinum ion solution,
as well as the platinum colloid produced by the method.