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 ammonium complex system-based method for separating and purifying lead, zinc, cadmium, and copper, comprising the following steps: a zinc-containing raw material is leached using a leach solution to produce a leached solution; a filtrate and a filter residue are produced by filtration; the filtrate is mixed with metal lead to displace copper, undergoes a solid-liquid separation to produce a first separated liquid, is mixed with metal cadmium to displace lead, undergoes a solid-liquid separation to produce a second separated liquid, is mixed with metal zinc to displace cadmium, and undergoes a solid-liquid separation to produce a third separated liquid; and, the third separated liquid is electrolyzed to produce metal zinc, and an electrolytic solution is returned to the leaching step.

The invention relates to the field of efficient separation and recovery of bromine by full wet method, especially to a two-step separating method of bromide and recovery of lead and zinc from printed circuit board Incineration ash. It mainly includes first sodium hydroxide alkaline leaching, secondary sodium peroxide alkaline leaching, pH adjustment, separate lead and zinc, bromide evaporation and crystallization to recover crude bromide and other steps. Compared with traditional comprehensive recovery process of ash, the invention uses sodium hydroxide to dissolve bromide, lead and zinc, and uses the strong oxidation of sodium peroxide in alkaline environment, copper bromide and other bromine are oxidized and leached; through two-step method, the efficient leaching of bromine, lead and zinc is realized, silver and other precious metals are enriched at the same time. It is beneficial to subsequent recovery of precious metals and has the characteristics of short tail liquid discharge.

Provided is a method for producing calcium zincate. The method comprises: an extraction step: mixing a ground zinc-containing raw material with an extracting agent, followed by filtration to obtain an extract, wherein the extracting agent is a mixed aqueous solution of ammonia and {NH.sub.4HCO.sub.3 and/or (NH.sub.4).sub.2CO.sub.3; optionally, purifying the extract; a decarburization step: adding calcium oxide and/or calcium hydroxide to the extract, stirring, and filtering to obtain a first solid and a first filtrate; a calcium zincate synthesis step: adding calcium hydroxide and/or calcium oxide to the first filtrate, stirring to react, and filtering to obtain a second solid and a second filtrate; optionally, rinsing the second solid with water; a drying step: drying the second solid to obtain the final calcium zincate product.

Provided is a method for producing calcium zincate. The method comprises: an extraction step: mixing a ground zinc-containing raw material with an extracting agent, followed by filtration to obtain an extract, wherein the extracting agent is a mixed aqueous solution of ammonia and {NH.sub.4HCO.sub.3 and/or (NH.sub.4).sub.2CO.sub.3; optionally, purifying the extract; a decarburization step: adding calcium oxide and/or calcium hydroxide to the extract, stirring, and filtering to obtain a first solid and a first filtrate; a calcium zincate synthesis step: adding calcium hydroxide and/or calcium oxide to the first filtrate, stirring to react, and filtering to obtain a second solid and a second filtrate; optionally, rinsing the second solid with water; a drying step: drying the second solid to obtain the final calcium zincate product.

The invention relates to the field of efficient separation and recovery of bromine by full wet method, especially to a two-step separating method of bromide and recovery of lead and zinc from printed circuit board Incineration ash. It mainly includes first sodium hydroxide alkaline leaching, secondary sodium peroxide alkaline leaching, pH adjustment, separate lead and zinc, bromide evaporation and crystallization to recover crude bromide and other steps. Compared with traditional comprehensive recovery process of ash, the invention uses sodium hydroxide to dissolve bromide, lead and zinc, and uses the strong oxidation of sodium peroxide in alkaline environment, copper bromide and other bromine are oxidized and leached; through two-step method, the efficient leaching of bromine, lead and zinc is realized, silver and other precious metals are enriched at the same time. It is beneficial to subsequent recovery of precious metals and has the characteristics of short tail liquid discharge.

Described is a method of recovering a metal from a substrate having a metal sulphide, metal oxide, or combination thereof, by contacting the substrate with an aqueous oxidant to oxidize the metal sulphide to elemental sulphur and oxidized metal or convert the complex metal oxide to a metal salt, contacting the oxidized metal or simple metal oxide with ammonium hydroxide to form soluble a ammine complex of the metal to obtain a leachate and residual solids; separating the leachate from the residual solids; and recovering the metal.

A process for recovering non-ferrous metals from a solid matrix may include: (a) leaching the solid matrix with an aqueous-based solution containing chloride ions, ammonium ions, and Cu.sup.2+ ions, having a pH of 6.5-8.5, in a presence of oxygen, at a temperature of 100 C.-160 C. and a pressure of 150 kPa-800 kPa, so as to obtain an extraction solution comprising leached metals and solid leaching residue; (b) separating the solid leaching residue from the extraction solution; and/or (c) subjecting the extraction solution to at least one cementation so as to recover the leached metals in elemental state. The pH may be greater than or equal to 6.5 and less than or equal to 8.5. Temperature may be greater than or equal to 100 C. and less than or equal to 160 C. Pressure may be greater than or equal to 150 kPa and less than or equal to 800 kPa.

Described is a method of recovering a metal from a substrate having a metal sulphide, metal oxide, or combination thereof, by contacting the substrate with an aqueous oxidant to oxidize the metal sulphide to elemental sulphur and oxidized metal or convert the complex metal oxide to a metal salt, contacting the oxidized metal or simple metal oxide with ammonium hydroxide to form soluble a ammine complex of the metal to obtain a leachate and residual solids; separating the leachate from the residual solids; and recovering the metal.

A process for recovering zinc from a zinc containing material, the process including the steps of: leaching the zinc containing material with an alkaline lixiviant comprising an aqueous mixture of NH.sub.3 and NH.sub.4Cl, or ionic equivalent, having a NH.sub.4Cl concentration of between about 10 g/L and about 150 g/L H.sub.2O and a NH.sub.3 concentration of between 20 g/l H.sub.2O and 250 g/L H.sub.2O, to produce a zinc containing leachate; stripping ammonia from the leachate to produce a stripped liquor which includes a zinc containing precipitate, the stripped liquor having a NH.sub.3 concentration of between 7 and 30 g/L H.sub.2O; and recovering the zinc from the stripped liquor.