A process for leaching a value metal from a base metal sulfide ore, comprising the step of leaching the ore with a lixiviant comprising a chloride, an oxidant and hydrochloric acid is disclosed. The leaching is controlled, by use of low concentrations of hydrochloric acid and a redox potential, to effect formation of hydrogen sulfide from the base metal sulfide ore. The hydrogen sulfide is stripped from the leach solution, thereby reducing the amount of sulfate generated in the leach to very low levels. The leaching may also be conducted to limit the co-dissolution of platinum group metals and gold with the base value metals. The leach forms a value metal-rich leachate and a solids residue. The solids residue may be subsequently leached to recover the platinum group metals and gold. The value metal-rich leachate can be oxidized and neutralized to recover the value base metals. In an embodiment, the chloride is magnesium chloride and lixiviant solution is regenerated.

A process for the recovery of value metals from base metal sulfide ores

An apparatus and a process for producing zinc oxide from a zinc-bearing material are provided. The process comprises the steps of leaching the complex sulfide material with hydrochloric acid, ferric chloride, and oxygen; precipitating iron from the leach solution using lime and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using lime; and regenerating HCI from a calcium chloride leach filtrate solution to regenerate hydrochloric acid and precipitate gypsum. Related processes for recovering copper, silver, lead, and iron from complex sulfide materials and for recovering lead from residue by solubilizing lead chloride and precipitating it with lime are also provided.

Production of zinc oxide from complex sulfide concentrates using chloride processing

A process for recovering a precious metal from a sulfidic material comprises the steps of preparing an acidic aqueous halide solution having an oxidation potential sufficient to oxidise the sulfidic material and render the precious metal soluble in the solution, adding the material to the acidic aqueous halide solution so that the sulfidic material is oxidised and the precious metal is solubilised and separating the precious metal from the oxidised sulfidic material. In addition, a process for removing a contaminant from a contaminated sulfidic material comprises the steps of mixing the material in an aqueous solution wherein a multi-valent species of a relatively high oxidation state oxidises the contaminant to render it soluble in the solution, produces a contaminant refined material, and is reduced to a relatively lower oxidation state; and removing the contaminant from the solution whilst regenerating the multi-valent species to its relatively high oxidation state.

Recovering metals from sulfidic materials

The invention relates to a method for producing copper in a hydrometallurgical process from copper-bearing raw materials, such as sulfidic concentrates. The concentrate is leached in a leaching stage of several steps into a chloride-based solution. The copper-bearing solution obtained from this leaching is subjected to reduction and solution purification, whereafter the copper contained in the solution is precipitated as copper oxidule by means of alkali hydroxide. The alkali chloride solution formed in the production of copper oxidule is fed into chloride alkali electrolysis, where it is regenerated back into alkali hydroxide. The hydrogen generated in the electrolysis is used in the reduction of copper oxidule and in other reduction stages of the process. The formed chlorine is used in the leaching of the raw material. When necessary, the reduced copper that is in a granular or pulverous form is further subjected to melting and casting in order to produce commercial-grade copper.

Method for producing copper in hydrometallurgical process

The present invention is directed to a precious metal recovery process in which basic ferric sulphates and/or jarosites are controlled by a number of mechanisms, including control of the oxidation reaction conditions in the first autoclave compartment, hot curing of the autoclave discharge slurry, and/or contacting of the autoclave feed slurry with the hot cured discharge liquid.

Reduction of lime consumption when treating refractory gold ores or concentrates

A hydrometallurgical process for the separate recovery of non-ferrous, ferrous, and precious metal values and sulfur from metal sulfide ore concentrates by leaching of metal sulfides with a lixiviant containing ferric chloride, cupric chloride and chlorine, precipitating cuprous chloride from the leach solution with butadiene, separating and decomposing the formed addition compound to recover the cuprous chloride, oxidizing and hydrolyzing the cuprous chloride to precipitate cupric oxychloride, converting the cupric oxychloride to cupric oxide, and reducing the cupric oxide with hydrogen for the recovery of copper. The leach residue is treated for the recovery of elemental sulfur and gold. Brine solution resulting from the conversion of cupric oxychloride to cupric oxide is electrolyzed for the production of sodium hydroxide for the cupric oxychloride conversion, hydrogen for the cupric oxide reduction and chlorine, which is partly used in the recovery of gold and partly recycled to the concentrate leach. Silver is recovered as silver iodide from the mother liquor from the cuprous chloride precipitation with butadiene. A portion of the solution from the silver recovery is treated for recovery of Cu, Zn, Co and Ni, and the remaining portion and residual solution from Cu, Zn, Co and Ni recovery are treated with oxygen at elevated temperature and pressure for the regeneration of ferric chloride and precipitation of excess iron as anhydrous ferric oxide.

Hydrometallurgical process for recovering copper and other metal values from metal sulphides

A hydrometallurgical process for treating iron containing metal sulfides for rendering iron and non-ferrous metal values active and amenable for selective extraction and separate recovery. Sulfur values can be controllably produced as elemental sulfur or as sulfuric acid to supply acid requirements of the process, while substantially obviating the discharge of sulfur-containing gases to the atmosphere. Ores and concentrates of the sulfides are thermally activated by sequentially heating and reducing said sulfides in a countercurrent flow of heating and reducing gases respectively in a reactor whereby the reaction products of the reducing gas and sulfides, together with liberated labile sulfur, are controllably combusted with oxygen to satisfy heat requirements of the thermal activation process and to convert sulfur values to SO2 gas. The activated sulfides are subjected to an acid leach in aqueous sulfuric acid for production of ferrous sulfate and evolution of H2 S gas which are separated from the solid sulfide residue containing concentrated non-ferrous metal values. The ferrous sulfate is oxidized and hydrolysed to precipitate the iron, which is removed from the system, and to regenerate sulfuric acid. At least a portion of the SO2 gas from said heating step and at least a portion of the H2 S from the acid leach are converted to sulfuric acid to satisfy the acid requirements of the process, and remaining SO2 is combined and catalytically reacted with remaining H2 S to produce elemental sulfur. The solids residue from the acid leach is subsequently subjected to further treatment for recovery of metal values.

Production of copper and sulfur from copper-iron sulfides

A process for the treatment of complex lead sulfide-containing concentrates additionally containing at least one metal of the group consisting of iron, copper, zinc, silver, arsenic, antimony, bismuth and gold which comprises the steps of selectively leaching a concentrate with iron-containing lixiviant for converting lead sulfide in said concentrate to lead chloride and forming a leach residue and a leach solution, subjecting said lead chloride in the leach residue to a two-stage, countercurrent, hot brine leach to dissolve the lead chloride in a brine-leach solution, subjecting the brine leach solution to crystallization by evaporative cooling for the separate recovery of crystallized lead chloride, residual brine and crystallization condensate, and returning said residual brine to said brine leach, subjecting crystallized lead chloride in admixture with sodium chloride to electrolysis in a fused bath for production of lead and evolution of chlorine, absorbing chlorine in a first portion of said leach solution for the generation of ferric chloride-containing solution; and treating a second portion of said leach solution for the recovery of values. The iron-containing lixiviant comprises an aqueous solution of ferric chloride in a concentration in the range of from 100 to 200 g/l ferric ion or aqueous solutions of ferrous chloride and hydrochloric acid in concentrations in the range of 25 to 160 g/l ferrous chloride and of 60 to 120 g/l hydrochloric acid.

Hydrometallurgical process for treating metal sulfides containing lead sulfide

A process for recovery of zinc values contained in thermally activated iron containing copper and zinc sulfides in which said activated sulfides have been subjected to an acid leach in aqueous sulfuric acid to produce a solution of ferrous sulfate and a solids residue containing copper and zinc values. The solids residue containing copper and zinc values is reacted with an acidic copper sulfate solution to precipitate copper values as a simple copper sulfide with concurrent dissolution of iron and zinc values to form a solution of ferrous sulfate containing said dissolved zinc values and said solution of ferrous sulfate is separated from the simple copper sulfides and reacted with H2 S for precipitation of zinc values therefrom as zinc sulfide. Any nickel and cobalt values present in said activated sulfides is dissolved in said solution of ferrous sulfate and reacted with the H2 S at elevated temperature for selective precipitaton.

Milner Edward F G

Papers

Hydrometallurgical process for recovering copper and other metal values from metal sulphides

Production of copper and sulfur from copper-iron sulfides

Hydrometallurgical process for treating metal sulfides containing lead sulfide

Recovery of copper and zinc as sulfides from copper-iron sulfides