Lead is recovered from lead paste of a lead acid battery in a continuous and electrochemical lead recovery process. In especially preferred aspects, lead paste is processed to remove residual sulfates, and the so treated lead paste is subjected to a thermal treatment step that removes residual moisture and reduces lead dioxide to lead oxide. Advantageously, such pretreatment will avoid lead dioxide accumulation and electrolyte dilution.

The present invention discloses a method for preparing iron ore concentrates by recycling copper smelting slag tailings, and belongs to the technical field of metallurgy and tailings recycling. In the present invention, copper slag tailings obtained after copper pyrometallurgy and flotation and water are used as raw materials, and low-concentration sulfur dioxide flue gas is used as a leaching agent for leaching of metals such as iron, zinc, copper, arsenic, and silicon in the slag tailings; the leachate is purified step by step through processes such as replacement by metal iron powder and sulfide precipitation control, to separate zinc, copper, arsenic, etc.; a purified solution is mainly composed of FeSO.sub.4 or can be used for producing a ferric salt flocculant; obtained tailings are used to obtain iron ore concentrates through magnetic separation, and the obtained iron ore concentrates can be used for further producing ultra-pure iron ore concentrates.

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce a low arsenic-bearing gold concentrate. The process may comprise adding oxygen, water, and/or acid to an acidulated arsenic-bearing gold concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step. In one or more examples, the process may further comprise processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds, and applying a first solid/liquid separation and wash step to form a first washed slurry/solid and first acid-containing solutions. The process may further comprise reacting the first washed slurry/solid with sulfur dioxide in a reductive leach step, and applying a second solid/liquid separation and wash step to form a second washed slurry/solid and second acid-containing solutions. The second washed slurry/solid may be a low arsenic-bearing gold concentrate.

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce a low arsenic-bearing gold concentrate. The process may comprise adding oxygen, water, and/or acid to an acidulated arsenic-bearing gold concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step. In one or more examples, the process may further comprise processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds, and applying a first solid/liquid separation and wash step to form a first washed slurry/solid and first acid-containing solutions. The process may further comprise reacting the first washed slurry/solid with sulfur dioxide in a reductive leach step, and applying a second solid/liquid separation and wash step to form a second washed slurry/solid and second acid-containing solutions. The second washed slurry/solid may be a low arsenic-bearing gold concentrate.

Provided is a more efficient dry refining process for improving the recovery rate of phosphorus-free valuable metals from waste lithium ion batteries. The present invention provides a method for recovering valuable metals from waste lithium ion batteries, said method comprises a melting step S4 for melting the waste lithium ion batteries and obtaining a molten substance and a slag separation step S5 for separating slag from the molten substance and recovering an alloy containing valuable metals, wherein in the melting step, flux containing a calcium compound is added to the waste lithium ion batteries such that the mass ratio between silicon dioxide and calcium oxide in the slag becomes 0.50 or less and the mass ratio between calcium oxide and aluminum oxide falls in the range of 0.30 to 2.00.

Process for recovering one or both of copper and silver from a sulphidic feed containing iron, arsenic, copper and silver by pressure oxidizing an aqueous feed slurry of the sulphidic feed in a pressure vessel to form a liquid phase containing free sulphuric acid and aqueous copper sulphate, and to precipitate arsenic as solid iron arsenic compounds. The process includes operating the pressure vessel at a sufficiently low solids content to maintain a free acid level below 30 g/L in the liquid phase, and providing sufficient heat to maintain a temperature in the pressure vessel above 200° C. Copper metal is recovered from the liquid phase and/or silver may be recovered from the solids by cyanide leaching without the need for a jarosite destruction step.

Process for recovering one or both of copper and silver from a sulphidic feed containing iron, arsenic, copper and silver by pressure oxidizing an aqueous feed slurry of the sulphidic feed in a pressure vessel to form a liquid phase containing free sulphuric acid and aqueous copper sulphate, and to precipitate arsenic as solid iron arsenic compounds. The process includes operating the pressure vessel at a sufficiently low solids content to maintain a free acid level below 30 g/L in the liquid phase, and providing sufficient heat to maintain a temperature in the pressure vessel above 200° C. Copper metal is recovered from the liquid phase and/or silver may be recovered from the solids by cyanide leaching without the need for a jarosite destruction step.

Various embodiments utilize selective sulfidation and/or desulfidation for such things as ore and concentrate cracking, metal separation, compound production, and recycling. Selective sulfidation can be used to selectively convert an oxide or other material in a feedstock to a sulfide or other sulfur-containing material, and selective desulfidation can be used to selectively convert a sulfide or other sulfur-containing material in a feedstock to an oxide or other material. In some cases, the material produced by such selective sulfidation/desulfidation of the feedstock can itself be novel and/or commercially valuable, while in other cases, such selective sulfidation/desulfidation can be followed by one or more processes to extract, isolate, or concentrate the converted material.

Various embodiments utilize selective sulfidation and/or desulfidation for such things as ore and concentrate cracking, metal separation, compound production, and recycling. Selective sulfidation can be used to selectively convert an oxide or other material in a feedstock to a sulfide or other sulfur-containing material, and selective desulfidation can be used to selectively convert a sulfide or other sulfur-containing material in a feedstock to an oxide or other material. In some cases, the material produced by such selective sulfidation/desulfidation of the feedstock can itself be novel and/or commercially valuable, while in other cases, such selective sulfidation/desulfidation can be followed by one or more processes to extract, isolate, or concentrate the converted material.

A process is disclosed for the recovery of a metal from a pyrite-bearing material. The process comprises thermally decomposing the pyrite-bearing material so as to produce a material comprising pyrrhotite (FeS). The process also comprises leaching the material comprising pyrrhotite with an acid such that the iron in the pyrrhotite is oxidised to a +3 oxidation state, elemental sulphur is produced and the metal is released from the pyrite-bearing material.