A method is disclosed for extracting metals from concentrated sulphurated minerals containing metals by direct reduction with regeneration and recycling of the reducing agent, iron, and of the flux, sodium carbonate. It is a combination of pyrometallurgical and hydrometallurgical processes which differ from the conventional processes. They do not require previous toasting of the concentrated sulphurated minerals and are technically and economically more advantageous than the presently used processes, since they directly reduce to zero the positive oxidation state of the metal, using a single reactor for extracting the metal, regenerating and recycling the metallurgical feed materials in complementary processes, the kinetics of the chemical reactions being characterised by high speed, without generating any slags or pollutant gases. The metals can be extracted at a reduced cost and in an environmentally sustainable manner

A method is disclosed for extracting metals from concentrated sulphurated minerals containing metals by direct reduction with regeneration and recycling of the reducing agent, iron, and of the flux, sodium carbonate. It is a combination of pyrometallurgical and hydrometallurgical processes which differ from the conventional processes. They do not require previous toasting of the concentrated sulphurated minerals and are technically and economically more advantageous than the presently used processes, since they directly reduce to zero the positive oxidation state of the metal, using a single reactor for extracting the metal, regenerating and recycling the metallurgical feed materials in complementary processes, the kinetics of the chemical reactions being characterised by high speed, without generating any slags or pollutant gases. The metals can be extracted at a reduced cost and in an environmentally sustainable manner

There is provided a method for the removal of arsenic from an arsenical bearing sulfides ore, comprising a thermal treatment of arsenical sulfide in the presence of sulfur dioxide, yielding a calcine and a sublimate, the sublimate containing arsenious oxide. The method allows recovering metallic value from an arsenic-bearing metallic sulfides ore, by recovery of the calcine comprising the metallic value of the ore.

A method for preparing high-purity metallic arsenic from arsenic-containing solid waste through a short flow process is provided. The method includes: performing oxidative alkaline leaching on nonferrous metallurgy arsenic-containing solid waste to obtain an arsenic-containing alkaline leaching solution; sequentially adding a mixed ammonium magnesium reagent consisting of a carboxyl and/or hydroxy-containing water-soluble macromolecular organic matter, a magnesium compound and an ammonium compound, and a hydrophobic macromolecular organic matter having a periodic geometric structure into the arsenic-containing alkaline leaching solution, and taking a reaction under stirring to obtain complex arsenate crystals cladded with an organic matter; and roasting the complex arsenate crystals cladded with the organic matter, then mixing the roasted complex arsenate crystals cladded with the organic matter with carbon powder, performing reduction roasting, and recycling metallic arsenic from smoke through condensation.

A method for preparing high-purity metallic arsenic from arsenic-containing solid waste through a short flow process is provided. The method includes: performing oxidative alkaline leaching on nonferrous metallurgy arsenic-containing solid waste to obtain an arsenic-containing alkaline leaching solution; sequentially adding a mixed ammonium magnesium reagent consisting of a carboxyl and/or hydroxy-containing water-soluble macromolecular organic matter, a magnesium compound and an ammonium compound, and a hydrophobic macromolecular organic matter having a periodic geometric structure into the arsenic-containing alkaline leaching solution, and taking a reaction under stirring to obtain complex arsenate crystals cladded with an organic matter; and roasting the complex arsenate crystals cladded with the organic matter, then mixing the roasted complex arsenate crystals cladded with the organic matter with carbon powder, performing reduction roasting, and recycling metallic arsenic from smoke through condensation.

The disclosure relates to the oxidation and immobilization of trivalent arsenic from arsenic-containing solutions. The process includes oxidation of trivalent arsenic (As.sup.3+) species to the pentavalent state (As.sup.5+). A carbon additive (e.g., activated carbon) and oxygen are used to promote the arsenic oxidation processes. After oxidation of arsenic to the pentavalent state, the arsenic can be removed by precipitation to ferric arsenate or calcium arsenate or other arsenic containing compounds known in the art. The oxidation of arsenic can also occur simultaneously with the production and precipitation of ferric arsenate (e.g., scorodite). Ferrous iron can be oxidized to ferric iron in the presence of activated carbon and oxygen.

The disclosure relates to the oxidation and immobilization of trivalent arsenic from arsenic-containing solutions. The process includes oxidation of trivalent arsenic (As.sup.3+) species to the pentavalent state (As.sup.5+). A carbon additive (e.g., activated carbon) and oxygen are used to promote the arsenic oxidation processes. After oxidation of arsenic to the pentavalent state, the arsenic can be removed by precipitation to ferric arsenate or calcium arsenate or other arsenic containing compounds known in the art. The oxidation of arsenic can also occur simultaneously with the production and precipitation of ferric arsenate (e.g., scorodite). Ferrous iron can be oxidized to ferric iron in the presence of activated carbon and oxygen.

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce the low arsenic-bearing gold concentrate. The process comprises: (i) optionally regrinding the input arsenic-bearing gold concentrate; (ii) optionally treating the reground gold concentrate with sulfuric or other aqueous acid in an acidulation step; (iii) adding oxygen, water and/or acid to the acidulated concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step; (iv) processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds; (v) applying a first solid/liquid separation and wash step, comprising at least one of a thickening step, a counter current decantation (CCD) wash step, and a filter and wash step, to form a first washed slurry/solid and first acid-containing solutions; (vi) reacting the first washed slurry/solid with sulfur dioxide (and optionally sulfuric acid and/or water) in a reductive leach step; (vii) applying a second solid/liquid separation and wash step, comprising at least one of a thickening step, a CCD wash step and a filter and wash step, to form a second washed slurry/solid and second acid-containing solutions, wherein the first and second acid-containing solutions can be recycled to the acidulation and/or pressure oxidation steps; and (viii) applying an optional surface cleaning step, to produce low arsenic bearing gold concentrate.

A process for reducing arsenic content from arsenic-bearing gold concentrate or other arsenic-bearing gold materials to produce the low arsenic-bearing gold concentrate. The process comprises: (i) optionally regrinding the input arsenic-bearing gold concentrate; (ii) optionally treating the reground gold concentrate with sulfuric or other aqueous acid in an acidulation step; (iii) adding oxygen, water and/or acid to the acidulated concentrate slurry and reacting them together in an autoclave at an elevated pressure and temperature in a pressure oxidation step; (iv) processing the oxidized concentrate slurry in an arsenic re-dissolution step to dissolve unstable solid arsenic compounds; (v) applying a first solid/liquid separation and wash step, comprising at least one of a thickening step, a counter current decantation (CCD) wash step, and a filter and wash step, to form a first washed slurry/solid and first acid-containing solutions; (vi) reacting the first washed slurry/solid with sulfur dioxide (and optionally sulfuric acid and/or water) in a reductive leach step; (vii) applying a second solid/liquid separation and wash step, comprising at least one of a thickening step, a CCD wash step and a filter and wash step, to form a second washed slurry/solid and second acid-containing solutions, wherein the first and second acid-containing solutions can be recycled to the acidulation and/or pressure oxidation steps; and (viii) applying an optional surface cleaning step, to produce low arsenic bearing gold concentrate.

Process for the removal of arsenic from materials with a high arsenic content or materials with a high content in arsenic and selenium that comprises: Adding the material to a pressurized reactor; Adding an alkaline lixiviating solution of a strong base dissolved in water to the reactor; Adding an oxidizing gas to the reactor; Mixing the above components in the reactor to obtain a homogenous pulp and subjecting it to a lixiviation under pressure that is selective for arsenic with respect to the other elements of interest present in the treated material; Subjecting the pulp obtained from the lixiviation step to a first solid-liquid separation step, thereby obtaining a liquor with dissolved arsenic and a solid with low arsenic content; Subjecting the liquor with dissolved arsenic to a precipitation of the arsenic with a precipitating agent, selecting compounds that supply the following cations: Ce.sup.3+, Fe.sup.3+, Mg.sup.2+, and a combination of Fe.sup.3+ and Ca.sup.2+; And, subjecting the product of the arsenic precipitation step to a second solid-liquid separation step, thereby obtaining a solid arsenic-containing product and an alkaline liquor free of arsenic.

Optionally the process also comprises: Subjecting the alkaline liquor free of arsenic to a sodium sulfate (Na.sub.2SO.sub.4) crystallization step, thereby obtaining a pulp composed of Na.sub.2SO.sub.4 crystals and an alkaline liquor free of Na.sub.2SO.sub.4; Subjecting the product of the Na.sub.2SO.sub.4 precipitation step to a third solid-liquid separation step, thereby obtaining a solid comprising Na.sub.2SO.sub.4 crystals and an alkaline liquor.