Abstract: A method for selectively processing a polymetallic oxide solution containing a plurality of base metals comprising at least one of: Cu, Co, Ni, Zn associated with iron, comprising acid leaching the solution; recovering a filtered leachate; oxidizing the leachate; and adjusting the pH of the leachate in presence of a complexing agent; wherein the acidic solution is one of: i) a hydrochloric acid solution and ii) a sulfuric acid solution at a pH lower than about 1.5, and the complexing agent is one of: i) ammonium chloride and ii) ammonium sulfate, the step of adjusting the pH comprising raising the pH to a range between about 2.5 and about 3.5.

Abstract: A method for recovering precious metal from an acidic pregnant solution resulting from halogen or hypohalite leaching of an ore, comprising lowering the ORP of the pregnant leachate with a reducing agent in the presence of slurried non-carboneous particles. The precious metal deposits on the surfaces of the particles and a barren solution comprising substantially all the halogen values of the pregnant solution in the form of sodium chloride, sodium bromide or hypohalites is recovered.

Abstract: A method for selectively processing a polymetallic oxide solution containing a plurality of base metals comprising at least one of: Cu, Co, Ni, Zn associated with iron, comprising acid leaching the solution; recovering a filtered leachate; oxidizing the leachate; and adjusting the pH of the leachate in presence of a complexing agent; wherein the acidic solution is one of: i) a hydrochloric acid solution and ii) a sulfuric acid solution at a pH lower than about 1.5, and the complexing agent is one of: i) ammonium chloride and ii) ammonium sulfate, the step of adjusting the pH comprising raising the pH to a range between about 2.5 and about 3.5.

Abstract: A method for sequestrating arsenic oxides, comprising forming an insoluble and stable glass incorporating a fully oxidized form of arsenic generated by oxidation of an initial lower oxide of arsenic and stabilization by calcium salt formation. The glass composition for sequestration of arsenic comprises from 50 to 75% silica; from 0.5 to 3% Al2O3; from 1 to 15% MnO; from 5 to 15% CaO; from 1 to 20% As2O5 and from 8 to 14% Na2O, less than four percent of iron oxides, magnesium oxide and other oxides.

Abstract: A method and a system for the production of potassium sulfate. The method comprises reacting a chloride of potassium with a magnesium sulfate in an aqueous alcoholic solution, with recycling of magnesium sulfate and production of hydrochloric acid, where the recycling of magnesium is done by a reaction of sulfuric acid on resulting magnesium chloride with corresponding production of magnesium sulfate and hydrochloric acid.

Abstract: The invention relates to a method for the extraction of precious metals, using halogens. It has been found that introducing halogens in the reactor in the form of hypohalites rather than free halogens simplified greatly the recycling of halogens by electrolysis. It increases the rate of addition of the halogens and significantly reduces secondary reactions with base metals such as iron. Operating under acidic conditions, the gold recovery has been found as high with hypochlorite as with elemental chlorine, with an active chlorine to ore ratio reduced by a factor of two to five.

Abstract: A method and a system for the production of potassium sulfate. The method comprises reacting a source of water soluble potassium with a magnesium sulfate-containing substance in presence of an aqueous alcoholic solution.

Abstract: A process for producing potassium magnesium sulfate, comprising reacting sulfuric acid with potassium chloride and magnesium chloride at a temperature in a range comprised between about 100 and about 160° C., thereby producing potassium magnesium sulfate and hydrochloric acid, the sulfuric acid being reacted with potassium chloride and magnesium chloride simultaneously or sequentially.

Abstract: A method for treating a polymetallic sulfide ore containing gold and/or silver, and further containing base metals selected from the group consisting of iron, aluminum, chromium, titanium, copper, zinc, lead, nickel, cobalt, mercury, tin, and mixtures thereof, is disclosed. The method comprises the steps of grinding the polymetallic sulfide ore to produce granules, oxidizing the granules to produce oxidized granules, and chloride leaching the granules using a brine solution including dissolved halogens, as well as chloride and bromide salts.

Abstract: A method for treating a polymetallic sulfide ore containing gold and/or silver, and further containing base metals selected from the group consisting of iron, aluminum, chromium, titanium, copper, zinc, lead, nickel, cobalt, mercury, tin, and mixtures thereof, is disclosed. The method comprises the steps of grinding the polymetallic sulfide ore to produce granules, oxidizing the granules to produce oxidized granules, and chloride leaching the granules using a brine solution including dissolved halogens, as well as chloride and bromide salts.

Abstract: A method for treating a polymetallic sulfide ore containing gold and/or silver, and further containing base metals selected from the group consisting of iron, aluminum, chromium, titanium, copper, zinc, lead, nickel, cobalt, mercury, tin, and mixtures thereof, is disclosed. The method comprises the steps of grinding the polymetallic sulfide ore to produce granules, oxidizing the granules to produce oxidized granules, and chloride leaching the granules using a brine solution including dissolved halogens, as well as chloride and bromide salts.