Abstract: It is provided a process of producing amorphous silica from a raw material, such as serpentine, containing silica comprising the steps of mixing the raw material with a hydrochloric acid solution; leaching the raw material obtaining a slurry comprising a liquid fraction and a solid fraction containing silica and minerals; separating the liquid fraction and the solid fraction; removing the minerals from the solid fraction by magnetic separation producing a purified solid silica; drying the purified solid silica; and heating the purified solid silica to remove hydroxyl groups from the silica surface and reducing specific surface area of the resulting amorphous silica.

Abstract: The present description relates to a process for producing magnesium metal from dihydrate magnesium chloride comprising the steps of dehydrating MgCI2.2H2O with anhydrous hydrochloric acid (HCI) to obtain anhydrous magnesium chloride in an inert environment, releasing the mixture of hydrous HCI and protection gas; and electrolyzing the anhydrous magnesium chloride in an electrolytic cell fed with hydrogen gas under free oxygen atmosphere content, wherein magnesium metal and anhydrous hydrogen chloride are produced, wherein a part of the hydrous HCI is passed through a scrubbing unit to obtain a hydrochloric acid solution, the other part of the hydrochloric chloride gas is dehydrated by contact with a desiccant agent in a drying unit to produce anhydrous HCI, and wherein the anhydrous HCI produced by at least one of the electrolytic cell and the drying unit is reused to dehydrate the of MgCI2.2H2O.

Abstract: The present description relates to a process for producing magnesium metal from magnesium-bearing ores using serpentine. The process described herein consists generally in a mineral preparation and classification followed by leaching with dilute hydrochloric acid. The slurry is filtered and the non-leached portion, containing amorphous silica is recovered. The residual solution is neutralized and purified by chemical precipitation with non activated and activated serpentine. The nickel is also recovered by precipitation at higher pH. A final neutralisation and purification step of magnesium chloride solution by precipitation allows eliminating any traces of residual impurities. The purified magnesium chloride solution is evaporated until saturation and the MgCl2.6H2O is recovered by crystallization in an acid media. The salt is dehydrated and subsequent electrolysis of anhydrous magnesium chloride produces pure magnesium metal and hydrochloric acid.

Abstract: The present description relates to an anode arrangement for use in an electrolysis production of metals comprising an anode having a hollow body comprising a cavity, the body having at least one gas outlet connected in flow communication with the cavity. A gas inlet is connected in fluid flow communication with the cavity of the anode, the gas inlet being connectable to a source of hydrogen gas for feeding hydrogen gas into the cavity of the anode. The anode arrangement also comprises an electrical connector and a hydrogen chloride (HCl) recuperator surrounding at least a portion of the anode for recovering HCl gas released through the at least one gas outlet at an outer surface of the anode during electrolysis.

Abstract: The present description relates to a process for extracting magnesium compounds from magnesium-bearing ores comprising leaching serpentine tailing with dilute HCl to dissolve the magnesium and other elements like iron and nickel. The residual silica is removed and the rich solution is further neutralized to eliminate impurities and recover nickel. Magnesium chloride is transformed in magnesium sulfate and hydrochloric acid by reaction with sulfuric acid. The magnesium sulfate can be further decomposed in magnesium oxyde and sulphur dioxyde by calcination. The sulphur gas can further be converted into sulfuric acid.

Abstract: The present description relates to a process for producing magnesium metal from dihydrate magnesium chloride comprising the steps of dehydrating MgCI2.2H2O with anhydrous hydrochloric acid (HCI) to obtain anhydrous magnesium chloride in an inert environment, releasing the mixture of hydrous HCI and protection gas; and electrolyzing the anhydrous magnesium chloride in an electrolytic cell fed with hydrogen gas under free oxygen atmosphere content, wherein magnesium metal and anhydrous hydrogen chloride are produced, wherein a part of the hydrous HCI is passed through a scrubbing unit to obtain a hydrochloric acid solution, the other part of the hydrochloric chloride gas is dehydrated by contact with a desiccant agent in a drying unit to produce anhydrous HCI, and wherein the anhydrous HCI produced by at least one of the electrolytic cell and the drying unit is reused to dehydrate the of MgCI2.2H2O.