Abstract: It is disclosed the use of amorphous silica reagent produced from serpentine as pozzolane additive material, and more particularly a concrete mixture, such as high performance and ultra-high performance concrete, comprising a hydraulic binder; sand; aggregates, chemical admixture, mineral admixture as silica fume and an amorphous silica reagent (AmSR), wherein the AmSR is admixed for example with General Use Portland Cement and provides synergistic effect when combined with silica fume.

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 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: 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 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 resudial 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: A device for purifying liquid wastewater, includes: a container suitable for retaining a granulate consisting of solid particles, and for enabling the contact between the solid particles of the granulate and the liquid wastewater flowing in the container between: an inlet for the liquid wastewater to flow into the container, and an outlet for substantially decontaminated water to flow out of the container; a community of microorganisms extending so as to be in contact with the solid particles of the granulate; at least one live benthic invertebrate whose mean size is greater than 250 ?m and which is distributed in the granulate; and at least one live benthic invertebrate whose mean size is from 50 ?m to 250 ?m and which is distributed in the granulate, characterized in that the community of macrobenthic organism and meiobenthic organism species includes a proportion of 60% to 80% of invertebrate detrivorous organisms.

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: There are provided methods for preparing hematite. For example, the method can comprise reacting a basic aqueous composition comprising the iron and the aluminum with hematite under conditions suitable for at least partially converting the iron into hematite under the form of a precipitate, thereby obtaining a liquid phase and a solid phase; and separating the liquid phase from the solid phase.

Abstract: There are provided methods for separating iron ions from aluminum ions. For example, the methods can comprise providing a basic aqueous composition comprising said iron ions and said aluminum ions and having a pH of about 10.5 to about 13 and a temperature of about 50 ° C. to about 150 ° C.; reacting said basic aqueous composition with hematite so as to promote, catalyze and/or enhance formation of hematite and to obtain a liquid phase comprising said aluminum ions and a solid phase comprising said so-formed hematite generated with said iron ions; and separating said liquid phase from said solid phase.

Abstract: A device for purifying liquid wastewater, includes: a container suitable for retaining a granulate consisting of solid particles, and for enabling the contact between the solid particles of the granulate and the liquid wastewater flowing in the container between: an inlet for the liquid wastewater to flow into the container, and an outlet for substantially decontaminated water to flow out of the container; a community of microorganisms extending so as to be in contact with the solid particles of the granulate; at least one live benthic invertebrate whose mean size is greater than 250 ?m and which is distributed in the granulate; and at least one live benthic invertebrate whose mean size is from 50 ?m to 250 ?m and which is distributed in the granulate, characterized in that the community of macrobenthic organism and meiobenthic organism species includes a proportion of 60% to 80% of invertebrate detrivorous organisms.

Abstract: There are provided methods for preparing hematite. For example, the method can comprise reacting a basic aqueous composition comprising the iron and the aluminum with hematite under conditions suitable for at least partially converting the iron into hematite under the form of a precipitate, thereby obtaining a liquid phase and a solid phase; and separating the liquid phase from the solid phase.

Abstract: There are provided methods for separating iron ions from aluminum ions contained in an acidic composition. The methods comprise reacting the acidic composition with a basic aqueous composition having a pH of at least 10.5 so as to obtain a precipitation composition, maintaining the precipitation composition at a pH above 10.5 so as to cause precipitation of the iron ions, at least substantially preventing precipitation of the aluminum ions, and to obtain a mixture comprising a liquid portion and a solid portion; and separating the liquid portion from the solid portion. There are also provided methods for treating an acidic composition comprising iron ions and aluminum ions. Such methods can be useful for preparing products such as alumina, aluminum, hematite etc.