A filler composition comprising fibrous basic magnesium sulfate particles and non-fibrous inorganic micro-particles having an average particle diameter in the range of 0.001 to 0.5 m in a ratio by weight in the range of 100:0.001 to 100:50, is used for providing a molded resin product which shows impact resistance and rigidity balanced at a high level.

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.

A process for converting gypsum into precipitated calcium carbonate including reacting a mixture comprising gypsum and a seed, a mineral acid, or both with at least one carbonate source, whereby precipitated calcium carbonate is produced in the form of calcite and/or aragonite directly without conversion from a vaterite polymorph. Also, a process for converting gypsum into precipitated calcium carbonate including providing a mixture comprising i) gypsum ii) a seed, a mineral acid, or both iii) at least one additive selected from the group consisting of ammonium sulfate, an organic acid, or an iron material, and reacting the mixture with at least one carbonate source to produce precipitated calcium carbonate in the form of vaterite. The precipitated calcium carbonates having desired and unique compositions, polymorph and crystal size characteristics formed by these processes.

A process for converting gypsum into precipitated calcium carbonate including reacting a mixture comprising gypsum and a seed, a mineral acid, or both with at least one carbonate source, whereby precipitated calcium carbonate is produced in the form of calcite and/or aragonite directly without conversion from a vaterite polymorph. Also, a process for converting gypsum into precipitated calcium carbonate including providing a mixture comprising i) gypsum ii) a seed, a mineral acid, or both iii) at least one additive selected from the group consisting of ammonium sulfate, an organic acid, or an iron material, and reacting the mixture with at least one carbonate source to produce precipitated calcium carbonate in the form of vaterite. The precipitated calcium carbonates having desired and unique composition, polymorph and crystal size characteristics formed by these processes.

A magnesium sulfate-based desiccant comprising powder composed of coated particles that contain a particle of magnesium sulfate represented by the chemical formula MgSO.sub.4.nH.sub.2O (0n3) and a coating layer on the surface of the particle, wherein: (1) the coating layer contains a coating material that is at least one of carboxylic acids and salts thereof; (2) the powder has an average particle diameter of 5 m or less; and (3) a contact angle of water relative to the face formed with the powder is 20 degrees or more, and to a method for producing the same.

A magnesium sulfate-based desiccant comprising powder composed of coated particles that contain a particle of magnesium sulfate represented by the chemical formula MgSO.sub.4.nH.sub.2O (0n3) and a coating layer on the surface of the particle, wherein: (1) the coating layer contains a coating material that is at least one of carboxylic acids and salts thereof; (2) the powder has an average particle diameter of 5 m or less; and (3) a contact angle of water relative to the face formed with the powder is 20 degrees or more, and to a method for producing the same.

Fibrous basic magnesium sulfate having excellent acid resistance. A fibrous powder comprising the fibrous basic magnesium sulfate, and an anionic surfactant (A) and a cationic surfactant (B), both coating the surface of the fibrous basic magnesium sulfate.

The present invention relates to a method for recovering magnesium from sediment generated in an electrolytic chlorine generation system using seawater or brackish water, the method comprising the steps of: eluting magnesium by using sulfuric acid in magnesium hydroxide, which is sediment generated in an electrolytic chlorine generation system using seawater and brackish water; precipitating magnesium sulfate by adding an organic solvent to a magnesium-eluted solution; and after the precipitation of the magnesium sulfate, separating the organic solvent and sulfuric acid by using a vacuum evaporation method, and reusing the organic solvent.

The present invention relates to a method for recovering magnesium from sediment generated in an electrolytic chlorine generation system using seawater or brackish water, the method comprising the steps of: eluting magnesium by using sulfuric acid in magnesium hydroxide, which is sediment generated in an electrolytic chlorine generation system using seawater and brackish water; precipitating magnesium sulfate by adding an organic solvent to a magnesium-eluted solution; and after the precipitation of the magnesium sulfate, separating the organic solvent and sulfuric acid by using a vacuum evaporation method, and reusing the organic solvent.

Processes for regenerating alkali process streams are disclosed herein, including streams containing sodium hydroxide, magnesium hydroxide, and combinations thereof. Systems for regenerating alkali process streams are disclosed herein, including streams containing sodium hydroxide, magnesium hydroxide, and combinations thereof.