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 MgCl.sub.2.6H.sub.2O 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.

Provided is a friction material composition that can increase the coefficient of friction and the wear resistance, reduce the compressive deformation rate, and improve the yield upon hot forming, even when being free of copper component or having a small content of copper component. The friction material composition contains: titanate compound powder made of non-fibrous titanate compound particles; barium sulfate powder; and a thermosetting resin, wherein the titanate compound powder has an alkali metal ion dissolution rate of 15.0% by mass or less, the barium sulfate powder has a volume-based 50% cumulative particle diameter (D.sub.50) of 0.1 m to 20.0 m, and a content of copper component is 0.5% by mass or less in terms of copper element in a total amount of 100% by mass of the friction material composition.

The present invention relates to methods of refining and recovering barium sulfate from contaminated water sources that include barium cation, such as hydrofracture wastewater. The methods of the present invention result in the formation of a refined and a recovered barium sulfate that has a density of at least 4.10 g/ml, and a content of calcium ion of less than or equal to 250 mg/Kg.

The present invention provides a barium sulfate spherical composite powder that has significantly high strength and excellent texture, and achieves high haze while maintaining high total light transmittance, and a method for producing such a composite powder. The present invention relates to a method for producing a barium sulfate spherical composite powder, which is a method for producing a spherical composite powder of barium sulfate and silica, the method comprising the steps of (1) preparing a slurry containing particulate barium sulfate and a silica sol, (2) spray-drying the slurry, and (3) firing a dry substance obtained in the step (2).

The present invention relates to methods of refining and recovering barium sulfate from contaminated water sources that include barium cation, such as hydrofracture wastewater. The methods of the present invention result in the formation of a refined and a recovered barium sulfate that has a density of at least 4.10 g/ml, and a content of calcium ion of less than or equal to 250 mg/Kg.

A drilling fluid composition that contains micronized barite particles with a particle size in the range of 1 to 5 m, and also a method of fracturing a subterranean formation using the drilling fluid composition. Various embodiments of the micronized barite particles and the method of making thereof, the drilling fluid composition, and the method of fracturing a subterranean formation are also provided.

Disclosed is a method of producing high-purity lithium carbonate and barium sulfate from discarded lithium secondary batteries, including: a first process for producing high-purity lithium phosphate from a discarded battery; and a second process for producing lithium sulfate from the lithium phosphate and producing lithium carbonate and barium sulfate from the lithium sulfate. The second process has steps of (a) producing a liquid mixture of lithium phosphate and sulfuric acid, (b) obtaining lithium sulfate by condensing the liquid mixture, (c) dissolving the lithium sulfate in water or a sodium hydroxide aqueous solution, depositing phosphoric acid as lithium phosphate, and performing solid-liquid separation (d) depositing lithium carbonate and performing solid-liquid separation to obtain lithium carbonate, (e) finely grinding the lithium carbonate and classifying the particles, (f) controlling a particle size and shape by dissolving edges of particles or minute particles, (g) performing solid-liquid separation, and (h) depositing barium sulfate.

A drilling fluid composition that contains micronized barite particles with a particle size in the range of 1 to 5 m, and also a method of fracturing a subterranean formation using the drilling fluid composition. Various embodiments of the micronized barite particles and the method of making thereof, the drilling fluid composition, and the method of fracturing a subterranean formation are also provided.

Disclosed is a method of producing high-purity lithium carbonate from low-purity crude lithium carbonate. The method includes: (a) producing crude lithium carbonate slurry by mixing crude lithium carbonate having a polycrystalline state and a size of 20 to 200 m with water; (b) carbonating and dissolving the crude lithium carbonate slurry; (c) performing primary solid-liquid separation to obtain a filtrate; (d) adding soluble barium salts to the filtrate to deposit barium sulfate; (e) performing secondary solid-liquid separation for the filtrate containing the deposited barium sulfate to obtain a filtrate; (f) mixing lithium carbonate seed crystals with the filtrate obtained from the secondary solid-liquid separation and precipitating lithium carbonate dissolved in the filtrate on surfaces of the lithium carbonate seed crystals to produce high-purity lithium carbonate slurry containing high-purity lithium carbonate by controlling a particle size; and (g) carbonating the high-purity lithium carbonate slurry to produce high-purity lithium carbonate.

A method is provided for recovering barium sulfate from a contaminated water source comprising barium cation. The method involves combining the contaminated water source with a source of sulfate ion, thereby forming a modified contaminated water source. The method includes forming precipitated barium sulfate within the modified contaminated water source; isolating precipitated barium sulfate from the modified contaminated water source, thereby forming isolated precipitated barium sulfate; dewatering the isolated precipitated barium sulfate, thereby forming a low-moisture precipitated barium sulfate; combining the low-moisture precipitated barium sulfate with clean water to form a slurry comprising precipitated barium sulfate; subjecting the slurry to density separation to form a refined barium sulfate; and subjecting the refined barium sulfate to particle size reduction and/or particle size classification to yield a recovered barium sulfate.