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.

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.

A procedure of minimum environmental impact and maximum lithium recovery for obtaining concentrated brines with minimal impurity content from brines that embed natural salt flats and salt marshes. The procedure may include: building fractional crystallization ponds by solar evaporation; filling the ponds with natural brine; pre-concentrating natural brine to the maximum possible lithium concentration in the liquid phase without precipitating lithium-containing salts; cooling the pre-concentrated brine obtained in ensuring maximum precipitation of salts containing sulfate anion; chemically pre-treating the liquid phase of brine separated from precipitated salts by cooling to minimize sulfate anions in the liquid phase after cooling; pre-concentrating the pre-treated liquid phase to the maximum possible lithium concentration without precipitating lithium-containing salts; chemically treating the liquid phase of brine separated from precipitated salts to minimize the concentration of magnesium, calcium, boron and sulfate in the liquid phase; and concentrating the resulting liquid phase.

A magnesium oxide powder, including a specific magnesium oxide particle, can suppress an increase in viscosity when a resin is filled therewith and can realize high thermal conduction of a resin composition including the resin, and a filler composition, a resin composition, and a heat dissipation part including the magnesium oxide powder. The magnesium oxide powder includes a magnesium oxide particle, wherein an oil absorption of the magnesium oxide particle in the case of linseed oil measured according to JIS K 5101-13-1 is 2.5 mL/10 g or less.

Laminar co-flow methods for the extraction and separation of highly pure Mg(OH).sub.2 and other minerals from complex ionic mixtures by precipitation are disclosed herein. Mineral precipitates prepared according to methods disclosed herein demonstrated exceptional purity, and faster separation compared to conventional bulk methods. LCM mineral extractions were driven by non-equilibrium concentration gradients present at the interface between source and reactant solutions, allowing the methods to operate practically on industrial scale.

Laminar co-flow methods for the extraction and separation of highly pure Mg(OH).sub.2 and other minerals from complex ionic mixtures by precipitation are disclosed herein. Mineral precipitates prepared according to methods disclosed herein demonstrated exceptional purity, and faster separation compared to conventional bulk methods. LCM mineral extractions were driven by non-equilibrium concentration gradients present at the interface between source and reactant solutions, allowing the methods to operate practically on industrial scale.

A novel process for treatment of low quality or brackish water that allows increased recovery of high quality water, recovers commodity minerals and reduces the volume of water and mass of solids that are disposed from the process.

The objective of the present invention is to provide: a spherical magnesium oxide which has high sphericity and excellent moisture resistance, and has excellent fluidity by which a resin composition exhibits excellent fluidity when filled in a resin; and a method for producing the same. The present invention is a spherical magnesium oxide characterized in that: 10-2000 ppm of boron is contained; the total content of silicon and phosphorus is 300-4000 ppm; and the sphericity that can be read from the SEM photograph is 1.00-1.10, when the volume-based cumulative 50% particle diameter (D50) measured by means of a laser diffraction scattering particle size distribution measurement, is in the range of 3-200 μm.

The invention is referred to chemical technology, namely to active high-purity magnesium oxide and its production method.

Active high-purity magnesium oxide, including the surface treated one, has BET specific surface area from 70 to 200 m.sup.2/g, average particle size (d50) determined by laser diffraction method not more than 10 microns, iodine activity in the range from 70 to 200 mg J/g MgO, citric activity not more than 40 s, pore volume in the range from 3.2×10.sup.−2 cm.sup.3/g to 10.2×10.sup.−2 cm.sup.3/g, diameter of 10% of the particles not more than 2 microns, diameter of 90% of the particles not more than 30 microns, mass fraction of residue on the 150 micron sieve not more than 1%, mass fraction of residue on the 45 micron sieve not more than 2%, mass fraction of chlorides not more than 0.1%, mass fraction of calcium not more than 0.1%, mass fraction of substances insoluble in hydrochloric acid not more than 0.05%, mass fraction of iron not more than 0.005%, mass fraction of impurities of each of Ti, Co, Mo, V, Sb, Ba cations not more than 1 ppm, Pb, Cd, As, Hg not more than 0.1 ppm.

Method for the production of active high-purity magnesium oxide including the surface treated one consists of calcination of magnesium hydroxide obtained by interaction of magnesium salt solution with alkaline agent. Magnesium hydroxide crystals are produced by continuous method in divided and isolated between each other zones in the presence of seed crystals of magnesium hydroxide and liquid oil products with mole ratio of ions of alkaline agent and magnesium chloride OH.sup.−/Mg.sup.++ within the range (1.9÷2.1):1, with the temperature in all zones not less than 40° C. and magnesium hydroxide crystals suspension residence time in each isolated zone not less than 20 minutes.

Active high-purity magnesium oxide produced by this method has high activity and high chemical purity that allows to use it as a filler for rubbers, adhesives, plastics, polymers, as stabilizers in production of chloroprene rubbers, refining additives of organic solvents, in production of catalysts, special ceramics, special glass, in pharmaceutical, pharmacopoeial and food industries, in production of magnesia cement and other magnesium-containing materials.

Disclosed herein are system and methods to effectively leach coal ash with hydrochloric acid and separate an insoluble silica product and then selectively precipitate, from the leachate, a number to value-added, strategic, marketable products using a hydroxide reagent. The resulting precipitated products include iron, aluminum, magnesium, calcium, and a mixture of rare earth elements and transition metals. These can be separated as hydroxides or converted to oxides or carbonates. Using hydrochloric acid for leaching and converting the chloride to sodium chloride in the final step results in practically no waste for this process. The silica can be further purified using sodium hydroxide fusion or caustic leach methods and some minor streams from this process are recycled to minimize any waste stream. These systems and methods can be applied to a number of other industrial waste products such as red mud from the aluminum process, slag from steel furnaces, mine tailings, and other metal-bearing waste streams.