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.

Porous amorphous silica can be obtained from siliceous plant matter containing non-siliceous inorganic substances. The siliceous plant matter is soaked in an aqueous solution which includes a chelating agent. The chelating agent is present in an amount which helps to extract at least some of the non-siliceous inorganic matter. The aqueous solution is then separated from the siliceous plant matter. Beneficial properties are imparted to the siliceous plant matter by controlling the amount of at least one preselected non-siliceous inorganic substance in the siliceous plant matter. At the end of the process, the siliceous plant matter is heat treated in the presence of oxygen at a temperature to produce the resulting amorphous silica having the beneficial properties.

The present disclosure provides for silicon nanoparticles, safety devices, solid propellants, and the like.

A method for forming hollow silica spheres by dissolving a hydrolyzable aryl silane in an aqueous solution of water and an acid to form a hydrolyzed silane solution, mixing the hydrolyzed silane solution with a hydroxide base to form a precipitate, and calcining the precipitate in a multi-stage calcination procedure that includes (a) heating to a first temperature of 180 to 240 C. with a first ramp rate of 3 to 10 C./min and holding the first temperature for 2 minutes to 2 hours, then (b) heating to a second temperature of 600 to 740 C. at a second ramp rate of 0.1 to 4 C./min, and holding the second temperature for 2 to 24 hours.

A method is presented for producing hollow microspheres of metal oxides (HMOMS) and/or hollow metal silicates microspheres (HMSMS) in a transforming solution. The transforming solution contains an atom M, or an M-ion, or a radical containing M. M in the transforming solution has the thermodynamic ability to replace silicon atoms in hollow silica microspheres (HSMS) and/or hollow glass microspheres (HGMS). The maximum temperature for transformation is set by the chemical physical properties of the transforming solution, and the viscosity of the silica in the walls of the HSMS and/or the glass in the walls of the HGMS. Viscosity, of enough magnitude, helps retain the desired shape of the hollow sphere as it is transformed to HMOMS and/or HMSMS. Non-spherical shapes can be produced by increasing the transformation temperature whereby the viscosity of the walls of the HSMS and/or the HGMS is reduced. Transformation can take place at a single temperature or at several temperatures, each temperature for a separate hold time. Methods are presented for: 1. production of micro composite castings and continuous production of sheets of micro composites, both consisting of hollow spheres in a matrix, 2. harvesting of HMOMS and HMSMS, and 3. specialty castings for anisotropic properties using 3-dimensional printing.

A method for forming hollow silica spheres by dissolving a hydrolyzable aryl silane in an aqueous solution of water and an acid to form a hydrolyzed silane solution, mixing the hydrolyzed silane solution with a hydroxide base to form a precipitate, and calcining the precipitate in a multi-stage calcination procedure that includes (a) heating to a first temperature of 180 to 240? C. with a first ramp rate of 3 to 10? C./min and holding the first temperature for 2 minutes to 2 hours, then (b) heating to a second temperature of 600 to 740? C. at a second ramp rate of 0.1 to 4? C./min, and holding the second temperature for 2 to 24 hours.

Provided is a process for producing satisfactory particles held in porous silica. The process comprises (a) the step of preparing porous silica, (b) the step of bringing the porous silica into contact with a liquid which contains either a metal or a compound that has the metal as a component element and infiltrating the liquid into the pores of the porous silica, and (c) the step of subjecting, after the step (b), the impregnated porous silica to a heat treatment to thereby form fine particles comprising the metal or the metal compound in the pores of the porous silica. When porous silica is synthesized by hydrolyzing an alkoxysilane in a solvent-free system, it is possible to synthesize porous silica having a fine pore diameter. Use of this porous silica as a template facilitates formation of particles (e.g., W, Cu, Cr, Mn, Fe, Co, or Ni or an oxide of any of these metals) that show peculiar properties not observed in the bulk material.

The present disclosure provides for silicon nanoparticles, safety devices, solid propellants, and the like.

Provided is a silica-based polishing particle which can polish and flatten the surface of a substrate at a sufficient polishing rate with generation of scratches prevented, and successfully prevents generation of particle residues on a substrate after polishing. A silica-based polishing particle with a three-dimensional polycondensation structure containing an alkoxy group, wherein the particle has an average particle diameter (d) of 5 to 300 nm, an aspect ratio of 1.00 or more and 1.20 or less, and a carbon content of 0.005% by mass or more and less than 0.50% by mass.

A process is provided for preparing an inorganic material in the form of an alveolar monolith of a silica matrix where the monolith includes interconnected macropores. The process includes at least one step of mineralizing an oil-in-water emulsion formed from droplets of an oily phase dispersed in a continuous aqueous phase and in which colloidal solid particles are present at the interface formed between the continuous aqueous phase and the dispersed droplets of oily phase. Such materials obtained according to this process may be used, especially for separative chemistry and filtration, for performing chemical reactions catalyzed in heterogeneous phase, as thermal or phonic insulators, or as templates for manufacturing controlled-porosity carbon skeletons.