Abstract: Coated titanium dioxide particles are provided and made from a method wherein a zirconium oxide coating and an aluminum oxide coating are formed on the surface of titanium dioxide particles. The zirconium oxide-forming and aluminum oxide-forming coating materials can be used to control the pH of the surface treatment process without the need for adding pH controlling agents.

Abstract: A method of preparing coated titanium dioxide particles is provided. The method can include forming an aqueous suspension of titanium dioxide particles having a pH of from about 5.0 to about 7.0; adding a zirconium oxide-forming solution to the suspension in an amount sufficient to decrease the pH of the suspension to about 4.0 or lower; forming a zirconium oxide coating on the titanium dioxide particles to form a suspension of coated particles; adding an aluminum oxide-forming solution to the suspension of coated particles in an amount sufficient to increase the pH of the suspension to about 9.0 or higher; and forming an aluminum oxide coating on the coated particles to form a product.

Abstract: Sodium silicate solutions of modulus 3.0 to 3.8 are provided. In some embodiments, the solution is made by a process that uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: Sodium silicate solutions of modulus 3.0 to 3.8 are provided. In some embodiments, the solution is made by a process that uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A method of preparing coated titanium dioxide particles is provided wherein a zirconium oxide coating and an aluminum oxide coating are formed on the surface of titanium dioxide particles. The zirconium oxide-forming and aluminum oxide-forming coating materials can be used to control the pH of the surface treatment process without the need for adding pH controlling agents.

Abstract: A method is provided for treating silica sand scrubs (SSS) generated and accumulated as waste in the chloride manufacturing process of titanium dioxide pigment. A hydrothermal process is used to produce sodium silicate solutions of modulus 3.0 to 3.8, and precipitated silicas. In some embodiments, the process uses two specific principal reaction stages. A sodium silicate solution having a low SiO2:Na2O molar ratio, in the range from 2.0 to 2.8, is first produced by reaction of the SSS, as a cost-effective SiO2 source, with aqueous caustic soda. The conversion of this intermediate sodium silicate solution of low modulus to a high SiO2:Na2O molar ratio is made possible by using a SiO2 source that is prepared as precipitated amorphous silica from the intermediate sodium silicate solution produced above.

Abstract: A process for producing an improved titanium dioxide pigment composite is provided, as are particles produced thereby. The process comprises producing a slurry comprising titanium dioxide particles, leaching alumina from the surface of the titanium dioxide particles in the presence of a soluble phosphate and precipitating aluminum phosphate from the slurry onto the surface of the titanium dioxide particles thereby forming a uniform coating of aluminum phosphate on the surfaces of the titanium dioxide particles. An anionic poly-electrolyte can be added to the resulting slurry. The slurry can then be treated such that the anionic poly-electrolyte forms an additional coating on the aluminum phosphate-coated titanium dioxide particles.