The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 22, 1995
Filed:
May. 24, 1993
Saila Karvinen, Pori, FI;
Kemira Oy, Helsinki, FI;
Abstract
The invention relates to a method of preparing microcrystalline titanium dioxide, in which a) the solid titanium dioxide hydrate is treated with a base, b) the precipitate treated with the base is treated with hydrochloric acid, and c) the precipitate treated with the base and the hydrochloric acid is neutralized. It has been noted that useable rutile crystals, a more appropriate crystal size and crystal size distribution and that chemicals can be saved if as the final hydrochloric acid content of the stage a) is adjusted a lower value than usually, being about 8 to 25 g/liter, for the precipitation of microcrystalline titanium dioxide. Hereby the neutralization of the stage c) can also be carried out by raising the pH to a lower value than usually, i.e. the value about 4.0 to 6.0.