| 摘要 |
The present invention relates to the manufacture of titanium dioxide wherein titanium sulphate liquor is produced containing colloidal and suspended impurities which are flocculated and removed from the liquor before the titanium dioxide is obtained by hydrolysis. More particularly it relates to the improvement of such manufacture comprising mixing the liquor, prior to hydrolysis, with a solution of (a) a polymer of an acrylic acid ester of the general formula: CH2=CR3COO(CH2)xNR1R2 wherein x is 2, 3 or 4, R1 and R2 are each selected from the group consisting of hydrogen and alkyl groups containing up to eight carbon atoms and R3 is a member selected from the group consisting of hydrogen and methyl, or (b) a water-soluble salt of said ester or (c) a copolymer of said ester with an ethylenically unsaturated comonomer, or (d) a copolymer of a water-soluble salt of said ester with an ethylenically unsaturated comonomer; the polymer or copolymer having a molecular weight such that the viscosity of a 1 percent by weight aqueous solution thereof as measured in a No. 3 Suspended Level Viscometer at 25 DEG C. is at least 40 centistokes, the comonomer being either water-soluble and present to the extent of not more than 40 percent by weight of the copolymer or water-insoluble and present to the extent of not more than 15 percent by weight of the copolymer.
|
