| 摘要 |
1335537 Ti sulphate hydrolysis DOWUNQUINESA SA 20 Nov 1970 [22 Nov 1969] 55358/70 Heading C1N In a process for producing TiO 2 by hydrolysis of a seeded Ti sulphate solution, the solution is heated at or below its b.pt. with agitation while its reflectance is continuously monitored, and after the curve of reflectance against time has reached a point of inflection, agitation and heating are preferably stopped for 5-60 mins., and then heating is resumed with simultaneous dilution. The reflectance may be measured by means of a photo-electric cell, the critical point causes a change in control current which initiates the further series of operations. The seeds may be prepared separately, or in situ, e.g. by slowly adding the solution to water, both at 90-100‹ C. The solution may initially contain 100-300 g./l. TiO 2 and be diluted to 140-180 g./l. The product may be treated with K 2 SO 4 and calcined. |
