反应详情

Referring to FIG. 1, titanium ore 2 (typically, ilmenite) is digested with sulfuric acid 4 at temperatures greater than 100° C., then leached with water or dilute acid to produce a solution 6 of titanium sulfate and iron sulfates, also referred to as a “black liquor”. The solution 6 is cooled to a temperature of about 65° C. and clarified, and iron sulfates are separated from the solution 6 by crystallization 8. Scrap iron may be added at this stage of the process to reduce ferric sulfate to the less soluble ferrous sulfate 10, thus promoting separation of the iron sulfates by crystallization 8. The hydrolysis of the titanium sulfate is performed next, typically in the same stage as the precipitation 12 of the titanium oxide. Precipitation 12 is achieved by boiling the solution 6 for a number of hours. The conditions of precipitation 12 are controlled so that the precipitate can be easily filtered and washed 14, and to produce crystals that will have the correct crystal structure and crystallite size after calcination 16. The washing step 14 removes any soluble metal salts that may remain and reduces the sulfuric acid content of the resulting slurry. During calcination 16, the titanium oxide slurry is heated to temperatures in the region of 700-1000° C. in air to drive off water and sulfur oxides, and to control the crystal size of the titanium oxide 18 produced. The final stages of calcination 16 may be performed so as to convert the crystalline product to rutile structure. The resulting titanium oxide 18 is then finished 20 in a series of processes that provide the desired properties to the titanium oxide product.

1. additiondilute acid