Preparation of High-Purity Titanium Salts from the System(NH4)2TiF6-(NH4)3FeF6-NH4F-H2O

摘要

Influence of NH4F concentration on the conditions of separation of Ti(IV)and Fe(III)salts by fractional hydrolysis under the action of ammonia in the system(NH4)2TiF6-(NH4)3FeF6-NH4F-H2O was studied.The coprecipitation of(NH4)3TiO2F5 and(NH4)3FeF6 as a result of crystallochemical substitution of Fe~(+3)for Ti~(+4)makes it possible to reduce the content of Fe(III)salts in the system.After separation of a precipitate containing up to 25% of Ti from solutions with NH4F concentrations from 10.6 to 22.3% and subsequent hydrolysis,the remaining titanium precipitates.The precipitate is annealed up to 800°C in the presence of water vapor to form TiO2 with a whiteness above 92%.