Preparation method of rutile type calcining seeds with high activity and high stability

Abstract

The invention discloses a preparation method for a rutile type calcination crystal seed with high activity and high stability, which comprises the following steps: (1) metatitanic acid and alkali liquid are respectively preheated and according to the ratio of 1.3:1-1.65:1 of alkali and titanium, the metatitanic acid is added into the alkali liquid in 30 to 55min to prepare ortho-titanate; (2) the obtained titanate is cooled and then washed in water with the temperature of 40 to 55 DEG C and changed into ortho-titanic acid; (3) the ratio of titanium and acid is controlled between 0.35 and 0.55, and hydrochloric acid is added into the ortho-titanic acid in two times, then PH value, temperature raising speed are controlled and the curing is carried out so as to obtain the rutile type calcination crystal with high activity and high stability. The method of the invention has obvious effect on inducing the metatitanic acid to be transformed into the rutile type when calcination is carried out, and the rutile transformation ratio of crystal seed is more than 99 percent; the rutile transformation ratio (R) of the obtained titanium powder is more than or equal to 98.7 percent; after crystal seed is placed for 6 to 10 days, the rutile transformation ratio (R) of the obtained titanium powder is still more than or equal to 98.6 percent.

Description

technical field [0001] The present invention relates to titanium dioxide (TiO 2 ) preparation technology, especially relates to the preparation method of the rutile type calcined seed crystal in the titanium dioxide preparation technology, the rutile type calcined seed crystal prepared by the method has the characteristics of high activity and high stability. Background technique [0002] In the preparation process of titanium dioxide (titanium dioxide), the calcined seed crystal is a microcrystal with a rutile structure, which promotes the transformation of titanium dioxide from anatase to rutile, thereby reducing the crystallization rate. Transformation temperature, improve the quality of seed crystal formation. To convert metatitanic acid into rutile titanium dioxide without adding calcination seeds, the calcination temperature needs to be increased to above 1000°C; however, after adding calcination seeds, the temperature can be reduced to 870-950°C, which not only reduc...

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Problems solved by technology

The alkali-titanium ratio used in the patent application document "200410045037.2" is 1.7:1~1.9:1, which is too high and consumes a lot of lye

The patent application document "200410021767.9" reacts metatitanic acid with sulfuric acid, and then adds the prepared titanium solution into the lye solution. This method adds an acid hydrolysis process and requires additional equipment, which is not conducive to on-site guidance.

In addition, the concentration of lye used by many manufacturers is ≥48%, which increases the production cost, and the feeding time of metatitanic acid is relatively short (10-25min), which is not conducive to the full reaction of metatitanic acid and lye

There are also some manufacturers whose parameter control is inaccurate, such as: the speed of peptization heating fluctuates greatly, resulting in unstable quality of seed crystals and low activity

It is understood that the rutile conversion rate of the seeds prepared by many manufacturers fluctuates between 70% and 98.5%, and the pass rate of the seeds (ie: the proportion of R% ≥ 98%) is less than 50%.

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