Method for preparing high-activity double-effect seed crystals from metatitanic acid

Abstract

The invention discloses a method for preparing high-activity double-effect seed crystals from an intermediate product, namely metatitanic acid, of titanium dioxide. The method comprises the following steps of: with metatitanic acid as a raw material, preparing clear titanium sulfate liquid, cooling the clear titanium sulfate liquid, adding a diluent of the clear titanium sulfate liquid to alkaline liquor, controlling pH value to 7.5-9.0, filtering and washing the obtained product, carrying out secondary washing on the washed product, carrying out acid dissolving on hydrofluoric acid and hydrochloric acid for short time under the lower temperature to obtain the high-activity double-effect seed crystals with hydrolyzed seed crystal performance and calcined seed crystal performance. According to the invention, the required titanium source is from the intermediate product produced from the titanium dioxide powder, therefore the method has low cost and production stability; in seed crystals, non-rutile promoted seed crystals and rutile promoted seed crystals are appropriate in proportion and have dual effects of hydrolyzed seed crystals and calcimined seed crystals; when the method is used for titanium dioxide production, calcined seed crystals are unnecessary to be additionally produced, the working procedure of adding the calcined seed crystals in the bleaching process is reduced, the bleaching time is shortened, and the rinsing efficiency is improved at the same time. The seed crystals prepared by using the method disclosed by the invention have high activity, excellent performance and capability of meeting hydrolyzing and calcining requirements just by adding 2 % of seed crystals.

Description

technical field

[0001] The invention relates to the technical field of titanium dioxide preparation, in particular to a preparation method with hydrolysis and calcination double-effect seed crystals in the production of titanium dioxide prepared from metatitanic acid. Background technique

[0002] In the production of titanium dioxide, the seeds of the hydrolysis method with external seeds need to be prepared separately. There are two types of hydrolysis seeds and calcined seeds. The hydrolysis seeds are added during hydrolysis, and the general size is below 10nm. Calcined seeds are added during bleaching. The general size is 80~120nm. The two have different structures and different roles, so the preparation process is also different. There are rutile-promoted and non-rutile-promoted hydrolyzed seeds, both of which are different and related. The connection is that both are a kind of colloid, which can be used as hydrolysis seed crystals to hydrolyze concentrated titanium s...

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