A kind of method for preparing titanium dioxide by alkali neutralization and external seed crystal

Abstract

The invention relates to the field of titanium dioxide production process, and in particular, relates to an alkali-neutralization seed crystal external addition method for producing titanium dioxide by a sulfuric acid method; a seed crystal preparation process comprises the steps: 1), metering and adding a concentrated titanium liquid into a seed crystal preparation tank; 2), under a condition of stirring, adding 100 g / L of an NaOH solution into the concentrated titanium liquid, and neutralizing with the neutralizing end point of pH=2.3-2.5; and 3), heating up to 65 DEG C, and carrying out heat preservation curing; and then cooling to 45 DEG for standby application; a hydrolysis process comprises the steps: 1), pre-heating 195-205 g / L of a titanium liquid in a titanium liquid preheating tank to 92 DEG C within 1 h; 2), inputting the pre-heated concentrated titanium liquid into a hydrolysis device, heating and keeping at the temperature of 92 DEG C; 3) adding a seed crystal within 5 min, at the same time, accompanying with stirring, wherein the seed crystal addition amount is 1.5% (the seed crystal TiO2:the titanium liquid TiO2); 4) heating within 20 min to make the concentrated titanium liquid boiled, and keeping boiling for 60 min; 5), adding 80 DEG C dilution water at uniform speed within 90 min, ensuring the slurry concentration after hydrolysis is finished is 160-170 g / L; and 6), finally keeping boiling for 50 min, and finishing the hydrolysis. The titanium dioxide prepared by the method has uniform particle size distribution, and pigment properties of the obtained pigment titanium dioxide primary product are not bad.

Description

technical field [0001] The invention relates to a production method for preparing titanium dioxide, which belongs to a method for preparing titanium dioxide by neutralizing an external crystal seed with alkali. Background technique [0002] At present, the industrial production of pigment titanium dioxide at home and abroad mainly adopts the sulfuric acid method and the chlorination method. In China, the sulfuric acid method is still the main method, which is divided into spontaneous seed crystal thermal hydrolysis and external seed crystal thermal hydrolysis. One of the key factors that determine the hydrolysis rate, the washing efficiency of metatitanic acid and the quality of pigment titanium dioxide are the hydrolysis conditions and hydrolysis operation, the quantity, quality and dispersion of the seed crystals formed in the initial stage of hydrolysis in the autogenous seed crystal hydrolysis process The situation plays a decisive role in the metatitanic acid structure,...

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