Process for reparation of rutile seed crystals from coarse-granularity hydrolysis abnormal material

Abstract

The invention relates to a process for preparation of rutile seed crystals from a coarse-granularity hydrolysis abnormal material. The process includes the following steps that a metatitanic acid hanging film as a coarse-granularity hydrolysis abnormal material is washed, beaten to 300-350 g / L and pre-heated, alkaline liquor is pre-heated according to the alkali-to-titanium ratio of (1.5-1.8):1, metatitanic acid is added for curing after pre-heating, water is added for dilution, alkaline liquor is cooled to be 70 DEG C, and a titanate is obtained; the hanging film is washed to obtain titanateslurry, hydrochloric acid is added to make the pH value become 2.8-3.1, the temperature rises to 60 DEG C, and the pH is adjusted to be 2.8-3.1 with hydrochloric acid; hydrochloric acid is added again, heating is performed until boiling occurs, the boiling state is maintained, water is added to be 95-105 g / L, and then the rutile seed crystals are obtained. The method is simple, the cost is low, the rutile conversion rate is high, the seed crystal storage time is long, when the seed crystals are used for preparation of titanium dioxide, the obtained titanium dioxide is small in particle size, the conversion rate is high, and the color index and the lightening power are significantly improved.

Description

technical field [0001] The invention relates to the field of titanium dioxide, in particular to a process for preparing rutile crystal seeds from hydrolyzed abnormal material with coarse particle size. Background technique [0002] The metatitanic acid obtained from the hydrolysis of titanium sulfate solution is amorphous, and the product can be completely converted into rutile crystal form by calcination at high temperature for a long time. However, during the calcination process, sintering will occur seriously, and there are many lattice defects, and the crystal grains are too large and hard, which makes the product gray. Therefore, in industrial production, it is necessary to add some rutile promoters and crystal form regulators to metatitanic acid to make TiO 2 It grows at a reasonable speed and produces pigment particles with complete crystal transformation, moderate size and regular shape at a lower calcination temperature. [0003] The rutile crystal seed is a rutil...

AI Technical Summary

Problems solved by technology

But using this method to prepare rutile-type calcined seeds has low activity, low rutile conversion rate of the seeds, and high oil absorption of the initial product. Also, zinc salts or other oxides are often added as auxiliary accelerators during salt treatment, making anatase TiO 2 It is completely transformed into a rutile structure, and the introduction of zinc increases the average particle size of titanium dioxide particles

[0005] The hydrolysis particle size of titanium dioxide produced by sulfuric acid method has a great influence on the pigment performance of titanium dioxide. If the hydrolysis produces coarse particles, if the material is directly mixed with normal hydrolyzed materials into the subsequent process, the adverse effects will inevitably be magnified, and the entire process will be affected. Indicators such as oil absorption, decolorizing power, oil phase whiteness, dry powder whiteness, etc. affect the finished product, and at the same time, it is also a big test for key equipment and operations such as rotary kiln

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