How To Improve The Whiteness of Titanium Dioxide

    In the process of production and customer use, it is hoped that the whiteness of titanium dioxide can be higher. According to empirical analysis, when the whiteness of titanium dioxide increases, its hiding power and achromatic power indicators will also increase accordingly. Therefore, it is necessary to To achieve the same effect, less titanium dioxide is used, and the cost will be reduced. There are currently the following main methods for improving whiteness in production (for the sulfuric acid method).

1. Raw material selection

Raw materials are the first step in production. Only qualified raw materials can produce qualified products. Titanium dioxide is extremely sensitive to the content of impurities, sometimes as accurate as 1ppm. Therefore, choosing a good mineral source is a top priority. Iron, manganese, vanadium and niobium are important impurities, and their content needs to be strictly tested and precisely controlled.

2.Hydrolysis technology

Hydrolysis is an important process in the production process of sulfuric acid titanium dioxide, and it is also an important position that affects the whiteness of titanium dioxide. Usually, the uniformity of pressurized hydrolyzate products is poor, the washing speed is slow, and the whiteness of the finished product is poor. However, normal pressure hydrolysis can overcome this shortcoming, and the particle shape will be uniform and the whiteness will increase.

3.Calcination conditions

Calcining is a process of dehydration, desulfurization, crystal transformation, and crystal growth. It is directly related to the whiteness of the finished product. Do not under-burn or over-burn. Generally, a combustion chamber is set up in front of the rotary kiln to prevent the high-temperature flame from directly contacting the material, and the temperature, rotation speed and calcination time are controlled, and various parameters are controlled based on experience.

4.Sanding conditions

Sanding is the first operation in the post-processing stage, and its task is to break the material into pieces for later coating treatment. When the material is too coarse, the coating will be uneven. If the material is too fine, the hiding power of the finished product will decrease and grinding resources will be wasted. Therefore, the average particle size is generally controlled between 0.3 and 0.6 μm.

5.Coating process

The coating method, coating amount, and uniformity of the coating can all affect the whiteness of the product. Usually, coating with phosphorus, aluminum, and zirconium will tend to increase the whiteness, while coating with silicon will make the whiteness higher. The brightness remains unchanged or even decreases, and when the coating is uneven, it will seriously affect the whiteness of the finished product.