The Application of titanium dioxide in paper making.
Paper making is the third largest user of titanium dioxide. Titanium dioxide is generally used in decorative paper, Bible paper and banknotes. Paper using titanium dioxide has good whiteness, high strength, luster, thin and smooth, and does not penetrate during printing. Under the same conditions, opacity is 10 times higher than calcium carbonate and talcum powder, and the weight of the paper can be reduced by 15% to 30%.
Decorative paper, also known as titanium paper, is mainly used to make raw materials for furniture, flooring, wallpaper, etc. For papers with anti-aging requirements, rutile must be used; more rutile is used in high-ash paper. This high-ash paper must use rutile because the hiding power of anatase titanium white is not achieved.
Anatase titanium dioxide is used in low-ash paper, such as Bible paper and banknotes. Bible paper requires good opacity of paper, generally using anatase titanium dioxide; coinage paper is also required Good opacity, mainly using anatase. In China, the amount of titanium white used in decorative paper is much higher than the other two varieties. This situation is determined by the level of consumption in China. According to incomplete estimates, the domestic titanium dioxide used for decorative paper exceeds 30,000 tons per year.
The requirements of paper making industry on titanium dioxide:
Firstly, Covering power (opacity): The ability of covering the background color, compared under the same content of titanium dioxide in paper. This indicator determines the price/performance ratio of titanium dioxide. Simply, titanium dioxide with high hiding power is generally expensive, but the amount of use is small, so the cost of titanium dioxide per ton of paper may be lower; titanium dioxide with low hiding power, although low in price, but large in amount, resulting in per ton The cost of titanium dioxide in paper increases;
Secondly, the whiteness: the whiteness of titanium white determines the appearance of the paper after molding;
Thirdly, the dispersibility: the current paper making process generally uses a dispersant, therefore, the water dispersion of titanium dioxide is not much different;
Fourthly, weather resistance: domestic rutile can meet the weathering performance requirements of most papers, only a small amount of paper requires rutile to provide high weather resistance;
Fifthly, Retention rate: The paper industry reuses the filtered water, or uses a retention aid. Generally, the recovery rate of titanium dioxide is above 99%. The reason for retaining this indicator is because the international large titanium dioxide company is selling. When the titanium dioxide for paper making is used, both the retention agent formulation and the use method are provided to improve the service quality and increase the competitiveness of the product.