This precipitate is not suitable for a pigment until it is filtered, dried, crushed, heated to a high temperature and quenched in cold water. The second heating in a muffle furnace at 725 °C produces crystals of the right optical size.
However, it’s also important to note that such adverse effects depend heavily on the form of the titanium dioxide. It can come down to characteristics like “particle shape, purity, surface charge, solubility, agglomeration rate, photo-activation, etc.”
The International Agency for Research on Cancer (IARC) has listed titanium dioxide as a Group 2B carcinogen — an agent that may be carcinogenic but lacks sufficient animal and human research. This has caused concern for its safety in food products (11, 12).
Lithopone B301, Lithopone B311 powder, C.I. Pigment White 5, is a mixture of inorganic compounds, widely utilized as a white pigment. It is composed of a mixture of barium sulfate and zinc sulfide. These insoluble compounds blend well with organic compounds and confer opacity. Lithopone B301, Lithopone B311 powder is famous for the cheap production costs, greater coverage. Related white pigments include titanium dioxide, zinc oxide (zinc white), and zinc sulfide
Natural barite and anthracite containing more than 95% barium sulfate are mixed and fed at a ratio of 3:1 (mass). After being crushed to a diameter of less than 2cm, it enters the reduction furnace. The furnace temperature is controlled to be 1000-1200°C in the front section and 500-500 in the back section. 600°C, the reduction furnace rotates at a speed of 80 seconds per revolution, and the reaction conversion rate is 80% to 90%.
Because of health risks, France banned titanium dioxide as a food additive in 2020. Two years later the European Union also banned titanium dioxide as a food additive.