2. Barite calcination method A solution of barium sulfide is prepared. The sulfuric acid and zinc oxide are reacted, purified by adding potassium permanganate and zinc powder, and compressed to obtain a zinc sulfate solution. Then, the prepared barium sulfide solution is mixed and subjected to a metathesis reaction to obtain a mixture of zinc sulfide and barium sulfate, and then the precipitate is subjected to pressure filtration, calcination, wet grinding, drying, and pulverization to obtain a zinc white product.

Additionally, the committee noted that the available data did not provide convincing evidence of genotoxicity for titanium dioxide as a food additive, but recognized the limitations in current methodologies with respect to the testing of poorly soluble particulate materials. Although there were uncertainties in the genotoxicity data, the experts took into account the fact that the additive was not carcinogenic in adequately conducted two-year studies in mice and rats at doses of up to 7,500 mg/kg BW per day for mice, and 2,500 mg/kg BW per day for rats, the highest doses tested. There was also no evidence of reproductive or developmental toxicity in studies in rats at doses up to 1,000 mg/kg BW per day, the highest doses tested.  

Lithopone was developed in the 1870s as a substitute for lead carbonate (lead white), to overcome its drawbacks of toxicity and poor weathering resistance. Within a few years, titanium dioxide displaced lithopone to become the white pigment (PW6) par excellence in the industry and the world’s best-selling inorganic pigment. However, titanium is a product whose price is subject to large price variations due to product availability. These price increases affect the competitiveness of finished products, and so the search for an alternative to titanium dioxide has generated a variety of possibilities to optimise its use.