Scrap zinc or concentrated zinc ores are dissolved in sulfuric acid, the solution is purified, and the two solutions are reacted. A heavy mixed precipitate results that is 28 to 30% zinc sulfide and 72 to 70% barium sulfate.

Sulphate process. The ilmenite is reacted with sulphuric acid giving titanium sulphate and ferric oxide. After separation of ferric oxide, addition of alkali allows precipitation of hydrous titanium dioxide. The washed precipitate is calcined in a rotary kiln to render titanium dioxide. The nucleation and calcination conditions determine the crystalline structure of titanium dioxide (e.g. rutile or anatase).

Titanium dioxide A1 adopts good oxidation process, composite inorganic coating and organic treatment, and has the characteristics of excellent particle size distribution, high brightness and high weather resistance. It is recommended for high gloss and high weather resistance coatings, inks and outdoor polymer materials.

When E171 isn’t combined with other ingredients and administered in water, some studies suggest that under these artificial conditions, E171 may be processed differently in the body resulting in some biological changes in experimental animals that are poorly understood.

But this is just the tip of the ice berg so many articles & studies are coming out challenging the safety of Titanium Dioxide in our food supply & personal care products.

Overall, the Food Directorate's comprehensive review of the available science of TiO₂ as a food additive showed:

Absorption

In a 2016 study published in Scientifica (Cairo), Egyptian researchers examined the effects of titanium dioxide nanoparticles on the organs of mice by orally administering the food additive daily, for five days. The results showed that the exposure produced “mild to moderate changes in the cytoarchitecture of brain tissue in a time dependent manner.” Furthermore, “Comet assay revealed the apoptotic DNA fragmentation, while PCR-SSCP pattern and direct sequencing showed point mutation of Presenilin 1 gene at exon 5, gene linked to inherited forms of Alzheimer’s disease.” The researchers wrote: “From these findings, “the present study concluded that TiO2NPs is genotoxic and mutagenic to brain tissue which in turn might lead to Alzheimer’s disease incidence.”

Does not work with hydrogen sulfide and alkaline solutions. It is easy to decompose in the presence of acid to produce hydrogen sulfide gas. It is easily oxidized in the air and deteriorates after moisture. Whiteness and hiding power are strong.

The trouble with titanium dioxide, by Siloam Springs Regional Hospital, Herald Leader, October 4, 2023

Titanium dioxide exists primarily in three crystalline forms rutile, anatase, and brookite. Among these, anatase is characterized by its unique electronic properties and higher photocatalytic activity, making it suitable for applications requiring enhanced light absorption and reactivity. Its ability to act as a photocatalyst enables the breakdown of organic pollutants, making it a valuable component in environmental remediation strategies.

Lithopone was discovered in the 1870s by DuPont. It was manufactured by Krebs Pigments and Chemical Company and other companies. The material came in different seals, which varied in the content of zinc sulfide. Gold seal and Bronze seals contain 40-50% zinc sulfide, offering more hiding power and strength. Although its popularity peaked around 1920, approximately 223,352 tons were produced in 1990. It is mainly used in paints, putty, and in plastics.