In 1970, Japanese scholars studied the phase diagram of iron oxide microcrystalline formation, which laid a theoretical foundation for the preparation method of iron oxide yellow crystal seed. According to the research results, iron yellow crystal seeds can be formed under acidic or alkaline conditions. Because iron yellow is a crystal structure, in order to crystallize into pigment particles, it must first form crystal nucleus and become crystal seed, and then the crystal nucleus grows into iron yellow. Otherwise, only thin and dim color paste can be obtained, which does not have pigment properties. Acid process can be divided into iron sheet process and drop addition process.

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The FDA first approved the use of titanium dioxide in food in 1966, following its 1960 removal (along with the removal of other color additives) from the agency's original Generally Recognized as Safe list. In 1977, titanium dioxide joined the list of color additives that are exempt from certification, which means titanium dioxide doesn't have to be listed on the packaging of every product it's used in, Faber noted.

Lithopone

Le produit obtenu par cette méthode est constitué de 29,4 % en masse de ZnS et 70,6 % en masse de BaSO₄. Il existe des variations, par exemple l'adjonction de chlorure de zinc à la pâte avant chauffage produit un pigment plus riche en ZnS³.

Titanium IV oxide, also known as titanium dioxide, is a popular and versatile compound that is used in various industries. It is a white pigment and is commonly found in products such as sunscreen, paints, food coloring, and even in some medications. This versatile compound has unique properties that make it an essential ingredient in many products.

In May 2021, the European Food Safety Authority (EFSA) published an opinion that stated that titanium dioxide can no longer be considered safe when used as a food additive.

In a study published in 2022 in the journal Particle and Fibre Technology, researchers examined the impact of maternal exposure to titanium dioxide nanoparticles in newborn offspring mice. They found that “a chronic exposure to TiO2 NPs during pregnancy alters the respiratory activity of offspring, characterized by an abnormally elevated rate of breathing.” Breathing was also shown to be “significantly and abnormally accelerated,” and the ability for neural circuitry to effectively adjust breathing rates was impaired. The researchers concluded: “Our findings thus demonstrate that a maternal exposure to TiO2 NPs during pregnancy affects the normal development and operation of the respiratory centers in progeny.”

It’s produced through the sulfate or chloride process, which both involve treating titanium ore with sulfuric or hydrochloric acid to produce titanium sulfate or titanium chloride. These materials are then further processed to remove impurities and produce titanium dioxide in its final form.

JECFA also evaluated estimates of dietary exposure to titanium dioxide, estimating the maximum 95^th percentile of exposure to be 10 mg/kg BW per day. Overall, considering the low oral absorption of titanium dioxide as a food additive, the committee reaffirmed the ADI “not specified” that was established at the 13^th meeting.