Health advocates urge US regulators to ban common food coloring additive, by Tom Perkins, The Guardian, June 2, 2023
zinc sulfide content, %
Here, NaOH or NH3 · H2O is used as a precipitant or pH regulator to react with FeSO4 to form ferrous hydroxide precipitation; Air is used as oxidant; The iron sheet reacts with sulfuric acid produced during the oxidative hydrolysis of FeSO4 to provide ferrous ions required in the reaction system and maintain the pH value of the solution. The alkali consumption of acid method is less and the particles are easy to wash. The relative rates of seed preparation and crystal growth determine the particle size, particle size distribution and particle morphology of iron yellow particles.
Insolube matter in water
Titanium is one of the most common metals on earth, but it does not occur naturally in this elemental form. TiO2, also known as titanium (IV) oxide or titania, is the naturally occurring compound created when titanium reacts with the oxygen in the air. As an oxide, titanium is found in minerals in the earth’s crust. It is also found with other elements, including calcium and iron.