White crystalline powder. It is a mixture of zinc sulfide and barium sulfate. The more zinc sulfide it contains, the stronger the hiding power and the higher the quality. Density 4.136～4.34 g/cm3, insoluble in water. It easily decomposes when exposed to acid to produce hydrogen sulfide gas, but does not work when exposed to hydrogen sulfide and alkaline solutions. It turns into light gray after being exposed to ultraviolet rays in the sun for 6 to 7 hours, but it still returns to its original color when placed in a dark place. It is easy to oxidize in the air and will agglomerate and deteriorate when exposed to moisture.

Lithopone 30% CAS No. 1345-05-7 / Physical data

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.

Example of partial substitution of titanium dioxide with lithopone supplier 30% in a white masterbatch