Zinc oxide is an amphoteric compound and can be combined with acidic substances through its basicity. In the combination of low acid index, zinc oxide produces zinc soap, which improves the wettability of the pigment, makes dispersion easier, and at the same time promotes a slight increase in coating viscosity and reduces precipitation. In high acid index adhesives, it will extremely thicken in the container.
Generally, lower grade zinc oxide is made by direct extraction of zinc ore, and its composition is still ZnO, but the grade is generally 45% ~ 65%. The so-called "second" refers to the grade. China's Guangxi, Guizhou, Yunnan, Hunan and other places have larger production. Its main purpose is to further process electrolytic zinc or zinc oxide.