Chemical Composition:
Zinc Oxide (ZnO) Content: High purity is typically required, often exceeding 99%.
Lead (Pb): Should be minimal due to toxicity concerns, usually less than 20 parts per million (ppm).
Cadmium (Cd): Also minimized for safety reasons, typically below 10 ppm.
Iron (Fe): Should be low to avoid discoloration and unwanted chemical reactions, often below 50 ppm.
Other Impurities: Limits on elements like copper (Cu), manganese (Mn), and arsenic (As), depending on the application.