What are the key quality grades and purity standards for potassium carbonate in Chinese industrial markets?

Chinese potassium carbonate producers are increasingly segmenting their offerings by purity and application. The national standard GB/T1587-2016 defines multiple grades, with Type I premium products requiring ignited main content of at least 99.8%. Leading domestic manufacturers now supply this high-purity grade for optical glass, display panels, and fine chemical synthesis where trace impurities like chlorides and heavy metals can compromise product performance. For civilian glass and fertilizers, Type I first-grade or qualified-grade products at the same 99.8% ignited content but with less stringent impurity limits offer cost savings. One Jiangsu producer has built a 50,000-tonne annual capacity line for premium anhydrous potassium carbonate, reducing import dependence for high-end applications. The market now offers a clear ladder from agricultural-grade (cost-optimized) to premium optical-grade (performance-driven), enabling buyers to match specifications precisely to their process requirements.