What are the main production routes for potassium thiocyanate in China?

What are the main production routes for potassium thiocyanate in China?
Chinese manufacturers employ three principal routes for potassium thiocyanate synthesis. The first involves reacting potassium cyanide with sulfur under heating, followed by water extraction, filtration, and concentration. This method is straightforward but carries handling risks associated with cyanide feedstocks. The second route uses ammonium thiocyanate with lime milk and potassium sulfate, offering a safer alternative. The third combines ammonium thiocyanate with potassium carbonate or potassium hydroxide. Process economics vary by feedstock availability and regional environmental regulations. Cyanide-based routes face tightening scrutiny due to safety and waste concerns, pushing some producers toward thiocyanate-exchange methods. Product purity typically ranges from below 99% for industrial applications to 99% and above for analytical and specialty uses. The choice of route also influences impurity profiles—particularly heavy metals and residual ammonium—which determine suitability for high-end applications like pharmaceuticals or electronics-related uses.