What are the key differences between fluorspar-acid and fluorosilicic acid routes for AHF production?

What are the key differences between fluorspar-acid and fluorosilicic acid routes for AHF production?
China's AHF industry has traditionally relied on the fluorspar-sulfuric acid route, requiring CaF2 content above 97%. With domestic fluorspar reserves tightening—China holds about 18.85% of global reserves but consumes roughly 60%—the industry is exploring alternative feedstocks. The fluorosilicic acid route, derived from phosphate fertilizer byproducts (H2SiF6), offers a green pathway that valorizes associated fluorine resources. However, this process faces significant operational challenges: the gas streams contain highly corrosive HF, SiF4, and HCl at high temperatures, making online monitoring essential. Traditional sampling is hazardous, and conventional analyzers fail under these conditions. Advanced Raman spectroscopy now enables real-time quantification of HF, SiF4, HCl, and H2O at reactor outlets, improving conversion efficiency and product purity. While the fluorosilicic acid route remains a small share of total capacity, its growth aligns with policy goals to reduce fluorspar dependence and utilize phosphate industry waste streams, particularly in regions with large phosphate fertilizer operations.