What are the key production technologies for magnesium carbonate and their cost implications?

What are the key production technologies for magnesium carbonate and their cost implications?
Industrial production of magnesium carbonate in China mainly uses three routes: soda ash method, lime method, and ammonium bicarbonate method. The soda ash process is mature and yields high-quality light magnesium carbonate, but it consumes large amounts of soda ash and fresh water, raising production costs. The lime method replaces soda ash with lime milk, reacting with magnesium chloride in brine to form magnesium hydroxide, then carbonating to magnesium bicarbonate. It lowers raw material costs but requires more complex equipment and generates large volumes of calcium chloride solution that needs disposal. Sulfate content in brine must be minimized to avoid calcium sulfate contamination. Some advanced producers, like Jiangsu Zehui, claim to use magnesium ingot and CO2 calcination technology, producing analytical-grade material with higher purity, lower impurities, and reduced production costs compared to traditional routes.