Magnesium carbonate has a wide range of applications, primarily in industrial fillers, food additives, pharmaceutical antacids, and sports grip enhancers; specific purity levels and types are required depending on the application.
1. Roast a mixture of magnesite (MgCO₃) and coke to obtain magnesium oxide. Mix with water to form a slurry and bubble CO₂ through it to produce magnesium bicarbonate; filter the mixture and heat the filtrate to obtain a basic magnesium carbonate precipitate.
2. Gently heat dolomite (MgCO₃·CaCO₃) to decompose only the magnesium carbonate, then pulverize the product. React the powder with water and carbon dioxide at a pressure of 0.508–0.609 MPa; the magnesium oxide converts into soluble magnesium bicarbonate, leaving behind calcium carbonate. Finally, filter and heat the solution to obtain the product.
3. Dissolve equal amounts of crystalline magnesium sulfate and crystalline sodium carbonate separately in ten times their weight of water. Heat the solutions to 60–80°C and mix thoroughly; a precipitate forms concurrently with the evolution of CO₂ gas. Filter out the precipitate, mix it with hot water (70–80°C), and filter again. Repeat this washing process, and after thorough washing, dry the precipitate at 50–60°C.