Hebei Messi Biology Co., Ltd. stated that magnesium carbonate is an important inorganic chemical material with good filling, dispersion and flame retardancy. Adding it to engineering plastics can significantly improve the flame retardant properties of engineering plastics. . At the same time, it can also be used as refractory materials, insulation materials for boilers and pipes, and in the manufacture of magnesium salt, magnesium oxide, ink, glass, toothpaste, etc. The so-called magnesium carbonate products currently on the market are mostly hydrated basic magnesium carbonate except for natural magnesite magnesium carbonate. In the existing production process of hydrated basic magnesium carbonate at home and abroad, the preparation of single-phase anhydrous magnesium carbonate has always been a challenge for chemists. There are very few patented technologies that can prepare single-phase anhydrous magnesium carbonate.
① Use soluble magnesium salts (such as magnesium chloride, magnesium sulfate, magnesium nitrate or magnesium acetate) and soluble carbonates (such as sodium carbonate, potassium carbonate or ammonium carbonate) as precipitants to prepare anhydrous magnesium carbonate in a solvothermal system. Solvents include absolute ethanol, ethylenediamine, etc.
② Use magnesium chloride and urea to synthesize single-phase magnesium carbonate in a hydrothermal system.
③ React magnesium chloride hexahydrate with ammonia and carbon dioxide in a certain ratio at normal pressure and room temperature to obtain magnesium ammonium carbonate tetrahydrate double salt precipitation, and then pyrolyze magnesium ammonium carbonate tetrahydrate at 80 to 390°C to obtain anhydrous magnesium carbonate. And the recycling process of carbon dioxide and ammonia.
④ Use magnesium chloride, ammonium carbonate and ammonium bicarbonate as precipitants, and use sodium hydroxide to assist the hydrothermal reaction to prepare single-phase anhydrous magnesium carbonate.
Most of the above preparation methods adopt hydrothermal or solvothermal preparation methods. The principle is to use certain ammonium salts that can form carbonate as precipitants or use organic substances such as absolute ethanol as solvents. Not only will side effects be produced during the production process, The production of ammonium chloride and ammonia pollutes the environment and is costly.
The invention provides a method for producing anhydrous magnesium carbonate by carbonization and anhydrous magnesium carbonate, which includes the following steps: preparing a reaction slurry with magnesium hydroxide and deionized water; driving the reaction slurry into a carbonization tower and feeding it into the carbonization tower. A phase transfer catalyst can be added to dissolve the salt solution of metal chloride, and then carbon dioxide is introduced to perform a carbonization reaction. After the carbonization reaction is completed, an anhydrous magnesium carbonate slurry is obtained; the anhydrous magnesium carbonate slurry is filtered to obtain anhydrous magnesium carbonate solid filter. Cake and filtrate; dry the solid filter cake of anhydrous magnesium carbonate to obtain anhydrous magnesium carbonate. The product prepared by the invention is single-phase anhydrous magnesium carbonate, has wide application fields, and the production process cost is low and green and environmentally friendly.