A kind of preparation method of rhombohedral anhydrous magnesium carbonate

Abstract

The invention provides a preparation method of rhombohedral anhydrous magnesium carbonate, which belongs to the technical field of new inorganic chemical materials, and is characterized in that the following steps are adopted: MgCl 2 ·6H 2 Add O into distilled water to prepare a solution with a certain concentration, and add CH at a certain molar ratio 4 N 2 O, stir to obtain a mixed solution; heat the configured mixed solution to carry out a pre-synthesis reaction, the reaction temperature is 80-95°C, and the reaction time is 1-2h; the mixed solution after the pre-synthesis reaction is moved to a tank with polytetrafluoroethylene Hydrothermal reaction in a lined stainless steel reactor, the temperature of the hydrothermal reaction is 140-150°C, and the reaction time is 2-4h; after the hydrothermal reaction is completed, the product is filtered and washed under negative pressure to obtain rhombohedral anhydrous magnesium carbonate; Anhydrous magnesium carbonate The rhombohedral anhydrous magnesium carbonate prepared in the present invention belongs to the trigonal crystal system, the side length of each rhomboid is 20-25 μm, and the rhombohedral particle size is 25-30 μm.

Description

technical field [0001] The invention relates to a preparation method of rhombohedral anhydrous magnesium carbonate, which belongs to the technical field of new inorganic chemical materials. Background technique [0002] Anhydrous magnesium carbonate is an important new inorganic chemical material, used as a pharmaceutical intermediate, antacid, desiccant, color-protecting agent, carrier, anti-caking agent, etc.; used as an additive and magnesium element compensator in food; Used as flame retardant, reinforcing agent, and filler in plastics and rubber; used in the manufacture of fire-resistant coatings, ink fillers, friction agents for toothpaste, etc. Different application fields have different requirements on the morphology and particle size uniformity of anhydrous magnesium carbonate, both of which will have a direct impact on its application fields and effects. [0003] At present, the synthesis methods of anhydrous magnesium carbonate mainly include: carbonization metho...

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Problems solved by technology

The synthesis temperature of this method is high, the reaction time is long, and the production cost will increase accordingly; the obtained crystal plane is multi-layered and sawtooth stepped, and the shape is incomplete, and the surface will peel off during the process of mixing with other materials, which will affect other materials. Process performance and product performance

[0006] In summary, in the existing anhydrous magnesium carbonate synthetic method, or adopt solvothermal method or hydrothermal method to add chelating agent, both need to use organic additive, influence product purity and increase cost; Or only use magnesium salt and precipitation If the agent hydrothermal method is used, higher synthesis stability and longer synthesis time are required

At present, there are very few relevant research reports on the synthesis of rhombohedral anhydrous magnesium carbonate with a single phase, good dispersion, uniform particle size, and complete crystal morphology at low temperature and short time without using organic solvents and chelating agents.

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