The process flow for preparing pharmaceutical and food grade heavy magnesium carbonate from hydromagnesite is as follows:
① Raw material preparation: crush and screen the hydromagnesite to obtain magnesite powder with a particle size of 0.5-2mm.
② Calcination: Calculate magnesite powder at 800-900°C to obtain calcined magnesium oxide.
③ Water-soluble: Dissolve the calcined magnesium oxide in water to obtain a magnesium bicarbonate solution.
④ Precipitation: Add a precipitant to the magnesium bicarbonate solution to form a precipitate of hydrated basic magnesium carbonate.
⑤ Filtration: Filter the precipitated hydrated basic magnesium carbonate to obtain a filter cake.
⑥ Drying: Dry the filter cake to obtain heavy magnesium carbonate.
The characteristics of this process are:
① The sources of raw materials are wide and the cost is low. Hydromagnesite is an important non-metallic mineral with abundant reserves and wide distribution.
② The process is simple and the operation is convenient. This process uses conventional chemical processes, is simple to operate, and is easy to implement industrial production.
③ Product quality is excellent. Heavy magnesium carbonate has good physical and chemical properties and is suitable for use in the pharmaceutical and food industries.
The specific process parameters are as follows:
Magnesite calcination temperature: 800-900℃
Solubility of calcined magnesium oxide: about 10g/L
The amount of precipitant used: 0.4-1.2 times the molar number of MgO in the magnesium bicarbonate solution
Filtration time of hydrated basic magnesium carbonate: 1-2h
Drying temperature: 150-300℃
The quality standards for pharmaceutical and food grade heavy magnesium carbonate are as follows:
Moisture: ≤1%
Impurities: ≤0.1%
Particle size: ≤200μm
Loss on ignition: ≤10%
The heavy magnesium carbonate obtained by this process has good physical and chemical properties and meets the requirements of medical and food grade.
The improvement directions of this process mainly include the following aspects:
Improve raw material utilization. At present, in the production process of heavy magnesium carbonate, the filtrate of calcined magnesium oxide still contains a large amount of magnesium bicarbonate. By improving the process, the utilization rate of raw materials can be increased and the production cost can be reduced.
improve product quality. By optimizing process parameters, the particle size distribution, loss on ignition and other indicators of the product can be improved to meet higher requirements.
reduce manufacturing cost. Equipment investment and operating costs can be reduced by optimizing the process flow.
With the continuous advancement of technology, the process of preparing pharmaceutical and food-grade heavy magnesium carbonate from hydromagnesite will become more mature, the production cost will be further reduced, the product quality will be better, and it will have broad application prospects.