MAGNESIA PRODUCTION PROCESS Russian patent published in 2001 - IPC

FIELD: industrial inorganic synthesis. SUBSTANCE: magnesia feedstock is dissolved in stoichiometric amount of nitric acid (taking into account summary content of magnesium and calcium oxides) at 120-145 C and gage pressure 0.05-0.15 MPa. Magnesium hydroxide is precipitated by ammonia: first 10-15% of ammonia based on its total amount is fed at velocity 0.005-0.008 mole/min per 1 mole magnesium nitrate, after which 70-80% of ammonia is fed at velocity 0.01-0.04 mole/min per 1 mole magnesium nitrate. The rest of ammonia (10-15%) is fed at velocity 0.005-0.008 mole/min per 1 mole magnesium nitrate. Total amount of ammonia is equal to 2.2-2.5 mole per 1 mole magnesium nitrate. It is possible to use nitric acid and ammonia from ammonium nitrate production and also solutions of ammonium, calcium, and magnesium nitrates. Nitrose gases evolving on dissolution of magnesia feedstock are used for preparing nitric acid in ammonium nitrate production. Invention allows feedstock loss to be reduced by 5 times, whereas productivity is increased by 1.46 times. Invention can be utilized in production of transformer steel, rubber, perfumery products, pharmaceutical preparations, and plastics. EFFECT: enhanced process efficiency. 2 cl, 1 tbl