Light magnesium oxide is a kind of white powder with large apparent specific volume, light weight, loose and insoluble in water. It is widely used in the fields of ceramics, refractory products, adhesives, paint fillers, rubber promoters and activators, medicine, glass, plastics and food.
Salt lake resources are rich in our country, and in chaerhan salt lake of qinghai salt lake in xinjiang lop nur were systematically stud Ed magnesium resources to be developed, therefore, the development of the preparation of magnesium oxide magnesium salt lake resources can not only promote the comprehensive utilization of salt lake, can solve the present solid magnesite dry up again, the plight of magnesium products grade is declining, and at the same time can greatly alleviate the result of the development of potash industry "magnesium pollution", and bring huge economic benefits and social benefits.
Magnesium oxide precursor was prepared from the subtype sulfate salt lake brine in Lopp Nor, Xinjiang by ammonia method, and then high purity and light magnesium oxide was prepared by carbonization calcination. A new three-step process of magnesium precipitation by ammonia method, ammonium bicarbonate carbonization and calcination was established.
Experimental results show that ammonium bicarbonate carbonization of magnesium oxide can effectively reduce the content of S and B in magnesium oxide products, improve the apparent specific volume and purity of magnesium oxide.
The purity of high purity light magnesium oxide products was obtained under the optimum technological conditions >99%, visual volume up to 10mL/g, the main indicators up to HG1-324-77 special indicators.
Magnesium oxide precursor was prepared from magnesite chlorite from Qarhan salt lake in Qinghai Province with lime water as precipitator. High purity and light magnesium oxide was obtained after carbonization and calcination. A new three-step process of magnesium precipitation by lime water, ammonium bicarbonate carbonization and calcination was established.
To whitewash the preparation of magnesia calcium chloride mother liquid circulation in the process of preparation of limewater involves a CaCl2 - Ca (OH) 2 - H2O system has carried on the theoretical research, draw the Ca (OH) 2 - H2O system at 273.15 K under the condition of thermodynamic equilibrium log c - pH figure, find out the pH and concentration of CaCl2 Ca (OH) 2 for the lime water solubility, the effects of using the debye Hugh Kerr law limit calculation of the concentration of calcium chloride and calcium hydroxide concentration, and found that the experimental values and calculated values.When calcium chloride mother solution concentration >;When 2.5720Mo1/1, there is CaClOH phase, which cannot be used to prepare lime water. According to calculation, the mother liquor of calcium chloride can be recycled to prepare lime water 132 times.
The results show that the bidirectional synthesis method is the best, and the increase of mass percentage concentration and volume of calcium chloride is beneficial to the decrease of supersaturation of the reaction system. The content of impurities in magnesium oxide prepared by lime water method is much lower than that of traditional lime milk method, and the purity of magnesium oxide prepared by lime water method can reach over 99% after washing.
Magnesium oxide prepared by continuous experiment has good settling property and stable product quality. The apparent specific volume of magnesium oxide prepared by carbonization and calcination is effectively improved, with high purity and complete crystal shape, and the product quality reaches the HG1-324-77 special index.