Study On Test Of Purification Low-grade Magnesite By Selective Leaching Method

China is the most rich on the magnesite resource reserves country in the world, magnesite reserves of3billion tons, accounting for a quarter of the world’s total reserves. The advantage of mineral resources makes our country becomes a major exporter of magnesium salt products. However, with the rapid development of our economy, magnesite resource consumption is increasing rapidly, can satisfy the industrial production of magnesite mineral resources reserves in a sharp decrease. A large number of low grade magnesite (MgO content of35%to42%) due to cannot be used directly as the raw material of preparing the refractory is discarded, causing mineral tremendous waste of resources and serious pollution of the environment. Our country low grade magnesite accounted for about a third of magnesite total reserves, about840million tons, and how to realize the effective development and utilization of low grade is needed to solve the problems in the process of development and utilization of magnesium salt products.In view of the above questions, the paper intends to low grade magnesite as raw materials, and carry on the comprehensive utilization of research, the main research contents are as follows:(1) Low grade magnesite the hydration test research:low grade magnesite after calcination, grinding, after a light burning prepared light-burned magnesium oxide powder, and then carry on the hydration test. Mainly studied the ore particle size, reaction concentration, reaction temperature and reaction time influencing factors, and finally determine the best hydration test conditions. Under these conditions, hydration rate of the hydration products reached92%.(2) Low grade magnesite carbonated test research:The light burned magnesium oxide powder direct carbonation trial, mainly studies the reaction concentration, raw material particle size, stirring speed, carbon dioxide pressure and reaction time and so on factors, and finally determine the best carbonated test conditions. Under these conditions, the carbonated product carbonate mineralization rate was90.3%.(3) Selective leaching study of filter cake:the carbonation test cake obtained by chemical precipitation method for the selective leaching, in accordance with the rules of the solubility product, The filter cake of silicon, iron, aluminum, magnesium, calcium in the form of silica, ferric hydroxide, aluminum hydroxide, magnesium hydroxide, calcium hydroxide sequential separation, through theoretical analysis and experimental product analysisand characterization, validation test the feasibility of the process and science.The thesis research will enable effective development and utilization of a large number of low-grade magnesite to change the current situation of China’s extensive use of low-grade magnesite, and that eases the shortage of high-grade magnesite resources, what laids the foundation for the production of high-end products. Meanwhile, the results will gradually solve mine pollution problems, and extend the mine life, which can greatly increases the economic efficiency of enterprises to promote the rapid development of our magnesium salt industry.