Research On Flotation And Purification Of Low Grade Magnesite

Magnesite is a very important non-metallic mineral. And it is widely applied in metallurgic, building materials, chemical industry and so on. Low grade magnesite can't be used directly as material of refractory, and along with the continuously mining, the reserves of high grade magnesite becomes less and less. Therefore, for better utilization the resources, it is necessary to find a purification method, which is suitable for low grade magnesite.The research used two kinds of low grade magnesite as the material. And by flotation test and process present situation analysis, reasonable flotation technological process can be chosen. The aim to purification and desilication can be realized. This paper, according to studing the behaviours of lauryl amine (cationic collector) and sodium oleate (anion collector) in the flotation separation of quartz and magnesite, choosed the suitable agentia and technological process to realize the aim to desilication. And the research included floatability test of single mineral, flotation separating experiment of man-made mixed minerals using anion and cationic collector and flotation separation test of the natural ore. In addition, the flotation mechanism of lauryl amine and sodium oleate and the main inhibitor were also discussed.The result of the floatability test of single mineral show that, on neutral and basic condition, magnesite and quartz had different planktonic in lauryl amine system. So, the reverse flotation was usually applied in desilication of magnesite on weak basic condition. And in sodium oleate system using ammonium oxalate as inhibitor, quartz and magnesite had different planktonic. Thus, ammonium oxalate had selectivity inhibition to quartz with the pH value between 10 and 11,which is beneficial to flotation of magnesite.The desilication experiment of man-made mixed minerals used cationic reverse flotation process and anion positive flotation process, respectively. The results showed that the man-made mixed minerals could be separated successfully by the two processes. But, in sodium oleate system, the flotation effect on the desilication experiment of natural ore wasn't very good. So, it needed further study. However, it fount that lauryl amine had good effect on desilication of the two kinds of natural ore. And the test results indicated that the grade of silica of concentrate could be decreased even to 0.6%, and the removing rate of silicon was more than 80%.The flotation separation of natural ore used lauryl amine as the collector. Then, the silicon was removed by the reverse flotation. And, on strong base condition, water glass combined with hexametaphosphate was used to inhibit the surplus silicate minerals and calcium minerals. In the end, the sodium oleate was used to the flotation of magnesite. The results showed that the grade of magnesium oxide was more than 47%, and the content of silica was less than 0.2% can be obtained. Therefore, the two kinds of natural ore can become the special grade product of magnesite. In addition, the recovery ratio of magnesium oxide of concentrate was 76.25% and 64.5%, respectively. The results showed the flotation flowsheet is applicable for the purification of magnesite in Dashiqiao and Haicheng areas.