Abstract: Systematic study on the property and processing of a low-grade magnesite from Haicheng in Liaoning province was conducted, aiming at its problems of high silicon, high calcium and high iron in mineral processing. The results showed that: the final magnesite concenrate with MgO content of 47.13%, CaO content of 0.21%, SiO₂ content of 0.18%, Fe₂O₃ content of 0.30% and MgO recovery of 60.21% was fininally achieved by the process of desiliconizing with reverse flotation-decalcification and magnesite enrichment with positive flotation-iron removal with high intensity magnetic separation on a magnesite with high silicon, high calcium and high iron. The results not only reach the purpose of desiliconizing, decalcification and iron removal, but also have guiding significance for full utilization this type of magnesite.

Key words: Low-grade magnesite, High silicon, High calcium, High iron, Reverse flotation, Positive flotation, High intensity magnetic separation