关键词: 铁精矿降硅, 弱磁精选, 低场强高梯度磁选, 细筛分级, 再磨再选, 弱酸性正浮选

Abstract: In order to provide technical support for silicon reduction from iron ore concentrate in dressing plant of Meishan Iron Mine，based on identifying reasons for high content of SiO₂ in on-site iron ore concentrates，beneficiation tests on the on-site sulfur floating tailings is made by adopting four schemes to obtain iron concentrate with SiO₂ content of less than 4%.The results show that option 1 is adding the clean low intensity magnetic separation into the site process and adopts low field into high gradient magnetic separation.Option 3 adopts the process of low intensity magnetic separation-high gradient magnetic separation-fine sieve-regrinding and re-concentration of oversize products.And，option 4 consists of low intensity magnetic separation-high gradient magnetic separation-acidulous positive flotation.All of option1,3 and 4 can realize the iron ore concentrate with SiO₂ content <4%.But in option 1，iron ore concentrate is obtained with a relatively high grade iron ore and low iron recovery.In option 3 and 4，iron recovery rate is relatively high and-iron grade is relatively low.So,what kind of option being adopted should be determined through further expanding industrial tests.

Key words: Silicon reduction for iron ore concentrate, Clean low intensity magnetic separation, High gradient magnetic separation with low field strength, Fine sieve, Regrinding and re-concentration, Acidulous positive flotation