Purification and recovery of dense medium by magnetic separation ,which plays a key role in maintain the density stability of the fluidized bed and continuous separation ,is one of important process in air dense medium fluidized bed coal beneficiation .On the basis of size properties requirements of fluidized magnetite powder used as dense medium in air dense medium separation ,through comparative analytical method influencing factors of magnetite powder and magnetic separation process were evaluated from the respective of the parameters such magnetic susceptibility ,particle size ,density and so on ,which have an effect on purification and recovery of magnetite powder by dry magnetic separation .And moisture of magnetite powder in dry magnetic separation was discussed .Then the problems of being paid more attention to in dry magnetic separation were presented such as moisture ,size ,content ,used conditions and so on .The results show that differences in magnetic susceptibility ,particle size and density between magnetite powder and fine coal ,this provides advantages in magnetic separation .Application feasibility of purifying and recovering magnetite powder by dry magnetic separation is feasible with being controlled moisture .There must choose or design suitable magnetic separator and simultaneously carried out more research to determine the optimum operating parameters .%干法磁选净化回收加重质是空气重介质选煤工艺系统的重要环节之一，其对调控分选系统自身密度和维持连续性运行起着关键作用，在介绍空气重介质选煤中常用磁铁矿粉加重质流化特性对粒度要求的基础上，采用对比分析法对影响干法磁选磁铁矿粉的磁性质、粒度、密度等物性因素进行了分析；探讨了水分对干法磁选净化磁铁矿粉的不利影响；并指出了需要特别注意外在水分、粒度、磁性物含量、使用环境与湿法磁不同等问题。分析表明磁铁矿粉和煤粉在磁系、粒度、密度的差异显著，这为干法磁选净化磁铁矿粉提供了有利条件；在适当控制水的分前提下，应用干法磁选净化回收磁铁矿粉的技术可行，建议选择适宜或专门设计此方面的磁选机，并针对这些影响因素进一步开展参数优化实验研究。
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