Experimental study on reduction of ultra-fine hematite powder at non-molten state

The reduction degrees of ultra-fine hematite powder(the average particle size is 2μm) and conventional hematite powder(the range of particle size is 0.18 to 0.154mm) in non-molten process were studied.Taking the reduction degree of hematite powder as a target and according to the transformed L₁₆(2¹⁵) orthogonal table,a series of 4×2³ times experiments were arranged to eliminate the interference of reduction atmosphere,reduction temperature and reduction time.The results show that ultra-fine hematite powder can be reduced from Fe₂O₃ to Fe at different degrees.Compared with conventional particle size hematite powder,ultra-fine hematite powder has a higher reduction degree,and the reduction temperature required to access the same reduction degree lowers about 365 ℃ under the condition of 650 to 850 ℃ and pure H₂ or 100% CO atmosphere.There is no correlation among these factors,the quantitative impact of them can be separately estimated,and this provides a basis for establishing an equation of linear regression for each of them.After reduction at non-molten state,the particle size distribution of hematite powder indicates that inter-particle sintering does not occur and the reduction product is still powdery.