Abstract: In the process of deep reduction， the particle size characteristics of iron particles have an important influence on subsequent sorting indexes. A vanadium-titanium magnetite concentrate in Panxi Area was regarded as object， and the influence of reduction temperature， reduction time and the amount of Na2CO3 mass ratio on the growth characteristics of iron particles were investigated through single factor condition test. The results showed that the amount of reduction iron in the samples increases， the metallization rate increases， and the size of iron particles increases with the increase of reduction temperature， reduction time and the mass ratio of Na2CO3. The reduction iron contents is 44.28% and the metallization rate is 86.84% with the reduction temperature of 1 000 ℃， the reduction time of 2 h and the mass ratio of Na2CO3 of 15%. The contents of particle over 19 μm is 53.29% and the contents of particle over 53 μm is 13.35% in the reduction condition. The recovery rate of metallic iron could reach more than 93% after further grinding and magnetic separation. Iron particles grow up through three stages of nucleation， growth and cooling in the process of deep reduction. In the end， more than 50% of iron particles formed by reduction form monomer， and a large amount of iron particles exist in the edge of mineral or the edge of internal pores， and a small amount of iron particles exist in the interior of mineral particles.

Key words: vanadium-titanium magnetite, deep reduction, single factors condition tests, Na2CO3 mass ratio, metallization ratio, SEM analysis