Application Study On Sintering Of Iron Concentrate Pretreated By High Pressure Roller Grinding

With the rapid development of China’s steel industry and the reduction of high-grade ore resources, iron ore imports are increasing, which influences China’s energy and industrial economic security. It is of profound significance to use the domestic-grown refractory iron concentrate of low cost and high-grade of iron to promise the sustainable steel industry of our country. There are lots of problems in sintering using iron concentrate, including low productivity, poor strength of sinter, high energy consumption and so on, thus using iron concentrates in sintering efficiently is becoming an inevitable tendency to develop the sintering processing.Focusing on the effects of High pressure roll grinding (HPRG) on the physical properties, granulation properties and mineralization performance of iron concentrate, iron concentrate of Yuanjiacun in Shanxi Province was investigated. Besides studying thoroughly the effects of those properties on mineralization performance in sintering using X-ray diffraction, laser particle size and optical microscopy, the process design and evaluation were developed, as well as the key influencing factors of HPRG on the enhancement of iron concentrate sintering were revealed.The specific surface area of iron concentrate increased and the particle surface activity and adsorption capability were both improved after HPRG pretreatment. The increasing specific surface area and iron fine concentrates are beneficial to improve the granulation properties and mineralization performance of iron concentrate. The contact angle of iron concentrate became smaller and its hydrophily was enhanced after HPRG. The particle morphology changed, forming rough surface with a lot of edges and sharp corners or neonatal surfaces after HPRG, which improved the activity of iron concentrate in granulation and assimilation. As improving granulation after HPRG, the granulation performance of quicklime&iron concentrate were best, iron concentrate only, return fines and reference experiment were worse in sequence. Compared to the reference experiment, the yield of sinter increased from63.33%to69.82%, the drum strength increased from49.35%to58.42%, and the utilization factor increased from1.559t·m2·h-1to1.762t·m2·h-1in the optimal experiment of sintering cup. It can be showed from the mineralogical phase that the yield and qualities of sinter were improved after iron concentrate was pretreated by HPRG. More compact of sinter, calcium ferrite increased, less holes and strength enhanced were the sinter product after HPRG with comparison to the iron concentrate with no HPRG.