The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorizatiou agent were mixed and the mixtu...The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorizatiou agent were mixed and the mixture was then roasted in a tunnel kiln. The roasted products were treated by two stages of grind- ing followed by magnetic separation. XRD and SEM-EDS examination of the products was used to analyze differences in the roasted products. The results show that coal is one of the most important factors affect- ing the direct reduction roasting process. When the inner coal levels increased from 0% to 15% the iron grade decreased linearly from 94.94%to 88.81% and the iron recovery increased from 55.94% to 92.94%. At the same time the phosphorus content increased from 0.045% to 0.231%. Increasing the inner coal levels also caused more hematite to be reduced to metallic iron but the oolitic structure of the roasted product was preserved in the presence of high coal loading. The phase of the phosphorus in raw ore was not changed after direct reduction roasting. The effect of coal on the phosphorus content in the H-concentrate arises from changes in the difficulty of mechanically liberating the metallic iron from the phosphorus bearing minerals.展开更多
基金the National Natural Science Foundation of China (No. 51074016) for the financial support for this research
文摘The effect of coal levels on phosphorus removal from a high phosphorus oolitic hematite ore after direct reduction roasting have been investigated. Raw ore, coal, and a dephosphorizatiou agent were mixed and the mixture was then roasted in a tunnel kiln. The roasted products were treated by two stages of grind- ing followed by magnetic separation. XRD and SEM-EDS examination of the products was used to analyze differences in the roasted products. The results show that coal is one of the most important factors affect- ing the direct reduction roasting process. When the inner coal levels increased from 0% to 15% the iron grade decreased linearly from 94.94%to 88.81% and the iron recovery increased from 55.94% to 92.94%. At the same time the phosphorus content increased from 0.045% to 0.231%. Increasing the inner coal levels also caused more hematite to be reduced to metallic iron but the oolitic structure of the roasted product was preserved in the presence of high coal loading. The phase of the phosphorus in raw ore was not changed after direct reduction roasting. The effect of coal on the phosphorus content in the H-concentrate arises from changes in the difficulty of mechanically liberating the metallic iron from the phosphorus bearing minerals.
