Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher ...Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher pre- heating temperature and longer preheating time than that of single magnetite concentrate. Therefore, it is difficult for preheated pellets to withstand the mechanical collision in the roasting process in rotary kiln. It was found that after the iron concentrate being subjected to high pressure roll grinding, the specific surface area reached 2 029. i cm2/g. Consequently, the preheating and roasting temperature of pellets were decreased by 70 and 50 ℃ and preheating and roasting time were decreased by 2 and 4 min, respectively. Meanwhile, the compression strength of preheated and roasted pellets were increased by 200 N for a pellet and 220 N for a pellet, respectively. The mechanism lied in that the increase of specific surface area activated thermal reaction and promoted formation of inter-grain bridge.展开更多
基金Item Sponsored by National Natural Science Foundation of China(50725416)
文摘Investigation was conducted on roasting properties of pellets with an iron concentrate of complex mineral composition. The results indicated that the pellets of complex mineral composition concentrate required higher pre- heating temperature and longer preheating time than that of single magnetite concentrate. Therefore, it is difficult for preheated pellets to withstand the mechanical collision in the roasting process in rotary kiln. It was found that after the iron concentrate being subjected to high pressure roll grinding, the specific surface area reached 2 029. i cm2/g. Consequently, the preheating and roasting temperature of pellets were decreased by 70 and 50 ℃ and preheating and roasting time were decreased by 2 and 4 min, respectively. Meanwhile, the compression strength of preheated and roasted pellets were increased by 200 N for a pellet and 220 N for a pellet, respectively. The mechanism lied in that the increase of specific surface area activated thermal reaction and promoted formation of inter-grain bridge.
