The Processing Technology On Hot Stuffy And Application In Building Materials Of Steel Slag

Nowadays,the comprehensive utilization rate of steel slag which was discharged by steel enterprises in china was about 20%,and most of them belonging to the pattern with low value.This kind of way not only wasted resource,but also resulted in environmental pollution.Aparting from the influences of several factors,such as large fluctuations in composition,poor stability,low activity and bad grind-ability,the key problem of steel slag was not handled effectively in long time was that technical difficulties of steel slag pretreatment.The research and application on using steel slag power to replace cement partly or concrete were less.Basing on the systematic review of the comprehensive utilization of metallurgical slag at home and abroad,this dissertation analysis the main factors of influencing how to use steel slag with high value,optimizing hot stuffy and self degradation technology control parameters under 1650 centigrade through the industrial test when facing the bottleneck problem.Besides,it also discussed the feasibility of using composite powder to product high performance concrete by the experiment of mortar test and concrete test.The industrial test results show that the optimal process control parameters of the product line of steel slag with the conditions of hot stuffy and self degradation as follow:700⁸00 centigrade of inlet temperature of steel slag,grain size greater than300mm is not greater than 20%,hot stuffy pressure was controlled between 0.4⁰.7MPa,90min of hot stuffy time,continuous water spray.The steel slag was handled according to the above conditions will get the highest powder rate and best stability.The experiment results of steel slag and mineral slag show that the activity of steel slag obviously was lower than that of mineral slag at the same fineness,30%⁴0%steel slag in composite powder would be the most economic program,the optimal condition as follow:specific surface of steel slag 400?/kg,specific surface of mineral slag 410?/kg,the composite ratio of steel slag50%.Besides,the dosage of composite powder could not be more than 30%when we produce different intensity concrete excepting for C30.500?/kg steel slag account for half of the powder or one third of all,the efficiency of composite powder will be strengthen.we analysised the mechanism of steel slag powder for concrete from the concrete hydration products,pore structure and the synergy of steel slag powder and slag powder.the result show that steel slag powder have the functions of filling,and weakening the effect of early performance of concrete in the early hydration.Ca?OH?₂ produced at the process of steel slag hydration could improve the activity of steel slag,meanwhile,the consumption of Ca?OH?₂ caused by slag powder have positive effect on promoting the further digestion of f-CaO of steel slag.More appropriate grading between steel slag powder and slag powder can enhance the working performance of concrete.