| In this paper,the compared experiment of desulphurization of hot metal of Chongqing Iron and Steel Co.(in short CQ),which is used by different desulphurizing agents,has been carried out in lab. On the base of the experiment,it is selected three type desulphurizing agents that fit the production condition of CQ have been carried out for industrial experiment,which are CaO-based,CaO-AD-based and CaO-Mg-based synthetic desulphurizing agent. It provided an economical and practical scheme of desulphurizing agent for product line. Meanwhile,the injection technologic parameters have been optimized,and a forecast model of consuming desulphurizing agent has been developed. The smelting resulfurization and smelting low-surphur steel in jar and converter after hot metal desulphurization have been researched. Finally,desulphurization capacity and entire consuming of Mg and CaO-based desulphurizing agent mixed insufflating have been on ampliative and industrial research. Then the conclusions can be drawn as following:(1)Through the experiments in lab and the thermodynamics analysis of the three types desulphurizing agents,which are CaO-based,CaO-AD-based and CaO-Mg-based desulphurizing agent,it can be gained that the array order of the desulphurization capacity from the stronger to the weaker is:CaO-Mg-based-CaO-AD-based - CaO-based.(2)The type of desulphurizing agent fit the production condition of CQ has been confirmed though the industrial experiment. Medium desulphurizing agent is CaO-based and deep desulphurizing agent is Mg plus CaO-based.(3)Aiming at the actual problem in desulfurization process of CQ,the desulphurization technologic parameters have been optimized on the basis of confirming the scheme. It is obtained approving metallurgical effect. Disposal cost has declined 5.991 yuan per ton steel,and the economic and social benefit is obvious.(4) With the foundation of consuming desulphurizing agent model,by using CaO -based desulphurizing agent,target sulfur is in the range of 0.006-0.010,and consuming fractional error has not been exceeded 5%. The unreasoning disadvantage of charging before having the model has been overcame. It is important for increasing the desulphurization rate and declining the production cost.(5) The control factors resulfurized of the desulphurizing hot metal in ladle have three important aspects:the structure of lance,the process after disturbing and the waiting time of hot metal. Through orthogonal experiment method,it can be obtained that the scrap quality is the chiefly factor to affect resulfurized of the desulphurizing hot metal in the converter at the steelworks in CQ:The second factor is decided by the slag removal which is better or not;The last factor is decided by lime quality. The best production scheme of low-sulfur steel,which can ensure lowest the resulfurization quantity,is:the high quality of slag removal,low-sulfur scrap,low-sulfur lime burnt by gas.(6)The low-sulfur steel experiments can prove that the steelworks in CQ has the capacity of producing the low-sulfur steel for the sulfur content less than 0.015% of the finished products by using the technical process of "desulfurization hot metal with CaO-based,converter smelting,argon-bubbling treatment and continuous casting. "(7)The experiment of insufflating Mg and CaO-based desulphurizing agent had been carried out. It can be obtained that the final point [S] could achieve 0.006-0.010%. Comparing the CaO-based desulphurizing agent,the consumed amount of powder reagent could be decreased 2 Kg per ton,the disposal time could be saved 3 minutes,and the reduced temperature could be decreased more than 17 C. The shortage of the experiment is Mg in the desulphurizing agent has great segregation,and it iscorrespondingly difficult for separating slag from hot metal.
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