材料期刊网

利用空气顶吹研究熔渣的气态脫硫动力学,着重研究了熔渣∑FeO含量、j值[j=N_(Fe_2O_3)/(N_(Fe_2O_3)+N_(FeO))]、以及碱度对气态脫硫速度的影响.对气态脫硫反应的机理及反应速度的限制性环节作了分析和讨论.最后,对金属直接的气态脫硫、炉渣的气态脫硫和炉渣脫硫本身的矛盾、以及气态脫碗在转炉炼钢工艺上的应用问题进行了简要的讨论.

The desulphurization of molten slags in the gaseous phase during top-blown with air has been studied from the kinetic standpoint, emphasis being made to study the effects of FeO, the j value (j=N_(Fe_2O_(3))/(N_(Fe_2O_3)+N_(FeO))) and the basicity of the slag upon the rate of removal of sulphur. It has been found that this gaseous desulphurization takes place according to the following reaction: (S~(2-))+3/2O_2=SO_2+(O~(2-)), (1)while the iron ions in the slag serve only as the oxygen-carriers:6(Fe~(3+))+(S~(2-))+2(O~(2-))=6(Fe~(2+))+SO_2, (2)6(Fe~(2+))+3/2O_2=6(Fe~(3+))+3(O~(2-)). (3)With slags containing very little or no FeO or slags with constant j value, as when air is blown upon the slag surface from a rather remote distance, the reaction has been found to be of the first order, the transfer of S~(2-) ions inside the slag being most probably ratecontrolling. An increase in the FeO content and the j value of the slag, as well as the temperature, accelerates the speed of removal of sulphur, while an increase in slag basicity retards it. It has been proposed that, owing to the oxidizing character of the blown-in air, SO_4~(2-) ions might have been formed inside the slag, but at the high temperatures prevailing, they decompose immediately into SO_2 and O_2. Any sulphate that may be present in the solidified slag is most probably being formed on its way of cooling in air. Attention has been called to resort to the correct method of analysis of total sulphur in the slag, the combustion method using CO_2 as the oxidizer being more accurate than the method using pure O_2. It has also been shown experimentally that the direct gaseous desulphurization of the metal is not so feasible as that of the slag, and that there exists some contradiction between the desulphurization of the metal with slag and the gaseous desulphurization of the slag. With a view to bringing about as a whole a more efficient desulphurization, the possibility of adapting the gaseous desulphurization to the actual steelmaking practice with the converter is briefly discussed.