铁水同时脱磷脱硫的最佳氧位与电位

Optimum Oxygen Potential and Electrode Potential of Simultaneous Dephosphorization and Desulfurization in Hot Metal Pretreatment

利用ZrO_2·MgO固体电解质定氧探头测定了实验1kg级铁水喷吹CaO系熔剂同时脱磷脱硫处理过程中反应初始和终了的铁水氧位,并进行了热力学分析。测定的初始氧位范围为Po_2=10^(-8)·45～10^(-9)·75Pa(10^(-13)·46～10^(-14)·70atm),比按C/O、Si/O平衡反应计算的氧位提高1～3个数量级,测定的终了氧位范围为Po_2=10^(-7)～10^(-9)Pa(10^(-12)～10^(-14)atm),比初始氧位提高1～3个数量级,与热力学计算的最佳氧位值(Po_2=10^(-7.88)·Pa(10^(-12.88)·atm))吻合良好。结果表明,随铁水终了氧位升高,脱磷率增加、终了磷含量下降,脱硫率则稍有降低、终了硫含量稍微升高。此外,还从电化学上对同时脱磷脱硫处理的最佳氧位—电位区域进行了分析,并探讨了铁水罐喷吹脱磷脱硫处理的反应机理。

Initial and final oxygen potential in simultaneous dephosphori-zation and desulfurization pretreatment with injection of CaO-based fluxes were measured by using of the oxygen sensors of ZrO2·MgO solid electrolyte in our laboratory and the thermodynamic analysis were considered. The results shown that: (1) initial oxygen potential is Po2 = 10-8·45 - 10-9·7 Pa (10-13·46-10-14·76 atm) which is 10-103 times as high as the oxygen potential calculated from the C/O or Si/O equilibrium reaction. (2) final oxygen potential is Po2 = 10-7-10-9 Pa (10-12-10-14 atm) which is 10-103 times as high as the initial oxygen potenlip.l and is in good agreement with the optimum oxygen potential in the thermodynamic calculation (Po2 = 10-7·88 Pa (10-12·88 atm). And (3) dcphosphorization ratio increases, final phosphorus content decreases, and dcsulfurization ratio decreases slightly, final sulfur content increases slightly with increasing of oxygen potential in hot metal.In addition, optimum oxygen-electrode potential range were analyzed in electrochemistry, and the reaction mechanism of simultaneous dephosphorization and desulfurization in injection pretroatmcnt within hot metal ladle was also discussed.