Al2 O3对连铸保护渣中氟浸出的影响

为了消除保护渣在使用过程中氟溶解到水中造成的危害,提出了开发高Al2 O3含量的保护渣.研究了不同含量的Al2 O3对保护渣熔渣水浸液中F-质量浓度和pH值的影响,并利用X射线光电子能谱分析了Al2 O3含量对保护渣熔渣结构的影响.当Al2 O3的质量分数为4%时,保护渣迁移到水中的F-质量浓度为22.8~35.4 mg·L-1,pH值的变化范围为4.0~9.5；当Al2 O3的质量分数由4%增加到34%,F-质量浓度和pH值的变化范围均是先急剧减小后略有增加的趋势. X射线光电子能谱分析显示：增加保护渣中Al2 O3的含量时,保护渣中Al2 O3通过形成Al—F共价键,抑制了氟的浸出.控制保护渣中Al2 O3的质量分数在16%~34%的范围,则实验水样中F-质量浓度在4.0~10.0 mg·L-1的范围,pH值在6.5~7.5的近中性范围,可减弱氟浸出造成的危害.

Effects of Al2 O3 on the leaching of fluorine in mold fluxes

In order to eliminate the hazard effects of the leaching of fluorine in mold fluxes, this paper introduces a mold flux with high Al2 O3 content. The effects of Al2 O3 content on the concentration of F- ions and the pH value of leaching water were investigated, and the dependence of Al2 O3 on the structure of mold fluxes was analyzed by X-ray photoelectron spectroscopy ( XPS) . When the mass fraction of Al2 O3 is 4%, the concentration of F- ions in leaching water is about 22. 8 to 35. 4 mg·L-1 , and the pH range is between 4. 0 and 9. 5. The F- concentration and the pH range initially reduces and then slightly rises again as the Al2 O3 content increases from 4% to 34%. The XPS spectra show that the Al-F bond forms in the mold flux when the Al2 O3 content increases. This can restrain the dissolution of fluorine in water. Controlling the content of Al2 O3 between 16% and 34%, the F- concentration in leaching water is about 4. 0 to 10. 0 mg·L-1 , and the pH range is between 6. 5 and 7. 5. This is helpful to reduce the hazard effects of the leaching of fluorine in mold fluxes.