钢渣吸附除磷机理研究

MECHANISM OF PHOSPHORUS ADSORPTION FROM AQUEOUS SOLUTION ON STEEL CONVERTER SLAGS

研究了氨离子和几种阴离子对钢渣吸附除磷效果的影响,探讨了钢渣吸附除磷的机理。结果表明,氨离子、氯离子和硝酸根离子对钢渣吸附除磷基本没有影响,而碳酸根和硫酸根使除磷效果显著降低,这是因为混合溶液中碳酸根、硫酸根和磷酸根之间互相竞争,争夺钢渣中的钙离子。进一步研究表明,饱和钢渣中Ca、Mg-P的质量分数为总磷的80%以上,而Ca-P是Ca、Mg-P的主要成分,因此,钢渣吸附除磷的主要机理是钢渣中溶出的钙离子与磷酸根离子结合形成沉淀。

This phosphorus adsorption mechanism was examined and effect ofNH4^＋-N, HCO3^-, NO3^-, SO4^2- and Cl^- was investigated. Results showed that the effect of NH4^＋-N, Cl^- and NO3 on phosphorus adsorption is insignificant. HCO3 and SO4^2- significantly decrease the phosphorus adsorption capacity because the competition among HCO3^-, SO4^2- and PO4^3- for Ca^2＋ is occurred in complex solutions. Various P forms in saturated steel converter slags were fractionated. Results showed that concentration of Ca, Mg-P is above 80% ofTP. Ca-P is the majority in the Ca,Mg-P. Accordingly, the precipitation reaction with element of calcium in steel converter slags was the dominating mechanism of phosphorus adsorption.