碱度对精炼渣理化性能及磷元素迁移的影响

Effect of basicity on physicochemical properties and phosphorus migration of refined slag

外加电场处理冶金废渣中磷杂质是冶金固废循环利用的重要方式之一。为探究熔渣理化性能对电场强化冶金渣磷元素分离的影响,综合红外光谱、旋转黏度计法、四探针法以及脉冲电场试验,获得不同碱度条件下CaO-SiO_(2)-Al_(2)O_(3)-MgO精炼渣系的结构特征、黏度、电导率,并分析精炼渣理化性能对电场作用下磷迁移效率的影响。结果表明,渣系碱度在2.3~3.2内增加,Si-O和Al-O网络结构呈现解聚-聚合-解聚作用;综合熔渣熔化温度及网络结构影响,熔渣黏度呈现出降低-升高-降低趋势,而综合熔渣阳离子浓度及网络结构影响,熔渣电导率变化趋势与黏度相反;无电场时,综合熔渣网络结构和黏度影响,渣中磷元素迁移率呈现增大-降低-增大趋势,施加电场后,渣钢间原本的平衡态受到破坏,由于熔渣电导率和黏度及网络结构叠加作用,促进了磷元素的进一步迁移,且磷迁移率随碱度增加的变化规律与无电场时呈现的规律一致。

The treatment of phosphorus impurity in metallurgical waste residue by applied electric field is one of the important ways of metallurgical solid waste recycling.In order to explore the influence of physical and chemical properties of molten slag on the phosphorus separation of metallurgical slag enhanced by electric field,the structural characteristics,viscosity and conductivity of CaO-SiO_(2)-Al_(2)O_(3)-MgO refining slag system under different basicity conditions were obtained by combining infrared spectroscopy,rotary viscometer method,four-probe method and pulsed electric field experiment.The effect of physicochemical properties of the refining slag on phosphorus transport efficiency under electric field was also analyzed.The results showed that the slag basicity increased in the range of 2.3-3.2,Si-O and Al-O network structure presented the trand of depolymerization-polymerization-depolymerization.Combined with the influence of slag melting temperature and network structure,the slag viscosity showed a decreasing-increasing-decreasing trend,while combined with the influence of cation concentration and network structure,the change trend of slag conductivity was opposite to that of viscosity.In the absence of electric field,due to the influence of slag network structure and viscosity,the mobility of phosphorus in slag showed an increase-reduce-increase trend.After the application of electric field,the original equilibrium state between slag and gold was destroyed.Due to the superposition of slag conductivity,viscosity and network structure,the further migration of phosphorus was promoted,and the variation of phosphorus mobility with the increase of basicity was consistent with that without electric field.