碱度对转炉渣中磷富集的影响

Effect of basicity on the enrichment of phosphorus in BOF slag

基于离子和分子共存理论,通过理论计算与试验研究了1673 K时转炉渣中磷的富集能力。研究结果表明:转炉渣中形成的复杂分子主要为2FeO·SiO_(2)、CaO·SiO_(2)、2CaO·SiO_(2)(C2S)以及3CaO·SiO_(2)四种硅酸盐复杂分子和3FeO·P_(2)O_(5)、4FeO·P_(2)O_(5)、2CaO·P_(2)O_(5)、3CaO·P_(2)O_(5)(C3P)以及4CaO·P_(2)O_(5)五种磷酸盐分子,其中C2S的质量作用浓度显著高于另外三种硅酸盐,C3P的质量作用浓度的数量级显著高于另外四种磷酸盐,其分别在碱度为1.8和1.7时达到峰值;磷主要富集于C_(2)S-C_(3)P固溶体中,随着碱度的增加,磷富集可能性(NC_(2)S-C_(3)P)先逐渐增大,在碱度为1.75时达到峰值,随后逐渐降低;磷富集程度(RC_(2)S-C_(3)P)与分配比(LPs/l)与碱度的变化趋势一致,RC_(2)S-C_(3)P和LPs/l分别在碱度为2.2和1.9时达到峰值,分别为87.1%和11.4;工业试验显示炉渣的脱磷能力在碱度约为1.8时达到最大。

The enrichment capacity of phosphorus in BOF slag at 1673 K was studied by theoretical calculation and experiment based on an ion and molecule coexistence theory.The results showed that there were four kinds of silicate complex molecules(2FeO·SiO_(2),CaO·SiO_(2),2CaO·SiO_(2)(C2S)and3CaO·SiO_(2))and five kinds of phosphates(3FeO·P_(2)O_(5),4FeO·P_(2)O_(5),2CaO·P_(2)O_(5),3CaO·P_(2)O_(5)(C3P)and 4CaO·P_(2)O_(5))in BOF system slag.The mass action concentration of C2S was significantly higher than that of the other three silicates and the mass action concentration of C3P was dramatically higher than that of the other four phosphates,they reached the peak when the basicity of slag were about1.8 and 1.7 respectively.Phosphorus was mainly enriched in C_(2)S-C_(3)P solid solution.With the increase of basicity,the possibility of phosphorus enrichment,NC2C-C3P,increased gradually first and reached the peak at basicity of 1.75,then decreased gradually.The change of phosphorus enrichment degree(RC_(2)S-C_(3)P)and phosphorus distribution ratio(LPs/l)with basicity was consistent,the maximum value of RC_(2)S-C_(3)Pand LPs/lwere 87.1%and 11.4 when R were 2.2 and 1.9 respectively.The industrial test showed that the dephosphorization capacity of slag reached the maximum when R was about 1.8.