钾系添加剂促进磷矿碳热还原的可行性研究

Feasibility Study on Potassium Additive Promoting Carbothermal Reduction of Phosphate Rocks

通过实验模拟电炉法黄磷生产,以磷转化率为指标,研究掺杂钾系物质对磷矿碳热还原的影响。利用热力学分析Ca_3(PO_4)_2分别与无烟煤和石墨的碳热还原反应,结果表明炭活性将影响反应发生的条件;分别添加KCl、K_2CO_3、K_2SO_4、KOH,通过改变温度、反应时间、添加量,考察得到磷转化率与三因素的关系为正相关,其中K_2SO_4促进效果较好;最佳工艺条件分别为碳过量系数δ=1. 5,酸度值M=0. 71,温度T=1400℃,反应时间120 min,K_2SO_4添加量为3. 0%,此时磷转化率达93. 43%;由化学反应动力学分析得,添加K_2SO_4反应体系活化能为123. 94 kJ·mol^(-1),无添加体系为162. 38 k J·mol^(-1),反应活化能显著降低。

By means of simulating yellow phosphorus production process in an electric furnace,an experiment was conducted to study the influence of potassium compounds on the carbothermic reaction of phosphate rock.Thermodynamics was used to analyze the carbothermic reactions between Ca3(PO4)2 and anthracite and graphite respectively,the result of which indicated that the activeness of carbon would affect reaction conditions;by respectively adding KCl,K2CO3,K2SO4,and KOH into the reaction and adjusting reaction temperature,reaction time and additive amount,the conversion ratio of phosphorus was found to be positively related to the three factors and K2SO4 was found to have the best promotion effect;the optimal process condition was that 1.5 excessive carbon coefficient(δ),0.71 pH value(M),1400℃(T),120 min reaction time,and 3.0% additive amount of K2SO4.In this condition,the conversion ratio of phosphorus reached 93.43%.Analyzing by chemical reaction kinetics,it was found that activation energy of the reaction system was 123.94 kJ·mol^-1 with the presence of K2SO4 and was 162.38 kJ·mol^-1 without,which showed a significant decrease in activation energy.