钢渣中磷在盐酸中的浸出动力学研究

Study on Kinetics of Dephosphorization Process of Steel Slag

磷是农作物生长不可缺少的营养元素,其储备有限,从钢渣中回收磷元素被认为是一种有效的解决办法。为了保证磷的可持续供应,提高钢渣中磷的浸出率,降低无机酸浸出液的用量,本文进行了低浓度盐酸溶液钢渣浸磷动力学研究,分析了酸浓度、反应温度、时间、搅拌速率、液固比及钢渣粒度等因素对磷浸出率的影响规律,确定了磷浸出过程的限制性环节,并建立了浸出动力学模型。研究结果表明:磷在最佳浸出条件下的浸出率为99.78%,磷的浸出过程符合未反应核收缩模型,固体层的扩散是限制性环节,浸出反应的活化能为9.81 kJ/mol,浸出动力学方程为1-3(1-x)^((2/3))+2(1-x)=0.3185(C)^(1.98)·(PS)^((-1.92))·(SS)^(0.78)·(LS)^(1.68)exp(-9.81/RT)。

Phosphorus is an indispensable nutrient element for crop growth,while its reserves are limited.It is considered an effective solution to recover phosphorus from steel slag.To ensure the sustainable supply of phosphorus,to improve the leaching rate of phosphorus in steel slag and to reduce the amount of inorganic acid leaching solution,the kinetics of phosphorus leaching from steel slag with low concentration hydrochloric acid solution was studied in this paper.The effects of acid concentration,reaction temperature,time,stirring rate,liquid-solid ratio and steel slag particle size on the phosphorus leaching rate were analyzed,the limiting links in the phosphorus leaching process were determined,and the leaching kinetics model was established.The results show that the leaching rate of phosphorus under the optimal leaching conditions is 99.78%,the leaching process of phosphorus conforms to the unreacted nuclear shrinkage model,the diffusion of solid layer is the limiting link,the activation energy of leaching reaction is 9.81kJ/mol,and the leaching kinetic equation is 1-3(1-x)^((2/3))+2(1-x)=0.3185(C)^(1.98)·(PS)^((-1.92))·(SS)^(0.78)·(LS)^(1.68) exp(-9.81/RT).