Abstract

Phosphorus recovery from dephosphorization slag generated during steelmaking has enormous potential to secure a stable supply of phosphate. Because P and Fe in slag are concentrated in different mineral phases, P can be recovered by separation of the P-bearing phase, and the residue can be reutilized in steel plant at the same time. In the present study, we adopted selective leaching of P and investigated the effects of leaching parameters on the dissolution behavior of slag. It was determined that with the decrease in particle size and increase in stirring speed, the P dissolution ratio increased significantly. When particle size was less than 53 μm and stirring speed exceeded 200 rpm, most of the P-bearing C₂S−C₃P solid solution was dissolved and separated. Increasing temperature and decreasing the mass ratio of slag to liquid had a slight influence on promoting P dissolution, while the Si dissolution was significantly suppressed in the case of high temperature and mass ratio due to the formation of silica gel. The P dissolution ratio reached 84.9%, and the Fe dissolution was negligible. Through selective leaching, the residue primarily consisting of magnesioferrite could be used as a flux in steelmaking process. The shrinking core model was successfully used to describe the dissolution kinetics of P. As temperature increased, apparent rate constant increased slightly. The calculated activation energy was 9.23 kJ/mol, demonstrating that the P dissolution was controlled by diffusion in the residue layer.

Graphical Abstract

Most of the P-bearing solid solution in dephosphorization slag was dissolved and the dissolution of Fe-bearing phase was negligible, achieving selective leaching of P. The P dissolution from slag was controlled by diffusion in the residue layer.

中文翻译：

---

脱磷渣中磷选择性浸出的动力学研究

摘要

从炼钢过程中产生的脱磷炉渣中回收磷具有确保稳定供应磷的巨大潜力。由于炉渣中的P和Fe集中在不同的矿物相中，因此可以通过分离P轴承相来回收P，并将残渣同时在钢铁厂中再利用。在本研究中，我们采用了P的选择性浸出，并研究了浸出参数对炉渣溶解行为的影响。可以确定，随着粒径的减小和搅拌速度的增加，P的溶出率显着增加。当粒径小于53μm且搅拌速度超过200 rpm时，大多数含P的C ₂ S-C ₃将P固溶体溶解并分离。升高温度和降低炉渣与液体的质量比对促进P的溶出有轻微的影响，而在高温和质量比的情况下，由于硅胶的形成，Si的溶出被显着抑制。P的溶解度达到84.9％，Fe的溶解度可以忽略不计。通过选择性浸出，主要由菱铁矿组成的残渣可用作炼钢过程中的助熔剂。收缩核模型已成功用于描述P的溶解动力学。随着温度的升高，表观速率常数略有增加。计算出的活化能为9.23 kJ / mol，表明P溶解是通过在残留层中的扩散来控制的。

图形概要

脱磷炉渣中的大多数含磷固溶体均被溶解，而含铁相的溶质可忽略不计，从而实现了对磷的选择性浸出。熔渣中磷的扩散受残渣层中扩散的控制。