LF精炼废渣水热浸出过程中主要矿相的溶解行为

通过水热浸出实验分别研究了精炼废渣及合成的废渣中2种主要单一矿相12CaO?7Al2O3和2CaO?SiO2的溶解行为，并将二者进行对比分析，探究了LF精炼废渣在水热浸出过程中的溶解行为。结果表明，废渣浸出过程中浸出液的pH?12，且随浸出时间增加，电导率和Ca浓度增加，Al浓度急剧下降，Si浓度低于0.1 mg/L且保持不变；12CaO?7Al2O3浸出过程中，随时间增加，浸出液pH值稳定在约11.3，浸出液中Al浓度增加，Ca浓度略微下降。2CaO?SiO2浸出液中主要为Ca2+，Si浓度低于0.6 mg/L；废渣与单一矿相浸出过程的pH值及Al, Si浓度较接近，可以通过单一矿相的溶解行为研究精炼废渣在水热浸出过程中的溶解行为，但废渣浸出液的Al和Si浓度均低于单一矿相，表明废渣中CaO等其它组分溶解抑制了12CaO?7Al2O3和2CaO?SiO2溶解。

Dissolution behavior of main minerals in hydrothermal leaching process of LF refining spent slag

Ladle furnace (LF) refining spent slag is a by-product of molten steel refining process. The reutilization of LF refining slag is rare because of the high content of sulfur in the slag. However, the hydrothermal leaching method can effectively reduce the sulfur content in refining slag and the leached slag has high recycling value. As a composite mineral consisting of a variety of single mineral phases, many components of the refined slag dissolve into the solution during the hydrothermal leaching process, forming a multi-component complex leaching system. It is of great significance to study the dissolution behavior of LF refining slag in hydrothermal leaching process for the recycling of waste residue resources. In order to investigate the dissolution behavior of refining slag, the leaching behavior of LF refining slag and its two main mineral phases (12CaO?7Al2O3 and 2CaO?SiO2) by hydrothermal leaching treatment were studied and the difference between them was compared. The results showed that the pH value of leaching solution was higher than 12 during the leaching process. With the increase of leaching time, both the concentration of Ca and the conductivity of solution increased subsequently, but the concentration of Al decreased sharply. Furthermore, the concentration of Si with a low concentration of less than 0.1 mg/L remained constant. With the increase of time, in the leaching processing of 12CaO?7Al2O3, the pH value of leaching solution was stable with around 11.3, the concentration of Al improved, and the concentration of Ca decreased slightly. Whereas for 2CaO?SiO2, the leaching solution with low concentration of Si (lower than 0.6 mg/L) mainly contained Ca2+. Overall, the pH value and the concentrations of Al and Si of the leaching solution of the slag were close to those of single mineral phase. The dissolution behavior of LF refining slag in hydrothermal leaching process can be studied by the dissolution behavior of single mineral phase. However, the concentration of Al and Si were lower than that of single mineral phase, indicating that the dissolution of 12CaO?7Al2O3 and 2CaO?SiO2 in slag were restricted by the dissolution of CaO and other components.