Steelmaking slag contains considerable quantities of valuable elements such as P and Mn; however, its intrinsic value has not been fully exploited. In steelmaking slag, P is primarily distributed in the 2CaO·SiO₂–3CaO·P₂O₅ solid solution, which can be dissolved readily in the aqueous solution compared with other phases. To separate and recover P from steelmaking slag, selective leaching of the P-containing solid solution was proposed. In this study, sulfuric acid was used as the leaching agent to reduce production costs. The effects of the cooling method of the molten slag, valence of Fe in slag, pH, and particle size on the dissolution characteristic of steelmaking slag were investigated. To achieve an improved selective leaching of P, the molten slag should be oxidized into the Fe₂O₃-containing slag and cooled slowly. As the pH decreased, the dissolution of the slag was promoted, resulting in a higher extraction efficiency of P. The majority of the solid solution was separated without dissolving the Fe-rich magnesioferrite at pH 3, indicating an improved selective leaching of P. Through selective leaching, the P₂O₅ content in the residue decreased significantly. If the formation of CaSO₄ can be suppressed, this residue has the potential to be reused in the steel plant. Decreasing the particle size increased the dissolution rate of slag. A shrinking core model was used to describe the kinetics of slag dissolution. The dissolution of P in the sulfuric acid solution was controlled by diffusion in the residue layer.

中文翻译：

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硫酸溶液中炼钢渣中磷的选择性浸出

炼钢炉渣中含有大量有价值的元素，例如P和Mn。但是，其内在价值尚未得到充分利用。在炼钢渣中，P主要分布在2CaO·SiO ₂ –3CaO·P ₂ O _5中固溶体，与其他相相比，很容易溶于水溶液。为了从炼钢炉渣中分离和回收磷，提出了对含磷固溶体的选择性浸出。在这项研究中，硫酸被用作浸出剂以降低生产成本。研究了熔渣冷却方法，熔渣中铁的价数，pH值和粒径对炼钢熔渣溶解特性的影响。为了改善P的选择性浸出，应将熔融炉渣氧化成Fe ₂ O ₃含渣并缓慢冷却。随着pH值的降低，熔渣的溶解得以促进，从而提高了P的提取效率。分离了大部分固溶体，而在pH 3时不溶解富铁的镁铁素体，表明P的选择性浸出得到了改善。选择性浸出后，残留物中的P ₂ O ₅含量明显降低。如果可以抑制CaSO ₄的形成，则该残留物有可能在炼钢厂中重复使用。减小粒度增加了炉渣的溶解速率。收缩核心模型用于描述熔渣溶解的动力学。通过在残留层中的扩散来控制P在硫酸溶液中的溶解。