EAF slag constitutes a major waste in the steel industry, which necessitates the development of processes to recover its valuable compounds and thermal energy values. A promising method involves the modification of the composition of EAF slag melts to utilize its waste heat and recover more valuable elements by controlled crystallization of spinel under a cooling process. In this study, crystallization behaviors of modified EAF slag melts with a basicity of 1.2 were investigated, with the aim of precipitating more magnetic spinel phases, and leaving a matrix with the amorphous phase, which favors subsequent utilization in the cement industry. Samples were prepared at different cooling temperatures, for different holding times, or quenched by air or water. Results show that two kinds of spinel phases were found during the cooling process of the melts. One was bulky spinel (BS) in granular form with size > 40 μ m, and the other was dendritic spinel (DS) with arms < 20 μ m. Three stages existed in the crystallization process of the melts. It is crucial to keep the slag melts in stage one for less than 30 minutes and then rapidly cool it to stage three. More and larger BS was obtained when this method was applied.

中文翻译：

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改性电弧炉渣冷却过程中尖晶石的结晶行为

EAF 炉渣是钢铁行业的主要废物，因此需要开发工艺以回收其有价值的化合物和热能价值。一种有前景的方法涉及改变 EAF 熔渣熔体的成分，以利用其废热并通过在冷却过程中控制尖晶石结晶来回收更多有价值的元素。在这项研究中，研究了碱度为 1.2 的改性电弧炉渣熔体的结晶行为，目的是沉淀更多的磁性尖晶石相，并留下具有非晶相的基体，有利于后续在水泥工业中的应用。样品在不同的冷却温度、不同的保温时间下制备，或者用空气或水淬火。结果表明，在熔体冷却过程中发现了两种尖晶石相。一种是粒径 > 40 μ m 的颗粒状大尖晶石 (BS)，另一种是臂 < 20 μ m 的树枝状尖晶石 (DS)。熔体的结晶过程存在三个阶段。将第一阶段的炉渣熔化时间保持在 30 分钟以内，然后迅速冷却至第三阶段，这一点至关重要。当应用这种方法时，获得了越来越大的 BS。