Abstract Stainless-steel pickling sludge (SSPS) is a hazardous solid waste, which mainly contains CaSO4, CaF2 and a high level of metals such as Fe, Cr and Ni. The high-content of sulfur in the SSPS hinders its adequate treatment and deteriorates the quality of hot ferronickel when the SSPS was used as a feed to the rotary kiln-electrical furnace process (RKEF). Thus, the desulfurization behaviors of the SSPS, including thermodynamics, phase transformation and off-gas emission characteristics during pre-reduction were primarily investigated in this work. Pre-reduction temperature and carbon content were essential for the desulfurization, and the reduction temperature should be higher than 850 °C for sufficient sulfur removal. The presence of laterite ore enhanced the desulfurization of SSPS, and on the other hand, the presence of SSPS facilitated the subsequent reduction smelting. Under optimal conditions, almost all of the sulfur within SSPS could be removed by pre-reduction, and 94.72% Fe, 81.90% Ni and 46.14% Cr were recovered by reduction smelting.

中文翻译：

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回转窑-电炉路线协同处理不锈钢酸洗污泥与红土矿：强化脱硫和金属回收

摘要 不锈钢酸洗污泥(SSPS)是一种危险的固体废物，主要含有CaSO4、CaF2和高含量的Fe、Cr、Ni等金属。当 SSPS 用作回转窑 - 电炉工艺 (RKEF) 的进料时，SSPS 中的高硫含量会阻碍其充分处理并降低热镍铁的质量。因此，本文主要研究了 SSPS 的脱硫行为，包括预还原过程中的热力学、相变和废气排放特性。预还原温度和碳含量对脱硫至关重要，还原温度应高于 850°C 才能充分脱硫。红土矿的存在增强了 SSPS 的脱硫作用，另一方面，SSPS 的存在促进了随后的还原冶炼。在最佳条件下，SSPS中的硫几乎可以通过预还原去除，通过还原冶炼回收94.72%的Fe、81.90%的Ni和46.14%的Cr。