Stainless steel pickling sludge is the precipitate from the neutralization process of stainless steel pickling liquor. Until now, many methods about the harmless treatments of pickling sludge have been developed, and among them the most effective one is to produce Fe-Cr-Ni alloy by carbothermic reduction process. However, the carbon and sulfur (harmful elements for steel) contents of the produced Fe-Cr-Ni alloy are difficult to be controlled, especially for the high-CaSO4 sludge. The current paper proposed a new method to produce the low-carbon and low-sulfur Fe-Cr-Ni-Si alloy by using the high-CaSO4 stainless steel pickling sludge. Firstly, the sludge was pre-reduced by carbon at 1100 °C. Then, the pre-reduced sludge was mixed with silicon powder and reacted at 1550 °C for the deep reduction, separation, and desulfurization. By the current method, the Fe-Cr-Ni-Si alloy with a carbon content of 0.513 wt pct and a sulfur content of 0.003 wt pct was produced. Meanwhile, the Fe, Cr, and Ni contents in alloys were 59.600, 15.440, and 13.570 wt pct, with recovery rates of 97.99, 97.61, and 98.65 pct, respectively. Such an alloy can be used as the alloy additive for stainless steel production.

中文翻译：

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含CaSO4不锈钢酸洗液制备低碳低硫Fe-Cr-Ni-Si合金

不锈钢酸洗污泥是不锈钢酸洗液中和过程中产生的沉淀物。迄今为止，已开发出多种酸洗污泥无害化处理方法，其中最有效的方法是碳热还原法生产Fe-Cr-Ni合金。然而，所生产的Fe-Cr-Ni合金的碳和硫（对钢有害的元素）含量难以控制，特别是对于高CaSO4污泥。本文提出了一种利用高CaSO4不锈钢酸洗污泥生产低碳低硫Fe-Cr-Ni-Si合金的新方法。首先，污泥在1100℃下用碳预还原。然后将预还原污泥与硅粉混合，在1550℃反应进行深度还原、分离和脱硫。按照目前的方法，生产了碳含量为 0.513 wt pct 和硫含量为 0.003 wt pct 的 Fe-Cr-Ni-Si 合金。同时，合金中的 Fe、Cr 和 Ni 含量分别为 59.600、15.440 和 13.570 wt pct，回收率分别为 97.99、97.61 和 98.65 pct。这种合金可用作不锈钢生产的合金添加剂。