Experimental studies on solid‐state reduction of pickling sludge generated in the stainless steel production
Experimental studies on solid‐state reduction of pickling sludge generated in the stainless steel production
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DOI：
10.1111/j.1600-0692.2005.00717.x
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发表时间：
2005-02
期刊：
影响因子：
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通讯作者：
Ping Ma;B. Lindblom;B. Björkman
中科院分区：
文献类型：
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作者：
Ping Ma;B. Lindblom;B. Björkman
不锈钢生产过程中产生的中和酸洗污泥含有大量的氟化钙、水和相对较低的金属含量，这使得难以直接回收回炼钢过程。如果长期存放在室外，也会造成潜在的环境问题。然而，金属如铁、镍和铬，以氧化物和/或氢氧化物的形式，以及污泥中的氟化钙，对不锈钢制造商来说是经济上的问题。因此，为了开发经济和技术上合适的回收工艺，分别使用石油焦（P-coke）和石墨作为还原剂，在高达1400°C的温度下使用热重（TG）分析进行了还原酸洗污泥和金属氧化物混合物的比较研究。同时，在塔曼炉上，在800-1200°C温度范围内，进行了磷焦还原酸洗污泥的实验室试验。热重分析的对比研究结果表明，酸洗污泥的还原行为可以通过与酸洗污泥中具有相同组成的金属氧化物混合物的还原行为来接近。塔曼炉试验结果表明，温度对还原有显著影响。还原产物中被还原的金属主要以“（Fe，Ni）”和“Cr-Fe-Ni”等合金形式存在。
Neutralized pickling sludge generated during stainless steel production contains large amounts of calcium fluoride, water and a relatively low metal content, which makes it difficult to directly recycle back to the steelmaking process. It would also pose a potential environmental problem if deposited outdoors over a long term. However, metals such as iron, nickel and chromium, in the form of oxides and/or hydroxides, as well as calcium fluoride in the sludge, are of economic concern to stainless steel makers. Therefore, to develop an economically and technically suitable recycling process, a comparison study on reducing both pickling sludge and mixtures of metal oxides, using petroleum coke (P-coke) and graphite as reductant, respectively, was carried out at temperatures up to 1400°C using thermogravimetric (TG) analysis. Meanwhile, laboratory-scale tests on reducing pickling sludge, using P-coke as reductant, were also conducted in a Tammann furnace at 800–1200°C. Results of the comparison study by TG demonstrate that the reduction behaviour of pickling sludge may be approached by the reduction behaviour of the metal oxide mixture having the same composition as those in the pickling sludge. Results of the Tammann furnace tests show that temperature has a significant influence on reduction. The reduced metals in the reduction products exist mostly in the form of alloys such as ‘(Fe,Ni)’ and ‘Cr–Fe–Ni’.