Effect of Cr2O3 addition on corrosion mechanism of refractory castables for waste melting furnaces and concurrent formation of hexavalent chromium
Effect of Cr2O3 addition on corrosion mechanism of refractory castables for waste melting furnaces and concurrent formation of hexavalent chromium
复制标题
Cr2O3添加量对垃圾熔炉用耐火浇注料腐蚀机理及六价铬并发生成的影响
DOI：
10.1016/j.ceramint.2017.10.207
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发表时间：
2018-02-01
影响因子：
5.2
通讯作者：
Xu, Yibiao
中科院分区：
文献类型：
--
作者：
Nath, Mithun;Song, Shengqiang;Xu, Yibiao
含Cr₂O₃的耐火材料被用作各种废弃物熔炉的内衬。尽管其具有令人赞赏的抗腐蚀性能，但六价铬（Cr(VI)）的形成一直是一个主要问题。在还原条件下制备了Al₂O₃ - CaO - Cr₂O₃耐火浇注料（含0、4%、8%和12 wt%的Cr₂O₃）以抑制Cr(VI)的形成，同时在空气气氛中使用废弃物炉渣进行后续腐蚀试验以模拟操作条件。通过XRD和SEM - EDS研究了含Cr₂O₃的刚玉浇注料与合成废弃物炉渣之间的腐蚀机理，而通过浸出试验有效地评估了Cr(VI)的同时形成情况。不含Cr₂O₃的浇注料（0 wt% Cr₂O₃）的腐蚀是通过Al₂O₃和CA(6)相的溶解以及Ca₂(Al,Mg)(Al,Si)₂O₇和(Ca,Na)(Al,Si)₂Si₂O₈的形成发生的，而Al₂O₃ - Cr₂O₃（III）固溶体（含4%、8%和12 wt%的Cr₂O₃）的形成显著限制了这种腐蚀。大多数试样的Cr(VI)含量低于5 mg/L（美国环保局限值）。只有来自炉渣 - 耐火材料界面（C阶段）的试样M3（12 wt% Cr₂O₃）浸出了5.41 mg/L的Cr(VI)，高于美国环保局限值。试样M2（8 wt% Cr₂O₃）在腐蚀和Cr(VI)形成方面表现出最佳性能。
Cr2O3 containing refractories are used as the linings of various waste melting furnaces. Formation of hexavalent chromium (Cr(VI)) has been a major concern despite its admirable corrosion resistance properties. Al2O3-CaO-Cr2O3 refractory castables (0, 4%, 8%, and 12 wt% Cr2O3) were fabricated in reducing condition to inhibit Cr(VI) formation while subsequent corrosion tests using waste slag was performed in air atmosphere to simulate the operating conditions. The corrosion mechanism between Cr2O3-containing corundum castables and synthetic waste slag were investigated by XRD and SEM-EDS, whereas concurrent formations of Cr(VI) were assessed effectively by leaching tests. Corrosion of castables (0 wt% Cr2O3) occurs via dissolution of Al2O3 and CA(6) phases, and formation of Ca-2(Al,Mg)(Al,Si)(2)O-7 and (Ca,Na)(Al,Si)(2)Si2O8, which were significantly restricted by the formation of Al2O3-Cr2O3 (III) solid solution (4%, 8%, and 12 wt% Cr2O3). Most of the specimens exhibited less than 5 mg/L (EPA limit) of Cr(VI). Only specimen M3 (12 wt% Cr2O3) from slag-refractory interface (stage C) leached out 5.41 mg/L of Cr(VI) which is above the EPA limit. Specimen M2 (8 wt% Cr2O3) exhibits optimum properties in terms of corrosion and Cr(VI) formation.