Xia Ming, Su Pengyue, Wang Hao, Lu Huicheng, Chen Haiyu, Zhao Shujie, Li Dongwei
School of Environmental and Chemical Engineering, Jiangsu Ocean University Lianyungang 222005 China
Jiangsu Institute of Marine Resources Development, Jiangsu Ocean University Lianyungang 222005 China.
RSC Adv. 2024 Jan 3;14(2):1377-1385. doi: 10.1039/d3ra06820j. eCollection 2024 Jan 2.
Chromite ore processing residue (COPR) is a hazardous waste because of leachable chromium, especially Cr(vi). Therefore, ascorbic acid (AA) and blast furnace slag (BFS) have been used to detoxify and solidify COPR. On this basis, environmental stability experiments with high temperature and freeze-thaw cycles were carried out to explore the stability performance of a solidified body with 40% COPR. The environmental stability performance was analyzed through changes in edge length, mass loss, compressive strength development, and leaching concentration of Cr(vi). The result indicated that the high-temperature environment had much more effect on the solidified body than the freeze-thaw cycle environment in these four aspects: after being maintained at 900 °C for 2 h, the compressive strength of the solidified bodies reached its minimum value (35.76 MPa). However, in the freeze-thaw cycle experiments, the compressive strength of the solidified bodies consistently remained above 80 MPa, and the leaching of hexavalent chromium was below the limit (5 mg L). In addition, X-ray diffraction (XRD) and Fourier transform infrared spectrometry (FTIR) analysis verified that COPR was effectively solidified through physical and chemical means. Moreover, high temperature changes the molecular structure of the solidified body, thus reducing the compressive strength and curing ability of the solidified body, while the freeze-thaw cycle experiment has little effect on it.
铬铁矿选矿残渣（COPR）由于含有可浸出的铬，尤其是六价铬，所以是一种危险废物。因此，已使用抗坏血酸（AA）和高炉矿渣（BFS）对COPR进行解毒和固化。在此基础上，进行了高温和冻融循环的环境稳定性实验，以探究含40% COPR的固化体的稳定性性能。通过边长变化、质量损失、抗压强度发展以及六价铬的浸出浓度来分析环境稳定性性能。结果表明，在这四个方面，高温环境对固化体的影响远大于冻融循环环境：在900℃下保持2小时后，固化体的抗压强度达到最小值（35.76MPa）。然而，在冻融循环实验中，固化体的抗压强度始终保持在80MPa以上，并且六价铬的浸出量低于限值（5mg/L）。此外，X射线衍射（XRD）和傅里叶变换红外光谱（FTIR）分析证实，COPR通过物理和化学手段得到了有效固化。而且，高温改变了固化体的分子结构，从而降低了固化体的抗压强度和固化能力，而冻融循环实验对其影响较小。
