Li Junguo, Liu Bao, Zeng Yanan, Wang Ziming, Gao Zhiyuan
College of Metallurgy and Energy, North China University of Science and Technology, Tangshan, 063009, People's Republic of China.
Environ Monit Assess. 2017 Mar;189(3):113. doi: 10.1007/s10661-017-5843-4. Epub 2017 Feb 16.
AOD (argon oxygen decarburization) slag is the by-product in the stainless steel refining process. Chromium existing in AOD slag can leach out and probably poses a serious threat to the environment. To assess the leaching toxicity of chromium released from AOD slag, the temperature-dependent maximum availability leaching test was performed. To determine the controlling mineralogical phases of chromium released from AOD slag, a Visual MINTEQ simulation was established based on Vminteq30 and the FactSage 7.0 database. The leaching tests indicated that the leaching availability of chromium was slight and mainly consisted of trivalent chromium. Aging of AOD slag under the atmosphere can oxidize trivalent chromium to hexavalent chromium, which could be leached out by rainwater. According to the simulation, the chromium concentration in leachates was controlled by the freely soluble pseudo-binary phases in the pH = 7.0 leaching process and controlled by the CrO phase in the pH = 4.0 leaching process. Chromium concentrations were underestimated when the controlling phases were determined to be FeCrO and MgCrO. Facilitating the generation of the insoluble spinel-like phases during the cooling and disposal process of the molten slag could be an effective approach to decreasing the leaching concentration of chromium and its environmental risk.
氩氧脱碳（AOD）渣是不锈钢精炼过程中的副产品。AOD渣中存在的铬可能会浸出，对环境构成严重威胁。为评估AOD渣中铬的浸出毒性，进行了温度依赖性最大可利用性浸出试验。为确定AOD渣中铬释放的控制矿物相，基于Vminteq30和FactSage 7.0数据库建立了Visual MINTEQ模拟。浸出试验表明，铬的浸出率较低，主要为三价铬。AOD渣在大气中老化会将三价铬氧化为六价铬，六价铬可被雨水浸出。模拟结果表明，在pH = 7.0的浸出过程中，浸出液中的铬浓度受自由溶解的假二元相控制，在pH = 4.0的浸出过程中受CrO相控制。当确定控制相为FeCrO和MgCrO时，铬浓度被低估。在熔渣冷却和处置过程中促进生成不溶性尖晶石类相可能是降低铬浸出浓度及其环境风险的有效方法。
