A New Method (Ball Milling and Sodium Sulfide) for Mechanochemical Treatment of Soda Ash Chromite Ore Processing Residue.
A New Method (Ball Milling and Sodium Sulfide) for Mechanochemical Treatment of Soda Ash Chromite Ore Processing Residue.
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DOI：
10.1016/j.jhazmat.2021.125601
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发表时间：
2021-03
影响因子：
13.6
通讯作者：
Yan Sun;Yaguang Du;Jirong Lan;Weixi Zhan;Tian C. Zhang
中科院分区：
文献类型：
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作者：
Yan Sun;Yaguang Du;Jirong Lan;Weixi Zhan;Tian C. Zhang
纯碱铬铁矿加工残渣（COPR）中的六价铬对环境有害，开发低成本、高效、有效的处理方法势在必行。在此，开发了一种新方法（球磨 + 硫化钠）用于机械化学处理水浸 COPR（W-COPR，约 900 mg/kg 非交换性 Cr(VI)，大部分为铬铁矿结合）。在 S2 与 Cr(VI) 的化学计量比为 5、研磨速度为 200 rpm、研磨时间为 30 分钟、球粉重量比为 8.5 的情况下，处理后的总 Cr(VI) 为 76.88 mg/kg，毒性特征浸出程序 (TCLP) 总 Cr 值为 1.15 mg/L。矿物释放分析仪 (MLA) 分析结果显示，铬铁矿晶粒释放量增加 10%，晶粒尺寸减小，有利于铬铁矿结合 Cr(VI) 的还原。在镁铁氧体封装的 Cr(VI) 上也观察到类似的效果。颗粒聚集和玻璃相胶体沉淀的形成可能会阻碍 Cr(VI) 的还原。 X 射线吸收近边结构 (XANES) 分析结果表明，该处理方法将实际 Cr(VI) 浓度降低至 312 mg/kg，Cr(VI) 还原效率达到 98%。总体而言，新方法简单高效，为未来的工业应用提供了指导。
Hexavalent chromium in soda ash Chromite Ore Processing Residue (COPR) is harmful to the environment, it is imperative to develop a low cost, efficient, and effective treatment. Herein, a new method (ball milling + sodium sulfide) was developed for mechanochemical treatment of water-leached COPR (W-COPR, about 900 mg/kg non-exchangeble Cr(VI) and mostly chromite bounded). Under a stoichiometric ratio of S2-to Cr(VI) of 5, milling speed of 200 rpm, milling time of 30 min, ball-to-powder weight ratios of 8.5, and, a total Cr(VI) of 76.88 mg/kg and a Toxicity Characteristic Leaching Procedure (TCLP) total Cr value of 1.15 mg/L were achieved after treatment. Results of the mineral liberation analyser (MLA) analyses showed 10% increase of chromite grains liberation and grain size reduction were beneficial to the chromite-bound Cr(VI) reduction. Similar effects were also observed on magnesioferrite encapsulated Cr(VI). Particle aggregation and formation of glass phase colloid precipitation could potentially impede Cr(VI) reduction. Results of X-ray absorption near edge structure (XANES) analyses indicated that the treatment method reduced the actual Cr(VI) concentration to 312 mg/kg with Cr(VI) reduction efficiency of 98% being achieved. Overall, the new method is simple and efficient, and provides a guidance for future industrial application.