Ferrochromium slag is a by-product of ferrochromium production via the smelting of chromite ores. The mechanical properties of this slag make it a potential material to be used as an inexpensive construction material, the utilization of which can reduce the use of natural resources. Despite its potential use, ferrochromium slag is treated as a waste due to environmental and health concerns regarding the leaching of its heavy metal content, the most concerning of which is carcinogenic chromium (VI). Research has shown that the spinel phase in ferrochromium slag stabilizes chromium by trapping it in the spinel structure and preventing its leaching to the environment. This study investigates the effect of heat treatment and composition change on spinel formation in ferrochromium slag and subsequently on the stabilization of chromium. Slag samples of the MgO–Al₂O₃–SiO₂–CaO–FeO–Cr₂O₃ system were synthesized at 1650 °C for 10 h in a vertical tube furnace. Samples were heat treated after synthesis by holding them at 1400, 1475, and 1550 °C for 12 h before quenching. Leaching tests on heat-treated slag samples reveal that samples held at 1400 °C have the lowest chromium leachability. With a holding temperature of 1400 °C, slag samples were prepared with variations in Al₂O₃ content in the range of 0–20%. Higher Cr leaching is observed from samples as the Al₂O₃ content increases. Similar heat-treated samples were prepared with constant Al₂O₃ content and basicity (CaO/SiO₂) varying from 0.3 to 0.7. An increase in basicity increases the amount of Cr released from the samples during leaching experiments.

Graphical Abstract

中文翻译：

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铬铁渣中铬的稳定化用作骨料

铬铁渣是铬铁矿冶炼生产铬铁的副产品。这种炉渣的机械性能使其成为一种潜在的材料，可用作廉价的建筑材料，利用这种材料可以减少自然资源的使用。尽管铬铁渣具有潜在用途，但由于其重金属含量的浸出导致环境和健康问题，铬铁渣仍被视为废物，其中最令人担忧的是致癌铬 (VI)。研究表明，铬铁渣中的尖晶石相通过将铬捕获在尖晶石结构中并防止其浸出到环境中来稳定铬。本研究调查了热处理和成分变化对铬铁渣中尖晶石形成以及随后对铬稳定性的影响。₂ O ₃ –SiO ₂ –CaO–FeO–Cr ₂ O ₃体系在立式管式炉中于 1650 ℃下合成 10 h。样品在合成后通过在淬火前在 1400、1475 和 1550 °C 下保持 12 小时进行热处理。热处理炉渣样品的浸出试验表明，保持在 1400 °C 的样品的铬浸出率最低。_{在 1400 °C 的保持温度下，制备了 Al 2} O ₃含量在 0-20% 范围内变化的矿渣样品。_{随着 Al 2} O ₃含量的增加，从样品中观察到更高的 Cr 浸出。_{用恒定的 Al 2} O ₃制备类似的热处理样品含量和碱度（CaO/SiO ₂）从 0.3 到 0.7 不等。在浸出实验期间，碱度的增加会增加从样品中释放的 Cr 量。

图形概要