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Jingdong Huang, and Xiao Yang, Oxygen-assisted zinc recovery from electric arc furnace dust using magnesium chloride, Int. J. Miner. Metall. Mater., 31(2024), No. 10, pp.2300-2311. https://dx.doi.org/10.1007/s12613-024-2837-4
Jingdong Huang, and Xiao Yang, Oxygen-assisted zinc recovery from electric arc furnace dust using magnesium chloride, Int. J. Miner. Metall. Mater., 31(2024), No. 10, pp.2300-2311. https://dx.doi.org/10.1007/s12613-024-2837-4
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氧气辅助MgCl2氯化:电炉粉尘中锌的高效回收方法

摘要: 电炉炼钢过程中产生的粉尘作为主要的二次锌资源,具有显著的回收价值。然而,锌在电炉粉尘中主要以结构极其稳定的铁酸锌(ZnFe2O4)的形式存在,其分离回收存在很多挑战。针对这一问题,本文提出了一种氧气辅助MgCl2氯化的技术思路,用于实现电炉粉尘中锌的选择性氯化分离。本文重点阐明了氧气对熔融MgCl2氯化ZnFe2O4反应的影响规律和机制。研究结果表明,MgCl2可有效破坏ZnFe2O4的晶体结构,而氧气的存在会促进MgFe2O4的形成,抑制铁的氯化,有利于锌的高选择性氯化分离。动力学分析表明,在氧气辅助下,ZnFe2O4中的锌被MgCl2氯化的过程遵循扩散控制的未反应核模型。基于上述发现,本文进一步完成了技术思路的验证,利用氧气辅助MgCl2氯化从实际电炉粉尘中提取了富含ZnCl2的产物。在1000°C的空气中、质量比为0.6:1的MgCl2与电炉粉尘反应40 min后,锌的氯化率高达97%,而铁的氯化率低于1%,所得产物中ZnCl2的质量分数超过85%。本研究为含锌粉尘的资源回收技术开发提供了有益参考。

 

Oxygen-assisted zinc recovery from electric arc furnace dust using magnesium chloride

Abstract: Electric arc furnace (EAF) dust is an important secondary resource containing metals, such as zinc (Zn) and iron (Fe). Recovering Zn from EAF dust can contribute to resource recycling and reduce environmental impacts. However, the high chemical stability of ZnFe2O4 in EAF dust poses challenges to Zn recovery. To address this issue, a facile approach that involves oxygen-assisted chlorination using molten MgCl2 is proposed. This work focused on elucidating the role of O2 in the reaction between ZnFe2O4 and molten MgCl2. The results demonstrate that MgCl2 effectively broke down the ZnFe2O4 structure, and the high O2 atmosphere considerably promoted the separation of Zn from other components in the form of ZnCl2. The presence of O2 facilitated the formation of MgFe2O4, which stabilized Fe and prevented its chlorination. Furthermore, the excessive use of MgCl2 resulted in increased evaporation loss, and high temperatures promoted the rapid separation of Zn. Building on these findings, we successfully extracted ZnCl2-enriched volatiles from practical EAF dust through oxygen-assisted chlorination. Under optimized conditions, this method achieved exceptional Zn chlorination percentage of over 97% within a short period, while Fe chlorination remained below 1%. The resulting volatiles contained 85wt% of ZnCl2, which can be further processed to produce metallic Zn. The findings offer guidance for the selective recovery of valuable metals, particularly from solid wastes such as EAF dust.

 

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