二次铝灰特性及其解毒利用研究进展

Research progress on the characteristics of secondary aluminum dross and its detoxification and utilization

  • 摘要: 二次铝灰是铝生产加工过程中不可避免地产生的一种典型危险固体废弃物,其中不仅含有大量AlN、氯盐、氟化物等有害物质,还包含大量的铝,是一种利用价值极大的潜在铝资源。本文综述了二次铝灰的来源、性质以及无害化和资源化研究进展。研究结果表明:火法工艺着重于实现二次铝灰的规模利用,处理效率高,常见的产品包括建筑材料、耐火材料、铝酸钙脱硫剂等。但由于盐的大量挥发,火法工艺存在能耗高,设备腐蚀严重、对原料成分限制大等问题。湿法工艺则侧重于实现二次铝灰的无害化,是一种环境友好、对原料包容性更大的解毒方式,但酸碱浸出过程废液排放量较大,水浸过程AlN脱除不完全。二次铝灰的高效解毒和规模化高值利用不仅可以解决危险固体废弃物大量堆存带来的潜在环境风险,同时可以实现铝资源的最大化利用,对生态环境和铝工业的健康发展意义重大。建议根据二次铝灰盐含量对其进行资源整合,分类处理。同时加强二次铝灰在耐火材料、铝酸钙脱硫剂等高附加值领域的利用。

     

    Abstract: Secondary aluminum dross is a typical hazardous solid waste inevitably generated during aluminum production and processing. It contains not only a large amount of AlN, chlorine salts, fluoride and other hazardous substances, but also about 40% of aluminum, which is a potential aluminum resource with great utilization value. The sources and properties of secondary aluminum dross, as well as the progress of research on the harmless and resourceful utilization, are reviewed in this paper. The research results show that the pyrometallurgical process focuses on achieving large-scale utilization of secondary aluminum dross with high processing efficiency, and the common products include cement, refractory materials, calcium aluminate refining agent, ceramic heat storage ball and so on. However, due to the large amount of volatilization of salts, the pyrometallurgical process suffers from high energy consumption, serious corrosion of equipment, and large restrictions on the composition of raw materials. The hydrometallurgical process, on the other hand, focuses on achieving the harmlessness of secondary aluminum dross, which is an environmentally friendly and more inclusive detoxification of raw materials. However, the acid and alkali leaching process has a large amount of waste liquid discharge, and the water leaching process has incomplete removal of AlN, which requires further disposal. Efficient detoxification and large-scale high-value utilization of secondary aluminum dross can not only solve the potential environmental risks caused by hazardous solid waste stockpiling, but also realize the maximum utilization of aluminum resources, which is of great significance to the ecological environment and the healthy development of the aluminum industry. It is recommended that the secondary aluminum dross be resourced according to its salt content and categorized for disposal. Meanwhile, the utilization of secondary aluminum dross in high value-added fields such as calcium aluminate refining slag, ceramic heat storage ball and refractory materials is strengthened.

     

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