基于物质流分析的高铝粉煤灰制备莫来石过程重金属迁移规律及环境风险研究

High alumina fly ash which mainly produced from the west of Inner Mongolia in China had occupied a lot of land resources，but also caused some serious damage to the ecological environment. However，because of the high grade aluminum and silicon，it can be recycled by making Al-Si system refractory materials.However，there are few systematic studies on the environmental impact of such secondary resource-based products from the view of whole life cycle，especially the regional environmental risk research caused by the migration and transformation of heavy metals.The paper systematically studied the possible environmental risks from the migration of different heavy metals in mullite produced by high alumina fly ash based on the material metabolism and life cycle analysis methods，combined with Nemero pollution index and Hakanson risk model. The results showed that：the release of all various heavy metals in high alumina fly ash presented on significantly increases trends after physical ball milling activation process，more than 80% of the iron group elements represented by Cr and Mn migrate to the poly aluminium residue which produced by the acid activation process，while the metal ore-forming elements represented by Zn，Pb and Cu migrate in the acid activation and alkali desilication processes，and Cr，Mn，Zn，Pb and Cu which finally enter to the mullite products are 20%，9%，24%，22% and 24%，respectively. In addition，there were also exited great potential ecological environment risks of poly aluminum residue，which exceeds the extremely strong level standard by 6.6 times，and the risk factor of Cr is the most prominent；the heavy metal leaching toxicity of calcium silicate products is Zn>Mn>Cu>Pb>Cr，and the heavy metal leaching toxicity of mullite products is Mn>Cu>Zn>Pb>Cr，but they were all far below the groundwater quality standard limit. In general，although more than 75% of fly ash has been reduced while mullite products are prepared，the secondary solid waste disposal problems such as polyaluminum residues generated therefrom still need to be focused. At the same time，this study can further provide scientific basis for the comprehensive utilization of solid waste，especially for the environmental risk control of the recycling process of heavy metal containing solid waste，and also provide ideas for the ecological design of solid waste recycling products.