高铝粉煤灰资源化过程重金属环境影响研究

Migration and emission of heavy metal elements in the multi-resource utilization of high alumina fly ash process

针对高铝粉煤灰碱石灰烧结多资源利用工艺过程中重金属元素迁移规律和潜在环境影响量化问题,基于物质流分析方法,分析该工艺中重金属元素的边界输入输出和内部迁移规律.结果表明,输入端54%的铅元素由工业过程废弃物即高铝粉煤灰带入,其余来自工业原材料.输出端64%的铅元素进入产品,其余部分进入废弃物.该工艺主要环境排放节点在烧结和水泥生产环节.通过定义相对环境排放指数(REEI),比较分析该工艺与拜耳法工艺重金属排放情况.结果表明,该工艺单位氧化铝产量铅元素净排放显著降低,铬元素环境排放量与拜耳法基本持平,说明高铝粉煤灰碱石灰烧结多资源利用工艺不仅可以实现高铝粉煤灰的综合利用,也可以显著降低氧化铝产品的重金属环境影响.

Substance flow analysis was adopted to study the migration behavior and quantitative potential environmental impact of heavy metal elements in multi-resource utilization of high alumina fly ash process. The input, output, and internal migration of heavy metals in this process are obtained. The result showed that 54% of lead was from fly ash, and the other was from industrial raw materials. 64% of lead was brought out through products,and the other through wastes. The environmental emission of this process were from sintering and cement production. The Relative Environment Emission Index （REEI） was defined to compare this process with the Bayer process. The result showed that the lead emission of this process was significantly less than Bayer process and the chromium emission of this process was fair with Bayer process. It meaned that this process could not only utilize the resource of high-alumina fly ash but also significantly reduce the environmental impact of heavy metals in alumina product.