基于生命周期评价的铜尾渣资源化利用环境效益——以制取蒸压砖为例

Environmental benefit of copper tailings resource utilization based on life cycle assessment:A case study of autoclaved bricks production

我国每年产生的铜尾渣超过1 500万吨,持续堆存会造成严重的环境危害,而资源化处理则通常能够充分利用铜渣当中的资源并一定程度上降低环境危害。通过生命周期评价方法,对铜尾渣资源化利用制取蒸压砖并副产铜精矿、铁精矿和重介质的工艺过程的环境影响进行了分析。结果表明,该技术方案最主要的环境影响为人体毒性(33 886 kg 1,4-二氯苯当量/资源化1 000吨铜尾渣);水泥生产阶段环境负荷最高,在7种环境影响类别中均有最高的贡献;贡献最明显的关键物质为氮氧化物,其对富营养化、酸化、光化学污染贡献占比分别为94.1%、42.0%和24.3%。将生产蒸压砖和副产的铜精矿、铁精矿、重介质所避免的环境影响纳入考虑范围之后,发现该铜尾渣资源化方案能够取得明显的环境效益。

More than 15 million tons of copper tailings are produced in China each year,and the continuous stockpiling of them will cause serious environmental harm,while the recycling treatment can usually make full use of the resources in the copper tailings and reduce the environmental harm to some extents.This article analyzes the environmental impacts of the process of making autoclaved bricks from copper tailings and by-product copper concentrate,iron concentrate and dense medium by life cycle assessment method.The results show that the most important environmental impact of the technical scheme is human toxicity(33 886 kg 1,4-DCB eq./1 000 tons of recycled copper tailings).The environmental load of cement production stage is the highest,and it has the highest contribution among the seven environmental impact categories.The most significant contribution of the key substance is nitrogen oxide,which contributes 94.1%,42.0% and 24.3% to eutrophication,acidification and photochemical pollution respectively.Considering the offset of the products of autoclaved bricks and the by-products of copper concentrate,iron concentrate and dense medium,the recycling of copper tailings can achieve obvious environmental benefits.