水泥窑协同处置固体废物过程中有害物质迁移转化机理研究

The integrated disposal of solid wastes using cement kilins has been considered as a promissing arroach. However, the transformation mechanisms and partitioning behavior of harmful matters have rarely been investigated during the integrated processing of solid wastes. The project therefore focused on investigating the migration and transformation mechanisms of harmful matters through analyzing the raw materials for cement production, the treated solid wastes, cement clinker and the chemical compositions of harmful elements in particulate matters. Therefore, the distribution behaviors of harmful matters in multi-components and multi-phases will be revealed. To obtain the distribution mechanisms between the multi-phases, the influences of heavy metal contents and phases in solid wastes on the phase transformation were investigated during the preparation of cement clinker. The distribution behavior of heavy metals among multi-phases will be explored under different experimental conditions, including temperature, pressure, and oxygen partial pressure. The distribution characteristics of heavy metals and organic pollutants on the surface of particulate matter in flue gas will be explored, and the catalytic effect of heavy metals on organic pollutants will be therefore elucidated under different conditions. A model will be constructed to describe the transformation and migration mechanisms during the overall process of synergistic disposal for solid wastes, so as to develop and improve an environmentally friendly technical process for cement kiln co-disposal of solid wastes.

水泥窑协同处置固体废物被认为是一种具有前景的技术，然而，处置过程中重金属和有机污染物等有害物质的迁移转化机制尚缺乏系统研究。本项目通过对水泥生产原料、所协同处置的固体废物、水泥熟料、颗粒物等的化学组成、赋存形态及迁移转化规律等进行系统研究，揭示有害物质在多组元、多物相中的转化分配机制。研究重金属的含量及赋存形态对水泥熟料烧成过程中物相转化的影响规律，明确重金属元素在多物相之间的分配规律。探明不同条件（温度、压力、氧分压）下有害物质在多物相间的分配行为。探索研究烟气中颗粒物表面的重金属和有机污染物的赋存形态，阐明不同条件下颗粒表面重金属对有机污染物的催化转化机理。构建水泥窑协同处置固体废物全过程中有害物质的迁移转化模型，从而完善和发展环境友好型水泥窑协同处置固体废物工艺体系。

随着中国城镇化和工业化的快速发展，固体废物尤其是危险废物污染问题日益突出，已成为影响生态环境安全、社会和谐稳定的重要因素。利用水泥窑处置固体废物目前被认为是一种比较具有前景的技术。本项目以水泥窑协同处置固废/危废为研究对象，系统研究并获得了水泥熟料中重金属的分布行为、化学形态、固化机制，揭示了As、Cr、Cu和Zn等典型重金属元素在熟料制备过程中的转化迁移机制。系统地研究了水泥窑协同处置固废过程中烟气中颗粒物的排放特性，表明水泥生产过程会排放出大量的颗粒物，并且一些有害重金属会富集在这些颗粒物上，而固废的添加则会促进重金属的富集作用。固废的添加会导致颗粒物中SO42-，以及二次有机物含量的增加。单颗粒分析表明，颗粒物可分为富硫、富钠、富钾、金属、飞灰、有机、烟尘、矿物以及富钙颗粒等九大类，据此，我们提出了相应的混合颗粒物的两步形成模型。系统地研究了水泥窑协同处置固废过程中重金属的分配、扩散、沉降以及在周围土壤中的分布行为，研究表明大部分的重金属都会在水泥厂附近的土壤大约400-800 m范围内富集。根据富集因子可知，水泥厂附近土壤受到Cd元素的中度污染，As、Cr、Ba和Zn元素的轻度污染。.本项目的研究为利用水泥窑环境友好协同处置固体废物提供技术支撑，从而为实现固体废物的高效清洁利用和可持续性发展奠定坚实的理论基础。