随着我国煤气化行业不断发展,产生的煤气化渣总量也越来越多,已成为急需解决的问题之一。为充分利用气化灰渣,拓宽其应用场景,体现潜在的资源价值,已在建材、陶瓷、玻璃、分子筛、催化剂等行业进行了大量探索,并得到成功运用。然而,煤气化过程中,煤中有害重金属元素(Hg、Cr、Cd、Pb、Zn、Ni)会残留在气化灰渣中,其可能随扬尘、降水等释放或浸出到环境中,对生态环境和人类生命健康造成不利影响,制约煤气化渣综合利用。在气化过程中,煤中重金属的迁移受气化温度、气氛和压力等条件影响,不同种类重金属受这些条件的作用方式和影响程度也不同。对于煤气化渣中重金属,其浸出率受浸出液pH、浸出温度、固液比、颗粒尺寸和浸出时间等因素影响,其中浸出液pH是主要影响因素。为稳定灰渣中重金属,降低重金属释放和浸出,减少环境污染,总结梳理了煤气化渣中重金属的固化处理技术,并根据固化方式分为水泥固化、热处理固化、水热处理固化、添加剂固化、化学共沉淀固化和矿化协同固化等6种方式。

With the continuous development of the coal gasification industry in China, the total amount of coal gasification slag is also in⁃creasing, and has become one of the urgent problem. In order to make full use of gasification slag, broaden its application scenario and re⁃flect the potential resource value, a lot of exploration has been carried out in the industries of construction materials, ceramics, molecularsieves, catalysts, etc., and it has been successfully used. However, during the coal gasification process, harmful heavy metal elements(Hg, Cr, Cd, Pb, Zn, Ni) in coal will remain in the gasification slag, which may be released or leached into the environment with pre⁃cipitation, causing adverse effects on the ecological living environment and human life and health, and affecting the comprehensive utiliza⁃tion of coal gasification slag. In the process of gasification, the release of heavy metals in coal is affected by the gasificationtemperature, mode and atmosphere, and different kinds of heavy metals are affected by these conditions in different ways and to differentdegrees. For heavy metals in gasification slag, the leaching rate is influenced by leachate pH, leaching temperature, solid-liquid ratio,particle size and leaching time, among which leachate pH is the main influencing factor. In order to stabilize the heavy metals in slag, re⁃duce the release and leaching of heavy metals and reduce the pollution to the environment, the sequestration treatment technology of heavymetals in coal gasification ash slag is systematically summarized and classified into six ways, such as cement sequestration, heat treatmentsequestration, hydrothermal treatment sequestration, additive sequestration, chemical co-precipitation sequestration and co-consolidationof mineralization according to the sequestration method.

0 引言

1 重金属在煤气化过程中迁移规律

   1.1 汞（Hg）

   1.2 铬（Cr）

   1.3 镉（Cd）

   1.4 铅（Pb）

   1.5 锌（Zn）

   1.6 镍（Ni）

2 重金属在气化灰渣中浸出行为

   2.1 汞（Hg）

   2.2 铬（Gr）

   2.3 镉（Cd）

   2.4 铅（Pb）

   2.5 锌（Zn）

   2.6 镍（Ni）

3 气化灰渣中重金属的固化脱毒

   3.1 水泥固化

   3.2 热处理固化

   3.3 水热处理固化

   3.4 机械混合固化

   3.5 化学沉淀固化

   3.6 矿化协同固化

4 结语和展望