Review on coal fly ash generation and utilization for resolving mercury contamination issues in Central Asia: Kazakhstan

The generation of coal fly ash (CFA) in coal-fired power plants worldwide has been a major concern over the past few decades. CFA as a by-product possesses unique properties and chemical composition that could be utilized in resolving mercury contamination issues in Central Asia, particularly in Kazakhstan. This review article gives an overview of coal generation capacity and evaluation of the current state of electricity production and ecological concerns related to CFA accumulation. We provide a detailed comparison of the physical properties and chemical compositions of three types of CFAs from Kazakhstani power plants, and present potential approaches to help alleviate mercury contamination issues. Furthermore, this review highlights the current state of mercury contamination in artificial Lake Balkyldak and in the Nura River of the North and Central regions of Kazakhstan. Of particular interest is the appropriate utilization of CFAs in resolving mercury contamination issues by highlighting and comparing the state-of-the-art technology of porous and non-porous materials and currently reported in the literature.