Management of Fly Ash to Synthesise Geopolymers and Zeolites

The purpose of the article was to conduct an in-depth literature review on the possibilities of managing combustion by-products (mainly fly ash) in the context of a closed-loop economy. First, information on the chemical composition of fly ash in Poland was collected and compared with the composition of fly ash in other European countries. The authors concentrated on describing methods for synthesizing geopolymers and zeolites using fly ash as a substrate. By-products of zeolite synthesis, which are strongly alkaline solutions, can be used as a substrate in the synthesis of geopolymers. A concept has been proposed to combine the synthesis of zeolites and geopolymers into a single process to close the material loop. The search for comprehensive technological solutions that take into account the ideas of a closed-loop economy is essential in an era of resource depletion, and this literature review encapsulates this topic area.