A huge amount of ash and slag materials (ZSM) is formed during the operation of thermal power plants and only 10% of the total volume of these wastes is now directed to effective disposal.
As a rule, ZSM is used in construction as a substitute for sand and an additive to building mixes. However, according to scientists of the Institute of Chemical and Oil and Gas Technologies (IHNT) of KuzSTU, the coal waste of Kuzbass is also rich in rare and rare earth elements that have a huge industrial value.
"ZSM can be considered as deposits, as ores located on the surface. Niobium, yttrium, zirconium, silver, gold, strontium, vanadium and other rare-earth, rare and scattered elements-which are referred to as "a gram is more expensive than a ton" – are present in industrially significant concentrations in all coal-mining regions of Kuzbass. High-tech industries around the world require constantly growing volumes of these materials," says Professor Tatyana Cherkasova, director of the Institute of Chemical and Oil and Gas Technologies.
IHNT scientists are developing methods for the effective extraction of valuable elements from the by-products of the coal industry. First, using standard enrichment methods, the elements present in the ZSM in macro quantities are separated. In the future, they can be used as a safe component of building mixes. Iron compounds that can be used in the metallurgical industry are easily extracted by magnetic separation methods.
The remaining " heavy "elements can be separated from the" light "ones by mechanical enrichment in installations of the" hydrocyclone "or"screen" type. According to KuzSTU scientists, the most promising method of extracting the most valuable elements is flotation extraction using sodium alkyl sulfates and a number of other reagents.
The equipment for these processes can be installed both at thermal power plants and at coal-processing plants. The launch of such production facilities on the basis of existing ash dumps will allow to eliminate or reduce them over time, seriously improving the environmental situation.
The research is carried out within the framework of the project "Complex processing of coal mining and coal refining waste with the release of rare and rare earth elements" of the complex scientific and technical program "Clean coal-green Kuzbass" of the REC "Kuzbass".