Use of Ash and Slag Waste from Thermal Power Plants for the Production of Rare Earth Compounds and Ceramic Membranes

The processing of ash/slag wastes were studied, while a complete analysis of the bottom ash of the Luchegorsk thermal power plant in the Primorsky Territory was carried out, and a study was performed on the separation of rare earth elements by various methods. The ash was previously cleaned from unburned coal (underburnt) and iron oxides, the resulting product was processed with various methods. Isolation and separation of products was carried out in several stages. The acidity of the medium was determined, which corresponds to the quantitative precipitation of iron and aluminum matrix ions depending on the initial concentrations of the solutions. Silicon oxide of 97% purity with a high specific surface area was obtained, as well as a solid product with a content of rare earth elements more than 100 times higher than in the original ash samples. The content of rare earth elements in the final product is 74.5% of the content of these elements in the original material, and the product is also enriched with other trace elements such as zirconium, hafnium, and tungsten. When the ash is processed, solid waste remains, which can be further utilized to fabricate ceramic materials and membranes with high technical performance.