Characteristics and assessment of the suitability of coal-rich mining waste in the production of ceramic building materials

Abstract

Hard coal mining involves the generation of large quantities of waste materials. For every 1000 kg of hard coal produced in Poland an average of approx. 400 kg of different kinds of waste material is generated. Environmental regulations and new approaches based on the Clean Coal Technologies require manufacturers to recover or neutralize the generated wastes. Technological progress and the development of clean coal technologies have led to the wastes being treated as products for other industries. The ability to use the waste material depends on their chemical and mineral composition. Mining wastes are characterized by different properties depending on the stage of the coal-enrichment process in which they are formed. In spite of ever more efficient coal-enrichment technologies, in addition to mineral material, there is still a significant amount of carbon in the wastes that can be recovered in various ways. After the coal recovery process, the waste material is wet (20-30%), has a thick pasty consistency and is deposited in landfills, thus representing a hazard and nuisance to the environment. This study focuses on the characteristics of the raw waste material and the possibility of using it in the production of building materials. Mineral compositions were tested with XRD and STA methods and the characteristics of thermal properties of waste material were investigated using STA and heating microscopy. Gases released during thermal processing of the waste material were analysed by the EGA / MS method. Particle size distribution was measured and the specific surface area of the waste mud samples was calculated. Preliminary analysis was carried out to assess the feasibility of using this waste as a raw material in the production of fired ceramic building materials.