Carbonate Bonding of Coal Refuse.

摘要

A laboratory study of the variables which affect the properties of the carbonate bonded coal refuse has been made. The carbonate bonding process utilizing coal refuse as a fill material consists of mixing coal refuse with water and lime hydrate,compacting the mixture,and reacting it with a carbon-dioxide-rich gas to form a coherent structure bonded by a matrix of calcite crystals. The resulting carbonate bonded coal refuse can be used in road building or as a coal refuse pile sealant to minimize acid mine water pollution. Four types of coal refuse were investigated--a relatively unoxidized and highly oxidized bituminous coal refuse and a relatively unoxidized and highly oxidized anthracite coal refuse. It was found that compressive strengths of 2200to 4400psi were obtained for the four types of coal refuse investigated using up to 12percent lime hydrate and 9to 15percent water. In general,the compressive strength of the carbonate bonded coal refuse increases with increasing lime hydrate content,reaction time and carbon dioxide concentration in the carbonate bonding reaction gas. The air and water permeability of carbonate bonded coal refuse was found to be comparable to concrete. An approximate cost comparison between carbonate bonded coal refuse and other construction materials and techniques indicated that the carbonate bonding process utilizing coal refuse is the least cost means available for coal refuse pile sealing and road building. (Author)