Recent Developments in the Utilization of Western U.S. Coal Conversion Ash

Abstract

ABSTRACTThe utilization of ashes from combustion or gasification of western U.S. coals offers many possibilities for useful products. Of the possible uses, the following have been identified in an earlier study [1] as having sufficient potential for laboratory development and testing: mineral wool, sulfur concrete, high flexural-strength ceramics, replacement of cement in concrete, and road stabilization. Three lignite-derived ash products from the Beulah, ND, site were used in the present study: fixed-bed gasification ash; a dry scrubber ash; a combination bottom ash/economizer ash from an electrical power plant, Where possible, ASTM fabrication and testing procedures were used. Mineral wool of similar physical character to commercial wool and at lower potential cost was produced using 100 percent of various western ashes. Sulfur concrete utilizing 80% ash and 20% modified sulfur developed flexural and compressive strengths in excess of 2,250 and 5,000 psi, respectively. An economically competitive vitrified ceramic product with flexural strength above 7,800 psi was produced from a mixture of 50% ash, 45% sand, and 5% clay. By using a total ash mixture of 26% gasifier ash and 74% combustion ash, a very satisfactory, economical and durable roadbed material was developed. The replacement of up to 50% of the cement in concrete with western fly ash produces economical, high strength concrete.