O. E. Manz

Use of a Database of Chemical, Mineralogical and Physical Properties of North American Fly Ash to Study the Nature of Fly Ashand Its Utilization as a Mineral Admixture in Concrete

A database of chemical, mineralogical and physical characteristics of North American fly ashes has been assembled by the Western Fly Ash Research, Development and Data Center. One-hundred and seventy-eight representative ashes were divided into three groups according to their analytical CaO content: low-calcium, <10%; intermediate-calcium, 10–20%; high-calcium, 20+%. Statistical analyses were performed within each of the three groups. Thirty-two plots relating chemical composition, mineralogy and physical test results are presented. Extensive discussions relating the chemistry and mineralogy of the ash to the source coal, the distribution of the chemical constituents among crystalline and glassy phases, and the reactions of these phases in concrete are given. The consistency of high-calcium fly ash generated at a Midwestern U.S. power station fired with Wyoming bituminous coal was studied using ninety-three ashes collected over a two year period. The availability of mineralogy for each ash leads to a more thorough understanding of the bulk chemical and physical test results used in evaluating fly ashes for utilization, and in modeling their behavior after disposal

Utilization of by-products from western coal combustion in the manufacture of mineral wool and other ceramic materials

Abstract The ash by-products from combustion or gasification of western U.S. coals have chemical and mineralogical characteristics that lend themselves to utilization in ceramic materials. Laboratory and pilot-scale fabrication of four such materials has been studied. Cyclone slag from four lignite-fired power plants and a dry scrubber ash have been fabricated into mineral wool insulation in a pilot-scale cupola. Extruded and fired mixtures of fly ash, clay and ground glass have produced ceramics with extraordinary high flexural strength. Ceramic glazed wall tile that utilize fly ash in place of clay have been prepared and shown to meet most specifications for fired clay tile. Both fired and unfired dry-pressed brick containing 100% western fly ash have met ASTM specifications for fired clay brick.

Correlations of Chemistry and Mineralogy of Western U.S. Fly Ash

Fly ashes derived from low-rank coals mined principally in Montana, Wyoming and North Dakota are being studied by the Western Fly Ash Research, Development and Data Center [1]. Previous studies of the mineralogy of western U.S. fly ash by McCarthy et al. [1–3] using x-ray diffraction (XRD) form the framework of the present study. A database of chemical, mineralogical and physical properties, along with precursor coal characteristics, is being assembled. Based on studies to date of several hundred fly ash samples derived from lignite and subbituminous coals, as well as from several bituminous ashes, correlations of chemistry and mineralogy have been hypothesized and are being tested. These correlations are discussed below.

Utilization of Fly Ash in Roadbed Stabilization: Some Examples of Western U.S. Experience

In contrast with pozzolanic bituminous fly ashes, the western American lignite and subbituminous fly ashes are both pozzolanic and cementitious. During the last three years, there has been much research and actual use of western ash alone and with lime or cement for roadbed stabilization. In contrast with lime stabilization which only applies to clay, the western ashes can be used to stabilize clay as well as silty and granular soils. Fly ash is moving from the experimental to standard alternative for pavement in many states. Some examples of western U.S. experience will be presented.