The electrical resistance and compressive strength were measured to gain a better under- standing of the sintering characteristics of low-rank coal ashes involved in deposit formation in combustion systems. Low-rank coal ashes were prepared by the standard ASTM ashing procedures at 750℃ and then separated into three different particle size fractions. The sinter point determined by the electrical resistance method decreased with decreasing particle size at three different particle size fractions of each coal ash. The compressive strength test was made as a function of temperature in the range 750-950℃. At a given sintering temperature, strength of the sintered ash was inversely proportional to particle size. For any given particle size of each coal ash, the strength increased with increasing sintering temperature. X-ray diffraction of the sintered coal ashes showed that, as sintering temperature increased, there was an inverse relationship between sinter strength and the amount of anhydrite in the sintered ash, and a direct relationship between strength and the amount of hauyne.

Sintering of Coal Ash Sinter Point Compressive Strength Ash Deposition

Annual Book of ASTM Standards, "Fusibility of Coal Ash and Coke Ash," ASTM, Philadelphia (1990)
Barnhart DH, Williams PC, Trans. AIME, 78, 1229 (1956)
Benson SA, "Laboratory Studies of Ash Deposit Formation During the Combustion of Western U.S. Coals," Ph.D. Dissertation, The Pennsylvania State University (1986)
Borio RW, Levasseur AA, "Mineral Matter and Ash in Coal," Vorres, K.S., Ed., American Chemical Society, Washington, D.C. Chapter 21 (1986)
Conn RE, "A Preliminary Study of the Sintering Characteristics of Coal Ash as Related to Utility Boiler Ash Deposition," M.S. Thesis, The Pennsylvania State University (1984)
Cumming JW, J. Inst. Energy, Sep., 153 (1980)
Dering IS, Dubrovskii VA, Dik EE, Thermal Eng., 19(12), 70 (1972)
Frenkel JJ, J. Phys., 9(5), 385 (1945)
Gibb WH, Powder Ind. Res., 1, 269 (1981)
Hein HK, "In Fouling and Slagging Resulting from Impurities in Combustion Gases," Engineering Foundation, Bryers, R.W., Ed., New York, 69 (1983)
Honea FI, "In Fouling and Slagging Resulting from Impurities in Combustion Gases," Engineering Foundation, Bryers, R.W., Ed., New York, 117 (1983)
Nicholls P, Selvig WA, "Clinker Formation as Related to the Fusibility of Coal Ash," U.S. Bureau of Mines Bulletin 364, Washington, U.S. Bureau of Mines (1932)
Raask E, "Mineral Impurities in Coal Combustion," Hemisphere Publishing Company, New York (1985)
Raask E, J. Therm. Anal., 16, 91 (1979) 
Reid WT, "Chemistry of Coal Utilization," Elliot, M.A., Ed., John Wiley, New York, Chapter 21 (1981)
Rindt DK, Jones ML, Schobert HH, "Investigations of the Mechanism of Ash Fouling of Minerals in Low-Rank Coal Combustion," Engineering Foundation Conference, Henniker, New Hampshire, July, 12 (1981)
Singer JG, "Combustion: Fossil Power Systems," Combustion Engineering, Windsor, CT, Chapter 3 (1981)
Smith EJD, J. Inst. Fuel, 29, 253 (1956)
Tangsathitkulchai M, "Studies of the Initiation, Growth, and Sintering in the Formation of Utility Boiler Deposits," Ph.D. Dissertation, The Pennsylvania State University (1986)