ABSTRACT
Referring to the physical properties such as Squarehole sieve allowance, ignition loss and others, the coal ash could be classified into three types, including I level, II level and III level ash according to the GB1596-91 standard. The physical properties and classification standard are shown in Table 1 and Table 2.[4-5]
Coal ash could be used for construction, backfilling, agriculture and producing building material, such as cement, brick, block, aerated concrete, ceramsite and etc. it also could applies for recycling to extract useful materials. Different usage has
1 INTRODUCTION
Coal ash is the inevitable output of thermal power. The coal ash emission amount around the world keep increasing year by year, but the utilization rate still maintains a low level. The developed countries, such as the United States and the Europe, have attached great importance to the comprehensive utilization of coal ash since 1960s. The applications become more and more extensive. The average utilization rate of the European coal combustion products association (ECOBA) member countries is about 48%. According to the American Coal Ash Association (ACAA) statistics, the utilization rate of coal ash in America rose from less than 20% in 1966 to 60% in 2007. Japan, as the world’s largest importer country of coal, with a small land and strict environmental demands, started research and industrialization early on coal ash. Nowadays the utilization rate has exceeded 85%[1-3]. In comparison, India’s annual coal ash emission was more than 100 million tons, but its utilization rate was less than 20%.
