The Ash-Forming Element Migration and Mineral Transformation during the Bamboo Combustion Process

To investigate the effect of combustion temperatures on element transformation of ash, bamboo was fired using a muffle furnace at 550, 600, 700, 800, 900, and 1000 degrees C. Chemical compositions, micromorphology, and mineral and thermal behavior of ash were characterized. The main components included K2O, SiO2, P2O5, MgO, and CaO at a temperature of 550 degrees C. The high temperature decreased the content of K2O from 63.03 to 35.71% to improve the fusion characteristics of bamboo ash. 700 degrees C was a key temperature for designing a combustion system of bamboo, where bamboo ash had a maximum volatility. The mineral phases were chlorides, carbonates, and sulfates below a temperature of 700 degrees C, which transformed to complex silicates, aluminosilicates, and phosphates above a temperature of 700 degrees C. The temperature ranges of the three main stages were 550-980, 980-1190, and 1190-1500 degrees C, corresponding to mass losses of 11.52, 6.13, and 17.17%, respectively.