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 °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 °C. The high temperature decreased the content of K₂O from 63.03 to 35.71% to improve the fusion characteristics of bamboo ash. 700 °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 °C, which transformed to complex silicates, aluminosilicates, and phosphates above a temperature of 700 °C. The temperature ranges of the three main stages were 550-980, 980-1190, and 1190-1500 °C, corresponding to mass losses of 11.52, 6.13, and 17.17%, respectively.