Influence of dolomite additive on the ash fusion and potassium fixation characteristics of rice straw

The influence of dolomite as an additive on the slagging and potassium fixation characteristics of rice straw upon burning was investigated in a tube furnace; the slagging mechanism as well as the interaction between the rice straw ash and dolomite were explored by using the inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray diffraction (XRD). The results show that the slagging characteristics of rice straw are significantly influenced by adding 5% dolomite. Dolomite can greatly improve the potassium fixation ability, especially at 900-1000℃; moreover, the Mg and Ca elements rich in dolomite can react with SiO₂ in the rice straw ash, forming high-melting silicate minerals including diopside, monticellite and merwinite.