The invention relates to a method for preparing a lightweight
mullite refractory by high-
alumina fly ash and relates to the technical fields of
solid waste comprehensive utilization and refractories. According to the method, waste from a power
plant, namely high-
alumina fly ash, is used as a
raw material; commercial
alumina is added according to the composition design; the mixture is fired and crushed to prepare lightweight
mullite aggregate and lightweight
fine powder, with different granularities; then
silicon dioxide
fine powder is additionally added;
polystyrene spheres or
sawdust is used as a pore-forming agent,
aluminate cement is used as a gelling agent, and
sodium hexametaphosphate is used as a
water reducer; the lightweight
mullite refractory is prepared through the processes such as forming by vibration pouring, curing,
drying and
sintering. The main high-temperature-resistant phase of the lightweight
refractory is mullite phase and
corundum phase; the lightweight mullite refractory comprises the main
chemical constituents: 55.0-70.0 wt% of Al2O3, 25.0-40.0 wt% of SiO2 and 0-5.0 wt% of other impurities. Compared with the prior art, the method has the characteristics of wide
raw material source, low production cost, low
energy consumption, high mullite content, high performance, long service life, and simple operation in the preparation process; significant economic and environmental benefits can be generated.