The invention relates to the field of
refractory materials, and discloses a high-purity
alumina lightweight aggregate and a preparation method thereof. The aggregate is prepared from
alumina micro
powder with a specific
particle size ratio: 50-60 wt% of micro
powder with the particle size of 70-115 [mu] m, 20-30 wt% of micro
powder with the particle size of 20-36 [mu] m and 10-20 wt% of micro powder with the particle size of 2.5-5 [mu] m, and each micro powder needs to meet the conditions that the content of alpha-Al2O3 is greater than or equal to 99.6% and the content of Na2O is less than or During preparation, water, the
foaming agent, the foam stabilizer, the binding agent, the dispersing agent and the
sintering aid are added in an external addition form, and the preparation method comprises the steps of mixing, pulping, foaming, foam stabilizing, pouring,
drying, high-temperature
sintering and the like. A foaming method is adopted to replace a traditional high-energy-consumption electric melting process, the
sintering temperature is reduced to 1600-1700 DEG C, and the
energy consumption is reduced by 30% or above. The obtained aggregate has high purity (Al2O3 is greater than 99.4 wt%),
low volume density (1.5-2.0 g / cm < 3 >), high apparent
porosity (50-70%), excellent normal-temperature
compressive strength (20-30 MPa) and low
thermal conductivity (0.3-0.7 W / (m.K) at 1000 DEG C), perfectly solves the problem that light weight, high strength and efficient
thermal insulation performance are difficult to consider at the same time, and is suitable for producing working lining and
thermal insulation layer products of high-temperature industrial kilns.