MAGNESIUM ALUMINUM SPINEL BRICK PREPARATION METHOD AND MAGNESIUM ALUMINUM SPINEL BRICK PREPARED USING SAME

摘要

Disclosed are a method for preparing magnesium aluminum spinel bricks with a low thermal conductivity and magnesium aluminum spinel bricks with a low thermal conductivity prepared using same. The magnesium aluminum spinel brick is composed of a refractory layer and a thermal insulating layer, and the specific preparation steps are as follows: (1) preparation of raw material for the refractory layer: the content of each component is expressed in mass percentage, 40% to70% of sintered magnesia having a particle size of 5mm or less, 10% to 40% of fused magnesia having a particle size of 3mm or less, 10％ to 20% of magnesium aluminum spinel having a particle size of 4mm or less, and more than 0% to 10% or less of corundum having a particle size of 2mm or less are uniformly mixed to form a raw material mixed powder for the refractory layer, which is then uniformly mixed with 1% to 5% of naphthalene-based binder based on the total weight of the mixed powder for the refractory layer to prepare the raw material for the refractory layer; (2) preparation of raw material for the thermal insulating layer: the content of each component is expressed in mass percentage, 40% to 60% of forsterite, 10% to 40% of fayalite and 10% to 50% of magnesia are uniformly mixed to prepare a mixed powder, which is added with 1% to 5% of naphthalene-based binder based on the total weight of the mixed powder, molded using a friction press, dried at a temperature of 110 ° C to 150 ° C and sintered at a high temperature above 1000 ° C to obtain a composite aggregate hortonolite raw material; the composite aggregate hortonolite raw material having a particle size of 5mm or less, as a single raw material, is added with 1% to 5% of naphthalene-based binder, and uniformly mixed to prepare the raw material for the insulating layer; (3) the raw material for the refractory layer and the raw material for the thermal insulating layer are separated with a corrugated thin iron plate and put into a mold, pressed into green body using a press machine, dried at 110 ° C for 24 hours, and sintered in a tunnel kiln at a temperature of 1550 ° C to 1750 ° C to prepare the magnesium aluminum spinel brick, wherein the sequence of step (1) and step (2) can be interchanged. The magnesium aluminum spinel brick has a high purity magnesium aluminum spinel material refractory layer and a composite forsterite material thermal insulating layer, and the sintering temperature of the thermal insulating layer is improved to be matched with the refractory layer by adjusting the insulating layer formulation, while the consistency of the low thermal conductivity and the linear expansivity of the refractory layer and thermal insulating layer is ensured.