Light corundum-mullite refractory brick and preparation method thereof

Abstract

The invention relates to a light corundum-mullite refractory brick and a preparation method thereof. The preparation method comprises the steps of evenly dispersing 0.5-1wt% of silicon oxide micro powder and 2-4wt% of active alpha alumina micro powder in 5-8wt% of silica sol to obtain modified silica sol, placing 40-70wt% of porous corundum-mullite ceramic particles in a vacuum mixer, carrying out vacuum pumping until the vacuum is below 2.5 kPa, keeping the constant pressure for three minutes, then pouring the modified silica sol into the vacuum mixer, mixing for ten minutes and closing the vacuum pumping system, pouring 10-25wt% of porous corundum-mullite ceramic fine powder, 10-20wt% of corundum fine powder, 1.5-4wt% of silicon oxide micro powder and 1-3wt% of active alpha alumina micro powder into the vacuum mixer for mixing and mechanical pressing, drying and finally preserving heat at 1400-1600 DEG C for 2-10 hours. The prepared product has the characteristics of controllability in apparent porosity and pore size, low thermal conductivity, good thermal shock stability and strong medium erosion resistance.

Description

technical field [0001] The invention belongs to the technical field of lightweight refractory bricks. In particular, it relates to a lightweight corundum-mullite refractory brick and a preparation method thereof. Background technique [0002] Lightweight corundum-mullite refractories have low thermal conductivity and excellent high-temperature performance, and have been widely used as thermal insulation linings for high-temperature vessels. At present, the development of lightweight corundum-mullite refractories includes two aspects: [0003] (1) Lightweight corundum-mullite refractories with homogeneous structure. For example, use gel injection molding technology to prepare mullite-corundum lightweight bricks with high-alumina bauxite, silica fume and polystyrene ball pore-forming agents (Yang Daoyuan et al., High-strength and low-thermal conductivity mullite-corundum lightweight bricks Preparation of Rare Metal Materials and Engineering, 2009, 38 (2): 1237-1240), using ...

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Problems solved by technology

For example, heavy corundum-mullite materials, lightweight aggregates and powders are used as raw materials to prepare heavy working layer and light insulation layer composite bricks (a kind of corundum mullite structural heat insulation integrated composite brick and The preparation method (CN 201110150461.3)), although the thermal insulation performance is good, it is easy to cause cracks at the interface between the heavy layer and the light layer due to the thermal expansion mismatch and the influence of sintering, which affects the service life; another example is the use of porous corundum-mullite ceramics Preparation of lightweight porous aggregate aluminosilicate refractory bricks for aggregate (a kind of lightweight porous aggregate aluminosilicate refractory brick and its preparation method (CN200710052470.2)), although it has high strength, the porous aggregate There is no high-strength bridging between the interface with the matrix, and the pores at the interface between the porous aggregate and the matrix are in a continuous state, which cannot maximize the high-temperature strength and corrosion resistance; Balls are used as raw materials to prepare medium-density bricks (medium-density bricks for rotary kiln and its preparation method (CN201310029113.X)). Although the thermal conductivity is low and the thermal shock resistance is good, on the one hand, the hollow balls need to be melted and blown at high temperature. On the other hand, the surface of the hollow sphere is smooth and the compatibility with the matrix is ​​not good, which limits the high temperature performance