A silicon carbide-magnesium aluminum spinel-aluminum composite refractory material

Abstract

The invention belongs to the technical field of refractory materials, and relates to a silicon carbide-magnesium aluminum spinel-aluminum composite refractory material. A silicon carbide-magnesium-aluminum spinel-aluminum composite refractory material involved includes aggregates and a matrix; the aggregates are silicon carbide particles; the matrix contains aluminum-rich magnesium-aluminum spinel fine powder or micropowder; the matrix also adds The metal aluminum powder has been coated; the aggregate, matrix and binder are mixed uniformly, then machine-pressed, dried and fired at a maximum temperature of 1500 ° C to 1600 ° C in a carbon-buried atmosphere to obtain silicon carbide as the main crystal phase. Magnesia-alumina spinel and corundum as the subcrystalline silicon carbide-magnesia-alumina spinel composite refractory material. The invention reduces the difficulty of preserving the green body sample of the product, improves the high-temperature mechanical strength of the material, and simultaneously has the advantages of high thermal shock stability, good resistance to coal slag erosion, and low production cost.

Description

technical field [0001] The invention belongs to the technical field of refractory materials, and mainly relates to a silicon carbide-magnesium aluminum spinel-aluminum composite refractory material. Background technique [0002] The coal-water slurry gasifier is an important device in the field of coal gasification. It uses coal and water as the main raw materials to prepare gaseous H by burning coal-water slurry under high temperature and high pressure. 2 , CO, CO 2 Advanced equipment such as chemical raw materials. The operating conditions of the coal water slurry gasifier are: 1300℃~1500℃ high temperature, 2.0~8.5MPa high pressure and CO and H 2 The strong reducing atmosphere formed by such gases is accompanied by the scour and impact of high-speed air flow, slag and solid substances on the lining material during its operation. Under the high temperature environment and high furnace pressure, the continuous erosion of gas, liquid and solid phase substances will cause s...

AI Technical Summary

Problems solved by technology

The silicon carbide-magnesium aluminum spinel composite refractory material has excellent slag erosion resistance and permeability, but its high temperature mechanical properties are poor (the high temperature flexural strength is about 2-4MPa under the condition of buried carbon at 1400 ℃). In the high temperature and high pressure of the slurry gasifier and the continuous erosion of gas, liquid and solid, the material is prone to wear and peeling, and its excellent resistance to coal slag penetration and erosion cannot be reflected; the main reason for its low high temperature mechanical strength is : When fired in a carbon-buried atmosphere or a protective atmosphere, a small amount of oxidation of silicon carbide in the material will still occur, and the resulting SiO 2 Enter the matrix to form a low-melting glass phase. During high-temperature use, the glass phase changes from solid to liquid, which destroys the stability of the material matrix structure, resulting in its high-temperature mechanical strength far lower than the normal temperature mechanical strength; In addition, in silicon carbide -Metal aluminum powder is used as an antioxidant in magnesium aluminum spinel composite refractories. The chemical properties of metal aluminum powder are very active, and it can react with water vapor in the air at room temperature to form H 2 Escape and release a large amount of heat, thereby destroying the internal matrix structure of the material, increasing the difficulty of preserving the green sample, and greatly reducing its high-temperature mechanical strength