Plugging brick for top opening of water-coal slurry gasification furnace and preparation process thereof

The invention relates to a plugging brick for the top opening of a water-coal slurry gasification furnace and a preparation process thereof. The plugging brick comprises 60-70% of 0-5-millimeter particles of fused chromium oxide, 10-20% of 180-mesh fine powder of fused chromium oxide, 8-13% of 200-mesh chromium oxide green, 1-8% of 200-mesh fine powder of zirconium oxide and 3-8% of 1,000-mesh micro powder of active alpha-alumina, and the plugging brick further comprises 1-2% of micro powder of active rho-alumina, 0.15-0.25% of a compound additive in which the ratio of calcium lignosulphonate to polycarboxylic acid is 1:2 and 3-4% of solution of aluminium dihydrogen phosphate, wherein the specific surface area of the micro powder of active rho-alumina is 200m /g, and the specific gravity of the solution of aluminium dihydrogen phosphate is more than or equal to 1.85. The preparation process of the plugging brick comprises the following steps: premixing fine powder, mixing aggregates, ageing, molding, drying, sintering, assembling and processing. The plugging brick has high compressive strength and excellent corrosion and erosion resistance, is reusable, basically has the same volume as a plugging brick which has a high content of chromium of 90% and is used for the top opening of a water-coal slurry gasification furnace and is beneficial to prolonging the service life of the top opening of a water-coal slurry gasification furnace and keeping the top opening of a water-coal slurry gasification furnace intact.