Alumina-coated spinel-silicon carbide refractory composition with high corrosion resistance to coal slag and method for manufacturing the same

A method of manufacturing a spinel-SiC refractory composition, comprising:

• i) adding aqueous alumina sol to spinel aggregates to wet the spinel aggregates;
• ii) adding fine alpha-alumina and boehmite to the wetted spinel aggregates and mix thoroughly to get a spinel aggregate slurry;
• iii) drying and heating the spinel aggregate slurry to produce alumina-coated spinel aggregates;
• iv) sieving the alumina-coated spinel aggregates to remove loose alumina powder;
• v) preparing a refractory mixture by mixing together the sieved alumina-coated spinel aggregates, silicon carbide, alpha-alumina, and a dispersant;
• vi) adding the aqueous alumina sol to the refractory mixture from v) to form an unshaped slurry;
• vii) molding the unshaped slurry into a molded body;
• and
• viii) drying and sintering the molded body to manufacture the spinel-SiC refractory composition.