Study on the preparation and properties of red mud unburned brick

AbstractIndustrial solid wastes such as red mud, fly ash as main raw materials. The unburned brick which mainly composed of red mud, fly ash was produced. The material composition and production technology have been studied. The results showed that the optimum properties can be obtained when unburned brick was produced by 44–55% 1 year's old red mud, 19–30% fly ash, 6–7% lime, 4–6% α-hemi hydrate gypsum, 25–35% Yellow River silt, 2% 42·5 ordinary cement. The best moulding process for the moulding pressure is 15 MPa, the optimum containing water ratio is from 14 to 18% and deposited in room for 12 hours, the compressive strength of the brick in the 28th day is up to 16·71 MPa. They satisfy the demand of MU15 high quality of fly ash brick. The phenomenon of re-alkali and radioactive was suppressed effective through the addition of appropriate amount additives, the comprehensive performance was superior.