Research On Producing Non-Fired Bricks By Red Mud And Fly Ash

Nowadays, with the development of alumina industry, the waste residues (red mud and fly ash) that are produced in that process have been taken for important contaminations. It is imperative to develope efficient disposal methods of red mud and fly ash andways of their economic utilization should, which is also important for the sustainable development of the industry of alumina. On the other hand, clay brick as one of the basic building materials is widely used in the industry and civil build. But the problem is that it destroys cultivatable infield, consumes reproducible powers, and pollutes the environment. Hence, it's exigent to exproe substitute for clay and new type of building materials. The non-fired bricks are made of red mud, fly ash from aluminum industry. And quicklime, gypsum, 32.5 ordinary cement is used as cementitious materials in the preparation in this article. On the basis of past research, the kind and the amount of raw materials, along with the parameter of molding are studied in view of capability and economy of the bricks. And also the front parameters mentioned are chosen in the light of the bricks composed characteristics. Based the results of previous experimentation, most of all the capabilities of the bricks are tested. The optimum properties can be obtained when non-fired bricks are produced by 25~40 percent of one year's red mud, 18~28 percent of dry fly ash, 30~35 percent of large size of slag in construction, 8~10 percent of quicklime, 2~3 percent of gypsum and 1 percent of 32.5 ordinary cement. After deposited in the range of 8 hours to 12 hours, the materials should be pressed less than 120 tons while their containing water ratio is from 15% to 17%. Under such conditions, the capabilities of the manufacture meet the standard of MU15. Minerals and microstructure of the bricks were invested with chemical analysis and XRD techniques. The reaction mechanism of the cementitious materials and the process of intensity forming are discussed on the basis of other's research. In addition, the economic of non-fired bricks produced by red mud and fly ash is analyzed, and the industrialization of that bricks is introduced. Finally, non-fired bricks made from red mud and fly ash have good prospect because of excellent properties, utilizing the waste residues of the alumina industry, simple productive technology and low cost. It has obvious economics, environment and social benefits, so this technology should be widely popularized quickly.