INTERACTION OF MOLTEN SLAG WITH SOLID PHASE OF RED SLUDGE

Granulated blast furnace slag is steadily used in large quantities in production of cements, in road construction, agriculture and in other areas of engineering and technology. Peculiarity of its production process is active interaction of molten metallurgical slag with cooling liquid. Simultaneously and instantly, slag solidifies and the mass of the latter breaks up in the atmosphere of hot steam into small particles due to critical stresses occurring. The problem is that during granulation of slags, usually containing sulfur, large amount of harmful substances (sulfur oxide and hydrogen sulfde) is released into the atmosphere. Its concentration at work sites - sites of granulation many times exceeds the MPC. To combat this phenomenon, finely dispersed, expensive lime or limestone is introduced into the composition of cooling liquid. This is associated with high costs for the construction of crushing, grinding and dust treatment equipment. In addition, placement of such equipment is hampered by the lack of free space in the blast furnaces. In this work, it is shown that lime and limestone can be replaced by fine red mud (RM), a waste from the production of alumina from bauxite. This material also has properties of absorption of sulfur compounds from the gas phase. The problem of its processing is also an urgent task. At present, RM is located in sludge storage facilities that are harmful to environment, and destruction of the enclosing dam leads to an environmental catastrophe (Hungary, 2010). This article presents the results of study of RM use. Sorption properties of RM of 6 plants were studied under laboratory conditions. The samples of granulated slag obtained in the process of interaction with RM were investigated. Laboratory and industrial tests were conducted. It was found that with its help, concentration of sulfur gases at granulation work sites can be reduced by twice. It is important that the new granulated slag, called “sludge-slag” in this case, is not inferior to the usual one by its basic technological properties.

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