Effects Of Treatment Of Raw Materials For Fired Thermal-insulating Blocks On Their Ageing Performance

As one of fired hollow products, fired blocks have the property of thermal insulation, and can be used as external thermal insulation materials of walls and roofs.The use of coal gangue and other solid waste to produce fired insulation block, both to protect the environment, but also to achieve good economic and social benefits. Good good economic and social benefits can be attained and enviroment can be protected by using coal gangue and other solid waste as raw materials of fired blocks. The optimized process parameters is basic of production of thermal insulated fired block. As an important part of production process, investigation on ageing has a certain practical significance. By studying the effects of aging process parameters on plasticity index of different materials, the paper evaluates the importance of the ageing process on thermal insulation blocks.In the present thesis, the chemical and mineral composition of coal gangue and shale were characterized, and drying sensitivity coefficient, critical moisture content,drying shrinkage and other physical properties of the raw materials, were tested and evaluated based on relevant standards. Also, the effects of raw materials species,moisture content, particle size distribution and aging temperature, aging time and other aging conditions on plasticity index were studied, and then the influence degree of the characteristics of raw materials and aging conditions on plasticity index were evaluated.The results show that the plasticity index of raw materials increases and the performance of the raw materials were improved after the ageing process at room temperature. The plasticity index increases rapidly in the first three days, and increases slowly since then, so the best ageing period should be three days. Plasticity index of rawmaterials increases with increasing of water content, when the water content in raw material approaches its liquid limit, pug becomes slurry. Combined with the production process, the optimal ageing moisture content of raw materials should be close to the molding moisture content, which meet not only moisture requirements of ageing, but also technical requirements. The plasticity index increases with decreasing of particle size, and the growth rate of plasticity index also increases. The better ageing performance can be obtained for smaller particle size of raw materials. Experimental results of plasticity index of raw materials at normal temperature, 30℃, 40℃, 45℃after one day ageing show that the plasticity index increases and ageing performance become better with rising of ageing temperature.