Research On The Composite Activity Technique Of Coal Gangue

As one of the largest residue, coal gangue is the waste produced by coal mining. In China, the total amount of coal waste has reached 30 billion tones. These coal gangue not only occupies large amount of farmland,destroys environmental conditions, but also causes the atmosphere, soil, water pollution and geological disasters. However, from the view of environmental resources, coal gangue is a kind of metallic mineral resources which isconsisted of rock and mineral. Mainly based on the resource utilization of this industrial wasteresidue, the comprehensive utilization of coal gangue has become important research topics in the world. In China, although some progress in the comprehensive utilization of coal gangue has been made, the overall depth is still underdeveloped. There is much room for development in this area of research.In this article, the composition and structure of the coal gangue which come from Tong Chuan are analysis. The activity of the coal gangue is stimulated. The relationship between its structure and activity is discussed and a appropriate method about coal gangue as a supplementary gelatinize material is established. In this article, the main research content as follows:1. The chemical composition, mineral composition, crystal structure and physical characteristics of the original sample and treated samples are investigated by methods of chemical composition analysis, XRD, DTA and microstructure analysis.2. The coal gangue is activated by the pattern of mechanical - thermal complex activation .Its composition and structure are changed, and activity is produced. Some research such as the grinding coal gangue, calcinating in different conditions and macroscopic mechanical properties experiment have been done.3. According to experimental data, Some factors,which affect the volcanic activity of the coal gangue ,such as the coal gangue calcinated temperature, the grinding fineness, and the type of activating agent, dosage, application methods , are investigated. The best activation process and parameters are explored.Conclusions have been drawed through the analysis processing of experimental data: 1. Conclusion has been drawn by micro-analysis, XRD and DTA. The main reason for the activity of coal gangue is that the dehydration and decomposition of minerals and the ingredient of amorphous phase has been increased during the activation process of coal gangue.2. On the whole ,the optimum activation condition which enhance the strength and fluidness of cement mortar , reduce the water requirement of cement's normal consistency is as follows: calcining temperature at 625℃, grinding fineness of 2~# (The weight of 80um screen residue accounts for about 4.1 percent, The weight of 45um screen residue accounts for about 17.8 percent), the mixing amount of water glass as 2.5%, calcining time as 6 hours. Test technology of adding alkaline excitation agent before calcination is more superior.3. After composite activation, the coal gangue has good property of volcanic activity. The 28-day flexural strength of cement mortar which accounts for about 30 percent of the total quality of cement is very close to or even exceeds the strength of the reference cement. Contrasted with the enhancement on the compressive strength of cemen which was caused by activated coal gangue'effect, it's contribution to the flexural strength of cement is more visible.