Research On Coal Gangue Activation And Its Activity Evaluation Method

Nowadays, the sustainable development of national economy has been restricted by the non-reproducing and exhausting of natural resources, so it is of crucial significant to recycle the industrial waste. Coal gangue is industrial solid residues which are discharged when coal is excavated and washed in the production of coal mine, and is one of the most industrial solid castoffs. In our country, annual discharge of coal gangue is nearly 100 million tons, and the gross amount reaches more than 3000 million tons, what's worse, the amount is increasing year by year. However, the recycling ratio of coal gangue is less than 20 percent because of the lack of the fundamental researches about their utilization which at present focuses mainly on directly taking advantage of this material in an extensive way. Therefore, the basic theory about the activation of coal gangue should be established by investigating activation ways of coal gangue and discussing the relationship between its internal structure and activation. Furthermore, an effective evaluation method of the activation of coal gangue should also be founded to offer application basis for the effective use of coal gangue. These researches are all useful for science and society development. Taking account of these thoughts, many progresses were obtained as follows.The natural characteristics of raw coal gangue were characterized by use of modern testing such as X-ray diffraction (XRD), infrared (IR) and petrographic analyses. The results indicated that kaolinite and a-quartz are the main mineral compositions, and some gypsum, calcite, hematite and coal are also present in the coal gangue produced from Zibo, Shandong province. The cement mixed with 30wt.% raw coal gangue presents poor mechanical strength and apparent properties.The excitation to the activation of coal gangue by serious methods such as heat activation, mechanical activation, chemical activation and complex activation were investigated. The results indicated that the mechanical strength of cement with coal gangue calcined at 500-900℃ was far higher than that of cement with raw coal gangue. The 3, 28 and 90d compressive strengths of the cement mixed with 30wt.% coal gangue calcined at 700℃ were 1.5, 6.3 and 24.5MPa respectively, which all were higher than those of cement only with raw coal gangue. The optimal calcining temperature of coal gangue for heat...