Analysis Of Fly ASH Characteristics And Evaluation On Its Recycling Utilization

China is rich in coal, lack of petroleum and natural gas. For a long time, coal, which is the main energy resources, is the basic raw material for thermal power and heat supplier for many industries. The major solid waste from coal combustion is fly ash. Generally,4kg coal for combustion can cause nearly lkg fly ash. It is recorded in data that in2009the fly ash emissions in China was4.5X1011kg. In addition, adding the amount piled over the years, its quantity is extremely large. Provided an unreasonable treatment and disposal could not be carried out, there would not only occupy the land resources, but also be an impact on the environment.To implement sustainable development strategy and circular economy, through the pattern of "resources—products—wastes—cycling products" to fulfill a maximum profit of economy, environment and society with a minimum cost, and to build a environment friendly society are all the challenges China will face for a long time. It is significant for fitting on requirements of building environment friendly and resources saving society to increase the research on cycling utilization of solid wastes from fly ash industries.In this thesis, firstly there is a general introduction of fly ash cycling utilization in domestic and overseas. With the development of society, there is a much wider scope for fly ash cycling utilization and its main use areas are producing building materials. The solid wastes producing situation in Ningdong Energy (Coal) Chemistry Base in Ningxia province was taken as an example, and then choose the fly ash with large emissions as samples to conduct a characteristics analysis which included its chemical component, physical property and micro structure and component of particles, and based on these results to provide a foundation for fly ash cycling utilization. Aims at resolving the problems in fly ash firing bricks, choose the collected fly ash to test and analyze effect of different process parameters on bricks property, and optimize its producing process for saving energy and resources. Here comes a conclusion that through minishing diameter of fly ash particles and using suitable binder, the sintering process can be optimized and the blanks will have a enough plasticity. On the one hand, it can increase the content of fly ash and fully use the unburnt coal in it to turn the wastes into resources and protect the environment; on the other hand, minish the fineness degree of fly ash can increase its specific surface area, chemical activity and calcination rate, while the sintering temperature went down to save the energy. In line with the different fly ash adding content, choosing a suitable heat preservation time can both guarantee the production quality and save energy.And then, analytic hierarchy process and fuzzy comprehensive evaluation method were used to comprehensively evaluate the fly ash cycling utilization project, and analyzed the evaluation results. It is concluded that on the view of the first-class index, based on economic efficiency index, enterprise2has got the highest comprehensive evaluation score; based on environmental efficiency index, there was no big distinction among three enterprises; based on the social efficiency index, enterprise3has got the highest score. From the view of comprehensive enaluation system of fly ash cycling utilization, cement producing (for enterprise2) is the best way for its reusing, followed by the brick sintering (for enterprise3) and building blocks, ceramisite and ceramic sand producing (for enterprise1). According to the characteristics of each utilization ways and the specific circumstance in Ningdong Energy (Coal) Chemical Base, the beat way for fly ash recycling utilization was to produce sintering bricks, which was proposed based on experimentation and rooted in local conditions.