Study On Characters Of Adsorption Nitrogen And Phosphorus Of Fly Ash In Different Deposited Conditions

With the development of coal electric industry, lots of thermal power projects are been investment and construction, and the amount of fly ash is piling up. Fly ash not only affected the environment seriously, but also leaded to increase the contradiction between people and land. The ecological reclamation of coal ash which has a good prospects can solve the contradiction and increasing the area of cultivated land effectively. But the reconstructing soil reclaimed by fly ash is not real soil, the adsorption ability of nutrient elements may be different from agricultural soils, and land reclamation project will be also affected by other factors.By taking Gaohuang ash field in Huainan as the research object, Four kinds of the nature status of fly ash samples which were in different deposited conditions were collected from Gaohuang ash field. Their particle size, water content, EC and pH value were measured. The adsorption kinetics and isothermal adsorption characteristics are analyzed. At last, the effect of reclamation on old ash field was evaluated by choosing an assessment evaluation system.Test results show:by measuring the physicochemical properties of samples, particle size of samples which were in the same depth was similar of sample similar to sample time stockpiling, between different pH value of samples which in different stockpiling time was also similar. It was found that soluble salt content in samples was little. The adsorption process was physical.Result of the adsorption kinetics experiments showed that, The equilibrium time of nitrogen adsorption was5h and the phosphorus adsorption’s was24h. In addition, First-order kinetic equation can describe the nitrogen and phosphorus adsorption kinetics process of fly ash samples; Difference analysis showed that the equilibrium time of four kinds of fly ash samples on adsorption nitrogen and phosphorus at room temperature was same, particle size and storage time influenced it less and the particle size result in the adsorption directly; The Langmuir isotherm adsorption model could describe four kinds of samples’adsorption characteristics better than the Freundlich isotherm adsorption model, and the sample which was deposited1 year in the surface layer had max theoretical saturation adsorption capacity; Difference analysis showed that, the particle size and EC affected the adsorption capacity.Data shows that fly ash has a water-holding capacity and supplying nutrient capability; The reclamation on old ash field effect was evaluated by using the reclamation quality system. Results showed the comprehensive index of reclamation was1.441which meant the reclamation on old ash field had a common effect. It is still need to be improved.