Experimental Study On Using Fly Ash In Power Plant As Compound Fertilizer

As a by-product of thermal power generation,fly ash is a rich potential resource and is now widely used in many industries.Among them,the use of fly ash to produce compound fertilizer is a technology that can both reduce the accumulated pollution and create a higher economic benefit.However,there are still many problems in the technology which restrict its development.In this paper,the physical and chemical properties of fly ash and fly ash compound fertilizer production process in-depth understanding of the development of the three parts of the study,to develop a no pollution of the environment,more economical and high efficiency fly ash compound fertilizer.The results show that the fly ash compound fertilizer produced by this method meets the requirements.The specific research process is as follows:The physical properties and XRF measurements of fly ash from four power plants and farming-derived yellow soil in the north of Baoding were carried out respectively.The results showed that the physical properties were better than that of yellow soil and both Chemical composition is more similar,some of the beneficial trace elements Cu,Zn,S and other content of fly ash even higher than the yellow soil,fertilizer conditions and potential.In the meantime,the leaching experiments of As,Cr,Cd,Pb and Hg,which are the focus of the five kinds of fly ash,were focused on.Based on the production mode and practical application of fly ash compound fertilizer,Fertilizer hardly affects soil heavy metal content.Iron is a necessary trace element for crop growth,and rich in iron content in fly ash,if you can leach more iron from fly ash for compound fertilizer,you can increase the fertilizer efficiency of fly ash at this stage.We designed a scheme to increase the leaching rate of iron in fly ash by calcining and acid leaching with addition ofNa₂CO₃in fly ash.First of all,the effect of mass ratio of fly ash to Na₂CO₃,calcination time and calcination temperature on the dissolution rate of iron in fly ash was determined by orthogonal experiment.It was concluded that the calcination temperature and calcination time had a great influence on the leaching rate.The mass ratio of coal ash and Na₂CO₃had little effect on the experiment.The calcination temperature was 800?,the calcination time was 2h,the mass ratio of fly ash to Na₂CO₃ was 1:1,and the leaching rate of iron was the highest,which was 15.19%.But at this time the dissolution rate is still small,so the subsequent acid leaching test,acid leaching each experiment with 20g of the mixed solid after calcination as a benchmark.The experimental results show that under the conditions of acid leaching time 2h and reaction temperature 80?,11mL of5mol/L sulfuric acid and then 0.96g of sulfamic acid are added dropwise.The dissolution rate of iron ions in fly ash reaches 91.40%Achieve the desired dissolution rate.As the fly ash into granular,loose texture,viscosity,so granulation process of compound fertilizer has brought great inconvenience.We propose innovative ideas,by extracting silica-alumina fly ash in the composition,modified into sodium silicate and aluminum salt,adjust the PH,the use of silicate and aluminum salt hydrolysis reaction jelly,improve Fly ash in the granulation of sticky problem.The experimental results show that the above-obtained aluminum sulfate crystals and sodium silicate crystals are respectively dried and pulverized,and then completely mixed at a molar ratio of 1:2.After the mixture is mixed with raw ash at a mass ratio of 1:9,Moisture,sodium silicate and aluminum sulfate occurred double hydrolysis reaction,resulting in a mixture of aluminum hydroxide and silicate jelly,with strong viscosity,the program feasible.In addition,the specific surface area of fly ash,strong adsorption,to be able to fix more fertilizer,improve fertilizer efficiency,but we are worried that the adsorption of fertilizer can not be successfully released,so the fly ash adsorption,filtration,titration and a series of experiment.The results show that the adsorption of fly ash basically does not affect the release of N,P,K.And microwave modification can increase the fly ash adsorption,let it fix more fertilizer,enhance this advantage.