| With the development of the times,the improvement of people’s lives,the city generated more and more garbage,the municipal solid waste incineration is the main way to deal with domestic waste,but the municipal solid waste incineration fly ash contains toxic and harmful heavy metals If handled properly,it will cause serious environmental pollution,but also a threat to people’s lives and health.This paper takes the municipal solid waste incineration fly ash produced by a waste incineration plant in Chongqing as the research object.The basic characteristics of municipal solid waste incineration fly ash,including physical properties and chemical leaching toxicity,were analyzed in laboratory.The main elements of incineration fly ash are O,Ca,Cl,K,S,and Na,which are the main elements of incineration fly ash by using XRF.The main heavy metal elements are Cu,Zn,Cd and Pb,and fly ash contains potential active substances such as CaO,Si O2 and Al2O3.SEM analysis shows that the surface of the MSW incineration fly ash is irregular and irregular,many.The leaching toxicity of heavy metal Cu was 17.605mg/L,the leaching toxicity of heavy metal Zn was 22.518 mg/L,the leaching toxicity of heavy metal Cd was 3.241 mg/L,and the leaching toxicity of heavy metal Pb was 18.107 mg /L.alkali-activators/fly ashes(A/M)(14.2%,11.1%,9.1%),Na2SiO3/NaOH(6/4,1/1,7/3)and liquid/solid(L/S)(0.43,0.45,0.47)were selected.L9(34),designed three factors three levels of experiments.The results showed that the best leaching toxicity rates of Cu,Zn,Cd and Pb were 86.96%,22.35%,61.31% and 64.91%,respectively.Considering the leaching toxicity of Cu,Zn,Cd and Pb,the optimum parameters were as follows: A/M was 11.1%,Na2SiO3/NaOH was 7/3,L/S ratio was 0.43.SEM analysis showed that the solidified body was compact and the compact state was intact.The FTIR analysis indicated that the heavy metal ions in the solidified body might be involved in the solidified body.Hydration,directly involved in the charge balance,heavy metal ions to Si-Al combination was reorganized,so that it is fixed in the structural system.On the basis of the best combination of orthogonal experiments,the stabilizer sodium sulfide,sodium phosphate and EDTA-2Na were used to carry out experiments with single stabilizer and compound stabilizer respectively.The results showed that the single stabilizer could achieve good effect,and Organic stabilizer EDTA-2Na effect is better than inorganic stabilizer sodium sulfide and sodium phosphate,taking into account the EDTA-2Na is expensive,there will be stabilizer and inorganic stabilizer combination,experiments show that sodium sulfide: sodium phosphate: EDTA-2Na 4: 1: 2 when the best curing effect of heavy metals.In the orthogonal experiment on the basis of the best combination of 10%~90% of the slag,from the experimental results,when the slag content of 60% and above when the concentration of heavy metal leaching concentration can be lower than the national standard " Landfill pollution control standards " GB16889-2008 in the provisions of the concentration. |
