Analysis The Transferring Characteristics Of The Chlorine And Heavy Metals Of The Municipal Solid Waste Incinerator(MSWI) Fly Ash In Low & Medium Temperature Heat Treatment

As the blooming grows of the china's economy, the need of the energy is also keeping increase, then the number of the big/middle MSWI power plants is also taking on a increasing trend and the large mount of fly ash needed to be treated as well. The pollution problem of noxious and harmful substance contenting in the fly ash such as heave metals,dioxin becomes worse and worse., people have attached importance to the harmlessness of the fly ash yet.The thesis systematically study about the thermal treatment of the fly ash in the harmlessness technique of the MSWI fly ash. This study includes transferring characteristic of heavy metals in low temperature thermal treatment, transferring characteristic of chloride in low temperature thermal treatment, transferring characteristic of heavy metals in medium temperature thermal treatment, leaching ability of the residual after low temperature thermal treatment of MSWI fly ash. These foundational studies provide consults for the aftertime fly ash thermal treatment. Consequently, provide the way of finding a energy-saving/efficiency measure of thermal treatment to fly ash.Firstly, the nowadays status of municipal solid waste(MSW) and treatment of the MSW were introduced. Secondly, introduced the nowadays status of fly ash harmlessness technologies, and then discussed the property of the MSWI fly ash, again used the SOLAAR969 and 792 Basic IC for testing the heavy metals in the flow gas and fly ash and the chloride in the flow gas, than analysed their transferring characteristic.The thermodynamic stability of the heavy metals and chloride in the MSWI fly ash were studied on the test-bed in the lab, besides discussed the effects of different temperature and additives. The result indicated that, in the low temperature thermal treatment process, the heavy metals of the MSWI fly ash had a close transferring characteristic, generally speaking, when the temperature increasing the amount of the heavy metals also increased. Different heavy metals had different transferring characteristic. We can see from the result, the mount of the transferring heavy metals presented a Pd >Cr>Cd>Cu trend. In the medium temperature thermal treatment process, the amount of heavy metals in the MSWI fly ash also increased as the temperature increasing. The mount of the transferring heavy metals presented a Zn>Pd >Cu>Cr>Cd trend. Zn and Cu were hard volatilization heavy metals, they had a low amount of transferring, but when had a high thermal treatment temperature theirs transferring amount went up largely. For different additives, TiO2 had a catalysis property of Cd,Zn,Pb,Cu, it can increase the amount of the transferring heavy metals, but for CaO, it had a better solidify function.Through these experiments, we also studied the residua of the low temperature thermal treatment. The result indicated that, except Pb, other heavy metals studied were all lower than the national standard. Chinese national standard prescribed that if any heavy metals in the lixivium exceed the national standard, the waste was hazard waste. So after the low temperature thermal treatment the fly ash still was hazard waste, it can be used after stabilization treatment. For different additives, the CaO had a certain restrain function to heavy metals' leaching ability in fly ash, but TiO2 did not have this function.