| Municipal Solide Waste (MSW) problem has become one of the important social problems with urbanization, because more than 200 cities of china have been surrounded by MSW. Municipal Solide Waste Incinerrator (MSWI) is used widely to reduce volume and/or recover energy of MSW. After incineration, the incinerator residue and fly ash are about 20-30% of MSW. The fly ash belongs to hazardous waste and the incinerator residue is considered to be a non-hazardous waste. It is the intention of this work is that to use MSW incinerator residue make Incinerator Residue Non-burnt Wall Bricks (IRNWB) and to achieve waste resource utilization.On the basis of analyzing the composition and property of the incinerator residue from the Municipal solid waste incineration power plant of Li Keng in Guangzhou, the effect of different activators (Na2SiO3,Na2SO4,NaOH) on the properties of IRNWB were preliminarily investigated. The excitation mechanism of the Municipal Solid Waste Incinerator Residues (MSWIR) has been studied by XRD and SEM. The results showed that Na2SiO3 as activator and its content 5.5% are best.By using the orthogonal method with four factors (the molding pressure, pressure time, rati of pressure each section and pressure holding time) and three levels to design experiments, the influence of the four factors on the strength of IRNWB has been compared and the effect of the forming of water, environmental temperature, relative humidity and curing time on the properties of IRNWB has been studied. The experimental results showed that the optimum experimental program is A2B1C2D3, namely the molding pressure = 20MPa, pressure time = 60s, ratio of pressure each section = 3:1:1 and pressure holding time = 120s, and that the forming water about 10%, the suitable environment temperature 10℃~ 40℃, relative humidity 70% ~ 90% and suitable curing time 28d.The content of heavy metals,the leaching of heavy metals and heavy metals leaching toxicity limit in MSWIR are discussed. The results show that under acidic condition (pH = 3.2) the rate of heavy metal lixiviating is highest, followe it under the neutral condition and under pH = 5 condition the rate of heavy metal lixiviating is lowest. The fast heavy metal lixiviating presents to the first seven days, and the lixiviating amount of heavy metals accounts about 80%~90% of the total. Each cycle of heavy metal impregnation can meet the surface water standard of ClassⅡfor project C-1 and project C-10.Based on the test product and some reference data, the application of the Life Cycle Assessment (LCA) to IRNWB for project C-10,lime-sand brick and sintered brick is discussed. The results show that the environmental load of IRNWB,lime-sand brick and sintered brick is 3.51×10-12/a, 3.58×10-12/a and 6.6×10-12/a , respectively. 54% of non-producible resource depletion potential(compared with sintered brick), 43% of non-producible energy consumption ( compared with lime-sand brick ) and 62% of non-producible energy consumption(compared with sintered brick)can be reduced by comprehensive utilizing municipal solid waste incinerator residues to make unburned wall brick production.On the basis of project C-10,the feasibility of production line about 75 thousand cubic meters of the municipal solid waste incinerator residues non-burnt wall brick has been analyzed. The project construction investment is 5.662 million yuan and the project is the annual base rate of return 22.2%, which will realize profit by rough estimate. If processing Municipal Solid Waste Incinerator Residues can obtain subsidy about 40-60 yuan / t, this will be revenue,save large expenditure required for MSWIR landfill and have significant economic and social benefits.
|
PDF Full Text Request