Study On The Preparation Of Building Ceramic By Utilization Of Incineration Waste And The Solidfication Of Heavy Metal

At present in China, along with the great increase in municipal solid waste, construction of incineration plant is also increasing. Incineration technology has become the main municipal solid waste treatment technology that uses solid waste incineration to generate elecricity, thus coal consumption could be saved, but also achieve the purpose for volume reduction, elimination of hazards and resource utilization of so much MSW. But with the burning municipal solid waste treatment, it will produce ash and fly ash and other incineration residues, which will bring secondary pollution. Waste incineration residues contains many toxic heavy metals such as Pb, Cr, Cu, Zn, Ni, As and so on, if not treated directly use for landfills, heavy metals will leach of in natural environment because of the rain, which wil cause soil pollution. Meanwhile, the burning of waste also contains a certain amount of unburned organic matter, these organisms may cause harm to the environment.Therefore, how to treat with burning waste from power plants with harmless has become one of today's important issues. At present, many countries have researched on the handling of municipal solid waste ash, there are several major ways.Such as Cement solidification, melting solidification, pharmaceutical treatment, acid or other solution washing extraction treatment method. Cement solidification needs a large volume of cement and at the same time the heavy metals will leach out under certain conditions; melting solidification requires high temperature which would consume a large amount of energy, while high-temperature melting requires sophisticated equipment, thus increases economic costs; The stabilizer that use in pharmacy treatment is generally very expensive, therefore the costs of processing is high; while for the acid or other solution washing extraction treatment, process is complexity, more follow-up problems to deal with.Based on the analysis of the pollution and disposal for municipal solid waste, municipal solid waste ash is used as raw materials to appropriate a certain amount of kaolin and quartz to prepare the building ceramics in this paper. In this paper we realize the utilization of municipal solid waste incineration ash for the preparation of construction ceramics, while at the same time fix the heavy metals in the waste, reducing harm to the environment.The MSW incineration ash researched in this article comes from Xinxiang garbage incineration power plant located in a small Village of Changchun City. For the MSW incineration ash, the plant collects it respectively in the form of big gravel, small gravel, coarse ash and fine ash. Therefore, study on the four types of burning garbage separately in this paper.Use X-fluorescence to analyze the four residues of MSW incineration components, found that the four incineration residues are based on SiO2 and Al2O3 in the main.The content of SiO2 in large gravel and small gravel is above 60%, while the Al2O3 content is about 16%, and for the coarse ash and fine ash the content of SiO2 is 40%, Al2O3 is between 13% and 15%, while the burning garbage also contains a small amount of potassium, sodium, calcium and magnesium and iron oxides.For the coarse ash and fine ash, Pb, Cu, Zn were higher than the national standard, while for large gravel and small gravel in which the As content does not meet the national standard. Meanwhile, use XRD and FTIR to analyze the phase in the MSW incineration ash, the phase composition of MSW incineration ash is quartz, calcite and a small amount of high-temperature sanidine, most of the remaining is amorphous material. By the composition analysis of MSW incineration ash, we can see that the ingredients of MSW incineration ash is similar to the raw materials of ceramics, which can be used as raw materials for preparation of ceramic.To produce the ceramic, use bi-direction pressure, dry compression forming and low temperature fast firing porcelain. The water absorption and porosity, shrinkage and bending strength of the ceramic were tested, using the horizontal oscillation for heavy metals leaching toxicity of the ceramic, using XRD and SEM to analyze the mechanism for the solidfication of the heavy metal and the chinaprocess. Furthermore, the milling time of the raw materials, ceramic formulation, sintering temperature and holding time conditions were also studied, and at the same time researched the factors thet affects the performance of the ceramic.The optimum conditions for preparation of ceramics:the milling time for MSW incineration ash is 1.5h, molding pressure for the claybody is 9Mpa, the sintering temperature of fly ash is between 1150-1180℃, bottom ash sintering temperature is between 1170-1190℃, the insulation time is 1.5-2h.The mechanical property of the ceramic was tested, using the testing machine.The flexural strength of the ceramic is 62-110Mpa, the water absorption is 0.0047-5.224%, the porosity is 0.011%-8.04% and the shrinkage rate is between 15.6% and 32.46%. Heavy metal toxicity test result is as follows, Pb can not be detected, Cr and As is a few tenths of one ppb, Cu and Ni is a few ppb, while Zn has dozens of ppb, which is far less than the leaching concentration of national identification standard for leaching toxicity.XRD test of the ceramic showed that the crystal phase of the ceramic is anorthite and quartz for which the fly ash is the main raw materials, and the ceramic with bottom ash as raw material, the main crystal phase is mullite and quartz, other is mainly amorphous glass phase. Through the ceramic cross section SEM it can be seen that it has good grain morphology.By XRD and SEM test and analysis of solidfication of heavy metal, known that the mechanism of ceramic solidification of heavy metal is that the heavy metal can be in the form of glass inclusion solidified in the network structure of glass phase.Through the experiment, the ceramic with better performance has been made, and meanwhile realize the purpose for the solidfication of the heavy metal. The ceramic prepared in this paper can be used to substitute some of the marble used in construction marerial, for the burning of garbage harmless disposal and resource utilization found a new way.