Study On Properties Of Light Soil Prepared From Waste Incinerator Slag Based Binder

At present,the treatment methods of domestic waste at home and abroad include landfill,incineration and composting.China mainly uses waste incineration for power generation to treat domestic waste.The remaining non combustible and unburned substances after waste incineration power generation and the bottom ash of incinerator slag such as slag,glass and ceramics.At present,the comprehensive application of bottom ash for incineration is mainly in the production of asphalt mixture,road aggregate and non fired brick,but the dosage is low,generally less than 20%,and there is little research on bottom ash less than 2mm.In view of the problem of low content of waste incineration bottom ash due to its low activity when used in the research and preparation of products in the past,this paper takes the fine bottom ash of municipal solid waste incineration（MSWI-BAF）made by grinding the domestic waste incineration bottom ash（<2mm）from Guangzhou Huadu waste incineration plant as the research object to explore the resource utilization mode of large amount of fine bottom ash of municipal solid waste incineration.The main research contents and conclusions are as follows:（1）The basic physicochemical characteristics of MSWI-BAF are studied by macro and micro tests.The research shows that MSWI-BAF has small particles,uniform particle size distribution,light weight,large specific surface area and true density,low water content,irregular particle shape,more internal pores and large interstices between particles.The chemical elements are mainly Ca O,Si O₂ and Al₂O₃.（2）Test the activity of mswi-baf,fix 50%of mswi-baf,add the composite material for excitation,explore the best mix proportion of mswi-baf based binder through mechanical property test,and demonstrate the hydration products after excitation through micro test analysis.The research shows that when the ratio of cement to slag powder is 1:1 and the ratio of anhydrous sodium sulfate and lime of the composite material is 3:1（s3c1）,the mechanical properties of mswi-baf based binder are the best,and the main hydration products are ettringite CSH gel and calcium hydroxide.（3）Mswi-baf based lightweight soil with 50%content is prepared by using the best mix proportion of mswi-baf based binder.The common macro properties are tested in the laboratory.The research shows that with the increase of bulk density of mswi-baf based lightweight soil,its compressive strength,fluidity and water stability coefficient at 7d and 28d increase,while the defoaming rate,slurry solidification settlement rate and water absorption decrease.Its fluidity increases with the increase of water binder ratio,and the compressive strength is the best when the water binder ratio is 0.7,Its 28d compressive strength can reach 2.63mpa,the defoaming rate with a unit weight of more than 550 kg/m3 is less than 10%,the maximum settlement rate is 1.94%,the mass water absorption and volume water absorption are between20%～53%and 14%～27%respectively,and the water absorption is large,but the water stability coefficients of 7D and 28d are more than 0.8 and 0.78 respectively,and the water stability performance is good.（4）The mechanical properties of mswi-baf based light soil are verified by X-ray diffraction phase analysis,scanning electron microscope test and thermogravimetric test,and its environmental protection is analyzed by leaching toxicity.The research shows that the hydration products of mswi-baf based light soil mainly include CSH gel,ettringite,calcium carbonate,partheite and calcium hydroxide.The formation of Ca CO₃ in the later stage further improves the compressive strength of mswi-baf based light soil,The leaching concentration of various heavy metals is far lower than gb5085 According to the limit value of 3-2007,the foam light soil containing a large amount of mswi-baf is harmless to the environment.