Study On Preparation Of Self-cleaning Foamed Concrete Based On Domestic Waste Incinerator Slag

With the increase of population and the rapid development of social economy,the domestic waste increasing and properly handling domestic waste have become a global problem.At present,the most common method for handling domestic waste is landfill treatment,but landfill treatment occupies a large amount of valuable land resources,and a large amount of recyclable waste is landfilled.There are serious secondary pollution and the cost of post-management will continue to increase.The domestic waste incineration treatment has a significant reduction in capacity,reaching 80-90%.At the same time,it can not only make full use of the generated thermal energy to generate electricity,but also make resource utilization of the generated domestic waste incinerator slag,which is truly energy-efficient,completely harmless and resource-based treatment of domestic waste.Firstly,the basic physical,chemical properties and safety of domestic waste incinerator slag which is from Beijing Shougang Biomass Energy Technology Co.,Ltd.Lujiashan Waste Incineration Plant were studied.In terms of physical composition,the domestic waste incinerator slag is mainly composed of slag,ceramics,masonry,metal products,glass and a small amount of organic matter,and the hard slag has the largest proportion,reaching 64.07%.By XRD,XRF,SEM,TGA and pozzolanic activity analysis of slag,the main mineral composition of domestic waste incinerator slag is quartz,calcite,hydrocalumite and fayalite.The main chemical compositions are CaO,SiO₂,Al₂O₃ and Fe₂O₃,and like fly ash it belongs to the CaO-SiO₂-Al₂O₃-Fe₂O₃ system.The filling effect and morphological effect deviation of the domestic waste incinerator slag have thermal stability and do not have volcanic ash activity.The content of heavy metals Cd,Cu and Pb in the domestic waste incinerator slag has exceeded the class III soil standard and needs to be solidified,but the heavy metal leaching content is lower than the solid waste leaching toxicity identification standard.Secondly,the excitation effect of chemical activator on the domestic waste incinerator slag was studied.When single chemical activator was used,Ca?OH?₂ had the best excitation effect,followed by NaOH,and Na₂SiO₃.9H₂O was the worst.The best blend of Ca?OH?₂ is 3.5 wt.%.When Ca?OH?₂ and CaSO₄ were used to excite the domestic waste incinerator slag,the best excitation effect was obtained when the corresponding dosage of Ca?OH?2 and CaSO4 were 3.5wt.%and 1.0wt.%respectively.Then,the effect of sodium alginate solution dosage and temperature on the compressive strength of slag foam concrete was studied.The results show that when the temperature of sodium alginate solution is 60?and the dosage is 68%of the total water consumption,the prepared slag foamed concrete has the highest compressive strength of 4.29 MPa,and the compressive strength is increased by 94.12%compared with the blank sample.Finally,the photocatalyst TiO₂ was introduced to prepare slag-loaded TiO₂self-cleaning foamed concrete.The results show that the doping amount of TiO₂,porosity,dry density,surface porosity and pore microstructure determine the photocatalytic degradation properties of self-cleaning foamed concrete.Appropriate doping amount of TiO₂ can improve the photocatalytic performance of self-cleaning foamed concrete and slightly increase the compressive strength of foamed concrete.The photocatalytic degradation of methylene blue by self-cleaning foamed concrete with0.4wt.%TiO₂ is optimal.When the degradation time is 120min,the degradation rate can reach 99.96%.Figure[26] table[15] reference[51]...