Study On Purification Of Domestic Waste Incineration Bottomash And Test Of Non-burning Environmentally Friendly Building Blocks

With the continuous popularization of waste incineration power generation technology,the output of bottom ash has continued to increase.In order to make full use of the bottom ash into waste,a comprehensive understanding of its physical and chemical properties has been carried out.The bottom ash without any treatment is complex in composition,has a pungent odor,and contains some toxic heavy metal elements.It will bring great harm to the ecological environment without taking necessary harmless treatment.The composition and engineering properties of the bottom ash have significant similarities with natural sandstone.The content of SiO₂ is basically maintained at about30%,which limits the application range of the bottom ash in engineering,and the optimization of purification process can enhance the utilization value of industrial waste of bottom ash.Comprehensively consider the purification effect and economic cost,the"washing-pickling-roasting"process is used to prepare the purified bottom ash.The purified bottom ash and the pretreated bottom ash are used as raw materials,supplemented with cement,sand and additive to pressurize unburned blocks.When the particle size of the purified bottom ash is less than 74μm,the effects of raw material ratio,water-to-binder ratio and curing conditions on the mechanical properties of the unburned block were analyzed.Moreover,the reaction mechanism of unburned blocks were further discussed.The results showed that:feldspar are reduced,and organic carbon are decomposed,forming a higher internal amorphous structure.C-S-H gel of unburned blocks and hydration products were mixed and polymerized,forming compact structure with high mechanical properties.Under the existing technical conditions of the laboratory,the purified bottom ash and the pretreated bottom ash accounted for 60%of the total material,the optimization process conditions of unburned blocks were 14 h steam curing at 105℃as well as 0.2 water-to-binder ratio.The performance standards were in accordance with the requirements of“non-sintered waste tailing brick”MU20.The purified bottom ash and the solidification of the cement greatly reduce the heavy metal leaching content of the block system.Compared with the bottom ash raw materials,it will not cause pollution to the soil and groundwater environment.The effects of different rice hull ash（R-RHA,RP-RHA,PR-RHA）on the performance of bottom ash-based blocks were studied,and the corresponding mechanism was analyzed also.The results indicate that under the standard curing,the incorporation of rice hull ash decreases the compressive strength of bottom ash-based blocks at early age,but increases the compressive strength at later age,reaching the highest value with the species of PR-RHA;rice husk ash increases the resistance to carbonation of bottom ash-based blocks,and the improvement is best with the species of PR-RHA;rice husk ash improves the chloride ion penetration resistance of the bottom ash-based block,and its improvement effect is better with the change of its type R,RP and PR;rice husk ash improves the wear resistance of the block,but the difference in species does not have a significant impact on it.Figure[39]table[19]reference[50]...