| dc.description.abstract | In response to the demand of boilers to reduce coal combustion, the use of waste reuse fuels as boiler auxiliary fuel or biotear and coal combustion has gradually become an international trend.This study is aimed at substituting boiler auxiliary fuel for part of the co-fired fly ash produced by burning coal.However, the domestic has not yet fully standardized to solve the accumulation problem, so the basic physical and chemical properties of its materials have been explored and the feasibility of the reuse of co-fired fly ash resources has been evaluated. According to the cooperative boiler industry, the circulating and bubbling fluidized bed boilers are used, and the waste reuse fuels are RDF-5, waste wood, SRF and textile sludge. After individual co-firing with coal, this study is aimed at four types of co-firing ashes are mixed-fired RDF fly ash, mixed-fired waste wood fly ash, mixed-fired SRF fly ash, and mixed-fired textile sludge fly ash.
The chemical composition analysis shows that the chemical composition of the four mixed-fired fly ash is very different, among them, mixed-fired of RDF fly ash and mixed-fired of textile sludge fly ash with the highest calcium oxide content, while mixed-fired of waste wood and SRF fly ash are mainly silica, aluminum trioxide content; The ignition loss of mixed-fired fly ash is generally high, of which three kinds of mixed-fired fly ash exceed 20%. In terms of fineness, the results of the wet sieve test show that the sieve margin of mixed-fired fly ash flying ash is between 89% and 11%, which shows that the fineness varies greatly between various mixed-fired fly ash. Mixed-fired fly ash instead of 20% cement weight made of cement fly ash mortar, strength activity index in 7 days mixed-fired of waste wood fly ash and mixed-fired of SRF fly ash are 83.6% and 81.9%, respectively, showing that the two have the potential as supplementary cementitious materials(SCM).
Because the physical properties, chemical properties and composition analysis of the mixed-fired textile sludge fly ash are relatively stable with the cement mortar test, it is mainly used as a concrete additive and auxiliary cementing material for subsequent reuse tests.According to the basic properties of mixed-fired fly ash, it is applied to the design of high-pressure concrete floor tiles and permeable concrete mix design. To mixed-fired fly ash instead of 20% fine aggregate to make concrete bricks, in 28 days pressure strength up to A-class brick standards, it can be seen that mixed-fired fly ash can be applied to the production of nonstructural concrete products raw materials.Permeable concrete is reference ACI 522R for related tests, porosity between 18.1% to 24.3%, mixed-fired of textile sludge fly ash as cementitious material to replace part of the cement 20% or 10% weight, mixed-fired of waste wood fly ash is added to replace part of the cement 20% or 10% weight, mixed-fired of textile sludge fly ash 7 days and 28 days of pressure strength are higher than the design strength of 176kgf/cm2, the permeability coefficient for 28 days is 0.01m/s.
In summary the results of the test, the mixed-fired fly ash of this research material,with high loss on ignition or fineness of adverse characteristics, only a few mixed-fired fly ash has the feasibility of reuse as an supplementary cementitious materials, at the same time, because of the large variation of the mixed-fired fly ash material, it is necessary to carefully assess whether the source and material characteristics of the mixed-fired fly ash meet the engineering needs. | en_US |