The effect of material formula of fly ash/sludge derived fuel on its melting characteristics
The material formula of Ash Sludge Derived Fuel(ASDF)derived from waste incinerator fly ash and sludge has a significant impact on its melting characteristics.The melting temperature of ASDF with different material formulas and additive conditions were studied.Furthermore,the mineral compositions during melting processes were analyzed with FactSage.It was shown that the melting temperature was influenced by the formula of ASDF due to its alkalinity and the synergistic effect between the components of ASDF at high temperature.The ash flow temperature is the lowest(1 150 ℃)when the ratio of fly ash,municipal sludg and coal equals 30∶30∶40.The co-melting between gehlenite(Ca2 Al2SiO7),andradite(Ca3 Fe2 Si3 O12),gematite(Fe2 O3)and okenite(Ca3 Si2 O7)occurs near 1 140 ℃ at this ratio.The addition of bentonite and borax to ASDF can reduce the melting temperature.With the ratio of 2％bentonite,the basicity of ASDF ash is close to 1 and the flow temperature reduces to 1 130 ℃.The melting temperature significantly decreases linearly with the increase of borax content in ASDF.Taking into account the potential impact of low ash melting temperature on slagging and ash agglomeration in the furnace,5％to 9％of borax addition was recommended to achieve complete ashing of ASDF and the ash flow temperature reduces to 1 039 ℃.
waste incinerator fly ashsludgeASDF(Ash Sludge Derived Fuel)ash melting temperature
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