Modification And Application Of MSMWI Fly Ash By Mechano-chemical Method

The municipal solid waste incineration fly ash is a by-product of waste incineration power generation,which contains many heavy metal elements and dioxin and other harmful substances,if not properly disposed,it will cause great harm to the environment and human health.If MSWI fly ash is used as plastic filler,wrapped in polymer matrix,so that the harmful substances are not exposed in the natural environment,and can be used in resource,and create economic benefits.However,fly ash powder has strong hydrophilicity and poor compatibility with polymer matrix,and it will be greatly restricted when used as filler.In this paper,the mechanochemical method is used to modify the MSWI fly ash and optimize the process parameters to improve the performance of the fly ash as filler.In this paper,a horizontal ball mill is used as a modification device,and the fly ash powder is modified by mechanochemical method,and study the modifier types and dosage,modification time,milling speed,ball to material ratio and so on process parameters on the modification effect.The results show that the quality of sodium stearate is 2wt%,the rotational speed of ball mill is 200rpm,the modification time is 150min,and the ball to material ratio 3:1 is the best technological parameter for fly ash modification.Under these conditions,the oil absorption value of modified fly ash sample was 28.2g/100g,the contact angle was 110.5 degree,and the modified sample had good hydrophobic lipophilicity.The modified fly ash samples were characterized by FT-IR Spectrometer.The results showed that the modified sodium stearate was successfully adsorbed on the surface of MSWI fly ash to prove the success of the modification effect.Moreover,the characterization of powder particle size shows that the addition of sodium stearate can help fly ash powder to be more fully broken and refined during ball milling.On the fly ash/calcium carbonate composite powder by mechanochemical method and dry modification experiments showed that the optimal modification conditions as modifier for sodium stearate in waste incineration,the amount of modifier for 2wt%,rotation speed 200rpm,modification time 150min,ratio of ball to powder 5:1.Under these conditions,the oil absorption value of the modified composite powder was reduced to 22.6g/100g,and the contact angle was 106 degrees.The particle size of the composite powders is more concentrated after ball milling modification.The filling of fly ash in polypropylene(PP)can effectively reduce the leaching of heavy metals in fly ash,the concentration of Cr6+ leaching from 2.85 μg/ml reduced to 0.05 μg/ml,to ensure the environmental safety of fly ash/PP composite materials.Fly ash/PP composites compared to pure PP,decreased the tensile strength,bending strength and impact strength with the increase of filling quantity increases first and then decreases,and the modified fly ash powder compared to the unmodified fly ash powder can have better compatibility with the PP matrix,The comprehensive mechanical properties of the composites are improved.