Preparation Of Geopolymer From Inorganic Matter In Tailing Coal And Its Adsorption Properties For Pb(?)and Cu(?)

With the increase of raw coal volume in coal preparation plant year by year,a large amount of flotation tail coal is discharged,and a large amount of tail coal is accumulated,which not only occupies land,forms dust and pollutes air,but also harms water and soil by harmful components in minerals through infiltration,and also causes environmental hazards such as geological disasters.With the development of clean coal technology and the improvement of national environmental protection requirements,the comprehensive treatment and utilization of the remaining tail coal in coal preparation plant has become an important problem to be solved.However,in recent years,geopolymer,a new type of inorganic environmental friendly green cementitious material,has attracted more and more attention of scholars.It has been proved that geopolymer can be used for efficient adsorption of heavy metal ions.In this paper,tailings based geopolymer was prepared from flotation tailings by thermal activation alkali excitation.The effects of various preparation factors on the adsorption capacity of Pb(?)by tailing coal based geopolymer were investigated.The physicochemical properties of the tailing coal based geopolymer were characterized by SEM,XRD,FTIR and bet,and the adsorption behavior of heavy metal ions on the tailing coal based geopolymer was discussed.The results show that:(1)The optimum preparation conditions are SiO₂/Al₂O₃=3,Na₂O/SiO₂=0.35,H₂O/Na₂O=12,thermal activation temperature 800?,curing time 36 hours,curing temperature90?,and carbon content 0.The adsorption capacity of the geopolymer is 228.57 mg/g,which is much higher than that of the raw coal by 64.48 mg/g,which is 6 times of that of the raw coal.The adsorption properties of geopolymer prepared from flotation tailings,kaolin and quartz were studied.The order of maximum adsorption capacity for Pb(II)is:tailings>kaolin>quartz.(2)When the activation temperature is below 600?,the utilization rate of silicon and aluminum in the tailing coal is low When the temperature is above C,the tailings based geopolymer is completely transformed into amorphous material,and the silicon and aluminum elements are fully utilized.The flotation tailings are mainly composed of irregular particles with different particle sizes,and the surface of the tailings is adhered with many powdered particles.After the heat activation alkali activation method is adopted,the original tailings structure is disappeared,showing a coarse and loose gel shape.The temperature is800.The absorption peak at 1104 cm^-1belongs to the asymmetric stretching vibration of Al-O/Si-O,and the peak at 683 cm^-1belongs to the asymmetric stretching vibration of Al-O/si-o The absorption peaks of cm^-1and below are due to the symmetric stretching and bending vibration of TO(T=Si or Al)bonds in tetrahedron structure,which indicates the formation of geopolymer gels.The surface area of tailings based geopolymer is 9 times higher than that of raw coal.(3)The adsorption of Pb(II)by coal based geopolymer conforms to the pseudo second order kinetic model,the isothermal adsorption conforms to the Langmuir model,and the adsorption of Pb(II)by coal based geopolymer is endothermic spontaneous process;the adsorption of Cu(II)by coal based geopolymer conforms to the pseudo second order kinetic model,the isothermal adsorption conforms to the Langmuir model,and the adsorption of Cu(II)by coal based geopolymer is endothermic spontaneous process The hair process.