Study On The Preparation And High Temperature Resistance Of Alkali-activated Coal-based Synthetic Natural Gas Slag Geopolymer

Geopolymer is a new type of building cementing material with low energy consumption and no pollution.It has excellent properties such as early strength,fast hardening,corrosion resistance and high temperature resistance.However,the basic performance of geopolymer is greatly affected by the type and concentration of activator,preparation technology and curing mode,so it has not been widely applied.In this paper,CSNGS was used as raw material to prepare geopolymer.Considering the influence of sodium silicate modulus,activator dosage and water-cement ratio(mass ratio of water to residue powder)on CSNGS geopolymer,the test results show that: The compressive strength of the CSNGS geopolymer is the highest when the modulus of sodium silicate is 0.8,the dosage of activator is 22% and the water-cement ratio is 0.34.And the 28-day compressive strength can reach 41.6 MPa.X-ray diffraction(XRD),field emission scanning electron microscopy(SEM),Fourier transform infrared spectroscopy(FT-IR)and other microscopic tests were used to analyze the phase composition,microstructure and chemical bonds of geopolymers.The test results showed that: With the decrease of the modulus of sodium silicate,the intensity of crystal peak in XRD pattern gradually decreases,and the amorphous phase gradually increases.The distribution of gel on the SEM surface becomes more uniform and compact.The vibration of chemical bonds in the infrared spectrum also indicates that the number of gel phase gradually increases.With the increase of excitant content,the intensity of crystal peak in XRD pattern decreases first and then increases,and the gel on microscopic surface increases first and then decreases.Under the condition of optimal mix ratio,the influence of preparation process on CSNGS geopolymer was further explored.The test results show that when the aging time is 24 h,the stirring time is 4min,the curing temperature is 70℃,the curing time is 24 h,and the conservation mode is natural conservation,the compressive strength of the prepared CSNGS geopolymer is the maximum.Finally,the high temperature resistance of CSNGS geopolymer is studied experimentally.The study shows that: CSNGS geopolymer can maintain a certain compressive strength under high temperature calcination,can be used as refractory material,and when it reaches 800℃,CSNGS geopolymer has ceramic tendency.Through the microscopic test analysis,it is concluded that the gel in the geopolymer will decompose gradually and new crystals will be generated at the same time.