| Graphite tailings are a kind of solid waste produced in the process of graphite mine mining.If not properly treated,they will not only accumulate and occupy a large amount of land resources,but also cause serious ecological and environmental problems such as soil pollution.Reusing solid waste into building materials is a requirement for the healthy development of the economy and society in the new era,and has become a hot topic of current green research.This subject is based on solid waste treatment as a starting point to explore the feasibility of graphite tailings to replace part of cement mixed with mortar,and to provide certain reference value for its reuse research.To add a new material to cement,it must be clear whether it has pozzolanic activity.Therefore,in order to better evaluate the activity of graphite tailings,the activity of graphite tailings is first activated.This topic adopts the method of mechanical high temperature activation,that is,the method of mechanical grinding and calcination at high temperature,and the activation of the material X-ray diffraction analysis test,infrared spectroscopy and other methods,analysis and test of graphite tailings at 550℃,650℃,750℃,and clarified the change of activity with the increase of calcination temperature;through the strength evaluation method The thermal activation activity is designed with reasonable mixing ratio,and the variable is set as the content of graphite tailings,and the final compressive strength is used to optimize the content of graphite tailings.As a kind of electromagnetic wave,microwave can accelerate the curing of cement concrete and increase the strength in a short time.In order to better analyze the changes of electromagnetic field and temperature field during microwave heating,numerical calculation and finite element software are needed for simulation.Microwave heating is a two-way coupling process of electromagnetic field and heat transfer field.Therefore,it is necessary to study on the theoretical basis of the basic electromagnetic field equation Maxwell equation and heat transfer equation to derive the FDTD time domain finite difference equation and heat transfer equation in the time domain.solution.Based on the theory,the actual microwave oven is used as a model reference,the material parameters are set,the finite element grid is divided,and the physical interface is added to simulate the internal field distribution of the resonant cavity and the internal temperature change of the sample.The electrochemical workstation is used to continuously monitor the resistance of the cement mortar mixed with graphite tailings cured by microwave,and an equivalent circuit model is established to fit the resistance of different ages,and then the resistivity is calculated by the formula to obtain the resistance of the cement mortar mixed with graphite tailings The law of change of rate with time,combined with the results of compressive strength,the resistivity and compressive strength are used to jointly study the hydration process of the paste under the condition of microwave curing,and the resistivity-strength relationship model is established.Non-destructive testing provides new methods. |
