Experimental Study On The Preparation Of β-sialon By Using Coal Gangue Based On Combustion Synthesis Method

In this paper,the comprehensive utilization of coal gangue produced in coal mine production is used to prepare high performance materials.This method is not only in line with the development concept of low-carbon about environmental protection,but also to promote the transformation and upgrading of coal enterprises.In this paper,the waste coal gangue is used as the main raw material to prepare high performance β-Sialon.Sialon has good performances at different conditions of the material with excellent high temperature stability,corrosion resistance and low density.This material is widely used in automobile and aerospace industry,but also as corundum,SiC and other refractory materials supplement.On the other hand,Sialon Technology(combustion synthesis)has the characteristics of energy saving,environmental protection and simple steps.It is one of the most advanced technical methods for the efficient synthesis.Compared with the traditional Sialon powder preparation method such as the carbon thermal reduction method,combustion synthesis method has advantages of energy saving,environmental protection,quick reaction,low cost and convenient operation,and the product powder is not easy to sinter.First,we use the high temperature to remove volatile impurities.The reactor system thermodynamic theory is analyzed.On the basis of Gibbs free energy,β-Sialon synthesis thoroughly temperature of 2918 K has been calculated.Set different experimental system.This paper studied the Si powder on the combustion synthesis of β-Sialon,the Al effect on the β-Sialon combustion synthesis,the Si3N4 effect on β-Sialon combustion synthesis,the AlN powder effect of β-Sialon combustion synthesis and the mix parameters optimization effect of combustion synthesis on β-Sialon.The results of the study show that in the nitriding pressure 1.5MPa reducing agent used Al powder,added Si3N4 powder and AlN as raw materials according to the ratio of the chemical reaction equations and the amount of additive,the synthesis of Sialon was with high yield.XRD component was tested for the synthesis of different products in the reaction system by optical microscope,and SEM method has been in-depth analyzed the microscopic structure of each reaction system with the better experimental reaction process of continuous improvement.Six prismatic crystals in the production of β-Sialon were increased gradually.The combustion synthesis utilization of coal gangue as a product of grain the reaction raw materials prepared was fully developed.In this paper,the growth mechanism of β-Sialon was analyzed by means of SEM,and the physical model of VLS was established.In this paper,the combustion synthesis reactor system was used to produce the product,Al powder was used as a strong reducing agent,and Si3N4 and AlN were added in the experiment.These materials of the reaction system and group process-reaction phase were used to analyze the micro-structure in the constant tests and improving program.This paper has explored the ideal experimental of combustion synthesis conditions of producing Sialon: 1.5MPa nitrogen gas,using the coal gangue powder and Si3N4 by chemical reaction ratio,adding amount of Al powder which is 1.8 times of the coal gangue powder chemical reaction equation,adding the molar ratio of 5% weight AlN mixture for coal gangue.The diffraction peak intensity was the optimal scheme in single phase Sialon,optimal crystal phase impurity peak is very few,and it is showed high generation rate in XRD analysis.