The extraction and separation of residual carbon from coal gasification slag is the key to realize utilization of coal gasification slag.A large amount of carbon-ash complexes in the coal gasification slag formed under the conditions of high-temperature melting and complex reaction atmosphere.Grinding is an important method to dissociate the residual carbon in the slag.However,the particle size of the grinded slag is too small to use conventional separation process to extract carbon.Air classifier can achieve efficient separation of ul-trafine particles by utilizing the centrifugal force and aerodynamic drag of different particles in the vortex to generate different directions of movement for classification.Based on this,a dry carbon extraction process by grinding the gasification slag was proposed and then the air classifier was used to separate residual carbon and ash.Through the design of uniform test and the regression analyses of the influencing factors,the optimal experimental conditions were obtained and the experimental results were verified.The results show that the air-flow classification is influenced by the coupling effect of multiple factors,among which the frequency of the classifier and the frequency of the induced draft fan are the key factors affecting the carbon extraction effect,the optimum experimental conditions were the frequency of the classifier 175 Hz,the frequency of the induced draft fan 5 Hz,the frequency of the feed screw 5 Hz,and the opening of the secondary air valve 90°.The predicted value of the LOI of the carbon-rich products obtained under this condition(49.64%)is consistent with the experimental results(49.76%);Under the optimal conditions,the Dav of the carbon rich product obtained by airflow classification is 5.95 μm,can be used as a rubber reinforcement filler to replace carbon black and white carbon black;The calorific value is 16.73 MJ/kg,which can be fully used as fine powder fuel.Moreover,airflow classification can achieve good decarbonization effect of gasification slag,and the resul-ting decarburization slag has a loss on ignition of less than 10%,which is beneficial for its application in the field of building materials and other fields.The grinding crushing airflow classification method can achieve the separation of gasification slag,which is beneficial for its downstream utilization.
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