Study On Modification Of Shell Powder And Its Application

Now the world's attention is the question of environmental problems,including energy consumption,environmental pollution etc.In response to the strategy of sustainable development and for energy saving and environmental protection,reduce the waste of resources,the development of circular economy has become an important research direction.With the development of science and technology people gradually raise the living standards of people in the enjoyment of the progress of science and technology bring a better life has also been plagued by more and more solid waste.The resource recycling of solid waste has become a very important topic to explore.The huge production of solid waste shell sea area seriously affect the surrounding environment,with the environmental protection society gradually increased,the shell of solid waste resource utilization and development gradually to get everyone's attention.In this study,the waste oyster shell as the research object,the powder was modified by ball milling and calcining in two ways,changes of properties and structure of oyster shell powder each,and explore the changes between the performance and the change of parameters,to provide reference data for the future application research.Further the modified oyster shell powder should be used for non autoclaved insulation materials,reutilization of resources to achieve shell resources.The experimental results show that:Oyster shell powder in dry grinding process conditions reached 15h the aragonite CaCO₃ began to change to calcite type CaCO₃,The binding force of the group bond is also weakened,And the phenomenon of powder agglomeration is becoming more and more serious.Under the same ball milling time,Wet grinding and dry grinding method is modified by the oyster shell powder refining rate higher,But the main components and the CaCO₃ crystal type did not change during the wet milling process.Bond strength between groups was enhanced,and the powder did not happen.The optimum process of calcination and modification is:oyster shell powder particle size is less than 0.048mm,the calcination temperature is 1100 degrees C,and the calcination time is 150min.The modified oyster shell powder was used in the research of thermal insulation materials,and the two formulations were obtained.Formula one:dry grinding 10h oyster shell powder 15%,cement 53.33%,slag 22.95%,fly ash 9.5%,aluminum powder 2.14%.Formula Two:Calcined modified oyster shell powder 5%,cement 59.85%,slag 25.65%,fly ash 9.5%,aluminum powder 2.14%.The flexural strength of 7d and 18d of the products were 14 MPa and 16 MPa,respectively.The porosity and water absorption rate reach 65%and 20%,and the thermal conductivity is between W/m 0.043?0.048 and W/m·K.