| With the improvement of living standards,human beings are increasingly mining mineral resources,resulting in an increasing output of tailings.The problem of environmental pollution is also becoming more and more serious,which has certain harm to human production and life.According to the composition and structural characteristics of the tailings,rational use of them can solve environmental pollution and bring certain economic benefits.In previous studies,some researchers successfully used ceramics such as bauxite tailings,iron tailings,and rare earth tailings to prepare ceramics.Some people also used silver mine tailings to prepare ceramsite,foam glass,and building mortar.However,there are few studies on the use of silver mine tailings to prepare ceramics.In this paper,three kinds of composite ceramics?cordierite-quartz,mullite-quartz and diopside-quartz?were prepared by using silver mine tailings as the main material and other auxiliary materials.According to the composition and structural characteristics of the silver mine tailings,reasonable ingredients were selected,and the ratio of raw materials was designed and calculated.The firing process of ceramics was designed according to the ratio of raw materials.The ceramics prepared were subjected to performance tests such as volume shrinkage,bulk density,water absorption,apparent porosity,flexural strength and thermal expansion coefficient.Ceramic formulations and sintering temperatures were preferred.At the same time,the ceramics were characterized by XRD,FT-IR and SEM.The effects of different ratios and sintering temperatures on the structure and properties of the composite ceramics were discussed as followed.1.Cordierite-quartz composite ceramics were prepared with silver tailings as the main material and a certain amount of talc and kaolin.According to the test results of ceramic properties,the optimal ratio of the best raw materials is 60%of silver mine tailings,26.88%of talc and 13.13%of kaolin.The optimum sintering temperature is 1250?.The thermal expansion coefficient of the ceramic obtained under this condition is 8.117×10-6/?,the flexural strength is 88.33 MPa,and the water absorption and apparent porosity are 2.29%and 4.73%respectively.Compared with the ceramic prepared by using 100%silver tail as raw material,the coefficient of thermal expansion is reduced from 20.639×10-6/? to 8.117×10-6/?,which greatly improves the thermal stability of the ceramic.Because the cordierite has excellent thermal stability and little expansion during its thermal process,the formation of the cordierite phase leads to a decrease in the coefficient of thermal expansion of the ceramic.2.Mullite-quartz composite ceramic was prepared with silver tailings as the main material and a certain amount of kaolin.According to the test results of ceramic properties,the optimal ratio of the raw materials is 70%of silver mine tailings and30%of kaolin.The optimum sintering temperature is 1350?.The flexural strength of the ceramic obtained under this condition is 94.41 MPa.The water absorption and apparent porosity are 3.04%and 6.08%respectively.The flexural strength of ceramics increased from 39.98 MPa to 94.41 MPa compared to ceramics obtained with pure tailings.This shows that the mullite phase in the ceramic enhances ceramic's mechanical properties.3.Diopside-quartz composite ceramics were prepared with silver tailings as the main material and a certain amount of talc and wollastonite.According to the test results of ceramic properties,the optimal ratio of the raw materials is 50%of silver tailings,26%of talc and 24%of wollastonite.The optimum sintering temperature is1250oC.The flexural strength of the ceramic obtained under this condition is72.00MPa,the water absorption and apparent porosity are 0.27%and 0.50%espectively.Compared with mullite-quartz multiphase ceramics,the addition of talc and wollastonite effectively reduces the ceramic forming temperature of diopside-quartz multiphase ceramics. |
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