Preparation And Mechanical Properties Of Graphite Tailings Porous Ceramic Materials

With the continual development of national economy,the consumption of graphite is being increased year after year during the recent years,the capacity of the graphite production companies has continuously expanded and a large number of graphite tailings are stockpiled,which has not only occupied a large quantity of land and threatened the environment,but also has the risk of hidden trouble.Therefore,how to improve the integrated utilization of graphite tailings has become the key of sustainable development in graphite industries.The porous ceramic material was prepared by using graphite tailings as the bone material of porous ceramic and the process of adding pore-forming agents in this paper.The influences of the multi-factors such as the particle size of graphite tailings,the category and capacity of pore-forming agents and adhesives,sintering temperatures,molding pressures and temperature preservation times etc on bending strength,apparent porosity,water absorption and volume density of porous ceramic material made by graphite tailings were investigated.The main research contents are as follows:1.Selection of particle size of graphite tailings and pore-forming agents.The influence of the particle size of the graphite tailings on the performances of the porous ceramic material made by the graphite tailings was investigated.Based on the selection requirement of the pore-forming agents,carbon powder,starch and calcium carbonate were selected as the three pore-forming agents.The influence of different adding quantity of the three pore-forming agents on the properties of the porous ceramic material was investigated by using TYA-100C Electro-hydraulic Bending Test Machine and the boiling method.The research results showed that,the best particle size distribution of the graphite tailings was 75?m-97?m;under the same conditions,the descending order of pore-forming properties of the three pore-forming agents was carbon powder,starch and calcium carbonate in turn,and that of their bending strength was calcium carbonate,starch and carbon powder in turn.Therefore,the carbon powder was ultimately selected as the pore-forming agent for the preparation of the porous ceramic material,its addition of mass fraction range of 15%-25%was suitable.2.Selection of adhesives.Based on the selection principles of adhesives,bentonite and kaolin were selected as the two adhesives,the influences of the adhesive mechanism with the two adhesives as well as their different adding quantity on the properties of the porous ceramic material were investigated by using TYA-100C Electro-hydraulic Bending Test Machine and the boiling method.The research results showed that,the properties of the porous ceramic material made of bentonite as the adhesive were better,therefore,bentonite was ultimately selected as the adhesive for the preparation of the porous ceramic material,its addition of mass fraction range of 4%-8%was suitable.3.Investigation on the influences of preparation process on the properties of the porous ceramic material.The porous ceramic material was prepared by using carbon powder as the pore-forming agent and bentonite as the binder.The influences of different sintering temperatures,temperature preservation times and molding pressures on the properties of the porous ceramic material were investgated by using TYA-100C Electro-hydraulic Bending Test Machine and the boiling method.The research results showed that,along with the increase of the sintering temperature,the molding pressure and the holding time,the bending strength and the volume density were increased while the apparent porosity and the water absorption were decreased,in which its singtering temperature range of 1050?-1150? was suitable,the best molding pressure was 9MPa and the holding time of 60 minutes was most suitable.4.Analyses of crystal phase compositions and microstructures of the porous ceramic material.The crystal phase compositions and microstructures of the porous ceramic material made by the graphite tailings were measured and analysed by using D/max-2200 XRD and VEGA 3 SBU SEM.The research results showed that,the main phases were quartz and mullite,and a small quantity of phases was anorthite and hematite.The analysis results of SEM micrographs showed that,the pores in the porous ceramic material were pientiful and had higher specific surface area whose distribution was even and the bore stuctures were connected.5.Investigation on the optimum prescriptions and technical parameters of the porous ceramic material as well as the relationship between its bending strength and apparent porosity.The properties of the porous ceramic material made by different singtering temperatures,and addition quantity of the carbon powder under the determined process conditions were investigated by using TYA-100C Electro-hydraulic Bending Test Machine and the boiling method.The research results showed that,the main influence factors of the properties of the porous ceramic material were firstly the capacity of pore-forming agents and the sintering temperature,and secondly the adding capacity of bentonite,the holding time,the molding pressure and the particle size distribution of the graphite tailings.The optimum prescriptions and technical parameters were respectively like that,the capacity of carbon powder was 20%,the sintering temperature was 1125?,the capacity of bentonite was 6%,the holding time was 60 minutes,the molding pressure wais 9MPa,the particle size distribution of the graphite tailings was 75?m-97?m,and the capacity of water was 13%.Under the experimental conditions,the porous ceramic material could be prepared by the apparent porosity of 48.15%,the water absorption of 39.89%and the voloume density of 1.16g/cm3,and the bending strength was 15.83MPa,its relationship between the bending strength and the apparent porosity was?=141.17exp(-0.046p).The research work and achievements in this paper can provide a new approach for the integrated utilization of graphite tailings,and effectively solve the problem of the lower utilization degree of graphite tailings,which will afford acomparatively reliable experiment evidence and technical foundations for the preparation of porous ceramic material made by graphite tailings.