Mineralogical Study Of Graphite Tailing From Luobei,China And Its Application As Conductive Rubber Filler

Yunshan graphite ore is called“The first big mine in Asia”located in Luobei county,Heilongjiang province,China.A lot of tailings were left with a large-scale development of graphite resources.The tailings have occupied the land and polluted the environment.The research on recycling of the graphite tailings has a great significance.In this paper,a detailed mineralogical study of graphite tailings was carried out including chemical composition and mineral phases.Composite powders recycled from the graphite tailings were added into the rubber as fillers after grinding and modification.Rubber composites with good mechanical and electrical properties were prepared.Results of mineralogical study reveal that this graphite tailing is composed of quartz,feldspars(potassium feldspar and anorthite),sericite,calcite,hematite,tremolite,chlorite and a small amount of residue graphite.Sericite accounts for 7%of the tailing while graphite accounts for 2.5%.The content of two of them are very low,it is difficult to recycle them from the tailings directly.With the particle size decreasing,the graphite and mica are obviously enriched under 200 meshes.The main phases of composite powders recycled from tailings are graphite,mica,quartz and feldspars.Graphite normally renders an image of small sheet,whose content is up to61.01%.The type of mica is mainly of fine white mica(sericite)and mostly in the form of fine flake or elongation of thin sheet.The sizes of graphite and sericite are both concentrated within 50?m.The results of composite powders as rubber fillers show that rubbers filled by composite powders were reinforced in property.The tensile strength of rubbers is greatly increased with the decreasing size of composite powders,while conductivity of the rubbers was hardly changed.With composite powders in conjunction with the use of conductive carbon black,the tensile strength and electrical conductivity of the rubbers are significantly improved.The maximum tensile strength is increased by 47%compared to the maximum amount of a single-composite powder filled rubber.When the filling content of conductive carbon black is 10 phr and that of composite powders change from 30 to 40 phr,the volume resistivity of rubber had a sharp decline,reaching the minimum about 10~6?·cm(40 phr).When the filling content of conductive carbon black is 10 phr and that of composite powders is 30 phr,the performances of rubber are favorable such as the electrical conductivity,tensile strength,hardness and resistance to flexible performance.The rubber can be made into antistatic sealing ring,rubber hose and other antistatic products.All the results indicate composite powders recycled from graphite tailing can be applied effectively as filler in styrene butadiene rubber.It has great economic and environmental benefits.