Study On The Preparation Of Expandable Graphite By Electrochemical Method

Expandable graphite is a kind of functional material with excellent properties, which can be widely applied in the fields of seal, flame retardant, adsorption, conductivity and so on.The traditional chemical oxidation method has brought serious pollution to the environment.The general use of sulfuric acid as the reaction medium, the high sulfur content of expandable graphite greatly limits its application area.In this paper, an electrochemical reaction device designed for the preparation of expandable graphite, the function principle, the overall structure, the design thought and the main parameter setting of the reaction device are introduced in detail. The preparation of sulfur expandable graphite with fine natural graphite as raw material,the electrolyte was mainly composed of HClO4 and CH3 COOH. The electrolyte composition, electrolyte atio,current density, electrolytic temperature, electrolysis time and electrolyte concentration on the effect of expansion volume of expandable graphite was studied by single factor experiment and orthogonal experiment. Results show that when the mixture of HClO4 and CH3 COOH as electrolyte, V(HClO4) :V(CH3COOH)= 4:1, the current density is 60 mA/cm2,the electrolytic temperature of 10℃, the electrolysis time is 100 min, the electrolyte mass fraction of 70%, the expansion volume of the expandable graphite can up to 215mL/g;The influence factors are governed the descending order, electrolyte concentration,electrolysis temperature, electrolysis time, current density. Through Particle size analysis,XRD, SEM and EDS analysis showed that the effect of expandable graphite intercalation by electrochemical method was obvious, and the expanded graphite has obvious wormlike fluffy structure.Under the same raw materials and the same technological conditions, study on the effect of graphite particle size and recycling electrolyte on the preparation of expandable graphite.The results show that the expansion volume of expandable graphite decreases with the decrease of the particle size. The recycling electrolyte can be used in the preparation of expandable graphite. The effect of the oxide layer is relatively weak, but it still has a high recovery value. The expansion volume of the expanded graphite can reach 150 mL/g with the new electrolyte. The expansion volume of the expanded graphite also can reach 70 mL/g with the recycling electrolyte. Therefore, the recycling electrolyte has a high recovery value.