用非高纯鳞片石墨制备无硫低灰分可膨胀石墨

Preparation of sulfur-free and low ash expandable graphite from non-high purity flake graphite

以非高纯混合目天然鳞片石墨、硝酸、高锰酸钾为原料,采用化学法经氧化酸化插层、水洗、干燥过程制备无硫低灰分可膨胀石墨。利用正交实验方法确定最佳工艺条件,并对相关影响因素作了初步分析。结果表明:在石墨、高锰酸钾和硝酸的用量比为1.0∶0.2∶6.0,反应时间是60 min,反应温度为40℃,H2O2用量为2 mL的条件下,可以制备出膨胀体积为260 mL/g的无硫低灰分可膨胀石墨。影响反应体系最大的是高锰酸钾用量,依次是硝酸用量、反应温度、反应时间。该工艺方法简单、成本低、易操作,适合工业化生产。

This paper features the preparation of sulfur-free and low ash expandable graphite from non-high purity mixture mesh natural flake graphite,concentrated nitric acid and potassium permanganate as oxidant by a chemical method.The paper introduces the determination of optimized conditions for preparing the expandable graphite by an orthogonal test method and gives an initial analysis of relevant factors.Results show that the optimum ratio of flake graphite∶ potassium permanganate∶ nitric acid of 1.0∶ 0.2∶ 6.0,reaction time of 60 min,reaction temperature of 40 ℃ and 2 mL hydrogen peroxide allow the production of sulfur-free and low ash expandable graphite of 260 mL/g.The biggest factor affecting reaction system is amount of potassium permanganate,followed by the amount of nitric acid,reaction temperature and reaction time.This technology of simpler process,lower cost and easier operation promises to come into use in manufacturing industry.