硫酸-氢氟酸分步法提纯石墨的工艺研究

用硫酸与氢氟酸分步对原料石墨进行酸浸提纯,分别研究了硫酸和氢氟酸的反应温度、用量、反应时间对提纯效果的影响。采用外加磁场的反应器,大大缩短反应时间,提高反应效率。制取高纯石墨的最佳条件为:硫酸反应温度为80℃,6 mol/L的硫酸用量90 m L,反应时间为2 h;氢氟酸反应温度为50℃,质量分数20%的氢氟酸用量为80 m L,反应时间为2 h。经过硫酸-氢氟酸提纯之后的石墨,固定碳质量分数从79.03%可提高到98.65%,此工艺能有效缓解我国高纯石墨依靠进口的局面,应用前景广阔。

Study on Preparation of High-Purity Graphite by Stepwise Purification with Sulfuric Acid/Hydrofluoric Acid

The raw material graphite was purified by sulfuric acid and hydrolfuoric acid. The effects of temperature, the concentration of acid and the reaction time were discussed. A reactor with magnetic field was applied in this reaction, the reaction time was greatly reduced and the reaction efifciency was highly increased. The optical process conditions were as follows: sulfuric acid reaction temperature was 80℃, the mole fraction of sulfuric acid was 6mol/L, the amount of sulfuric acid was 90mL and the reaction time of sulfuric acid was 2 h; the reaction temperature of hydrolfuoric acid was 50℃, the mass fraction of hydrolfuoric acid was 20%, the amount of hydrolfuoric acid was 80mL, and the reaction time was 2h. After sulfuric acid-hydrofluoric acid fractional step method, the fixed carbon content of graphite could be improved from 79.03% to 98.65%. This process can effectively alleviate the country to rely on imports of high-purity graphite and has a broad application prospects.