低污染可膨胀石墨的制备

Preparation of expandable graphite with low pollution

为杜绝重金属离子的污染,采用双氧水取代传统的高锰酸钾制备可膨胀石墨,研究硫酸、硝酸铵、双氧水用量及反应时间等因素对石墨膨胀容积的影响规律,并采用正交实验法,确定制备可膨胀石墨的最佳工艺。结果表明:石墨10 g、浓硫酸22 mL、双氧水1.7 mL、硝酸铵3.0 g、反应时间45 min的条件下,制备的可膨胀石墨膨胀容积为180 mL/g,膨胀后硫质量分数为0.26%。采用XRD和SEM对膨胀石墨的晶体结构和微观形貌进行了表征,发现石墨晶体结构未破坏,石墨层间距变大。

This paper introduces an effort to prevent heavy metal pollution by preparing expandable graphite using hydrogen peroxide to replace the conventional potassium permanganate. The effort consists of a research into the law underlying the effect of volume expansion of different factors of sulphuric acid, ammonium nitrate, hydrogen peroxide dosage and reaction time on the preparation of expandable graph- ite; using orthogonal experiment to determine the optimum extraction process by which to prepare expand- able graphite： graphite of 10 g; sulfuric acid of 22 mL; hydrogen peroxide of 1.7 mL; ammonium nitrate of 3.0 g; and the reaction time of 45 min. The proposed conditions produce expandable graphite with the expansion volume of 180 mL/g and sulfur content of 0.26% due to graphite expansion. The character- ization of crystal structure and microstructure of expanded graphite by XRD and SEM finds little destruc- tion in the structure of graphite and a wider space between layers.