低污染可膨胀石墨的制备

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。

Preparation of expandable graphite with low pollution

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.