【作者】 宫象亮；

【导师】 牟春博；

【作者基本信息】 青岛大学 ， 材料学， 2008， 硕士

【摘要】 早期制备的膨胀石墨产品中残留的硫会腐蚀金属,并且在温度较高,有氧化剂存在的条件下极易被氧化,使密封效果下降,因此无硫抗氧化性可膨胀石墨的研究备受关注。本文采用分步反应法,在硝酸酸性条件下,分别用双氧水和高锰酸钾作为氧化剂,磷酸做辅助插层剂,用不同浸渍剂进行多次浸渍插层制备无硫抗氧化性可膨胀石墨,并对膨胀石墨的性质进行一系列的研究。本文探讨了硝酸用量、氧化剂种类和用量、反应温度和时间、磷酸用量、插层温度和时间、干燥温度和时间及膨胀温度和时间等对可膨胀石墨膨胀体积的影响规律,采用正交试验方法分析并确定分别用双氧水和高锰酸钾作为氧化剂制备无硫可膨胀石墨的最佳工艺条件（最大膨胀体积）是:石墨（g）:HNO₃（ml）:H₂O₂（ml）:H₃PO₄（ml）=5:12:0.5:7,反应时间是60min,反应温度为25℃;石墨（g）:HNO₃（ml）:KMnO₄（g）:H₃PO₄（ml）=5:12:0.6:7,反应时间是80min,反应温度为35℃。在此条件下制备的无硫可膨胀石墨的膨胀体积分别可达270mL·g^-1、280 mL·g^-1。在前面实验确定的最大膨胀体积工艺条件的基础上,用不同浸渍剂进行多次浸渍插层制备无硫抗氧化性可膨胀石墨。用NaH₂PO₄、H₃BO₃和H₃PO₄混合溶液进行浸渍插层制备的无硫抗氧化性可膨胀石墨的膨胀体积及抗氧化性都有了明显提高。实验发现,H₂O₂做氧化剂制备的膨胀石墨的抗氧化性明显强于用KMnO₄做氧化剂制备的膨胀石墨的抗氧化性。对可膨胀石墨的水分、挥发分、灰分等进行了测试。制备的可膨胀石墨产品不含硫、灰分低,产品品质高。更多还原

【Abstract】 The early expanded graphite contains sulfur which can erode the metal when used as sealing materials.In addition,on the condition of high temperature and ample oxidant,the expanded graphite can easily be oxidized that causes the effect of seal to drop.Therefore,the study on sulfur-free & anti-oxidation expandable graphite preparation has been paid more attention.By adopting the step method,the sulfur-free & anti-oxidation expandable graphite was prepared using hydrogen peroxide and potassium permanganate as the oxidants respectively,nitric acid and phosphoric acid as the reagent and different solutions as the impregnant and a series of capabilities were tested.The influence factors were discussed in detail,such as the quantity of nitric acid, the kind of oxidants and quantity,the oxidation temperature and time,the quantity of phosphoric acid,the insertion temperature and time,the torrefaction temperature and time,the expanded temperature and time.The best reaction conditions were obtained by using the orthogonal test method respectively.The optimum technological conditions are as follows:Graphite（g）:HNO₃（ml）:H₂O₂（ml）:H₃PO₄（ml）=5:12:0.5:7, the reaction time is 60min,reaction temperature is 25℃;Graphite（g）:HNO₃（ml）: KMnO₄（g）:H₃PO₄（ml）=5:12:0.6:7,the reaction time is 80min,reaction temperature is 35℃.On these condition,the expanded volumes are 270 mL·g^-1 and 280 mL·g^-1 respectively.On the basis of the former optimum technological conditions,the sulfur-free & anti-oxidation expandable graphite was prepared with different solutions as the impregnant.The results show the expandable graphite prepared using hydrogen peroxide as the oxidant,sodium dihydrogen phosphate,boric acid and phosphoric acid mixture as the impregnant has high expanded volume and maximum anti-oxidation.The sulfur-free & anti-oxidation expandable graphite that was prepared with hydrogen peroxide as the oxidant has higher anti-oxidation than the potassium permanganate did.The contents of water,volatile and ash were tested.The products have no sulfur or ash,and the qualities are high.更多还原