Preparation Of Expandable Graphite
1, standby chemical intercalation of initial raw material of high carbon Flake graphite, other chemicals such as sulfuric acid (98%), hydrogen peroxide (28%), with industrial-grade reagents such as potassium permanganate. Preparation steps: at the appropriate temperature, different ratios of hydrogen peroxide solutions, natural Flake graphite and concentrated sulfuric acid in different accession procedures, response time under stirring, and then washed to neutral, centrifuged, dried at 60 ° c vacuum drying.
2, electrochemical method in treatment of graphite powder a strong acid in the electrolyte to produce an expandable graphite, hydrolysis, wash and dry. As a strong acid using sulfuric acid or nitric acid. This method of expandable graphite has low sulfur content.
3, in the process of preparation of expansible graphite by ultrasonic oxidation and ultrasonic vibration of anodizing electrolyte, same time with anodizing time of ultrasonic vibration. Due to ultrasonic vibration of the electrolyte in favour of cathode and anode polarization, Anodic oxidation speed so as to speed up and shorten the time.
4, the vapor diffusion method graphite intercalation respectively in a vacuum and seal both ends of the tube, in the end heat of intercalation, differential pressure using the temperature difference between the ends to form a necessary response, intercalation into graphite in a small State, which made of expandable graphite. This method of producing expandable graphite number of segments can be controlled, but the high cost of production.
5, molten salt method of several hybrid heating insert and graphite composite formed expandable graphite.