Low Temperature Vapor Phase Digestion of Graphite

摘要

A method for digestion and gasification of graphite for removal from an underlying surface is described. The method can be utilized to remove graphite remnants of a formation process from the formed metal piece in a cleaning process. The method can be particularly beneficial in cleaning castings formed with graphite molding materials. The method can utilize vaporous nitric acid (HNO3) or vaporous HNO3 with air/oxygen to digest the graphite at conditions that can avoid damage to the underlying surface.

主权项

1. A method for digestion of graphite comprising feeding a gaseous stream to contact a structure, the structure comprising graphite on a surface of the structure, the gaseous stream comprising vaporous nitric acid, the nitric acid of the gaseous stream contacting the graphite, wherein upon the contact, reaction between the graphite and the nitric acid and/or between the graphite and one or more decomposition products of the nitric acid takes place resulting in digestion and gasification of the graphite and removal of essentially all of the graphite from the surface.