Use of sealed tubes for the preparation of acid solutions of samples for analysis, or for small-scale refining: pressures of acids heated above 100 degrees C

This paper describes special technics suita ble for the use of sealed tubes in treating refractory materials with hydrochloric acid and other acid mixtures at eievated temperatures.Methods for filli ng, fo r sealing, and for opening tubes are discussed.The feasibility of re use of tubes of Pyrex glass is discussed with some observed phenomena of the attack of the glass by the acids.A protecting shell is described together with a method of using solid carbon dioxide to provide the compensating pressures needed to protect the sealed t ubes from bursting.The pressures developed on heating hydrochloric acid and mixtures of hydrochloric acid with nitric or perchloric acids were measured in a special gage, which is described.