U. S. Bureau of Mines Collection - C-825-BC Furnaces for Vacuum Purification of Titanium
![0022:0148: U. S. Bureau of Mines Collection - C-825-BC Furnaces for Vacuum Purification of Titanium ["The crude titanium obtained in the first stage of the Kroll process is contaminated with magnesium and some magnesium chloride which did not drain out during tapping. These impurities are volatilized by heating the crude titanium under a high vacuum, pure titanium sponge remaining as a residue. The crude titanium to be purified is placed in the container in front of and above the operator standing on the flooring is then shoved up into the retort above the container. After a vacuum has been established by the pumps shown in the background, the electric furnace shown in the upper left is placed over the retort to heat it. Operated in pairs, the retort on the left will be cooled, unloaded, and reloaded, while that on the right is being heated."]](https://d8e7jbdw4fu0e.cloudfront.net/4452/52a63380-c1fb-11ee-ab27-e56e0f1cdedf-wzIJHhP.lg-nt@2x.jpg)
0022:0148
U. S. Bureau of Mines Collection - C-825-BC Furnaces for Vacuum Purification of Titanium ["The crude titanium obtained in the first stage of the Kroll process is contaminated with magnesium and some magnesium chloride which did not drain out during tapping. These impurities are volatilized by heating the crude titanium under a high vacuum, pure titanium sponge remaining as a residue. The crude titanium to be purified is placed in the container in front of and above the operator standing on the flooring is then shoved up into the retort above the container. After a vacuum has been established by the pumps shown in the background, the electric furnace shown in the upper left is placed over the retort to heat it. Operated in pairs, the retort on the left will be cooled, unloaded, and reloaded, while that on the right is being heated."]