Crucibles for melting platinum

• Book ID: 104117938
• Publisher: Elsevier Science
• Year: 1912
• Tongue: English
• Weight: 62 KB
• Volume: 173
• Category: Article
• ISSN: 0016-0032
• DOI: 10.1016/s0016-0032(12)90504-9

✦ Synopsis

ductility of tungsten so that it can be made into wire for lamp filaments. The tungsten is treated at red heat with a mixture of hydrogen and sulphur chloride. This removes any tungsten oxide, which is a cause of brittleness. The oxide is converted into sulphide, and the sulphide reduced by hydrogen. The purified metal contains some sulphur, which is expelled by heating to whiteness in a vacuum furnace, and pure metallic tungsten of great ductility is obtained, which can be easily drawn into wire. If the tungsten oxide is reduced directly by hydrogen, some hydrogen is left in the metal and causes brittleness.