Obtaining Especially Large-Sized Crucibles from Porous Tungsten Using Environmentally Friendly Fluoride Transition with a Circuit of Reagents

Abstract

The level of optimization of the technological process based on fluoride redistribution in tungsten technology allows starting production of dense crucibles with a diameter of 700–1000 mm and height of 800–1100 mm with any wall thickness. The technology provides fluorination with further restoration of hydrogen-synthesized WF₆ on the surface of copper substrate and the use of evolved HF for obtaining fluoride and hydrogen. Circulation of the used reagents provides observance of ecological standards. The proposed “closed” circuit of the apparatus, consuming tungsten powder or metal waste, provides performance on finished products of 93–127 t/year and can be replicated. Expenses on the creation of one production circuit for manufacturing tungsten crucibles by the described technology are paid off within 2 months of operation. Inclusion of rectification cleaning of WF₆ into the technological circuit allows obtaining tungsten products of high purity. The new technology guarantees crucible production of a strictly set shape with high purity of the inner surfaces from dense tungsten with increased physical-mechanical properties and low degradation of properties during operation, which allows using crucibles with less wall thickness.