Intensification of the process of metallizing tungsten­containing ore raw materials by the powder metallurgy method

• Main Authors: Stanislav Hryhoriev, Damir Bikulov, Viсtor Skachkov, Olga Berezhnaya, Oleksandr Oliynyk
• Format: Article
• Language: English
• Published: PC Technology Center 2019-08-01
• Series: Eastern-European Journal of Enterprise Technologies
• Subjects: tungsten concentrate; carbothermic reduction; induction heating; metallization; phase analysis; microstructure; resource conservation
• Online Access: http://journals.uran.ua/eejet/article/view/176628
• ISSN: 1729-3774; 1729-4061

X-ray diffraction phase analysis of samples performed on a DRON-6 diffractometer has shown that the processes of CaWO4 transition to WC and W2C had the highest probability in the temperature range of 1,173–1,473 K. The end-product CaWO4, thermally treated with carbon, was represented by carbon in oxycarbide and carbide phases. The processes of tungsten reduction from its oxides through the phases of formation of tungsten carbide and oxygen compounds (higher and lower) and finally tungsten metal were shown. Basic chemical and phase transformations occurred within the temperature range of 300–1,800 K. This opens the prospect of producing tungsten as an alloying material without formation of liquid phases in a heterogeneous system and enables production of tungsten based alloying material at relatively low temperatures which significantly reduces power consumption. Qualitative and quantitative composition of charge materials for laboratory studies and industrial tests in a form of briquettes for metallization of tungsten-containing compounds in a furnace with induction heating was presented. The mechanism of phase and structural transformations occurring in reduction of tungsten from scheelite concentrates in the temperature range of 1,273–1,473 K and microanalysis of samples of chemical transformations were studied. A furnace unit with induction heating in which industrial tests were performed in stages was schematically shown. The tests have shown that a 1.3 times sample weight reduction and a 23 % specific density reduction occurred in the process of heat treatment of the samples based on scheelite concentrate. Several batches of spongy tungsten instead of standard ferrotungsten were produced and tested in smelting high speed steels. Advantages of the new technology of tungsten metallization from a scheelite concentrate and positive efficiency of using the new material in special metallurgy were shown.