Tungsten was discovered in 1781 by Swedish chemist Schoeller. By the beginning of the 20th century, due to the development of a series of applications, such as the first exhibition of high-speed steel with tungsten as an alloying element and the light bulb made of tungsten wire at the Paris World's Exhibition in 1900, and the development of tungsten carbide-based sintered cemented carbide in 1927-1928, the tungsten metallurgical industry began to be born and developed.
In order to meet the increasing quality requirements of users for tungsten products, reduce costs and reduce environmental pollution, tungsten metallurgy technology has made great progress, and new advanced technology has completely replaced the traditional technology. It is mainly reflected in the following aspects:
In terms of the decomposition of tungsten mineral raw materials, the early industrialized soda pressing cooking method has developed into a general technology that can not only process scheelite concentrate, low-grade scheelite medium-ore, but also black-to-white tungsten mixed ore, and on the basis of theoretical research, the NaOH (sodium hydroxide) decomposition method has developed from a low-calcium wolframite concentrate to a general technology that can treat various tungsten mineral raw materials, including scheelite concentrate and refractory tungsten medium-ore. Of course, with the development, traditional methods with low efficiency and serious environmental pollution, such as NaOH melting, soda sintering, and hydrochloric acid decomposition, have been phased out. At the same time, it also reduces the requirements for mineral processing and greatly improves the resource utilization rate.
In the preparation of pure tungsten compounds, the strong alkaline anion exchange purification and transformation process of crude Na2WO4 solution, as well as the characteristics of short process, low cost and high product quality, have replaced the classic magnesium salt purification-traditional chemical transformation process to a large extent. The purification and transformation of the quaternary ammonium salt extraction method corresponding to it has begun to move from laboratory research and development to industrialization, presenting a gratifying prospect. The selective precipitation method has been successfully developed and widely used to remove molybdenum, tin, antimony, arsenic and other high-efficiency purification and impurities from tungstate solution, which has greatly improved the purity of tungsten products and the adaptability of tungsten metallurgical process to raw materials.
In the preparation of tungsten metal powder, in the 70s of the 20th century, the advanced blue tungsten hydrogen reduction method replaced the yellow tungsten hydrogen reduction method, and by the end of the 20th century, the purple tungsten hydrogen reduction method further replaced the blue tungsten hydrogen reduction method, so that the physical properties of the tungsten powder control reached a more advanced level, and further improved the quality of tungsten powder.
At the same time, the successful research and development of a variety of technologies for the treatment of tungsten metallurgical secondary resources has greatly improved the utilization of tungsten secondary resources in terms of technical level and recycling rate.
Science and technology are the primary productive forces, and tungsten resources, as an important strategic material, are important resources in the world, which must be rationally recycled.