PRODUCTION OF TUNGSTEN FROM SECONDARY RAW MATERIAL

摘要

During the 1980s, tungsten production wastes constituted 20-25 percent of the total amount of tungsten consumed abroad [1, 2]. The proportion of wastes given are somewhat excessive, since when citing the total amount of consumed tungsten products, the amount of chemical compounds of tungsten being used was not included (ammonium paratungstate, WO_3). It is nevertheless evident that their maximum levels were reached in 1982-1983, i.e. during the period of the greatest drop in production and consumption of primary products-concentrates and ammonium paratungstate (PVA). The total capacity for production or regenerated tungsten in the USA is estimated to be 1.8-2.5 thousand tons/year [1, 2]; for Japan - it is estimated as 500 tons/y r [1]. The plants with the greatest capacity for processing wastes are: Huntsville of the Teldyne Wah Chang Corp. (USA) - at 1,000 tons/y r [4]; the Goslar firm of Herman-G. Stark (FRG) - over 1,000 tons/year [5, 6]; the Gros-Pierre plant of the Coldstream Co., (Belgium), and the Tinton Falls Plant of the Metallurgical Industries Co. (USA) [7]. Specialists believe that the proportion of tungsten obtained from different sources of raw material can be 50 percent [8].