Tungsten ores minerals

Whole Flotation. If tungsten ore mineralization is too fine, the total amount of mined ore can be subject to flotation. A corresponding flow sheet of the Mittersill ore dressing plant (Wolfium Bergbau und Hiittengesellschaft m.b.H.) is presented in Fig. 5.2. 

As a specific illustration reference may be drawn to molybdenum reserve scenario in the United States. The reserves are mainly grouped under five categories (i) primary, (ii) byproduct of copper ores, (iii) co-product of copper-molybdenum ores, (iv) by-product of tungsten ores, and (v) by-product of uranium ores. These have been presented and briefly elaborated in Table 1.14. It may finally be recorded by way of summary that the present day molybdenum sources in the world today seem to be principally of two main kinds first, the large-tonnage, low-grade, disseminated type of deposit in which molybdenite is the principal economic mineral second, the deposits in which molybdenite occurs as a by-product in... 

Tungsten is recovered mostly from mineral scheebte and wolframite. The recovery process depends on the mineral, the cost, and the end use i.e., the commercial products to be made. Typical industrial processes have been developed to convert tungsten ores to tungsten metal and alloy products, tungsten steel, non-ferrous alloys, cast and cemented tungsten carbides, and tungsten compounds. A few processes are mentioned briefly below. 

While the blendes contain indium as the sulfide, continued Winkler, Hoppe-Seyler found it in another form, which could not be definitely determined, in a tungsten ore from an unknown locality, and later in the wolframite from Zinnwald. The latter contains 0.0228 per cent of indium. In the meantime, I have placed many minerals (without previous concentration, to be sure) before the slit of the spectroscope, but have never found one which gave the desired reaction. It therefore seems as if the occurrence of indium in nature is exceedingly scarce or it must in most cases play the role of a difficultly discoverable satellite (81). 

Tungsten ore crystallization can be classified as near-source high-temperature deposits, because wolframite as well as scheelite range on the high-temperature end of the series of minerals crystallizing from hydrothermal liquid. Due to the properties of this liquid, a move to further distant places may also occur. 

The particle size of the tungsten ore which determines the degree of disintegration necessary to liberate the tungsten mineral (liberation size). 

Beneficiation of tungsten ores by gravity was the classical method, followed by a cleaning step (Fig. 5.1). The recovery depends on the ore characteristics (mainly liberation size) and ranges typically between 60 and 85%. The main loss is in the slimes, because the tungsten minerals are the most fiiable ones present in ores. 

The mngsten ore called scheehte is named after Carl Wilhelm Scheele (1742—1786), who smdied and experimented with tungsten minerals, but as with many of his other near discoveries, such as oxygen, fluorine, hydrogen sulfide, hydrogen cyanide, and manganese, he was not given credit. 

In the mid-1700s a number of scientists experimented with and attempted to isolate element 74 by treating ores of other metals with reagents. One problem was that tungsten was often confused with tin and arsenic. It was not until 1783 that Don Fausto de Elhuyar (1755-1833) and his brother Don Juan Jose de Elhuyar isolated a substance from tin ore that they called wolframite. They named it after the mineral in which it was found. At about the same time the Swedish named it tung sten, which means heavy stone in Swedish. This explains the potentially confusing use of W for the symbol for tungsten. 

---