Wolframite

Scandium is apparently much more abundant (the 23rd most) in the sun and certain stars than on earth (the 50th most abundant). It is widely distributed on earth, occurring in very minute quantities in over 800 mineral species. The blue color of beryl (aquamarine variety) is said to be due to scandium. It occurs as a principal component in the rare mineral thortveihte, found in Scandinavia and Malagasy. It is also found in the residues remaining after the extrachon of tungsten from Zinnwald wolframite, and in wiikite and bazzite. 

The sodium tungstate solution is filtered from the resulting slurry. Similarly, in the alkaH roasting process, the concentrate, either scheeHte or wolframite, is heated with sodium carbonate in a rotary kiln at 800°C and then leached using hot water to remove the sodium tungstate. Wolframite ores are also decomposed by reaction with a sodium hydroxide solution at 100°C. 

Carburization by Menstruum Process. The P. M. McKenna method of caihuiization (1) involves the use of mineial concentrates such as wolframite [1332-08-7] Fe(Mn)WO, and microhte [12173-96-5] ferroalloys such as iron tungstide, FeW, or high purity scrap metals in a high... 

Tungsten occurs in the form of the tungstates scheelite, CaW04, and wolframite, (Fe,Mn)W04, which are found in China (thought to have perhaps 75% of the world s reserves), the former Soviet Union, Korea, Austria and Portugal. 

Textiles) willow (Med.) lupus chafing. Wolfram, m, n. tungsten, wolfram wolframite. 

Wolframit, n. (Min.) wolframite. Wolfram-lampe, /. tungsten lamp, metall, n. metallic tungsten, -ocker, m. tungstic ocher, tungstite. -oxyd, n. tungsten oxide, -salz, n. tungsten salt. 

Nearly all transition metals are oxidized readily, so most ores are compounds in which the metals have positive oxidation numbers. Examples include oxides (Ti02, mtile Fc2 O3, hematite C112 O, cuprite), sulfides (ZnS, sphalerite M0S2, molybdenite), phosphates (CeP04, monazite YPO4, xenotime both found mixed with other rare earth metal phosphates), and carbonates (FeC03, siderite). Other minerals contain oxoanions (MnW04, wolframite) and even more complex stmctures such as camotite, K2 (002)2 ( 4)2 2 O ... 

Monazite Bastnasite Scheelite Magnetite Ferberite Wolframite Gold... 

The electrostatic separation method is the exclusive choice in some specific situations, for example in the cases of rutile and ilmenite deposits. These deposits generally contain minerals of similar specific gravities and similar surface properties so that processes such as flotation are unsuitable for concentration. The major application of electrostatic separation is in the processing of beach sands and alluvial deposits containing titanium minerals. Almost all the beach sand plants in the world use electrostatic separation to separate rutile and ilmenite from zircon and monazite. In this context the flowsheet given later (see Figure 2.35 A) may be referred to. Electrostatic separation is also used with regard to a number of other minerals. Some reported commercial separations include those of cassiterite from scheelite, wolframite from quartz, cassiterite from columbite, feldspar from quartz and mica, and diamond from heavy associated minerals. Electrostatic separation is also used in industrial waste recovery. 

Complex oxides Chromite niobite-tantalite pyrochlore ilmenite wolframite scheelite... 

Ta)205 with traces of wolframite and manganese. This type of cassiterite is fragile and tends to slime during grinding. 

Group 2 Cassiterite from quartz veins. Cassiterite from this group contain about 1% (Nb,Ta)205 and about 03-0.4% wolframite. 

Group 3 Cassiterite from sulphide veins usually contains vanadium, sulphur and wolframite. 

Tin concentration from these deposits is further complicated because these deposits contain sulphides, and occasionally tin-bearing sulphides. These sulphides have to be removed from the final tin concentrate. Some ores (New Brunswick, Canada) contain wolframite, which is removed by either flotation or high-intensity magnetic separation. 

Ta/Nb minerals often occur as impurities in ilmenite, rutile, cassiterite, wolframite and perovskite, most of which contain REE. Because tantalite and columbite have similar chemical properties, they often replace each other, and are usually found as isomorph mixtures. Tantalum and niobium can also be found as separate minerals. Tantalite and microlite are primary sources of tantalum. 

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