Types of tungsten

There are more than ten kinds of tungsten ores, and there are mainly two kinds in China: wolframite (tungstate of manganese and iron) and scheelite (calcium tungstate).

1. Wolframite (FeMn) WO4. The color has dark gray, light red brown, light brown black, hair brown and iron brown and other colors. Semi metallic luster, metallic luster and resin luster. They are usually foliate, curved, granular and dense; some are monoclinic crystals such as thick plate and pointed columnar, which are often filled in granite and its nearby rock fractures in the form of vein together with white quartz. Hardness 5-5.5, specific gravity 7.1-7.5. Uneven fracture. It is brittle and weak magnetic. Wolframite is the main raw material for refining tungsten and producing tungstate. The traditional process uses alkali fusion method.

2. Scheelite CaWO4. The color is grayish white, there are also yellow brown, green and light red. Greasy luster. It belongs to the orthorhombic system, forming biconical pseudooctahedral or plate-shaped crystals. Sometimes, oblique stripes can be seen on the crystal face, and the intercalated twins are more common. Some crystals are in the shape of shell, kidney, granular and dense block. The hardness is 4.5-5 and the specific gravity is 5.9-6.2. It is brittle with shell or uneven fracture. When irradiated by fluorescent lamp, scheelite can emit beautiful light blue fluorescence. Scheelite minerals are found in Dayu, Xiushui, Rucheng, Anhua, Linwu, Luanchuan, Wenshan, Yunnan, etc. Polygenetic placers,

The wolframite concentrate or Scheelite Concentrate can be obtained by gravity separation (shaking table, jigging, etc.), flotation, chute and heavy sand washing.