raw tungsten ores processing method

Due to its unique chemical and physical properties, tungsten has been widely used in the important field of military aerospace, machinery, electronic, petroleum and metallurgy etc. So far, there are more than 20 kinds of tungsten minerals and tungsten-bearing minerals of which have the mining value mainly are wolframite and scheelite. The tungsten ore dressing experienced from simple hand sort to simple hydraulic elutriation, from simple machine election to standardize process gravity concentration, from single gravity concentration to the development of combined flowsheet which consist of gravity concentration, magnetic separation and flotation etc.

1.1 Wolframite ore dressing

Wolframite usually is large quartz or thin vein type tungsten deposit, it belongs to gasification and high temperature hydrothermal type deposit, wolframite is gathered in quartz and seems like thick plate or thin vein crystal which is distributed coarsely and easy to separate. This type of tungsten ore has very important industrial value as it has features of large scale and easy to be selected.

Wolframite distributed in quartz gangue unevenly, the size of the large crystal can reaches to more than 100mm, wolframite appears thick plate or thin and narrow vein with the nonuniform thickness and high mining dilution rate. According to the surrounding rock and gangue which can easily identifiable characteristics and the difference of surface properties, some wastes should be abandoned by roughing before gravity concentration.

The mineral separation for wolframite commonly adopt the combined mineral processing technology which mainly use the gravity separation. Generally it is divided into roughing, gravity separation, selection and fine mud treatment etc. The principle procedures for the wolframite ore dressing are: pre enrichment, hand pick throw waste; multistage jig, multistage table, stage grinding, shaking table drop tail; fine mud return processing, various process selection and mineral comprehensive recovery.

The main mineral processing equipment are: jaw crusher, cone crusher, roller crusher, rod mill, ball mill, jig, hydraulic classifier, shaking table, flotation machine, magnetic separator and electric separator, etc.

1.2 Scheelite ore dressing

The main tungsten resources for scheelite are sandstone type, composite type (veinlet-disseminated type-greisen skarn composite type), often associated or disseminated with variety of non-ferrous metals such as copper and bismuth. The particle size for the useful minerals is fine and is embedded disseminated in ore. The ideal dissociation size for the scheelite most belongs to the flotation size range, also the flotation performance is better than the wolframite, thus flotation is the main ore dressing process for scheelite.

Scheelite Flotation is generally divided into tungsten sulfide flotation, roughing and selection. The principle flow of sulfide flotation is similar to that of common sulfide ore flotation plant, the difference is the components of sulfide ore. Scheelite roughing using sodium carbonate and water glass as modifying agent, flotation with fatty acid collector, part of concentrator with chelating collector; Scheelite roughing and selection currently has two selection process, one is heated flotation and another is normal temperature flotation.

Beneficiation method of scheelite is flotation, the conventional idea is direct flotation. Actually not all the mineral properties are the same, especially for the rich ore in Africa, the beneficiation method should depends. The reasonable beneficiation process flow and equipment configuration should be design under the specific circumstances to achieve the highest economic benefit in equal investment conditions. Thus the scheelite beneficiation is flotation and purification or gravity separation enrichment in advance then flotation and purification should be considered depend on the actual situation.

The following are the scheelite pictures which exported to Nigeria by Forui Machinery, this type of scheelite cannot directly flotation, the final concentrate can  be get by direct gravity separation, and the investment for the dressing plant is only 1/10 compared with the flotation plant.