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Tungsten

Tungsten

Release time:23 August 2019
Tungsten

Type
Element (Minerals/Ores of)

Mineral Classification
Tungstate

Chemical Formula
scheelite (CaWO4, calcium tungstate) and wolframite ((Fe,Mn)WO4, iron-manganese tungstate).

Streak
White (sheelite), Redish Brown (wolframite)

Mohs Hardness
4.5-5 (sheelite), 4-4.5 (wolframite)

Crystal System
tetratongal (sheelite), monoclinic (wolframite)

Color
Colorless, white, gray, brown, pale yellow, yellow-orange, pale shades of orange, red, green; may be (sheelite)
Grayish to brownish black (wolframite)

Luster
vritreous, adamantine (sheelite), submetallic, resinous (wolframite)

Fracture
Subconchoidal, Uneven (sheelite), Uneven, Rough (wolframite)

Description

Tungsten (W) is a gray-white metallic element that is stable and is very resistant to acids and bases. Tungsten has the highest melting temperature of any metal (3422 ° C or 6192 ° F), and the second highest of all elements (carbon is highest).

Relation to Mining

Tungsten is retrieved from the ore minerals scheelite (CaWO4, calcium tungstate) and wolframite ((Fe,Mn)WO4, iron-manganese tungstate). A significant amount of tungsten is recovered through recycling of scrap tungsten products.

Uses

Tungsten is mixed with carbon to make a very strong, very resistant material called tungsten carbide. Tungsten carbide is used to make cutting tools and wear-resistant tools for metalworking, drilling for oil and gas, mining, and construction.

Because it has such a very high melting point and low vapor pressure, tungsten is used in high temperature situations. For instance, the filaments in light bulbs are made of tungsten. It is used in other applications in electronics as well.

When added to steel, tungsten increases its strength. It is alloyed (mixed with) other metals to make “superalloys” which have special physical properties of high strength and heat resistance. Some of the applications for such superalloys are in turbine engines for jet aircraft and energy generation.

It is also used in textile dyes, enamels, paints, and for coloring glass.

Related cases

Wolframite gravity separation process

The wolframite ore has a high depletion rate, low grade, coarse grain size, high density, low hardness, easy mud formation and deep color, which is mainly extracted by the gravity separation process. China’s wolframite ore beneficiation production has a history of more than 70 years and has accumulated rich experience, which can be summarized as the following parts.
1. Pre-enrichment, early throwing the waste rock, then washing, desliming, grading, crushing.
The dilution ratio of wolframite mining is generally around 80%. The amount of surrounding rock in the ore is large, and are easy to distinguish with wolframite containing rock. Pre-select the waste rock increases the beneficiation processing capacity and efficiency, and reduces the rock crusher wear.

2. Gravity separation, grading and sorting. Jig concentrator – shaker table to recover the coarse particle wolframite.

3. Fine wolframite slime concentration
Fine wolframite slime includes primary and secondary slime, which accounts for about 10% of the original ore. The tungsten grade is higher than the original ore, grade is 14% to 15%. Extract tungsten from slime is an important method for improving the tungsten recovery rate.
Wolframite slime concentration machines have shaker tables, centrifugal concentrators, belt chute, flotation, magnetic separation. The fine mud recovery rate has increased from 10% ~ 50% to 60%~70%.

Case study: wolframite plant

Take the Pangushan tungsten wolframite plant as an example, further explore the tungsten ore processing flow and technique.

【Ore characteristics】
Mineral composition: Quartz-wolframine-sulphide type composite deposit, mainly contains wolframite, bismuthinite, auxiliary minerals like scheelite, pyrite, pyrrhotite, molybdenite and chalcopyrite.
Surrounding rocks mainly in quartz stone, slate and phyllite rocks.
【Capacity】800t/d
【Target minerals】
wolframite, scheelite, bismuth and sliver.
【Extraction & beneficiation】
Crushing – washing – hand picking – grinding – jig concentrator – shaker table – flotation – magnetic separation.
complete processing flow divided into 4 parts, primary separation, gravity separation, slime recovery, and concentration.
【Equipment】

ItemEquipmentQtyMaximum capacity
 #1 Crushing T/H(set)Feeding size(mm)Discharge size(mm)Ore loose density
Coarse crushing400*600 jaw crusher160<150<921.7
Medium crushing250*500 jaw crusher224~26<25<201.7
Fine crushing750*500 roller crusher2 FALSE3~51.7


 #2 Grinding & grading T/H(set)Feeding size(mm)Grinding fineness
Stage 1900*2400 rod mill4 -10-2.5mm
Stage 2900*2400 rod mill1 -2.5-40mesh
 #3 Flotation, gravity, magnetic separation T/H(set)ConcentrationFeeding size(mm)
FlotationFlotation machine12 30%~35%-80 mesh
Magnetic separationThree disc magnetic separator3  -60/-1.8mm
Gravity separationSpring shaker table8   
 600*600 jig concentrator8   
 800*700 centrifugal concentrator24   
 Belt chute8   
 #4 Dewatering T/m2Feed material moisture%Discharge material moisture%
DryerTungsten drying oven 600*5000260.1110.3
 Bismuth drying oven 600*4400171.1522.60.21

Scheelite flotation process

The scheelite accounting for 97.72% of the total amount of tungsten.
The sulfide minerals mainly include pyrite, stibnite, bismuth-copper-silver-ore, stibnite and a small amount of galena, sphalerite, beryllium ore, arsenic and bismuth.
The gangue minerals are mainly quartz, mica and a small amount of calcite, apatite, etc.

Result
The tungsten concentration was 1.09%. WO 3 grade was 71.78% and the recovery was 90.19%

scheelite flotation process

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