Scheelite tungsten ore beneficiation
Scheelite tungsten ore is concentrated by gravity separation combined with floatation separation or only floatation separation according to the ore dip-drying characteristics while some scheelite tungsten ore needs pre-beneficiation like the beneficiation factory in King Island, Australia. There Uv fluorescent is adopted to remove the 50% of waste stones, and the grade will be lower than the tailings discharged from the beneficiation factory with the tungsten recovery is 90-96% &the treatment capacity is 30-40t/h.
The sulfide ore is usually mixed in the white ore bed with the molybdenite especially common. During the beneficiation, sulfide ore will be beneficiated by floatation separation, and then the Scheelite will be floated then. The floatation of Scheelite is done in alkaline medium. Na2CO3 and NaOH will be used to improve the Ph of the pulp to 9-10.5. Sodium silicate, quebracho juice, tannin, kinds of phosphate will work as inhibitor. oleic acid, sodium oleate, tall oil, oxidized paraffin wax soap will be used as collector with its own frothing capacity while most of them needs no blowing agent when working.
Scheelite ore has great floatable ability. It is usually is included in the calciam-bearing ores like calcite, fluorite, phosphorite, which makes the floatation separation sophisticated. Multi-chemical-valence metal salts like FeSO4 will be added to sodium silicate to improve the floatation efficiency of Scheelite.
To improving the pulp temperature is another way to improve the floatation efficiency. Petrov method is to absorb the collector on the calcite to float the white tungsten by making the pulp temperature up to 70-90 degrees and adding large quantity of sodium silicate.
There are not too many white tungsten beneficiation factories in China to occupy 5% of the tungsten beneficiation. The white tungsten beneficiation factory in Baoshan, Dangping, used oleic acid as collector and refined by Pstrov method and latter, the collector has been changed to oxidized paraffin wax soap of 731 which is vice-product of petrolium industry with its large resource & low price. Additionally, the pulp needs no heating and the floatation efficiency will be great in normal circomstance.
For scheelite ore, floatation separation is mainly used while gravity separation is involved sometimes. For wolframite, gravity separation is mainly used while magnetic separation can be involved sometimes. However, there are also exceptions. For some scheelite tungsten ore with coarse inlay granules, gravity separation can help to get the ideal upgrading efficiency without large investment about floatation separation plants. And if floatation separation is used for this scheelite, the recovery of high-quality scheelite will be lower and the plant investment will be large. In Africa, there are many scheelite tungsten mines with big coarse scheelite inlay size even over 5mm, and here the gravity separation can be used to recover the coarse scheelite and this lowers the schelite loss due to crushing or milling. If floatation separation is used for this coarse scheelite ore, the recovery will be lowered and this will be not so good as gravity separation. Here the scheelite tungsten gravity separator is tungsten jig separator.
For wolframite tungsten ore, gravity separation is the main way to upgrade while the magnetic separation is mainly used for the fine grain wolframite or mud.