Scheelite flotation

Schescheite CaWo4, containing 380.6% of Wo, was collected by fatty acid and its soap in flotation. Sodium carbonate is commonly used as pH regulator.When using fatty acid as collector, the optimum pH is 9~10.Inhibitors can be water glass, dextrin, starch and so on.Although scheelite is good in floatability, from the economic point of view, the recovery of coarse scheelite is usually by redoing the procedure.

Fine material embedded in the scheelite ore, generally with flotation, or the first floating low - grade concentrate after off - hydrometallurgical treatment.Oleic acid or sodium oleate is often used as collector in scheelite flotation.The mixture of oleic acid and kerosene can reduce the amount of oleic acid in flotation.Silicates and dispersed gangue slime are usually inhibited by sodium silicate.

The separation of scheelite from sulfide ore and other non - metallic ore should be paid attention.

(1) Scheelite to be separated from sulfide ore.Generally in the flotation of scheelite before, firstly use of xanthate to collect surfacing sulfide ore.During scheelite flotation,  also add a small amount of cyanide, inhibit the remaining sulfide ore.

(2) Scheelite to be separated from calcite and fluorite.In the flotation of scheelite, water glass as inhibitor, according to the different process can be divided into:

     1） Strengthen stirring at room temperature.A large amount of sodium silicate (10~20kg/t) was added to concentrate the scheelite ,concentrate containing calcite and fluorite. It was stirred for a long time (up to 14~16h) at room temperature. After dilution of the pulp, the flotation of scheelite was carried out.The advantage of this method is that the flotation process is carried out at room temperature.Its disadvantage is too long and need time, generally used less.

     2） Thick slurry high temperature method, also known as "Petrov method".It is the white tungsten rough concentrate containing calcite and fluorite concentrate to 60 ~ 70% solid, and adding sodium silicate, during the heating to more than 80 ℃.30 ~ 60 min, stir and diluted, flotation scheelite at room temperature, product in tank is fluorite and calcite.

(3) Scheelite is separated from quartz silicate.Using oleic acid as collector and adding water glass as inhibitor can restrain quartz and silicate gangue effectively.The order of inhibition of sodium silicate is:

Quartz > silicate > calcite > apatite > molybdate > barite > scheelite.

(4) Scheelite is separated from barite.The inhibition effect of sodium silicate on scheelite and barite is close to each other, so using sodium silicate as an inhibitor cannot separate scheelite and barite well, so the following two methods are used to separate them:

     1) Using alkyl sulfate sodium salt as collector, in acid pulp, first flotation out of mixed concentrate, and then in the strong acid medium, add water glass, add alkyl sulfate sodium surfacing barite, the product in the tank is scheelite.

     2) The rough concentrate roasting under the temperature of 300 ℃, then diluted to liquid:solid =5:7.1, using barium chloride as activator, flotation barite.When the slurry concentration is liquid:solid =5:1, add sodium hydroxyl sulfate and barium chloride to float again. The resulting tailings are low-grade scheelite concentrate, which is then sent to hydrometallurgy.

(5) Separation of tungsten and molybdenum.First flotation molybdenum ore, then oleic acid surfaced scheelite ore.Flotation of scheelite, roughing coarse ore enrichment, add a lot of water, and steam heated to above 90 ℃, 30 ~ 40 min, stirring mixing after filtering, the pulp density of 16 ~ 20% solid, then through secondary roughing, we will get white tungsten concentrate.