Low Grade Scheelite Tailings Recovery Method

China is a large producer of tungsten, and its reserves and output rank first in the world, but this is not worth showing off. Due to historical reasons and technical limitations, the development of tungsten resources in the early and middle stages of China has not been carried out reasonably. 

The utilization rate of scheelite resources is less than 50%, and a large amount of scheelite is lost in tailings. With the continuous mining of tungsten-containing polymetallic mines, the stockpile of tailings is becoming larger and larger, which not only occupies a large amount of land, but also pollutes the environment. Therefore, it is of great significance to recover low grade scheelite from tailings.

At present, a low-cost beneficiation method for selecting scheelite concentrate from tailings of low grade scheelite is adopted by a certain enterprise in Hunan. It is implemented through the following technical solutions:

1)Gravity separation tailings throwing: low grade scheelite tailings are screened and separated from slag to obtain gravity concentrate and gravity tailings;

2)Iron removal by magnetic separation: iron ore tailings and iron concentrate are obtained by gravity separation at 1000 ~ 3000Gs magnetic induction intensity.

3) Sulfide flotation: according to the calculation of tailings feeding per ton, 500-1500 grams of sodium carbonate are added to the tailings of iron dressing, mixing for 1-5 minutes, 50-150 grams of xanthate as collector, 5-30 grams of 2# oil as well as mixing for 1-5 minutes, roughing once and scavenging once or twice, sulfur tailings and sulfide ores are obtained.

4)Rough separation of scheelite at room temperature: according to the calculation of tailings feeding per ton, adding adjusting agent sodium carbonate 500-1500 g, sodium silicate 500-5000 g, stirring for 1-10 minutes; collector sodium oleate 100-500 g, stirring for 1-10 minutes, doing one roughing, 2-3 sweeping and 2-3 concentrating to obtain scheelite and flotation tungsten tailings. ;

5) Scheelite heating concentration: Scheelite concentrate concentrates to 60-80% concentration, according to the calculation of tailings feed per ton, adding 200-2000 g sodium silicate, heating to 80-100 ℃ and stirring for 30-120 minutes, flotation scheelite concentrate and heating tailings, heating tailings to return to scheelite normal temperature roughing operation. For the tailings containing scheelite WO₃ 0.03-0.15%, the final scheelite concentrate Grade WO₃ 35-55% and recovery rate 50-65%.

The technical scheme has the following characteristics: 1) discarding 60-70% interfering mud and light minerals by gravity separation and discarding tail, enriching low grade scheelite, which is very important to improve the separation index of scheelite; 2) removing iron by magnetic separation before scheelite separation, which greatly reduces the iron content in tungsten concentrate, and this operation improves the tungsten concentrate. The quality of ore is very important; 3) The reagent system is simple, non-toxic, and the collector sodium oleate is cheaper, which provides an effective way to reduce the cost of mineral processing and environmental pollution, and can deal with and recover the tailings from the tailings reservoir of polymetallic mines.

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