Experimental study on comprehensive recovery of molybdenum and white tungsten from flotation tailings of a molybdenum ore in Henan

Henan is an important molybdenum mine base in China, and it is associated with abundant low-grade scheelite in molybdenum deposits. Since a long time has been focused on the recovery of molybdenum in the beneficiation , a large amount of white tungsten is discarded as tailings. In order to rationally develop and utilize mineral resources, an optional test study on the comprehensive recovery of molybdenum and white tungsten from the tailings of the company was commissioned by a company in Henan. The scheme of re-floating scheelite from the first floatation molybdenum ore was determined through experiments, and a good process index was obtained.

First, the nature of the sample and the process plan

(1) Nature of the sample

The sample was taken from a flotation tailings in Henan. Sample multi-element chemical analysis results are listed in Table 1.

The results show that: the sample recovery of tungsten and molybdenum as a main metal, tungsten-based to scheelite, molybdenite molybdenum-based. Tungsten and molybdenum content have reached the grade requirements for recycling. Other valuable elements did not meet the grade requirements for comprehensive recycling.

(2) Process plan and process determination

The chemical analysis of the sample indicates that the valuable elements in the ore are tungsten and molybdenum, and the minerals co-existing with scheelite and molybdenite are mainly silicate minerals. The scheelite and molybdenite are not closely embedded, and the molybdenum ore is finely sized. Therefore, the process of re-grinding the sample, preferentially molybdenum, and flotation of white tungsten under normal temperature conditions is determined.

Second, test results and analysis

(1) Full floatation desulfurization and molybdenum flotation test

The test uses a laboratory type XMQ Ф 240mm × 90mm cone ball mill , XFD series single-tank and hanging trough flotation machine, the flotation reagent uses industrial reagents, of which the water glass modulus is 2.8. The sample was mixed by crushing and then bagged. The mass of the unit sample was 3 kg, and the fineness of grinding was -0.074 mm, accounting for 70%, which was determined by the condition test. The sample contains less sulfide minerals, and the moisture content of molybdenum ore is obviously superior to that of other sulfide minerals. Therefore, the principle of mixed float sulfide ore-mixing re-grinding-selecting molybdenum is adopted. Molybdenum was selected using water glass + sodium sulfide combination prescription. The test determined that the ratio of the two was 1:5. The test results of the combination dosage are shown in Figure 1. The test flow is shown in Figure 2.

The selected test showed that the molybdenum concentrate containing Mo 4.633% and recovery rate of 57.52% was obtained by selecting the amount of the composition at 720 g/t for 5 times. The single use of sodium sulfide as a selective inhibitor has a significantly poor effect, and the foam is thick and the circulation of the medium ore is large, indicating that the auxiliary of the water glass is beneficial to the selection of the molybdenum ore, but the dosage should not be too large, otherwise It inhibits molybdenum minerals.

(II) Results and analysis of white tungsten flotation test

1. White tungsten flotation collector dosage test

The white tungsten was coarsely selected and adjusted to pH 9.5 with Na ₂ CO ₃ , and the water glass was used as an inhibitor. The dosage was 4.0 kg/t, and 731 oxidized paraffin soap was used as a collector to carry out the collector 731. The amount of oxidized paraffin soap was tested. The test procedure is shown in Figure 3 and the results are shown in Table 2. Tests showed that the amount of the soap 731 is oxidized paraffin containing WO ₃ 8.01% can be obtained when 270g / t, the recovery rate of 81.72% of coarse scheelite concentrate.

2, white tungsten rough selection inhibitor dosage test

The conventional agent is sodium carbonate as the adjusting agent, and the water glass is the gangue inhibitor. Their dosage tests are shown in Fig. 4 and Fig. 5, respectively. The single factor test showed that whether the sodium carbonate or the water glass is within the test dosage range, they have a great influence on the tungsten recovery rate, and the tungsten coarse concentrate grade has a significant change with the increase of the amount. It is generally believed that there is a synergistic effect when sodium carbonate is shared with water glass. Therefore, the factorization test is carried out with the sodium carbonate dosage of 1200 g/t and the water glass dosage of 3000 g/t as the center point. It is found that when the amount of sodium carbonate is 1000 g/t, water is used. the amount of glass 3500g / t when sorting index is more preferably obtained containing WO ₃ 9.21%, 83.68% recovery of crude scheelite concentrate.

3, white tungsten at room temperature selection test

The key to sulphur selection at room temperature is to enhance the selectivity of the inhibitor, improve foam mineralization, and reduce the cyclic loading of the mine. Water glass is generally used as an inhibitor. The main points of the process are slurry mixing and slurry flotation. There should be sufficient mixing time and strength when adjusting the slurry. The process of white tungsten selection is shown in Figure 2. In the selected test, as the amount of water glass increased, the grade of white tungsten continued to increase, but the recovery rate also decreased. When the amount of selected water glass is 1000g/t, the grade of white tungsten is not greatly improved. At this time, the rough selection foam product is selected by one blank and four times to obtain white tungsten containing WO ₃ 59.75% and recovery rate of 60.38%. Concentrate.

(3) Closed circuit test results

Due to the low grade of ore, the yield of ore dressing products obtained by flotation is small, and the molybdenum and tungsten concentrates are generally selected several times. In order to improve the test accuracy, the closed loop test uses 8L flotation machine for full float desulfurization and white tungsten floatation. The selected coarse and sweeping, the unit sample mass is 3kg. The process flow of the closed circuit test is shown in Figure 2, and the test results are shown in Table 3.

Third, the conclusion

(1) Molybdenum in a molybdenum ore flotation tailings mainly exists in the form of molybdenite. Because molybdenum ore has the characteristics of good natural floatability, as long as the molybdenum monomer dissociates or exposes part of the surface, it can be arrested. Close up. Tungsten is difficult to separate from the gangue because it is mainly composed of fine-grained inlays and is closely embedded with gangue. Therefore, the difficulty of this test is the improvement of the grade of scheelite concentrate. The key to the selection of white tungsten is the pulping process. Under the appropriate water glass modulus, the thick slurry adjustment and sufficient mixing time are the basis for the selection of qualified concentrates by white tungsten. The modulus determined in this test was 2.8.

(Ii) the tailings containing Mo0.05%, containing WO ₃ 0.112%, and Mo present in the primary molybdenite form, mainly tungsten is present in the form of scheelite, gangue sodium feldspar, quartz and calcite mainly . Therefore, the tailings have good development and utilization value.

(3)) The molybdenum concentrate grade is 48.50%, the recovery rate is 57.06%, and the scheelite concentrate contains WO by molybdenum-coarse-sweeping five fines, tailings re-selecting white tungsten, white tungsten, one coarse and one sweeping five fines. ₃ 56.45%, the recovery rate is 69.74%. The process structure is simple in structure, mature in process, and convenient for operation and application.

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