Experimental study on ore dressing of a lead oxide zinc ore

There is a large number of low-grade, lead and zinc oxide refractory ores. In view of the complex mineral composition of lead oxide zinc ore, serious weathering, muddy, and difficult dissociation of mineral monomers, the ore dressing test was carried out to rationally develop and utilize such ore.

First, the nature of the ore

The main ore mineral is white metal lead, lead alum, calamine, brown iron ore, hematite, the main gangue minerals are quartz, calcite, dolomite and so on. The results of multi-element analysis of ore chemistry are shown in Table 1. The results of lead and zinc phase analysis are shown in Table 2. The lead and zinc grades were 2.60% and 4.26%, respectively. The phase analysis shows that the lead mineral is mainly white lead ore and a small amount of lead vanadium ; the zinc mineral is magnesite and a small amount of heteropolar ore. The ore is more oxidized.

Table 1 Multi-element analysis results of ore chemistry

Table 2 Results of ore phase analysis

Second, the choice of test plan

A preliminary exploration experiment was conducted on the characteristics of the ore. The test results show that the lead-zinc minerals in the ore can be recovered by the flotation flotation method. The desilting flotation can not effectively improve the flotation index. On the contrary, it loses a lot of fine-grained lead-zinc ore, because the white lead in the fine mud has Good floatability, dephosphorization before flotation will reduce the lead recovery rate, and the effect of slime can be reduced by adding a modifier. In the case of no mud removal, a good index can be obtained by flotation using a sulfurization-amine method.

Third, the test results discussion

(1) Lead rough selection test

1. Effect of dispersant dosage on flotation of lead minerals

According to the condition test results, it is determined that the grinding fineness is -0.074 mm and accounts for 80%. The ore mud is relatively serious, and it is necessary to add a dispersing agent to disperse the pulp to eliminate the influence of the slime. In the case of slurry pH=9, sodium sulfide dosage 2kg/t, zinc sulfate and sodium sulfite (mass ratio 1:1) mixed dosage 1000g/t, ethyl sulfide nitrogen + butyl yellow dosage 80g/t, dispersant water glass dosage The test results of the impact on lead ore flotation indicators are shown in Figure 1.

Fig.1 Effect of water glass dosage on lead flotation index

It can be seen from Figure 2 that the addition of water glass can improve the lead ore recovery and lead recovery rate; as the amount of water glass increases, the lead concentrate grade increases, but the lead recovery rate decreases. It shows that water glass has a better dispersion effect and can significantly improve the lead ore flotation index. However, when the dosage is too large, it has a certain inhibitory effect on lead minerals.

Figure 2 Effect of sodium sulfide dosage on lead ore flotation index

2. Effect of sodium sulfide dosage on flotation of lead minerals

The vulcanization effect of lead oxide minerals directly affects the selection index: the amount of sodium sulfide is small, and the vulcanization effect is not satisfactory; if the amount of sodium sulfide is too large, it will inhibit lead ore and reduce the lead recovery rate. It can be seen from Figure 2 that as the amount of sodium sulfide increases, the grade of lead crude concentrate decreases slightly, which may be caused by increased alkalinity and increased viscosity of the slurry. The recovery rate of lead crude concentrate increased with the increase of sodium sulfide dosage within a certain range. However, when the amount of sodium sulfide was too large, the recovery rate of lead crude concentrate decreased. Considering comprehensively, the amount of sodium sulfide is suitably 4000g/t.

3. Effect of inhibitor dosage on flotation of lead minerals

The effect of water glass dosage is 400 g/t, sodium sulfide dosage is 4 kg/t, ethyl sulphate nitrogen + butyl yellow is 100 g/t, and the effect of sulfuric acid and sodium sulfite (1:1) on the zinc grade of crude lead concentrate The result is shown in Figure 3.

Fig. 3 Effect of zinc sulfate + sodium sulfite (1:1) on the flotation of lead ore

It can be seen from Fig. 4 that with the increasing amount of zinc sulfate and sodium sulfite, the zinc grade in the lead concentrate is gradually decreased; after the amount of the mixture is increased to 800 g/t, the zinc recovery rate and grade change are not obvious. This is mainly due to the fact that the ore contains more mud and mechanical inclusions. Therefore, a suitable amount of the mixture of zinc sulfate and sodium sulfite is preferably 800 g/t.

4. Selection and dosage of collector

In view of the complex nature of the ore, there are some defects in the flotation performance of the single agent. Therefore, the combined agent is used as a collector, and several combined collectors are compared. The combined collectors were ethyl sulphide + xanthate, xanthate + butyl xanthate, butyl xanthate + butyl ammonium black drug, and the mass ratio of the two collectors in each combination was 1:1. The test results showed that the lead recovery rate was the highest with the combination of ethyl xanthate and butyl xanthate, reaching 64.88%, and the lead grade was also 18.1%. The comprehensive index was good. The effect of the amount of mixed agent on the flotation index is shown in Figure 4. It can be seen that the optimum dosage of the combination of the xanthate and the diced yellow drug is 120 g/t.

Figure 4 Effect of collector dosage on lead flotation index

(2) Effect of zinc rough selection conditions on flotation

Butyl xanthate in an amount 200g / t, 2 # oil usage 60g / t conditions, influences of the amount of activator copper sulfate flotation zinc oxide, test results are shown in Fig. It can be seen that as the amount of copper sulfate increases, the zinc grade decreases, but the recovery rate increases; when the amount of copper sulfate is increased to 600 g/t, the zinc recovery rate is not significantly increased. Therefore, the amount of copper sulfate was determined to be 600 g/t.

Figure 5 Effect of activator dosage on zinc flotation index

(3) Closed circuit test

Lead flotation conditions: adjust the slurry with sodium carbonate to pH=9, water glass dosage 400 g/t, sodium sulfide dosage 4 kg/t, mixed yellow medicine dosage 120g/t; zinc flotation condition: copper sulfate dosage 600g/ t, butyl yellow medicinal amount 200g / t, 2 # oil dosage 60 g / t. The small closed-circuit test process is a rough one-sweep three selection; the lead and zinc feed grades are 4.26% and 2.60, respectively. The yield of lead concentrate is 45.23%, the recovery rate is 73.51%; the grade of zinc concentrate is 40.56%, and the recovery rate is 72.21%.

Fourth, the conclusion

The mineral composition of lead oxide zinc ore is complex, weathering and muddy are serious, and the dissociation of mineral monomers is difficult. The use of sulfide flotation can effectively enrich lead and zinc minerals. Ethyl xanthate + Dinghuang has good collection ability and selectivity for lead minerals. The proper amount of water glass has good dispersion effect and can significantly improve the lead ore flotation index; zinc sulfate + sodium sulfite is a good inhibition of zinc. The agent, copper sulfate can play a role in activating zinc ore and increasing the flotation index of zinc.

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