Experimental study on flotation separation of fluorite and barite

As a strategic mineral, fluorite is widely used and plays an important role in the economic construction of a country. China's fluorite ore reserves are among the highest in the world, most of which are associated ore, often associated with quartz , calcite , barite and sulfide minerals. At present, flotation is generally used to enrich fluorite, especially when sorting high-purity fluorite ore powder, which is separated by flotation. Non-metallic mineral fluorite Comparative buoyant minerals of quartz as a main gangue fluorite - Quartz ore consisting simple because, under normal circumstances as a slurry adjusting agent, sodium carbonate, sodium silicate gangue as inhibition The agent, oleic acid as a collector can achieve the desired sorting effect. However, in the case of fluorite ore containing a certain amount of barite, carbonates and polymetallic symbiotic minerals, it is difficult to obtain high quality fluorite powder. Because the two minerals, fluorite and barite, are not only similar in mineral surface properties and chemical properties, but also the collectors and inhibitors on both mineral surfaces behave very similarly and have good floatability. In order to achieve effective sorting, how to overcome the difference between the two, to find a selective inhibitor of barite and the combination of agents is the key to its successful separation.

In order to develop local fluorite ore resources, a mining development company entrusted the Maanshan Mine Research Institute of Sinosteel to conduct a beneficiation process project for ore containing fluorite-barite. According to the contract requirements, the laboratory beneficiation index is expected to achieve CaF ₂ ≥ 98%, SiO ₂ ≤ 1.0%, and increase the recovery rate of fluorite as much as possible. Based on the principle of high efficiency and simplicity, combined with the current actual conditions of fluorite beneficiation, the whole flotation process is adopted, and the beneficiation process and process parameters are determined based on the research results. Through a large number of experimental studies, we have found a inhibitor MKF-1 with selective inhibition of barite, thus achieving the separation of fluorite and barite minerals. Using a rough five-selection ore process, fluorite concentrate can be obtained in the case of grinding fineness -0.076mm 82%, raw ore containing CaF ₂ 83.23%, BaSO ₄ 14.90%; CaF ₂ 99.35 %, BaSO ₄ 0.06%, SiO ₂ 0.071%, recovery rate 85.43% test results. The trial achieved the desired goals.

First, the nature of the ore

The fluorite and barite in the ore of this mine are co-owned together. According to the volume percentage of fluorite and barite, they can be divided into fluorite-barite type and barite type. Both have both. In the same vein, the two ores are characterized by their growth and decline. Many characteristics indicate that fluorite is produced in the middle of the vein. The veins are mainly vein-like, with a length of several hundred meters and a thickness of 1.0-10.0m, generally 2.0-4.0m. The boundaries of the surrounding rock are clear. The intact ore is white in color, high in quality and low in impurity content. Due to weathering, leaching and dip dyeing, the broken ore is brownish yellow and its whiteness is seriously affected. The ore industry type of this test is fluorite-barite type, the ore mineral is mainly fluorite, followed by barite. Fluorite (barite) is white, with a brownish yellow color, and the joints are more developed. The beneficial components have vitreal and silky components. Less gangue minerals, harmful components are mainly pyrite and some clay minerals, silica and other minerals. The ore has granular, slab-column structure, block, strip and agglomerate structure. The surrounding rock erosion has fluorite, recrystallization, petrochemical and a small amount of silicification.

    (1) Sample preparation

The test ore sample is provided by Party A and the total amount is about 200Kg. The ore is crushed to 0~2mm, and most of it is used as a laboratory ore dressing mine, except for a small portion of spare. The ore was analyzed by analysis of CaF ₂ 83.23% and BaSO ₄ 14.90%.

(II) Multi-element analysis of raw ore

Table 1 Multi-element analysis results of ore (%)

(3) Separation of 0~2mm grain size of raw ore

Table 2 Results of sieve analysis of 0~2mm grain size of ore (%)

Second, the beneficiation test

Since the ore belongs to the fluorite-barite type, its main components are fluorite and barite, and other harmful impurities are low. The ore dressing research mainly solves the separation between CaF ₂ and BaSO ₄ . The flotation test uses floating fluorite to suppress barite. The main factors affecting flotation are the test: grinding fineness, flotation temperature, flotation concentration, pulp pH, collector dosage, inhibitor type and dosage, etc. . According to the preliminary test results, the flotation temperature is determined to be 30 ° C, the slurry concentration is 30%, the pulp PH 9. 0 (Na ₂ CO ₃ 500 g / t, Na ₂ SiO ₃ 500 g / t) collector T-69 480 g / t, etc. Conduct a verification test. Mainly examine the impact of grinding fineness and different inhibitors on flotation indicators.

(1) Test equipment, flotation process conditions and flotation reagents

1. Test equipment: XMQ-67 type 240X90 cone type ball mill , MFD-63 type tank flotation machine 0.5L and 0.75L.

2. Flotation process conditions: the original ore grinding concentration is 66.7%, the flotation slurry concentration is 30.0%, and the flotation slurry temperature is 30 °C.

3. Flotation agent: The regulator is Na ₂ CO ₃ , the collector is T-69, and the inhibitors are Na ₂ SiO ₃ , MKF-1, MKL-1, MKD-1. The above-mentioned agents were used in addition to T-69 for the addition of the stock solution, and the others were used in a concentration of 2%.

(2) Grinding fineness test

Under the pharmaceutical system of Na ₂ CO ₃ 500g/t, Na ₂ SiO ₃ 500g/t, T-69 480g/t, the grinding fineness test was carried out by one rough selection.

Table 3 Grinding fineness test results

The results of grinding fineness test show that with the improvement of grinding fineness, the concentrate yield, grade and recovery rate increase gradually. When the grinding fineness is -0.076mm82%, the concentrate grade can reach 90.65%, and the recovery rate It is 95.49%. The grinding fineness of this test was determined to be -0.076mm82%

Third, different types of inhibitors experimental research

According to the results of the rough test, the other conditions remain unchanged when the inhibitor is studied, namely: grinding fineness -0.076mm82.0%, flotation temperature 30 °C ± 1, flotation concentration 30.0%; adjusting agent Na ₂ CO ₃ 500g/t, commonly used inhibitor Na ₂ SiO ₃ 500g/t, fluorite collector is the national invention patent product T-69 developed by our institute. The effects of inhibitors MKF-1, MKD-1, MKL-1, their combinations and dosages on fluorite selection indicators were studied and systematically studied.

(1) Inhibitor MKF-1 dosage test

The test procedure is shown in Figure 1, and the test results are shown in Table 4. It can be seen from Table 4 that as the amount of MKF-1 is gradually increased from 500 g/t, the concentrate grade is gradually increased, and the recovery rate is slowly decreased. When the dosage of MKF-1 is 0g/t, the concentrate grade is only 94.20% and the recovery rate is 60.05%. When the dosage of MKF-1 is 1250g/t, the concentrate grade can reach 99.65% and the recovery rate is 71.26%. Compared with the two, the concentrate grade is 5.45 percentage points higher, and the recovery rate is 11.21 percentage points higher. It proves that the MKF-1 inhibitor has a good selective inhibition effect on the separation of fluorite and barite. The better the suppression effect. It is more appropriate to consider 1000g/t for the comprehensive consideration of the test.

Figure 1 Inhibitor MKL-1 dosage test procedure

Table 4 MKF-1 dosage test results

(2) MKF-1 and MKD-1 combination test

Table 5 MKF-1, MKD-1 combination test results

Both MKF-1 and MKD-1 are inhibitors, and their performance is mainly distinguished by the ability to inhibit minerals. The former has good selectivity and the latter has strong inhibition ability. The test results are shown in Table 5. The test results show that when the dosage of MKF-1 is 1000g/t, the concentrate grade increases with the increase of MKD-1 dosage, but the yield and recovery rate decrease gradually. It shows that MKD-1 has strong inhibition ability, and the combination with MKF-1 is not particularly ideal for the selection of this ore sample.

(III) Selection test of inhibitors MKL-1 and MKD-1

The test used NaOH (500 g/t) as a regulator, MKL-1 and MKD-1 (600:200 g/t) as inhibitors, and T-69 (480 g/t) as a collector. The test flow is shown in Figure 2. The test results show that the above-mentioned pharmaceutical system can obtain 98.52% concentrate grade and 73.07% recovery index.

Legend: Original ore

Figure 2 Inhibitor MKL-1, MKD-1 combination test procedure

(4) Comparison of rough selection and MKF-1 drug selection plus MKF-1 and MKD-1 combinations

Table 6 MKF-1 drug selection plus MKF-1, MKD-1 combination comparison test results

The test used a rough five fine process. The test results are shown in Table 6. It can be seen from Table 6. Under the same crude drug system, a small amount of MKF-1 and MKD-1 combination agents can be added to the selection, which can increase the concentrate grade by 0.54 percentage points and increase the recovery rate by 1.76 percentage points. It is indicated that the addition of a small amount of agent in the selection is beneficial to improve the quality and recovery of the concentrate.

(5) Selective open circuit test for different inhibitors

In the ore grinding fineness -0.076 mm accounted for 82%, flotation and coarse five fine, using the combination of inhibitors MKF-1, MKD-1 and MKL-1 can achieve 98% concentrate grade, recovery rate of 70% or more Sorting effect. MKF-1 has a good selective inhibition effect. The selected open circuit test can obtain a flotation index of 99.32% concentrate grade and 72.19% recovery rate. The combination of the inhibitors MKD-1 and MKL-1 also has a certain selective inhibition effect. The selected test can achieve a concentrate grade of 98.50% and a recovery rate of 73.07%. The combination of a small amount of MKF-1 and MKD-1 in the selection is beneficial to the improvement of concentrate grade and recovery rate.

The results of the inhibitor selection test are shown in Table 7.

Table 7 Selected test results of different inhibitors

(6) Closed circuit test

The closed circuit test was conducted on the basis of a selected open circuit test. The grinding fineness is -0.076mm82%, and the process adopts a coarse five fine. The agent is Na ₂ CO ₃ as a regulator, Na ₂ SiO ₃ , MKF-1 and MKL-1 MKD-1 are inhibitors, and T-69 is a collector. The closed-circuit test mainly solves two problems: the impact of the combination of the return location of the mine and the inhibitor on the selection index. In the experiment, two processes were mainly investigated: first, the centralized return of the mine to the rough selection, and second, the return of the middle mine to the previous operation. In the pharmaceutical aspect, the effects of the combination of inhibitors MKF-1, MKL-1 and MKD-1 on the selection index were investigated. MKF-1 medium mine return to rough selection closed circuit test number quality process is shown in Figure 3MKF-1 mine sequence return previous operation closed circuit test number quality process see Figure 4 closed circuit test results see Table 8

Table 8 Summary of closed-circuit test results

Figure 3 MKF-1 mine concentrated return rough selection closed circuit test number quality process

legend: legend:

Figure 4 MKF-1 mine sequence returned to the previous job closed circuit test number quality process

In the closed-circuit test, the mine returning point adopts two process structures: centralized return to rough selection and sequential return to the previous operation. The difference in the sorting effect is not large, and all the CaF ₂ grades can be obtained more than 99%, and the recovery rate is more than 85%. index of. Both process structures have their advantages and disadvantages: the centralized return process of the middle mine is complex, requires more equipment, and is easy to lead to unstable production process, causing fluctuations in concentrate index; the process of returning the sequence of the mine is simple, the production process is stable, and the concentrate The grade is easy to guarantee. Therefore, considering the comprehensive consideration, it is more appropriate to return the previous operation sequence to the middle mine. In terms of pharmacy: the inhibitor MKF-1 has a good selective inhibition of barite minerals, which improves the floatability of fluorite to some extent. Regardless of the process used, the application of the agent can achieve more than 98% of the CaF _{2 in the} concentrate. The closed-circuit test results of the inhibitors MKL-1 and MKD-1 were not satisfactory. MKL-1 and MKD-1 have a certain selective inhibition effect on barite minerals, but MKL-1 can not completely inhibit the barite from floating up, and when the amount of MKD-1 is larger or smaller, the selectivity will be lost. Therefore, the reasonable ratio of the two inhibitors is the key to the success of the test.

Fourth, the conclusion

1. Since the ore of this test belongs to the type of fluorite-barite, its main components are fluorite and barite, and other harmful impurities are low. The beneficiation study mainly addresses the separation between CaF ₂ and BaSO ₄ . Therefore, the search for inhibitors with high selective inhibition of barite is the key to the success of this test.

2. For the fluorite ore beneficiation of a mineral development Co., Ltd., the grinding fineness of -0.076mm accounts for 82% of the crude flocculation process, and MKF-1 is used as the inhibitor. The final test result is CaF ₂ concentrate. The rate is 71.54%, the grade is 99.35%, the SiO ₂ content is 0.071%, the BaSO _{4 is} 0.06%, and the recovery rate is 85.43%. All test indicators have reached the contract requirements.

3. The test results show that the two process structures returning to the rough selection and the middle mine returning to the previous operation have little effect on the selection index. It is recommended to use the grinding-one-five-finish mine sequence to return to the full-floating process of the previous operation.

4. Inhibitors MKF-1, MKL-1 and MKD-1 have good selective inhibition effects on barite minerals.

5. The test data shows that the fluorite content in the tailings is high, and most of the barite remains in the tailings. It is recommended to increase the sweeping selection after rough selection to minimize the loss of useful minerals. The comprehensive recovery of spar is conducive to the comprehensive recycling of minerals.

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