introduction
Mineral resources are non-renewable resources. Since the beginning of this century, the value of mineral products has been rising, making low-grade ore, which was considered to be of little value in recycling, to be effectively mined and recovered. Flotation is the main method of beneficiation of molybdenite and scheelite . When the ore contains both of these useful minerals, the first molybdenum mineral is used, and the scheelite is selected. As an impurity element in scheelite concentrate, molybdenum requires floating molybdenum as much as possible before flotation of scheelite.
At present, there are mainly two processes for white tungsten flotation, namely "Peterlow method" and "731 oxide paraffin soap at room temperature flotation". The core technology of both processes is in the selection of operations. The former is characterized in that the coarse concentrate is added with a large amount of water glass under high temperature conditions for a long time of stirring to strengthen the inhibition of the gangue minerals, and then cooling and slurry selection. Because the latter is selected at room temperature, the water glass does not have the strong inhibitory effect like the “Petrov methodâ€, so it emphasizes the selectivity of white tungsten rough selection and pays more attention to the pulping process.
First, the nature of the ore
Tungsten ores is a typical skarn type scheelite, mainly metallic minerals scheelite, Ci molybdenite, pyrite and the like. Seq gangue diopside, garnet, followed albite, calcite and quartz. The multi-element chemical analysis and ore phase analysis results of the samples are shown in Tables 1 and 2, respectively.
Table 1 Multi-element chemical analysis results of samples
Table 2 Main mineral content %
The analysis of the main useful mineral content of the ore shows that the mineral composition in the sample is relatively simple, the tungsten is mainly scheelite, the molybdenum is mainly molybdenite, and the mineral content is 0.31% and 0.05%, respectively. Copper , lead and zinc minerals. Very few. The embedding characteristics of molybdenite and scheelite are characterized by fine molybdenum, coarser tungsten and lower grade. The gangue minerals are mainly silicate minerals, which may affect the quality of scheelite concentrates, mainly phosphorus .
Second, the process plan and process determination
The chemical analysis of the sample shows that the valuable recovering elements in the ore are molybdenum and tungsten, and the phase is single. The minerals co-existing with the scheelite are mainly silicate minerals. Although the molybdenite is not high in content and the inlay size is fine. However, it is not closely related to the scheelite. Therefore, it is determined that after a period of grinding, the whole flotation is removed to remove the sulfide ore. The sulfide ore mixed concentrate is re-grinded and then the molybdenum concentrate is selected. The full floatation and desulfurization tailings are 73 1 oxidized paraffin soap at room temperature. The flotation method recovers scheelite. Since the ore contains a small amount of apatite, it is necessary to adopt a phosphorus reduction process when selecting white tungsten.
Third, test results and analysis
The test uses the laboratory type XMQO 240mm×90mm cone ball mill , the XFD series single-tank type and the hanging tank type flotation machine. The flotation reagents all use the industrial flotation agent, and the water glass is explored and compared with the modulus of 2. 4. The sample was mixed by crushing and sieved, and the sample was weighed 1000 g. Due to the low grade of ore, the yield of molybdenum and tungsten coarse bubbles is small and inconvenient to select. Therefore, each continuous test unit in a small closed circuit test is divided into two stages, namely, full floatation desulfurization and white tungsten coarse, and continuous flotation in the sweeping stage. Three unit samples were obtained, and the obtained coarse concentrate products were combined into the next stage, namely, molybdenum, select and white tungsten.
(1) Full floatation desulfurization and molybdenum flotation test
The content of sulfide in the sample is small, and molybdenite is the main one, and the floatability of molybdenite is obviously superior to other sulfide minerals. Therefore, the principle of mixing molybdenum ore and remixing molybdenum is adopted. Program. The mixing float uses a two-rough one-sweep conventional flotation process. The crude concentrate was selected by a blank selection using a water glass + sodium sulfide combination inhibitor, and the ratio of the two was 1:5. The test results of the combined inhibitors are shown in Fig. 1.
Figure 1 Molybdenum selective combination inhibitor dosage test curve
(II) Results and analysis of white tungsten flotation test
1. White tungsten rough selection test
The tailings of floating sulfur use 731 oxidized paraffin soap and tar oil as collectors , sodium carbonate as a regulator, and water glass as gangue inhibitor for white tungsten rough selection. The amount of sodium carbonate and water glass tested are shown in Figure 2 and Figure 3, respectively.
Figure 2 Sodium carbonate dosage test curve
Figure 3 Water glass dosage test curve
The single factor test showed that no matter whether the sodium carbonate or the water glass is within the test dosage range, the tungsten recovery rate has little effect, and the coarse concentrate grade has obvious changes with the increase of the dosage. It is generally believed that there is a synergistic effect when sodium carbonate is mixed with water glass. Therefore, the factorization test is carried out centering on the amount of sodium carbonate 2000g/t and the amount of water glass 1800g/t. It is found that when the amount of sodium carbonate is 1 800 g/t. , the amount of sodium silicate 2000 g / sorting index is more preferably t, the available yield of 2.54%, containing WO 3 9.11%, 85.63% recovery of crude scheelite concentrate.
The sample contains WO 3 grade is lower, the gangue mineral is mainly silicate mineral, and the foam is not brittle when 731 oxidized paraffin soap is used as collector. Therefore, the tower with good foaming performance is selected. The oil is mixed with it, and the results of the collector dosage test carried out when the ratio of the ratio 731 oxidized paraffin soap: tar oil is 5:1 is shown in Fig. 4. When the amount of soap 731 oxidized paraffin 600g / t, the amount of tall oil available when containing 120g / t WO 3 9.08%, 85.89% recovery of crude scheelite concentrate, than single 731 oxidized paraffin soap (800 g / t) At the time of WO, the grade dropped by 0.24 percentage points, and the recovery rate increased by 2.26 percentage points.
Figure 4 collector test curve
2, 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. The inhibitor PY not only selectively inhibits phosphorus and phosphorus, but also adjusts the foam to make the selection process easier to control. Figure 5 is a test curve for the addition of PY + water glass composition (PY: water glass = 1:10). It is shown that when the amount of the composition is 1760 g/t, the white tungsten concentrate containing WO 3 65.71% and the recovery rate of 65.71% can be obtained by selecting 4 times. It is indicated that the combined inhibitors are not only used in a small amount, but also have a good selection effect, and the enrichment ratios of the four selection operations are 2.68, 1.62, 1.41 and 1.21.
Figure 5 Combined inhibitor dosage test curve
3. Closed circuit test and product analysis
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-circuit test is carried out according to the above methods. . The process flow of the closed circuit test is shown in Figure 6, and the test results are shown in Table 3. The analysis results of molybdenum and tungsten concentrate products are shown in Table 4 and Table 5.
Figure 6 closed circuit test process
Table 3 closed circuit test results%
Table 4 Chemical multi-element analysis of molybdenum concentrate
Table 5 Chemical multi-element analysis of white tungsten concentrate
The product analysis results show that the molybdenum concentrate meets the quality requirements of GB3200-82 Class II Class I; the scheelite concentrate meets the quality requirements of GB2825-81 Class I Class I products.
The particle size analysis results of the beneficiation products, the particles of WO 3 in the five-grain product of -0.45mm +0.30mm, -0.30mm +0.15mm, -0.15mm +0.105mm, 0.105 mm +0.074 mm and -0.074mm The recovery rates were 13.69%, 29.69%, 72.11%, 79.82% and 91.18%, respectively, indicating that the white tungsten flotation process used in this study is effective.
Fourth, the conclusion
(1) A skarn-type scheelite contains 0.012% Mo and 0.27% of WO 3 , and the ore structure is simple. Useful minerals with recycling value are mainly scheelite and molybdenite. The gangue is mainly composed of silicate minerals such as diopside and calcium aluminum garnet, and the harmful impurity mineral is apatite. It is a low grade easy to choose ore.
(2) The grade of molybdenum concentrate with full float desulfurization-floating molybdenum is 46.12%, and the recovery rate is 76.87%. The product quality meets the requirements of GB3200-82 Class II Class I; the desulfurization tailings float at room temperature at room temperature. The white tungsten solid concentrate is selected by PY and water glass combination inhibitor at room temperature to obtain a white tungsten concentrate containing WO 3 70.18% and a recovery rate of 85.31%. Its quality meets the quality requirements of GB2825-81 Class I Class I. The process structure is simple, the process is mature, and it is easy to operate and apply.
(3) The combination inhibitor used in the selection of white tungsten at room temperature overcomes the disadvantages of blistering, large circulation of medium ore, and difficulty in operation and control, and can effectively inhibit phosphorus-containing minerals. The process of acid leaching and dephosphorization of scheelite concentrate is eliminated.
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