China is one of the world's molybdenum resources rich countries (0.212% Climax molybdenum mine) with the world's major molybdenum resources the United States and Chile (Sierra Gorda copper-molybdenum ore grade of 0.100% associated) compared to China's molybdenum deposit ore grade is significantly off low. For low-grade molybdenum ore, while ensuring the grade and recovery of molybdenum concentrate, it is also necessary to consider the comprehensive recovery of other valuable elements.
A low-grade fine fraction of molybdenum metal lead ore minerals molybdenite, galena, pyrite and other gangue minerals mainly quartz, feldspar, mica, tremolite, calcite and green clay Stone and so on. The main valuable elements are molybdenum and lead, and the grades are 0.079% and 0.45%, respectively. Other metal elements such as copper, zinc , iron, gold and silver have lower grades. The ore is mainly sulfide ore. The molybdenum is mainly in the form of molybdenum ore, accounting for 96.51% of the total molybdenum; the lead is mainly in the form of galena, accounting for 95.65% of the total lead.
According to the characteristics of the ore, the test finally determined the use of "molybdenum-lead mixed flotation-mixed coarse concentrate re-grinding molybdenum-lead separation" process technology, which can obtain better test indicators, molybdenum concentrate molybdenum grade 47.66%, molybdenum recovery rate 83.67%, the lead grade of lead concentrate is 62.56%, and the lead recovery rate is 85.69%.
First, the nature of the ore
(1) Analysis of chemical composition of raw ore
The main chemical composition analysis results of the ore are listed in Table 1.
Table 1 Analysis results of main chemical components of ore
chemical composition | Mo | Pb | S | Fe | Cu | Zn | As | CaF 2 |
Quality score | 0.079 | 0.45 | 2.28 | 4.31 | 0.024 | 0.038 | 0.0011 | 3.30 |
Continued Table 1
chemical composition | SiO 2 | Al 2 O 3 | CaO | MgO | Na 2 O | K 2 O | Au * | Ag * |
Quality score | 51.52 | 10.41 | 9.82 | 1.81 | 1.62 | 5.20 | 0.04 | 6.95 |
(II) Analysis of chemical phase of molybdenum and lead in ore
The chemical phase analysis results of molybdenum and lead are shown in Table 2 and Table 3, respectively. It can be seen that the oxidation rate of molybdenum and lead in the ore is relatively low, mainly sulfide ore.
Table 2 Results of chemical phase analysis of molybdenum
Table 3 Results of chemical phase analysis of lead
(3) Embedding characteristics of important minerals in ore
The metal minerals in the ore are mainly molybdenite, galena, pyrite, magnetite, pyrrhotite, followed by chalcopyrite, sphalerite, molybdenum, molybdenum, limonite, and red iron. Mine, Lanhui copper mine, porphyrite, copper blue, poisonous sand, white lead ore. Gangue minerals are mainly potassium feldspar, sodium feldspar, quartz, calcite, muscovite and biotite, chlorite and tremolite followed, apatite and the like.
The molybdenum ore is mostly scaly, leaf-like, slab-like or vein-like in size, and the distribution is extremely uneven. The particle size varies from 0.02 to 0.10 mm, and +74 μm accounts for 33.72%, and -74+20 μm. 38.22%, -20μm accounted for 28.06%. Partially related to gangue minerals, it is finely scaly and leaf-like in the gangue, and the degree of crystallization is poor, which is not conducive to the monomer dissociation of molybdenum ore; part along with minerals such as pyrite and magnetite The fractured fractures of the gangue minerals are filled and replaced; some are symbiotic or encapsulated with galena and sphalerite.
The galena is self-formed, semi-automorphic or granular, and has a close relationship with the gangue. It is partially symbiotic with or surrounded by pyrite, magnetite, sphalerite, and a small amount of galena. Wrapped with flaky molybdenum ore, a very small amount of galena is replaced by white lead ore, and the galena that is impregnated with fine particles is more difficult to dissociate from the monomer, which is not conducive to recycling. The particle size is 0.02 to 0.15 mm, +74 μm accounts for 58.81%, -74+20 μm accounts for 27.08%, and -20 μm accounts for 14.11%.
Second, the test results and discussion
According to the mineral composition of the ore and the nature of the ore, the process of the beneficiation principle is determined as the separation process of “molybdenum-lead mixed flotation-mixed coarse concentrate re-grinding molybdenum-lead separationâ€.
(1) Molybdenum rough selection collector dosage test
Kerosene is commonly used molybdenite flotation collectors, exploration tests showed that the mine molybdenum, lead easier to go up, roughing do not need to add auxiliary collector, you can only add kerosene. In the condition of grinding fineness -74μm accounting for 65%, kerosene is used as collector, and pine oil is used as foaming agent. Because kerosene has defoaming effect, in the kerosene dosage test, the amount of pine oil is also used. There are changes, and the test results are shown in Figure 1.
Figure 1 Test results of collector kerosene dosage
1-molybdenum grade; 2-molybdenum recovery; 3-lead grade; 4-lead recovery;
It can be seen from the test results of Fig. 1 that the best effect is obtained when the amount of kerosene is 100 g/t (at this time, the amount of pine oil is 50 g/t).
(2) Rough lime test
Lime is a commonly used inhibitor of pyrite . In order to fully suppress the floating of sulfur, the lime dosage test is carried out, and the results are shown in Fig. 2.
The results show that the addition of a small amount of lime can appropriately increase the recovery rate of molybdenum, and the amount of lime is preferably 500 g/t.
Figure 2 Results of rough selection of lime
(3) Grinding fineness test
Grinding is mainly to solve the dissociation of molybdenum ore from the ore in the ore. The grades of molybdenum and lead are low. In order to reduce the cost of ore dressing, flotation is required under coarser grinding fineness, and molybdenum ore is good. Natural floatability, for 0.15mm coarse quartz particles, can be floated when using 1% bare molybdenum ore with proper collector.
The ore grinding fineness test was carried out on the basis of optimizing the rough selection conditions. The test results are shown in Fig. 3. The test results show that when the fineness of grinding is more than 65%-74μm, the recovery rate of molybdenum and lead is not obvious. The finer the grinding fineness, the grinding cost will increase greatly. Considering the comprehensive grinding degree, the grinding fineness is 65. %-74 μm is preferred.
Figure 3 Grinding fineness test results
(4) Selected trials
The molybdenum-lead mixed concentrate also contains part of the undissociated molybdenum-lead continuum and the porphyrite. In order to better separate the molybdenum lead and obtain qualified ore dressing products, the molybdenum-lead mixed coarse concentrate must be reground. And then carry out molybdenum and lead separation.
1, regrind test
The regrind test is carried out with a selected molybdenum-lead mixed coarse concentrate. In order to obtain high-quality ore dressing products, an appropriate amount of lime is added during the selection. The test results show that the dosage is 100g/t, and the phosphorus konoke is used as the lead. For mineral inhibitors, the test procedure is shown in Figure 4 and the results are shown in Figure 5. The test results show that the molybdenum-lead separation and regrind fineness can be 80% -38μm.
Figure 4 Refining fineness test procedure for molybdenum-lead mixed concentrate
Figure 5 Re-grind test results
2, phosphorus Knox dosage test
The comparison test of different inhibitors of molybdenum and lead showed that the inhibitory effect of phosphonox was better. For this reason, the Phonon Knox dosage test was carried out, and the test results are shown in Fig. 6.
Figure 6 Test results of phosphorus and lead separation phosphorus Knox
As can be seen from the test results in Fig. 6, the amount of Phennox is 20 g/t.
(5) Closed circuit test
On the basis of the open circuit test, the test conditions were adjusted and optimized as necessary. In order to further improve the separation effect of molybdenum and lead, water glass, phosphonox, and BK510 combination agents are used as inhibitors of lead minerals. After the separation of molybdenum and lead, with the increase of the selection of molybdenum-lead mixed coarse concentrate, the phenomenon of lead drug removal is obvious. In order to ensure the lead recovery rate, a small amount of high-selective lead-selecting collector BK906 is added in the closed-circuit test. The results of the closed circuit test are shown in Table 4.
Table 4 Closed circuit test results
(6) Comprehensive recovery test of flotation tailings
In the closed-circuit test, the sulfur content of the flotation tailings (including sulfur in SO 4 2 - ) was 2.18%. In order to comprehensively recover the sulfur minerals, the tailings of the closed-circuit flotation were tested for sulfur. Xanthate is a common collector for pyrite, and it is the most easy to float in a medium with a pH of less than 6. In the test, a sulphur test was carried out with butyl xanthate as a collector. At 100 g/t, a sulfur concentrate having a sulfur content of 40.49% and a recovery rate (for the ore) of 57.01% can be obtained.
(7) Iron exploration test
In order to comprehensively recover valuable metals, a magnetic separation and iron exploration test was carried out on the floating sulfur tailings, and the “one-stage rough selection-re-grinding-selection†process was adopted, and the iron concentrate was reground to 80%-38 μm fineness. Iron concentrate with an iron grade of 66.45% and a recovery rate of 7.55% of raw ore is obtained.
Third, the conclusion
(1) Process mineralogical research shows that the metal minerals in the ore are mainly molybdenite, galena, pyrite, magnetite, pyrrhotite, etc.; gangue minerals mainly include potassium feldspar, albite, Quartz, calcite, muscovite and biotite. The main valuable elements in the ore are low content of molybdenum and lead, and their grades are 0.079% and 0.45%, respectively. Among them, the distribution of molybdenum minerals is uneven, the size of the inlay is extremely fine and the degree of crystallization is poor. The ore is mainly sulfide ore. The molybdenum is mainly in the form of molybdenum ore, accounting for 96.51% of the total molybdenum; the lead is mainly in the form of galena, accounting for 95.65% of the total lead.
(II) Beneficiation test research shows that the process technology of “molybdenum-lead mixed flotation-mixed coarse concentrate re-grinding molybdenum-lead separation†is adopted to suppress the separation effect of molybdenum and lead, and the combination of water glass, phosphorus Knox and BK510 is used. For lead minerals, the closed-circuit test indicators obtained are: molybdenum concentrate with molybdenum grade of 47.66%, molybdenum recovery of 83.67%, lead concentrate of lead grade of 62.56% and lead recovery of 85.69%.
(3) A comprehensive recovery test of closed tail flotation tailings is carried out to obtain a sulfur concentrate with a sulfur content of 40.49% and a recovery rate of 57.01%. The magnetic separation and iron selection test of the floating sulfur tailings can obtain 66.45% iron concentrate containing iron, so that the resources can be comprehensively utilized to achieve the purpose of comprehensive recovery.
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