New Process Test of Fine Particulate Molybdenum Iron Ore Dressing

China is one of the world's molybdenum resources rich countries, and Chile (Sierra Gorda copper-molybdenum ore grade of 0.100% associated) compared with the United States, the world's major molybdenum resources (Climax molybdenum mine grade of 0.212%), grade molybdenum deposits in China is significantly off low. The average grade of the deposit is less than 0.11%, accounting for 65% of the total reserves, of which less than 0.105% account for 10%, the medium grade 0.11%-0.12% deposits account for 30% of the total reserves, and the richer grades are 0.12%-0.13% deposits. The reserves account for 4% of China's total reserves, while the rich ore reserves with a grade of more than 0.13% account for only 1% of the total reserves. In order to economically and efficiently recover molybdenum and its associated elements, rationally utilize resources, reduce ore dressing costs, and enhance the competitiveness of molybdenum products in China, this study conducted a series of mineral processing experiments and research on a fine vein-extracted ore of a porphyry deposit. The ore properties and refractory factors were identified, and targeted measures were taken to obtain premium molybdenum concentrates and high-quality iron concentrates in accordance with GB3200-82.

First, the nature of the ore

    (1) Analysis of main chemical components of ore

    The main chemical composition analysis results are shown in Table 1. The valuable elements available for use are mainly molybdenum and iron.

Table 1 Analysis results of main chemical components

    As can be seen from Table 1, the main elements molybdenum metal recovery and grade iron was 0.12% and 5.87%, respectively, a relatively low content of other metals, silica rock-forming component, high aluminum content.

    (II) Phase analysis of major minerals

    The chemical phase analysis results of the main minerals are shown in Table 2.

Table 2 Results of phase analysis of molybdenum and iron minerals

The analysis results show that the oxidation rate of molybdenum is not high, and iron is mainly present in silicate minerals, and less iron is present in magnetite.

    (III) Analysis of the embedded relationship of major minerals

Silicate minerals and aluminosilicate minerals mainly minerals, ores; major metallic minerals molybdenite, magnetite, hematite lesser extent, ore, titanium, pyrite, chalcopyrite, galena and so on. The main gangue minerals as quartz, feldspar, amphibole, sericite, followed calcite, chlorite, sphene, fluorite, talc, rutile, carbon and the like.

    1. Molybdenum ore (MoS ₂ ): mainly in the form of lamellae, which are unevenly embedded in gangue or near-vein cracks, except for a part of coarse-grained aggregates and fine-grained single crystals embedded in gangue minerals. At home and abroad, most molybdenum ore is a medium-fine granule aggregate embedded in the gangue. Most of the molybdenum ore is between 0.010 and 0.147 mm, and a certain amount of fine-grained (-10 μm) molybdenum ore is embedded in the gangue. This part of the molybdenite can only be fully dissociated by fine grinding, which is not conducive to molybdenum. Recycling. The molybdenite in the ore is closely related to the inlay of quartz, chlorite, feldspar and calcite.

    Magnetite (Fe ₃ 0 ₄ ): Most self-formed, semi-automorphic grains are embedded in gangue minerals, and most of the magnetite is impregnated with granules and fine particles in gangue minerals. Occasionally, hematite is replaced by magnetite, and a small amount of fine-grained molybdenum ore is associated with magnetite. A small amount of magnetite is closely symbiotic with pyrite. The magnetite has a particle size of 0.005 to 0.4 mm.

Second, the program is determined

    The target metal mineral in the ore is molybdenum ore. The content of other metal sulfide minerals is very low, and there is currently no recovery value. The flaky sericite, layered talc, carbonaceous materials, etc. in the ore and the sulfide ore such as copper and lead will affect the quality of the molybdenum concentrate and need to be dispersed and inhibited; the ore also contains a small amount of magnetite which can be comprehensively recovered.

    (1) Analysis of difficult points in molybdenum beneficiation technology

    The difficulty in selecting the ore molybdenum is mainly to improve the floatability of some molybdenum ore and to reduce the problem of the inclusion of molybdenum concentrates such as easy-floating gangue minerals and chalcopyrite and galena. Due to the occurrence of ore body fracture and fault displacement during the mineralization process, the crystal form of some molybdenum ore changes and the floatability decreases. Similarly, some molybdenum ore has a film-like structure, which is excessively pulverized and muddy, and is easily lost during the sorting process; the molybdenum ore is wrapped in the gangue mineral and is not easily dissociated; affecting the grade of molybdenum concentrate The biggest factor is the structure and properties of gangue minerals. The ore contains a large amount of muddy silicate, aluminosilicate and sulfate minerals, and also contains flaky sericite, layered talc, granular fluorite, etc. These gangue minerals and muddy clay Even the slime-like silicate minerals will affect the flotation process of molybdenite, and it will easily be mixed into the molybdenum concentrate, which will reduce the grade of molybdenum concentrate. These technical difficulties and influencing factors are directly related to the formulation of the beneficiation plan. And process structure, pharmaceutical system and process parameters optimization.

    (2) Dissociation degree of minerals under different grinding fineness

    The dissociation degree of molybdenum minerals under different grinding conditions is as follows: molybdenum ore monomer accounts for 69.9% when grinding fineness is 60%-74μm, 79.2% for 65%-74μm, and 83.3% for 70%-74μm. It accounts for 86.6% at 80%-74μm and 87.8% at 90%-74μm. It shows that under the coarse grinding fineness, the dissociation degree of the valuable mineral molybdenite monomer is low, the finer the grinding fineness, the higher the dissociation degree of the monomer, but the grinding cost is high.

    The results of dissociation of magnetite under different grinding fineness indicate that even when the fineness of grinding is -74μm, 90%, the dissociation degree of magnetite in ore is still low, and the monomer dissociation degree is low. About 55%.

    (3) Initial determination of the test plan

    The Donggou molybdenum deposit belongs to a single molybdenum deposit, and its ore technical processing performance shows complexity. The overall beneficiation scheme adopts the flotation scheme commonly used at home and abroad, and different operation methods are adopted in the process flow:

    1) In order to reduce the cost of mineral processing, rough grinding and flotation should be used as much as possible. Due to the low degree of dissociation of molybdenum ore in the coarser grinding fineness, a part of the continuous body exists, and the combined collector is used in the flotation to exert the synergistic effect and strengthen the flotation of the molybdenite orthoplasts to obtain A coarse concentrate with the highest possible recovery of molybdenum.

    2) Due to the existence of a large number of continuous organisms in the molybdenum coarse concentrate, the refinement of the concentrate is established to make the molybdenum ore have a higher degree of dissociation, which provides a guarantee for obtaining high-quality molybdenum concentrate.

    3) Develop or select dispersants and inhibitors suitable for dispersing and inhibiting flaky sericite, layered talc and a large amount of silicate, aluminosilicate and sulfate minerals to improve the grade and quality of molybdenum concentrate.

    4) Select effective inhibitors for sulfide ore, pyrite, galena and other sulfide minerals to ensure the quality of molybdenum concentrate.

    5) The size of magnetite inlay is mainly composed of fine particles and fine particles. It is difficult for magnetite to achieve better monomer dissociation under rough grinding conditions. In order to reduce the cost of iron production, the iron concentrate is re-grinded as much as possible. the amount.

    According to the above analysis, the proposed beneficiation test scheme is a coarse grinding flotation tailing one molybdenum coarse concentrate re-grinding one flotation tailings magnetic separation iron-iron coarse concentrate multi-stage re-grinding more than one selection.

Third, experimental research

    (1) Application of coarse grinding and tailing and combined collector

    Due to the low grade of molybdenum ore, in order to reduce the cost of ore dressing, it is necessary to float under a coarser grinding fineness. Molybdenum ore has good natural floatability. For 0.15mm coarse quartz particles, it can float smoothly when using 1% bare molybdenum ore with proper collector, so in the molybdenum ore flotation, even if Lean contiguous organisms, as long as there is exposed molybdenite and can be floated smoothly with suitable collectors, this opens up the possibility of coarse grinding and throwing of molybdenum ore.

    When coal is selected from molybdenum crude oil in an amount of 100g / t, the combination is mixed oil collector (100g / t), when BK310 (60g / t), different conditions of grinding fineness the comparative results shown in Figure 1.

    The test results in Figure 1 show that the combined collectors play a synergistic effect on the absorption of molybdenum and its continuum, and a higher recovery rate of molybdenum can be obtained under coarser grinding fineness. It is guaranteed to reduce the cost of mineral processing and achieve rough grinding and tailing.

    (2) Inhibitor test

    In order to select qualified molybdenum concentrate from coarse concentrate containing a large number of connected organisms, it must be re-ground to make the molybdenite in the coarse concentrate completely dissociated from the molybdenite and galena, chalcopyrite and yellow. Separation of sulfide ore and gangue minerals such as iron ore provides the possibility.

    Due to the wide variety of gangue minerals in ore and their different properties, the use of a certain mineral inhibitor does not achieve multiple inhibitory effects. Therefore, various inhibitors have been added to the molybdenum selection operation to achieve multiple inhibition effects. After the re-grinding of molybdenum coarse concentrate, the amount of water glass is 20g/t, the amount of mixed oil is 12g/t, the amount of pine alcohol oil is 4g/t, the test results of copper inhibitor thioglycolate are different. Figure 2 shows that thioglycolic acid has a good inhibitory effect on bismuth minerals and can effectively reduce the copper content in molybdenum concentrate.

    (III) Comprehensive recovery test of magnetite

    The ore also contains a small amount of magnetite. The size of the inlay is fine and uneven, and the -43μm particle size accounts for 70% of the total. Even when the grinding fineness is -74μm, 90%, the dissociation degree of magnetite Only 55%, in order to reduce the cost of iron selection, reduce the amount of iron coarse concentrate re-grinding, the implementation of magnetic separation iron coarse concentrate multi-stage re-grinding more than one selection. The test results of iron selection under different magnetic field strengths of molybdenum flotation tailings are shown in Fig. 3. When the magnetic field strength is 94.4 kA/m, the test results of iron coarse concentrate under different regrind fineness are shown in Fig. 4.

    The test results show that with the increase of magnetic field strength, the recovery rate of iron ore concentrate in flotation tailings has been increasing, which further proves that the magnetite inlay has finer grain size; when the iron coarse concentrate regrind reaches 95%- At 25μm, the grade of iron concentrate can reach more than 64%, the recovery rate of operation is over 46%, the yield of flotation tailings is 1.65%, the recovery rate of flotation tailings is 18.34%, and the recovery rate of magnetite is 16. 78.61%, indicating that to obtain high-grade iron concentrate, the full monomer dissociation of magnetite is the key.

    (4) Expanding the test

    For the ferromolybdenum type ore, the first flotation magnetic separation sequence is adopted. The molybdenum flotation principle process is a rough grinding tailing, molybdenum two-stage re-grinding, eight times selection, adding coarse concentrate re-grinding and scrubbing technology in two selection processes, obtaining high-quality molybdenum through multiple selections. Concentrate product creation conditions; due to a certain amount of slime in the molybdenum coarse concentrate, there are some gangue minerals such as pyrite and sericite which can be floated well. After regrind, the slime will be further increased. Affecting the next step in improving the grade of molybdenum concentrate, so set up a selection of operations before regrind. In order to reduce the re-grinding amount of coarse concentrate, ferromagnetic selection adopts a multi-stage grinding-multi-stage magnetic separation process scheme.

    The molybdenum flotation adopts a rough grinding and tailing, molybdenum two-stage re-grinding, eight selection principle process, ferromagnetic selection, rough selection, two-stage re-grinding, three-time selection, and fineness of 65%-74μm in the ore grinding. The test indicators for continuous stable operation for 72 hours are: 0.12% of the molybdenum grade, 52.62% of the molybdenum concentrate grade, and the recovery rate of 85.88%. The ferromagnetic selection index is 6.16% of the ore grade and 62.23% of the iron concentrate grade. The total iron recovery rate is 18.56%, and the magnetic iron recovery rate is 76.61%.

Fourth, the conclusion

    1) Using the floatability of molybdenum ore, by using a combination of collectors, strengthening the flotation of molybdenum ore and its continuum, maximizing the recovery of molybdenum in the rough section to ensure the recovery of molybdenum, achieving rough grinding and tailing Reduce the cost of mineral processing.

    2) Set up the re-grinding operation of molybdenum coarse concentrate, add coarse concentrate regrind and scrub technology in the selection process, and select copper high-efficiency inhibitor to ensure high molybdenum dissociation degree, effective It inhibits sulfide minerals such as chalcopyrite and guarantees the quality of molybdenum concentrate.

    3) Using the first floating magnetic method, the molybdenum concentrate grade is 52.62%, the recovery rate is 85.88%, the iron concentrate grade is 62.23%, and the magnetic iron recovery rate is 76.61%. The special grade molybdenum conforming to the standard GB3200-82 is obtained. The concentrate and high-quality iron concentrate have found a new way for the porphyry fine vein disseminated ore beneficiation process, which provides a reliable technical basis for the development and utilization of the molybdenum ore.

Johnson screen is a v-type wire welding filter element developed by Johnson Company in order to solve the problem of solid-liquid separation. The surface wire is connected together with the support rods by welding.