(A) two features molybdenite flotation 1. luminance unnatural hydrophobic molybdenite molybdenite is naturally hydrophobic mineral that is mainly caused by natural hydrophobic nature of the crystal structure and bond. Comparison of nine non-ferrous metals rich ore ratios Metal name nickel antimony Zinc copper lead HG tin Tungsten molybdenum Yang mineral phase Original ore grade % 0.76 2.8 3.81 1.03 2.14 0.32 0.28 0.255 0.1 0.09 Concentrate grade % 4.67 19.9 51.4 22.7 55.8 29 44.3 67.7 46.3 46.4 Rich ore ratio 6.1 7.1 13.5 twenty two 26.1 90.6 158.1 265.5 424.8 515.6 (II) Study on the influence of ore properties on the quality of concentrates and the improvement of concentrate quality Beneficiation index of various types of ore deposits Deposit type Mine name Regrind Mineral processing index Molybdenum ore grade % Molybdenum concentrate grade % Molybdenum recovery rate % Gravel type Sanchuan Village, Luanchuan 87% of a 0.074 mm 0.234 56.55 98.34 Fine vein impregnation Jinduicheng 95% of a 0.034 mm 0.107 53.93 88.09 Transition zone type Xiaosigou 85% of a 0.053 mm 0.035 38.96 66.79 Carbonaceous shale type Tongshan 90% of a 0.074 mm 0.1096 42.57 83.79 It can be seen from the above table that the first two deposits can obtain high-quality molybdenum concentrate through the efforts of scientific research and production practice, and the recovery rate of molybdenum is also relatively high. China's four major molybdenum deposits belong to the first two types of deposits. In the medium and small molybdenum mines, the latter two deposits will also affect the quality of molybdenum concentrates throughout the country. At present, it has attracted the attention of the molybdenum selection workers, and has begun to study and has achieved certain results. Normal ore and crush zone ore dressing index Mine name Mine sample name Grinding fineness of 0.074 mm ( % ) Yield ( % ) Molybdenum ore grade ( % ) Molybdenum concentrate grade ( % ) Molybdenum recovery rate ( % ) Yang Jiazhangzi No. 8 skarn ore body 56 1.6 1.246 46.37 97.1 No. 9 crushing belt 52.35 0.4 0.524 7.06 57 Jincheng heap Dongpuzishan Ore 55 0.187 0.103 50.34 91.27 Dongbaozi crushing belt 55 4.74 0.061 0.63 49.13 Xiaosigou Quartzite No. 2 vein 65 0.132 0.084 53.94 84.99 Crushing belt 70 0.114 0.035 38.96 66.79 It can be seen from the above table that the crushed ore caused by geological structure seriously affects the quality of molybdenum concentrate and the recovery rate of molybdenum. It can be seen from the above figure that for fine-grained molybdenum ore, it must be re-milled in multiple stages to obtain satisfactory concentrate quality. Another example is the Sandaozhuang molybdenum mine in Luanchuan, which is a coarsely-embedded molybdenum ore with an average particle size of 64 microns, +74 microns for 70%, +20 microns for 92%, and mixed re-grinding, -74 microns for 87. % can obtain 56.56% of molybdenum concentrate, and the total recovery of molybdenum is 98.30%. Jinduicheng is a fine-embedded ore with an average particle size of 30 microns, -20 microns for 29.95%, and a three-stage regrind for mixing. The final fineness is -34 microns for 95%. Two middle mines can obtain 53-55% of molybdenum concentrate grade, and the molybdenum recovery rate is 86-88%. Customized Name Plates,Metal Name Plate,Custom Desk Name Plates,Metal Desk Name Tags Ningbo Best Channel Import & Export Co., Ltd. , https://www.btc-metal.com
The crystal structure of molybdenite is a standard layered structure. In the crystal structure of molybdenum ore, a molybdenum ion mesh is sandwiched parallel to the hexagonal stripe (between the two sulfide ion mesh faces of the bottom surface) such that the three mesh faces form a "structural layer", ie - molybdenum-sulfur layer. The molybdenum ions and the sulfur ions inside the structural layer are bonded by a covalent bond (chemical), so that the ion structures in the layer are dense. However, the structural layers are bonded together by a residual bond (dwarf bond), so the attraction between the layers is very relaxed.
When the molybdenite crystal is subjected to an external force, it is easy to be cracked along the residual bond between the structural layers, and becomes a parallel extremely complete dissociation surface, that is, the 0001 plane, and the crystal is in a sheet shape or a plate shape, which is molybdenum. The reason why the ore crystals can be completely dissociated. The dissociation surface of the ore is composed of a highly hydrophobic sparse atomic surface after the residual bond is broken. This is the reason why the surface of the molybdenite crystal has natural hydrophobicity causing natural floatability. The wet contact angle is measured. 75°. The Klemax Molybdenum Plant in the United States measured the 28-mesh (0.6 mm) portion of the ore in the ore, and the exposed surface of the 1% molybdenite in the quartz particles was able to float; in the 100 mesh (0.15 mm) portion. As long as there is an exposed surface of 0.2% molybdenite in the quartz particles, it is enough to keep floating.
2. The rich ore ratio of molybdenum ore The abundance of molybdenum in the earth's crust is not high. According to A•n·Vedagoradov data, the Clark value of molybdenum in the small shell is equal to 1.7×10 -4 % (1.7 g/ Ton).
Molybdenum ore is low in ore, generally 0.1 to 0.4%. However, the requirements for the grade of molybdenum concentrate for beneficiation are very high. Generally, MoS 2 is more than 90% in the world, and 75% in China.
In the usual ten major non-ferrous metal mineral production, Hui bonanza molybdenite than the maximum. The comparison of the rich ore ratios of nine major non-ferrous metals in China in 1981 is listed in the table below.
Although the floatability of molybdenum ore has the above two common characteristics, there are still obvious differences in floatability due to different ore-forming conditions, mineralization, geological processes and external influences.
1. Influence of deposit type on molybdenum concentrate quality There are four types of molybdenum deposits or copper-molybdenum symbiotic deposits currently under development in China. There are significant differences in the quality of molybdenum concentrates in various deposits. The first type is a skarn deposit, which is characterized by a higher ore grade of molybdenum and a larger crystal grain of molybdenite. This type of mineral is easy to choose, and the quality of molybdenum concentrate is good, such as the Sandaozhuang molybdenum mine in Luanchuan, Henan. The second type is the fine vein-disseminated molybdenum deposit. The characteristics of this type of deposit are: the ore grade of molybdenum is lower than that of skarn deposit, the embedding grain size of molybdenite is relatively fine, and the ore dressing index is not as good as skarn deposit. Such as the Jinduicheng molybdenum mine in Shaanxi Province. The third type is the copper-molybdenum transition zone ore. Due to the fault cleavage and development of the transition zone, the ore mud is seriously difficult to select and the ore dressing index is low. Such as the copper-molybdenum ore in the Shangsigou molybdenum mine in Hebei. The fourth category is a copper-molybdenum carbonaceous shale bed, such as Jiangsu receiving groove Copper Mountain copper molybdenum, copper-molybdenum ore body No. 2, the top and bottom corners of the carbonaceous siliceous rocks, metamorphic local coal was Dragon hornstone (carbonaceous shale). The quality of this type of ore molybdenum concentrate is very low, and it is difficult to achieve qualified molybdenum concentrate quality (45% with Mo). The ore dressing indicators for various types of deposits are listed below. [next]
2. Influence of geological structure on the quality of molybdenum concentrates The geological structure in the molybdenum deposits is often strongly affected by fractures and cleavage. In the middle of the domestic molybdenum mine, there are several crushing belts of different widths and sizes. Compared with raw ore, crushed ore has obvious differences in physical properties, degree of oxidation, crystallization, color, gloss and even chemical properties. Geological tectonic action often destroys the typical lamellar crystalline structure of molybdenite. The crystal lattice is often damaged, twisted, stretched, bent, and pulverized, causing the mine to change its original characteristics. The change of the crystal structure of the crushed molybdenum ore has seriously affected the quality of the molybdenum concentrate and also affected the beneficiation recovery rate of molybdenum.
The crushed ore has a large difference in material composition from the normal molybdenum ore. The ore is in the tectonic fracture zone, and the surrounding rock tends to undergo strong alteration. The gangue minerals are mainly flaky, fragile, easy-to-float granules with small fine-grained clay minerals and feldspars , quartz, mica , and such gangues are very easy to muddy, muddy gangue The mineral and a part of the fine molybdenite particles adhere to each other, making it difficult to separate the molybdenum-copper ore from such gangue, which seriously affects the quality of the molybdenite. The table below compares the mineral processing indicators of the normal ore and crushed ore in three mines.
3. Influence of the embedding grain size of molybdenum ore on the quality of molybdenum concentrate The embedding grain size of molybdenite has a great influence on the quality of concentrate. The quality of the concentrate depends to a large extent on the monomer-like deposit of the material. The granularity of the useful mineral inlay is not uniform, which requires multi-stage grinding before the selection. For example, the coarse concentrate of the Claymax Molybdenum Plant in the United States has been re-grinded five times in three stages. The low quality of molybdenum concentrate in China is related to insufficient regrind. [next]
The mixed concentrate at the site of Jinduicheng was re-grinded in the test chamber for several stages. After eight selections and different grinding fineness, the concentrate grade is shown in the figure below. 
On the contrary, for the coarse-grained Yangjiazhangzi molybdenite, over-crushing is unfavorable for flotation. This can be illustrated by the following test.
A single mineral of molybdenite is extracted from the Yangjiazhangzi molybdenum mine. After grinding to -180 mesh, the sieve was divided into four grades, respectively mixed with -200 mesh quartz, and floated under the same conditions to obtain a curve of the following figure.
4. Influence of carbon and easy-floating gangue on the quality of molybdenum concentrates During the molybdenum beneficiation process at home and abroad, due to the presence of carbon and easy-floating gangue ( sericite, kaolin , talc , montmorillonite, etc.), molybdenum is often affected. The quality of the mine makes the concentrate unqualified. Because the floatability of molybdenite is very similar to the floatability of these carbons, these carbons and gangues are easily incorporated into molybdenum concentrates, even if they are monomeric. For example, the ore processed by the Twins Butter Concentrator in the United States contains a large amount of talc and clay. The plant tried to suppress the talc and clay in the rough selection. Later, the mixture of lignosulfonate and lime was used to suppress the molybdenum anti-floating stone. The approach has only made progress.