For rough concentrate directly from the living body contains a large selection of qualified molybdenum concentrate is obviously impossible. It must be re-ground to dissociate the molybdenum ore in the coarse concentrate to select high-quality molybdenum concentrate.
The grain size of molybdenum ore in each deposit and ore body is different, and the reasonable regrind fineness is also different.
The molybdenum ore in the Claymax molybdenum ore has a very fine particle size (fine to 2 μm), and the dissociation degree of the molybdenum ore in different sizes of molybdenum ore is shown in Fig. 1.
Figure 1 Monomeric dissociation and particle size of Claymax molybdenite
It can be seen from the figure that in order to produce a molybdenum concentrate containing more than 54% molybdenum (including MoS 2 greater than 90%), a fine grinding is required. The fine concentrate produced by rough grinding is about 80%-65 mesh, and after three times of three-stage gravel grinding, the fineness of tailings is about 80%-325 mesh, while the smelting grade molybdenum The fineness of the concentrate is 80%-20μm.
JINDUICHENG molybdenum ores in different size fractions of the monomers of molybdenite degree of dissociation are shown in Table 1 (biotitization andesite rock powder and molybdenum ores).
Table 1 Dissociation degree of different fractional molybdenum ore
Size (μm) | Yield(%) | Molybdenum content (%) | Monomer dissociation (%) | |
Heavy liquid method | Microscope area method | |||
+200 | 6.66 | 0.041 | 2.8 | 0 |
-200+100 | 20.49 | 0.053 | 18.1 | 19.8 |
-100+74 | 7.43 | 0.063 | 40.6 | 44.4 |
-74+53 | 8.51 | 0.095 | 59.7 | 65.0 |
-53+43 | 5.38 | 0.102 | 65.2 | 73.9 |
-43+30 | 9.27 | 0.123 | 82.7 | 84.9 |
-30+20 | 9.79 | 0.124 | 90.0 | 90.0 |
-20+15 | 8.61 | 0.124 | 100.0 | 100.0 |
-15+10 | 7.93 | 0.098 | 100.0 | 100.0 |
-10+5 | 15.01 | 0.085 | 100.0 | 100.0 |
-5 | 0.92 | 0.058 | 100.0 | 100.0 |
total | 100.00 | 0.090 | 73.9 | 75.6 |
In the 1970s, the coarse concentrate of the Jinduicheng Molybdenum Plant was only re-milled for a period of time. The selected molybdenum concentrate contained only about 46% molybdenum and the molybdenum recovery rate was close to 80%. In 1979, the extraction research and development company of Amex Company of the United States tested this molybdenum concentrate. The test report shows that for the Jinduicheng molybdenum concentrate containing 46.19% and 46.63% of molybdenum, the dissociation degree of molybdenum ore is only 90%, and the gangue mineral in molybdenum concentrate is about 70%-80% with molybdenum. Mines are connected. In the final tailings containing 0.03% of molybdenum, more than 70% of the molybdenum ore is a continuous body with gangue.
In the 1980 Jinduncheng Second-selection Plant process, it was found that the recovery rate of molybdenum in the selected grades was very low, which was related to the low degree of dissociation of the fractional products. The recovery rate of molybdenum selected particles is shown in Figure 2.
Figure 2 Selected fractions of molybdenum plant
Jinduicheng Molybdenum Industry Co., Northwest Nonferrous Metals Research Institute, Beijing Research Institute of Mining and Metallurgy and Beijing Nonferrous Metals Design and Research Institute found in the study of “Improving the quality of concentrate in Jinduicheng Molybdenum Concentrator†Fineness and increased number of regrind sections can significantly improve the grade and recovery of molybdenum concentrate. When the re-grinding degree of the second stage reaches 96.7%-400 mesh, the selection effect of molybdenum content ≥54% and molybdenum selective recovery rate ≥98% can be obtained (see Fig. 3~Fig. 5). [next]
Figure 3 Fineness and selection indicators
Figure 4 Re-grinding and molybdenum concentrate grade (Jinduicheng ore)
Figure 5 Re-milling number and molybdenum concentrate grade
The skarn molybdenum ore in Yangjiazhangzi has a coarser grain size. In the 150 mesh (100μm) grain size, 80.5% of the molybdenite has reached the monomer dissociation. However, in the granite porphyry molybdenum ore and shale molybdenum ore, the molybdenum ore has a finer grain size, and the same grain size of molybdenite has a lower monomer dissociation degree than Klemax (see Table 2).
Table 2 Comparison of the dissociation degree of Yangjiazhangzi and Klemax's molybdenum ore
mine Monomer solution Degree of deviation (%) Granular grade (μm) | Klekes | Yang Jiazhangzi | |
Granite porphyry molybdenum ore | Angular shale molybdenum ore | ||
50 30 10 | 88.3±1.6 99.4±0.3 | 24.39 51.70 91.54 | 54.39 69.34 93.97 |
According to reports from Zhang Ruifu and Lu Xingchen in 1981, the Yangjiazhangzi Molybdenum Plant has a low degree of dissociation of molybdenum ore, which affects the cyclic loading of selected operations (the fourth selected cyclic load reaches 2100%!), resulting in For a long time, the grade of molybdenum concentrate is not high (about 45% with molybdenum), and the recovery rate of selected molybdenum is low (annual average 96%). After testing, they found that the circulating load has a coarse grain size and a large number of connected organisms (in a finely selected foam product, in the 77-52 μm particle size, the molybdenum ore is up to 80%). They circulate and enrich in the process. As the environment fluctuates, it will be lost from the tailings, resulting in a decrease in the recovery rate of molybdenum; or entering the molybdenum concentrate, resulting in a decline in product quality.
The persimmon garden polymetallic ore, the average grain size of the molybdenum ore is 0.01~0.lmm. When the ore is ground to 89.8%-200 mesh, the dissociation degree of molybdenum ore is only 85%, which makes it difficult to improve the grade of molybdenum concentrate.
In order to obtain high-quality molybdenum concentrate, foreign molybdenum or copper -molybdenum selection plants must add multi-stage regrind operations before or during the molybdenum selection process. The domestic molybdenum plant is also adding re-grinding to increase the dissociation degree of molybdenum ore to improve the quality of molybdenum concentrate.
Jinduicheng Molybdenum Company a processing plant increases the second paragraph of regrinding operations will concentrate mill three times to 80% - 500 mesh, eventually won the molybdenum greater than 53.5%, less than 0.18% copper, lead containing less than 0.05% , high quality molybdenum concentrate containing less than 0.2% calcium oxide.
The Xiaosigou molybdenum-copper mine is operated by two-stage regrind operation. The second section has a fine grinding degree of 86%-360 mesh, and the molybdenum content of molybdenum concentrate increases from 47% to 48% to 53.395%.
Obviously, in order to obtain high-quality molybdenum concentrate, it is absolutely necessary to use a fine grinding process to re-grind the coarse concentrate and improve the monomer dissociation degree of molybdenite.
Due to the different grain size of molybdenite in each mine, the number of regrind segments is different from the fineness of re-grinding. The determining factor is mainly the dissociation degree of molybdenite.
Dry Vacuum Pump,12V Vacuum Pump,High Vacuum Pump,Diaphragm Vacuum Pump
Dongguan Beqile Mechanical&Electrical Equipment CO.,LTD , https://www.betemvacuum.com