Contains small amount of molybdenum in the earth, it is a non-ferrous metal deposits. With the continuous high level of molybdenum product prices in the international market in recent years, the development and utilization of molybdenum resources in various parts of the country have generally warmed up. The use of more efficient sorting process, more effective and rational use of the existing limited molybdenum ore resources has become a hot spot for all molybdenum mine enterprises. However, the domestic old molybdenum mining enterprises currently use uniform old-fashioned flotation equipment and processes, which are less efficient.
In recent years, the research on fine-grain flotation equipment has made great progress, and the swirling-static microbubble flotation column sorting technology has gradually expanded in the field of promotion and application of fine-grain mineral separation. Election in the country's coal plant coal flotation, the flotation column has been applied successfully in the ultra low ash clean coal preparation and coal also made a major breakthrough; in the field of sorting metal ore being widely used It shows a more obvious advantage than the flotation machine in improving the concentrate grade, upgrading the product grade and improving the recovery rate. If it can be widely promoted and applied in the molybdenum ore sorting with limited resources, it is undoubtedly of great significance.
1. Introduction to the cyclone-static microbubble flotation column
(1) The basic principle of the cyclone-static microbubble flotation column
The main structure of the cyclone-static microbubble flotation column includes a column separation section, a cyclone separation section, a bubble generation and a tube flotation section. The basic structure and principle are shown in Figure 1.
Figure 1 Swirl-static microbubble column sorting principle
1-spray pipe; 2-column; 3-bubble generator; 4-valve; 5-pump
The whole flotation column is integrated, the column separation section is located in the upper part of the whole column, and is used for pre-selection of raw materials, and the high-quality concentrate is obtained by virtue of its selective advantage; the cyclone separation section adopts a column-cone connected aqueous medium cyclone structure, And the column separation section is a straight-through connection of the upper and lower structures. From the cyclone separation angle, the column separation section corresponds to the enlarged cyclone overflow tube. At the top of the column separation section, a spray water pipe and a foam concentrate collection tank are arranged; the feed point is located in the upper middle part of the column separation section, and finally the tailings are discharged from the bottom of the cyclone separation section. The bubble generator is directly connected with the tube flotation section and is separately arranged outside the cylinder body; the outflow is connected to the cylinder of the cyclone separation section in a tangential direction, which is equivalent to the tangential feed tube of the cyclone.
The principle advantages of this flotation column are as follows: (1) Combining flotation and re-election methods to form a comprehensive force field advantage and improving sorting efficiency; 2 Forming multiple cycles enhanced sorting with re-election and flotation as the core Chain; 3 supersaturated dissolved gas precipitation and high-efficiency jet foaming method to form microbubbles; 4 filler and sieve plate mixed filling method, constitute a "static" separation environment inside the column.
(II) Current status of industrial application of cyclone-static microbubble flotation column
At present, the cyclone-static microbubble flotation column has been basically applied in coal sorting. The series column sorting equipment has been promoted and applied in nearly 200 coal preparation plants at home and abroad, and on this basis, flotation has been developed. The column is the core of the slime sorting process. It not only realizes the combination of advanced sorting methods, but also reduces the flotation plant by half, the power consumption is significantly reduced, and also makes breakthroughs in the main technical indicators such as clean coal ash, clean coal moisture, and combustible body recovery rate.
Under the promotion of the key scientific and technological projects of the “10th Five-Year Planâ€, the column sorting equipment has also made breakthroughs in the sorting of metal minerals. Nonferrous Metal Company, respectively Shizhuyuan scheelite rougher tailings, DONGCHUAN low grade copper oxide ore high Gongchangling mining company, Inner Mongolia, China Qi copper sulfide, purple hydrometallurgy leaching residue, Jinchuan Ni ore, Fujian Youxi mining companies lead zinc flotation tailings and other various metal ores and non-metallic minerals such as asphalt were the basis for sorting test laboratory flotation column, the mining company in Youxi County, Fujian, Hunan Nonferrous metals Co. Shizhuyuan The company, Yunnan Jinsha Mining Company, Anshan Iron and Steel Group Gongchangling Mining Company and Qihua Mining Group conducted a diversion industrial test. At present, the cyclone-static microbubble flotation column has been selected in Shizhuyuan Nonferrous Metals Co., Ltd., fluorite separation, white tungsten rough selection, copper lead and zinc separation, Inner Mongolia Qihua Mining Company copper and sulfur separation and copper selection, bow length magnetic iron ore mining company Ridge reverse flotation, Yunnan copper Group, floating jade mining companies Dahongshan copper processing factory in the whole process of sorting copper, Zijin copper mine half ASHELE flotation ore sorting operations and other operations Put into industrial operation.
(III) Characteristics of the cyclone-static microbubble flotation column
Compared with other flotation devices, the cyclone-static microbubble flotation column has the following characteristics:
1. High sorting precision and simple process. The fluorite flotation of Shizhuyuan uses 1 rough selection and 3 selection processes to stably obtain high-quality qualified fluorite concentrate; 1 rough selection with flotation machine, 2 sweeps, 9 selections, 2 Compared with the 14-stage operation of the secondary cleaning, the process structure is greatly simplified; the flotation column is sorted and qualified for tailings once, and the grade of 1 rough-concentrated concentrate is more than 90.00%, which is equivalent to the 4-5 segment of the flotation machine. Sorting effect. In addition, the white-tungsten roughing operation of Shizhuyuan uses 1 rough selection, and 1 selection process replaces the crude selection of scheelite from Shizhuyuan Nonferrous Metals Co., Ltd., 1 rough selection, 2 sweeps, 3 selection processes, fine The grade of the mine is 4 to 8 percentage points higher than that of the flotation machine, and the recovery rate is increased by 3 to 5 percentage points.
2. Low power consumption. The results of fluorite sorting and white tungsten roughing in Shizhuyuan show that the use of flotation column can save more than 1/5 of the installed power in the flotation stage.
3. The system is running stably. Easy operation and maintenance equipment, low failure rate, stable during operation; a bubble generator main wearing parts, fluorite flotation column indicates the application sorting and magnetite reverse flotation, the use of high-grade ceramics as alumina crystallites The inner core of the bubble generator, the bubble generator can withstand the abrasion of high-hardness materials. After 1 year of industrial operation, the wear rate of the main over-current components is less than 5%.
4. Automatic control of tailings. The pressure sensor-digital display-electric control valve closed-circuit control can achieve stable regulation of the liquid level. At the same time, a remote control interface is left to achieve centralized control.
2. Resource distribution and ore characteristics of domestic molybdenum ore
At present, there are more than ten kinds of molybdenum minerals, among which the molybdenite is mainly of industrial value.
(1) Distribution of molybdenum deposits
Molybdenum deposits are divided into four categories: porphyry molybdenum deposits, skarn molybdenum deposits, porphyry copper-molybdenum deposits and other molybdenum deposits. China's molybdenum resource deposits are complex in type, but mainly porphyry molybdenum deposits, accounting for 77.3% of the country's total reserves, skarn-type molybdenum deposits accounting for 16.4%, and other types of molybdenum deposits accounting for only 6.3% of total reserves. The molybdenum reserves of a single ore account for 29.7% of the country's total reserves, while the rest are symbiotic deposits such as copper-molybdenum, molybdenum-tungsten and ferromolybdenum. In general, reserves of less than 0.10% grade account for about 65% of the total reserves, while concentrates with a grade of more than 0.30% account for only about 1% of the total reserves.
The domestic molybdenum resources mainly include the extra-large contact metamorphic molybdenum-tungsten deposit in Luanchuan, Henan, the Jinduicheng mega-porphyry molybdenum deposit in Shaanxi, the Yangjiazhangzi large-scale contact metamorphic molybdenum deposit in Liaoning, and the Daheishan porphyry-type molybdenum deposit in Jilin. Molybdenum reserves account for about 70% of the country's total molybdenum reserves.
(2) Characteristics of molybdenum ore
Except for a few places (Yangjiazhangzi, Lanjiagou, etc.), which are single molybdenum ore, most of the domestic molybdenum ore is associated with molybdenum ore, mainly copper-molybdenum ore, tungsten-molybdenum ore, carbonized copper-molybdenum ore and thorium uranium. Molybdenum ore, etc.
The crystal structure of the molybdenum ore is similar to that of graphite , and the molecular force between the layers is non-polar; the end faces exposed by the S-Mo-S interlayer damage are polar bonds. Studies have shown that the floatability of molybdenum ore depends on the surface-to-edge ratio of molybdenum ore with different particle sizes. The larger the proportion of the molecular bond crack surface, ie, the {001} plane, the better the floatability; Or the fine molybdenum ore is reduced in floatability due to a decrease in the proportion of the {001} plane. In addition, the oxidized molybdenum ore decreases contact and the hydrophilic force increases, resulting in a decrease in floatability, and the higher the degree of oxidation, the worse the floatability.
Third, molybdenum ore column sorting practice
The traditional molybdenum ore sorting process uses a flotation machine process, and the process is complicated. The selection often takes 7 to 10 times; while the cyclone-static microbubble flotation column sorting process (referred to as column sorting) is used. The selection takes only 2 to 3 times to achieve the desired concentrate index, and even a satisfactory recovery rate can be achieved without the need of a sweeping step, which greatly simplifies the process and improves the efficiency of molybdenum ore sorting.
At present, the pilot test project of different types of molybdenum ore in two places in Henan has been carried out using the column sorting process, and satisfactory results have been achieved.
(1) Separation test of oxidized ore molybdenum ore
The molybdenum ore of a mine in Henan is a serpentine petrochemical molybdenum ore, a chlorite-rich molybdenum ore, and a strong limonite mineralized ore-poor ore. The useful components are mainly molybdenum ore with high degree of oxidation. The mineral inlays are mainly composed of fine particles. Among the gangue minerals, there are many muddy minerals such as chlorite, serpentine and talc . A large number of primary and secondary slimes affect the recovery of molybdenum, so the molybdenum mine is extremely difficult to select molybdenum ore at home and abroad. [next]
The mine has a 1100t / d processing capacity of the concentrator, divided into two series. A series of 500t / d processing capacity, using 1 rough selection, 3 sweeps, 10 selected processes; two series scale 600t / d, using 1 rough selection, 4 sweeps, 10 fine Selected process.
The main problems in the above process are: 1 the recovery rate of molybdenum metal is low, only 40.00% to 50.00%; 2 the grade of molybdenum concentrate is low, the grade of molybdenum concentrate is only 15.00% to 20.00%, which is the lowest country of molybdenum concentrate. Quality Standard.
In March 2006, the mine cooperated with China University of Mining and Technology to conduct a semi-industrial split test of -20μm fine-grain flotation column by column sorting process, followed by a grain-level semi-industrial split test and a selective split test. Satisfactory test results were obtained; in August 2007, the plant installed 3 industrial flotation columns, and the system was stable after commissioning tests.
The fine mud part is divided into a part of the floating ore mine for hydrocyclone classification, and the -20μm fraction is entered into the column sorting system. After 1 rough selection and 2 times selection, the concentrate product and tailings are obtained; the whole grain fraction The selection is directly from the inlet of the ore flotation into the column sorting system for sorting; the selected part is directly introduced into the flotation machine rough selection concentrate to obtain the final molybdenum concentrate product through three times.
The fine mud and full grain sorting process is shown in Figure 2, and the selected process is shown in Figure 3.
Figure 2 Fine mud / full-grain split flow test procedure
Figure 3 Flotation column selective flow test procedure
The results of semi-industrial split test of fine mud are shown in Table 1. The results of full-scale semi-industrial split test are shown in Table 2, and the results of selected split test are shown in Table 3.
Table 1 Semi-industrial split test results of fine-grained ore %
Shift | Flotation column | Flotation machine | ||||||
Raw ore | Concentrate | Tailings | Recovery rate | Raw ore | Concentrate | Tailings | Recovery rate | |
1 2 3 4 average | 0.169 0.198 0.180 0.210 0.189 | 27.40 29.60 27.45 28.38 29.21 | 0.070 0.082 0.078 0.083 0.078 | 58.73 58.75 56.83 60.65 58.74 | 0.186 0.195 0.217 0.204 0.201 | 22.17 18.58 18.83 17.96 19.39 | 0.09 0.121 0.117 0.102 0.108 | 51.82 37.95 46.37 50.29 46.61 |
It can be seen from Table 1 that for the sorting of fine-grained molybdenum ore, the column sorting has obvious advantages over the flotation machine process, the concentrate grade is increased by 8.82 percentage points, and the recovery rate is increased by 12.13 percentage points. Since most of the high oxidation portion of the ore is present in the fine fraction, it is effective to classify the fine fraction by column sorting.
Table 2 Results of full-grain grade ore stability test %
Shift | Flotation column | Flotation machine | ||||||
Raw ore | Concentrate | Tailings | Recovery rate | Raw ore | Concentrate | Tailings | Recovery rate | |
1 2 3 4 5 average | 0.195 0.184 0.197 0.195 0.191 0.192 | 29.49 26.47 31.89 30.71 30.54 29.82 | 0.102 0.063 0.093 0.097 0.100 0.091 | 47.86 65.92 52.95 50.41 47.80 52.77 | 0.186 0.212 0.194 0.190 0.188 0.194 | 19.67 17.85 18.11 16.38 18.20 18.04 | 0.108 0.111 0.0984 0.108 0.104 0.106 | 42.17 47.94 49.55 43.16 44.94 45.63 |
It can be seen from Table 2 that, in the classification of full-grained molybdenum ore, compared with the fine-grained grade, the column-type sorting concentrate has little change, but the tailings are slightly higher. The main reason is that the ore particle size becomes coarser and the part that is not completely dissociated increases; however, the sorting result of the flotation machine process is better than that under the same conditions. In the case of equivalent feedability, the concentrate grade of the column sorting is improved. 11.78 percentage points, the recovery rate increased by 7.14 percentage points.
Table 3 Selected flotation test results of flotation column
Shift | Rough | Flotation column | Flotation machine | ||||
Concentrate | Fine tail | Recovery rate | Concentrate | Fine tail | Recovery rate | ||
1 2 3 average | 1.73 2.03 1.86 1.87 | 38.74 37.52 39.29 38.52 | 0.235 0.284 0.319 0.279 | 86.94 86.67 83.53 85.70 | 19.89 17.35 19.26 18.50 | 0.798 0.672 0.653 0.708 | 56.25 69.59 67.17 64.61 |
It can be seen from Table 3 that, compared with the results of the 10 selections of the flotation machine, under the same feeding conditions, the two-stage selection of the column sorting is better. The concentrate grade can be increased to 38.52%, which is 20.02% higher than the flotation machine, and the selected recovery rate is increased by 21.09%.
The semi-industrial split test results of the oxidized ore molybdenum ore show that the column sorting has a more efficient sorting efficiency for the high oxidation rate molybdenum ore than the ordinary flotation machine process. Due to the high degree of oxidation of ore, it is difficult to increase the concentrate grade to more than 40.00% under the existing pharmaceutical system conditions, and the recovery rate is difficult to increase to more than 65.00%.
(2) Separation test of gangue type molybdenum ore
The ore molybdenum ore is a quartz vein type molybdenum deposit, mainly composed of granite porphyry and Anshan porphyrite structure. Useful mineral molybdenite minerals are associated mainly magnetite, titanium, iron pyrite, and the like; gangue minerals are quartz, feldspar, mica and chlorite; molybdenite ore dissemination size Fine, closely related to gangue minerals, easy to be wrapped in, difficult to separate; in addition, the ore contains a large amount of pyrite, which is easy to float at the same time as the concentrate, which also increases the difficulty of sorting. Therefore, the ore is difficult to select molybdenite.
The mine has a processing capacity of 2000t/d. The rough selection includes 800t/d of the original factory and 1200t/d of the expansion. 800t, 1200t rough grinding rough series of coarse concentrates, after entering the graded re-grinding and selection system, the coarse concentrate after a period of re-grinding, 9 selections, 1 sweeping, the final molybdenum grade can reach 45.00 About %, the selected recovery rate is about 73%. The main problems of the system are: 1 complicated operation, high number of selections, long process, which is not conducive to system stability; 2 low flotation efficiency (about 45% of molybdenum concentrate grade) and not stable enough. In order to improve the grade of molybdenum concentrate and the recovery rate of the selected links, the mine commissioned the China University of Mining and Technology to carry out the flotation column selection and industrial diversion test at the 2000t/d concentrator, and achieved satisfactory sorting results.
The input of the selected semi-industrial split test is the overflow of the coarse concentrate after classification by the water cyclone, and the final concentrate product is obtained after 3 times of column selection. The semi-industrial split flow of the flotation column selection system is shown in Figure 2. The test results are shown in Table 4.
Table 4 Selected flotation test results of flotation column
Shift | Flotation column | Flotation machine | ||||||
Raw ore | Concentrate | Tailings | Recovery rate | Raw ore | Concentrate | Tailings | Recovery rate | |
1 2 3 4 5 6 average | 8.51 7.24 5.36 5.88 6.43 4.74 6.36 | 52.61 53.06 50.23 51.65 53.87 49.59 51.84 | 0.672 0.613 0.557 0.542 0.571 0.539 0.582 | 93.30 92.60 90.61 91.75 92.10 89.60 91.88 | 9.32 7.15 6.42 5.76 7.47 5.61 6.96 | 48.07 46.38 45.43 45.89 46.96 45.35 46.35 | 1.658 1.620 1.451 1.479 1.502 0.951 1.444 | 85.15 80.14 79.95 76.80 82.53 84.83 81.80 |
It can be seen from Table 4 that the selection of the three types of columns can increase the grade of molybdenum concentrate to 51.84%, which is 5.49 percentage points higher than that of the flotation machine with 9 selections and 1 sweep. According to the national standard of molybdenum ore, the grade of molybdenum concentrate products can be improved; the recovery rate is increased to 91.88%, which is 10.08 percentage points higher than the flotation machine process recovery rate.
The above data shows that the column sorting has obvious advantages over the flotation machine process in the sorting of molybdenum ore.
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