Molybdenum concentrate containing greater than 57% molybdenum (MoS 2 containing greater than 95%) is mainly used in the chemical industry, conventional hydrometallurgical purification and abroad, not only costly, but also pollute the environment. Jinduicheng Molybdenum Group Co., Ltd. (hereinafter referred to as gold Molybdenum Group) thirty acres of molybdenum concentrate grade beneficiation plant has reached more than 52% in the leading domestic level, but the quality on the international market 54% of molybdenum concentrates In comparison, there is still a certain gap. In addition, the company's processing of molybdenum disulfide powder requires a molybdenum concentrate with a grade of 56%, and the original flotation process cannot meet the production requirements, resulting in limited production of molybdenum disulfide. In order to improve the technical level of molybdenum ore and the competitiveness of molybdenum products in China, the research and industrial production of molybdenum concentrate with a molybdenum grade of 57% by flotation method was carried out.
I. Process mineralogy research
(1) Ore properties
Molybdenum Ore JINDUICHENG type steel into flower porphyry, shale angle of the type of the type biotite, chlorite silicified type and type of metal ore minerals are mainly molybdenite, pyrite, yellow copper ore, magnetite, non-metallic minerals feldspar, quartz, mica and the like. The multi-element analysis results (%) of the ore were: Mo 0.135, Cu 0.038, Pb 0.004, S 3.06, TFe 6.56, SiO 2 58.53, CaO 2.89, MoO 3 0.005, P 2 O 5 0.25, TiO 2 0.87, CaF 2 1.16, Al 2 O 3 11.98.
Molybdenum ore is mainly distributed in various veins in the form of scales, flakes and slats. It is closely related to quartz, feldspar, muscovite, pyrite and chalcopyrite, and is mainly distributed at -0.592mm. It is a fine-grained inlay. Its inlaid grain size is the coarsest in granite porphyry, thicker in horn shale, sericitization and chlorite petrified andesite, and the finest in the biotite-forming Anshan shale. In order to obtain a high-grade molybdenum concentrate, the molybdenum ore must be sufficiently monomerized to be dissociated without over-grinding.
(II) Analysis of physical and chemical properties of the original production of molybdenum concentrate
1. Multi-element analysis of molybdenum concentrate
The results of multi-element analysis of molybdenum concentrate are shown in Table 1.
Table 1 Multi-element analysis results of original production molybdenum concentrate
element | Mo | SiO 2 | Cu | Pb | CaO | P | As | TFe |
Quality score | 51.89 | 5.04 | 0.058 | 0.030 | 0.500 | 0.010 | <0.01 | 1.23 |
It can be seen from Table 1 that the main impurity chemical constituents in the original production molybdenum concentrate are SiO 2 and iron. SiO 2 is carried by quartz and silicate, which is mainly carried by pyrite and chalcopyrite. In addition, the CaO content is also relatively high. In order to effectively separate these impurity minerals from molybdenite, an effective regulator must be added. Therefore, the use of effective inhibitors to achieve effective separation of molybdenum and impurities is one of the technical difficulties of this research.
2. The particle size composition and monomer dissociation of the original molybdenum concentrate
The particle size composition and monomer dissociation of molybdenum concentrate are shown in Table 2.
Table 2 Particle size composition and monomer dissociation of molybdenum concentrate
Size/μm | Yield | grade | Metal distribution rate | Remarks |
+74 -74+48 -48+40 -40+38 -38 total | 2.38 16.54 4.46 5.94 70.68 100.0 | 51.84 50.67 50.30 49.27 52.05 51.89 | 2.39 16.25 4.35 5.68 71.33 100.0 | The monomer dissociation degree is 96.30% |
It can be seen from Table 2 that the fineness of the original production molybdenum concentrate is -38 μm, accounting for 70.68%, and the particle size is relatively fine. However, the grade of molybdenum concentrate is relatively low, and the grade of -38μm is only 52.05%, which indicates that the surface of the ore is contaminated by residual chemicals and slime. There is also mechanical inclusion during the selection process, which affects the grade of molybdenum concentrate. main reason. Therefore, using a new regrind or scrub process, grinding and stripping off the oil and contaminants adsorbed on the surface of the ore particles, and opening the foam agglomeration is the second technical difficulty in improving the grade of molybdenum concentrate.
In addition, although the degree of dissociation of the original molybdenum concentrate has reached 96.30%, the molybdenum grade of +38μ is significantly lower than the -38μm grade. It is necessary to study the regrind process to make +38μm. The granules of the commensurate further dissociate.
Second, the original selection process improvement research
Through in-depth systematic experimental research, a series of transformations were carried out on the original selection process of the arable land concentrating plant, mainly including: (1) adding another fine selection to the coarse concentrate, removing a large amount of fine-grained slime, and increasing the coarseness. Concentrate grade to 12% to 13%; (2) The first stage of regrind position is determined after the primary selection of low grade coarse concentrate, grinding fineness is -38μm80%; (3) second stage regrind The first section was re-grinded at intervals of 3 flotation operations, and the grinding fineness was -38 μm 85%. Through the above improvements, the useful minerals are fully dissociated, the process structure is more reasonable, and the process conditions are more optimized.
Third, deep selection process research
(1) Determination of the test plan
After the improvement of the original selection process, a molybdenum concentrate with a grade of 57% can be produced, but the yield is only 5% to 6%, the recovery rate is low, and the metal loss is serious. In order to ensure the recovery rate, the molybdenum concentrate produced on site was subjected to a deep selection process research. It is planned to re-flot the molybdenum concentrate and sort out two products, one is a molybdenum concentrate with a grade of 57%, and the other is a molybdenum concentrate with a grade of 57%. One is a common molybdenum concentrate. According to the particle size composition of the molybdenum concentrate and the state of occurrence of the main impurities, the test scheme is determined as follows: (1) using the re-grinding and scrubbing process to further dissociate the fine-grained continuum, scrub the surface of the ore, and reduce mechanical inclusions; ) was added sodium silicate and silicate mineral quartz inhibition; and (3) adjusting the pH of the floating mineral with sodium hydroxide, pyrite suppressed; (4) adding TGA, P-Nokes inhibition chalcopyrite, galena, etc. Sulfurized minerals.
(II) Main process conditions test
1, the dosage test
According to the results of preliminary experiments, it was determined that the amount of TGA and P-Nokes was 700 kg/t (calculated as molybdenum concentrate). Through experimental research, it was determined that the amount of water glass and sodium hydroxide was 10 kg/t.
2, regrind test
The results show that the molybdenum concentrate can be directly selected without re-grinding. Due to the serious pollution of the surface of the ore by the oil and the low particle size of the molybdenite monomer, the grade of molybdenum concentrate is difficult to be greatly improved. . When the regrind fineness reaches -38μm88%, the concentrate grade is obviously improved, but the fineness is increased, which will lead to the decrease of concentrate yield, which is related to the fine muddy muddy and the poor selection effect. Considering comprehensively, the regrind fineness of molybdenum concentrate is determined to be about -38 μm and about 90%.
3, scrub test
According to the data, the scrubbing is mainly to remove the pollutants on the surface of the mineral, open the fine particles and a certain amount of grinding and stripping, thereby restoring the original physical and chemical properties of the mineral surface and improving the sorting efficiency. The test results show that the flotation after scrubbing can increase the grade of molybdenum concentrate by 1% to 2%. Therefore, scrubbing technology can be used in the selection of molybdenum. The scrubbing position and the regrind interval are more reasonable 2 to 3 times.
4, flotation concentration test
Tests have shown that flotation concentration has a significant effect on concentrate grade. The smaller the flotation concentration, the higher the concentrate grade, but the lower the yield, and vice versa. It indicates that the higher the concentration, the more serious the impurities are mixed with the foam. Comprehensive analysis to determine the appropriate flotation concentration is about 12%.
(III) Process structure test
The main process plan has three: one-stage re-grinding; two-stage re-grinding; one-stage re-grinding and one-stage scrubbing. The test results are as follows: the yield of a regrind concentrate is relatively large, but the grade is low, it is difficult to ensure the stable production of high quality molybdenum concentrate, so it is not suitable; the grade of re-grinding concentrate is high, but the yield is small; The result of re-grinding and a scrubbing process is the best, not only the high grade of concentrate, but also the yield of concentrate. Therefore, it is determined that a process of re-grinding, one-stage scrubbing, one roughing, and five selections is adopted.
(4) Closed circuit test
A closed circuit test was conducted based on the study to determine the optimum process conditions. The test procedure is a re-grinding, a scrub, a rough selection, and five selections. The test results show that the high-quality molybdenum concentrate grade can reach 58.14%, the yield is 51.60%, and the tailings grade is 45.26%, which can be used as ordinary molybdenum concentrate.
4. Research on structure and parameters of selected flotation machine
The economic indicators of flotation technology are closely related to the performance of the flotation machine used. In order to find a flotation machine suitable for molybdenum selection, the experimental research on the structure, parameters and models of the selected flotation machine was systematically carried out. The research results show that the jet flotation machine can reduce the mechanical inclusion of fine-grained gangue and improve the concentrate grade, but the operation condition is greatly affected by the fluctuation of the ore supply. It is difficult to control in the field operation and the index is unstable; JF-1.5 type The flotation machine can also improve the concentrate grade to a certain extent, but during the operation, the foam spray device is difficult to operate normally, and the foam is not feasible due to the viscosity of the selected foam, and the foam is not feasible; After the improvement of the flotation machine, its performance is superior, the selection of the selected grade is relatively large, the operation is convenient, the operation is stable, but the power consumption and one-time investment are large; the WCF flotation column improves the grade and the operation is more obvious than the jet. The flotation machine is stable, but the operation is inconvenient and the index fluctuates greatly. Comprehensive analysis and comparison, BF flotation machine is the best model.
Five, process design
(1) Design ideas
1. Reform the original selection process and apply the deep selection process. The concentrate grade of selected operations is about 54%, and the deep selection operation ensures that the quality of high-quality molybdenum concentrate is over 57%.
2. The process is flexible. Normally only open selected work, when you need more than 57% of the product, start the deep selection operation.
3. In the process, measures are taken to increase the concentrate concentrate and remove the drug, adjust the regrind position, add water glass and sodium hydroxide, and adjust the working concentration and flotation time.
4. The flotation machine adopts BF type self-priming flotation machine.
(2) Design process
According to the experimental research, combined with the original selection process status of the arable land concentrating plant, the design process flow is as follows: the coarse concentrate enters the thickener for concentration and drug removal, the bottom of the thick machine flows through the I section for re-grinding, three times for selection, and the second stage for re-grinding. Six selections were made to obtain a molybdenum concentrate with a grade of 54%. In order to obtain high-grade low-containing molybdenum concentrate, the selected foam is subjected to strong flotation, concentrated de-drug, one-stage re-grinding, one rough selection, and five times of selection to obtain molybdenum ≥57%, SiO 2 < 2.5% high quality molybdenum concentrate.
The technical specifications of the design process are shown in Table 3.
Table 3 Design indicators
operation | product | Yield | grade | Recovery rate |
Featured | Rough selection Concentrate Fine tailings Raw ore | 2.314 0.208 2.106 100.0 | 5.00 54.00 0.154 0.130 | 89.00 86.50 2.50 100.0 |
Deep selection | High quality molybdenum concentrate Low quality molybdenum concentrate Raw ore | 50.00 50.00 100.0 | 57.00 49.00 53.00 | 53.77 46.23 100.0 |
Sixth, industrial production practice
(1) Comparison of selected segments
In October 1999, 57% of molybdenum concentrate technology was applied to the acreage plant. More than five years of production practice showed that the grade of coarse concentrate reached 6.40%, which was 2.41% higher than that before the transformation. The recovery rate of rough selection reached 88.94%, which increased by 0.26%. The grade of molybdenum concentrate in the selected section reached 53.39%, which improved. 1.45%; the selected recovery rate reached 98.18%, an increase of 2.60%. The molybdenum theoretical recovery rate reached 87.31%, an increase of 2.55%. The comparison of indicators before and after the transformation is shown in Table 4.
Table 4 Comparison of production indicators of selected systems before and after renovation
stage | Raw ore grade | Coarse concentrate grade | Concentrate grade | Rough selection Recovery rate | Featured Recovery rate | theory Recovery rate | year |
Transformation of the former | 0.135 0.143 0.151 | 3.99 4.20 6.25 | 51.94 53.20 53.36 | 88.68 88.82 88.79 | 95.58 97.63 98.43 | 84.76 86.71 87.40 | 1999 2000 2001 |
After transformation | 0.145 0.142 0.138 | 6.64 7.23 7.65 | 53.54 53.31 53.53 | 88.83 88.98 89.26 | 98.38 98.29 98.14 | 87.39 87.46 87.60 | 2002 2003 2004 |
Average after transformation | 0.143 | 6.40 | 53.39 | 88.94 | 98.18 | 87.31 | |
Increase | +2.41 | +1.45 | +0.26 | +2.60 | +2.55 |
(2) Deep selection process application effect
After many process investigations, the research on deep selection process is reasonable and the technical indicators are stable. Under the premise of not affecting the recovery rate, the high-quality molybdenum concentrate grade is 57.52%, the SiO 2 content is less than 2.0%, the yield is 51.14%, and the recovery rate is 53.82%, which meets and exceeds the design index (see Table 5). The quality index of 57% molybdenum concentrate is shown in Table 6.
Table 5 Depth selection process production indicators
product | Yield | grade | Recovery rate | |||
design | actual | design | actual | design | actual | |
High grade molybdenum concentrate Low grade molybdenum concentrate Selected as molybdenum concentrate | 50.00 50.00 100.0 | 51.14 48.86 100.00 | 57.00 49.00 53.00 | 57.52 48.29 53.18 | 53.77 46.23 100.0 | 53.82 46.18 100.0 |
Table 6 57% molybdenum concentrate quality indicators
element | Mo | SiO 2 | CaO | Cu | Pb | TFe |
Quality score | 57.45 | 1.43 | 0.24 | 0.039 | 0.035 | 0.43 |
The successful application of the deep selection process has created a precedent for the production of 57% molybdenum concentrate by flotation, which indicates that the gold and molybdenum group's mineral processing technology and product quality have reached the international advanced level. According to the market demand, Jinmo Group can rationally adjust the proportion of products, organize industrial production flexibly, and provide high-quality raw materials for the subsequent processing industry, thereby improving the technical level of molybdenum industrial chain and the technical content of molybdenum products, and maintaining the sustainable and healthy development of the company.
Seven, technical and economic analysis
(1) Analysis of technical level
Molybdenum beneficiation technology is the most popular in the United States and Canada. Its characteristics are large scale, advanced process facilities, high level of automatic control, high recovery rate of mineral processing and high product quality. See Table 7 for comparison of mineral processing technology and main production indicators of similar mines at home and abroad.
It can be seen from Table 7 that the grade of foreign molybdenum ore is generally high, and the molybdenum mineral has a coarse grain size and is easy to dissociate from the monomer, which is conducive to sorting and obtaining good technical indicators. Molybdenum selection process, most of the foreign countries are more re-grinding segments, less selected times. In contrast, foreign countries mostly have more refining segments and fewer selections. In contrast, the gold and molybdenum group's selection process after the transformation of the acreage plant has only two stages of re-grinding. In the case of low ore grade, the grade of molybdenum concentrate is over 53%, and the selected recovery rate is 98.18. %, reaching the international advanced level. 57% molybdenum concentrate is commonly used for hydrometallurgical purification at home and abroad, and 57% of molybdenum concentrate is industrially produced by flotation. There is no successful precedent at home and abroad. Therefore, the research is the first of its kind outside the country, and its technical level has reached the international advanced level.
Table 7 Comparison of production indicators of major molybdenum concentrators at home and abroad
country | mine | Raw ore | Molybdenum concentrate | Molybdenum selection process characteristics | ||
grade | Grinding fineness -74μm | grade | Featured Recovery rate | |||
nice country | Pod Max | 0.170 | 40～45 | 54 | 98 | Concentrated concentrate of crude concentrate, three sections of re-grinding (gravel), one scrub, five times of selection, one or two selections each have a sweep of coarse concentrate concentrate and drug removal, three sections of re-grinding (gravel), four The second selection, one, two, four selections each have a sweeping three-stage re-grinding, five selections of a re-grinding, eight selections, one fine selection, two sweeps. Deep selection system: one regrind, one rough selection, five selections |
nice country | Henderson | 0.300 | 43 | 54 | 97.5 | |
Canada | Ndak | 0.090 | 40~42 | 54 | 98 | |
in country JDC | Baihualing | 0.132 | 55~60 | 52 | 98.08 | |
Acre | 0.132 | 55~60 | 57 | 98.18 | ||
(II) Analysis of economic benefits
After research and application, the selected system has achieved significant economic benefits due to the improvement of molybdenum concentrate quality and recovery rate; the deep selection process uses flotation to produce 57% molybdenum concentrate, and the production cost is lower than that of hydrometallurgy. (Deep selection production cost is 700 yuan / t concentrate, acid leaching process production cost is 1000 yuan / t concentrate), product quality meets molybdenum disulfide production demand, for the molybdenum disulfide acid leaching process to reduce the amount of hydrofluoric acid The foundation. According to the calculation, the production cost of molybdenum disulfide is reduced by nearly 10,000 yuan/t due to the improvement of the quality of molybdenum concentrate. Since the application of the results, the economic benefits calculated in each year are shown in Table 8.
Table 8 Economic Benefit Calculation Results
year | New production value | New profit | Molybdenum disulfide cost savings | New tax | New sum of profits and taxes |
2000 2001 year 2002 Year 2003 year 2004 Total The annual average | 982 1241 1745 2288 6120 12376 2475 | 634 857 1129 1480 3957 8057 1611 | 162 478 560 562 945 2707 542 | 234 296 416 545 1459 2950 590 | 1030 1631 2105 2587 6361 13714 2743 |
(3) Analysis of social benefits
The industrial production of 57% molybdenum concentrate has improved the level of molybdenum beneficiation technology in China, increased the competitiveness of China's molybdenum products and product competitiveness, and enhanced the international reputation of China's molybdenum products. Secondly, it is the same mine technology research and technology. Providing and providing for the renovation; at the same time, providing high-quality raw materials for the production of two broken molybdenum powder and roasting "60" molybdenum oxide by the Golden Molybdenum Group, thereby producing higher value added molybdenum chemical and molybdenum deep processing products, and leading the domestic and international molybdenum group The molybdenum market and catching up with the international molybdenum level have important practical significance.
Eight, conclusion
(1) Through a series of studies, the original selection process of the arable land concentrating plant was successfully transformed, and significant economic benefits were achieved.
(2) After the deep flotation process is directly set to the selected one, the conventional fertilizer and single flotation method are used to increase the molybdenum concentrate from 52% to 57% without affecting the recovery rate, and to produce molybdenum disulfide powder. Providing high-quality raw materials, technical level and product quality have reached the international advanced level, and played a positive role in promoting the progress of China's molybdenum beneficiation technology.
(3) Scrubbing can clean the pollutants on the mineral surface, open the foam agglomeration, restore the fresh surface of the mineral, and improve the sorting effect.
(4) Using TGA, P-Nokes, water glass and other combined inhibitors, it can solve the separation problem of molybdenum and copper, lead, silicon, etc., and reduce the impurity content in molybdenum concentrate.
(5) BF high-efficiency flotation machine with good flotation dynamics, capable of forming a stable and suitable thickness foam layer, strengthening secondary enrichment, providing high-quality molybdenum concentrate and improving selective recovery rate An important guarantee.
(6) Through technological innovation, the production of molybdenum concentrate containing more than 57% molybdenum by flotation method is the first in China and abroad and has reached the international advanced level.
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