Copper-molybdenum flotation separation technology

At present, the use of flotation to treat copper-molybdenum ore is more common, the process technology is mature, and the indicators are better. In principle, the flotation method of copper-molybdenum ore has three kinds of flotation, preferential flotation, and other flotation. Most of the production is mixed flotation, but sometimes it is preferred to float or float.

Mixed flotation technology of copper and molybdenum

Most copper-molybdenum ore adopts mixed flotation-copper-molybdenum separation process because molybdenite and chalcopyrite are similar in floatability and associated with serious process. The process cost is low and the process is simple.

Mixed flotation

In general, flotation collector xanthates selected (butyl xanthate), an auxiliary collector hydrocarbon oil (kerosene), as blowing agents include pine oil, lime and waterglass adjustment agent . Ye Lijia conducted a test on a low-grade copper-molybdenum mine in Anhui Province. He found that kerosene was used as a collector and BK301C was used as an auxiliary collector for copper-molybdenum mixing. The recovery rate of copper and molybdenum was 93. 01% and 73.2%, the effect is much better than other auxiliary collectors. Mark Ximo Fu is performed mixing inhibitor (sulfur, lime) Experimental Study pyrite inhibiting found that high concentrations of free calcium oxide (700 mg / L) may act to inhibit the action of pyrite, but also inhibits Hui Molybdenum is not conducive to recovery, the recovery rate does not exceed 45%; the combination of sulfur dioxide and lime (250 mg / L) can also inhibit pyrite, and the recovery of molybdenum concentrate can be increased to 57% to 59%.

2. 1. 2 copper and molybdenum separation pretreatment

Under normal circumstances, the copper-molybdenum separation process has two schemes: molybdenum-free float copper and copper-stop float molybdenum. In view of the fact that molybdenum ore is more easily floated, most of them adopt the method of suppressing copper and molybdenum. However, when separating high-copper and low-molybdenum ore, the process of suppressing molybdenum floatation should be considered, because copper inhibition will result in high pharmaceutical costs. In addition, molybdenite has good floatability, and inorganic or organic small molecule inhibitors are not easy to function, which allows the use of some polymer inhibitors such as dextrin, starch, humic acid, tannic acid and the like. At present, only Siver Be and Bingham in the United States use dextrin to carry out the industrial practice of molybdenum-free copper floating. The use of this process should be noted that hydrocarbon oils cannot be used as collectors because of the presence of dextrin in the presence of hydrocarbon oil. The suppression of the mine is invalid. In addition, the infrastructure investment is large, and the process is complex, which is not conducive to promotion and application.

Copper-molybdenum separation mainly includes pre-treatment before separation, inhibition of copper minerals during separation, and re-enrichment after separation of copper and molybdenum. The main methods of preprocessing are as follows:

1) Concentrated mixed concentrate, mainly to remove residual agent and foaming agent in flotation copper-molybdenum mixed concentrate. Liu Zilong and others intensified the application of this pretreatment in the second phase reconstruction of the Wunuge Tushan copper-molybdenum ore dressing plant. The ceramic filter was used as the concentration equipment after the copper-molybdenum mixed flotation, which solved the current situation that the molybdenum ore was difficult to separate and obtained the grade. 57. 75% of molybdenum concentrate. The sulphide concentrate is increased by 0.36%, the recovery rate is increased by 11.14%, and the sodium sulfide consumption is reduced by 32. 17%. .

2) Heating method. Heating the mixed concentrate can decompose the collector on the mineral surface, destroy the hydrophobic membrane, and evaporate the foaming agent in the slurry. Thus, the surface of the copper mineral is oxidized, the floatability is lowered, and the effect is suppressed, and the effect on the molybdenite is minimal, thereby achieving separation. At present, the main heating methods include heaters, roasting, and steam blowing. It is confirmed that about 40% of the world's copper and molybdenum plants are treated by heat treatment, which not only reduces the amount of sodium sulfide, but also significantly improves the beneficiation index.

3) Add the medicine. Primarily oxidizing agents such as peroxide, ozone, chlorine, potassium permanganate, oxygen, etc., in order to oxidize the surface thereof and the hydrophilic copper, collector adhered oxidized and decomposed. When the pH is 10 to 11, O2 in the slurry oxidizes the chalcopyrite to S2O32- and inhibits it. Natarajan et al. used electrochemical tests to verify that ozone effectively oxidizes and decomposes chalcopyrite surface collectors and is more effective than oxygen. Therefore, by controlling the slurry conditions such as oxygen supply, pH adjustment, etc., it can inhibit the realization of copper-suppressing molybdenum in chalcopyrite, but it should be noted that the amount of oxidizing agent should not be too much. If it is excessive, it will affect the next copper suppression. The molybdenum unit has a strong reducing effect of sodium sulfide.

2. 1. 3 Copper-molybdenum separation inhibition

An important aspect of the copper-molybdenum separation process after pretreatment is the selection of flotation inhibitors. Commonly used inhibitors can be divided into inorganic and organic substances, inorganic substances are mainly Knox, cyanide, sodium sulfide, etc., organic substances are mainly thioglycolate, etc., either alone or in combination.

1) Cyanide. A complex comprising cyanide such as zinc cyanide or sodium ferricyanide. Mainly for copper, iron sulfide ore suppressed, and its object is to destroy xanthate, cyanide stable complex formation, is very effective, highly efficient small amount, in Jinduicheng processing plant production applications, the molybdenum fine The 5% molybdenum concentrate is obtained by adding sodium cyanide from 0. 05 to 0. 06 kg / t. However, it is highly toxic, especially in the case of mines containing gold and silver . The application of this method in the plant is gradually reduced.

2) Knox class. Including arsenic Knox Pharmacy, Phonon Knox Pharmacy, mainly effective inhibitors of copper, lead and iron sulphide, low dosage, fast reaction, long acting time, the addition of Phosphonium to the Cherita copper mine in the United States after steaming The ketone agent is used to suppress copper molybdenum, and the final molybdenum concentrate contains 46% to 50% molybdenum, 3% copper, and the molybdenum recovery rate is 75% to 78%. However, Knox's presence of phosphorus and arsenic can contaminate concentrates, which are difficult to control and pollute the environment.

3) Sodium sulfide. Mainly sodium hydrosulfide, sodium sulfide, ammonium sulfide, etc., the research confirmed that the main inhibitory effect is the SH- formed by the hydrolysis of sulfide. The most used in actual production are sodium sulfide and sodium hydrosulfide. For example, Dexing Copper Mine uses Na2S for copper-suppressing molybdenum. The beneficiation index is good, but sodium sulfide is easily oxidized and ineffective, up to 80-100. Kg / t, the proportion of pharmaceutical fees is quite high, accounting for 85% of the cost of molybdenum. To this end, the United States Pima plant has studied the use of 85% Na2S and 15% (NH4) 2S ratio, reducing the amount of Na2S by 75%, increasing the 23.3% molybdenum grade in the coarse concentrate, there are also transportation problems, (NH4) 2S The problem of expensive price. The Mikhanopur Institute of Russia has developed an oxygen absorber, the principle of which is to reduce the oxidation of sodium sulfide by absorbing oxygen in the slurry. When the pressure is 0.7 MPa and 95 °C, the amount of dissolved oxygen can be absorbed by 41%. The amount of sodium sulphide is reduced by 2 / 3.

Another method to significantly reduce the amount of Na2S is nitrogen charging. The first nitrogen-purifying process was the Peruvian Kwahonet plant, which uses gaseous nitrogen and the inhibitor NaHS is reduced by 70%, but there is a lack of nitrogen removal devices and preventive measures. The Russian Research Institute designed a closed flotation machine with a deaerator and selected the Qazaran plant for testing. The initial sodium sulfide consumption was reduced by 30%. Domestically, the Beijing Nonferrous Metallurgy Design and Research Institute also selected the Dexing Copper Mine to conduct a nitrogen-filled industrial test, which reduced the amount of sodium sulfide by 60.55%. It is worth noting that sodium sulfide and sodium cyanide can inhibit chalcopyrite well, but the inhibition effect on a large amount of chalcopyrite and secondary chalcopyrite is quite poor.

4) Mercaptoacetate. In particular, thioglycolic acid has good inhibition effect, low dosage, low pollution and high selectivity. Wan Shenghui and other thioglycolic acid were synthesized by sodium sulfide method, and industrial experiments were carried out in Dexing Copper Mine. Good inhibitor effect was obtained. The obtained molybdenum concentrate grade was 51.53%, and the molybdenum concentrate recovery rate was 79. 89%。 The copper content is only 0.32%.

5) New inhibitors. Jiang Yuren et al. synthesized a new type of inhibitor DPS. The test showed that it can significantly inhibit chalcopyrite and galena, but has little effect on molybdenite. The dosage is 1/5 of sodium thioglycolate and 1/10 of sodium sulfide. The stability is good, the synthetic route is simple, and the raw material price is low. Yuan Zengwei studied the new inhibitor CM1. Compared with thioglycolic acid, the inhibitory effect of CM1 was more obvious, the dosage was less (20 g / L reduction), the action time was fast, and the lead ore was also inhibited.

2. 1. 4 Copper and molybdenum separation selection

After the separation of copper and molybdenum, the next step of molybdenum selection and copper selection is carried out. The molybdenum is generally selected six times to meet the smelting requirements. Sometimes some molybdenum in the flotation concentrate will not be completely dissociated, and the regrind process is inevitable. Zhang Hengwang will improve the process of the Xiaosigou copper-molybdenum ore and increase the regrind process before molybdenum selection. The final concentrate grade of molybdenum reaches 46.49. %, the recovery rate was 92.26%, which was 0.5% and 3.97% higher than that without regrind.

Copper selection is relatively simple, generally a selection can be, but the technology of asynchronous mixed flotation is worth mentioning, that is, flotation of float float copper, and enhanced flotation of difficult copper (addition of xanthate) Mix two-step copper concentrate and re-select it. This technology has been tested in the Dexing Copper Mine and the recovery rate of molybdenum and copper has increased. Zhu Siling and others studied the rapid flotation, that is, the use of the strong selective collector AP flotation monomer copper coarse particles and the rich copper body, and then the copper and molybdenum mixing and separation, copper concentrate grade increased by 0.89 %, the recovery rate increased by 0.19%, this technology has been applied in the Dashan plant.

2. 1. 5 Copper and molybdenum separation new technology and new equipment

1) Application of flotation column

One of the advantages of the flotation column is that it has a good recovery effect on the difficult mineralized fine particles and fine mud content. The characteristics of the copper-molybdenum ore are fine grain size, low ore grade, serious associated, and need fine grinding grain size. The smashing phenomenon is serious, and sorting becomes difficult. Therefore, a flotation column can be used instead of a part of the flotation machine to enhance the sorting effect. At present, there are many flotation columns used, such as cyclone-static microbubble flotation column, Jameson flotation column, SFC type filling type static flotation column, etc. Ma Zilong et al. used a rotation in the reconstruction of a copper-molybdenum plant in Xinjiang. The flow-static microbubble flotation column is used as the main equipment for copper-molybdenum mixed flotation, copper-molybdenum separation and molybdenum separation. The copper-molybdenum separation sweeping and copper-molybdenum mixed flotation are carried out by flotation machine to form the combined column flotation system. The recovery index is 50.59% of the molybdenum concentrate grade, 55.96% of the molybdenum recovery, 21.39% of the copper concentrate grade, and the copper recovery rate of 91.57%.

2) Application of potential adjustment technology

Flotation electrochemistry is also quite a driving force in the separation of copper and molybdenum. The sequential flotation of different sulfide ore is achieved by controlling the slurry potential. Chander et al. tested the use of externally controlled potential method for electrochemical flotation separation of molybdenite and chalcopyrite. Krishnaswamy et al. concluded that molybdenum ore is naturally floatable due to its poor electron-conducting ability, that is, the change in slurry potential. The influence of the chalcopyrite flotation is oxidative pulp. Therefore, the chalcopyrite can be suppressed under the reducing atmosphere by controlling the pH and potential of the slurry, and the molybdenite can still be floated. To achieve separation. This also explains the root cause of the addition of sodium sulfide to create a reducing environment for flotation and the high and unstable amount of sodium sulfide. Sun Chuanqi et al. conducted a practical study on electrochemical controlled flotation of 0.5.9% copper ore in the ore copper grade. The flotation of molybdenum, copper and iron sulfide minerals was controlled by controlling flotation pH and Ep. 9%。 The copper content of the mixed concentrate is 25.88%, the recovery rate is 85.61%, which is 5.90% and 0.67% higher than the conventional flotation (without electrochemical control). It can be seen that the potential adjustment technique is worthy of study and applied in practice.

2. 2 Copper-molybdenum priority flotation technology

For low-grade molybdenum-copper ore, while ensuring the grade and recovery rate of molybdenum concentrate, it is also necessary to consider the comprehensive recovery of copper, and it is sometimes more appropriate to use preferential flotation.

Dai Xinyu et al. conducted a study on a copper-molybdenum deposit in Tibet. The copper-molybdenum ore has secondary secondary copper and high oxidation rate. The size of the chalcopyrite inlay is fine, and the phenomenon is encased by gangue. The molybdenite is embedded in the vein. Stone cracks and intergranular, the process is preferentially floating molybdenum, re-grinding separation of copper and molybdenum, floating molybdenum tailings recovery copper, molybdenum mineral collector is kerosene + diesel, copper and molybdenum separation inhibitor DY08, copper collector OSN- The result of the selection is 55.66% of the molybdenum grade in the molybdenum concentrate, 0. 071% of the copper, the recovery rate is 88.58%, the copper grade in the copper concentrate is 21.84%, and the recovery rate is 75.93%. Save 10% less than hybrid flotation.

2. 3 Copper and molybdenum flotation technology

In general, both preferential flotation and mixed flotation require high alkalinity (lime) to separate copper and molybdenum from sulfur. Lime has an inhibitory effect on molybdenum and is not conducive to the recovery of molybdenum. Such flotation can avoid such problems. Selective collectors are used, and no separation or use of lime is used to separate copper molybdenum from sulfur, which is beneficial to the next copper-molybdenum separation and molybdenum selection. Better indicators. Hu Zhenfeng used an equal flotation process in the research of a copper-molybdenum ore process. The mine has a low molybdenum grade and slightly more pyrite. The use of weak collectors for pyrite is first carried out by floatation of molybdenum and copper, copper and molybdenum separation; copper-sulfur mixed floatation, enhanced copper-sulfur separation process, in which kerosene and BK340 are floatable The collector, BK901B + butyl yellow drug as a mixed float copper-sulfur collector, the result is: molybdenum concentrate grade 48.85%, recovery rate 68. 96%, total copper concentrate grade 22. 85%, recovery rate 87%。 Recovery rate of 61.07%. The preferential flotation and mixed flotation beneficiation indicators are not much different, but preferential flotation can reduce the amount of inhibitors in copper and molybdenum separation, reduce slurry viscosity, and reduce costs.

3 Copper and molybdenum alloying and metallurgy technology

For most porphyry copper-molybdenum deposits with molybdenum and copper symbiosis, flotation treatment can be used. However, in the treatment of certain refractory copper-molybdenum ore, it is possible to use a combination of metallurgy and metallurgy. For example, Utah Bingham Canyon copper molybdenum, molybdenum copper porphyry belongs, the main mineral molybdenite, chalcopyrite, talc, sericite large content, of the clay mineral and easy. 4%。 The traditional process is a mixed flotation, copper-free floating molybdenum, multiple molybdenum selection, reverse flotation talc, obtained molybdenum containing 52.3% concentrate, re-oxidation roasting, the recovery rate is only 49.4%. The flotation hydrometallurgical combined technology was proposed. The difference was that the copper-molybdenum mixed concentrate was coarsely selected, and the crude molybdenum concentrate (molybdenum 40.5%, copper 3.6%) was treated by oxygen pressure oxidation. Specifically, the crude molybdenum concentrate is added with water to prepare a slurry having a solid content of 500 g / L, and placed in an autoclave, and then 20 g / L of acid and 15 g / L of copper chloride are added, and the temperature in the autoclave is set to 150 ° C. The leaching rate is 96.2%. The filtrate is high-grade molybdenum concentrate (containing only 0.1% copper), the filtrate contains 31.34 g / L of copper, and the copper leaching rate is 96.2%. The process has low leaching pressure and low temperature, and only consumes a small amount of CuCl2, which can be used for the treatment of mixed concentrates, has high indexes, and also reduces the consumption of inhibitors in traditional copper-molybdenum separation and reduces costs.

4 Conclusion

Mixed flotation is applied to the separation of most copper-molybdenum ore. Sometimes it is worthwhile to consider flotation and flotation. The key point is that the grades of copper and molybdenum in the ore and the size of the inlay will affect the dosage and grinding. The other links, that is, the economic cost of mineral processing and the quality of mineral processing indicators.

Effective pretreatment and selection of inhibitors are the key links of copper-molybdenum mixing and re-separation. Concentration, heating and oxidation can effectively destroy and remove the agent, but it should not cause "secondary pollution" to affect the separation of copper and molybdenum. The inhibitory effects of ketones, cyanide, and sodium sulfide are good, but there are deficiencies in "toxicity" or excessive use. Thioglycolate is more promising, and the dosage is less efficient. The development of new pharmaceuticals and combination medications is still a worthwhile effort.

The new technology of copper-molybdenum separation needs further exploration and research, such as potential control technology, pulsation high-gradient magnetic separation, etc., especially potential control is effective in reducing the consumption of inhibitors and obtaining the best molybdenum-copper flotation conditions. The different methods of achieving separation of molybdenum ore magnets also need to be explored and improved.

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