In our country, molybdenum resources are extremely abundant, accounting for a significant share of the world’s total. 37% The main mining areas are concentrated in Henan, Shaanxi, Liaoning, Hebei, and other regions, with the vast majority of copper-molybdenum resources originating from porphyry-type copper-molybdenum deposits. Currently, as economic development continues to drive increasing demand for copper and molybdenum, the available resources face several challenges: there are many low-grade ores but few high-grade ones; severe co-occurrence of associated minerals; abundant presence of other valuable components; fine grain sizes of mineral particles; and similar floatability between molybdenite and copper sulfide minerals—all of which make copper-molybdenum separation particularly difficult. Therefore, research into and application of copper-molybdenum separation technologies have become especially important.

　　1. Copper-molybdenum flotation separation technology

　　Currently, flotation is widely used for processing copper-molybdenum ores. The associated process technology is well-established and delivers excellent performance indicators. In principle, there are three main flotation methods for copper-molybdenum ores: mixed flotation, preferential flotation, and isoflotation. In industrial practice, mixed flotation is the most commonly chosen method; however, preferential flotation or isoflotation are also occasionally employed.

　　2. Copper-molybdenum mixed flotation technology

　　Most copper-molybdenum ores are processed using mixed flotation. - The copper-molybdenum separation process is employed because molybdenite and chalcopyrite have similar floatability and occur in close association. This process has low costs and a relatively simple flow sheet.

　　3. Mixed flotation stage

　　In general, xanthate-based collectors are typically used for mixed flotation. ( Butyl xanthate ) Auxiliary collector—hydrocarbon oil ( Kerosene ) Pine oil is used as a frother, while lime and water glass serve as modifiers. Ye Lijia conducted experimental studies on a low-grade copper-molybdenum ore in Anhui Province and found that kerosene acts as a collector. BK301C Used as an auxiliary collector for the mixed flotation of copper and molybdenum, 59 g/t The dosage is sufficient to achieve copper and molybdenum recovery rates of, respectively, 93.01% and 73.2% Its effect is much better than that of other auxiliary collectors.

　　4. Copper-molybdenum separation pretreatment stage

　　Generally, copper-molybdenum separation processes fall into two main approaches: depressing molybdenum to float copper and depressing copper to float molybdenum. Given that molybdenite is more readily floated, the majority of operations adopt the approach of depressing copper to float molybdenum. However, when processing ores with high copper content and low molybdenum content, the approach of depressing molybdenum to float copper should be considered, as depressing copper can lead to significantly higher reagent costs. Moreover, molybdenite exhibits excellent floatability, and inorganic or small organic molecule inhibitors are often ineffective in this case. This has paved the way for the use of certain polymeric inhibitors, such as dextrin, starch, humic acid, and tannic acid.

　　Copper-molybdenum separation primarily involves pretreatment before separation, inhibition of copper minerals during separation, and subsequent re-enrichment after copper-molybdenum separation. The main pretreatment methods are as follows: :

　　 1) Concentrated mixed concentrate. The primary purpose is to remove residual reagents and frothers from the flotation copper-molybdenum mixed concentrate. During the second-phase reconstruction of the Unugtushan copper-molybdenum concentrator, Liu Zilong and his colleagues intensified the application of this pretreatment process, using a ceramic filter as the concentration equipment following copper-molybdenum mixed flotation. This approach effectively addressed the longstanding challenge of separating molybdenum ore, resulting in a concentrate with improved grade. 57. 75% molybdenum concentrate. Lei Guichun, on the other hand, uses a hydrocyclone to concentrate and de-mine the mixed copper-molybdenum concentrate from the Dexing Copper Mine, thereby increasing the grade of the molybdenum concentrate. 0. 63% , increased recovery rate 11. 14% Sodium sulfide consumption reduced. 32. 17% 。

　　 2) Heating methods. Heating the mixed concentrate can cause the collector on the mineral surface to decompose, breaking down the hydrophobic film and evaporating the frother from the slurry. As a result, the surface of copper minerals becomes oxidized, reducing their floatability and leading to inhibition, while having minimal impact on molybdenite, thereby achieving separation. Currently, the main heating methods include heaters, roasting, and steam blowing. It has been confirmed that globally approximately... 40% The copper-molybdenum concentrator employs a heat treatment process, which not only reduces the dosage of sodium sulfide but also significantly improves the beneficiation indicators.

　　 3) Add reagents—primarily oxidizing agents such as peroxides, ozone, chlorine, potassium permanganate, and oxygen—to oxidize the surface of copper minerals, rendering them hydrophilic and causing the adsorbed collectors to be oxidized and decomposed. When... pH For 10 ~ 11 , in the slurry O2 Copper sulfide can be oxidized to S2O32 — and thereby inhibiting it. Natarajan Researchers used electrochemical tests to verify that ozone effectively oxidizes and decomposes the collector on the chalcopyrite surface, and that it is more effective than oxygen.

　　Therefore, by controlling pulp conditions such as introducing oxygen and adjusting... pH The reagent can inhibit chalcopyrite to achieve copper suppression and molybdenum flotation. However, one point that should be noted is that the dosage of the oxidizing agent should not be excessive; otherwise, it could impair the inhibitory effect of sodium sulfide—a strongly reducing agent—in the subsequent copper-suppression and molybdenum-flotation stage.

　　5. Copper-molybdenum separation inhibition stage

　　After pretreatment, the copper-molybdenum separation process can be carried out. An important aspect of this process is the selection of flotation inhibitors. Commonly used inhibitors can be categorized into two types: inorganic and organic. Inorganic inhibitors mainly include Knox compounds, cyanides, and sodium sulfide, while organic inhibitors primarily consist of thiolacetates. These inhibitors can be used either individually or in combination.

　　 1) Cyanides—including sodium zinc cyanide and sodium ferrocyanide—are complex compounds of cyanide. They are primarily used as depressants for copper and iron sulfide ores, with the aim of disrupting xanthates and forming stable cyanide complexes. The effect is remarkably pronounced and highly efficient even in small doses. In the production application at the Jinduicheng Concentrator, sodium cyanide is added during the molybdenum flotation stage. 0. 05 ~ 0.06 kg/t , thus obtaining copper less than 0.5% molybdenum concentrate. However, due to its highly toxic nature—especially when used in conjunction with ores containing gold, silver, and other metals—the application of this method in ore-processing plants has been gradually declining.

　　 2) Sodium sulfide compounds—primarily sodium hydrosulfide, sodium sulfide, and ammonium sulfide—have been shown through research to exert their primary inhibitory effect via the hydrolysis of sulfides to produce [unspecified substance]. SH —. In actual production, sodium sulfide and sodium hydrosulfide are the most commonly used, for example, at the Dexing Copper Mine. Na2S When copper inhibition and molybdenum flotation are carried out, the beneficiation indicators are quite good. However, sodium sulfide is prone to oxidation and loses its effectiveness, and when used in excessive amounts, it reaches... 80 ~ 100 kg/t The proportion of pharmaceutical costs is quite high, accounting for a significant portion of the molybdenum selection costs. 85%。

　　Domestically, the Beijing Nonferrous Metallurgy Design and Research Institute has also chosen the Dexing Copper Mine for an industrial nitrogen-injection trial, which has reduced... 60. 55% Amount of sodium sulfide. It is worth noting that sodium sulfide and sodium cyanide can effectively inhibit chalcopyrite, but they have relatively poor inhibitory effects on large amounts of covellite and secondary covellite.

　　 4) Thioacetate salts—particularly thioacetic acid—exhibit excellent inhibition performance, require low dosages, cause minimal pollution, and offer high selectivity. Wan Shenghui et al. synthesized thioacetic acid via the sodium sulfide method and conducted industrial trials at the Dexing Copper Mine, achieving remarkable inhibition results and obtaining a molybdenum concentrate with a high grade. 51. 53% Molybdenum concentrate recovery rate 79. 89% , the copper content is only 0.32% 。

　　 5) A novel inhibitor. Jiang Yuren and colleagues synthesized a new inhibitor. DPS The tests show that it can significantly inhibit chalcopyrite and galena, but has little effect on molybdenite. The dosage is equivalent to that of sodium mercaptoacetate. 1/5 and sodium sulfide 1 /10 Moreover, it boasts good stability, a simple synthesis route, and low-cost raw materials. Yuan Zengwei, on the other hand, is researching novel inhibitors. CM1 , compared to mercaptoacetic acid, CM1 The inhibitory effect is more pronounced, and the dosage is lower. ( Reduce 20 g/L) It acts quickly and also has an inhibitory effect on the opposing lead ore.

　　6. Copper-Molybdenum Separation and Concentration Stage

　　After copper-molybdenum separation, the next steps involve molybdenum and copper beneficiation. Typically, molybdenum requires six stages of beneficiation to meet smelting requirements. Sometimes, a portion of molybdenum in the mixed flotation concentrate remains incompletely liberated, making regrinding an essential step. Zhang Hengwang improved the process for the Xiaosigou copper-molybdenum mine by introducing an additional regrinding stage prior to molybdenum beneficiation, ultimately achieving a high-grade molybdenum concentrate. 46.49% , the recovery rate is 92.26% , increased respectively compared to the un-reground state. 0.5% and 3.97% 。

　　Copper beneficiation is relatively straightforward and usually requires only a single stage of concentration. However, the asynchronous mixed flotation technique is worth noting: it involves first floating the easily floatable copper minerals, followed by intensified flotation of the more difficult-to-float copper minerals. ( Add mixed yellow medicine ) Mix the two-step copper concentrate, then re-grind and re-select.

　　7. New Technologies and Equipment for Copper-Molybdenum Separation

　　 1) Application of Flotation Columns

　　One of the advantages of flotation columns is their excellent recovery performance for fine particles that are difficult to float and for ores with high fine-silt content. Copper-molybdenum ores are characterized by fine-grained mineral inclusions, low-grade raw ore, and severe gangue minerals, which necessitate fine grinding particle sizes. Moreover, overgrinding is a serious issue, making separation increasingly challenging. Therefore, flotation columns can be used to replace some flotation machines, thereby improving separation efficiency. Currently, many types of flotation columns are in use, such as hydrocyclones. - Static microbubble flotation column, Jameson Flotation column, SFC Type-filled static flotation columns—during the reconstruction of a copper-molybdenum concentrator in Xinjiang, Ma Zilong and his colleagues adopted hydrocyclones. - The static microbubble flotation column serves as the primary equipment for copper-molybdenum mixed flotation, copper-molybdenum separation, and molybdenum concentrate upgrading. For copper-molybdenum separation roughing and copper-molybdenum mixed flotation, flotation cells are employed, forming a combined machine-column flotation system. The recovery indicator is the grade of the molybdenum concentrate. 50. 59% Molybdenum recovery rate 55. 96% Copper concentrate grade 21. 39% Copper recovery rate 91. 57% 。

　　 2) Application of Potential Regulation Technology

　　Electrochemical flotation also plays a significant role in the separation of copper and molybdenum. By controlling the pulp potential, sequential flotation of different sulfide minerals can be achieved. Chander The researchers conducted experiments using the potentiostatic method to electrochemically separate molybdenite from chalcocite. Krishnaswamy The reason why molybdenite exhibits naturally good floatability lies in its poor ability to conduct electrons—meaning that changes in the pulp potential have little effect on it. In contrast, chalcopyrite flotation requires an oxidizing pulp. Therefore, by externally controlling the pulp conditions, it is possible to influence the flotation behavior of these minerals. pH By adjusting the potential, chalcopyrite can be suppressed under a reducing atmosphere, while molybdenite remains floatable, thus enabling their separation.

　　8. Priority flotation technology for copper-molybdenum separation

　　For low-grade molybdenum-copper ores, while ensuring the grade and recovery rate of the molybdenum concentrate, it is also necessary to consider the comprehensive recovery of copper; in some cases, preferential flotation is more appropriate.

　　Dai Xinyu and colleagues conducted a study on a copper-molybdenum deposit in Tibet. In this deposit, secondary copper is severely developed, the oxidation rate is high, chalcopyrite is finely disseminated and heavily enclosed by gangue minerals, and molybdenite is distributed within fractures of the gangue and between mineral grains. The process adopted involves preferential flotation of molybdenum, followed by regrinding to separate copper from molybdenum; the molybdenum flotation tailings are then used to recover copper. The collector used for molybdenite minerals is kerosene. + Diesel, copper-molybdenum separation inhibitor DY08 Copper collector OSN-43 The selection result is the molybdenum grade in the molybdenum concentrate. 56. 16% , containing copper 0.071% , recovery rate 87. 58% Copper grade in copper concentrate 21. 84% , recovery rate 75. 93% Compared to mixed flotation, it saves costs. 10%。

　　9. Copper-molybdenum isomorphous flotation technology

　　Generally speaking, both preferential flotation and mixed flotation require high alkalinity. ( Lime ) To achieve the separation of copper, molybdenum, and sulfur, lime has an inhibitory effect on molybdenum, which is detrimental to molybdenum recovery. Equal floatability flotation can avoid such problems by using selective collectors and minimizing or eliminating the use of lime, thereby facilitating the separation of copper, molybdenum, and sulfur with minimal interference to the subsequent copper-molybdenum separation and molybdenum concentration processes, and ultimately leading to superior performance indicators. In a process study conducted on a certain copper-molybdenum ore, Hu Zhenfeng adopted the equal floatability flotation process. This ore has a low molybdenum grade and contains a slightly higher amount of pyrite.

　　10. Copper-Molybdenum Joint Beneficiation Technology

　　For most porphyry copper-molybdenum deposits where molybdenum and copper occur symbiotically, flotation is an effective processing method. However, for certain refractory copper-molybdenum ores, a combined beneficiation and metallurgical approach can be employed. For example, in Utah... Bingham Canyon The copper-molybdenum deposit is a porphyry-type copper-molybdenum deposit, with molybdenite and chalcopyrite as the main minerals. It contains high levels of talc and sericite, making the ore prone to mud formation. The conventional process involves mixed flotation—suppressing copper while floating molybdenum—followed by multiple stages of molybdenum concentration and reverse flotation of talc, ultimately yielding a molybdenum-rich concentrate. 52.3% Concentrate, followed by re-oxidation roasting—yet the recovery rate is only... 49.4% 。

　　11. Conclusion

　　Mixed flotation is applied in the separation of most copper-molybdenum ores. Sometimes, preferential flotation and isoflotation are also worth considering. The key lies in the fact that the grade and liberation size of copper and molybdenum in the raw ore significantly affect factors such as reagent dosage and grinding operations—thus determining both the economic cost of mineral processing and the quality of beneficiation indicators.

　　Effective pretreatment and the selection of inhibitors are critical steps in the reseparation of copper-molybdenum mixed flotation. Concentration, heating, and oxidation can effectively break down and remove reagents, but they should not cause... “ Secondary pollution ” Influencing copper-molybdenum separation, inhibitors such as Knox reagents, cyanides, and sodium sulfide exhibit good inhibitory effects, but they also present... “ Toxicity ” Alternatively, thiolacetate compounds, with their advantages of low dosage and high efficiency, represent a promising approach. The development of new pharmaceutical agents and combination therapies remains a worthwhile direction for further research.