Method for efficiently leaching molybdenum in high-lead molybdenum calcine or molybdenum flue dust under normal pressure
By employing wet grinding and high-alkalinity foam leaching technology, the leaching problem of lead molybdate in high-lead molybdenum calcined sand and molybdenum flue ash has been solved, achieving efficient molybdenum recovery, reducing production costs and auxiliary material consumption, and is suitable for molybdenum recovery under normal pressure conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-29
- Publication Date
- 2026-04-03
AI Technical Summary
Existing technologies struggle to efficiently leach molybdenum, especially lead molybdate, from high-lead molybdenum calcined sand and molybdenum flue dust in alkaline systems, resulting in low molybdenum recovery rates. Furthermore, high-pressure leaching presents significant energy losses and safety hazards, while traditional processes are complex and consume large amounts of auxiliary materials.
The slurry was processed in a ball mill using a wet grinding method that involved grinding and leaching simultaneously. High-alkalinity foam leaching was achieved by generating bubbles through an ejector. The Venturi effect was used to increase the contact area between the gas and the particles. Combined with stirring with high alkalinity and oxygen, solid-liquid separation was achieved, yielding a high-alkalinity sodium molybdate solution and leaching residue.
It significantly improves the leaching rate of molybdenum, reduces the molybdenum content in the slag to below 0.8%, and achieves a leaching rate of over 98%. The process is simple, low-cost, and allows for the reuse of auxiliary materials, making it suitable for the leaching of lead molybdate from molybdenum roasted sand using the wet alkaline leaching method.
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Abstract
Description
Technical Field
[0001] This application relates to the field of metal smelting technology, and in particular to a method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum roasted sand or molybdenum flue ash under normal pressure. Background Technology
[0002] Molybdenum is an important non-ferrous metal, widely used in fertilizer production, petrochemicals, steel manufacturing, and aerospace due to its excellent rigidity, wear resistance, thermal and electrical conductivity, and corrosion resistance. Molybdenum resources are relatively abundant in nature, but exist in complex forms. More than 20 types of molybdenum have been discovered, mainly including molybdenite, molybdenite ore, molybdenite-tungsten-calcium ore, and molybdenite-lead ore, among which molybdenite is the most widely distributed and has the greatest industrial value. As the primary source of molybdenum, molybdenite currently accounts for 80% of all molybdenum production. The common industrial technique for extracting molybdenum metal involves pyrometallurgically roasting molybdenum concentrate to produce molybdenum roasted sand, followed by wet leaching of molybdenum trioxide to extract molybdenum. However, the flue gas generated during the roasting process contains significant amounts of molybdenum and rhenium, which need to be recovered and utilized. Because molybdenite contains other metallic impurities such as Ca, Pb, Fe, Cu, and Zn, these metals combine with molybdenum trioxide to form molybdates at certain temperatures during roasting. In alkaline systems, some molybdates are difficult to leach, such as lead molybdate, leading to a reduced molybdenum leaching rate and affecting molybdenum recovery. Therefore, how to leach high-lead molybdenum roasted ore has become an urgent problem to solve.
[0003] In alkaline systems, the main decomposition method for lead molybdate is currently sodium sulfide decomposition. Yang Shaowen, Cao Yaohua, et al., in their study "Study on Leaching Molybdenum Oxide from Low-Grade Lead-Molybdenum Coarse Concentrate," stated that using low-grade lead-molybdenum coarse ore as raw material, with a sodium sulfide dosage of 2.5 times, the molybdenum leaching rate was only 85%, which is very low. Some literature reports that high-pressure leaching can achieve higher leaching rates for low-grade molybdenum roasted ore. Hu Lei, Xiao Liansheng, et al., in their experimental study "Experimental Study on High-Pressure Leaching of Molybdenum from High-Impurity Low-Grade Molybdenum Roasted Ore with Soda," pointed out that using low-grade, high-impurity molybdenum roasted ore as raw material, and employing high-pressure leaching with soda to extract molybdenum, when the soda dosage was 30% of the ore sample, the magnesium oxide dosage was 2.5% of the ore sample, the temperature was 160℃, the liquid-to-solid ratio was 2:1, and the leaching time was 90 min, the molybdenum leaching rate could reach 95.9%. The disadvantages of high-pressure soda leaching include high energy loss due to high temperature and pressure, low production capacity, significant safety hazards, and it is not suitable for high-lead molybdenum roasted ore. Yang Yong, Yao Yuan, et al., in their study "The Influence of High-Copper, Low-Grade Molybdenum Concentrate on Molybdenum Processing Production," pointed out that using a roasting-acid leaching-ammonia leaching process to treat low-grade molybdenum concentrate resulted in a molybdenum leaching rate of 95.37%. This process is complex; acid washing can dissolve lead molybdate, but the combined use of acid washing and ammonia leaching leads to high auxiliary material consumption, and some molybdenum is lost into the solution during acid leaching, resulting in a lower molybdenum recovery rate. Summary of the Invention
[0004] In view of this, this application provides a method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum roasted sand or molybdenum flue ash under normal pressure, which can effectively overcome the defects of the prior art.
[0005] This application provides a method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum roasted sand or molybdenum flue ash under normal pressure, comprising the following steps:
[0006] High-lead molybdenum calcined sand or molybdenum flue ash raw materials are mixed with liquid alkali to form a slurry. Wet grinding and leaching are carried out in a ball mill using a simultaneous grinding and leaching method. After a period of reaction, the slurry is transferred out, and liquid alkali or caustic soda flakes are added to the slurry to increase the alkalinity. High-alkalinity leaching is carried out in a reaction vessel equipped with an ejector. A large number of bubbles are generated during the high-speed jetting of fluid through the ejector, resulting in high-alkali foam leaching. After reaction under certain conditions, solid-liquid separation is carried out to obtain a high-alkali sodium molybdate solution and leaching residue.
[0007] Preferably, the ball mill is a three-barrel vibrating ball mill with a motor power of 18KW and a grinding capacity of up to 300kg per hour. The mill is filled with steel balls of different sizes, with diameters of 2cm and 3cm respectively, and the three barrels have diameters of 600mm, 400mm, and 400mm respectively.
[0008] Preferably, the wet milling leaching conditions are: solid-liquid ratio of 1:3, temperature of 50-60℃, residual alkali of 20g / l, reaction time of 2 hours, and particle grinding to below 200 mesh.
[0009] Preferably, the high alkalinity is 40~100g / l of residual alkali.
[0010] Preferably, the foam leaching is performed by using the Venturi effect to generate negative pressure by spraying high-speed fluid through an ejector, thereby achieving full mixing of gas and slurry and generating a large number of bubbles. The ejector is equipped with a circulating pump with a power of 17.5KW and a circulation frequency of 25-35Hz. Three porous discharge pipes are connected below the ejector nozzle to spray the liquid at high speed and evenly in all directions.
[0011] Preferably, the high-alkali foam leaching conditions are: a solid-liquid ratio of 1:8, a temperature of 70~80℃, oxygen introduction, continuous stirring, and a reaction time of 8 hours.
[0012] Preferably, the high-lead-molybdenum calcined sand comprises the following components by mass percentage: Mo 31.33%, Ca 2.45%, Pb 1.81%, and impurity elements 64.41%.
[0013] Preferably, the molybdenum flue ash comprises the following components by mass percentage: Mo 13~17.35%, Ca 0.19~1.01%, Pb 8.03~9%, and impurity elements 72.64~78.78%.
[0014] This application employs high-alkalinity leaching of high-lead molybdenum calcined sand or molybdenum flue ash. The high-lead molybdenum calcined sand or molybdenum flue ash raw material is mixed with liquid alkali to form a slurry. Wet leaching is carried out in a ball mill using a simultaneous grinding and leaching method. After a period of reaction, the slurry is discharged, and liquid alkali or caustic soda flakes are added to the slurry to increase alkalinity. Foam leaching is then performed in a reactor equipped with an ejector using high alkalinity. After reaction under certain conditions, solid-liquid separation is performed to obtain a high-alkalinity sodium molybdate solution and leaching residue. The specific reaction principle can be explained by the following equation:
[0015] 2MoO2 + O2 = 2MoO3
[0016] MoO3 + 2NaOH = Na2MoO4 + H2O
[0017] PbMoO4 + 2NaOH = Pb(OH)2 + Na2MoO4
[0018] Compared with the prior art, this application has the following advantages:
[0019] The wet milling leaching method not only refines the particles and increases the reaction area, allowing molybdenum in the particles to better combine with the reactants, but also lowers the activation energy of the reaction through the collision of particles with the ball mill, making the reaction easier to proceed. Furthermore, the jetting action of the jet injector generates a large number of bubbles, increasing the contact area between oxygen and particles, ensuring sufficient oxidation of molybdenum in the slurry and facilitating leaching. Experimental results show that compared with conventional low-alkali leaching of high-lead-molybdenum calcined sand, the leaching rate of high-lead-molybdenum calcined sand obtained by the wet milling leaching and high-alkali foam leaching methods of this application is significantly improved, and the molybdenum content in the slag is significantly reduced. As the alkalinity increases, the molybdenum content in the slag continuously decreases, and the leaching rate continuously increases. When the alkalinity increases from residual alkali of 40 g / L to residual alkali of 100 g / L, the molybdenum content in the secondary slag of high-lead-molybdenum calcined sand decreases from 1.5% to 0.8%, and the leaching rate increases from 94% to 98%. Similarly, the molybdenum content in the secondary slag of molybdenum flue ash decreases from 3% to below 0.8%, and the leaching rate increases from 85% to 98%. This invention successfully solves the problem of lead molybdate leaching from molybdenum calcined sand and flue ash. It offers advantages such as simple process, convenient operation, low production cost, reusable auxiliary materials, and high metal recovery rate, making it suitable for situations where lead molybdate affects the leaching rate in wet alkaline leaching of molybdenum calcined sand. Detailed Implementation
[0020] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.
[0021] Unless otherwise specified, the experimental methods used in the embodiments of this application are all conventional methods.
[0022] In the following examples, unless otherwise specified, all raw materials can be obtained by commercial purchase or conventional methods.
[0023] Example 1
[0024] The method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum roasted sand or molybdenum flue ash under normal pressure in this embodiment includes the following steps:
[0025] Take 125 kg of high-lead molybdenum calcined sand in four portions. The main components of the high-lead molybdenum calcined sand are Mo 31.33%, Ca 2.45%, Pb 1.81%, with the remainder being impurities. Add 0.375 mg of each portion to the appropriate amount of calcined sand. 3 Water was added, and caustic soda flakes were added to bring the residual alkali to 20 g / L. The mixture was stirred and heated to 60°C. Once the temperature reached the specified level, the slurry was transferred to a ball mill, and the mill was turned on and reacted for 2 hours at maximum frequency. The slurry was then discharged, and water was added to bring the solid-liquid ratio to 1:8. Caustic soda flakes were added sequentially to bring the residual alkali to 40 g / L, 60 g / L, 80 g / L, and 100 g / L, respectively. The slurry was then transferred to a reaction vessel, and oxygen was introduced into the vessel. The circulation pump was turned on, and the frequency was set to 30 Hz, allowing the slurry to enter from the top and exit from the bottom of the ejector. The reaction was carried out at 80°C for 8 hours. The slurry was then filtered, and the filter cake was washed three times with hot water until the hot water completely covered the filter cake. The Mo concentration and alkalinity in the leachate were measured, and the molybdenum content in the residue was determined. The results showed that the molybdenum content in the residue increased with increasing alkalinity, becoming 1.51%, 1.16%, 0.76%, and 0.66%, respectively. When the residual alkali reaches 100 g / L, the leaching rate reaches 98.7%.
[0026] Example 2
[0027] The method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum roasted sand or molybdenum flue ash under normal pressure in this embodiment includes the following steps:
[0028] Weigh out 125 kg of molybdenum flue ash in four portions. The main components of the molybdenum flue ash are Mo: 13.98%, Ca: 0.19%, Pb: 8.47%, with the remainder being impurities. Add 0.375 mg of each portion to the appropriate amount of ash. 3Water was added, and caustic soda flakes were added to bring the residual alkali to 20 g / L. The mixture was stirred and heated to 60°C. Once the temperature reached the specified level, the slurry was transferred to a ball mill, and the mill was turned on and reacted for 2 hours at maximum frequency. The slurry was then discharged, and water was added to bring the solid-liquid ratio to 1:8. Caustic soda flakes were added sequentially to bring the residual alkali to 40 g / L, 60 g / L, 80 g / L, and 100 g / L, respectively. The slurry was then transferred to a reaction vessel, and oxygen was introduced into the vessel. The circulation pump was turned on, and the frequency was set to 30 Hz, allowing the slurry to enter from the top and exit from the bottom of the ejector. The reaction was carried out at 80°C for 8 hours. The slurry was then filtered, and the filter cake was washed three times with hot water until the hot water completely submerged the filter cake. The Mo concentration and alkalinity in the leaching were measured, and the molybdenum content in the residue was determined. The results showed that the molybdenum content in the residue increased with increasing alkalinity to 3.11%, 2.01%, 1.15%, and 0.71%, respectively. Molybdenum flue dust is more difficult to leach than molybdenum calcined sand due to its low grade and high impurity content. When the residual alkali reaches 100 g / L, the leaching rate reaches 98.3%.
[0029] Example 3
[0030] The method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum roasted sand or molybdenum flue ash under normal pressure in this embodiment includes the following steps:
[0031] Weigh out 125 kg of molybdenum flue ash in four portions. The main components of the molybdenum flue ash are Mo: 13.98%, Ca: 0.19%, Pb: 8.47%, with the remainder being impurities. Add 0.375 mg of each portion to the appropriate amount of ash. 3 Water was added, and caustic soda flakes were added to bring the residual alkali to 20 g / L. The mixture was stirred and heated to 60°C. Once the temperature reached the specified level, the slurry was transferred to a ball mill, and the mill was turned on and reacted for 2 hours at maximum frequency. The slurry was then discharged, and water was added to bring the solid-liquid ratio to 1:8. Caustic soda flakes were added sequentially to bring the residual alkali to 40 g / L, 60 g / L, 80 g / L, and 100 g / L, respectively. The slurry was then transferred to a reaction vessel, and oxygen was introduced into the vessel. The circulation pump was turned on, and the frequency was adjusted to 30 Hz, allowing the slurry to enter from the top and exit from the bottom of the ejector. The reaction was carried out at 80°C for 8 hours. The slurry was then filtered, and the filter cake was washed three times with hot water until the hot water completely submerged the filter cake. The Mo concentration and alkalinity in the leachate were measured, and the molybdenum content in the residue was determined. The results showed that the molybdenum content in the leached residue was 2.69%, 1.11%, 0.84%, and 0.77%, respectively, with a leaching rate of 98.1%.
[0032] The data of the leaching residue obtained from the above embodiments are shown in Table 1:
[0033] Table 1
[0034]
[0035] The results show that the process described in this application can effectively leach molybdenum from high-lead calcined sand and high-lead flue ash through wet grinding leaching and foam high-alkali leaching, and reduce the molybdenum content in the slag to below 0.8%, with a leaching rate of over 98%.
[0036] Conclusion: Wet milling leaching and foam high-alkali leaching can effectively reduce the molybdenum content in the leaching residue of high-lead molybdenum roasted sand and molybdenum flue ash. Under sufficient alkali conditions, the molybdenum content in the leaching residue of high-lead molybdenum roasted sand can be reduced to below 0.8%, with a leaching rate of over 98%. The leaching conditions are as follows: wet milling leaching uses an alkalinity of 20 g / L, a solid-liquid ratio of 1:3, a temperature of 50-60℃, and a reaction time of 2 hours; high-alkali foam leaching uses an alkalinity of 100 g / L, a solid-liquid ratio of 1:8, a temperature of 70-80℃, and a reaction time of 8 hours.
[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.
Claims
1. A method for high-efficiency alkaline leaching of molybdenum from high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure, characterized in that, Includes the following steps: High-lead molybdenum calcined sand or molybdenum flue ash raw materials are mixed with liquid alkali to form a slurry. Wet grinding and leaching are carried out in a ball mill using a simultaneous grinding and leaching method. After a period of reaction, the slurry is transferred out, and liquid alkali or caustic soda flakes are added to the slurry to increase the alkalinity. High-alkalinity leaching is carried out in a reaction vessel equipped with an ejector. A large number of bubbles are generated during the high-speed jetting of fluid through the ejector, resulting in high-alkali foam leaching. After reaction under certain conditions, solid-liquid separation is carried out to obtain a high-alkali sodium molybdate solution and leaching residue.
2. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The ball mill is a three-barrel vibrating ball mill with a motor power of 18KW. It can grind up to 300kg per hour. The mill contains steel balls of different diameters: 2cm and 3cm. The three barrels have diameters of 600mm, 400mm, and 400mm respectively.
3. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The wet milling leaching conditions are as follows: solid-liquid ratio of 1:3, temperature of 50-60℃, residual alkali of 20g / l, reaction time of 2 hours, and particle grinding to below 200 mesh.
4. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The high alkalinity refers to a residual alkali of 40~100g / l.
5. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The foam leaching process utilizes the Venturi effect to generate negative pressure by spraying high-speed fluid through an ejector, achieving thorough mixing of gas and slurry and producing a large number of bubbles. The ejector is equipped with a circulating pump with a power of 17.5KW and a circulation frequency of 25-35Hz. Three porous discharge pipes are connected below the ejector nozzle to ensure that the liquid is sprayed at high speed and evenly in all directions.
6. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The high-alkali foam leaching conditions are as follows: solid-liquid ratio of 1:8, temperature of 70~80℃, oxygen introduction, continuous stirring, and reaction time of 8 hours.
7. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The high-lead molybdenum calcined sand comprises the following components by mass percentage: Mo 31.33%, Ca 2.45%, Pb 1.81%, and impurity elements 64.41%.
8. The method for high-efficiency alkaline leaching of high-lead molybdenum calcined sand or molybdenum flue ash under normal pressure according to claim 1, characterized in that, The molybdenum flue ash comprises the following components by mass percentage: Mo 13~17.35%, Ca 0.19~1.01%, Pb 8.03~9%, and impurity elements 72.64~78.78%.