Efficient separation and purification method for molybdenum in molybdenite concentrate

Abstract

The invention discloses an efficient separation and purification method for molybdenum in molybdenite concentrate, and belongs to the technical field of hydrometallurgy. And the molybdenite concentrate is subjected to microwave treatment for 10-20 min at the power of 400-600 W and the temperature of 200-300 DEG C. The preparation method comprises the following steps: mixing the raw materials with an acid solution according to a solid-to-liquid ratio of 1: (3-5), heating to 180-250 DEG C, regulating oxygen partial pressure to 0.5-1.5 MPa, reacting for 2-3 hours, cooling, filtering and washing to obtain an acid leaching solution and acid leaching residues; mixing the acid leaching residues with alkali liquor according to the solid-to-liquid ratio of 1: (2-4), stirring and leaching for 1.5-2.5 hours at the temperature of 60-80 DEG C, and filtering and washing to obtain alkali leaching liquid and alkali leaching residues; mixing the acid leaching solution and the alkali leaching solution according to a ratio of (2-4): 1, adding an extracting agent according to a phase ratio of O / A of 1: (2-4), and extracting and splitting phases at room temperature to obtain a loaded organic phase and raffinate; mixing the loaded organic phase with a stripping agent according to a phase ratio O / A of (2-4): 1, and extracting and splitting phases at room temperature to obtain a back-extracted liquid and an extracted organic phase; and heating the back extraction solution until ammonium molybdate begins to crystallize, stopping heating, stirring to precipitate crystals, filtering, washing, drying, and calcining the crystals at 500-600 DEG C for 1.5-2.5 hours. According to the method, molybdenum in the acid leaching solution and the alkali leaching solution can be recovered synchronously, degradation and emulsification of an extracted organic phase are avoided, and the technological process is environmentally friendly and safe.

Description

Technical Field

[0001] This invention belongs to the field of hydrometallurgical technology, specifically relating to an efficient method for separating and purifying molybdenum from molybdenite concentrate. Background Technology

[0002] Molybdenum, as an important strategic metal, is characterized by its low abundance and high value, and is widely used in steel, chemical, electronics, aerospace, and other fields. Molybdenite (MoS2) is the main mineral source of molybdenum, and it usually contains a certain amount of copper, lead, and other sulfides. During oxidative roasting of molybdenite concentrate, MoS2 is oxidized to MoO3, releasing SO2 gas, which leads to high environmental costs for subsequent processing. Bioleaching is difficult to industrialize due to its long processing cycle, is only suitable for specific minerals, and has unstable recovery rates. Therefore, there is an urgent need to develop a new method for separating and purifying molybdenum from molybdenite concentrate that is widely applicable, has stable processes, high separation efficiency, low energy consumption, and environmental advantages, achieving efficient separation and enrichment of molybdenum to meet the needs of high-end manufacturing industries. Summary of the Invention

[0003] The purpose of this invention is to provide a highly efficient method for separating and purifying molybdenum from molybdenite concentrate.

[0004] The objective of this invention is achieved by providing a highly efficient method for the separation and purification of molybdenum from molybdenite concentrate, comprising the following steps: Oil removal from concentrate: Place molybdenum concentrate in a microwave reactor, set the power to 400~600W, the temperature to 200~300℃, and the processing time to 10~20min; Oxygen-pressure acid leaching: The degreased concentrate and acid solution are mixed into a slurry at a solid-liquid ratio of 1:3~5. Under closed conditions, the mixture is stirred and heated to 180~250℃. When the temperature reaches the set value, the oxygen partial pressure of the reaction system is adjusted to 0.5~1.5MPa. After reacting for 2~3 hours, the mixture is cooled. The leached material is then filtered and washed to obtain acid leaching solution and acid leaching residue. Alkaline leaching: The acid leaching residue and alkaline solution are mixed at a solid-liquid ratio of 1:2~4, heated to 60~80℃, and leached by stirring for 1.5~2.5h. After the reaction is completed, the leached material is filtered and washed to obtain alkaline leaching solution and alkaline leaching residue. Extraction: Mix the acid extract and the alkaline extract in a ratio of 2 to 4:1, neutralize, and then add the extractant in a ratio of O / A of 1:2 to 4. After extraction by shaking at room temperature, allow the mixture to stand and separate the phases to obtain the loaded organic phase and the raffinate. Back-extraction: The supported organic phase and the back-extraction agent ammonia water are mixed at a ratio of O / A = 2~4:1, and after extraction by shaking at room temperature, the phases are separated by standing. The back-extracted liquid and the extracted organic phase are obtained after separation. Evaporation crystallization: Heat the back-extraction solution until ammonium molybdate begins to crystallize, then stop heating, continue stirring to allow the crystals to precipitate, filter, wash, and dry to obtain ammonium molybdate crystals; Calcination decomposition: Ammonium molybdate crystals are calcined at 500~600℃ for 1.5~2.5h to obtain the target molybdenum trioxide.

[0005] The technical solution described in this invention has the following advantages compared with the prior art: (1) Adding a concentrate degreasing process before the oxygen pressure acid leaching process can avoid the combustion of organic matter caused by high temperature, high pressure and high oxygen conditions during the oxygen pressure acid leaching process, which could lead to safety accidents.

[0006] (2) By mixing the acid leaching solution and the alkaline leaching solution, the molybdenum in the acid leaching solution and the alkaline leaching solution can be recovered simultaneously, avoiding metal loss and waste. The molybdenum conversion rate is >97%.

[0007] (3) After the acid and alkali leaching solutions are mixed, the neutralization process can reduce the acidity of the acid leaching solution, avoid the degradation of the extracted organic phase under high acidity conditions, and avoid problems such as emulsification of the organic phase.

[0008] (4) Through this process, molybdenum can be recovered through a fully wet process, avoiding the generation of gases such as sulfur dioxide in the pyrometallurgical process, making the process green and environmentally friendly. Attached Figure Description

[0009] Figure 1 This is a process flow diagram of the technical solution described in this invention. Detailed Implementation

[0010] The present invention will be further described below, but this is not intended to limit the invention in any way. Any modifications or substitutions made based on the teachings of the present invention shall fall within the scope of protection of the present invention.

[0011] The efficient separation and purification method for molybdenum in molybdenite concentrate according to the present invention includes the following steps: Oil removal from concentrate: Place molybdenum concentrate in a microwave reactor, set the power to 400~600W, the temperature to 200~300℃, and the processing time to 10~20min; Oxygen-pressure acid leaching: The degreased concentrate and acid solution are mixed into a slurry at a solid-liquid ratio of 1:3~5. Under closed conditions, the mixture is stirred and heated to 180~250℃. When the temperature reaches the set value, the oxygen partial pressure of the reaction system is adjusted to 0.5~1.5MPa. After reacting for 2~3 hours, the mixture is cooled. The leached material is then filtered and washed to obtain acid leaching solution and acid leaching residue. Alkaline leaching: The acid leaching residue and alkaline solution are mixed at a solid-liquid ratio of 1:2~4, heated to 60~80℃, and leached by stirring for 1.5~2.5h. After the reaction is completed, the leached material is filtered and washed to obtain alkaline leaching solution and alkaline leaching residue. Extraction: Mix the acid extract and the alkaline extract in a ratio of 2 to 4:1, neutralize, and then add the extractant in a ratio of O / A of 1:2 to 4. After extraction by shaking at room temperature, allow the mixture to stand and separate the phases to obtain the loaded organic phase and the raffinate. Back-extraction: The supported organic phase and the back-extraction agent ammonia water are mixed at a ratio of O / A = 2~4:1, and after extraction by shaking at room temperature, the phases are separated by standing. The back-extracted liquid and the extracted organic phase are obtained after separation. Evaporation crystallization: Heat the back-extraction solution until ammonium molybdate begins to crystallize, then stop heating, continue stirring to allow the crystals to precipitate, filter, wash, and dry to obtain ammonium molybdate crystals; Calcination decomposition: Ammonium molybdate crystals are calcined at 500~600℃ for 1.5~2.5h to obtain the target molybdenum trioxide.

[0012] The molybdenite concentrate has a MoS2 content of 85-95%.

[0013] The acid solution is preferably 10-30% sulfuric acid.

[0014] The oxygen partial pressure is preferably 1.2 MPa.

[0015] The alkaline solution is preferably sodium hydroxide with a concentration of 30-50 g / L.

[0016] The extractant is either tributyl phosphate or an amine extractant.

[0017] The preferred extraction temperature is 25°C, and the extraction time is 15-25 min, preferably 20 min.

[0018] The preferred ratio for the back-extraction is O / A = 3:1.

[0019] The concentration of the ammonia water is 7~10 mol / L, preferably 8 mol / L.

[0020] The preferred temperature for the back-extraction is 25°C, and the time is 15-25 min, preferably 20 min.

[0021] During evaporation and crystallization, the preferred heating temperature is 80~90℃.

[0022] The preferred stirring speed is 50-100 rpm.

[0023] The preferred drying temperature is 70°C.

[0024] The preferred calcination temperature is 550°C and the time is 2 hours.

[0025] Example 1

[0026] Oil removal from concentrate: Place molybdenum concentrate in a microwave reactor, set the power to 500W, the temperature to 250℃, and the processing time to 15min; Oxygen-pressure acid leaching: The degreased concentrate is mixed with 20% sulfuric acid at a solid-liquid ratio of 1:4 and then placed in a titanium-lined pressure vessel. Under sealed conditions, the mixture is stirred and heated to 220°C. When the temperature reaches the set value, the oxygen partial pressure of the reaction system is adjusted to 1.2 MPa. After reacting for 2.5 hours, the mixture is cooled and the vessel is removed. The leached material is filtered and washed to obtain acid leaching solution and acid leaching residue.

[0027] Alkaline leaching: The acid leaching residue is mixed with 40 g / L sodium hydroxide at a solid-liquid ratio of 1:3, placed in a heat-collecting constant temperature stirrer, heated to 70°C, and leached for 2 hours. After the reaction is completed, the leached material is filtered and washed to obtain alkaline leaching solution and alkaline leaching residue.

[0028] Extraction: Mix the acid extract and the alkaline extract in a ratio of 3:1, neutralize, and place in a separatory funnel. Then, add the extractant (tributyl phosphate) to the separatory funnel according to a ratio of O / A of 1:3. Place the separatory funnel in a water bath constant temperature shaker and extract at 25°C for 20 minutes. After standing, allow the phases to separate. After the phase separation is complete, the loaded organic phase and the raffinate are obtained.

[0029] Back-extraction: The loaded organic phase and the back-extraction agent (8 mol / L ammonia water) were mixed at a ratio of O / A = 3:1 and placed in a water bath constant temperature shaker. After shaking and extraction at 25℃ for 20 min, the phases were allowed to separate. After the phase separation was completed, the back-extracted liquid and the extracted organic phase were obtained.

[0030] Evaporation and Crystallization: Pour the back-extraction solution into a beaker and place the beaker on an electric furnace lined with an asbestos mesh. Heat the furnace to 85°C to gradually evaporate the solvent, causing the concentration of ammonium molybdate to gradually increase until it reaches supersaturation. When ammonium molybdate begins to crystallize, stop heating and continue stirring at 80 rpm to allow crystal precipitation. After crystallization is complete, filter and wash to obtain wet ammonium molybdate. Place the wet material in a vacuum drying oven at 70°C to dry, obtaining ammonium molybdate crystals.

[0031] Calcination and decomposition: The dried ammonium molybdate crystals were placed in a muffle furnace and calcined at 550℃ for 2 hours to obtain the target molybdenum trioxide. Monitoring showed that the molybdenum conversion rate reached 99.2%.

[0032] Example 2

[0033] Oil removal from concentrate: Place molybdenum concentrate in a microwave reactor, set the power to 400W, the temperature to 200℃, and the processing time to 20min; Oxygen-pressure acid leaching: The degreased concentrate is mixed with 10% sulfuric acid at a solid-liquid ratio of 1:5 and then placed in a titanium-lined pressure vessel. Under sealed conditions, the mixture is stirred and heated to 180°C. When the temperature reaches the set value, the oxygen partial pressure of the reaction system is adjusted to 0.5 MPa. After reacting for 3 hours, the mixture is cooled and the vessel is removed. The leached material is filtered and washed to obtain acid leaching solution and acid leaching residue.

[0034] Alkaline leaching: The acid leaching residue is mixed with 30 g / L sodium hydroxide at a solid-liquid ratio of 1:4, placed in a heat-collecting constant temperature stirrer, heated to 60°C, and leached for 2.5 h. After the reaction is completed, the leached material is filtered and washed to obtain alkaline leaching solution and alkaline leaching residue.

[0035] Extraction: Mix the acid extract and the alkaline extract in a ratio of 2:1, neutralize, and place in a separatory funnel. Then, add the extractant (tributyl phosphate) to the separatory funnel according to a ratio of O / A of 1:2. Place the separatory funnel in a water bath constant temperature shaker and extract at 25°C for 15 minutes. After standing, allow the phases to separate. After the phase separation is complete, the loaded organic phase and the raffinate are obtained.

[0036] Back-extraction: The supported organic phase and the back-extraction agent (7 mol / L ammonia water) were mixed at a ratio of O / A = 2:1 and placed in a water bath constant temperature shaker. After shaking and extraction at 25℃ for 15 min, the phases were allowed to separate. After the phase separation was completed, the back-extracted liquid and the extracted organic phase were obtained.

[0037] Evaporation and Crystallization: Pour the back-extraction solution into a beaker and place the beaker on an electric furnace lined with an asbestos mesh. Heat the beaker to 80°C to allow the solvent to gradually evaporate, and the concentration of ammonium molybdate gradually increases until it reaches supersaturation. When ammonium molybdate begins to crystallize, stop heating and continue stirring at 50 rpm to allow crystal precipitation. After crystallization is complete, filter and wash to obtain wet ammonium molybdate. Place the wet material in a vacuum drying oven at 70°C to dry, obtaining ammonium molybdate crystals.

[0038] Calcination and decomposition: The dried ammonium molybdate crystals were placed in a muffle furnace and calcined at 500℃ for 2.5h to obtain the target molybdenum trioxide. Monitoring showed that the molybdenum conversion rate reached 97.0%.

[0039] Example 3

[0040] Oil removal from concentrate: Place molybdenum concentrate in a microwave reactor, set the power to 600W, the temperature to 300℃, and the processing time to 10min; Oxygen-pressure acid leaching: The degreased concentrate is mixed with 30% sulfuric acid at a solid-liquid ratio of 1:3 and then placed in a titanium-lined pressure vessel. Under sealed conditions, the mixture is stirred and heated to 250°C. When the temperature reaches the set value, the oxygen partial pressure of the reaction system is adjusted to 1.5 MPa. After reacting for 2 hours, the vessel is cooled and removed. The leached material is filtered and washed to obtain acid leaching solution and acid leaching residue.

[0041] Alkaline leaching: The acid leaching residue is mixed with 50 g / L sodium hydroxide at a solid-liquid ratio of 1:2, placed in a heat-collecting constant temperature stirrer, heated to 80°C, and leached for 1.5 h. After the reaction is completed, the leached material is filtered and washed to obtain alkaline leaching solution and alkaline leaching residue.

[0042] Extraction: Mix the acid extract and the alkaline extract in a ratio of 4:1, neutralize, and place in a separatory funnel. Then, add the extractant (tributyl phosphate) to the separatory funnel according to a ratio of O / A of 1:4. Place the separatory funnel in a water bath constant temperature shaker and extract at 25°C for 25 min. After standing, allow the phases to separate. After the phase separation is complete, the loaded organic phase and the raffinate are obtained.

[0043] Back-extraction: The loaded organic phase and the back-extraction agent (10 mol / L ammonia water) were mixed at a ratio of O / A = 4:1 and placed in a water bath constant temperature shaker. After shaking and extraction at 25℃ for 25 min, the phases were allowed to separate. After the phase separation was completed, the back-extracted liquid and the extracted organic phase were obtained.

[0044] Evaporation and Crystallization: Pour the back-extraction solution into a beaker and place the beaker on an electric furnace lined with an asbestos mesh. Heat the furnace to 90°C to gradually evaporate the solvent, causing the concentration of ammonium molybdate to gradually increase until it reaches supersaturation. When ammonium molybdate begins to crystallize, stop heating and continue stirring at 100 rpm to allow crystal precipitation. After crystallization is complete, filter and wash to obtain wet ammonium molybdate. Place the wet material in a vacuum drying oven at 70°C to dry, obtaining ammonium molybdate crystals.

[0045] Calcination and decomposition: The dried ammonium molybdate crystals were placed in a muffle furnace and calcined at 600℃ for 1.5h to obtain the target molybdenum trioxide. Monitoring showed that the molybdenum conversion rate reached 98.2%.

Claims

1. A method for efficient separation and purification of molybdenum from molybdenite concentrate, characterized in that, Includes the following steps: Oil removal from concentrate: Place molybdenum concentrate in a microwave reactor, set the power to 400~600W, the temperature to 200~300℃, and the processing time to 10~20min; Oxygen-pressure acid leaching: The degreased concentrate and acid solution are mixed into a slurry at a solid-liquid ratio of 1:3~5. Under closed conditions, the mixture is stirred and heated to 180~250℃. When the temperature reaches the set value, the oxygen partial pressure of the reaction system is adjusted to 0.5~1.5MPa. After reacting for 2~3 hours, the mixture is cooled. The leached material is then filtered and washed to obtain acid leaching solution and acid leaching residue. Alkaline leaching: The acid leaching residue and alkaline solution are mixed at a solid-liquid ratio of 1:2~4, heated to 60~80℃, and leached by stirring for 1.5~2.5h. After the reaction is completed, the leached material is filtered and washed to obtain alkaline leaching solution and alkaline leaching residue. Extraction: Mix the acid extract and the alkaline extract in a ratio of 2 to 4:1, neutralize, and then add the extractant in a ratio of O / A of 1:2 to 4. After extraction by shaking at room temperature, allow the mixture to stand and separate the phases to obtain the loaded organic phase and the raffinate. Back-extraction: The supported organic phase and the back-extraction agent ammonia water are mixed at a ratio of O / A = 2~4:1, and after extraction by shaking at room temperature, the phases are separated by standing. The back-extracted liquid and the extracted organic phase are obtained after separation. Evaporation crystallization: Heat the back-extraction solution until ammonium molybdate begins to crystallize, then stop heating, continue stirring to allow the crystals to precipitate, filter, wash, and dry to obtain ammonium molybdate crystals; Calcination decomposition: Ammonium molybdate crystals are calcined at 500~600℃ for 1.5~2.5h to obtain the target molybdenum trioxide.

2. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The acid solution is 10-30% sulfuric acid.

3. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The oxygen partial pressure is 1.2 MPa.

4. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The alkaline solution is sodium hydroxide at a concentration of 30-50 g / L.

5. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The extractant is either tributyl phosphate or an amine extractant.

6. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The extraction temperature was 25℃ and the time was 15~25min.

7. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The concentration of the ammonia water is 7~10 mol / L.

8. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The back-extraction temperature is 25°C, and the time is 15~25 min.

9. The efficient separation and purification method for molybdenum in molybdenite concentrate according to claim 1, characterized in that, The drying temperature is 70°C.

10. The method for efficient separation and purification of molybdenum from molybdenite concentrate according to claim 1, characterized in that, The calcination temperature was 550℃ and the time was 2 hours.

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