Normal-pressure alkaline leaching method for molybdenum calcine

Abstract

The invention discloses a normal-pressure alkaline leaching method for molybdenum calcine, and belongs to the technical field of non-ferrous metal metallurgy. According to the scheme, sodium hydroxide is adopted as an alkaline leaching agent, the dosage of the alkaline leaching agent is 1.1 times of the theoretical amount of formed molybdate, the alkaline leaching agent is added to carry out alkaline leaching on molybdate under the normal pressure, solid-liquid separation is carried out after the first-time alkaline leaching is completed, and the molybdenum calcine is obtained; the method comprises the following steps: extracting molybdenum from a raw material, performing secondary alkaline leaching on a slag phase, performing oxygen blasting to oxidize low-valence molybdenum insoluble in alkali into high-valence molybdenum easy to leach, and recycling leaching water used in the secondary alkaline leaching, so that the smelting process is greatly shortened, the processing cost is reduced, and the leaching extraction rate of molybdenum in the raw material reaches 98% or above through two times of alkaline leaching; meanwhile, compared with a traditional process, no liquid or solid oxidizing agent is added, it is guaranteed that no new impurity element is introduced, equipment used in the scheme is simple, cost is reduced, and the recovery rate of molybdenum is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal smelting, and in particular is a method for alkaline leaching of molybdenum roasted sand at normal pressure. Background Art

[0002] The main chemical component of molybdenite is MoS2 sulfide mineral, in which the sulfide includes hexagonal and trigonal crystal structures. Molybdenite is the main mineral raw material for refining molybdenum and rhenium. For the smelting of molybdenite, the oxidation roasting-ammonia leaching process is widely used at home and abroad. Molybdenum roasted sand is obtained by oxidation roasting of molybdenite, and its main component is molybdenum trioxide. In addition, it also includes some calcium molybdate, copper molybdate, iron molybdate and molybdenum dioxide generated by incomplete oxidation.

[0003] Existing leaching processes include ammonia leaching process and alkali leaching process. When the ammonia leaching process is used, the molybdenum production process oxidizes the stable molybdenum disulfide in the molybdenite into soluble molybdenum trioxide through oxidative roasting, and then leaches with ammonia water. The leachate is purified, acidified, and other processes to obtain ammonium molybdate crystals, which are calcined to prepare molybdenum trioxide products. At the same time, the ammonia leaching process has a high requirement for the molybdenum content in the molybdenum ore when extracting molybdenum roasted sand. In the Chinese invention patent application No. CN202310442621.4, it is proposed to extract molybdenum roasted sand with ammonia. After leaching, it is pumped to an oxygen-pressure alkali-leaching filter press for filtration and washing. After alkali leaching, sodium molybdate is obtained by ammonium salt extraction, evaporation deammoniation, re-extraction, stripping and evaporation crystallization. When this method is used, oxygen-pressure alkali leaching is performed after ammonia leaching. Ammonia water is easily decomposed into ammonia gas, which is a flammable and explosive gas. The subsequent operation is to introduce oxygen into the kettle at 160°C and keep it warm at a pressure of 2.0MPa. This operation requires strict control of the composition of the output material between adjacent links, has high requirements for plant and equipment, and has production risks.

[0004] During the alkali leaching process, various oxidants need to be added to increase the leaching rate, which increases the cost and introduces new impurity elements, increasing the subsequent impurity removal process and impurity removal cost. The molybdenum in the leached slag is recovered by high-temperature oxygen pressure cooking in an autoclave. It requires many auxiliary materials, complex equipment, and high cost. High-pressure production requires higher production conditions, which increases production costs and increases production uncertainty. Therefore, how to simplify the leaching process of molybdenum roasted sand, reduce costs, and improve the recovery rate of molybdenum is an urgent problem to be solved. Summary of the invention

[0005] The invention provides a method for leaching roasted molybdenum sand at normal pressure with alkali leaching twice, and realizes efficient leaching of roasted molybdenum sand under normal pressure. The process of the invention does not generate waste water, reduces the cost of sewage treatment, does not add solid or liquid oxidant, does not introduce new impurity elements, and only uses sodium hydroxide for alkali leaching. Through the two alkali leachings and oxygen explosion, soluble molybdenum is completely leached, and low-priced molybdenum that is originally insoluble in alkali is oxidized into high-priced molybdenum that is easy to leach, thereby realizing efficient leaching of molybdenum. Compared with the traditional process, the smelting process is greatly shortened, the processing cost is reduced, and the leaching extraction rate of molybdenum in the raw material reaches more than 98%.

[0006] The present invention discloses a method for alkali leaching of molybdenum roasted sand at normal pressure, comprising the following steps:

[0007] S1: adding an oxidant to molybdenum roasted sand with a particle size of less than 150 μm for pre-activation treatment;

[0008] S2: washing the pre-activated molybdenum roasted sand multiple times with ionized water;

[0009] S3: using water and an alkaline leaching agent to modulate a primary alkaline leaching solution, mixing the primary alkaline leaching solution and the washed molybdenum roasted sand into a reactor, adjusting the pH value in the reactor to 8-10 at room temperature, starting stirring, and reacting the MoO3 anhydride in the molybdenum roasted sand with the primary alkaline leaching solution to form molybdate, and leaching for 90-120 minutes to obtain a mixture;

[0010] S4: adding an impurity remover to the mixture of S3, stirring and purifying for 30-60 minutes, so that a complex reaction occurs in the reactor to remove Fe2+, Fe3+, Al3+ and other ions in the solution;

[0011] S5: Add compressed air into the reactor, the compressed air pressure is 0.5 MPa, the reaction time is 30-90 minutes, and the reactor is kept stirring;

[0012] S6: introducing the material in the reaction kettle into a filter press to achieve solid-liquid separation, to obtain a primary liquid phase and a primary slag phase, wherein the primary liquid phase is the prepared sodium molybdate solution;

[0013] S7: using water and an alkaline leaching agent to prepare a secondary alkaline leaching solution, adding the secondary alkaline leaching solution to the primary slag phase, and controlling the solid-liquid ratio of the secondary alkaline leaching solution to be 1:3-1:4.5, controlling the temperature of the secondary alkaline leaching reaction to be 80-95°C, the solution pH value to be 9-13, and the leaching time to be 60-90 minutes;

[0014] S8: introducing the reactants after the secondary alkali leaching into the filter press again to achieve solid-liquid separation, thereby obtaining a secondary liquid phase and a secondary slag phase;

[0015] S9: Using 75-95° C. hot water to wash the secondary slag phase to obtain washing water and alkaline leached slag.

[0016] Preferably, the alkaline leaching agent in S2 is sodium hydroxide, and when the molybdenum roasted sand is sufficient, the ratio of the sodium hydroxide solution to the molybdate obtained in S2 is 1:1.

[0017] Preferably, the impurity remover component in S3 is magnesium chloride.

[0018] Preferably, in S5, compressed air is introduced into the reactor from multiple holes at the bottom and the reactor is kept in a stirring state.

[0019] Preferably, the secondary liquid phase obtained in S7 can be used as a primary alkaline leaching solution after adjusting the pH value of the solution.

[0020] Preferably, the rinsing water in S9 can be used as a secondary alkaline leaching solution, and the pH value of the solution needs to be adjusted during use.

[0021] Preferably, a 25% concentration of octanol + sulfonated kerosene mixture is added to the S3 as an extractant, and multi-stage countercurrent extraction is adopted. After the extraction is completed, it is washed with deionized water, and the raffinate is supplemented with alkali and then leached with high pressure once, and the molybdenum leaching effect is good.

[0022] Beneficial Effects

[0023] The atmospheric pressure alkali leaching method of the present invention achieves efficient molybdenum leaching without adding any oxidant, and has the following advantages:

[0024] 1. The present invention does not generate waste water during the production process, thus realizing the recycling of production water, saving water, reducing environmental protection costs and improving the extraction rate.

[0025] 2. The present invention requires less auxiliary materials for production, has a simple process, introduces less impurity elements, and is convenient for subsequent processing. At the same time, the present method does not use an ammonia leaching method to extract molybdenum roasted sand, which reduces production risks and eliminates the autoclave leaching process. It also avoids the problems of high energy consumption and low thermal efficiency in the process, simplifies the production process, shortens the smelting process, and reduces processing costs.

[0026] 3. The traditional ammonia leaching method has high requirements on the molybdenum trioxide raw material when extracting molybdenum. The present invention is suitable for molybdenum roasted sands with different molybdenum contents and can effectively extract the molybdenum element from medium and low-grade molybdenum roasted sands.

[0027] 4. The leaching extraction rate of molybdenum in the raw material of the present invention is more than 98%.

[0028] Through the above method, efficient leaching of molybdenum roasted sand can be directly achieved, so that the leaching process of molybdenum roasted sand does not require pickling pretreatment, the process is simple, the process is short, the molybdenum yield is high, and the high-pressure autoclave leaching process is cancelled, the process is simplified, and the cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0030] Figure 1 This is a schematic diagram of the process of molybdenum roasted sand alkali leaching at normal pressure; DETAILED DESCRIPTION

[0031] The present invention discloses a method for alkali leaching of molybdenum roasted sand at normal pressure, comprising the following steps:

[0032] S1: weighing molybdenum roasted sand with a particle size of less than 150 μm, slurrying, adding hydrogen peroxide for pre-activation treatment, so that the molybdenum in the molybdenum roasted sand is converted from a low-valent state to a high-valent state to improve the leaching rate of molybdenum;

[0033] S2: washing the pre-activated molybdenum roasted sand three times with ionized water;

[0034] S3: Prepare an alkaline leaching solution by adding the washed molybdenum roasted sand water and the alkaline leaching agent, adjust the pH value to 8-10 at room temperature, start stirring at the same time, and the leaching time is 90-120 minutes. The reaction equation is: XMo04+2Na0H=Me(0H)2+Na2Mo04 (X is Ca, Fe, Gu, etc.);

[0035] MoO3+2NaOH=Na2MoO4+H2O;

[0036] S4: adding impurity remover to the mixed solution after adding the alkaline leaching solution, stirring and purifying for 30-60 minutes, and the stirring time should not be too long;

[0037] S5: Add compressed air into the reactor, the compressed air is 0.5 MPa, the reaction time is 30-90 minutes, and the reactor is subjected to a slight positive pressure to react, which strengthens the reaction while reducing the equipment pressurization requirements and improving production safety. The compressed air enters the reactor to oxidize the low-valent metal ions, reducing their interference with the subsequent impurity removal process, making the impurity removal more complete. The reaction equation is:

[0038] 2MoS2+902+12Na0H=2Na2Mo04+4Na2S04+6H20

[0039] S6: The material in the reaction kettle is discharged, and filtered by sedimentation to achieve solid-liquid separation, to obtain a primary liquid phase and a primary slag phase, wherein the primary liquid phase is the prepared sodium molybdate solution;

[0040] S7: Add secondary alkali leaching solution to the primary slag phase, control the solid-liquid ratio to 1:3-4.5, control the temperature of the secondary alkali leaching reaction to 75-95℃, increase the temperature to increase the reaction rate, and the solution pH value to 9-13 to ensure that OH in the solution - ion concentration, leaching time is 60-90 minutes;

[0041] S8: filtering the reactants after the secondary alkali leaching to achieve solid-liquid separation to obtain a secondary liquid phase and a secondary slag phase;

[0042] S9: Use 75-95°C hot water to elute the secondary slag phase to obtain leaching water and alkaline leached slag.

[0043] According to the above method, 19 tons of molybdenum roasted sand was treated, with an average molybdenum content of 58.91%, 4.457 tons of alkaline leaching slag was produced, with an average molybdenum content of 4.33% in the slag, and the molybdenum leaching rate reached 98.276%.

[0044] The components of the sodium molybdate solution after alkali leaching were analyzed several times to obtain a comparative table of components in sodium molybdate 1.

[0045] Table 1: Comparative composition of sodium molybdate solution

[0046]

[0047] In some embodiments, the alkaline leaching agent in S3 is sodium hydroxide, and the amount used is 1.1 times the theoretical amount of molybdate to ensure sufficient reaction during one alkaline leaching process, wherein the ratio concentration of sodium hydroxide is set in the range of 15%-25%.

[0048] In some embodiments, the impurity remover component in S4 is magnesium chloride.

[0049] In some embodiments, in S5, compressed air is introduced from the bottom of the reactor through multiple holes and the reactor is kept in a stirring state to ensure that the solution in the reactor is fully oxidized.

[0050] In some embodiments, the secondary liquid phase obtained in S7 can be used as a primary alkali leaching solution. When used, the pH value of the solution needs to be adjusted to 8-10 to ensure the concentration of the primary alkali leaching solution reaction, so that the alkali leaching solution can be reused, the utilization rate of the alkali leaching solution can be improved, and the generation of waste liquid can be reduced.

[0051] In some embodiments, the rinse water in S9 can be used as a secondary alkaline leaching solution. When using it, the pH value of the solution needs to be adjusted to improve the utilization rate of the alkaline leaching solution and reduce the generation of waste liquid.

[0052] Compared with the traditional ammonia leaching method, when molybdenum roasted sand is subjected to ammonia leaching reaction to extract molybdenum, waste slags containing different molybdenum are subjected to multiple ammonia leaching reactions, and the molybdenum element obtained after the first and second ammonia leaching reactions at a reaction temperature of 85°C is measured. The molybdenum leaching rates obtained by the first and second ammonia leaching of the molybdenum-containing waste slag are shown in Table 2:

[0053] Table 2: Comparison of molybdenum leaching rate during primary and secondary ammonia leaching of molybdenum-containing waste slag

[0054]

[0055] When the alkali leaching method is used to extract molybdenum from molybdenum-containing waste slag by alkali leaching reaction, waste slags containing different molybdenum are subjected to multiple alkali leaching reactions, and the molybdenum element obtained after the first alkali leaching and the second alkali leaching reactions is measured, wherein the temperature is selected to be 45°C and 85°C for the second alkali leaching of the first alkali leaching liquid phase, and the molybdenum leaching rates obtained by the first alkali leaching and the second alkali leaching of the molybdenum-containing waste slag are shown in Table 3:

[0056] Table 3: Comparison of molybdenum leaching rate during primary and secondary alkaline leaching of molybdenum-containing waste slag

[0057]

[0058] By comparing Table 2 and Table 3, it can be seen that the molybdenum leaching rate after the secondary alkaline leaching in the method of the present invention is above 98%, which is higher than the molybdenum leaching rate when the ammonia leaching method is used in the prior art. At the same time, the present invention eliminates the problem of production safety when the ammonia leaching method is used for a single ammonia leaching, which causes the ammonia leaching agent to volatilize and generate ammonia gas due to high pressure and high temperature.

[0059] Example 1

[0060] 1: Take industrial molybdenum roasted sand as raw material, accurately weigh a certain amount of pre-treated molybdenum roasted sand, add deionized water to make slurry according to the optimized liquid-solid ratio, the molybdenum content is 45%, of which low-valent molybdenum oxide (MoO2) is 5% of the total molybdenum. First, add 6m water into the reactor. 3 , add liquid alkali 1 to prepare alkali leaching solution, when there is secondary alkali leaching solution, use the secondary alkali leaching solution instead of water, add 2-3 tons of molybdenum roasted sand, start stirring, react for 60 minutes, and adjust the pH value to 8;

[0061] 2: Add impurity remover to the mixed solution after adding the alkaline leaching solution, and stir and purify for 60 minutes;

[0062] 3: Add compressed air into the reactor, the compressed air is 0.5 MPa, and the reaction time is 60 minutes;

[0063] 4: Use a membrane filter press to self-circulate the alkali leaching slurry, drain the materials in the reactor, filter to achieve solid-liquid separation, and obtain a primary liquid phase and a primary slag phase. The primary liquid phase is the prepared sodium molybdate solution;

[0064] 5: Add 4-6m3 of water into the reactor 3 , use the rinse water instead of water when there is rinse water, add 0.5m of liquid caustic soda 3 , prepare secondary alkaline leaching solution.

[0065] 6: Add secondary alkali leaching to the primary slag phase, and control the solid-liquid ratio to 1:3, control the temperature of the secondary alkali leaching reaction to 45°C, adjust the solution pH to 9, and the leaching time to 60 minutes;

[0066] 7: Filter the reactants after the secondary alkali leaching to achieve solid-liquid separation to obtain a secondary liquid phase and a secondary slag phase;

[0067] 8: Use 80°C hot water to rinse the secondary slag phase to obtain leaching water and alkaline leached slag.

[0068] After the second alkaline leaching, the leaching extraction rate of molybdenum in the raw material reached 98.52%.

[0069] Example 2

[0070] 1: Use industrial molybdenum roasted sand as raw material, grind the molybdenum roasted sand to a particle size of less than 150μm, and the molybdenum content is 45%, of which low-valent molybdenum oxide accounts for 5% of the total molybdenum. First, add 6m water into the reactor. 3 , add the prepared alkaline leaching solution, when there is a secondary alkaline leaching liquid phase, use the secondary alkaline leaching liquid phase instead of water, add 2-3 tons of molybdenum roasted sand and start stirring, react for 60 minutes, and adjust the pH value to 8.5;

[0071] 2: Add magnesium persulfate to the mixed solution after adding the alkaline leaching solution, the amount of which is 2.5 times the molar amount of low-valent molybdenum in the molybdenum roasted sand, and stir and purify for 60 minutes;

[0072] 3: Add compressed air into the reactor, the compressed air is 0.5 MPa, and the reaction time is 60 minutes;

[0073] 4: Use a membrane filter press to self-circulate the alkali leaching slurry, drain the materials in the reactor, filter to achieve solid-liquid separation, and obtain a primary liquid phase and a primary slag phase. The primary liquid phase is the prepared sodium molybdate solution;

[0074] 5: Add 4-6m3 of water into the reactor 3 , use the rinse water instead of water when there is rinse water, add 0.5m of liquid caustic soda 3 , prepare secondary alkaline leaching solution.

[0075] 6: Add secondary alkali leaching to the primary slag phase, and control the solid-liquid ratio to 1:3, control the temperature of the secondary alkali leaching reaction to 75°C, adjust the solution pH to 9, and the leaching time to 60 minutes;

[0076] 7: Filter the reactants after the secondary alkali leaching to achieve solid-liquid separation to obtain a secondary liquid phase and a secondary slag phase;

[0077] 8: Use 75°C hot water to elute the secondary slag phase to obtain leaching water and alkaline leached slag.

[0078] After secondary alkaline leaching, the leaching extraction rate of molybdenum in the raw material reached 98.45%.

[0079] Example 3

[0080] An embodiment of the present invention is provided, such as Figure 1 As shown in Figure 1, 1: Industrial molybdenum roasted sand with a particle size of less than 150 μm is used as raw material, with a molybdenum content of 45%, of which low-valent molybdenum oxide accounts for 5% of the total molybdenum. First, add 10m of water into the reactor. 3 , add 1m of liquid alkali 3 Prepare alkaline leaching solution. If there is secondary alkaline leaching solution, use the secondary alkaline leaching solution instead of water, add 3 tons of molybdenum roasted sand, start stirring, react for 90 minutes, and adjust the solution pH to 13;

[0081] 2: Add impurity remover to the mixed solution after adding the alkaline leaching solution, and stir and purify for 60 minutes;

[0082] 3: Add compressed air into the reactor, the compressed air is 0.5 MPa, and the reaction time is 90 minutes;

[0083] 4: Use a membrane filter press to self-circulate the alkali leaching slurry, drain the materials in the reactor, filter to achieve solid-liquid separation, and obtain a primary liquid phase and a primary slag phase. The primary liquid phase is the prepared sodium molybdate solution;

[0084] 5: Add 6m3 of water into the reactor 3 , use the rinse water instead of water when there is rinse water, add 1.5m of liquid alkali 3 , prepare secondary alkaline leaching solution.

[0085] 6: Add secondary alkali leaching to the primary slag phase, and control the solid-liquid ratio to 1:3, control the temperature of the secondary alkali leaching reaction to 95°C, the solution pH value to 13, and the leaching time to 60 minutes;

[0086] 7: Filter the reactants after the secondary alkali leaching to achieve solid-liquid separation to obtain a secondary liquid phase and a secondary slag phase;

[0087] 8: Use 95°C hot water to elute the secondary slag phase to obtain leaching water and alkaline leached slag.

[0088] After the second alkaline leaching, the leaching extraction rate of molybdenum in the raw material reached 98.63%.

[0089] Example 4

[0090] An embodiment of the present invention is provided, such as Figure 1 As shown in the figure, 1: using industrial molybdenum roasted sand as raw material, the particle size of the molybdenum roasted sand is controlled to be below 150μm, the molybdenum content is 50%, and the low-valent molybdenum oxide is 5% of the total molybdenum. First, add 10m of water into the reactor. 3 , add 1m of liquid alkali 3 Prepare alkaline leaching solution. If there is secondary alkaline leaching solution, use the secondary alkaline leaching solution instead of water, add 3 tons of molybdenum roasted sand, start stirring, react for 90 minutes, and adjust the solution pH to 12;

[0091] 2: Add impurity remover to the mixed solution after adding the alkaline leaching solution, and add a 25% concentration of 2-octanol + sulfonated kerosene mixed solution as an extractant, use multi-stage countercurrent extraction, wash with deionized water after the extraction is completed, and stir and purify for 60 minutes;

[0092] 3: Add compressed air into the reactor, the compressed air is 0.5 MPa, and the reaction time is 90 minutes;

[0093] 4: Use a membrane filter press to self-circulate the alkali leaching slurry, drain the materials in the reactor, filter to achieve solid-liquid separation, and obtain a primary liquid phase and a primary slag phase. The primary liquid phase is the prepared sodium molybdate solution;

[0094] 5: Add 6m3 of water into the reactor 3 , use the rinse water instead of water when there is rinse water, add 1m of liquid alkali 3 , prepare secondary alkaline leaching solution.

[0095] 6: Add secondary alkali leaching to the primary slag phase, and control the solid-liquid ratio to 1:3, control the temperature of the secondary alkali leaching reaction to 85°C, the solution pH value to 12, and the leaching time to 60 minutes;

[0096] 7: Filter the reactants after the secondary alkali leaching to achieve solid-liquid separation to obtain a secondary liquid phase and a secondary slag phase;

[0097] 8: Use 85°C hot water to wash the secondary slag phase to obtain washing water and alkaline leaching slag. After the secondary alkaline leaching, the leaching extraction rate of molybdenum in the raw material reaches 98.92%.

Claims

1. A method for leaching molybdenum roasted sand at normal pressure with alkali, characterized in that: The following steps are involved: S1: adding an oxidant to molybdenum roasted sand with a particle size of less than 150 μm for pre-activation treatment; S2: washing the pre-activated molybdenum roasted sand multiple times with ionized water; S3: using water and an alkaline leaching agent to modulate a primary alkaline leaching solution, mixing the primary alkaline leaching solution and the washed molybdenum roasted sand into a reactor, adjusting the pH value in the reactor to 8-10 at room temperature, starting stirring, and reacting the MoO3 anhydride in the molybdenum roasted sand with the primary alkaline leaching solution to form molybdate, and leaching for 90-120 minutes to obtain a mixture; S4: adding impurity remover to the mixture of S3, stirring and purifying for 30-60 minutes, so that complex reaction occurs in the reactor to remove Fe2+, Fe3+, Al3+ ions in the solution; S5: Add compressed air into the reactor, the compressed air pressure is 0.5 MPa, the reaction time is 30-90 minutes, and the reactor is kept stirring; S6: introducing the material in the reaction kettle into a filter press for solid-liquid separation to obtain a primary liquid phase and a primary slag phase, wherein the primary liquid phase is the prepared sodium molybdate solution; S7: using water and an alkaline leaching agent to prepare a secondary alkaline leaching solution, adding the secondary alkaline leaching solution to the primary slag phase, and controlling the solid-liquid ratio of the secondary alkaline leaching solution to be 1:3-1:4.5, controlling the temperature of the secondary alkaline leaching reaction to be 80-95°C, the solution pH value to be 9-13, and the leaching time to be 60-90 minutes; S8: introducing the reactants after the secondary alkali leaching into the filter press again for solid-liquid separation to obtain a secondary liquid phase and a secondary slag phase; S9: Using 75-95° C. hot water to wash the secondary slag phase to obtain washing water and alkaline leached slag.

2. A method for leaching molybdenum roasted sand at normal pressure according to claim 1, characterized in that: The alkaline leaching agent in S2 is sodium hydroxide. When the molybdenum roasted sand is sufficient, the ratio of the sodium hydroxide solution to the molybdate obtained in S2 is 1:

1.

3. A method for leaching molybdenum roasted sand at normal pressure according to claim 1, characterized in that: The impurity remover component in S3 is magnesium chloride.

4. A method for leaching molybdenum roasted sand at normal pressure according to claim 1, characterized in that: In S5, compressed air is introduced into the reactor from the bottom of the reactor through multiple holes and the reactor is kept in a stirring state.

5. A method for leaching molybdenum roasted sand at normal pressure according to claim 1, characterized in that: The secondary liquid phase obtained in S7 can be used as a primary alkali leaching solution, and the pH value of the solution needs to be adjusted during use.

6. A method for leaching molybdenum roasted sand at normal pressure alkali according to claim 1, characterized in that: The rinsing water in S9 can be used as a secondary alkaline leaching solution, and the pH value of the solution needs to be adjusted during use.

7. A method for leaching molybdenum roasted sand at normal pressure according to claim 1, characterized in that: A 25% octanol + sulfonated kerosene mixture is added to the S3 as an extractant, and multi-stage countercurrent extraction is adopted. After the extraction is completed, it is washed with deionized water. After the raffinate is supplemented with alkali, the molybdenum leaching effect of one high-pressure leaching is good.

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