A method for preparing molybdenum trioxide from molybdenite

Abstract

The application discloses a method for preparing molybdenum trioxide from molybdenite, and the molybdenite is soaked in acid to remove impurities, and refined molybdenite is obtained through filtration; the refined molybdenite is high-temperature oxidized and roasted, and after the end, sodium molybdate solution or hydrogen peroxide is used to selectively dissolve molybdenum from molybdenum calcine, the obtained molybdenum solution is contacted with cation exchange resin or cation extraction agent, and after impurity removal, a pure molybdenum solution is obtained. The pure molybdenum solution is placed in an autoclave, and after adding molybdenum trioxide powder and a control agent, thermal decomposition is carried out, and molybdenum trioxide is obtained. After filtration, washing and drying of the molybdenum trioxide, molybdenum trioxide powder is obtained.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of molybdenum metallurgy, and relates to a method for preparing molybdenum trioxide from molybdenite. BACKGROUND

[0002] Currently, the mainstream molybdenum smelting process is to oxidize and roast molybdenite to convert it into molybdenum trioxide calcine, and then to extract molybdenum through wet leaching. There are two main schemes for wet leaching of molybdenum calcine: the first scheme is to use ammonia water, which can dissolve molybdenum trioxide to obtain ammonium molybdate solution. In this process, impurities such as tungsten and copper in the molybdenum calcine will also be dissolved out. The ammonium molybdate solution needs to be purified and impurities removed, and then the ammonium molybdate product can be prepared. The ammonium molybdate crystals also need to be further calcined to prepare molybdenum trioxide. The second scheme is to use sodium hydroxide solution to leach the molybdenum calcine to obtain sodium molybdate solution, and then use ion exchange or solvent extraction method to extract molybdenum, and then use ammonium chloride or ammonia water to desorb or back-extract pure ammonium molybdate solution, and further crystallize to obtain ammonium molybdate product.

[0003] Although the current mainstream molybdenum smelting method can effectively extract and prepare ammonium molybdate product from molybdenite, these methods can only produce ammonium molybdate, and it is inevitable to use ammonia (ammonium) reagents, which cannot avoid the emission of ammonia-nitrogen wastewater and cause pollution problems. In addition, in fact, ammonium molybdate crystals cannot be directly used as materials, and the next step is to calcine them to obtain molybdenum trioxide powder, which will also produce ammonia gas pollution in the process.

[0004] Therefore, the traditional mainstream molybdenum smelting process cannot solve the problem of ammonia-nitrogen pollution.

[0005] Based on the above analysis, a method for preparing molybdenum trioxide from molybdenite which can overcome the process complexity, long process and large environmental pollution in the prior art is urgently needed in the industry. SUMMARY

[0006] In order to solve the above problems, the application provides a method for preparing molybdenum trioxide powder from molybdenite, which does not use ammonia (ammonium) reagents, has no ammonia-nitrogen pollution, and directly prepares molybdenum trioxide powder product from molybdenum solution. The application is realized by the following technical means:

[0007] The application discloses a method for preparing molybdenum trioxide from molybdenite, comprising:

[0008] (1) using an acid solution to acid leach and remove impurities from molybdenite, filtering, and obtaining refined molybdenite which is oxidized and roasted at high temperature to obtain molybdenum trioxide for standby;

[0009] (2) selectively leaching molybdenum from the molybdenum trioxide to obtain a molybdenum solution for standby;

[0010] (3) The molybdenum solution is contacted with a cation exchange resin or a cationic extractant to remove impurity cations in the solution, and a pure molybdenum solution is obtained for standby use;

[0011] (4) The pure molybdenum solution is placed in an autoclave, and molybdenum trioxide powder and a control agent are added for heating decomposition. The decomposition product is filtered, washed, and dried to obtain molybdenum trioxide powder.

[0012] Further, the acid solution in step (1) includes sulfuric acid or hydrochloric acid; the concentration of the acid solution is 0.5-10 mol / L; the acid leaching temperature is 50-150°C, and the acid leaching time is 0.5-6 h; and the high-temperature roasting temperature is 500-700°C.

[0013] Further, the selective dissolution of molybdenum from molybdenum trioxide in step (2) includes selective dissolution of molybdenum using a sodium molybdate solution or selective dissolution of molybdenum using a hydrogen peroxide solution.

[0014] Further, the selective dissolution of molybdenum using a sodium molybdate solution includes:

[0015] The selective dissolution of molybdenum from molybdenum trioxide using a sodium molybdate solution has a molybdenum concentration of 10-200 g / L in the sodium molybdate solution, a solution pH of 5-10, a reaction temperature of 50-100°C, and a reaction time of 0.5-6 h. After the reaction, a sodium polymolybdate solution is obtained. Then, 0.5-3 times the molar amount of hydrogen peroxide is added to the solution, and a sodium peroxomolybdate solution is obtained.

[0016] Further, the selective dissolution of molybdenum using a hydrogen peroxide solution includes:

[0017] The selective dissolution of molybdenum from molybdenum calcine using a hydrogen peroxide solution has a hydrogen peroxide mass fraction of 5-30%, an acid solution concentration of 0-10 mol / L, a reaction temperature of 25-60°C, and a reaction time of 0.5-6 h. After the reaction, a peroxomolybdate solution is obtained.

[0018] Further, the amount of molybdenum trioxide powder added in step (4) is 0-5% of the mass of the pure molybdenum solution.

[0019] The amount of the control agent added is 0-20% of the mass of the pure molybdenum solution.

[0020] Further, the control agent includes but is not limited to:

[0021] sulfuric acid, hydrochloric acid, nitric acid, citric acid, oxalic acid, tartaric acid, thiourea, ethanol, ethylene glycol, and propanol.

[0022] Further, the heating decomposition temperature in step (4) is 120-300°C, and the decomposition time is 0.5-24 h.

[0023] The application also discloses the molybdenum trioxide prepared according to any of the above methods.

[0024] The application has the following beneficial effects:

[0025] (1) The application uses sodium molybdate or hydrogen peroxide to leach the molybdenum trioxide in the calcine, and selectively dissolves the molybdenum trioxide, thereby reducing the dissolution of impurities.

[0026] (2) The application can directly prepare the molybdenum trioxide from the leaching solution, and has a short process and a high recovery rate.

[0027] (3) The molybdenum extraction process of the application does not use ammonia nitrogen reagents, and has no ammonia nitrogen wastewater discharge, and is clean and pollution-free. DETAILED DESCRIPTION

[0028] Example 1

[0029] A method for preparing molybdenum trioxide from molybdenite, comprising:

[0030] (1) using 2 mol / L sulfuric acid solution to acid leach the molybdenite to remove impurities, filtering, the acid leaching temperature is 90°C, the acid leaching time is 2h, the obtained refined molybdenite is oxidized and calcined at 550°C to obtain molybdenum trioxide calcine for standby;

[0031] (2) using sodium molybdate solution to selectively dissolve molybdenum from the molybdenum trioxide, the concentration of molybdenum in the sodium molybdate solution is 80g / L, the pH of the solution is 9, the reaction temperature is 80°C, the reaction time is 1h, after the reaction is completed, a sodium polymolybdate solution is obtained, then hydrogen peroxide is added in a quantity of 1 times the molar quantity of molybdenum in the solution, the obtained molybdenum solution is sodium peroxomolybdate solution, and the leaching rate of the molybdenum trioxide is 99.2%;

[0032] (3) contacting the sodium peroxomolybdate solution with a cationic extractant to remove impurity cations in the solution, to obtain a pure sodium peroxomolybdate solution for standby;

[0033] (4) placing the pure sodium peroxomolybdate solution in an autoclave, adding 1% of molybdenum trioxide powder based on the mass of the pure sodium peroxomolybdate solution and 10% of sulfuric acid based on the mass of the pure sodium peroxomolybdate solution for heating and decomposition, the heating and decomposition temperature is 150°C, the decomposition time is 6h, and the decomposition product is filtered, washed and dried to obtain molybdenum trioxide powder, and the precipitation rate of the molybdenum trioxide is 99.8%.

[0034] Example 2

[0035] A method for preparing molybdenum trioxide from molybdenite, comprising:

[0036] (1) using 10 mol / L hydrochloric acid solution to molybdenum ore acid leaching, filtration, acid leaching temperature is 100 ℃, acid leaching time is 1.5 h, the obtained molybdenum concentrate at 700 ℃ oxidation roasting, get molybdenum trioxide calcine for standby;

[0037] (2) using hydrogen peroxide to molybdenum calcine for selective leaching of molybdenum, hydrogen peroxide mass fraction is 10%, the acid solution concentration is 2 mol / L, the reaction temperature is 50 ℃, the reaction time is 2 h, after the reaction the obtained molybdenum solution is peroxymolybdate solution, the molybdenum trioxide leaching rate is 99.6%;

[0038] (3) the peroxymolybdate solution is contacted with cation exchange resin, and the impurity cations in the solution are removed, to obtain peroxymolybdate solution for standby;

[0039] (4) pure peroxymolybdate solution is placed in an autoclave, and 1% ethylene glycol by mass of pure peroxymolybdate solution is added for heating decomposition, the heating decomposition temperature is 180 ℃, the decomposition time is 4 h, the decomposition product is filtered, washed and dried to obtain molybdenum trioxide powder, and the molybdenum trioxide precipitation rate is 99.5%.

[0040] Example 3

[0041] A method for preparing molybdenum trioxide from molybdenite, comprising:

[0042] (1) using 3 mol / L sulfuric acid and hydrochloric acid mixed solution to molybdenite acid leaching, filtration, acid leaching temperature is 90 ℃, acid leaching time is 6 h, the obtained molybdenum concentrate at 500 ℃ oxidation roasting, get molybdenum trioxide calcine for standby;

[0043] (2) using sodium molybdate solution to molybdenum trioxide for selective leaching of molybdenum, the concentration of molybdenum in sodium molybdate solution is 160 g / L, the solution pH is 5, the reaction temperature is 90 ℃, the reaction time is 2 h, after the reaction the obtained sodium polymolybdate solution, then according to the molar amount of molybdenum in the solution 2 times to add hydrogen peroxide, the reaction obtained molybdenum solution is sodium peroxymolybdate solution, the molybdenum trioxide leaching rate is 99.6%;

[0044] (3) the sodium peroxymolybdate solution is contacted with cation exchange resin, and the impurity cations in the solution are removed, to obtain pure sodium peroxymolybdate solution for standby;

[0045] (4) pure sodium peroxymolybdate solution is placed in an autoclave, and 5% molybdenum trioxide powder by mass of pure sodium peroxymolybdate solution is added for heating decomposition, the heating decomposition temperature is 250 ℃, the decomposition time is 6 h, the decomposition product is filtered, washed and dried to obtain molybdenum trioxide powder, and the molybdenum trioxide precipitation rate is 99.7%.

[0046] Comparative example 1

[0047] A method for preparing molybdenum trioxide from molybdenite, comprising:

[0048] (1) using 3 mol / L of sulfuric acid and hydrochloric acid mixed solution to molybdenite acid leaching impurities, filtration, acid leaching temperature is 90℃, acid leaching time is 6h, the obtained molybdenite is oxidized at 500℃, and the molybdenum trioxide calcine is prepared for use;

[0049] (2) using hydrogen peroxide to selectively dissolve molybdenum from molybdenum calcine, the mass fraction of hydrogen peroxide is 10%, the concentration of acid solution is 2mol / L, the reaction temperature is 50℃, and the reaction time is 2h, after the reaction is completed, the obtained molybdenum solution is peroxymolybdate solution, and the molybdenum trioxide leaching rate is 67%.

[0050] (3) the peroxymolybdate solution is contacted with cation exchange resin to remove impurity cations in the solution, and the peroxymolybdate solution is prepared for use;

[0051] (4) the pure peroxymolybdate solution is placed in an autoclave, 1% of ethylene glycol by mass of pure peroxymolybdate solution is added for heating decomposition, the heating decomposition temperature is 180℃, the decomposition time is 4h, and the decomposition product is filtered, washed and dried to obtain molybdenum trioxide powder, and the molybdenum trioxide precipitation rate is 99.6%.

[0052] Comparative example 2

[0053] A method for preparing molybdenum trioxide from molybdenite, comprising:

[0054] (1) using 3 mol / L of sulfuric acid and hydrochloric acid mixed solution to molybdenite acid leaching impurities, filtration, acid leaching temperature is 90℃, acid leaching time is 6h, the obtained molybdenite is oxidized at 500℃, and the molybdenum trioxide calcine is prepared for use;

[0055] (2) using sodium molybdate solution to selectively dissolve molybdenum from molybdenum trioxide, the concentration of molybdenum in the sodium molybdate solution is 100g / L, the solution pH is 4, the reaction temperature is 80℃, and the reaction time is 1h, after the reaction is completed, the obtained is sodium polymolybdate solution;

[0056] (3) the sodium molybdate solution is contacted with cation extractant to remove impurity cations in the solution, and the pure sodium molybdate solution is prepared for use;

[0057] (4) the pure sodium molybdate solution is placed in an autoclave, 1% of molybdenum trioxide powder by mass of pure peroxymolybdate sodium solution, and 10% of sulfuric acid by mass of pure peroxymolybdate sodium solution are added for heating decomposition, the heating decomposition temperature is 150℃, the decomposition time is 6h, and the decomposition product is filtered, washed and dried to obtain molybdenum trioxide powder, and the molybdenum trioxide precipitation rate is 45%.

[0058] The above are only the preferred embodiments of the present application, and do not limit the present application in any way. Any simple modification, change and equivalent structural change made according to the technical essence of the present application to the above embodiments are still within the protection scope of the technical solution of the present application.

Claims

1. A method for preparing molybdenum trioxide from molybdenite, comprising: (1) Use acid solution to remove impurities from molybdenite by acid leaching and filtration. The refined molybdenite is then oxidized and roasted at high temperature to obtain molybdenum trioxide for later use. (2) Selective dissolution of molybdenum trioxide was performed, specifically by selective dissolution of molybdenum using sodium molybdate solution, and a molybdenum solution was prepared for use. (3) Contact the molybdenum solution with a cation exchange resin or a cation extractant to remove impurity cations from the solution and obtain a pure molybdenum solution for later use. (4) A pure molybdenum solution is placed in an autoclave, and molybdenum trioxide powder and a regulator are added for heating and decomposition. The decomposition product is filtered, washed, and dried to obtain molybdenum trioxide powder; wherein: Step (2) involves selectively dissolving molybdenum using sodium molybdate solution, specifically using sodium molybdate solution to selectively dissolve molybdenum trioxide. The concentration of molybdenum in the sodium molybdate solution is 10~200g / L, the pH of the solution is 5~10, the reaction temperature is 50~100℃, the reaction time is 0.5~6h, and after the reaction is completed, a sodium molybdate solution is obtained. Then, hydrogen peroxide is added at 0.5~3 times the molar amount of molybdenum in the solution. The molybdenum solution obtained from the reaction is a sodium peroxymolybdate solution. The amount of molybdenum trioxide powder added in step (4) is 0-5% of the mass of the pure molybdenum solution; the amount of the regulator added is 0-20% of the mass of the pure molybdenum solution; and the amounts of molybdenum trioxide powder and regulator added are not both 0. Regulators include: Sulfuric acid, hydrochloric acid, nitric acid, citric acid, oxalic acid, tartaric acid, thiourea, ethanol, ethylene glycol, propanol.

2. The method according to claim 1, wherein: The acid solution in step (1) includes: sulfuric acid or hydrochloric acid; The concentration of the acid solution is 0.5~10 mol / L; The acid leaching temperature is 50~150℃, and the acid leaching time is 0.5~6h; The high-temperature oxidation roasting temperature is 500~700℃.

3. The method according to claim 1, wherein: The heating and decomposition temperature in step (4) is 120~300℃, and the decomposition time is 0.5~24h.