Method for recovering cobalt and molybdenum from waste containing molybdenum and cobalt

Abstract

The invention discloses a method for recovering cobalt and molybdenum from waste containing molybdenum and cobalt, which is characterized by comprising the following steps of: adding waste powder containing molybdenum and cobalt after crushing and ball milling into an autoclave, adding pure water according to a liquid-solid mass ratio of (5: 1)-(10: 1), stirring and slurrying, heating to 140-180 DEG C, introducing oxygen into the autoclave, and adding a sodium carbonate solution with the concentration of 100-150g / L; controlling the oxygen partial pressure to be 0.6-1.5 MPa and the total pressure in the autoclave to be 1.2-2.7 MPa, and carrying out heat preservation reaction for 2-4 hours; and finally, carrying out solid-liquid separation on the reacted slurry to obtain molybdenum-containing feed liquid and cobalt slag. Compared with the prior art that high-temperature oxidation is conducted firstly and then wet leaching treatment is conducted, energy consumption is reduced, the technological process is saved, the brought environmental problem is avoided, and meanwhile separation and recycling of cobalt and molybdenum are achieved.

Description

Technical Field

[0001] The invention belongs to the field of hydrometallurgy and provides a method for recovering cobalt and molybdenum from molybdenum-cobalt waste. Background Art

[0002] At present, domestic cobalt resources have the problems of low grade and high separation difficulty, resulting in a high degree of dependence on foreign cobalt raw materials. In the face of the urgent demand for cobalt resources, recovering cobalt elements from various cobalt-containing wastes has become an important breakthrough in alleviating the shortage of cobalt raw materials.

[0003] There are many waste materials containing cobalt, such as waste cobalt-molybdenum hydrogenation catalysts, cobalt-molybdenum cemented carbides, etc. The existing methods for recycling waste cobalt-molybdenum catalysts and cobalt-molybdenum cemented carbides mainly include high-temperature oxidation, mechanical crushing, electrolysis, acid leaching, sodium roasting, zinc melting, etc. Among them, since the process technology of high-temperature oxidation has been developed more maturely, it has a strong pertinence for separating the main elements tungsten and cobalt in cemented carbides. Therefore, high-temperature oxidation is generally used to separate and recover cobalt and tungsten elements in waste cemented carbides. However, the high-temperature oxidation method also has the disadvantages of high energy consumption and certain pollution to the environment. Summary of the invention

[0004] The object of the present invention is to provide a method for recovering cobalt and chromium from molybdenum-cobalt waste, aiming to solve the problems existing in the prior art in the above-mentioned background technology.

[0005] To this end, the present invention adopts the following technical solutions: A method for recovering cobalt and molybdenum from molybdenum-cobalt waste materials comprises the following steps: adding crushed and ball-milled molybdenum-cobalt waste powder into a pressure autoclave, adding pure water at a liquid-solid mass ratio of 5:1-10:1, stirring and slurrying, heating to 140-180°C, introducing oxygen into the pressure autoclave, and adding a sodium carbonate solution with a concentration of 100-150 g / L; controlling the oxygen partial pressure to 0.6-1.5 MPa, the total pressure in the pressure autoclave to 1.2-2.7 MPa, and keeping the temperature for reaction for 2-4 hours; and finally performing solid-liquid separation on the slurry after the reaction to obtain a molybdenum-containing liquid and cobalt slag.

[0006] The molybdenum-cobalt waste has a cobalt content of 35% to 45%, a molybdenum content of 5% to 15%, and a waste powder particle size of less than 300 meshes.

[0007] The amount of sodium carbonate solution added is based on controlling the pH value of the reaction end point to be 11-12.

[0008] The molybdenum content in the molybdenum-containing liquid is 5-30 g / L, and the cobalt content is less than 0.0005 g / L.

[0009] The cobalt content in the cobalt slag is 38-55%, and the molybdenum content is less than 0.1%.

[0010] The present invention has the following beneficial effects: The molybdenum-cobalt waste powder is treated by pressurized oxygen alkaline leaching. Compared with the prior art method of first high-temperature oxidation and then wet leaching, it reduces energy consumption, saves process flow and avoids the environmental problems caused, while achieving the separation and recycling of cobalt and molybdenum. DETAILED DESCRIPTION

[0011] Embodiment 1 (1) The molybdenum-cobalt waste was crushed into powder using a crushing ball mill. The sample was analyzed and the cobalt content was 44.4% and the molybdenum content was 11.3%.

[0012] (2) Take 500g of powder and add it into the autoclave, add 4L of pure water, stir and slurry, set the heating temperature to 180℃, and start heating. When the temperature reaches 180℃, the pressure in the autoclave is 1.17Mpa, introduce oxygen, and control the oxygen partial pressure to 0.7Mpa, the total pressure is 1.87Mpa, maintain the total pressure in the autoclave unchanged, slowly add 2L of 150g / L sodium carbonate solution, continue to react for 3h, and after the reaction is completed The leached slurry was filtered to obtain 5.92L of molybdenum-containing liquid and wet cobalt slag; the molybdenum-containing liquid was sampled and tested, and the molybdenum content was 9.53g / L and the cobalt content was 0.0003g / L; the wet cobalt slag was filtered and washed with 2L of pure water for multiple times, and then placed in an oven for drying at 100°C and weighed to be 478.3g. The cobalt content was 46.44% and the molybdenum content was 0.05% after sampling and testing. Calculated on the slag, the molybdenum leaching rate was greater than 99%.

[0013] (3) Acid and reducing agent are added to the cobalt slag for leaching, and after solid-liquid separation, a cobalt salt solution is obtained, which can be used as a raw material for downstream processes such as the production of cobalt sulfate crystals, cobalt chloride crystals, etc.

[0014] Embodiment 2 (1) The molybdenum-cobalt waste was crushed into powder using a crushing ball mill. The sample was analyzed and the cobalt content was 38.7% and the molybdenum content was 8.43%.

[0015] (2) Take 500g of powder and add it into the autoclave, add 4L of pure water, stir, and slurry. Set the heating temperature to 160℃ and start heating. When the temperature reaches 160℃, the pressure in the autoclave is 0.98Mpa. Oxygen is introduced and the oxygen partial pressure is controlled to 0.6Mpa. The total pressure is 1.58Mpa. Maintain the total pressure in the autoclave unchanged, slowly add 1.5L of 120g / L sodium carbonate solution, continue the reaction for 3h, and the reaction is over. After that, the leached slurry was filtered to obtain 5.45L of molybdenum-containing liquid and wet cobalt slag; the molybdenum-containing liquid was sampled and tested, and the molybdenum content was 7.73g / L and the cobalt content was 0.0004g / L; the wet cobalt slag was filtered and washed with 2L of pure water for multiple times, and then put into an oven for drying at 100°C, and weighed to be 486.4g. The cobalt content was sampled and tested, and the molybdenum content was 39.78%, and the molybdenum content was 0.03%. Calculated on the slag, the molybdenum leaching rate was greater than 99%.

[0016] (3) Acid and reducing agent are added to the cobalt slag for leaching, and after solid-liquid separation, a cobalt salt solution is obtained, which can be used as a raw material for downstream processes such as the production of cobalt sulfate crystals, cobalt chloride crystals, etc.

Claims

1. A method for recovering cobalt and molybdenum from molybdenum-cobalt waste, characterized in that: The method comprises the following steps: adding crushed ball-milled molybdenum-cobalt-containing waste powder into a pressure autoclave, adding pure water at a liquid-solid mass ratio of 5:1-10:1, stirring to form a slurry, heating to 140-180° C., introducing oxygen into the pressure autoclave, and adding a sodium carbonate solution with a concentration of 100-150 g / L; controlling the oxygen partial pressure to be 0.6-1.5 MPa, and the total pressure in the pressure autoclave to be 1.2-2.7 MPa, and carrying out a heat preservation reaction for 2-4 hours; and finally performing solid-liquid separation on the slurry after the reaction to obtain a molybdenum-containing liquid and cobalt slag.

2. A method for recovering cobalt and molybdenum from molybdenum-cobalt waste as claimed in claim 1, characterized in that: The molybdenum-cobalt waste contains 35% to 45% cobalt and 5% to 15% molybdenum. The particle size of the waste powder after treatment is less than 300 meshes.

3. A method for recovering cobalt and molybdenum from molybdenum-cobalt waste as claimed in claim 1, characterized in that: The amount of sodium carbonate solution added is based on controlling the pH value of the reaction end point to be 11-12.

4. A method for recovering cobalt and molybdenum from molybdenum-cobalt waste as claimed in claim 1, characterized in that: The molybdenum content in the molybdenum-containing liquid is 5-30 g / L, and the cobalt content is less than 0.0005 g / L.

5. A method for recovering cobalt and molybdenum from molybdenum-cobalt waste as claimed in claim 1, characterized in that: The cobalt content in the cobalt slag is 38-55%, and the molybdenum content is less than 0.1%.