A process for separating and recovering molybdenum and nickel from spent hydrogenation catalyst

Abstract

The present application belongs to the technical field of heavy metal-containing hazardous waste treatment, and specifically discloses a method for separating and recovering molybdenum and nickel from waste hydrogenation catalysts. First, the waste catalyst is placed in a tubular furnace for air roasting to generate molybdenum trioxide and nickel oxide. When a certain temperature is reached, the molybdenum trioxide begins to sublimate, and the gasified molybdenum trioxide is recovered through a condenser. Subsequently, the remaining roasting products are placed in a reactor, and a certain concentration of chlorine dioxide gas is introduced to react with the nickel oxide at room temperature to generate nickel chloride, which is then recovered. The method has a simple and efficient process, does not produce wastewater, and has obvious application value.

Description

Technical Field

[0001] This invention belongs to the field of heavy metal hazardous waste treatment technology, and specifically discloses a method for separating and recovering molybdenum and nickel from waste hydrogenation catalysts. Background Technology

[0002] Catalysts are indispensable chemical substances in the chemical industry. The annual consumption of industrial catalysts is constantly increasing, with a significant proportion used in the petroleum refining sector, where hydrogenation catalysts are a primary application. Hydrogenation catalysts that have been used for a long time will become deactivated due to carbon buildup, heavy metal deposition, and sintering of the active phase. While oxidation regeneration can restore some activity, repeated treatments often result in irrecoverable activity, ultimately rendering the catalysts unusable. Improper disposal of spent hydrogenation catalysts can cause environmental pollution. Spent hydrogenation catalysts contain various valuable metals such as Mo and Ni, representing important secondary resources. Molybdenum and nickel, along with their alloys, have wide applications in aerospace and other fields. Therefore, recovering molybdenum, nickel, and other metals from spent hydrogenation catalysts for recycling is of great significance for economic, environmental, and social benefits.

[0003] Patent CN 101435027B discloses a method for recovering high-purity molybdenum from molybdenum-containing waste catalysts. This method first mixes the waste catalyst with alkaline substances and magnesium oxide in a specific ratio and calcines it at high temperature. The calcined product is then subjected to pressurized water leaching, followed by stepwise precipitation to obtain ammonium molybdate. This method introduces various foreign impurity ions (magnesium and sodium) and generates a large amount of acidic wastewater, increasing the environmental burden. Patent CN 101724758A discloses a method for recovering molybdenum from molybdenum-containing waste catalysts. This method first cools and pulverizes the oxidized and calcined waste catalyst, then further mixes it with sodium carbonate and sodium bicarbonate for calcination. The calcined product is mixed with an acidic solution containing sulfuric acid, nitric acid, and citric acid and filtered. Ammonia is added to the filtrate to adjust the pH before filtration. Ammonia is then added to the ammonium molybdate precipitate and the pH is adjusted again. The filtered ammonium molybdate precipitate is dried to recover the ammonium molybdate product. This method is complex to operate, consumes a large amount of reagents, generates a large amount of waste liquid, and increases the difficulty of subsequent treatment. Summary of the Invention

[0004] The purpose of this invention is to provide a simple, efficient method for recovering molybdenum and nickel that requires minimal equipment and does not generate saline wastewater. To achieve this objective, the invention employs the following technical solution:

[0005] A method for recovering molybdenum and nickel from spent hydrogenation catalyst containing molybdenum and nickel includes the following steps:

[0006] (1) The waste hydrogenation catalyst was placed in a tubular furnace for air roasting, molybdenum was oxidized and sublimated, and molybdenum trioxide was recovered after passing through a condenser.

[0007] The calcination temperature in the air environment is 800℃-1100℃, and the calcination time is 1-3h.

[0008] The preferred calcination temperature is 1000℃, and the preferred calcination time is 2 hours.

[0009] (2) The remaining roasted product obtained in step (1) is placed in a reactor and chlorine dioxide gas is introduced. Nickel oxide reacts with chlorine dioxide at room temperature to obtain nickel chloride product.

[0010] The concentration of chlorine dioxide gas is 50%-70%; the gas-solid molar ratio of chlorine dioxide gas to the remaining roasting product is 1:1-3:1; and the reaction time at room temperature is 1-3 hours.

[0011] The preferred concentration of chlorine dioxide gas is 60%, the preferred gas-solid molar ratio of chlorine dioxide gas to the remaining roasted product is 2:1, and the preferred reaction time at room temperature is 2 hours.

[0012] The beneficial effects of this invention are as follows:

[0013] (1) The present invention uses calcination to improve the valence state transformation of molybdenum, which is then converted into an oxide and sublimated and condensed for recovery; nickel is converted into nickel chloride by introducing chlorine dioxide gas and then recovered.

[0014] (2) The method of the present invention is simple, economical and efficient, and has important practical value and good application prospects. Attached image description:

[0015] Figure 1 XRD patterns of MoO3 and NiCl2 products.

[0016] Figure 2 This is a process flow diagram of the present invention for recovering molybdenum and nickel from spent catalysts.

[0017] Figure 3 This is a technical roadmap for recovering molybdenum and nickel from spent catalysts according to the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to embodiments. These embodiments are intended to illustrate the present invention and not to further limit the present invention.

[0019] Example 1

[0020] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 800°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 97.7%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.8%. In this example, the recovery rates of molybdenum and nickel were 96.5% and 99.6%, respectively.

[0021]

[0022]

[0023] Example 2

[0024] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 900°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 98.6%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.8%. In this example, the recovery rates of molybdenum and nickel were 97.4% and 99.6%, respectively.

[0025] Example 3

[0026] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.8%. In this example, the recovery rates of molybdenum and nickel were 99.4% and 99.6%, respectively.

[0027] Example 4

[0028] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1100°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.2%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.8%. In this example, the recovery rates of molybdenum and nickel were 98.7% and 99.6%, respectively.

[0029] Example 5

[0030] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 1 hour. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 96.4%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.8%. In this example, the recovery rates of molybdenum and nickel were 95.3% and 99.6%, respectively.

[0031] Example 6

[0032] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 3 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.5%. The remaining calcined product obtained after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.8%. In this example, the recovery rates of molybdenum and nickel were 99.1% and 99.6%, respectively.

[0033] Example 7

[0034] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 50% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 98.7%. In this example, the recovery rates of molybdenum and nickel were 99.4% and 98.1%, respectively.

[0035] Example 8

[0036] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product obtained after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 70% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.0%. In this example, the recovery rates of molybdenum and nickel were 99.4% and 98.6%, respectively.

[0037] Example 9

[0038] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product obtained after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-solid molar ratio of 1:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.3%. In this example, the recovery rates of molybdenum and nickel were 92.6% and 97.1%, respectively.

[0039] Example 10

[0040] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 3:1 was introduced. The reaction was allowed to proceed for 2 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 99.7%. In this example, the recovery rates of molybdenum and nickel were 99.4% and 99.5%, respectively.

[0041] Example 11

[0042] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 1 hour, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 97.8%. In this example, the recovery rates of molybdenum and nickel were 99.4% and 95.7%, respectively.

[0043] Example 12

[0044] Two g of a Mo-Ni / alumina waste catalyst containing 21.71% Mo and 3.558% Ni by mass was calcined in air at 1000°C for 2 hours. After sublimation and condensation, molybdenum trioxide was obtained with a purity of 99.7%. The remaining calcined product after separating the molybdenum trioxide was placed in a reactor and chlorine dioxide gas with a concentration of 60% and a gas-to-solid molar ratio of 2:1 was introduced. The reaction was allowed to proceed for 3 hours, and nickel oxide reacted with chlorine dioxide to obtain nickel chloride with a purity of 98.1%. In this example, the recovery rates of molybdenum and nickel were 99.4% and 97.5%, respectively.

[0045] Comparative Example 1

[0046] Comparative Example 1 differs from Example 3 in that it uses a different type of gas at the same concentration to react with the remaining calcined product. Specifically, the remaining calcined product is placed in a reactor and chlorine gas is introduced to react; the gas concentration is 60%, the gas-to-solid molar ratio is 2:1, and the reaction time is 2 hours. In this method, the recovery rates of molybdenum and nickel are 99.4% and 89.7%, respectively.

[0047] This indicates that the chlorine dioxide gas used in the process of this invention reacts with the remaining roasted products, and the reaction effect using chlorine gas is not as good as the reaction effect using chlorine dioxide.

[0048] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for separating and recovering molybdenum and nickel from spent hydrogenation catalyst, characterized in that, The method steps are as follows: (1) The waste hydrogenation catalyst was placed in a tubular furnace for air roasting, molybdenum was oxidized and sublimated, and molybdenum trioxide was recovered after passing through a condenser. (2) The remaining roasted product obtained in step (1) is placed in a reactor and chlorine dioxide gas is introduced. Nickel oxide reacts with chlorine dioxide at room temperature to obtain nickel chloride product.

2. The method for separating and recovering molybdenum and nickel from spent hydrogenation catalyst according to claim 1, characterized in that, In step (1), the roasting temperature is 800℃-1100℃; the roasting time is 1-3h.

3. The method for separating and recovering molybdenum and nickel from spent hydrogenation catalyst according to claim 1, characterized in that, In step (2), the concentration of chlorine dioxide gas is 50%-70%.

4. The method for separating and recovering molybdenum and nickel from spent hydrogenation catalyst according to claim 1, characterized in that, In step (2), the gas-solid molar ratio of chlorine dioxide gas to the remaining roasting product is 1:1-3:

1.

5. The method for separating and recovering molybdenum and nickel from spent hydrogenation catalyst according to claim 1, characterized in that, In step (2), the reaction time at room temperature is 1-3 hours.

6. The method for separating and recovering molybdenum and nickel from spent hydrogenation catalyst according to claim 1, characterized in that, The recoveries of molybdenum and nickel were 95.3-99.4% and 95.7-99.6%, respectively.

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