WO2022213679A1 - Method for leaching nickel-ammonia solution from nickel-iron alloy in wet process and application - Google Patents

Abstract

The present invention relates to the field of metallurgy. Disclosed are a method for leaching a nickel-ammonia solution from a nickel-iron alloy in a wet process and an application. The method comprises the following steps: performing oxidizing roasting on a crude nickel-iron alloy, and then performing spray granulation to obtain iron nickel oxide powder; adding the iron nickel oxide powder into an alkali solution, heating, performing ammonia leaching reaction, and filtering to obtain iron slag and a leachate; and extracting the leachate, and removing oil from a raffinate, thereby obtaining a nickel-ammonia solution. According to the present invention, nickel and iron are oxidized and roasted, and then spray granulation and atmospheric-pressure ammonia leaching are performed, such that high-pressure leaching energy consumption is saved; in addition, the obtained nickel-ammonia solution is directly used for ternary precursor synthesis, such that an ammonium source that should have been introduced in a synthesis process is saved.

Description

A kind of method and application of nickel-iron alloy wet leaching nickel-ammonia solution technical field

The invention belongs to the field of metallurgy, and in particular relates to a method and application of a nickel-iron alloy wet leaching nickel-ammonia solution.

Background technique

With the rise of the new energy industry, especially the popularity of high-nickel batteries, the demand for nickel is gradually increasing. Nickel is an important strategic metal and is widely used in key materials such as stainless steel, superalloys, fuel cells and high-tech In the field, the current sources of nickel resources are mainly two kinds of nickel sulfide ore and nickel oxide ore (ie laterite nickel ore) in crustal resources, of which 30% are nickel sulfide ore and 70% are laterite nickel ore. And with the rapid development of the stainless steel industry, the production of nickel is in short supply, and the high-quality nickel sulfide ore is gradually being mined, which makes the mining and application of laterite nickel ore become more and more extensive.

Laterite nickel ore has become the main raw material for the production of ferronickel products. The process principles of processing different ores can be summarized as: (1) fire process; (2) wet ammonia leaching process; (3) wet pressure acid leaching process. The fire process requires a higher nickel grade, and for laterite nickel ore with a nickel content of about 1%, the wet ammonia leaching process can be used. The problems of higher requirements, high consumption of auxiliary materials, serious scarring of the pressurizing valve, and high operating and production costs directly restrict the development of the enterprise. However, the wet ammonia leaching process has weak corrosive materials, weak equipment material requirements, easy processing and production, and adopts atmospheric pressure leaching, the equipment structure is simple, and the reagents can be recycled.

In the current ammonia leaching process, if laterite ore is used directly as raw material, the nickel metal recovery rate is generally about 80%. If nickel-iron alloy powder is used with conventional ammonium carbonate and ammonium bicarbonate systems, the leaching rate is generally about 90%. The purity of the obtained iron concentrate is less than 80%, and an additional ammonium source is required to leaching the iron ore.

SUMMARY OF THE INVENTION

The present invention aims to solve at least one of the technical problems existing in the above-mentioned prior art. To this end, the present invention proposes a method and application of a nickel-iron alloy wet leaching of nickel-ammonia solution, the method can realize the separation of nickel and iron in nickel-iron, and the recovery rate of nickel is greater than 93.2%, and the recovery rate of iron is greater than 99.2%, Nickel is used directly for precursor synthesis and iron is sold directly as iron source.

To achieve the above object, the present invention adopts the following technical solutions:

A method for nickel-iron alloy wet leaching of nickel-ammonia solution, comprising the following steps:

(1) oxidative roasting of crude nickel-iron alloy is carried out, and then spray granulation is carried out to obtain nickel-iron oxide powder;

(2) adding described nickel oxide iron powder to alkaline solution, heating, carrying out ammonia leaching reaction, filtering to obtain iron slag and leachate;

(3) extracting the leaching solution, extracting the raffinate for degreasing, to obtain the nickel ammonia solution.

Preferably, in step (1), the crude nickel-iron alloy is obtained by reducing and roasting laterite nickel ore, and the content of nickel in the crude nickel-iron alloy is 15%-40%, and the content of iron is 60%-85%. %, the content of copper is 1-1.5%, the content of sulfur is 0.01-0.2%, and the content of cobalt is 0.5-0.8%.

Preferably, in step (1), the temperature of the oxidative roasting is 1200° C.˜1500° C., and the time of the oxidative roasting is 0.5˜5 h.

Preferably, in step (1), the oxygen source of the oxidative roasting is oxygen or air. More preferably, the air is dehydrated air.

Preferably, in step (1), the particle size of the nickel-iron oxide powder is less than 60 mesh.

Preferably, in step (2), the lye solution is obtained by mixing ammonium salt and ammonia water; the ammonium salt is at least one of ammonium sulfate, ammonium hydrogen sulfate, and ammonium carbonate.

More preferably, the dosage of NH ₄ ⁺ is 1.0-3.0 times of the theoretical dosage.

Preferably, in step (2), the liquid-solid ratio of the alkali solution and the nickel-iron oxide powder is (2-4): 1 mL/g.

Preferably, in step (2), the stirring speed is 400r/min～800r/min.

Preferably, in step (2), the heating temperature is 60°C to 90°C.

Preferably, in step (2), the time of the ammonia immersion reaction is 3-6 hours.

Preferably, in step (2), the pH of the slurry is also detected to be 10-12 before the filtration.

Preferably, in step (2), the iron slag is a mixture of magnetite and hematite.

Preferably, in step (2), a process of washing the iron slag is also included; the liquid-solid ratio of the solvent used in the washing and the iron slag is (2-4): 1 mL/g.

More preferably, the number of times of the washing is 3 to 5 times.

Preferably, in step (3), the extractant used in the extraction is P507.

Preferably, in step (3), the degreasing substance used in the degreasing is activated carbon.

Preferably, in step (3), it also includes synthesizing the nickel-ammonia solution, that is, by evaporating ammonia to the solution, to obtain a ternary battery positive electrode material precursor and ammonium-containing wastewater.

More preferably, the alkaline buffer solution is added to the ammonium-containing waste water to adjust the pH to be alkaline, and then the ammonia is evaporated by heating, and the ammonia water obtained after cooling is reused for ammonia leaching.

More preferably, the alkaline buffer is at least one of sodium hydroxide, potassium hydroxide or sodium carbonate; the concentration of the alkaline buffer is 1-5 mol/L.

More preferably, the pH adjustment to alkaline is to adjust the pH to 10-12.

Reaction principle of the present invention:

2NiO+8NH ₃ +2(NH ₄ ) ₂ SO ₄ →2[Ni(NH ₃ ) ₆ ]SO ₄ +2H ₂ O;

2CoO+8NH ₃ +2(NH ₄ ) ₂ SO ₄ →2[Ni(NH ₃ ) ₆ ]SO ₄ +2H ₂ O;

_2CuO +8NH3+ ₂ ( _NH4 ) _2SO4 →2[Cu( _NH3 ) ₆ ] _{SO4 +} 2H2O.

The present invention also provides the application of the above method in preparing the positive electrode material of the ternary battery.

With respect to the prior art, the beneficial effects of the present invention are as follows:

1. the present invention first oxidizes and roasts ferronickel, sprays granulation again, and impregnates ammonia at atmospheric pressure, thus reducing the energy consumption of high-pressure leaching, and the nickel-ammonia solution obtained simultaneously is directly used for the synthesis of ternary precursors, which reduces the amount of time in the synthesis process. A source of ammonium needs to be introduced.

2. The nickel-ammonia solution obtained by the present invention is directly used for the synthesis of precursors, and the iron oxide with a purity of more than 93% can be directly sold as an iron source for iron and steel plants. The invention has the advantages of short technological process, easy control of technical conditions and simple operation, and the nickel in the nickel-iron alloy can be made into the original solution for synthesizing the ternary precursor in one process.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments, wherein:

FIG. 1 is a process flow diagram of Embodiment 1 of the present invention.

Detailed ways

The concept of the present invention and the technical effects produced will be clearly and completely described below with reference to the embodiments, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts are all within the scope of The scope of protection of the present invention.

Example 1

The method for nickel-iron alloy wet leaching of nickel-ammonia solution of the present embodiment comprises the following steps:

(1) Crude nickel-iron alloy (from a laterite nickel ore processing plant in Indonesia) (the composition of the crude nickel-iron alloy is: Fe 70%, Ni 28%, Cu 0.5%, S 0.1%, Co 0.6%) 100g Under the condition of introducing oxygen, oxidative roasting is carried out, and the roasting temperature is 1300 ° C, and the roasted molten slurry is sprayed and granulated, and sieved to obtain nickel-iron oxide powder with a particle size of less than 100 mesh (>95%);

(2) In a closed container, add a mixed solution of ammonia water and ammonium sulfate according to 1.5 times the theoretical amount of ammonium consumption required for nickel, cobalt and copper in the nickel-iron oxide powder, and at a liquid-solid ratio of 2:1, and put it into a 70° C. In the water bath, it was added at a constant temperature of 400 r/min, and the overflowed ammonia gas was pumped through the airflow pump and then pumped into the reacted slurry to realize the recycling of ammonia. The total reaction time was controlled at 4h, and the pH of the slurry was detected after the reaction. = 10.0, and filtered while hot to obtain iron slag and leaching solution. The iron slag was washed 3 times at a liquid-solid ratio of 2:1 ml/g to obtain iron ore. The measured iron ore contained 0.15% nickel and 93.6% iron. It can be sold directly as a product, and the leaching rates of nickel and cobalt in this process are 98.2% and 94.1% respectively;

(3) The leaching solution is extracted to remove copper, and the copper concentration in the raffinate is controlled to be less than 5ppm, and then the raffinate is deoiled, and the oil in the liquid after deoiling is controlled to be less than 0.5ppm, that is, the nickel ammonia solution is directly used as a precursor. Synthesis, can obtain the precursor that meets the requirements, the synthetic wastewater is added with liquid caustic soda, the pH of the wastewater is adjusted to 11, and the ammonia is distilled, and the recovered ammonia water can be recycled.

Table 1: Content of each element in the iron ore of Example 1

	Fe	Ni	Co	S	Cu
content/%	93.6	0.15	0.09	0.01	0.05
Recovery rate/%	99.99	\	\	\	\

Table 1 shows the content of each element in the iron concentrate of Example 1. From Table 1, the recovery rate of iron in the crude nickel-iron alloy is 99.99%, and the iron content is 93.6%, which can be directly sold as a product.

Table 2: Concentrations of Elements in Nickel-Ammonia Solution

	Ni	Fe	Co	Cu
Concentrationg/L	137.48	0.001	2.82	0.003
Leach rate/%	98.2	0	94.1	0

Table 2 is the concentration of each element in the nickel-ammonia solution of Example 1. It can be obtained from Table 2. The leaching rate of nickel in the crude nickel-iron alloy is 98.2%, the leaching rate of cobalt is 94.1%, and the rest of the impurities are free. Example 2 The nickel ammonia solution can be used for the preparation of ternary precursors.

Fig. 1 is the process flow diagram of embodiment 1, as can be seen from the figure, through the process of high temperature oxidation-spray granulation-atmospheric leaching-extraction copper removal-synthesis precursor, the crude nickel-iron alloy is subjected to wet leaching to obtain The nickel-ammonia solution is directly used for precursor synthesis, and iron oxide is directly sold as an iron source for iron and steel plants.

Example 2

The method for nickel-iron alloy wet leaching of nickel-ammonia solution of the present embodiment comprises the following steps:

(1) Crude nickel-iron alloy (from a laterite nickel ore processing plant in Indonesia) (the composition of the crude nickel-iron alloy is: Fe 70%, Ni 28%, Cu 0.5%, S 0.1%, Co 0.6%) 100g Under the condition of introducing oxygen, oxidative roasting is carried out, and the roasting temperature is 1350 ° C, and the roasted molten slurry is sprayed and granulated, and sieved to obtain nickel-iron oxide powder with a particle size of less than 100 mesh (>95%);

(2) In a closed container, add a mixed solution of ammonia water and ammonium sulfate according to 2.0 times the theoretical amount of ammonium consumption required by nickel-cobalt-copper in the nickel-iron oxide powder, and at a liquid-solid ratio of 3:1, and put it into a 80° C. In the water bath, the constant temperature was added at a rotating speed of 600r/min, and the overflowed ammonia gas was pumped through the airflow pump and then pumped into the reacted slurry to realize the recycling of ammonia. The total reaction time was controlled at 5h, and the pH of the slurry was detected after the reaction. = 10.5, and filtered while hot to obtain iron slag and leachate. The iron slag was washed 3 times at a liquid-solid ratio of 3:1 ml/g to obtain iron ore. The measured iron ore contained 0.12% nickel and 94.2% iron. It can be sold directly as a product, and the leaching rates of nickel and cobalt in this process are 97.7% and 96.3% respectively;

(3) The leaching solution is extracted to remove copper, and the copper concentration in the raffinate is controlled to be less than 5 ppm, and then the raffinate is deoiled, and the oil in the liquid after degreasing is controlled to be less than 0.5 ppm, that is, the nickel ammonia solution is directly used as a precursor. Synthesis, can obtain the precursor that meets the requirements, the synthetic wastewater is added with sodium carbonate, the pH of the wastewater is adjusted to 11.5, and the ammonia is distilled, and the recovered ammonia water can be recycled.

Table 3: Content of each element in iron slag

	Fe	Ni	Co	S	Cu
content/%	94.2	0.12	0.05	0.02	0.03
Recovery rate/%	99.99	\	\	\	\

Table 3 shows the content of each element in the iron concentrate of Example 2. From Table 3, the recovery rate of iron in the crude nickel-iron alloy is 99.99%, and the iron content is 94.2%, which can be directly sold as a product.

Table 4: Content of each element in nickel-ammonia solution

	Ni	Fe	Co	Cu
Concentrationg/L	89.04	0.001	1.93	0.002
Leach rate/%	95.4	0	96.3	0

Table 4 shows the content of each element in the bottom liquid used for the synthesis of the ternary precursor in Example 2. It can be obtained from Table 4 that the leaching rate of nickel in the crude nickel-iron alloy is 95.4%, the leaching rate of cobalt is 96.3%, and the other The impurity removal rates of impurities are all greater than 99.9%, and the nickel sulfate hexahydrate of Example 2 can be used for the preparation of ternary precursors.

Example 3

The method for nickel-iron alloy wet leaching of nickel-ammonia solution of the present embodiment comprises the following steps:

(1) Crude nickel-iron alloy (from a laterite nickel ore processing plant in Indonesia) (the composition of the crude nickel-iron alloy is: Fe 70%, Ni 28%, Cu 0.5%, S 0.1%, Co 0.6%) 100g Under the condition of introducing oxygen, oxidative roasting is carried out, and the roasting temperature is 1350 ° C, and the roasted molten slurry is sprayed and granulated, and sieved to obtain nickel-iron oxide powder with a particle size of less than 100 mesh (>95%);

(2) In a closed container, add a mixed solution of ammonia water and ammonium sulfate according to 2.0 times the theoretical amount of ammonium consumption required by nickel-cobalt-copper in the nickel-iron oxide powder, according to the liquid-solid ratio of 4:1, and put it into a 60° C. In the water bath, it was added at a constant temperature of 700 r/min, and the overflowed ammonia gas was pumped through the airflow pump and then pumped into the reacted slurry to realize the recycling of ammonia. The total reaction time was controlled at 6h, and the pH of the slurry was detected after the reaction. = 11.5, and filtered while hot to obtain iron slag and leachate. The iron slag was washed twice with a liquid-solid ratio of 4:1 ml/g. The measured iron ore contained 0.12% nickel and 94.9% iron, which can be directly used as a product. For sale, the leaching rates of nickel and cobalt in this process are 93.7% and 95.2% respectively;

(3) The leaching solution is extracted to remove copper, and the copper concentration in the raffinate is controlled to be less than 5ppm, and then the raffinate is deoiled, and the oil in the liquid after deoiling is controlled to be less than 0.5ppm, that is, the nickel ammonia solution is directly used as a precursor. Synthesis can obtain a precursor that meets the requirements. After the synthesis, potassium hydroxide is added to the wastewater, the pH of the wastewater is adjusted to 12, and ammonia is distilled, and the recovered ammonia water can be recycled.

Table 5: Content of each element in iron slag

	Fe	Ni	Co	S	Cu
content/%	94.9	0.11	0.06	0.02	0.01
Recovery rate/%	99.99	\	\	\	\

Table 5 shows the content of each element in the iron concentrate of Example 3. From Table 5, the recovery rate of iron in the crude nickel-iron alloy is 99.99%, and the iron content is 94.9%, which can be directly sold as a product.

Table 6: Content of each element in nickel-ammonia solution

	Ni	Fe	Co	Cu
Concentration/g/L	65.59	0.002	1.43	0.003
Leach rate/%	93.7	0	95.2	0

Table 6 is the content of each element in the nickel-ammonia solution of Example 3. It can be obtained from Table 6. The leaching rate of nickel in the crude nickel-iron alloy is 93.7%, the leaching rate of cobalt is 95.2%, and there are no other impurities. The nickel-ammonia solution It can be used for the preparation of ternary precursors. Comparative Example 1 (Compared with Example 1, no oxidative granulation was performed)

The method for wet leaching nickel-ammonia solution of nickel-iron alloy of the present comparative example comprises the following steps:

(1) Crude nickel-iron alloy (from a laterite nickel ore processing plant in Indonesia) (the composition of the crude nickel-iron alloy is: Fe 70%, Ni 28%, Cu 0.5%, S 0.1%, Co 0.6%) 100g Crushing and sieving to obtain nickel-iron alloy powder with particle size less than 100 mesh (>95%);

(2) In a closed container, add a mixed solution of ammonia water and ammonium sulfate according to 1.5 times the theoretical amount of ammonium consumption required for nickel-cobalt-copper in the nickel-iron alloy powder, and the liquid-solid ratio is 2:1, and put it into a water bath at 70 ° C. In the pot, it was added at a constant temperature of 400r/min, and the overflowed ammonia gas was pumped into the reacted slurry through the airflow pump to realize the recycling of ammonia. The total reaction time was controlled at 4h, and the pH of the slurry was detected after the reaction. 10.0, and filtered while hot to obtain iron slag and leachate, and the iron slag was washed 3 times at a liquid-solid ratio of 2:1 ml/g to obtain iron ore;

(3) the leaching solution is extracted to remove copper, and the copper concentration in the raffinate is controlled to be less than 5ppm, then the raffinate is deoiled, and the oil in the liquid after the degreasing is controlled to be less than 0.5ppm to obtain a nickel-ammonia solution, and the synthetic wastewater Add liquid caustic soda, adjust the pH of wastewater to 11, and steam ammonia, and the recovered ammonia water can be recycled.

Table 7: Content of each element in the iron ore of Comparative Example 1

	Fe	Ni	Co	S	Cu
content/%	92.2	5.6	0.34	0.02	0.21
Recovery rate/%	99.99	\	\	\	\

Table 7 shows the content of each element in the iron ore of Comparative Example 1. It can be obtained from Table 5 that the recovery rate of iron in the crude nickel-iron alloy is 99.99%, and the iron content is 92.2%.

Table 8: Content of each element in the nickel-ammonia solution of Comparative Example 1

	Ni	Co	S	Fe	Cu
Concentration/g/L	87.48	0.98	0.53	0.001	0.002
Leach rate/%	62.49	32.7	\	0	0

Table 8 shows the content of each element in the nickel-ammonia solution of Comparative Example 1. From Table 8, the leaching rate of nickel in the crude nickel-iron alloy is 62.49%, which cannot be directly used for precursor synthesis.

According to the data of Comparative Example 1, the effect is poor, because there is no oxidative roasting, nickel and iron in the nickel-iron alloy are both simple substances, and iron and ammonia water will not react, but the obtained iron slag still contains high content of iron slag. Ni; at the same time, the reaction degree of nickel and ammonia water is also weak, and the leaching rate of nickel needs to be improved by pressurized oxidation leaching, so the leaching rate of nickel in the obtained nickel-ammonia solution is low.

The embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned embodiments, and within the scope of knowledge possessed by those of ordinary skill in the art, various Variety. Furthermore, the embodiments of the present invention and features in the embodiments may be combined with each other without conflict.

Claims (10)

1. A method for nickel-iron alloy wet leaching of nickel-ammonia solution, comprising the following steps:

   (1) oxidative roasting is carried out with crude nickel-iron alloy, and then spray granulation is carried out to obtain nickel-iron oxide powder;

   (2) adding described nickel oxide iron powder to alkaline solution, heating, carrying out ammonia leaching reaction, filtering to obtain iron slag and leachate;

   (3) extracting the leaching solution, extracting the raffinate for degreasing, to obtain the nickel ammonia solution.
2. The method according to claim 1, wherein in step (1), the crude nickel-iron alloy is obtained by reducing laterite nickel ore, and the content of nickel in the crude nickel-iron alloy is 15%-40%. %, the content of iron is 60%-85%, the content of copper is 1-1.5%, the content of sulfur is 0.01-0.2%, and the content of cobalt is 0.5-0.8%.
3. The method according to claim 1, wherein in step (1), the temperature of the oxidative roasting is 1200°C to 1500°C, and the time of the oxidative roasting is 0.5 to 5 h.
4. The method according to claim 1, wherein in step (1), the oxygen source of the oxidative roasting is oxygen or air.
5. The method according to claim 1, wherein, in step (2), the lye is obtained by mixing ammonium salt and ammonia water; the ammonium salt is at least one of ammonium sulfate, ammonium hydrogen sulfate or ammonium carbonate kind.
6. The method according to claim 1, characterized in that, in step (2), the heating temperature is 60°C to 90°C; in step (2), the time of the ammonia immersion reaction is 3 to 6h; step In (2), the pH of the slurry is also detected to be 10-12 before the filtration.
7. The method according to claim 1, characterized in that, in step (2), further comprising a process of washing the iron slag; the liquid-solid ratio of the solvent used in the washing and the iron slag is (2- 4): 1 mL/g.
8. The method according to claim 1, wherein in step (3), the extractant used in the extraction is P507; in step (3), the degreasing substance used in the degreasing is activated carbon.
9. The method according to claim 1, characterized in that, in step (3), it further comprises synthesizing a nickel-ammonia solution, that is, by evaporating ammonia from the solution, to obtain a ternary battery positive electrode material precursor and ammonium-containing wastewater.
10. Application of the method according to any one of claims 1 to 9 in preparing a positive electrode material for a ternary battery.

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