WO2022166476A1 - Method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, and application - Google Patents

Abstract

Disclosed are a method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, and an application. The method comprises the following steps: (1) adding sulfuric acid and phosphoric acid into nickel-containing iron powder, and performing heating and stirring to obtain a mixed slurry; (2) adding an oxidant into the mixed slurry, performing heating and stirring, and filtering to obtain iron phosphate and a nickel sulfate solution; (3) washing, filtering, and drying the iron phosphate to obtain an iron phosphate product; and (4) adding a neutralizer into the nickel sulfate solution, performing heating and stirring, and filtering to obtain a nickel sulfate solution subjected to impurity removal. In the present invention, an acid mixture is used to perform acid leaching on the nickel-containing iron powder, and because the acid mixture is added in proportion to the content of iron and nickel in raw materials, nickel can enter the solution in ionic form, and iron is present in a solid phase in an iron phosphate form, so that nickel and iron in the solid phase can be effectively separated. The process is simple, the energy consumption is low, and the cost is also low; meanwhile, the present invention has great economic benefit and is suitable for industrial production and application.

Description

Method and application of extracting nickel from nickel-containing iron powder and preparing iron phosphate technical field

The invention belongs to the technical field of nickel-iron hydrometallurgy, and in particular relates to a method and application for extracting nickel from nickel-containing iron powder and preparing iron phosphate.

Background technique

Nickel ore widely existing in nature is mainly divided into nickel sulfide ore and nickel oxide ore. Due to the high iron content in nickel ore, nickel-iron alloy can be obtained after smelting, which is mainly used to manufacture stainless steel. In recent years, the rapid increase in the production of stainless steel has also stimulated the rapid increase in the global demand for nickel. Nickel is a non-renewable resource. Due to continuous mining and application, nickel resources have been increasingly exhausted. Therefore, the use of secondary nickel in nickel-iron alloys has been adopted. Conversion to primary nickel that can be used in cathode materials is a growing trend.

At present, power battery cathode materials mainly include lithium iron phosphate, ternary materials, lithium manganate, etc. Among them, ternary power batteries are relatively poor in safety performance, but have high energy density, which is one of the development directions of future power batteries. With the technological progress of ternary power batteries, which has led to a decrease in cost and an increase in market recognition, ternary cathode materials accounted for 47.6% of the sales of cathode materials in China in 2019, becoming the cathode material with the highest market share. At the same time, with the continuous improvement and progress of lithium battery technology in recent years, it is gradually found that the battery needs a better metal-nickel, and increasing the nickel content in the ternary material can improve the energy density of the battery, reduce the raw materials and make the lithium battery The battery life has been improved again. Therefore, the ternary cathode material is developing in the direction of high nickelization.

Relatedly disclosed is a wet treatment process of ferronickel material, which involves the process of adding oxidant and strengthening agent to ferronickel powder in a sulfuric acid system for oxidative leaching to obtain a nickel sulfate solution and a solid phase containing iron oxide. This method does not generate hydrogen during the reaction process, which solves some safety problems, but this process requires high-pressure oxygen immersion, and the production cost and equipment maintenance cost are high, which is not suitable for promotion.

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 for extracting nickel from nickel-containing iron powder and preparing iron phosphate, using mixed acid to pickle the nickel-containing iron powder, and adding mixed acid by proportioning with the content of iron and nickel in the raw material, Nickel can enter the solution in the form of ions, and iron exists in the solid phase in the form of iron phosphate, which not only realizes the extraction of nickel from the nickel-containing iron powder, but also prepares nickel and iron into products with higher utilization value. The process is simple, the energy consumption is low, the cost is also low, and at the same time, it has great economic benefits.

A method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, comprising the steps:

(1) adding acid solution to nickel-containing iron powder, heating and stirring to obtain mixed slurry;

(2) adding an oxidant to the mixed slurry, heating and stirring, and filtering to obtain iron phosphate and nickel sulfate solution;

(3) add neutralizer to described nickel sulfate solution and carry out heating and stirring, filter to obtain the nickel sulfate solution after removing impurities;

Wherein, the acid solution is phosphoric acid and sulfuric acid. The sulfuric acid and phosphoric acid are prepared according to the iron content and nickel content in the nickel-containing iron powder.

In some embodiments of the present invention, the concentration of the phosphoric acid is 10-19 mol/L; the liquid-solid ratio of the phosphoric acid to the nickel-containing iron powder is 0.2-5 mL/g.

In some preferred embodiments of the present invention, the concentration of the phosphoric acid is 12-14 mol/L; the liquid-solid ratio of the phosphoric acid to the nickel-containing iron powder is 0.5-3 mL/g.

In some embodiments of the present invention, the concentration of the sulfuric acid is 0.5-10 mol/L; the liquid-solid ratio of the sulfuric acid to the nickel-containing iron powder is 0.5-10 mL/g.

In some preferred embodiments of the present invention, the concentration of the sulfuric acid is 1-5 mol/L; the liquid-solid ratio of the sulfuric acid to the nickel-containing iron powder is 1-8 mL/g.

In some embodiments of the present invention, in step (1), the nickel-containing iron powder is the nickel-iron block obtained by smelting nickel ore (latterite nickel ore and nickel sulfide ore), and the powdery material obtained by the air atomization method , the particle size is 1~900μm, the nickel content in the nickel-containing iron powder is 10~40%, the iron content is 60~85%, and the total impurity content is less than 2%, such as: Co: 0.34%, Mn: 0.09%, Si : 0.27%, Cr: 0.05%, Ca: 0.006%, Mg: 0.004%, Cu: 0.03%, S: 0.21%, P: 0.03%.

In some embodiments of the present invention, in step (1), the heating temperature is 30-100° C., and the stirring time is 1-6 h.

In some preferred embodiments of the present invention, in step (1), the heating temperature is 50-90° C., and the stirring time is 2-5 h.

In some embodiments of the present invention, in step (2), the oxidant is one or more of oxygen, air, hydrogen peroxide, ozone or sodium hypochlorite. Since the iron ions in the leaching solution may be ferrous iron or a mixture of ferrous iron and ferric iron, an oxidizing agent is required to oxidize it to ferric iron.

In some embodiments of the present invention, when the oxidant is oxygen, air, and ozone, the feeding amount is 0.5-2.0 L/min; when the oxidant is hydrogen peroxide or sodium hypochlorite, the amount of the oxidant and the mixed slurry is The volume ratio is (0.05-0.5):1.

In some embodiments of the present invention, in step (2), the heating temperature is 20-100° C., and the stirring time is 1-20 h.

In some preferred embodiments of the present invention, in step (2), the heating temperature is 40-90° C., and the stirring time is 2-15 h.

In some embodiments of the present invention, in step (2), a step of adding a precipitating agent is included before the heating, and the precipitating agent is titanium dioxide, aluminum hydroxide, aluminum oxide, anhydrous iron phosphate or dihydrate phosphoric acid One or more kinds of iron; the solid-liquid ratio of the precipitating agent and the mixed slurry is 1-500 g/L. The precipitation agent can overcome certain energy barriers in the process of iron phosphate precipitation, thereby preparing iron phosphate products.

In some preferred embodiments of the present invention, the solid-to-liquid ratio of the precipitant to the mixed slurry is 10-200 g/L.

In some embodiments of the present invention, in step (2), the iron phosphate is washed, filtered and dried to obtain the iron phosphate after removal of impurities.

In some embodiments of the present invention, in step (2), the washing is pulping washing with water, the liquid-solid ratio of water to iron phosphate is 1-20:1 mL/g, and the washing time is 0.5-5 h.

In some preferred embodiments of the present invention, the liquid-solid ratio of water to iron phosphate is 1-10:1 mL/g, and the washing time is 1-3 hours.

In some embodiments of the present invention, in step (3), the drying temperature is 60-120°C.

In some preferred embodiments of the present invention, in step (3), the drying temperature is 90-110°C.

In some embodiments of the present invention, in step (4), the neutralizing agent is one or more of sodium carbonate, calcium carbonate, ammonium carbonate, potassium hydroxide or sodium hydroxide.

In some embodiments of the present invention, in step (4), the process of adding the neutralizing agent is to prepare the neutralizing agent into a solution or slurry, and add it to the nickel sulfate solution to adjust the pH to 3 ~6.

In some embodiments of the present invention, in step (4), the heating temperature is 30-100° C., and the stirring time is 1-10 h.

In some preferred embodiments of the present invention, in step (4), the heating temperature is 50-80° C., and the stirring time is 2-6 h.

The invention also proposes the application of the method in preparing power battery.

According to a preferred embodiment of the present invention, it has at least the following beneficial effects:

In the invention, the mixed acid is used to pickle the nickel-containing iron powder, and the mixed acid is added in proportion to the content of iron and nickel in the raw material, so that the nickel can enter the solution in the form of ions, and the iron exists in the solid phase in the form of iron phosphate, which can effectively The nickel and iron in the solid phase are separated to obtain nickel sulfate solution and battery-grade iron phosphate products. Nickel sulfate is one of the indispensable materials in ternary materials, and iron phosphate is further used as a precursor of lithium iron phosphate to prepare phosphoric acid. The iron-lithium cathode material not only realizes the extraction of nickel from the nickel-containing iron powder, but also prepares nickel and iron into products with higher utilization value. The method has the advantages of simple process, low energy consumption and low cost. Great economic benefits, suitable for industrial production and application.

Description of drawings

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

1 is a process flow diagram of the present invention for extracting nickel from nickel-containing iron powder and preparing iron phosphate.

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.

Fig. 1 is the process flow diagram that the present invention extracts nickel from nickel-containing iron powder and prepares iron phosphate, as can be seen from the figure, to nickel-containing iron powder, add sulfuric acid and phosphoric acid heating and stirring for a period of time, then add oxidant heating and stirring, filter Ferric phosphate and nickel sulfate solutions can be obtained, a neutralizing agent is added to the nickel sulfate solution, heated and stirred, and impurity precipitates are removed by filtration to obtain a relatively pure nickel sulfate solution. The process is simple, low in energy consumption, and low in cost.

Example 1

A method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, comprising the following steps:

(1) prepare the sulfuric acid of 2mol/L and the phosphoric acid of 14mol/L respectively, standby;

(2) Weighing 50g of nickel-containing iron powder, wherein the iron content is 64.13% and the nickel content is 35.67%, add 37mL of the above phosphoric acid, then add 250mL of the above-mentioned sulfuric acid, and heat the slurry water bath to 80°C, and the stirring time is 3h;

(3) Add 50 mL of hydrogen peroxide, stir for 1 h, then add 7 g of aluminum hydroxide and iron phosphate to the solution, heat to 90 ° C, stir for 10 h, and filter to obtain iron phosphate and nickel sulfate solution;

(4) ferric phosphate was washed with water at a liquid-solid ratio of 5:1 mL/g for 1 h, and after filtration, the ferric phosphate was dried at 105°C to obtain a ferric phosphate product;

(5) Add sodium carbonate solution with a concentration of 25% to the nickel sulfate solution to adjust pH to about 4.5, heat to 80° C., stir for 3 hours, and filter to obtain a nickel sulfate solution with low impurity content.

Example 2

A method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, comprising the following steps:

(1) prepare the sulfuric acid of 1.5mol/L and the phosphoric acid of 13.5mol/L respectively, standby;

(2) Weighing 100g of nickel-containing iron powder, wherein the iron content is 69.28% and the nickel content is 30.29%, 85 mL of the above phosphoric acid is added, and 520 mL of the above sulfuric acid is added, and the slurry water bath is heated to 85 ℃, and the stirring time is 4h;

(3) adding 40mL hydrogen peroxide, feeding 2h aeration oxygen at the same time, adding 15g titanium dioxide and ferric phosphate dihydrate to the solution, heating to 80°C, stirring for 8h, and filtering to obtain ferric phosphate and nickel sulfate solution;

(4) ferric phosphate was washed with water at a liquid-solid ratio of 10:1 mL/g for 2 hours, and after filtration, the ferric phosphate was dried at 90°C to obtain a ferric phosphate product;

(5) Add sodium carbonate solution with a concentration of 15% to the nickel sulfate solution to adjust the pH to about 4.0, heat to 85° C., stir for 2 hours, and filter to obtain a nickel sulfate solution with low impurity content.

Example 3

A method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, comprising the following steps:

(1) respectively prepare the sulfuric acid of 2.5mol/L and the phosphoric acid of 14.5mol/L, standby;

(2) Weighing 100g of nickel-containing iron powder, wherein the iron content is 85.42% and the nickel content is 13.95%, add 95mL of the above phosphoric acid, then add 200mL of the above-mentioned sulfuric acid, heat the slurry water bath to 75°C, and the stirring time is 6h;

(3) Add 100 mL of hydrogen peroxide, stir for 0.5 h, then add 20 g of alumina and titanium dioxide to the solution, heat up to 85°C, stir for 6 h, and filter to obtain iron phosphate and nickel sulfate solution;

(4) ferric phosphate was washed with water at a liquid-solid ratio of 8:1 mL/g for 0.5 h, and after filtration, the ferric phosphate was dried at 105°C to obtain a ferric phosphate product;

(5) Add sodium hydroxide solution with a concentration of 5% to the nickel sulfate solution to adjust pH to about 5.0, heat to 70° C., stir for 4 hours, and filter to obtain a nickel sulfate solution with low impurity content.

Example 4

A method for extracting nickel from nickel-containing iron powder and preparing iron phosphate, comprising the following steps:

(1) prepare the sulfuric acid of 3.0mol/L and the phosphoric acid of 14mol/L respectively, standby;

(2) Weigh 100g of nickel-containing iron powder, wherein the iron content is 83.29% and the nickel content is 15.99%, add 110 mL of the above phosphoric acid, and then add 170 mL of the above-mentioned sulfuric acid, and heat the slurry water bath to 80 ° C, and the stirring time is 5h;

(3) Add 65mL of sodium hypochlorite, stir for 2h, then add 20g of aluminum hydroxide and ferric phosphate dihydrate to the solution, heat to 90°C, stir for 8h, and filter to obtain ferric phosphate and nickel sulfate solution;

(4) ferric phosphate was washed with water for 1 h at a liquid-solid ratio of 12:1 mL/g, and after filtration, the ferric phosphate was dried at 100° C. to obtain a ferric phosphate product;

(5) adding calcium carbonate solution to the nickel sulfate solution to adjust the pH to about 5.5, heating to 75° C., stirring for 4 hours, and filtering to obtain a nickel sulfate solution with a lower impurity content.

Test example

Get the ferric phosphate finished product that above-mentioned embodiment 1～3 makes and carry out physical and chemical index detection, the result is as shown in table 1 below:

Table 1 Physicochemical index detection results of iron phosphate prepared by Example 1-3 of the present invention

As can be seen from Table 1, each physical and chemical index of the iron phosphate obtained by the preparation method of the present invention meets the standard of the lithium iron phosphate positive electrode material.

Get the nickel sulfate solution that above-mentioned embodiment 1～3 makes and carry out impurity content analysis, the result is as shown in following table 2:

Table 2 Analysis (mg/L) of impurities in nickel sulfate solution prepared in Examples 1 to 3 of the present invention

	Ni	Fe	Co	Mn	Cu	Al
Example 1	35891.5	1.07	343.2	53.9	0.139	0.229
Example 2	28455.8	2.73	456.6	87.2	0.189	0.357
Example 3	10652.6	10.72	212.6	67.9	0.155	0.582
	Ca	Mg	P	Cr	Zn	Si
Example 1	16.7	1.56	1.75	0.138	1.142	73.9
Example 2	13.9	0.98	2.15	0.112	0.997	57.2
Example 3	20.5	1.12	2.67	0.145	1.102	65.8

As can be seen from Table 2, the impurity content of the nickel sulfate solution obtained by the preparation method of the present invention is relatively low, and the impurity (excluding Co, Mn) content in the nickel sulfate solution after impurity removal is less than 100 μm.

Get the iron phosphate that the above-mentioned embodiment 1～3 obtains and prepare into lithium iron phosphate according to the conventional method, the electrical property of the obtained lithium iron phosphate is detected, the result is as shown in Table 3:

Table 3 The iron phosphate synthesis lithium iron phosphate powder of the embodiment 1-3 of table 3 compares table of compaction density and electrical property test result

As can be seen from Table 3, the compacted density and electrical properties of the lithium iron phosphate powder synthesized by the iron phosphate obtained in the present invention have all reached the use standard of iron phosphate for lithium iron phosphate, and can be directly used as the precursor produced by lithium iron phosphate.

Using the method of the embodiment of the present invention to extract the nickel in the nickel-containing iron powder can effectively separate the nickel and the iron, and simultaneously obtain two products with greater economic benefits. In the present invention, when the mixed acid of sulfuric acid and phosphoric acid is used to dissolve the nickel-containing iron powder, the reaction is mainly based on the reaction of iron and phosphoric acid to obtain ferrous dihydrogen phosphate, nickel and sulfuric acid to obtain nickel sulfate, and then the oxidizing agent is used to dissolve the ferrous phosphate. At the same time, iron phosphate is obtained under the action of the precipitating agent, and the trace impurities in the nickel sulfate solution can be discharged as slag after the impurity removal by the neutralizing agent, thereby preparing a nickel sulfate solution with a lower impurity content, The reagents used in this method are all readily available, the operation is simple, the Fe/P of the prepared iron phosphate product is between 0.96 and 1, and the content of impurities (excluding Co and Mn) in the nickel sulfate solution after impurity removal is less than 100 pm.

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 extracting nickel from nickel-containing iron powder and preparing iron phosphate, comprising the steps of:

   (1) adding acid solution to nickel-containing iron powder, heating and stirring to obtain mixed slurry;

   (2) adding an oxidant to the mixed slurry, heating and stirring, and filtering to obtain iron phosphate and nickel sulfate solution;

   (3) add neutralizer to described nickel sulfate solution and carry out heating and stirring, filter to obtain the nickel sulfate solution after removing impurities;

   Wherein, the acid solution is phosphoric acid and sulfuric acid.
2. The method according to claim 1, wherein the concentration of the phosphoric acid is 10-19 mol/L; the liquid-solid ratio of the phosphoric acid to the nickel-containing iron powder is 0.2-5 mL/g.
3. The method according to claim 1, wherein the concentration of the sulfuric acid is 0.5-10 mol/L; the liquid-solid ratio of the sulfuric acid to the nickel-containing iron powder is 0.5-10 mL/g.
4. The method according to claim 1, characterized in that, in step (1), the nickel-containing iron powder is a nickel-iron nugget obtained by smelting nickel ore, and the powdery material obtained by an air atomization method has a particle size of 1- 900 μm, the content of nickel in the nickel-containing iron powder is 10-40%, and the content of iron is 60-85%.
5. The method according to claim 1, characterized in that, in step (1), the heating temperature is 30-100° C., and the stirring time is 1-6 h.
6. The method according to claim 1, wherein in step (2), the oxidant is one or more of oxygen, air, hydrogen peroxide, ozone or sodium hypochlorite; in step (2), the heated The temperature is 20～100°C, and the stirring time is 1～20h.
7. The method according to claim 1, characterized in that, in step (2), the iron phosphate is washed, filtered and dried to obtain the iron phosphate after removal of impurities.
8. The method according to claim 1, characterized in that, in step (2), before the heating, it further comprises the step of adding a precipitating agent, and the precipitating agent is titanium dioxide, aluminum hydroxide, aluminum oxide, anhydrous iron phosphate Or one or more of ferric phosphate dihydrate; the solid-liquid ratio of the precipitant to the mixed slurry is 1-500 g/L.
9. The method according to claim 1, wherein, in step (3), the neutralizing agent is one or more of sodium carbonate, calcium carbonate, ammonium carbonate, potassium hydroxide or sodium hydroxide; step In (3), the heating temperature is 30-100° C., and the stirring time is 1-10 h.
10. Application of the method of any one of claims 1-9 in preparing power batteries.

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