CN102909383B - The preparation method of extra-fine nickel powder or cobalt powder - Google Patents

Abstract

The invention is applicable to the field of metal particle preparation, and provides a preparation method of ultrafine nickel powder or cobalt powder, including ball milling; first airflow crushing and classification treatment; reduction treatment and second airflow crushing and classification treatment. The preparation method of ultrafine nickel powder or cobalt powder of the present invention uses ball milling and airflow crushing in combination, so that the hard aggregates and soft aggregates in the nickel powder precursor or cobalt powder precursor are broken and dispersed, effectively It prevents the re-agglomeration of the nickel powder precursor or cobalt powder precursor after ball milling; after the reduction treatment, the airflow crushing is carried out again, so that the agglomerates in the nickel powder or cobalt powder are broken and dispersed again, effectively preventing the re-agglomeration after the reduction treatment. The agglomeration of nickel powder or cobalt powder realizes the uniform particle size of ultrafine nickel powder or cobalt powder. The preparation method of the invention has simple operation and low cost, and is very suitable for industrial production.

Description

The preparation method of superfine nickel powder or cobalt powder

technical field

The invention belongs to the technical field of metal particle preparation, and in particular relates to a preparation method of ultrafine nickel powder or cobalt powder.

Background technique

At present, cobalt carbonate or cobalt oxalate is used as raw material to prepare ultrafine cobalt powder, adding a certain proportion of dispersant, vacuum ball milling under argon protection environment, and reduction in hydrogen atmosphere, but this method requires a ball mill tank Vacuuming and argon protection are required, and the ball milling time is long, so the production cost is high; at the same time, the particle size of the prepared nickel powder or cobalt powder is different and uneven, which cannot meet the needs of production.

Contents of the invention

In view of this, the embodiment of the present invention provides a method for preparing ultrafine nickel powder or cobalt powder, which solves the technical problems of high cost of preparing ultrafine nickel powder or cobalt powder and uneven particle size of nickel powder or cobalt powder in the prior art .

The present invention is achieved like this,

A preparation method of superfine nickel powder or cobalt powder, comprising the steps of:

Ball mill the nickel powder precursor or cobalt powder precursor for 3-20 hours;

The ball-milled nickel powder precursor or cobalt powder precursor is subjected to airflow crushing and grading treatment, and the nickel powder precursor or cobalt powder precursor of the target particle size is collected through crushing and grading impeller frequency;

Roasting the nickel powder precursor or cobalt powder precursor in a reducing atmosphere at a temperature of 300-450°C to obtain nickel powder or cobalt powder;

The nickel powder or cobalt powder is subjected to airflow crushing and classification treatment, and the ultrafine nickel powder or cobalt powder is obtained by crushing and classifying the frequency of the impeller.

The preparation method of ultra-fine nickel powder or cobalt powder in the embodiment of the present invention uses ball milling and airflow crushing in combination, so that both hard aggregates and soft aggregates in the nickel powder precursor or cobalt powder precursor are broken and dispersed, Effectively prevent the re-agglomeration of the nickel powder precursor or cobalt powder precursor after ball milling; after the reduction treatment, the air-flow crushing is performed again, so that the soft aggregates in the nickel powder or cobalt powder can be broken and dispersed again, effectively preventing the reduction The agglomeration of the treated nickel powder or cobalt powder realizes the uniform particle size of the superfine nickel powder or cobalt powder. The preparation method of the embodiment of the present invention has simple operation and low cost, and is very suitable for industrial production.

Description of drawings

Fig. 1 is the flow chart of the preparation method of superfine nickel powder or cobalt powder of the embodiment of the present invention;

Fig. 2 is the flow chart of the preparation method of the embodiment of the present invention one superfine nickel powder or cobalt powder;

Fig. 3 is an electron microscope scanning photo of the ultrafine cobalt powder prepared in Example 3 of the present invention.

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Please refer to Fig. 1, Fig. 1 shows the flow chart of the preparation method of a kind of superfine nickel powder or cobalt powder of the embodiment of the present invention, comprises the steps:

Step S01, ball milling

Ball mill the nickel powder precursor or cobalt powder precursor for 3-20 hours;

Step S02, the first air flow crushing and grading treatment

Perform air crushing and classification treatment on the nickel powder precursor or cobalt powder precursor after ball milling, and collect the nickel powder precursor or cobalt powder precursor;

Step S03, restore

Roasting the nickel powder precursor or cobalt powder precursor in a reducing atmosphere at a temperature of 300-450°C to obtain nickel powder or cobalt powder;

Step S04, the second air flow crushing and grading treatment

The nickel powder or cobalt powder is subjected to airflow crushing and classification treatment, and the nickel powder or cobalt powder is collected to obtain superfine nickel powder or cobalt powder.

Specifically, the nickel powder precursor is selected from one or more of nickel carbonate, nickel oxalate, nickel oxide, nickelous oxide or nickel hydroxide; the cobalt powder precursor is selected from cobalt carbonate, cobalt oxalate, cobalt oxide, oxide One or more of sub-cobalt or cobalt hydroxide.

Specifically, in step S01, the equipment used for the ball milling is not limited, for example, a planetary power ball mill, a high-energy stirring ball mill, etc.; the ball milling time is 3-20 hours, preferably 10-20 hours; in the ball milling step, the speed of the ball milling equipment 100-300 rpm. Through ball milling, the nickel powder precursor or cobalt powder precursor is crushed and dispersed, especially for some hard aggregates in the nickel-cobalt powder precursor, which plays a particularly effective role in crushing and dispersing.

Specifically, in step S02, the airflow crushing and grading process refers to crushing and screening by an ultrasonic airflow crushing and classifying machine to obtain powder with a target particle size. The equipment used in the airflow crushing and grading treatment in this step is a fluidized bed airflow mill. The fluidized bed airflow mill is a kind of equipment that uses high-speed airflow to realize ultrafine crushing of dry materials. It consists of a crushing nozzle and a grading rotor. , screw feeder, etc., the material enters the crushing chamber through the screw feeder, and the pressure-velocity air is sprayed into the crushing chamber at high speed through a specially configured supersonic nozzle. The material accelerates in the supersonic nozzle jet, and repeatedly impacts and collides at the nozzle intersection. , to achieve crushing. The crushed material enters the classification chamber with the updraft. Since the classifier rotates at high speed, the particles are subjected to both the centrifugal force generated by the classifying rotor and the centripetal force generated by the viscosity of the air flow. The chamber continues to impact and crush, and the fine particles below the classification diameter enter the cyclone separator and collector with the airflow to collect, and the gas is discharged by the induced draft fan. In the air flow crushing step, the frequency of the ultrasonic air flow crushing classifier is 30-70HZ/min; the atmosphere of the air flow crushing is not limited, such as air, inert atmosphere (such as nitrogen atmosphere, argon atmosphere, etc.), reducing atmosphere (hydrogen atmosphere, carbon monoxide atmosphere, etc.), etc. Since the ball milling process in step S01 will generate a large amount of heat, the moisture in the nickel powder precursor or cobalt powder precursor will evaporate to form water vapor. At the same time, due to the powder refinement in the ball milling process, the surface energy will increase, and the powder will easily form agglomeration again. body, after the air flow crushing treatment in step S02, the agglomerates can be effectively dispersed, so that the nickel powder precursor or cobalt powder precursor is effectively broken; the nickel powder precursor or cobalt powder precursor obtained in this step S02 The particle size is above 200 mesh.

In this step S02, the ultrasonic airflow crushing and classifying machine controls the crushing and grading effect through the crushing frequency. When the particle size of the powder reaches the requirement, it is separated, and the particle size is not reached. Return to the crushing chamber to continue crushing, collect the target powder, and enter the next step Processing;

Specifically, in step S03, the nickel powder precursor or cobalt powder precursor collected in step S02 is subjected to reduction treatment, the temperature of the reduction treatment is 300-450°C, preferably 360-420°C; the time of the reduction treatment is 2- 6 hours; the reducing atmosphere is not limited, and consists of reducing gas and inert gas, such as hydrogen, carbon monoxide; the inert atmosphere, such as nitrogen, helium, argon, etc.; in the reducing atmosphere, reducing The volume ratio of gas and inert gas is 1:0.1-2.5. After the reduction treatment in this step, the nickel powder precursor or cobalt powder precursor collected in step S02 is reduced into nickel powder or cobalt powder.

Specifically, in step S04 , the classification process of ultrasonic airflow crushing is the same as the aforementioned principle, which will not be repeated here. Wherein, in this step S04, the atmosphere of the jet crushing is an inert atmosphere, which is the same as the above, and will not be repeated here; the frequency of the ultrasonic jet crushing classifier is 30-70HZ/min. Because in the reduction treatment of step S03, water vapor can be produced, making the nickel powder or cobalt powder in this step grow up and agglomerate again, so that the prepared nickel powder or cobalt powder have different particle sizes, do not have uniformity, cannot meet the needs of production; the nickel powder or cobalt powder prepared in step S03 is subjected to the ultrasonic air flow crushing and classification treatment of step S04, so that the agglomerates in the nickel powder or cobalt powder are broken and dispersed; by adjusting the crushing frequency, a particle size small , narrow distribution of ultra-fine nickel powder or cobalt powder. After the treatment in step S04, the obtained ultrafine nickel powder or cobalt powder has a Fischer particle size of 0.5-1.0 micron FSSS and an oxygen content of 0.4-0.8%.

The preparation method of ultra-fine nickel powder or cobalt powder in the embodiment of the present invention uses ball milling and airflow crushing in combination, so that both hard aggregates and soft aggregates in the nickel powder precursor or cobalt powder precursor are broken and dispersed, Effectively prevent the re-agglomeration of the nickel powder precursor or cobalt powder precursor after ball milling; after the reduction treatment, the air-flow crushing is performed again, so that the soft aggregates in the nickel powder or cobalt powder can be broken and dispersed again, effectively preventing the reduction The re-agglomeration of the treated nickel powder or cobalt powder realizes the uniform particle size of the ultrafine nickel powder or cobalt powder.

The preparation method of the above-mentioned ultrafine nickel powder or cobalt powder is described in detail below in conjunction with specific examples.

Embodiment one

Please refer to Fig. 2, Fig. 2 shows the specific process of the preparation method of ultrafine cobalt powder according to the embodiment of the present invention, including the following steps:

The cobalt carbonate was ball milled for 10 hours at a speed of 100 rpm;

The cobalt carbonate after ball milling is subjected to airflow crushing and classification treatment, and the crushing frequency is 45HZ to obtain superfine particle powder of cobalt powder precursor;

The cobalt powder precursor powder is roasted under the conditions of nitrogen and hydrogen (nitrogen to hydrogen volume ratio 2.5:1) and a temperature of 380° C. to obtain cobalt powder;

The cobalt powder is subjected to airflow crushing and classification treatment, and the airflow crushing frequency is 40HZ to obtain ultrafine cobalt powder, cobalt powder FSSS0.75um, oxygen 0.55%.

Embodiment two

The preparation method of the superfine nickel powder of the embodiment of the present invention comprises the following steps:

Nickel oxalate was ball milled for 10 hours at a speed of 200 rpm;

The ball-milled nickel carbonate is subjected to airflow crushing and classification treatment, and the crushing frequency is 50HZ to obtain a nickel powder precursor. The nickel powder precursor is calcined under the conditions of carbon monoxide and nitrogen gas mixture (volume ratio of carbon monoxide and nitrogen: 1:0.1) and a temperature of 370° C. to obtain nickel powder;

The nickel powder or nickel powder is subjected to airflow crushing and classification treatment, and the airflow crushing frequency is 30HZ to obtain superfine nickel powder, nickel powder FSSS0.65um, oxygen content 0.61%.

Embodiment three

The preparation method of ultrafine cobalt powder in the embodiment of the present invention comprises the following steps:

Cobalt hydroxide was ball milled for 20 hours at a speed of 300 rpm;

The ball-milled cobalt hydroxide is subjected to airflow crushing and classification treatment, and the crushing frequency is 70HZ to obtain a cobalt powder precursor. The cobalt powder precursor is calcined under the conditions of hydrogen and nitrogen mixed gas (hydrogen and nitrogen volume ratio 1:1.25) and a temperature of 450° C. to obtain cobalt powder;

The cobalt powder is subjected to airflow crushing and classification treatment, and the airflow crushing frequency is 40HZ to obtain superfine cobalt powder. Cobalt powder FSSS0.55um, oxygen content 0.65%. Please refer to Fig. 3, Fig. 3 shows the electron microscope scanning photo of the ultrafine cobalt powder prepared in Example 3 of the present invention. It can be seen from Fig. 3 that the particle size of the cobalt powder is small and uniform.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the protection of the present invention. within range.

Claims (9)

1. a preparation method for extra-fine nickel powder or cobalt powder, comprises the steps:

By nickel powder precursor or cobalt powder precursor ball milling 3-20 hour;

Powdered nickel precursor body after ball milling or cobalt powder presoma are carried out airflow crash, classification process, collects powdered nickel precursor body or cobalt powder presoma; It is characterized in that, also comprise the steps:

The calcination process under reducing atmosphere and temperature are 300-450 DEG C of condition by described powdered nickel precursor body or cobalt powder presoma, obtains nickel powder or cobalt powder;

Described nickel powder or cobalt powder are carried out airflow crash, classification process, collects extra-fine nickel powder or cobalt powder;

Described powdered nickel precursor body be selected from nickelous carbonate, nickel oxalate, nickel oxide, nickel protoxide or nickel hydroxide one or more; Described cobalt powder presoma be selected from cobalt carbonate, cobalt oxalate, cobalt oxide, cobalt protoxide or cobalt hydroxide one or more.

2. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, rotating speed during described ball milling is 100-300 rev/min.

3. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, the time of described ball milling is 10-20 hour.

4. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, described milling atmosphere is air atmosphere.

5. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, the frequency of described air current classifying fragmentation is that 30-70HZ/ divides.

6. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, is characterized in that, described reducing atmosphere is the mixed atmosphere of reducibility gas and inert gas composition.

7. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, the time of described calcination process is 2-6 hour.

8. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, described nickel powder or cobalt powder are carried out in airflow crash, classification treatment step, the atmosphere of airflow crash is inert atmosphere.

9. the preparation method of extra-fine nickel powder as claimed in claim 1 or cobalt powder, it is characterized in that, described nickel powder or cobalt powder oxygen content are 0.4-0.8%.