CN103128304A - Method for preparing spherical cobalt powder - Google Patents
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- CN103128304A CN103128304A CN2011103946844A CN201110394684A CN103128304A CN 103128304 A CN103128304 A CN 103128304A CN 2011103946844 A CN2011103946844 A CN 2011103946844A CN 201110394684 A CN201110394684 A CN 201110394684A CN 103128304 A CN103128304 A CN 103128304A
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Abstract
The invention provides a method for preparing spherical cobalt powder. The method includes the following steps of mixing CoCL2.6H2O with polyhydric alcohols, adding alkali liquor, preparing mixed solutions with the cobalt concentration of 5-30g/L, heating for 196-198 DEG C, reflux carried out for 2-4 hours, suction filtration, washing, hydrogen drying and reduction under the temperature of 300-500 DEG C, and preparing the cobalt powder. According to the method, the cobalt salt CoCL2.6H2O is directly utilized to be reacted with the polyhydric alcohols to prepare the spherical cobalt powder, and consumed time is shortened by 40%-60% of the time of a traditional cobalt salt reduction method. According to the method, the polyhydric alcohols and the hydrogen drying and the reduction under a high temperature are adopted, not only is spherical appearance of the polyhydric alcohol reduction cobalt powder saved, but also purity of the cobalt powder is improved, under the condition that the cobalt concentration is up to 5-30g/L in an industrialized process, the prepared spherical cobalt powder has good appearance characteristics, the grain size of products can be controlled, and the cobalt conversion rate is up to more than 98%.
Description
Technical field
The present invention relates to the raw material cobalt powder in carbide alloy field, relate in particular to a kind of method for preparing spherical cobalt powder.
Background technology
Carbide alloy usually is mixed with by refractory carbide and binding metal (such as cobalt powder) etc. and forms.The preparation of carbide alloy also has very high requirement to its granularity and pattern except the purity requirement strictly to cobalt powder.China adopts hydrogen reduction method to produce cobalt powder mostly, and the cobalt powder skewness that makes is dendroid, and this has limited the development of high-performance rigid alloy to a certain extent.
Spherical cobalt powder has the following advantages: is form of spherical particles, has minimum porosity and relative sliding friction factor, and superior autgmentability and ductility; When mixing with other material, show good miscibilty, therefore can avoid the appearance in cobalt pond in carbide alloy, be conducive to improve the combination property of carbide alloy.Therefore, how prepared sizes spherical cobalt powder even and good dispersion is the problem that the various countries scientist falls over each other to study.
At present, the known method for preparing spherical cobalt powder mainly comprises: polyalcohol cobalt salt reducing process, high-pressure water spray method and microemulsion method.Wherein, polyalcohol cobalt salt reducing process mainly comprises: the first step, and with cobalt salt (CoSO
47H
2O or Co (NO
3)
26H
2O) be dissolved in distilled water, heat and stir, with NaOH or NH
3H
2The O precipitation, suction filtration, washing and oven dry make Co (OH)
2Second step is with Co (OH)
2Be precursor and polyalcohol (for example ethylene glycol) reaction, reduction makes spherical cobalt powder.The shortcoming of the method is as follows: (1) is that two steps are synthetic, and technological process is consuming time; (2) only limit to bibliographical information, be the experimental stage, cobalt concentration is too low, and correspondingly the cobalt conversion ratio is also lower; (3) be unfavorable for suitability for industrialized production, because the bad operation of the reaction condition of 200 ℃ of left and right and realization, and the more important thing is that C content (organic ethylene glycol introducing) and O content (introducing in the filtering drying process) in spherical cobalt powder are higher, thereby caused the purity of spherical cobalt powder not high, may affect the product shape characteristic because enlarge-effect occurring if directly carry out expanding production.
Summary of the invention
For addressing the above problem, the present invention aim to provide a kind of technique simple, have high conversion and method that be suitable for suitability for industrialized production high-purity spherical cobalt powder.
The invention provides a kind of method for preparing spherical cobalt powder, comprise the following steps: get CoCl
26H
2O mixes with polyalcohol, adds alkali lye, is mixed with the mixed solution that cobalt concentration is 5～30g/L, is heated to 196～198 ℃, refluxed 2～4 hours, and suction filtration, washing, hydrogen desiccation and reduction at 300～500 ℃ of temperature make spherical cobalt powder.
Compare traditional polyalcohol cobalt salt reducing process, the present invention directly adopts CoCl
26H
2O and polyalcohol carry out reduction reaction, have saved synthetic Co (OH)
2Process, technique is simpler, thereby has saved time cost.
Cobalt concentration in mixed solution of the present invention is 5～30g/L, and the product that makes in large-scale industrialization is produced still can keep good shape characteristic, and the cobalt conversion ratio can reach up to more than 98%.Preferably, in mixed solution, cobalt concentration is 10～28g/L.More preferably, in mixed solution, cobalt concentration is 25g/L.
In the commercial process of existing polyalcohol cobalt salt reduction method for preparing spherical cobalt powder, cobalt powder easily oxidized and carbon content exceeds standard.The present invention has adopted the way of polyol process and at high temperature hydrogen desiccation and reduction, and the spherical morphology of so both having preserved the polyol process cobalt powder has also improved the purity of cobalt powder, satisfies the demand of suitability for industrialized production.Preferably, add nitrogen and/or helium in hydrogen desiccation and reduction process.
CoCl
26H
2O provides the cobalt ions storehouse for reaction.CoCl
26H
2Phase in the middle of O and polyalcohol generate by reaction, subsequently in the middle of phased soln, the cobalt that is dissolved in solution is become metallic cobalt by polyol process.The effect of polyalcohol has three: the one, make precursor compound CoCl as liquid phase
26H
2O is in suspended state, increases the contact of reactant, thereby adds the efficient of fast response, and the 2nd, as the reducing agent of reaction, the 3rd, the surface that polyalcohol is adsorbed on cobalt powder has formed the electronegative film of one deck and has prevented that the reunion of cobalt powder particle from stoping new nucleus to generate simultaneously.Preferably, the concentration of polyalcohol in mixed solution is 8～80g/L.Preferably, polyalcohol can be ethylene glycol or 1,2 propane diols.Ethylene glycol boiling point lower (197 ℃), reusable edible after distilation.
The purpose that adds alkali lye is catalysis CoCl
26H
2Reaction between O and polyalcohol.In alkaline solution, polyalcohol is oxidized when oxidizing potential is low, along with OH
-Increase, the oxidizing potential of polyalcohol raises, the reaction that makes cobalt in solution be reduced into metallic cobalt is more easily carried out.Preferably, n (OH in alkali lye
-) with the ratio of n (Co) be 1～8: 1.Alkali lye can be NaOH solution etc.Preferably, alkali lye is NaOH solution, n (NaOH): n (Co)=4.
Preferably, mixed solution of the present invention further comprises sodium acetate.In the middle of being conducive to the adding of sodium acetate catalysis, the phase complexing becomes the ionic condition dissolving to enter solution, makes reaction more easily carry out.
A kind of method for preparing spherical cobalt powder provided by the invention has following beneficial effect:
(1) directly use cobalt salt CoCl
26H
2O and polyol process reaction preparation ball-type cobalt powder, technique is simple, compares traditional polyalcohol cobalt salt reducing process and shortens for 40%～60% time;
(2) the present invention has adopted the way of hydrogen reducing drying under polyol process and high temperature, so both preserved the spherical morphology of polyol process cobalt powder, also improved the purity of cobalt powder, satisfy the demand of suitability for industrialized production, in the situation that in course of industrialization cobalt content concentration up to 5～30g/L, the spherical cobalt powder that makes has good shape characteristic, and product granularity is controlled, and the cobalt conversion ratio is up to more than 98%;
(3) product that makes of the present invention is spherical cobalt powder, and wherein C content is lower, so purity is high, has minimum porosity and relative sliding friction factor, and superior autgmentability and ductility, and is dispersed fabulous; When mixing with other material, show good miscibilty, therefore can avoid the appearance in cobalt pond in carbide alloy, be conducive to improve the combination property of carbide alloy.
Description of drawings
Fig. 1 is the Electronic Speculum figure A of the spherical cobalt powder that makes of the present invention;
Fig. 2 is the Electronic Speculum figure B of the spherical cobalt powder that makes of the present invention;
Fig. 3 is the Electronic Speculum figure C of the spherical cobalt powder that makes of the present invention.
The specific embodiment
The following stated is the preferred embodiment of the present invention; should be pointed out that for those skilled in the art, under the prerequisite that does not break away from the principle of the invention; can also make some improvements and modifications, these improvements and modifications also are considered as protection scope of the present invention.
Embodiment one
A kind of method for preparing spherical cobalt powder comprises the following steps: get CoCl
26H
2O mixes with ethylene glycol, adds NaOH solution, n (NaOH): n (Co)=4, be mixed with mixed solution, wherein cobalt concentration is 30g/L, and glycol concentration is 80g/L, is heated to 198 ℃, refluxed 2 hours, suction filtration, washing, hydrogen desiccation and reduction under four sections high temperature, every section temperature is respectively: 416 ℃, 420 ℃, 426 ℃ and 415 ℃, the flow of hydrogen is 4m
3/ h, also adding inbound traffics in this process is 6m
3The nitrogen of/h continues 4h, makes spherical cobalt powder.
The spherical cobalt powder particle mean size that the present invention makes is 1～10 μ m, and pattern is spherical, is evenly distributed, and purity is 99.96%.
Embodiment two
A kind of method for preparing spherical cobalt powder comprises the following steps: get CoCl
26H
2O mixes with ethylene glycol, adds NaOH solution,
N (NaOH): n (Co)=8,Be mixed with mixed solution, wherein cobalt concentration is 28g/L, and glycol concentration is 60g/L, is heated to 197 ℃, refluxed 3 hours, suction filtration, washing, hydrogen desiccation and reduction under four sections high temperature, every section temperature is respectively: 310 ℃, 317 ℃, 317 ℃ and 310 ℃, the flow of hydrogen is 4m
3/ h, nitrogen flow are 64m
3/ h continues 12h, makes spherical cobalt powder.
The spherical cobalt powder particle mean size that the present invention makes is 1～10 μ m, and pattern is spherical, is evenly distributed, and purity is 99.95%.
Embodiment three
A kind of method for preparing spherical cobalt powder comprises the following steps: get CoCl
26H
2O mixes with ethylene glycol, adds NaOH solution,
N (NaOH): n (Co)=1,Be mixed with mixed solution, wherein cobalt concentration is 10g/L, and glycol concentration is 40g/L, is heated to 196 ℃, refluxed 4 hours, and suction filtration, washing, hydrogen and nitrogen mixture soma are dry and reduce 6h at 500 ℃ of temperature, make spherical cobalt powder.
The spherical cobalt powder particle mean size that the present invention makes is 1～10 μ m, and pattern is spherical, is evenly distributed, and purity is 99.96%.
Embodiment four
A kind of method for preparing spherical cobalt powder comprises the following steps: get CoCl
26H
2O mixes with ethylene glycol, adds NaOH solution, is mixed with mixed solution, and wherein cobalt concentration is 25g/L, glycol concentration is 8g/L, is heated to 197 ℃, refluxed 2 hours, and suction filtration, washing, hydrogen and nitrogen mixture soma are dry and reduce 8h at 300 ℃ of temperature, make spherical cobalt powder.
The spherical cobalt powder particle mean size that the present invention makes is 1～10 μ m, and pattern is spherical, is evenly distributed, and purity is 99.95%.
Embodiment five
A kind of method for preparing spherical cobalt powder comprises the following steps: get CoCl
26H
2O and 1,2 mixed with propylene glycol add NaOH solution, n (NaOH): n (Co)=4 is mixed with mixed solution, and wherein cobalt concentration is 30g/L, 1,2 propane diols concentration are 80g/L, are heated to 197 ℃, reflux 2 hours, suction filtration, washing, hydrogen desiccation and reduction 6h, make spherical cobalt powder at 300 ℃ of temperature.
The spherical cobalt powder particle mean size that the present invention makes is 1～10 μ m, and pattern is spherical, is evenly distributed, and purity is 99.95%.
Embodiment six
A kind of method for preparing spherical cobalt powder comprises the following steps: get CoCl
26H
2O and 1,2 mixed with propylene glycol add NaOH solution and sodium acetate, be mixed with mixed solution, wherein cobalt concentration is 5g/L, and 1,2 propane diols concentration is 8g/L, be heated to 196 ℃, refluxed 4 hours, suction filtration, washing, at 500 ℃ of temperature hydrogen and nitrogen mixture soma dry and the reduction 4h, make spherical cobalt powder.
The spherical cobalt powder particle mean size that the present invention makes is 1～10 μ m, and pattern is spherical, is evenly distributed, and purity is 99.95%.
Effect embodiment
Be the performance of the spherical cobalt powder that preparation method of the present invention is described better and makes, the spy provides the parameter in preparation process as follows.
1. the physical and chemical index of original cobalt powder
The physical and chemical index of the original cobalt powder of table 1.
| Co％ | C％ | O％ | Na％ | Cl％ | Fsssμm | HB/g/cm 3 | Color | |
| Minimum | 97.57 | 0.44 | 0.41 | 0.011 | 0.003 | 1.3 | 1.22 | Grey |
| Maximum | 99.1 | 0.6067 | 0.47 | 0.035 | 0.0294 | 9.9 | 1.88 | Grey |
| The typical case | 98.34 | 0.5435 | 0.45 | 0.032 | 0.0117 | 1.3 | 1.88 | Grey |
CoCl
26H
2O mixes with ethylene glycol, adds NaOH solution, and n (NaOH): n (Co)=4 is mixed with the mixed solution that cobalt concentration is 5～30g/L, is heated to 196～198 ℃, refluxed 2～4 hours, and suction filtration, washing makes original cobalt powder.As can be seen from Table 1, the Fsss granularity of the original cobalt powder that the present invention makes is from 1.3～9.9 adjustable, and O content is moderate, and C content is higher, and Co content is on the low side.
2. the indices of spherical cobalt powder
The above-mentioned original cobalt powder for preparing is placed at 300～500 ℃ of temperature hydrogen and the nitrogen mixture soma is dry and reduction, makes spherical cobalt powder.Because the pattern of cobalt powder in reduction process possesses inheritance, so the cobalt powder morphology that the purity of preparation uprises is also spherical, satisfy the standard of industrial cobalt powder.
The indices of table 2, spherical cobalt powder
| Numbering | Co％ | C％ | O％ | Hydrogen | Fsssμm | Color | |
| 1, original reduction cobalt powder | 98.34 | 0.5435 | 0.45 | 0.68％ | 1.3 | Grey | |
| 2,323 ℃ of reduction 10h | 99.64 | 0.0502 | 0.39 | 0.57％ | 1.45 | Grey | |
| 3,417 ℃ of reduction 5.3h | 99.28 | 0.036 | 0.37 | 0.42％ | 1.75 | Grey | |
| 4,500 ℃ of reduction 5.1h | 99.75 | 0.0325 | 0.38 | 0.49％ | 3.81 | Grey |
As can be seen from Table 2:
1) the direct original cobalt powder that obtains of reduction of ethylene glycol because the organic C that introduced of ethylene glycol, and can be introduced O in the process of washing, suction filtration and oven dry, so C, O content are higher, Co content is on the low side, has caused cobalt powder purity inadequate;
2) original cobalt powder is by the reduction of hydrogen stream in different temperatures, C, O content reduce, Co content raises, purity improves, it is large that the Fsss particle mean size becomes a little, make spherical cobalt powder, become particle mean size after large still meet the requirements (being 1～10 μ m as Fig. 1, Fig. 2 and spherical cobalt powder particle mean size shown in Figure 3);
3) original cobalt powder reduces in hydrogen stream, and the pattern of cobalt powder has inheritance, so the spherical cobalt powder of this method preparation combines the advantage of ethylene glycol and hydrogen reducing cobalt powder, has prepared the spherical cobalt powder that satisfies industrial requirement.
Claims (9)
1. a method for preparing spherical cobalt powder, is characterized in that, comprises the following steps: get CoCl
26H
2O mixes with polyalcohol, adds alkali lye, is mixed with the mixed solution that cobalt concentration is 5～30g/L, is heated to 196～198 ℃, refluxed 2～4 hours, and suction filtration, washing, hydrogen desiccation and reduction at 300～500 ℃ of temperature make spherical cobalt powder.
2. the method for claim 1, is characterized in that, the concentration of described polyalcohol in mixed solution is 8～80g/L.
3. the method for claim 1, is characterized in that, described polyalcohol is ethylene glycol or 1,2 propane diols.
4. the method for claim 1, is characterized in that, the n (OH in described alkali lye
-) with the ratio of n (Co) be 1～8: 1.
5. the method for claim 1, is characterized in that, described alkali lye is NaOH solution, n (NaOH): n (Co)=4.
6. the method for claim 1, is characterized in that, in described mixed solution, cobalt concentration is 10～28g/L.
7. method as claimed in claim 6, is characterized in that, in described mixed solution, cobalt concentration is 25g/L.
8. the method for claim 1, is characterized in that, described mixed solution further comprises sodium acetate.
9. the method for claim 1, is characterized in that, adds nitrogen and/or helium in described hydrogen desiccation and reduction process.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105170991A (en) * | 2015-08-20 | 2015-12-23 | 河北工业大学 | Method for preparing superfine metallic cobalt powder |
| CN111154995A (en) * | 2020-01-02 | 2020-05-15 | 荆门德威格林美钨资源循环利用有限公司 | Superfine tungsten carbide based on doped bonding phase and preparation method thereof |
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| KR20070094301A (en) * | 2006-03-17 | 2007-09-20 | 주식회사 나노테크 | Manufacturing method for ultra fine composite powder of tungsten carbide and cobalt |
| CN101376174A (en) * | 2008-09-27 | 2009-03-04 | 浙江华友钴业股份有限公司 | Method for preparing superfine spherical cobalt powder |
| CN101653830A (en) * | 2009-11-09 | 2010-02-24 | 昆明贵金属研究所 | Method for preparing superfine cobalt powder in close-packed hexagonal structure or face-centered cubic structure by hydrogen reduction |
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2011
- 2011-12-02 CN CN201110394684.4A patent/CN103128304B/en active Active
Patent Citations (6)
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|---|---|---|---|---|
| DE3636980A1 (en) * | 1985-10-31 | 1987-05-07 | Gte Prod Corp | METHOD FOR PRODUCING A COBALT METAL POWDER |
| CN1261565A (en) * | 1999-01-21 | 2000-08-02 | 中国科学技术大学 | Method for preparing nanometre metal cobalt powder or nickel powder |
| CN1686650A (en) * | 2005-05-18 | 2005-10-26 | 北京科技大学 | Precipitation reduction method of preparing nano-cobalt powder |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105170991A (en) * | 2015-08-20 | 2015-12-23 | 河北工业大学 | Method for preparing superfine metallic cobalt powder |
| CN111154995A (en) * | 2020-01-02 | 2020-05-15 | 荆门德威格林美钨资源循环利用有限公司 | Superfine tungsten carbide based on doped bonding phase and preparation method thereof |
| CN111154995B (en) * | 2020-01-02 | 2021-08-20 | 荆门美德立数控材料有限公司 | Superfine tungsten carbide based on doped bonding phase and preparation method thereof |
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