CN1299866C - Method for preparing fibrous nickel powder and nickelous oxide powder - Google Patents

Abstract

The invention relates to a preparation process of a special powder functional material, in particular to a preparation method of fibrous nickel powder and nickelous oxide powder, which is characterized by comprising the following steps: by precipitation-conversion thermal decomposition, Ni is obtained at normal temperature and pressure²⁺-NH₃-NH₄ ⁺-SG^n--C₂O₄ ^2--H₂Synthesizing nickel powder or nickel protoxide precursor precipitate in an O system; thermally decomposing the precursor in an oxidizing atmosphere to obtain fibrous nickelous oxide powder; and thermally decomposing the precursor in a non-oxidizing atmosphere to obtain the fibrous nickel powder. The surface anti-oxidation treatment of the fibrous nickel powder is carried out in the same set of equipment under the regulation and control of temperature and atmosphere. The whole preparation process is safe and reliable, and is non-toxic and pollution-free; the nickel powder and the nickelous oxide powder produced by the method are fibrous, have nanoscale granularity, are porous and have large specific surface area; the nickel powder has strong oxidation resistance, and the spherical nickel protoxide powder can be obtained after the fine grinding of the nickel protoxide powder, and the powder can meet the requirements of various purposes.

Description

Preparation method of fibrous nickel powder and nickelous oxide powder

Technical field:

The invention relates to a preparation process of a special powder functional material, in particular to a preparation method of fibrous nickel powder and nickelous oxide powder.

Background technique:

Special nickel powder has many special functions in the fields of catalyst, battery material, conductive paste, electromagnetic wave absorbing material, microporous filter material, powder metallurgy and other fields due to its great volume effect, surface effect and morphology characteristics. As a new type of material, more and more attention has been paid to it, and its application is wide and the demand is large. The currently used special nickel powder is mainly produced by the carbonyl method. The method is carried out under high temperature and high pressure, the nickel carbonyl is flammable, explosive, toxic and pollutes the environment, the process control is complex, and the particle size of the product can only reach the micron level, so the application range is limited. Although Japanese Patent JP64-28309 discloses a method for preparing acicular or fibrous nickel powder, the precursor synthesis of this method is carried out in an autoclave, the processing capacity is limited, and high temperature and pressure are required, and the cost is high. complex.

Nickel oxide is a promising important inorganic material, which is widely used in catalyst materials, battery materials, magnetic materials, electronic materials, glass, enamel, ceramic materials and so on. At present, the preparation method of nickelous oxide powder at home and abroad is generally obtained by calcination with nickel carbonate, nitrate or hydroxide as raw material, and nickel chloride is also used as raw material, adding ammonium oxalate to generate nickel oxalate precipitation, and then It is obtained by calcination in the air; the products obtained by these methods have high impurity content, coarse particle size, and no fibrous morphology. In addition, there are some other methods for preparing nickel oxide powder, but most of these methods focus on the preparation of spherical nickel oxide or nano-film, and there are few reports on fibrous nickel oxide powder.

Invention content:

The object of the present invention is to overcome the weak point of above-mentioned method, a kind of preparation method of fibrous nickel powder and nickelous oxide powder is provided. The method is safe, reliable, non-toxic, non-polluting, and environmentally friendly; using one process and one set of devices, two ultrafine powder materials can be obtained by changing the atmosphere of thermal decomposition, and it is easy to realize industrialization; the prepared nickel powder has a purity of High, small particle size, large specific surface area, strong oxidation resistance, can meet the requirements of nickel powder in many fields at home and abroad.

The technical solution of the present invention: control the shape and particle size of the precipitate in the solution, and then thermally decompose the dried precipitate under a certain temperature and atmosphere control to obtain the metal and its oxide powder with the desired shape and particle size .

The preparation method of fibrous nickel powder is characterized in that: first, the soluble nickel salt solution and the composite precipitant solution formed by stoichiometric oxalic acid or ammonium oxalate or sodium oxalate, ammonia and dispersant PVP are added to the reactor through a feeding device, exist

Ni ²⁺ -NH ₃ -NH ₄ ⁺ -SG ^n- -C ₂ O ₄ ^2- -H ₂ O

Composite precipitation transformation is carried out in the system, the temperature is controlled at 55-85°C, the pH value is 7.0-9.0, and the initial Ni ²⁺ concentration in the feed liquid is 0.4-1.2mol/L; then the composite precipitate obtained after the reaction is completed is washed , filtered and dried to become the precursor of nickel powder; then the nickel powder precursor is placed in an electric furnace regulated by PID, the temperature is controlled at 350-650°C, and thermal decomposition is carried out under the control of a non-oxidizing atmosphere; the thermal decomposition is completed The finished nickel powder is then cooled and subjected to surface anti-oxidation treatment to obtain fibrous nickel powder, wherein SG ^n- in the composite precipitation conversion system represents the acid radical Cl-, SO ₄ ^2- , CH ₃ COO ^- or NO ₃ ^- .

The non-oxidizing atmosphere mentioned in the preparation method of the above-mentioned fibrous nickel powder includes hydrogen, hydrogen plus nitrogen, hydrogen plus inert gas or pure inert gas atmosphere.

The surface anti-oxidation treatment method mentioned in the preparation method of the above-mentioned fibrous nickel powder is a carbon dioxide gas adsorption method under temperature control.

The preparation method of fibrous nickelous oxide powder is characterized in that: first, the soluble nickel salt solution and the composite precipitant solution composed of oxalic acid or ammonium oxalate or sodium oxalate, ammonia and dispersant PVP are added to the reactor through the feeding device in

Ni ²⁺ -NH ₃ -NH ₄ ^- -SG ^n- -C ₂ O ₄ ^2- -H ₂ O

Composite precipitation transformation is carried out in the system, the temperature is controlled at 55-85°C, the pH is 7.0-9.0, and the initial Ni ²⁺ concentration in the feed liquid is 0.4-1.2mol/l; then the composite precipitate obtained after the reaction is completed is washed, Filtration and drying is the precursor of nickelous oxide powder; then the precursor of nickelous oxide is placed in a PID-regulated electric furnace, the temperature is controlled at 350-800 ° C, and thermal decomposition is carried out under the control of an oxidative atmosphere; The fibrous nickel oxide powder can be obtained by natural cooling of the thermally decomposed nickel oxide powder. SG ^n- in the composite precipitation transformation system represents the acid radical Cl ^- , SO ₄ ^2- , CH ₃ COO ^- or NO ₃ ^- .

The oxidative atmosphere mentioned in the preparation method of the above-mentioned fibrous nickel oxide powder includes oxygen or air atmosphere.

Said soluble nickel salt in the preparation method of above-mentioned fibrous nickel powder and nickelous oxide powder comprises nickel chloride hexahydrate, nickel sulfate hexahydrate, nickel acetate tetrahydrate, nickel nitrate hexahydrate or nickel chloride solution, nickel sulfate solution , Nickel acetate solution, nickel nitrate solution.

The composite precipitant mentioned in the preparation method of the fibrous nickel powder and nickel oxide powder includes oxalic acid, ammonium oxalate or sodium oxalate, ammonia, and a dispersant PVP.

The stoichiometric metering coefficient mentioned in the preparation method of the above-mentioned fibrous nickel powder and nickel oxide powder is 1.0-20 in the molar ratio of nickel to oxalic acid or ammonium oxalate in the composite precipitant.

In the preparation method of the above-mentioned fibrous nickel powder and nickelous oxide powder, the pH value is adjusted with ammonia water, and the ammonia-nickel molar ratio is controlled to be 2.0-10.0.

The present invention has the following advantages:

1. Using precipitation conversion thermal decomposition method, nickel powder or nickelous oxide powder is produced in Ni ²⁺ -NH ₃ -NH ₄ ⁺ -SG ^n- -C ₂ O ₄ ^2- -H ₂ O system at normal temperature and pressure The synthesis process of the precursor and the subsequent thermal decomposition process of the precursor are safe, reliable, non-toxic and pollution-free, and friendly to the environment.

2. The anti-oxidation treatment on the surface of the fibrous nickel powder after thermal decomposition is carried out in the same device under the control of temperature and atmosphere.

3. nickel powder and nickelous oxide powder produced according to the present invention are fibrous, and particle size is nanoscale, porous, large specific surface area, wherein nickel powder anti-oxidation ability is strong; And fibrous nickelous oxide powder can also be finely ground Spherical nickel oxide powder is obtained; these powders can meet the requirements of various purposes.

Description of drawings:

Fig. 1: the preparation process flowchart of fibrous nickel powder and nickelous oxide powder in the present invention

Fig. 2: XRD pattern of the precursor of fibrous nickel powder or nickelous oxide powder in the present invention

Fig. 3: XRD pattern of fibrous nickel powder in the present invention

Fig. 4: XRD pattern of fibrous nickelous oxide powder in the present invention

Figure 5: SEM image of the precursor of fibrous nickel powder or nickel oxide powder in the present invention

Figure 6: SEM image of fibrous nickel powder in the present invention

Figure 7: SEM image of fibrous nickel oxide powder in the present invention

Figure 8: SEM image of fibrous nickel oxide powder in the present invention after grinding

Fig. 1 has described the preparation process of fibrous nickel powder and nickelous oxide powder:

①Put the soluble nickel salt solution and the composite precipitant solution into the reactor respectively through the feeding device, and in Ni ²⁺ -NH ₃ -NH ₄ ⁺ -SG ^n- -C ₂ O ₄ ^2- -H ₂ O (SG ^n- represents Acid radical Cl ^- , SO ₄ ^2- , NO ₃ ^- or CH ₃ COO ^- ) system for complex precipitation conversion reaction, controlled temperature is 55-85°C, pH value is 7.0-9.0, and the initial Ni ²⁺ concentration in the feed solution is 0.4～1.2mol/l;

②Washing, filtering and drying the composite precipitate obtained after the completion of the reaction is nickel powder or nickel oxide powder precursor;

③Put the precursor into an electric furnace regulated by PID, control the temperature at 350-650°C, and conduct thermal decomposition under the control of a non-oxidizing atmosphere; then cool and treat the surface to room temperature in the same device to obtain a fibrous nickel powder;

④Put the precursor into an electric furnace regulated by PID, control the temperature at 350-800°C, and conduct thermal decomposition under the control of an oxidative atmosphere to obtain fibrous nickel oxide powder.

After testing, its physical and chemical properties are as follows:

Fibrous nickel powder:

Particle size: short diameter ≤ 100nm; long diameter: ≥ 10μm; specific surface area: ≥ 13m ² /g;

Carbon: ≤0.01wt%; Sulfur: ≤0.001wt%; Iron: ≤0.01wt%; Oxygen: ≤0.15wt%

Fibrous nickel oxide powder:

Particle size: short diameter ≤ 150nm; long diameter: ≥ 10μm; specific surface area: ≥ 10m ² /g;

Carbon: ≤0.01wt%; Sulfur: ≤0.001wt%; Iron: ≤0.01wt%;

Detailed ways:

Example 1:

Add the nickel chloride solution and the composite precipitant solution composed of ammonia, ammonium oxalate and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ -Cl ^- -C ₂ O ₄ ^2- - Composite precipitation conversion is carried out in the H ₂ O system, the temperature is controlled at about 60°C, the pH of the solution is adjusted to about 8.5 with ammonia water, the initial Ni ²⁺ concentration in the feed solution is 0.8mol/l, and the C ₂ O ₄ ^2- concentration is 0.88 mol/L.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of nickel powder. After that, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at about 450 ° C, and the The thermal decomposition is carried out under the control of the atmosphere of (H ₂ +N ₂ ). After the thermal decomposition is completed, it is cooled under a carbon dioxide atmosphere and the surface is anti-oxidized to room temperature. The gray-black powder taken out from the burning boat after being released from the furnace is the fibrous nano-scale special nickel powder.

Example 2:

Add the nickel nitrate solution and the composite precipitant solution composed of ammonia, ammonium oxalate and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ -NO ₃ ^- -C ₂ O ₄ ^2- - Composite precipitation conversion is carried out in the H ₂ O system, the temperature is controlled at about 65°C, the pH value is about 8.6, the initial Ni ²⁺ concentration in the feed solution is 0.6 mol/L, and the C ₂ O ₄ ^2- concentration is 0.72 mol/L.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of nickel powder. After that, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at about 400 ° C, and in The thermal decomposition is carried out under the control of the atmosphere of _N2 . After the thermal decomposition is completed, it is cooled under the carbon dioxide atmosphere and the surface is anti-oxidized to room temperature.

Example 3:

Add the nickel sulfate solution and the composite precipitant solution composed of ammonia, ammonium oxalate and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ --NO ₃ ^- -C ₂ O ₄ ^2- Composite precipitation transformation is carried out in the -H ₂ O system, the temperature is controlled at 70°C, the pH value is 8.8, the initial Ni ²⁺ concentration in the feed solution is 0.5 mol/l, and the C ₂ O ₄ ^2- concentration is 0.65 mol/l.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of nickel powder. Afterwards, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at 360 ° C, and in ( The thermal decomposition is carried out under the control of the atmosphere of H ₂ +N ₂ ). After the thermal decomposition is completed, it is cooled under the carbon dioxide atmosphere and the surface is anti-oxidized to room temperature. Special nickel powder.

Example 4:

Add the nickel acetate solution and the composite precipitant solution composed of ammonia, oxalic acid and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ --NO ₃ ^- -C ₂ O ₄ ^2- - Composite precipitation conversion was carried out in the H ₂ O system, the temperature was controlled at 65°C, the pH value was 8.7, the initial Ni ²⁺ concentration in the feed solution was 0.7 mol/l, and the C ₂ O ₄ ^2- concentration was 0.85 mol/l.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of nickel powder. After that, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at 420 ° C and heated in N _2. Thermal decomposition is carried out under the control of the atmosphere. After the thermal decomposition is completed, it is cooled under the carbon dioxide atmosphere and the surface is anti-oxidized to room temperature.

Example 5:

Add the nickel chloride solution and the composite precipitant solution composed of ammonia, ammonium oxalate and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ --NO ₃ ^- -C ₂ O ₄ ^{2 -} Carry out complex precipitation transformation in the -H ₂ O system, control the temperature at about 60°C, adjust the pH value of the solution with ammonia water to about 8.5, the initial Ni ²⁺ concentration in the feed solution is 0.8mol/l, and the C ₂ O ₄ ^2- concentration It is 0.88mol/l.

After the completion of the reaction, the composite precipitate obtained after washing, filtering and drying is the precursor of NiO powder. Afterwards, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at 400 ° C, and the The thermal decomposition is carried out under the air atmosphere. After the thermal decomposition is completed, it is cooled to room temperature immediately. The black or light green powder taken out from the burning boat after being released from the furnace is the fibrous nickel oxide powder.

Embodiment 6:

Add the nickel nitrate solution and the composite precipitant solution composed of ammonia, sodium oxalate and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ -NO ₃ ^- -C ₂ O ₄ ^2- - Composite precipitation transformation is carried out in the H ₂ O system, the temperature is controlled at about 65°C, the pH value is about 8.6, the initial Ni ²⁺ concentration in the feed solution is 0.6 mol/l, and the C ₂ O ₄ ^2- concentration is 0.72 mol/l.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of NiO powder. After that, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at 450 °C. Thermal decomposition is carried out under an oxygen atmosphere. After the thermal decomposition is completed, it is then cooled to room temperature. The black or light green powder taken out from the burning boat after being released from the furnace is fibrous nickel oxide powder.

Embodiment 7:

Add the nickel sulfate solution and the composite precipitant solution composed of ammonia, ammonium oxalate and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ -NO ₃ ^- -C ₂ O ₄ ^2- - Composite precipitation transformation was carried out in the H ₂ O system, the temperature was controlled at 70°C, the pH value was 8.8, the initial Ni ²⁺ concentration in the feed solution was 0.5 mol/l, and the C ₂ O ₄ ^2- concentration was 0.65 mol/l.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of nickelous oxide powder. After that, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at 500°C. The thermal decomposition is carried out under the air atmosphere. After the thermal decomposition is completed, it is cooled to room temperature immediately. The black or light green powder taken out from the burning boat after being released from the furnace is the fibrous nickel oxide powder.

Embodiment 8:

Add the nickel acetate solution and the composite precipitant solution composed of ammonia, oxalic acid and dispersant PVP into the reactor through the feeding device, in Ni ²⁺ -NH ₃ -NH ₄ ⁺ --NO ₃ ^- -C ₂ O ₄ ^2- - Composite precipitation conversion was carried out in the H ₂ O system, the temperature was controlled at 65°C, the pH value was 8.7, the initial Ni ²⁺ concentration in the feed solution was 0.7 mol/l, and the C ₂ O ₄ ^2- concentration was 0.85 mol/l.

After the reaction is completed, the obtained composite precipitate is washed, filtered and dried to become the precursor of NiO powder. After that, the precursor is put into a burning boat and placed in a PID-regulated electric furnace. The temperature is controlled at 650 °C. Thermal decomposition is carried out under an oxygen atmosphere. After the thermal decomposition is completed, it is then cooled to room temperature. The black or light green powder taken out from the burning boat after being released from the furnace is fibrous nickel oxide powder.

Claims (8)

1. The preparation method of fibrous nickel powder is characterized in that: at first the composite precipitant solution that soluble nickel salt solution and oxalic acid or ammonium oxalate or sodium oxalate and ammonia and dispersant PVP form is added in the reactor through feeding device by stoichiometric ,exist Ni ²⁺ -NH ₃ -NH ₄ ⁺ -SG ^n- -C ₂ O ₄ ^2- -H ₂ O Composite precipitation transformation is carried out in the system, the temperature is controlled at 55-85°C, the pH value is 7.0-9.0, and the initial Ni ²⁺ concentration in the feed liquid is 0.4-1.2mol/l; then the composite precipitate obtained after the reaction is completed is washed , filtered and dried to become the precursor of nickel powder; then the nickel powder precursor is placed in an electric furnace regulated by PID, the temperature is controlled at 350-650°C, and thermal decomposition is carried out under the control of a non-oxidizing atmosphere; after the thermal decomposition is completed The nickel powder is then cooled and treated to prevent oxidation on the surface to obtain fibrous nickel powder. SG ^n- in the composite precipitation transformation system represents the acid radical Cl ^- , SO ₄ ^2- , CH ₃ COO ^- or NO ₃ ^- . 2. The method according to claim 1, characterized in that the non-oxidizing atmosphere is hydrogen, hydrogen plus nitrogen, hydrogen plus inert gas or pure inert gas. 3. The method according to claim 1, characterized in that said surface anti-oxidation treatment method refers to a carbon dioxide gas adsorption method under temperature control. 4. The method according to claim 1, wherein the stoichiometric stoichiometric coefficient is characterized in that the molar ratio of oxalic acid or ammonium oxalate in the nickel to the composite precipitant is 1.0 to 2.0. 5. The preparation method of fibrous nickelous oxide powder is characterized in that: first, the composite precipitant solution formed by soluble nickel salt solution and oxalic acid or ammonium oxalate or sodium oxalate and ammonia and dispersant PVP is added to the reaction through a feeding device according to stoichiometric in the Ni ²⁺ -NH ₃ -NH ₄ ⁺ -SG ^n- -C ₂ O ₄ ^2- -H ₂ O Composite precipitation transformation is carried out in the system, the temperature is controlled at 55-85°C, the pH is 7.0-9.0, and the initial Ni ²⁺ concentration in the feed liquid is 0.4-1.2mol/l; then the composite precipitate obtained after the reaction is completed is washed, Filtration and drying is the precursor of nickel oxide powder; then the precursor of nickel oxide is placed in an electric furnace regulated by PID, the temperature is controlled at 350-800°C, and thermal decomposition is carried out under the control of an oxidizing atmosphere; The fibrous nickel oxide powder can be obtained by natural cooling of the decomposed nickel oxide powder. SG ^n- in the composite precipitation transformation system represents the acid radical Cl ^- , SO ₄ ^2- , CH ₃ COO ^- or NO ₃ ^- . 6. The method according to claim 5, characterized in that the oxidizing atmosphere is an air atmosphere or an oxygen atmosphere. 7. method according to claim 5 is characterized in that described soluble nickel salt comprises nickel chloride hexahydrate, nickel sulfate hexahydrate, nickel acetate tetrahydrate, nickel nitrate hexahydrate or nickel chloride solution, nickel sulfate solution , Nickel acetate solution, nickel nitrate solution. 8. The method according to claim 5, wherein the stoichiometric stoichiometric coefficient is characterized in that the molar ratio of nickel to oxalic acid or ammonium oxalate in the composite precipitant is 1.0 to 2.0.

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