CN1101289C

CN1101289C - Chemicalpreparing method for nanometre metal iron powder

Info

Publication number: CN1101289C
Application number: CN99110250A
Authority: CN
Inventors: 郑化桂
Original assignee: University of Science and Technology of China USTC
Current assignee: University of Science and Technology of China USTC
Priority date: 1999-07-08
Filing date: 1999-07-08
Publication date: 2003-02-12
Anticipated expiration: 2019-07-08
Also published as: CN1280044A

Abstract

The present invention relates to a method for preparing nanometer metal iron powder. The preparation method is characterized in that molysite is dissolved in water or ethanol, hydrazine hydrate and NaOH are added to the molysite solution for sealing heating to 100 to 250 DEG C in a reaction kettle, the constant temperature is maintained for at least 2 hours, and the nanometer metal iron powder is obtained after cooling, separating, washing and vacuum drying; the mutual compounding and coating of iron, cobalt, nickel, silver (copper), etc. can be carried out. The hydrazine hydrate in the mother solution can be reused or recovered through producing the precipitation of N2H4SO4. The method of the present invention has the advantages of easy obtainment of raw material, low cost, low requirement of device, convenient technology and high efficiency; the raw material can be sufficiently recovered and utilized, the yield of the iron powder reaches more than 95%, and the iron content is as high as more than 97% and the average grain size is below 40 nm.

Description

A kind of chemical preparation process of Nano metal powder

The present invention relates to the method for chemical preparation nanometer iron powder in water solution system or alcohol-aqueous systems.

The metallic iron nano material has a wide range of applications in fields such as catalysis, electromagnetic material, metallurgy, the energy.In the present chemical preparation process, carbonyl process, gas reduction law part harshness, complex process, course of reaction is wayward; In the chemistry of aqueous solution preparation method, more employing be that alkali-metal boron hydride and hypophosphites are made reducing agent, what these class methods obtained is the alloy nano-material that a class contains iron, is not the simple metal ferrum nano material, and with high costs.U.S.'s " material science magazine " (Journal of Materials Science, 32 (1997), 3571-3575) reported at solvent N, make the polymer complex film of 4-vinylpyridine (SVP) or poly-4-vinylpyridine (PVP) iron ion in the dinethylformamide (DMF), with its film that is reduced into the containing metal Fe nanometer particles, be reoxidised into the oxidate magnetic material of iron with hydrazine hydrate.But the film from this nano metallic nickel powder as intermediate product can not get metal nanometer powdered iron, so can not be as the method for preparing metal nanometer powdered iron.So far do not see the report that has in the aqueous solution or successfully prepare nano grade iron powder in alcohol-aqueous systems with the hydrazine hydrate reducing process.Because the difference on the reaction mechanism, continue to use the method for preparing nano Co, Ni powder that inventor's number of patent application 99101538.x invented and to obtain metal nanometer powdered iron.

The objective of the invention is to propose a kind of method that in water solution system or ethanol-aqueous systems, prepares the nano metal iron powder.

The preparation method of this nano metal iron powder, it is characterized in that molysite in the water-soluble or ethanol, add the NaOH that is no less than the hydrazine hydrate of two times of iron ion moles and is no less than three times of iron ion moles, mix, heated sealed is to 100-250 ℃ in reactor, constant temperature is no less than two hours, cooling separates, washing, vacuum drying promptly gets product.

If with the mother liquor behind the above-mentioned separated product, carefully be neutralized to pH 5-6 with sulfuric acid, can get N ₂H ₄H ₂SO ₄Precipitation then can directly reclaim N from the mother liquor behind the above-mentioned separated product ₂H ₄H ₂SO ₄And Na ₂SO ₄

If with isolated N ₂H ₄H ₂SO ₄The NaOH that weight such as adds, same again N ₂H ₄H ₂SO ₄The soluble ferric iron salt of mole 1/6-1/2 is mixed, and reacts in reactor, and reaction condition is the same, can make the nano metal iron powder equally.

Adopt this method,, can control the composition or the form of product easily by temperature, time, medium or the additive of control reaction, or carry out that iron-cobalt-nickel-Yin (copper) waits mutual compound or clad.

The raw material that the inventive method adopted is cheap and easy to get, and equipment needed thereby is simple, and technology is convenient, the efficient height, and raw material can fully be recycled, and adopts the present invention to prepare the iron powder productive rate and can reach more than 95%, and the content of iron can be up to more than 97%, and average grain diameter is below 40nm.

Below be embodiments of the invention.

Embodiment 1:

Take by weighing 6 gram FeCl ₂6H ₂O, be dissolved in 15 milliliters of ethanol after, mix with 8 milliliter of 85% hydrazine hydrate, add 5 gram NaOH again, mix heated sealed in stainless steel cauldron, be warmed up to 180 ℃ earlier, constant temperature half an hour is again in 140 ℃ of constant temperature 2 hours, be cooled to room temperature, drop to normal pressure, open reactor, isolate product, washing, vacuum drying obtains product.

Adopt X-ray diffraction analysis and electron microscopic observation, prove that products therefrom is a α phase Fe powder, its average grain diameter is 35nm;

Adopt leukol phenanthroline colour developing AAS to record the iron powder iron content and be higher than 97%, and learn that its productive rate is 95%.

Embodiment 2:

Take by weighing 6 gram FeCl ₂6H ₂O mixes with 8 milliliter of 85% hydrazine hydrate, adds 10 ml waters, adds 5 gram NaOH again, mixes, and sealing heating in stainless steel cauldron is warming up to 200 ℃, and constant temperature half an hour is again in 120 ℃ of constant temperature 10 hours; Operate with embodiment 1 thereafter.Gained iron powder average grain diameter is below 40nm, and purity reaches 97%, and conversion ratio is more than 95%.

Embodiment 3:

Take by weighing 6 gram FeSO ₄7H ₂O, all the other conditions and operation are with embodiment 2.Gained iron powder average grain diameter 30nm, purity reaches more than 95%.

Embodiment 4:

Earlier with 8 gram FeCl ₃6H ₂O is dissolved in 15 milliliters of ethanol, slowly mixes with 10 milliliter of 85% hydrazine hydrate again, adds 5 gram NaOH, stirs, and reactant is moved in the stainless steel cauldron, is undertaken by embodiment 1 step thereafter, 110 ℃ of constant temperature 4 hours.Obtaining average grain diameter is that 35nm, purity reach the iron powder more than 97%; Productive rate is more than 95%.

Embodiment 5:

Take by weighing 8 gram FeCl ₃6H ₂O adds 10 milliliter of 85% hydrazine hydrate, adds 10 ml waters, stirs, and adds 5 gram NaOH again, below is undertaken by embodiment 2 steps; The iron powder average grain diameter that obtains is at 35nm, and iron content reaches more than 95%, and productive rate reaches more than 95%.

Embodiment 6:

With the mother liquor behind above-mentioned each routine separated product, carefully use H ₂SO ₄Being neutralized to pH is 5-6, gets white N ₂H ₄H ₂SO ₄Precipitation; Sedimentation and filtration is drained, obtained N ₂H ₄H ₂SO ₄So can from the mother liquor behind the above-mentioned separated product, directly reclaim N ₂H ₄H ₂SO ₄And Na ₂SO ₄

N from above-mentioned recovery ₂H ₄H ₂SO ₄In take by weighing 15 the gram N ₂H ₄H ₂SO ₄Precipitation adds 15 gram NaOH, after stirring, with 3.5 gram FeCl ₃6H ₂O mixes, and the sealing heating is warming up to 200 ℃ in stainless steel cauldron, constant temperature half an hour, in 120 ℃ of constant temperature 6 hours, be cooled to room temperature again, drop to normal pressure, open reactor, isolate product, washing, vacuum drying obtains the iron powder of 0.65 gram average grain diameter at 30nm.

Embodiment 7:

Take by weighing 4 gram FeCl ₃6H ₂O is dissolved in 15 milliliters of ethanol, adds 2 milliliter of 85% hydrazine hydrate, add 4 gram NaOH again, mix heated sealed in stainless steel cauldron, be warmed up to 240 ℃ earlier, begin to cool to 180 ℃ after 10 minutes, constant temperature half an hour, in 120 ℃ of constant temperature 6 hours, be cooled to room temperature again, drop to normal pressure, open reactor, isolate product, clean the iron powder that obtains wetting.

The wet iron powder that obtains put into contain 2 gram CoCl ₂6H ₂In 15 milliliters of ethanol-water solutions of O; Take by weighing 4 gram NaOH and be added in 8 milliliter of 50% hydrazine hydrate solution and stir into pasty state, pour into while stirring subsequently in the above-mentioned ethanol-water solution, reacted 15 minutes.Obtain the grey black precipitation after separating mother liquor, this precipitation is washed with water to cleaning solution pH8-9, in stirring, add the silver ammino solution of 2 milliliters of argentiferous 1% (weight), add 5 50% hydrazine hydrate solutions, heating is closely boiled, and the cooling postprecipitation is again through separating, clean, vacuum drying gets product.

Doing X-ray and electronic microscope photos proof product is Fe-Co-Ag compound of uniform size, average grain diameter 20nm.This particle is insoluble in 1: 1 hydrochloric acid, shows that the Ag cladding is on the surface; The content that records iron in this compound powder with leukol phenanthroline colour developing AAS is 61.0%, with raw materials used suitable, illustrates that each step reaction is all very thorough.

Embodiment 8:

The nanometer iron powder 0.50 gram input of getting embodiment 4 is contained 1.0 gram CoSO ₄7H ₂O and 1.0 gram NiSO ₄6H ₂In 15 milliliter of 95% ethanol-water solution of O, the corresponding steps by embodiment 7 goes on later on, and the result obtains 0.88 gram precipitations.The X-ray diffraction analysis is a Fe-Co-Ni-Ag composition metal particle, and it is insoluble in 1: 1 hydrochloric acid, shows the surface of Ag cladding at particle.

Claims

1, a kind of preparation method of nano metal iron powder, it is characterized in that molysite in the water-soluble or ethanol, add the NaOH that is no less than the hydrazine hydrate of two times of iron ion moles and is no less than three times of iron ion moles, mix, heated sealed is to 100-250 ℃ in reactor, constant temperature is no less than two hours, cooling separates, washing, vacuum drying promptly gets product.

2. the preparation method of nanometer iron-cobalt-nickel-Yin composite metal powder, it is characterized in that molysite in the water-soluble or ethanol, add hydrazine hydrate that is no less than two times of iron ion moles and the NaOH that is no less than three times of iron ion moles, mix, heated sealed is to 100-250 ℃ in reactor, constant temperature is no less than two hours, and cooling, separation, washing, vacuum drying get nanometer iron powder; The adding of gained iron powder is contained the solubility cobalt, in the ethanol-water solution of nickel salt, to be no less than three times NaOH by cobalt salt and nickel salt integral molar quantity and stir into pasty state with the hydrazine hydrate solution mixing that is no less than three times by cobalt salt and nickel salt integral molar quantity, pour the above-mentioned solubility cobalt that contains subsequently while stirring into, in the ethanol-water solution of nickel salt, mother liquor is separated in the reaction back, obtain the grey black precipitation, this precipitation is washed with water to cleaning solution pH8-9, the adding argentiferous is no less than the silver ammino solution by iron-cobalt-nickel gross weight 2/1000ths weight in stirring, add a small amount of hydrazine hydrate, heating is closely boiled, the cooling postprecipitation is again through separating, clean, vacuum drying promptly obtains the composition metal particle of nanometer Fe-Co-Ni-Ag.

3. the preparation method of Nano metal powder as claimed in claim 1 or 2 is characterized in that the mother liquor behind the above-mentioned separated product carefully is neutralized to pH 5-6 with sulfuric acid, can get N ₂H ₄H ₂SO ₄Precipitation can directly reclaim N from the mother liquor behind the above-mentioned separated product ₂H ₄H ₂SO ₄And Na ₂SO ₄

4. as the preparation method of Nano metal powder as described in the claim 3, it is characterized in that isolated NaH ₄H ₂SO ₄The NaOH that weight such as adds, same again N ₂H ₄H ₂SO ₄The soluble ferric iron salt of mole 1/6-1/2 is mixed, and heated sealed is to 100-250 ℃ in reactor, and constant temperature is no less than two hours, and cooling separates, washing, and vacuum drying can make the nano metal iron powder equally.