CN1126625C - Preparation process of superfine carbide powder by direct reduction carbonization in pipe furnace - Google Patents
Preparation process of superfine carbide powder by direct reduction carbonization in pipe furnace Download PDFInfo
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- CN1126625C CN1126625C CN 00107259 CN00107259A CN1126625C CN 1126625 C CN1126625 C CN 1126625C CN 00107259 CN00107259 CN 00107259 CN 00107259 A CN00107259 A CN 00107259A CN 1126625 C CN1126625 C CN 1126625C
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Abstract
The present invention provides a technology for preparing WC or compound alloy powder used for nanometer-scale superfine particle hard alloy by direct reduction and carbonation in a general tubular furnace. Nanometer-scale superfine WO3 or WO3-Nio-Feo produced by a mist-spray thermal conversion method is used as raw material and mixed with a certain amount of black carbon powder. Moreover, the mixture is arranged in the ordinary tubular furnace. Firstly, nitrogen gas is used as protective gas, H2 is then introduced for preliminary reduction under the temperature of 600 to 800 DEG C, and the nitrogen gas is turned off. The temperature of 800 to 1200 DEG C is preserved for 40 to 120 minutes, and then, powder with the average crystal granularity of at most 150 nanometers can be obtained. The method has the advantages of simple technological processes, easy control of carbon content, stable powder property and small crystal granularity.
Description
The invention belongs to the preparation technology of nano level superfine particle Wimet with the WC powder, also can be used to prepare WC-Ni-Fe simultaneously is the composite alloy powder.
The range of application of Wimet is very extensive, and in recent years owing to world's cobalt ore resource exhaustion, novel tungsten nickel is, the W-Ni-Fe alloy Wimet is come out one after another, and developed rapidly.Yet these alloys still can not satisfy the modern age high-tech to the requirement of Wimet, thus beautiful, day, the English various countries all drop into a large amount of manpower and materials, develop the production technology of ultra-fine grain Wimet rapidly.
Prepared sizes were less than the Wimet of 1 μ m in the past, and preparation fine particle tungsten powder is made fine particle (WC) tungsten carbide powder through carbonization then earlier, through the long-time ball mill crushing of strengthening, can obtain the Wimet of mean particle size less than 1 μ m again.Seven during the last ten years the production practice of countries in the world prove, can't prepare the ultrafine gain size of WC mean grain size with this technology less than 0.5 μ m.And the result of reinforcement ball mill crushing, can cause dirtyization of powder, the active danger that increases severely and can produce vigorous oxidation or blast again.
Through international online retrieval DAILOG system, 2,8,32,38,200,350,351,344,347 documents check in six pieces of general pertinent literatures altogether, two pieces is patent documentation, according to aggregate data as can be seen, L.E.Mc.Candollish of U.S. Rugers university in 1991 etc. (international patent application publication W091107244) and Chinese patent application prospectus CN1086752A in 1994 have all delivered the technology of preparing for preparing the ultra-fine grain cemented carbide powder with fluidized bed plant.Chinese Zigong Hard Alloy Foundry had been delivered with vapour deposition (CVD) method in 1997, and the preparation mean grain size is less than the preparation method of 0.5 μ m Wimet, and above method all belongs to preparation WC-Co series hard metal.Aforesaid method all has shortcoming separately, is to prepare WC-Ni-Fe series hard metal composite powder as the shortcoming of fluidized bed process, and the operating air consumption is very big.Dust removal installation is huge, casting yield is low, the heat energy utilization rate is low, and has adopted (second diamino) deleterious solvent in the formulations prepared from solutions process, and environment is had pollution.
Vapour deposition process (CVD) can not prepare WC-Ni-Fe series hard metal composite powder, and yields poorly, and the cost height contains corrosive gases in the waste gas, and continuous production in enormous quantities is difficulty.
The purpose of this invention is to provide a kind of in conventional tube furnace reduction and carbonization directly prepare the preparation technology of WC powder or WC-Ni-Fe series nanometer grade ultra-fine grain hard alloy compound powder.Can also prepare simultaneously WC-Ni system in this way, WC-Ni-Fe system, WC-Co series nanometer grade ultra-fine grain hard alloy compound powder.
Formation of the present invention mainly is the technology that reduction and carbonization prepares nano level superfine crystal grain wolfram varbide one nickel one iron series nanometer grade hard alloy compound powder in tube furnace.
Technology of the present invention is down directly to reduce WO with common tube furnace at low temperature 800-1200 ℃
3-FeO-NiO prepares the method for nano level superfine particle WC-Ni-Fe composite powder.Nano level superfine composite oxide power through the preparation of ullrasonic spraying thermal conversion method is placed the tube furnace internal heating through joining the carbon mixing, and successively pass to N
2And H
2Gas is at N
2The oxide compound of tungsten directly contacts with solid carbon and is reduced into WO successively under the atmosphere of gas
2.90→ WO
2.72→ WO
2→ W.Later stage is at H
2W powder that just has been reduced under the atmosphere and C reaction generate WC, and its reduction-carbonization mechanism was undertaken by following two steps and method:
A. median size≤50nm (WO
3-NiO-FeO) powder with after ultra-fine carbon black powder mixes, passes to N at 600-800 ℃ in the 200-250g/Kg ratio
2Gas, this moment, various oxide powders were reduced successively by carbon.
The Tungsten oxide 99.999 reduction reaction:
B. in 800-1200 ℃ of interval, close N
2Gas changes into and feeds H
2Gas, reaction this moment is mainly carbon and at first generates hydrocarbon polymer with hydrogen, decomposes subsequently again, and its carburizing reagent is as follows:
The reduction and carbonization reaction reduced equation of above-mentioned Tungsten oxide 99.999 is:
The WO that the present invention uses
3-NiO-FeO powder is the nano level superfine oxide powder that adopts ullrasonic spraying thermal conversion method to be produced, and it is the ultra-fine carbon black powder of 0.05-1 μ m that carbon black powders need adopt particle diameter, and general fine particle 5-10 μ m carbon black powder also can use after ball milling 24-72 hour.Its furnace tube material of tubular type reduction furnace that adopts is made by common heat resisting pipe; The furnace binding of reduction and carbonization stove can adopt logical N
2Gas or logical H
2The structure of two sections bodies of heater of gas serial connection, or be divided into two independently body of heater use respectively.
The oxide compound that the invention has the advantages that tungsten is at N
2Be reduced under the gas shiled and be WO
2.90, WO
2.72Or WO
2During particle,, kept nano-scale particle size because of having avoided the volatilization growth process, in addition the carbonization temperature of tungsten only up to 1200 ℃ well below conventional carbonization temperature 1600-1800 ℃, prevented that the gathering of WC particle from growing up and complicated carbide phase (M
6C, M
12C) formation.
Carbon and hydrogen decompose after generating hydrocarbon polymer again, and it is very little to decompose the carbon black particle that comes out, and has very high activity, help the carbonization of tungsten, and to the tungsten powder internal diffusion, the buffer action of carbon black can also avoid the tungsten powder gathering to grow up simultaneously, and the indirect tungsten carbide particle that also prevented is grown up.Thereby directly carbonization technique is simple, and reliable, production cost is low, is easy to apply.
The present invention is further described below in conjunction with accompanying drawing:
Fig. 1 is the technical process that direct reduction and carbonization of the present invention prepares tungsten-carbide powder, wherein
The 1st, ultra-fine WO
3Or WO
3-NiO-FeO composite oxide powder, the 2nd, join carbon, the 3rd, wet-milling mixes, and the 4th, the carbon black powder ball milling, the 5th, sieve, the 6th, oven dry, the 7th, sieve, the 8th, oven dry, the 9th, carbonization, the 10th, WC or WC-Ni-Fe composite alloy powder.
Fig. 2 is principle of work of the present invention and equipment connection figure.The 11st, nitrogen, the 12nd, hydrogen, the 13rd, hydrogen ignitron, the 14th, tubular type reduction furnace furnace shell, the 15th, cold zone thermopair, the 16th, high-temperature zone thermopair, the 17th, high temperature steel boiler tube, the 18th, water jacket, the 19th, fire door, the 20th, high temperature steel boat, 21 grates.
4 is the carbon black powder wet-milling among technological process Fig. 1, and the time is 24-72 hour, and 5 are the carbon black powder screening, and 6 are the carbon black powder oven dry. Carry out 2 after the quality of oxidate powder 1 is calculated by the reduction and carbonization reaction equation and join carbon. The mixed powder of allocating carbon into is carried out 3 wet-millings, mix after 24-72 hour, the mixed powder that wet-milling is mixed carries out 7 and sieves in (320 order), carries out carbonization through putting into tube furnace 9 after 8 oven dry again. Led to first in the past N at 600-800 ℃2Gas, 800-1200 ℃ passes into H2Gas is incubated after 20-60 minute cooling, has namely obtained nano level superfine (powder of average crystal grain≤150nm), or (WC-Ni-Fe) complex alloy powder 10.
Embodiment 1
Preparation WC-8% (Ni-Fe) nano level superfine particle hard alloy compound powder.Should follow these steps to finish:
1. take by weighing the nano level (WO of spraying thermal conversion method preparation
3-NiO-FeO) composite oxide power 2kg, alloying element content is WC-8% (Ni-Fe) massfraction behind its reduction and carbonization, puts into wet-milling blender 2.
2. get 1kg carbon black powder (granularity 5 μ m) and put into wet wheeling machine 4 wet-millings after 48 hours, cross 320 mesh sieves 5 drying machine 6 dry for standby again.Take by weighing carbon black powder, its add-on m calculates by following formula:
m＝m
1+m
2+m
3
231.8 48/2
2000×92％ m
1
74.7 12/22000×8％×70％ m
2
72 12/22000×8％×30％ m
3 
Total mixed carbon comtent m=m
1+ m
2+ m
3=(190.5+9+4)=203.5 (gram).
All by theoretical half calculating that participates in the carbon amount of reaction, this is because also have H in reduction process when mixed carbon comtent calculates
2Participate in reduction and these data through test of many times and definite.
If when only preparing WC powder with technology of the present invention, mixed carbon comtent only calculates m
1Get final product.
To join carbon and mix, dry the mixed powder after 8, put into high temperature steel boat 20, boat charge 250 gram/boats, feed nitrogen (4 liters/minute) earlier, boiler tube Φ 70mm, 870 ± 20 ℃ of insulations of furnace temperature changed feeding hydrogen after 50 minutes, flow is (4 liters/minute), and furnace temperature is risen to 1090 ± 10 ℃ of insulations 45 minutes.Then boat is pushed in the watercooling jacket 18, powder is come out of the stove after cooling, closes to criticize through ball milling to obtain up-to-standard WC-8% (Ni-Fe) (massfraction) powdered alloy.
Prepare the WC-Ni-Fe powdered alloy with aforesaid method, its average particle size≤150nm.
Embodiment 2
Preparation WC-10% (Ni-Fe) nano level superfine particle hard alloy compound powder.Should follow these steps to finish:
Take by weighing the nano level (WO of spraying thermal conversion method preparation respectively
3-NiO-FeO) composite oxide powder 1000 restrains, and alloying element content is WC-10% (Ni-Fe) behind its reduction and carbonization
Take by weighing through the wet wheeling machine wet-milling after 36 hours, cross the carbon black powder m gram of 320 mesh sieves, m calculates by following formula:
m＝m
1+m
2+m
3
Total mixed carbon comtent=m
1+ m
2+ m
3=(93.2+5.6+2.5)=101.3 (gram)
Above-mentioned two kinds of powder are put into wet-milling meal mixer 2, mix after 72 hours, mixed powder after 8 oven dry of drying machine, put into high temperature steel boat 20, boat charge 300 gram/boats, feed 5 liters/minute of nitrogen, boiler tube diameter of phi 70mm, 800 ± 20 ℃ of furnace temperature were incubated after 30 minutes, change feeding hydrogen (flow is 5 liters/minute) furnace temperature is risen to 1060 ℃ ± 10 ℃, be incubated after 60 minutes, boat is pushed in the watercooling jacket 18, and powder is come out of the stove after cooling, closes to criticize through ball milling to obtain WC-10% (Fe-Ni) alloy powder.
With above-mentioned cemented carbide powder through high pressure soft mode press forming, in vacuum, press sintering again after, WC mean particle size≤500nm in the alloy, bending strength 〉=3000MPa, hardness HRA 〉=90.5～92.
Claims (3)
1. one kind directly prepares the method for nano level superfine crystal grain Wimet (WC-Ni-Fe) composite powder with conventional tube furnace reduction and carbonization, it is characterized in that: directly reduce WO with common tube furnace at low temperatures
3-FeO-NiO prepares the method for nano level superfine particle WC-Ni-Fe composite powder, at first the (WO of median size≤50nm
3-after NiO-FeO) powder is pressed the 100-101.7g/Kg proportioning and ultra-fine carbon black powder is mixed, placing conventional tube furnace, the reduction protection gas that need add 800-870 ℃ of temperature stage is nitrogen, is incubated 30 minutes～1 hour and carries out first stage of reduction; Pass to hydrogen heat-insulation 1060-1200 ℃ of temperature stage again and carried out the subordinate phase reduction and carbonization in 45 minutes～1 hour, can finally obtain up-to-standard WC-Ni-Fe composite alloy powder.
2. method according to claim 1 is characterized in that: the WO of use
3-NiO-FeO powder is the nano level superfine oxide powder that adopts ullrasonic spraying thermal conversion method to be produced, and adopting the carbon black powders particle diameter is the ultra-fine carbon black powder of 0.05-1 μ m, or adopts the general fine particle 5-10 μ m carbon black powder through ball milling 24-72 hour.
3. method according to claim 1 and 2 is characterized in that: its furnace tube material of tubular type reduction furnace of employing is made by common heat resisting pipe; The furnace binding of reduction and carbonization stove adopts logical N
2Gas or logical H
2The structure of two sections bodies of heater of gas serial connection, or be divided into two independently body of heater use respectively.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 00107259 CN1126625C (en) | 2000-04-30 | 2000-04-30 | Preparation process of superfine carbide powder by direct reduction carbonization in pipe furnace |
Applications Claiming Priority (1)
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|---|---|---|---|
| CN 00107259 CN1126625C (en) | 2000-04-30 | 2000-04-30 | Preparation process of superfine carbide powder by direct reduction carbonization in pipe furnace |
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|---|---|
| CN1321558A CN1321558A (en) | 2001-11-14 |
| CN1126625C true CN1126625C (en) | 2003-11-05 |
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Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1302883C (en) * | 2005-05-04 | 2007-03-07 | 浙江天石粉末冶金有限公司 | Method and equipment for mfg. alloy powder contg. nanometer crystal particle WC-Co-VC-Cr3-C2 |
| CN100357050C (en) * | 2005-09-12 | 2007-12-26 | 北京科技大学 | Ventilated forced drainage type nano tungsten powder reducing furnace for industrial use |
| CN103302309B (en) * | 2013-06-17 | 2016-04-20 | 南昌大学 | A kind of preparation method of nanometer tungsten carbide |
| CN105043102B (en) * | 2015-04-16 | 2017-02-22 | 重庆大学 | Novel method for reducing sinter using hydrogen |
| CN105689699B (en) * | 2016-01-27 | 2018-01-23 | 西安建筑科技大学 | A kind of process units and technique for producing hypoxemia dusty material |
| CN107116227B (en) * | 2017-04-25 | 2018-11-30 | 北京工业大学 | A kind of preparation method of ultrafine WC-Ni composite powder |
| CN107089662B (en) * | 2017-06-16 | 2019-05-31 | 重庆大学 | A kind of method that CH4 reduction and carbonization WO3 prepares WC powder |
| CN108409327A (en) * | 2018-03-23 | 2018-08-17 | 河南工业大学 | A kind of method of carbothermic method synthesis WC base nano composite powders |
| CN114309608B (en) * | 2021-12-29 | 2022-10-28 | 西南大学 | Tube furnace and method for releasing green compact forming agent from tube furnace |
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2000
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