CN1907604A

CN1907604A - Direct reduction carbonization manufacture method for tungsten carbide or tungsten carbide-cobalt ultrafine particle powder

Info

Publication number: CN1907604A
Application number: CN 200610032101
Authority: CN
Inventors: 谭小晓; 徐红兵; 谭天翔; 肖明; 谭日善
Original assignee: 谭天翔
Priority date: 2006-08-18
Filing date: 2006-08-18
Publication date: 2007-02-07
Anticipated expiration: 2026-08-18
Also published as: CN100486740C

Abstract

The invention relates to a direct reduction carbonization preparation of tungsten carbide or tungsten carbide-metal cobalt ultra-fine powder, wherein it comprises: (1), preparing materials that mixing the tungsten, or the oxidant of tungsten and cobalt with some carbon to be grinded and packed into graphite container; (2), entering it into furnace to react, that pushing the graphite container into reaction furnace to be reacted at reduction gas; (3), drawing it outside the furnace to be checked that the screening the cooled reacted product to be checked about the total carbon, free carbon and oxygen contents, and watching the granularity distribution; (4) adjusting that when the checked result not meets the demand, micro adjusting the carbon or oxidant and grinding and mixing, feeding the container into furnace, to react at reduction gas; screening, checking and packing after cooling and drawing outside the furnace. The invention has high quality, simple device and high efficiency, while it can be used to product the powders at 1 mum, 0.8 mum, 0.6 mum, 0.4 mum, 0.2 mum and 0.1 mum.

Description

Direct reduction carbonization preparation method of tungsten carbide or tungsten carbide-metal cobalt ultrafine particle powder

Technical Field

The present invention relates to a direct reduction carbonization preparation method of tungsten carbide or tungsten carbide-metal cobalt superfine granule powder.

Background

The existing methods for producing tungsten carbide powder are two-step methods, namely, firstly, reducing tungsten oxide into tungsten powder by using hydrogen, and then carbonizing the tungsten powder and carbon at high temperature into tungsten carbide powder, but the method cannot be used for preparing superfine tungsten carbide powder; as for the production of ultrafine particle tungsten carbide-metal cobalt composite powder, although the practice of NANODYNE company in the United states is first, and the exploration of Wuhan university of science and technology in China is later, the WC-Co molecular level mixing of the former can not form the complete coating effect of cobalt on tungsten carbide powder when manufacturing hard alloy, and consequently, the crystal grain grows up and the performance is reduced, while the latter is too complicated in process and has a distance from practical popularization and application.

Disclosure of Invention

The invention aims to make up the defects of the prior art and provides a preparation method of tungsten carbide or tungsten carbide-metal cobalt ultrafineparticle powder, namely a direct reduction carbonization method by using carbon.

The invention relates to a direct reduction carbonization preparation method of tungsten carbide or tungsten carbide-metal cobalt ultrafine particle powder, which is characterized by sequentially comprising the following steps:

(1) preparing materials, namely taking a certain amount of tungsten oxide or tungsten and cobalt oxide, wherein the purity of the tungsten oxide or tungsten and cobalt oxide is 99%, adding a carbon source according to 70-125% of theoretical carbon content required by tungsten carbide or tungsten carbide-metal cobalt generated by reaction with the tungsten oxide or tungsten and cobalt oxide, and filling the mixture into a graphite boat after ball milling for 2 hours by using a ball mill;

(2) performing a furnace reaction, namely pushing the graphite boat filled with the mixture into a high-temperature molybdenum wire tube furnace or a single-tube push-boat high-temperature furnace at 900-1850 ℃, and reacting for 0.5-6 hours in a reducing atmosphere;

(3) the detection of discharging the furnace is that the reactant is cooled for 0.5 to 1 hour in a cooling zone of the furnace, the reactant is discharged from the furnace and passes through a 80-mesh sieve to remove part of mechanical impurities, and then the total carbon, the free carbon and the oxygen content in the reactant are detected, wherein the total carbon is 6.12 to 6.25 percent (weight percentage, the same applies below), the free carbon is 0.1 to 0.2 percent, and the oxygen content is less than or equal to 0.25 percent;

(4) adjusting, when the prepared product is tungsten carbide powder and the detection result does not meet the requirement, finely adjusting the product to be matched with carbon or tungsten oxide, when the product is tungsten carbide-metalcobalt powder, additionally matching cobalt oxide with the amount of metal cobalt required by the alloy process or tungsten oxide required by the alloy process in the fine adjustment, or additionally matching reduced cobalt oxide with the amount of metal cobalt and reduced tungsten oxide with the amount of carbon required by tungsten carbide, ball-milling and mixing the adjusted material for 0.5-2 hours, reacting in a high-temperature molybdenum wire tube furnace at 900-1850 ℃ for 0.5-6 hours under the protection of gas, cooling, ball-milling, sieving, detecting and packaging.

Specifically, in the raw materials, the tungsten oxide can be one or two of tungsten trioxide, blue tungsten oxide, purple tungsten oxide, ammonium paratungstate and ammonium metatungstate, the cobalt oxide is cobaltosic oxide, and the carbon source can be 1-2 selected from graphite powder, metallurgical carbon black and polypropylene wax; and the reducing atmosphere of the furnace entering reaction is 1-2 of hydrogen, nitrogen, argon and carbon monoxide.

The reaction process is carried out according to the following equation

Detailed Description

The first embodiment is as follows: weighing tungsten trioxide (with the purity of 99%) and graphite powder according to the mass ratio of 20: 5, ball-milling and mixing for 2 hours, loading in a graphite boat, and putting in a container of H₂Pushing the mixture into a 1300 ℃ single-tube push-boat high-temperature furnace under the protection atmosphere for reaction for 1 hour, cooling the mixture in a cooling zone of the furnace for 1 hour until the temperature of reactants is close to room temperature, taking the mixture out of the furnace and passing through a 80-mesh sieve, analyzing the content of total carbon, free carbon and oxygen in the reactants, finely adjusting carbon supplement or tungsten trioxide if necessary, ball-milling and mixing the mixture for 1 to 2 hours, loading the mixture into a graphite boat, and putting the graphite boat in a high-temperature molybdenum wire tube furnace under the protection of hydrogen in a 1300 ℃ highReacting for 5 hours at the temperature of furnace, cooling and discharging the materials along with the furnace, ball-milling and sieving, and analyzing and detecting to obtain a product with the average particle size of about 0.4 mu m and total carbon6.12 to 6.25 percent, 0.1 to 0.2 percent of free carbon and less than or equal to 0.25 percent of oxygen content (all weight percentages); after the average particle size of the product is measured by a Beijing SSA-3600 specific surface instrument, the average particle size and the particle morphology are observed by a scanning electron microscope, and the result completely meets the requirements of single phase and single crystal.

Example two: weighing tungsten trioxide, cobaltosic oxide and metallurgical carbon black according to the mass ratio of 20: 12: 6, and then sequentially carrying out the steps as described in example one. The furnace temperature in the furnace reaction is 1300 ℃, the hydrogen is used for reducing atmosphere protection, the reaction time is 2 hours, and the cooling time in the furnace is 1 hour; after detection, finely adjusting the materials to be matched with carbon and cobaltosic oxide, carrying out ball milling and mixing for 2 hours, reacting for 2 hours in a 1300 ℃ high-temperature molybdenum wire tubular furnace under the protection of hydrogen, cooling, discharging, carrying out ball milling, and sieving with a 80-mesh sieve, wherein the detection result completely meets the requirement, theaverage particle size is 0.4 mu m, and the tungsten carbide-cobalt composite powder is superfine tungsten carbide-cobalt metal composite powder.

In conclusion, the method has the advantages of short process flow, good product quality, simple equipment, high efficiency, low power consumption, water consumption and hydrogen consumption and the like, can be used for producing powder with the particle size of 1 micron, 0.8 micron, 0.6 micron, 0.4 micron, 0.2 micron, 0.1 micron or even finer, and is very beneficial to the hard alloy industry.

Claims

1. The direct reduction carbonization preparation method of the tungsten carbide or tungsten carbide-metal cobalt superfine particle powder is characterized by sequentially comprising the following steps:

(1) preparing materials, namely taking a certain amount of tungsten oxide or tungsten-cobalt oxide with the purity of 99 percent, adding a carbon source according to 70-125 percent of theoretical carbon content required by tungsten carbide or tungsten carbide-metal cobalt generated by reaction with the tungsten oxide or the tungsten-cobalt oxide, and filling the mixture into a graphite boat after ball milling for 2 hours by using a ball mill;

(3) the detection of discharging the furnace is that the reactant is cooled for 0.5 to 1 hour in a cooling zone of the furnace, the reactant is discharged from the furnace and sieved by a 80-mesh sieve to remove part of mechanical impurities, and then the total carbon, the free carbon and the oxygen content of the reactant are detected, wherein the total carbon is 6.12 to 6.25 percent (weight percentage, the same below), the free carbon is 0.1 to 0.2 percent, and the oxygen content is less than or equal to 0.25 percent;

(4) adjusting, when the prepared product is tungsten carbide powder and the detection result does not meet the requirement, finely adjusting the product to be matched with carbon or tungsten oxide, when the product is tungsten carbide-metal cobalt powder, additionally matching cobalt oxide with the amount of metal cobalt required by the alloy process or tungsten oxide required by the alloy process in the fine adjustment, or additionally matching reduced cobalt oxide with the amount of metal cobalt and reduced tungsten oxide with the amount of carbon required by tungsten carbide, ball-milling and mixing the adjusted material for 0.5-2 hours, reacting in a high-temperature molybdenum wire tube furnace at 900-1850 ℃ for 0.5-6 hours under the protection of hydrogen, cooling, and then ball-milling, sieving, detecting and packaging.

2. The method for producing ultrafine particles of tungsten carbide or tungsten carbide-metal cobalt by direct reduction carbonization according to claim 1, wherein the tungsten oxide in the raw material is one or two of tungsten trioxide, blue tungsten oxide, purple tungsten oxide, ammonium paratungstate and ammonium metatungstate, the cobalt oxide is tricobalt tetraoxide, and the carbon source is 1 to 2 selected from graphite powder, activated gold carbon ink and polypropylene wax.

3. The method for producing ultrafine particles of tungsten carbide or tungsten carbide-metallic cobalt by direct reduction carbonization according to claim 1 or 2, wherein the reducing atmosphere in the charging reaction is 1 to 2 kinds of hydrogen, nitrogen, argon, and carbon monoxide.