Method for preparing nanometer tungsten carbide powder by methyl alcohol cracking

A methanol cracking, nano-technology, applied in the direction of carbide, tungsten/molybdenum carbide, etc., can solve the problems of inability to prepare ultra-fine particle WC powder, violent oxidation or explosion, powder fouling, etc., to achieve low cost and high cost. Selective, uniform and stable particle size

Inactive Publication Date: 2005-08-17
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

More than 70 years of production practice in various countries in the world have proved that it is impossible to prepare superfine WC powder with an average WC particle size of less than 0.5 μm by this process.
Moreover, the result of intensified ball milling and crushing will lead to powder fouling, a sharp increase in activity, and the danger of violent oxidation or explosion.

Method used

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  • Method for preparing nanometer tungsten carbide powder by methyl alcohol cracking
  • Method for preparing nanometer tungsten carbide powder by methyl alcohol cracking
  • Method for preparing nanometer tungsten carbide powder by methyl alcohol cracking

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] With an average particle size of 21nm and a specific surface area (BET) of 54m 2 / g WO 3 Powder as raw material. Methanol (CH 3 OH) to the preheating pipeline, keep the preheating temperature at 320°C, methanol is vaporized, and sent to the catalytic cracker, the working temperature is 540°C, methanol is cracked into CO and H 2 , CO and H 2 It is dehydrated by a dryer and molecular sieve, and sent to a tube reactor after drying. The gas flow rate is 200ml / min. Nano WO 3 The loading amount of the powder is 12g / boat, it is kept at 510° C. for 3.5 hours, and it is taken out after fully cooling to obtain nanometer WC powder.

Embodiment 2

[0021] With an average particle size of 21nm and a specific surface area (BET) of 54m 2 / g WO 3 Powder as raw material. Liquid pump transports methanol (CH 3 OH) to the preheating pipeline, methanol is vaporized after preheating at 380°C, and sent to a catalytic cracker, where methanol is cracked into CO and H at 490°C 2 , the cleavage products CO and H 2 After being dehydrated by a dryer and molecular sieve, it is sent to a tubular reactor, and the gas flow rate is controlled at 350ml / min. Nano WO 3 The loading amount of the powder is 25g / boat, and it is kept at 720° C. for 2.5 hours to obtain nanometer WC powder.

Embodiment 3

[0023] With an average particle size of 21nm and a specific surface area (BET) of 54m 2 / g WO 3 Powder as raw material. Methanol (CH 3 OH) to the preheating pipeline, keep the preheating temperature at 410°C, methanol is vaporized, and sent to the catalytic cracker, the working temperature is 430°C, methanol is cracked into CO and H 2 , CO and H 2 It is dehydrated by a dryer and molecular sieve, and sent to a tube reactor after drying. The gas flow rate is controlled at 550ml / min. Nano WO 3 The loading amount of the powder is 33g / boat, and it is incubated at 940° C. for 1.5 hours to obtain nanometer WC powder.

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Abstract

The present invention provides methanol cracking and low temperature vapor carbonizing process of preparing nanometer WC powder. The WO3 powder of average size 21 nm and specific surface area 54 sq m / g as main material and methanol as carbon source are reacted at 450-950 deg.c for 1.5-4 hr in the presence of Co / Fe catalyst to obtain nanometer level WC. Methanol is first made to pass through liquid pump, flow meter and pre-heating pipe at 300-420 deg.c to gasify, and the methanol gas is catalytically cracked in the cracking device at 420-550 deg.c to obtain required reacting gas CO and H2. CO and H2 are made to react with nanometer WO3 powder to produce nanometer level WC. The present invention has the advantages of low cost, high cracking efficiency, and controllable, homogeneous and stable WC granularity.

Description

technical field [0001] The invention belongs to the technical field of nano WC powder preparation, and in particular provides a method for preparing nano WC powder by methanol cracking and low-temperature gas phase carbonization. Background technique [0002] Tungsten carbide (WC) is a kind of refractory metal carbide and an important component of cemented carbide. Cemented carbide is an important industrial material and is known as "the tooth of industry". Nanocrystalline WC-based cemented carbide is a branch of nanomaterials. After the discovery that nanocrystalline ceramic materials have high fracture toughness and ductility while having high hardness, nanoscale WC / Co powder As raw materials, it produces cemented carbide materials with high hardness, high wear resistance and high toughness. [0003] In the past, to prepare WC powder with a particle size of less than 1 μm, it was necessary to prepare fine-grained tungsten powder first, and then undergo a solid-state carb...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B32/949
Inventor 郭志猛卢广锋罗骥吴成义李燏
Owner UNIV OF SCI & TECH BEIJING
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