A method for preparing superfine tungsten carbide powder from arsenic-containing ammonium metatungstate

Abstract

A method for preparing ultrafine tungsten carbide powder from arsenic-containing ammonium metatungstate comprises steps as follows: ammonium metatungstate is added to a nitric acid solution of arsenic, and the content of arsenic in raw materials is 0.01wt%-5wt%; the mixture is uniformly stirred, dried and ground, and ammonium metatungstate-arsenic precursor composite powder is prepared; the precursor composite powder is put in a chamber electric furnace, calcined at the temperature of 580 DEG C-620 DEG C at the air atmosphere and subjected to heat preservation for 2-4 hours, and yellow tungsten trioxide powder is prepared; the yellow tungsten trioxide powder and carbon black stock are taken as reactants, the mass ratio of carbon black to tungsten trioxide is (0.20:1)-(0.22:1), a carbonization reaction is performed under the condition of argon at the temperature of 1,380 DEG C-1,420 DEG C for 1-3 hours, and the ultrafine tungsten carbide powder is prepared. The process is simple, the production cost is low, the method is suitable for volume production of the ultrafine tungsten carbide powder in a factory, the combined-carbon content of the prepared tungsten carbide powder is high, the size distribution is uniform, the dispersity is good, and the particle sizes of the ultrafine tungsten carbide powder range from 200 nm to 300 nm.

Description

technical field [0001] The invention belongs to the research field of tungsten carbide-based cemented carbide. Background technique [0002] Cemented carbide is commonly known as "industrial teeth". Ultrafine cemented carbide is known as "three high alloys" because of its high toughness, high strength and high hardness, which effectively solves the contradiction between the strength and hardness of traditional cemented carbide. However, the quality of WC powder directly affects the performance of cemented carbide products. In order to obtain high-performance ultrafine WC-Co cemented carbide, it is necessary to control the grain size of WC. Therefore, the preparation of ultrafine tungsten carbide powder with good dispersion and uniform particle size distribution is the key technology for the preparation of ultrafine grain WC-Co cemented carbide. [0003] At present, the preparation of ultrafine tungsten carbide powder mainly includes traditional tungsten oxide hydrogen redu...

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Problems solved by technology

The plasma chemical synthesis method requires special tooling and equipment, and the process control is difficult and the production cost is high, which is not conducive to mass production; the mechanical alloying method, long-term ball milling will increase the oxygen content and impurity content of tungsten carbide, and can only be used in small batches Production, it is difficult to achieve large-scale production; in the traditional tungsten oxide hydrogen reduction-carbonization method, the tungsten powder is sintered and thickened during the carbonization process, and coarse aggregates are formed, so that the particle size, uniformity and dispersion of the tungsten carbide powder are difficult to achieve Requirements; tungsten oxide direct reduction carbonization method usually adopts lower carbonization temperature, low carbonization temperature causes incomplete carbonization, W 2 The content of C and free carbon is high, so it is difficult to achieve qualified carbonization at one time. Although the carbonization can be completed by increasing the carbonization temperature, the high carbonization temperature will cause the WC particles to grow rapidly

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