Produce tungsten powder usually by reducing tungsten oxide which restored ammonium paratungstate or tungsten trioxide by hydrogen. And the reaction is usually carried out in electric tube furnace or rotary furnace. Using hydrogen reaction method to produce tungsten powder there are two important processes, the first is at a temperature of 500℃-700℃ restore tungsten trioxide to tungsten dioxide. And the second is at 700℃-900℃ temperature, tungsten dioxide is reduced to tungsten powder. What’s more tungsten powder good properties (such as purity, particle size, size distribution, etc.) depends on the reduction process, such as the reduction temperature, boat load of tungsten oxide, boat speed, flow rate of hydrogen and hydrogen water content. In addition, using aluminum, calcium, zinc and others to restore tungsten powder also caused a big concern.
Except using hydrogen reaction method to produce tungsten powder, in the early time also using tungsten oxide carbon reduction method to restore tungsten powder which is at the temperature above 1050 ℃. But this method will produce low-purity tungsten powder, so there is less use in industry.

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Tungsten powder restores by hydrogen in four tube muffle furnace where the tungsten oxide as raw material. The particle size of tungsten powder mainly 0.6-3.0um which can be divided into coarse, medium and fine several granularities. Tungsten powder is used to process powder metallurgy of tungsten products and as raw material of tungsten alloy. Tungsten powder can be made into wire, rods, tubes, plates and other processing materials and shaped products. Besides, tungsten powder mixing with other metal powders can be made into a variety of tungsten alloys, such as tungsten and molybdenum alloys, tungsten-rhenium alloy, copper alloy of tungsten and tungsten heavy alloy. And there is another important application of tungsten powder which is used tungsten carbide powder and then uses it to produce carbide tools, such as turning tool, milling cutter, drill and mould.
After many experiments found that the performance of tungsten powder will directly affect the quality of tungsten materials and tungsten powder metallurgy products. Particularly the purity and particle size of tungsten powder affecting products evidently. During the restore reaction, reduction process and raw materials is the main reason for the performance of tungsten powder. Therefore, to produce a good performance of tungsten powder not only to control the reduction process has to choose the good performance of the tungsten oxide raw material.

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Ammonium paratungstate tetrahydrate, APT·4H2O dissolves rather slowly in aqueous ammonia at room temperature. Dissolution at higher temperatures increases the rate of dissolution, but the amount of dissolved tungsten decreases due to the lower solubility of ammonia at higher temperatures which results in a lower PH of the solution. The rate of dissolution was found to be independent of the crystal size. It is therefore concluded that the rate-controlling step occurs in the solution.

Calcination of APT·4H2O in air, nitrogen and hydrogen/nitrogen mixtures, into an X-ray amorphous product, is shown to be one way to improve the dissolution rate and to increase the dissolved amount of APT·4H2O. The highest solubilities can be obtained by calcining APT·4H2O in air or nitrogen at temperatures ranging from 250 to 310°C for approximately 2 h. When the temperature is too low or the residence time is too short some crystalline APT·4H2O will still exist; WO3 is formed when the temperature is too high or the residence time too long.


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Ammonium paratungstate calcined in air change course: T ≥ 240 ℃, and transferred as ammonium metatungstate (AMT).

When the temperature is between 300 ~ 350 ℃, it turns into ammonium tungsten bronze ATB. When the temperature is under 400 ℃, it turns into the hexagonal WO3. When the temperature reaches to 500 ℃, it becomes triclinic crystalline tungsten trioxide.

Ammonium paratungstate purity and crystalline are hereditary. Calcination temperature, speed has a significant impact on the physical and chemical properties of the product.

The higher the calcining temperature, the more coarse particle size of the obtained WO3. Rapid heated will cause the larger specific surface area. Slowly heated which results in the perfect crystalline and smaller specific surface area.


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The alkaline feed of crude sodium tungstate obtained from the caustic fusion of black tungsten ore was neutralized to a pH value near 9 to eliminate Si as routine, then the resulting feed was directly used as the external aqueous phase without eliminating P, As and Mo.

Through a single stage batch liquid membrane process at room temperature for 5 min under optimum operation conditions obtained by an orthogonal test, ammonium paratungstate directly crystallizes in the internal aqueous phase with 99.87% yield and the quality attained was the first grade of a national standard; meanwhile the pH value of the effluents was lowered to 6–7 in itself suitable for direct discharge and without W (VI) lost out of the raffinate. Finally, a continuous counter-current process of a single stage for a pilot plant was proposed.




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Ammonium paratungstate (or APT) is a white crystalline salt of ammonium and tungsten, with the chemical formula (NH₄)₁₀(H₂W₁₂O₄₂)·4H₂O.

Method using ammonia tungstate tungstic acid dissolved, add a boil deionized water. In the stirring, heating by ammonia, Ph value is 8, in the boiling solution by adding acetic acid, and then use the dilute nitric acid. The Ph value is adjusted to 2 ~ 4, continuing heating concentrated to a relative density of 1.5 ~ 2, stop heating, cooling and filtering. The filtrate is added with ethanol. Stir, settlement after filtration, crystal at 80 ℃ drying, pulverizing to obtain the product.

Ammonium paratungstate is used as a source for high-purity tungsten oxides, tungsten metal powders, carbides, or as a laboratory reagent. Also tungsten powder including tungsten trioxide, tungsten blue oxide.




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The crystallization of ammonium paratungstate tetrahydrate, ((NH₄)₁₀OH₂W₁₂O₄₂·4H₂O, APT·4H₂O) from aqueous ammonium tungstate solutions is a key unit operation in current tungsten powder production. Ammonium paratungstate hexahydrate (APT·6H₂O) can form under conditions where APT·4H₂O forms as well. Based on this information it was postulated that APT·6H₂O is metastable. Experiments were carried out to determine whether and under what conditions the hexahydrate is metastable.

It was found that the hexahydrate is metastable at a solution concentration of approximately 300-230 g/kg WO₃ and from approximately 90° to 96°C. APT·6H₂O is not formed when APT·4H₂O seeds are added prior to crystallization. It was found that the recrystallization of APT·6H₂O into APT·4H₂O is prompted by a decreasing water activity in solution during crystallization. The increase in solution temperature during isobaric crystallization also stimulates the recrystallization process. In industrial practice some residual crystals are always present in the crystallizer. Therefore, APT·6H₂O will not form during industrial crystallization.



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Tungsten copper heat sink is a composite of tungsten and copper. The coefficient of thermal expansion (CTE) of the composite can be designed by controlling the content of tungsten, matching that of the materials, such as Ceramics (Al2O3, BeO), Semiconductors (Si), Metals (Kovar), etc. The products are widely application in the fields such as radio frequency, microwave, high power diode packaging and optical communication system.

Tungsten copper heat sink is a heat base which is made of tungsten copper alloy. A heat base is a term for a component or assembly that transfers heat generated within a solid material to a fluid medium, such as air or a liquid. Examples of heat bases are the heat exchangers used in refrigeration and air conditioning systems and the radiator (also a heat exchanger) in a car. Heat bases also help to cool electronic and optoelectronic devices, such as higher-power lasers and light emitting diodes (LEDs).

Advantages: High thermal conductivity, Excellent hermetic, Excellent size control, surface finish and flatness, Semi-finished or finished (Ni/Au plated) products available properties of WCu and MoCu heat materials.

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Copper tungsten rod (WCu) is the composite of tungsten and copper which own excellent performance of tungsten and copper. It is used widely in such industries as engine, electric power, electron, metallurgy, spaceflight and aviation.

Tungsten copper rod is a kind of round rod. Tungsten copper rod is a kind of composite material, which is manufactured by high-purity tungsten powder and high conductivity copper powder with the production process of isostatic pressing, sintering temperature and copper infiltrated

The manufacturing process is as follows: press the refractory metal, sinter the pressed compact at a high temperature, and infiltrate it with copper. All this is done under very closely controlled conditions. The result is a relatively hard material with superior arc and wear resistance, high physical Properties: at elevated temperatures, and good electrical and thermal conductivity.

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Copper tungsten alloy product is a sintered copper tungsten material manufactured by powder metallurgy. It forms dense composite offering hardness, wear resistance and a high softening temperature of tungsten combined with the good electrical conductivity of copper.

Copper tungsten alloy product is a pseudo-alloy of copper and tungsten. As copper and tungsten are not mutually soluble, the material is composed of distinct particles of one metal dispersed in a matrix of the other one. The microstructure is therefore rather a metal matrix composite instead of a true alloy.

The material combines the properties of both metals, resulting in a material that is heat-resistant, ablation-resistant, highly thermally and electrically conductive, and easy to machine.

Parts are made from the CuW alloy by pressing the tungsten particles into a desired shape, sintering the compacted part, then infiltrating with molten copper. Sheets, rods and bars of the alloy are available as well.

Commonly used copper tungsten alloy contains 10–50 wt.% of copper, the remaining portion being mostly tungsten. The typical properties of the alloy depend on its composition. The alloy with less wt.% of copper has higher density, higher hardness and higher resistivity. The typical density of CuW90 alloy, with 10% of copper, is 16.75 g/cm3 and 11.85 g/cm3 for CuW50 alloy. CuW90 has higher hardness and resistivity of 260 HB kgf/mm2 and 6.5 µΩ.cm than CuW50.

Copper tungsten may be used as an electrical contact material. In the most severe applications associated with power generation and transmission the switch may be totally immersed in oil. In these cases there is no advantage in using the tarnish resistant silver-based materials, as oxidation is prevented by the exclusion of air. Copper tungsten contacts are widely used in these cases, the selection of the grade used being dependent on the relative importance of conductivity and arc resistance.

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