Tungsten Price

2016.11.21-Tungsten Carbide Copper Rod Price

Details: Category: Tungsten Copper Price; Published on Monday, 21 November 2016 15:49; Hits: 1566

As reported by Chinatungsten Online, the current price of 70%WC30%Cu tungsten carbide copper rod of Ø13mmx250mm is $45.50 per piece EXW Xiamen, China on NOV.21, 2016.

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2016.11.21-Tungsten Carbide Ball Price

Details: Category: Tungsten Carbide Price; Published on Monday, 21 November 2016 15:43; Hits: 1280

As reported by Chinatungsten Online, the current price tungsten carbide ball of YG8 for Ø6.0mm of is $0.24 per piece EXW Xiamen, China on NOV.21, 2016.

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Ammonium Metatungstate and Rewriting Paper

Details: Category: Ammonium Metatungstate; Published on Friday, 18 November 2016 15:58; Hits: 2149

Ask: What is the relationship between ammonium metatungstate (AMT) and rewriting paper?

Answer: Nothing direct.

Ask: Then, why you put both of them together?

Answer: Because ammonium metatungstate is the raw material for preparing tungsten dioxide (WO₂), while tungsten dioxide is one of the two material of rewriting paper.

Paper wasting is one of the biggest problems we meet in environment protection currently, we know that, the raw materials of papermaking are plant fiber (such as woods, bamboo, grass), mineral fiber (asbestos, glass fiber, etc), other fiber (nylon, metal wire, etc.), and the polymer material which get from oil cracking. At present, papers used for writing, painting and packing are still manufacturing from plant fiber, which will bring huge threat to environment protection.

Recently, one research team came up with an interesting solution – the rewriting paper, which is using two materials of tungsten dioxide (WO₂) and polyvinyl pyrrolidone; this rewriting paper not only can save water, energy, space, but also can reduce the emissions of greenhouse gas; in addition, this kind of rewriting paper has non-toxic effect, and has been proved to be used for the field of medicine and food. The rewriting paper is through the appearing and fading of blue to realize function of rewriting, if this material is exposed to UV light for more than 30 seconds, the color will automatically become dark blue; while, the blue will fade when exposed in the outdoor for a or two days, or heated; moreover, the addition of polyvinyl pyrrolidone can extend the duration of blue to 10 days, and increase circulation writing to 40 times.

Ammonium metatungstate is a kind of white or yellowish powder with water solubility, and the solubility can reach to 300g/100ml in the water under 20°C, an important tungsten compound in tungsten metallurgy industry. Ammonium metatungstate is mainly used for preparing tungsten oxide, such as tungsten trioxide (WO₃), tungsten dioxide (WO₂), blue tungsten oxide (WO_2.9) and violet tungsten oxide (WO_2.72), tungsten powder, tungsten based carbide; furthermore, AMT is also used in many kinds of petroleum and chemical catalysts, the main raw material of W-based catalyst for oil refineries.

AMT Supplier: Chinatungsten Online ammonium-metatungstate.com	Tel.: 86 592 5129696; Fax: 86 592 5129797;Email:sales@chinatungsten.com
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Ammonium Metatungstate Preparing WO3-Fe2O3/TiO2 Composite Photocatalyst

Details: Category: Ammonium Metatungstate; Published on Thursday, 17 November 2016 16:58; Hits: 2141

WO₃-Fe₂O₃/TiO₂ composite photocatalyst is an inorganic material which can be used in the degradation of pollutants in the environment, the new type of photocatalyst. Traditional photocatalyst is mainly based on titanium dioxide (TiO₂), which has the advantages of chemical stability, high catalytic activity, strong oxidizing power, non-toxic, low cost ect.; however, because the spectral response range of titanium dioxide is really narrow, and thus it can only utilize the ultraviolet light (wavelength less than 387nm), which has become the bottleneck and limited the application range of titanium dioxide. Therefore, the development of photocatalyst which has high activity and can utilize the visible light is of very large economic and practical value.

Research has found that, doping metal ion is an effective way to make TiO₂ showing photocatalytic activity under visible light. Generally believed that the metal ions into the TiO₂ lattice can be introduced impurity levels in the forbidden band, the band gap is reduced, so that the valence band electrons after receiving a large optical excitation wavelength, the first transition to impurity energy level, by once again absorb the energy, the transition from the impurity level to the conduction band, thereby reducing the energy required by stimulated to achieve so that the spectral response range of TiO₂ photocatalytic move to the visible region.

An invention has pointed out a method to prepare WO₃-Fe₂O₃/TiO₂ composite photocatalyst, which bases on the tungsten source of ammonium metatungstate (AMT), with the steps as following:

1. Add water into the ammonium metatungstate solution according to the weight ratio of WO₃: water (1：6〜7);

2. And then add ferric nitrate [Fe(NO₃)₃•9H₂O] according to the weight ration of WO₃: ferric nitrate (5〜7:1 ) to dissolve and get the impregnation liquid;

3. Add TiO₂ powder, which is anatase type with BET specific surface area of 80〜150m²/g, according to the weight ration of WO₃: TiO₂ (1：6〜7), then dry the mixture at 100°C for 4~6 hours;

4. Calcine the mixture at 580°C〜780°C for 5 hours to finally get WO₃-Fe₂O₃/TiO₂ composite photocatalyst.

Compared with the composite materials which dose not dope with metal ions, WO₃-Fe₂O₃/TiO₂ composite photocatalyst is showing a better photocatalytic ability; at the same time, the doping of WO₃ and Fe₂O₃ with specific lattice structure is actually modifying the TiO₂ particle, thus to extended spectral response range of TiO₂, and make it can be widely applied in the fields of environmental purification.

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Ammonium Metatungstate Price on Nov.17th, 2016

Details: Category: Ammonium Metatungstate; Published on Thursday, 17 November 2016 09:36; Hits: 1560

Ammonium metatungstate price with purity over 91.40% from Chinatungsten Online is 35.50 USD/KG, by Chinatungsten FOB Xiamen, Nov.17^th, 2016.

AMT image

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Tungstic Acid Price on Nov.17th, 2016

Details: Category: Tungsten Oxide/Trioxide Price; Published on Thursday, 17 November 2016 09:32; Hits: 2396

Tungstic acid price with purity over 91.00% from Chinatungsten Online is 34.00 USD/KG, by Chinatungsten FOB Xiamen, Nov.17^th, 2016.

yellow tungsten oxide photo

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2016.11.16-Tungsten Carbide Bar Price

Details: Category: Tungsten Carbide Price; Published on Wednesday, 16 November 2016 16:15; Hits: 1255

As reported by Chinatungsten Online, the current price of YG10x tungsten carbide bar for 330mmx25mmx5mm is $43.80 per piece EXW Xiamen, China on NOV.16, 2016.

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2016.11.16-Tungsten Silver Plate Price

Details: Category: Tungsten Copper Price; Published on Wednesday, 16 November 2016 16:10; Hits: 1494

As reported by Chinatungsten Online, the current price of 50%W50%Ag tungsten silver plate of 50mmx20mmx5mm is $90.00 per piece EXW Xiamen, China on NOV.16, 2016.

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Ammonium Metatungstate Preparing Solid Superacid

Details: Category: Ammonium Metatungstate; Published on Tuesday, 15 November 2016 11:10; Hits: 2134

According to the classical definition, a superacid is an acid with an acidity greater than that of 100% pure sulfuric acid, which has a Hammett acidity function (H₀) of −12. According to the modern definition, superacid is a medium in which the chemical potential of the proton is higher than in pure sulfuric acid. The known superacid can be divided into liquid and solid superacid according to the appearance. In petrochemistry, superacidic media are used as catalysts, especially for alkylations. Typical catalysts are sulfated oxides of titanium and zirconium or specially treated alumina or zeolites. The solid acids are used for alkylating benzene with ethylene and propylene as well as difficult acylations, e.g. of chlorobenzene.

In 1998, the presence of supported oxide solid superacid has immediately caused a wave of research in the field of catalyst, which has been reported to have three types, namely WO₃, MoO₃ and B₂O_{3 oxides, with the acidity showing as the following table:}

acidity table of supported oxide solid superacid

The supported oxide solid superacid (WO₃/ ZrO₂) which Arata firstly studied has the acidity lower than that of SO₄^2- / M_xO_y-type solid superacid (SO₄^2- / ZrO₂) with H₀ < -16.0 (while the H₀ of WO₃/ ZrO₂ is lower than 14.5), but its stability in solution and reducing atmosphere and heat is better than that of SO₄^2- / ZrO₂ solid superacid; moreover, it is selectivity for some specific reactions, such as isomerization of high-carbon alkanes, is higher than that of SO₄^2- / M_xO_y catalyst.

The results showed that ammonium metatungstate (AMT) can be used as a tungsten source for the preparation of supported oxide solid superacid (WO₃/ ZrO₂), with the preparation methods of coprecipitation and sol-gel method; both of the two methods are also called as one-step method since it is introducing WO₃at the same time of preparation process, the processes are:

1. Coprecipitation method: Pour the ZrOCl₂ solution into a mixed solution of ammonium metatungstate and ammonia water to conduct coprecipitation, and adjust the final pH value to 9.0, then carry out filtering, washing, drying and calcination to get the final product.

2. Sol-gel method: Add the zirconium n-propoxide into the mixed solution of ethanol and nitric acid containing with ammonium metatungstate to get gelling; remove the ethanol by carbon dioxide supercritical drying method after the obtained gel is aged for 2 hours; and then dry it in vacuum for 3 hours respectively at temperature of 383 K and 523 K, and finally carry out calcination at high temperature.

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2016.11.14-Tungsten Copper Plate Price

Details: Category: Tungsten Copper Price; Published on Monday, 14 November 2016 16:40; Hits: 1510

As reported by Chinatungsten Online, the current price of 30%W70%Cu tungsten copper plate of 300mmx300mmx21mm is $740.00 per piece EXW Xiamen, China on NOV.14, 2016.

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