2016.11.16-Tungsten Carbide Bar Price
- Category: Tungsten Carbide Price
- Published on 16 November 2016
- Hits: 1289
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.
| Tungsten Carbide Supplier: Chinatungsten Online tungsten-carbide.com.cn |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News&Tungsten Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
2016.11.16-Tungsten Silver Plate Price
- Category: Tungsten Copper Price
- Published on 16 November 2016
- Hits: 1533
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.
| Tungsten Copper Supplier: Chinatungsten Online tungsten-copper.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News & Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
Ammonium Metatungstate Preparing Solid Superacid
- Category: Ammonium Metatungstate
- Published on 15 November 2016
- Hits: 2190
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 B2O3 oxides, with the acidity showing as the following table:
The supported oxide solid superacid (WO3/ ZrO2) which Arata firstly studied has the acidity lower than that of SO42- / MxOy-type solid superacid (SO42- / 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 SO42- / ZrO2 solid superacid; moreover, it is selectivity for some specific reactions, such as isomerization of high-carbon alkanes, is higher than that of SO42- / MxOy 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 WO3 at 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.
| AMT Supplier: Chinatungsten Online ammonium-metatungstate.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News&Tungsten Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
2016.11.14-Tungsten Copper Plate Price
- Category: Tungsten Copper Price
- Published on 14 November 2016
- Hits: 1556
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.
| Tungsten Copper Supplier: Chinatungsten Online tungsten-copper.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News & Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
2016.11.14-Tungsten Carbide Rod Price
- Category: Tungsten Carbide Price
- Published on 14 November 2016
- Hits: 1580
As reported by Chinatungsten Online, the current price of YG10x tungsten carbide rod for Ø5mmx50mm is $1.10 per piece EXW Xiamen, China on NOV.14, 2016.
| Tungsten Carbide Supplier: Chinatungsten Online tungsten-carbide.com.cn |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News&Tungsten Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
2016.11.11-Tungsten Carbide Rod Price
- Category: Tungsten Carbide Price
- Published on 11 November 2016
- Hits: 1543
As reported by Chinatungsten Online, the current price of YG10 tungsten carbide rod for Ø6mmx330mm is $8.50 per piece EXW Xiamen, China on NOV.11, 2016.
| Tungsten Carbide Supplier: Chinatungsten Online tungsten-carbide.com.cn |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News&Tungsten Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
2016.11.11-Tungsten Copper Rod Price
- Category: Tungsten Copper Price
- Published on 11 November 2016
- Hits: 1589
As reported by Chinatungsten Online, the current price of 75%W25%Cu tungsten copper rod of Ø7mmx150mm is $5.20 per piece EXW Xiamen, China on NOV.11, 2016.
| Tungsten Copper Supplier: Chinatungsten Online tungsten-copper.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News & Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
Ammonium Metatungstate Preparing Ammonium Dithiotungstate
- Category: Ammonium Metatungstate
- Published on 11 November 2016
- Hits: 2194
Ammonium metatungstate (AMT) is an important intermediate compound in tungsten metallurgy industry, which is mainly used for manufacturing tungsten oxide, tungsten powder, tungsten wire and other tungsten compound, also, it is used in catalyst of petrochemical industry. Researches have indicated that ammonium metatungstate and ammonium sulfide solution can be used for preparing ammonium dithiotungstate under some specific environment.
There are two methods of ammonium metatungstate preparing ammonium dithiotungstate, as following:
The first method:
1. Dissolve ammonium metatungstate in the deionized water with stirring;
2. Add ammonia water and stir for 20 minutes to speed up the reaction speed under the temperature of 60°C, at this time, the pH value of reaction system may be 9;
3. Add ammonium sulfide solution and stir for 30 minutes under 60°C, then carry out vacuum filtration until the reaction is stop to remove a small amount of blue precipitation which generated during the reaction process;
4. Stand the filtrate for 24 hours under 0°C to get yellow crystal;
5. Carry out vacuum filtration and the precipitation is washed respectively with deionized water and anhydrous ethanol for three times, and finally we get the ammonium dithiotungstate crystal after drying, with the yield of 45%.
The second method:
1. Place the 5g of industrial grade ammonium tungstate which contains 83% of tungsten trioxide into conical beaker, and add 8 wt% of ammonium sulfide solution 35ml slowly, at this time the color of the solution will slowly turns from blue to light yellow;
2. Stir for 30 minute at room temperature after all the ammonium sulfide solution is poured into the conical beaker, and then stand the reactant solution for 12 hours to generate yellow crystal;
3. Precipitate, and wash the precipitation respectively with deionized water and anhydrous ethanol for three times, dry at room temperature in vacuum environment to finally get ammonium dithiotungstate crystal, the yield is 93% in accordance with tungsten content.
Ammonium dithiotungstate [(NH4)2WO2S2] is an important class of thiometal ammonium salt, and the decomposition products include {WOS2}, vulcanization intermediate of tungsten oxide. Studies have found that the thermal decomposition of ammonium dithiotungstate crystal under the atmosphere of hydrogen is mainly occurred among 160～450℃, which firstly transfers to {WOS2} and then to tungsten disulfide.
| AMT Supplier: Chinatungsten Online ammonium-metatungstate.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News&Tungsten Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
Ammonium Metatungstate Preparing Thermal Insulation Additive
- Category: Ammonium Metatungstate
- Published on 09 November 2016
- Hits: 2274
Many metal oxides and some tungstate have the electrical conductivity and thermal insulation properties, and can be used as infrared shielding material. By heating the mixture solution of ammonium metatungstate (AMT) and alkali carbonate to 80°C, it can prepare some kind of tungsten oxide and tungsten bronze, and all these resulting substances can be used as the raw material of light transmission conductive films with infrared shielding property.
Thermal insulation additive is a kind of material which can stop the thermal conduction during heat transfer. Thermal insulation is the reduction of heat transfer (the transfer of thermal energy between objects of differing temperature) between objects in thermal contact or in range of radiative influence. Thermal insulation can be achieved with specially engineered methods or processes, as well as with suitable object shapes and materials. The insulating capability of a material is measured with thermal conductivity (k). Low thermal conductivity is equivalent to high insulating capability (R-value). In thermal engineering, other important properties of insulating materials are product density (ρ) and specific heat capacity (c).
Ammonium metatungstate to prepare thermal insulation additive, which is hydrogen tungsten bronze, is get ammonium metatungstate contact with hydrogen gas or reducing gas which can release hydrogen gas at a temperature of 2500K or higher, wherein the AMT can be replaced by ammonium paratungstate or ammonium hexametungstate and ammonium dodecatungstate and AMT hydrate; the reducing and releasing hydrogen include ammonia or volatile hydrocarbons such as ethane or propane, which may be used in place of hydrogen or as a mixture with hydrogen; in a plasma, in particular when the hydrogen and / or hydrogen-evolving gases are used in admixture with a noble gas.
In addition, a invention has pointed out a method for preparing insulating material with raw material of ammonium metatungstate, by preparing ammonium metatungstate solution as a precursor, then drying it to get AMT crystal; and then, reduce AMT at 100~500°C to generate composite tungsten oxide at the reaction condition, finally to form composite tungsten oxide film to play a role of heat insulation.
| AMT Supplier: Chinatungsten Online ammonium-metatungstate.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News&Tungsten Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
2016.11.08-Tungsten Copper Rod Price
- Category: Tungsten Copper Price
- Published on 08 November 2016
- Hits: 1519
As reported by Chinatungsten Online, the current price of 80%W20%Cu tungsten copper rod of Ø12mmx200mm is $21.20 per piece EXW Xiamen, China on NOV.8, 2016.
| Tungsten Copper Supplier: Chinatungsten Online tungsten-copper.com |
Tel.: 86 592 5129696; Fax: 86 592 5129797;Email: |
| Tungsten News & Prices, 3G Version: http://3g.chinatungsten.com | Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn |
