Tungsten Information

Ammonium Paratungstate is Synthesis

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 17:17

When concentrating an ammoniacal solution of tungstic acid (i.e. hydrous WO3), the product obtained is ammonium paratungstate. Below 50 C, the hexahydrate is formed, whereas when the temperature of the solution is above 50 °C, the pentahydrate or heptahydrate is formed. The former crystallizes as triclinic plates or prisms, whereas the latter as pseudorhombic needles.If a calcined WO3 is used, refluxing the ammonia solution is advisable to speed up the dissolution of the oxide.

Ammonium paratungstate is a white, crystalline powder with a very high degree ofchemical purity. It is used as a universal intermediate product for a variety of applications such as manufacturing tungsten oxides and tungsten metal powder, tungstic acid, ammonium paratungstate and organometallic components as well as in catalysis and fine chemistry.

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Ammonium Paratungstate Containing Two Hydrogen Atoms

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 17:12

In more recent literature, the anion in (NH4)10(W12O41)·5H2O has been shown to be [H2W12O42]10−, containing two hydrogen atoms, keeping two hydrogen atoms inside the cage. The tungsten-oxygen cage, that is the heart of the anion requires 42 oxygen molecules. The correct formula notation for ammonium paratungstate is (NH4)10[H2W12O42]·4H2O. The [H2W12O42]10−ion is known as the paratungstate ion, as opposed to the paratungstate ion, that has the formula [W7O24]6−, similar to the paramolybdate ion. The existence of the paratungstate A ion, could not be confirmed by NMR spectroscopy, however.

Before about 1930, there has been some dispute about the exact composition of the salt, and both (NH4)10W12O41 and (NH4)6W7O24 were proposed. O.W. Gibbs remarked about this:

The alkali tungstates are numerous and unusually complex. Salts of essentially different formulae approach so closely in percentage composition, that the differences lie very near the unavoidable errors of analyses. The analyses are hardly sufficiently close to decide the question upon purely analytical grounds.

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Introducing Ammonium Paratungstate

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 17:04

Ammonium paratungstate(APT) is a white crystalline salt of ammonium and tungsten, with the chemical formula (NH4)10(H2W12O42)•4H2O.
Ammonium paratungstate is produced separating tungsten from its ore. Once the ammonium paratungstate is prepared, it is heated to its decomposition temperature, 600 C. Left over is WO3,tungsten(VI) oxide. From there, the oxide is heated in an atmosphere of hydrogen, reducing the tungsten to elemental powder, leaving behind water vapor. From there, the tungsten powder can be fused into any number of things, from wire to bars to other shapes.

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What is Advantage of Dart Games?(I)

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 16:55

There are some advantage of dart games:

1.Rising chest and abdomen, can relieve fatigue cervical, lumbar, shoulder, elbow, wrist and other parts. Relax the mind, relieve stress. In particular, the health of people engaged in office work best effects, it is a modern way for people, especially for old.

2. One of arts game is that it can rivet restore movement and contraction mainly involved muscles and joints, wrist, elbow, shoulder, deltoid, triceps, wrist, finger muscles, especially for people of few muscle training exercise, exercise is not also adjust.

3, Advantage of dart games:relieve visual fatigue
When throw darts, there be completed on the basis of long-range targeting in the firing action, and after a long period of training, we can take the goal, vision tends to increase muscle strength. It is also alleviate eye fatigue caused by prolonged close work, such as regulating vision of eyes.

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Special Term for Dart Game(II)

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 16:23

Term	Meaning
ARROWS	Means dart.
BABY TON	score is 95,usually means the point is 5×19.
BAG O' NUTS	score is 95,
Barn Dart	Third darts without hit two darts when aim at the objective in the first round.
BARREL	It is means the later pinpoint of dart when you scratch
BASEMENT	Twofold of three
BREAKFAST	Continue achieve the score of 5,20,1 in the number one dart game.
Bombs/Bombers	Bigger or heaver dart
BUCKET OF NAILS	Three dart heat the 1 zone.
BUCKSHOT	Dart hit everywhere without any direction.
BULL	The central of dartboard
BULLSEYE	The central of dartboard
BUST	In this round cannot record the score for too much points in the first round.
C	There is a one time to record point in the Cricket match. such as T20-S20-S20,its called C-5，for it hit five times
CHUCKER	Throw the dart without aiming at the bull's eye.
CIRCLE IT	If one people just got point within 10,his teammate can call the record keeper to lock up.
CLOCK	dartboard
CORK	The central of dartboard
DIDDLE FOR MIDDLE	Throw a dart, if close to the bulls eye, then can begin first.
DOUBLE	The outside of dartboard have a rung ,if hit there, we can record double points.
DOUBLE IN	We need hit the double zone, then we can record the points
DOUBLE OUT	If we want win the game we need to hit the double zone.
DOUBLE TOP	Hit the double of the area of 20.
DOUBLE TROUBLE	Cannot hit the double zone.
DOWNSTAIRS	The beside part of dartboard. it is means the zone of 19 points.
EASY IN	We cannot throw darts extra when dart game begins.
FEATHERS	The tail of darts.

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Special Term for Dart Game(I)

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 16:12

There are some special term for dart game as follow:

Term	Meaning
ARROWS	Means dart.
BABY TON	score is 95,usually means the point is 5×19.
BAG O' NUTS	score is 95,
Barn Dart	Third darts without hit two darts when aim at the objective in the first round.
BARREL	It is means the later pinpoint of dart when you scratch
BASEMENT	Twofold of three
BREAKFAST	Continue achieve the score of 5,20,1 in the number one dart game.
Bombs/Bombers	Bigger or heaver dart
BUCKET OF NAILS	Three dart heat the 1 zone.
BUCKSHOT	Dart hit everywhere without any direction.
BULL	The central of dartboard
BULLSEYE	The central of dartboard
BUST	In this round cannot record the score for too much points in the first round.
C	There is a one time to record point in the Cricket match. such as T20-S20-S20,its called C-5，for it hit five times
CHUCKER	Throw the dart without aiming at the bull's eye.
CIRCLE IT	If one people just got point within 10,his teammate can call the record keeper to lock up.
CLOCK	dartboard
CORK	The central of dartboard
DIDDLE FOR MIDDLE	Throw a dart, if close to the bulls eye, then can begin first.
DOUBLE	The outside of dartboard have a rung ,if hit there, we can record double points.
DOUBLE IN	We need hit the double zone, then we can record the points
DOUBLE OUT	If we want win the game we need to hit the double zone.
DOUBLE TOP	Hit the double of the area of 20.
DOUBLE TROUBLE	Cannot hit the double zone.
DOWNSTAIRS	The beside part of dartboard. it is means the zone of 19 points.
EASY IN	We cannot throw darts extra when dart game begins.
FEATHERS	The tail of darts.

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Violet Tungsten Oxide

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 11:13

Violet tungsten oxide (VTO) is a kind of tungsten oxide. Violet tungsten oxide is a finely divided violet crystalline powder. It is produced by rotary calcining ammonium paratungstate at closely controlled temperatures in a reducing atmosphere. Violet tungsten oxide is used primarily for the production of tungsten metal powder and tungsten carbide.

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Tungsten Blue Oxide Uses

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 11:10

Blue tungsten oxide (BTO) is also called tungsten blue oxide (TBO). Tungsten blue oxide is one of the most important, highly pure intermediates for the production of other tungsten compounds including tungsten metal powder.

Tungsten blue oxides are finely divided blue-violet powders.They are produced by heating ammonium paratungstate at closely controlled temperatures in a reducing atmosphere. GTP produces two standard grades differing mainly in oxygen content. Tungsten blue oxide is used primarily for the production of tungsten metal powder and fine tungsten carbide as well as wire products.

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Partial Thermal Reduction of Ammonium Paratungstate Tetrahydrate

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 11:05

Thermal decomposition of ammonium paratungstate tetrahydrate, (NH₄)₁₀[H₂W₁₂O₄₂]·4H₂O has been followed by simultaneous TG/DTA and online evolved gas analysis (TG/DTA-MS) in flowing 10% H₂/Ar directly up to 900°C. Solid intermediate products have been structurally evaluated by FTIR spectroscopy and powder X-ray diffraction (XRD). A previously unexplained exothermic heat effect has been detected at 700–750°C. On the basis of TG/DTA as well as H₂O and NH₃ evolution curves and XRD patterns, it has been assigned to the formation and crystallization heat of γ-tungsten-oxide (WO_2.72/W₁₈O₄₉) from β-tungsten-oxide (WO_2.9/W₂₀O₅₈) and residual ammonium tungsten bronze.

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Tungsten Oxide Nanowires

Details: Category: Tungsten Information; Published on Thursday, 05 February 2015 11:03

Tungsten oxide nanowires were prepared by a vapor transport method using yellow tungsten oxide powder as a raw material. The crystal structure and morphology of WO3 nanowires were investigated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The obtained nanowires were hexagonal WO3.

The major factors that influenced the morphology were the furnace temperature and the substrate position. The diameter of the nanowires decreased as the distance of the substrate from the raw material increased. Sensors were fabricated by pouring a few drops of nanowire-suspended ethanol onto oxidized Silicon substrates equipped with a pair of interdigitated Pt electrodes. The sensor made of the nanowires as thin as 50 nm showed the highest response to NO2 at a low operating temperature of 100 °C. The temperature dependence of the response was discussed in relation to the formation of NO2− and NO3− ions on the surface of WO3. The response slightly increased with decreasing diameter if the nanowires are regional depleted in NO2, while it largely increased if the nanowires are in volume depletion. A theoretical calculations based on assumptions were proposed in order to clarify the correlation between the nanowire response and their diameter.

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