about Lithium Tungstate

Lithium tungstate is the inorganic compound with the formula Li2WO4, appears white solid that is soluble in water. The compound is one of the several other tungstates, compounds that feature the tetrahedral WO42- anion.

Lithium tungstate is used to produce high density water solutions. This use was developed in the early 1990s to address issues with existing high density fluids such as toxicity, safety, and stability, It can safely be used in an indoor environment without a fume hood with only ordinary common sense safety precautions such as protective gloves and safety glasses.

The salt consists of tetrahedral coordinated Li and W content bridged by oxides. The solid undergoes phase transitions at high pressures, such that the coordination geometry at tungsten becomes octahedral.

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Applications of Tungsten Disulfide

Tungsten Disulfide whose chemical formula is WS2, can be used in high temperature and high pressure applications. It offers temperature resistance from -270º C to 650º C in normal atmosphere and from -188º C to 1316º C in Vacuum. Load bearing ability of coated film is extremely high at 300,000 psi. WS2 can also be used instead of molybdenum disulfide-MoS2. 

 The WS2 powder could be mixed with wet lubricants:
The tungsten disulfide powder can be mixed 1wt% to 15wt% (as users required) with grease or oil. This will enhance lubricity of the mixture and also improves High Temperature and Extreme Pressure properties of mixture. During the use, tungsten disulfide in the mixture will get coated on mating/moving parts, which in turn reduces friction and improves lubricity and load bearing ability for much longer cycles.

The tungsten disulfide powder can be coated by spraying (at 120 psi) the substrate with dry & cool pneumatic air. It does not require any binders and spraying can be done at normal room temperature. Coated film will be 0.5 um thick. In an alternative application method,  tungsten disulfide powder could be mixed with Propyl alcohol and this paste could be buffed to the substrate. 

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Storage of Tungsten Powder

There are several requirements on storage of tungsten powder as following:
*Should be stored in shady, cool and ventilated warehouse.
 *Keep far away from fire, heat source and acid. 
*Smoking in the workplace is absolutely prohibit. 
*Should be available fire fighting equipment such as extinguisher . 
*Stored in vacuum encapsulation in case of being oxidized.

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New Opened Tungsten Mine in UK

As reported, tungsten mine in UK opened recently. Exact information as following:

"The £123 million Hemerdon project, near Plymouth, Devon, is reportedly the third largest tungsten resource in the world.

When complete the mine will feature an 850m x 450 m open cast pit extending to a depth of 200 m, together with a processing plant and integrated mine waste facility. 

Production is expected to start in 2015 and is scheduled to produce 3,450 tonnes of tungsten concentrate annually – equivalent to approximately 3.5% of global forecast demand – providing security of supply for tungsten and valuable export revenue for the UK, according to Wolf Minerals."

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Preparing AMT from APT

A process for preparing ammonium metatungstate (AMT) using ammonium paratungstate/APT as raw material comprising: leaching wet ammonium paratungstate/APT with nitrite acid to obtain a dilute solution of ammonium metatungstate; concentrating the dilute solution of ammonium metatungstate /AMT to be a concentrated solution of ammonium metatungstate/AMT; and spray-drying the concentrated solution of ammonium metatungstate/AMT to obtain powder of ammonium metatungstate/AMT.

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Tungsten Trioxide Photocatalysts:

Hexagonal (h-) and monoclinic (m-) tungsten trioxide (WO₃₎ nano particles with controlled composition  were prepared through annealing (NH₄)_xWO_3−y. The formation, structure, composition, morphology, and optical properties of the samples were analyzed by powder X-ray diffraction, scanning and transmission electron microscopy combined with electron diffraction, and Raman, X-ray photoelectron, H magic angle spinning nuclear magnetic resonance, diffuse reluctance ultraviolet–visual, and photoluminescence spectroscopy. Oxidized m-WO₃ (m-WO₃ ox) was the most active photocatalyst both in the aqueous and in the gas phase, followed by the oxidized h-WO₃ (h-WO₃ ox) sample. Reduced h-WO₃ (h-WO₃ red) and m-WO₃ (m-WO₃ red) exhibited much lower activity. Thus, in contrast to TiO₂, where crystalline structure (rutile or anatase) plays a key effect in photocatalysis, for WO₃, it is the composition that is of greatest importance: the more oxidized the WO₃ sample, the better a photocatalyst it is. The crystal structure of WO₃ has only an indirect effect, in that it influences the composition of WO₃ samples. Consequently, an oxidized monoclinic WO₃ material will always provide better photocatalytic activity than an oxidized hexagonal one.

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Nanostructure -- WO3

Nanostructured WO₃ has been developed as a promising water-splitting material due to its ability of capturing parts of the visible light and high stability in aqueous solutions under acidic conditions. In this review, the fabrication, photocatalytic performance and operating principles of photoelectrically cells (PECs) for water splitting based on WO₃ photoanodes, with an emphasis on the last decade, are discussed. The morphology, dimension, crystallinity, grain boundaries, defect and separation, transport of photo generated charges will also be mentioned as the impact factors on photocatalytic performance.

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XPS studies on tungsten oxide nano-wire film

WO₃ nano-wire film was bombarded by Ar ion beam in the analysis chamber of an X-ray photo electron spectroscopy (XPS) system to produce uniform tungsten cone arrays. The WO₃ nano-wire film itself served as an etching mask during the Ar⁺ bombardment. The changes of surface chemical states and electronic structures during bombardment were monitored by in situ XPS. The morphological evolution with different Ar⁺bombardment time was observed by ex situ scanning electron microscopy (SEM). At the start of Ar⁺bombardment partial W⁶⁺ in WO₃ was reduced to W⁵⁺ immediately, subsequently to W⁴⁺ and then to W^x+(intermediate chemical state between W⁴⁺ and W⁰), finally to W⁰. Multiple oxidation states of tungsten coexisted until finally only W⁰ left. SEM images showed that the nano-wires were broken and then fused together to be divided into clusters with a certain orientation after long-time high-energy ion beam bombardment. The mechanism of the ion-induced reduction during bombardment and the reason of the orientated cone arrays formation were discussed respectively.

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Crystal Structure of Zirconium Tungstate

The arrangement of the groups in the structure of cubic ZrW2O8 is analogous to the simple NaCl structure, with ZrO6 octahedral at the Na sites, and W2O8 groups at the Cl sites. The unit cell consists of 44 atoms aligned in a primitive cubic Bravais lattice, with unit cell length 9.15462 Angstroms.

The ZrO6 octahedral are only slightly distorted from a regular conformation, and all oxygen sites in a given octahedron are related by symmetry. The W2O8 unit is made up of two crystallographic ally distinct WO4 tetrahedral, which are not formally bonded to each other. These two types of tetrahedral differ with respect to the W-O bond lengths and angles. The WO4 tetrahedral are distorted from a regular shape since one oxygen is unconstrained (an atom that is bonded only to the central tungsten (W) atom), and the three other oxygen’s are each bonded to a zirconium atom (i.e. the corner-sharing of polyhedral).

The structure has P213 space group symmetry at low temperatures. At higher temperatures, a centre of inversion is introduced by the disordering of the orientation of tungstate groups, and the space group above the phase transition temperature (~180C) is Pa .

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Zirconium Tungstate Definition by Wiki

At high pressure, zirconium tungstate undergoes a series of phase transitions, first to an amorphous phase, and then to a U3O8-type phase, in which the zirconium and tungsten atoms are disordered.

Zirconium tungstate (Zr(WO4)2) is a metal oxide with unusual properties. The phase formed at ambient pressure by reaction of ZrO2and WO3 is a metastable cubic phase, which has negative thermal expansion characteristics, namely it shrinks over a wide range of temperatures when heated. In contrast to most other ceramics exhibiting negative CTE (coefficient of thermal expansion), the CTE of ZrW2O8 is isotropic and has a large negative magnitude (average CTE of -7.2x10−6K−1) over a wide range of temperature (-273 °C to 777 °C). A number of other phases are formed at high pressures.

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about ammonium paratungstate (APT)

Ammonium paratungstate, (APT) is a white crystalline salt of ammonium and tungsten.

APT is produced by 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 oxide. At that point, the oxide is heated in an atmosphere of hydrogen, reducing the tungsten to powder, leaving behind water vapor. From there, the tungsten metal powder can be fused into any number of things, from wire to bars to other shapes.

The WO3 content of APT manufactured and supplied by Chinatungsten Online is over 88.5%.

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What does APT stand for?

What does APT stand for?

In tungsten industry, APT is stand for ammonium paratungstate, whose chemical formula is 5(NH4)2O.12WO3.xH2O. APT is produced separating tungsten from its ore. APT is heated to its decomposition temperature, 600 °C. Left over is WO3, called tungsten trioxide. Tungsten oxide is heated in an atmosphere of hydrogen, reducing the tungsten to elemental powder--tungsten powder. The tungsten powder can be fused into any number of things, from wire to rods to other shapes.

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tungsten oxide with nanostructure

Metal oxides are the key ingredients for the development of many advanced functional materials and smart devices. Nanostructuring has emerged as one of the best tools to unlock their full potential. Tungsten oxides (WO_x) are unique materials that have been rigorously studied for their chromism, photocatalysis, and sensing capabilities. However, they exhibit further important properties and functionalities that have received relatively little attention in the past. This Feature Article presents a general review of nanostructured WO_x, their properties, methods of synthesis, and a description of how they can be used in unique ways for different applications.
Nano tungsten oxide particles are produced by wire explosion process. It is realized that by exploding tungsten conductor in lower pressure of oxygen, unreacted phase of tungsten was present and it could be reduced by increasing the operating pressure and increasing the amount of energy deposited to the exploding conductor. 

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Tungsten Oxide Powder Synonyms

Tungsten oxide powder is called tungsten oxide , is compound of tungsten and oxygen.

Tungsten Oxide Powder Synonyms as following:
tungsten oxide, tungsten(IV) oxide (WO2), tungsten(VI) oxide (WO3), tungsten trioxide, tungsten(VI) trioxide, tungstic anhydride (WO3), ditungsten pentaoxide, tetratungsten undecaoxide, tungsten oxide, tungsten oxide (W2O5), scheelite, wolframite, ferberitetungsten oxide (W4O11),  
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about Tungsten Oxide Film

Thermodynamically, tungsten trioxide (WO3) is reported to be stable in acidic
environments. However, the relatively high dissolution rate of WO3 in acidic solution has long been recognized by those investigating the mechanism of WO3
 coloration (electrochromism) for application in the flat panel display industry(2). To date the exact mechanism by which this dissolution process occurs remains elusive. While in alkaline environments the dissolution of WO3 is both thermodynamically favorable and experimentally observed, there has been no generalgreement on the dissolution mechanism. To examine oxide composition, structure, and hydration as a function of solution pH and applied potential in situ, surface enhanced Raman spectroscopy was employed. In addition,electrochemical impedance spectroscopy was used in conjunction with rotating disk electrode experiments to examine the effects of mass transport on the native tungsten oxides as a function of solution pH and applied potential.

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Computed Properties of Cesium Tungstate

Computed Properties of Cesium TungstateMolecular Weight:513.6485 [g/mol]
Molecular Formula:Cs2O4W-6
H-Bond Donor:0
H-Bond Acceptor:4
Rotatable Bond Count:0
Exact Mass:513.741485
MonoIsotopic Mass:513.741485
Topological Polar Surface Area:4
Heavy Atom Count:7
Formal Charge:-6
Complexity:0
Isotope Atom Count:0
Defined Atom Stereocenter Count:0
Undefined Atom Stereocenter Count:0
Defined Bond Stereocenter Count:0
Undefined Bond Stereocenter Count:0
Covalently-Bonded Unit Count:7

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Phosphotungstic Acid

Phosphotungstic acid (PTA), tungstophosphoric acid (TPA), is a heteropoly acid with the chemical formula H3PW12O40. It is normally present as a hydrate. EPTA is the name of ethanolic phosphotungstic acid, its alcohol solution used in biology. It has the appearance of small, colorless-grayish or slightly yellow-green crystals, with melting point 89 °C (24 H2O hydrate). It is odorless and soluble in water (200 g/100 ml). It is not especially toxic, but is a mild acidic irritant. The compound is known by a variety of different names and acronyms (see 'other names' section of infobox).
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Cadmium Tungstoborate

 

CAS No. 1306-26-9
Chemical Name: CADMIUM BOROTUNGSTATE
Synonyms: CADMIUM TUNGSTOBORATE;CADMIUM BOROTUNGSTATE
CBNumber: CB0687173
Molecular Formula: B2Cd5H36O98W24
Formula Weight: 6600.06
MOL File: 1306-26-9.mol
CADMIUM BOROTUNGSTATE Property
Safety
RIDADR : 2570
HazardClass : 6.1(b)
PackingGroup : III

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Sodium Phosphotungstate

CAS No. 51312-42-6
Chemical Name: SODIUM PHOSPHOTUNGSTATE
Synonyms: 12wo3·h3po4·x h2o;Sodium phosphotungst;SodiuM phosphotungstat;SODIUM PHOSPHOTUNGSTATE;SODIUM TUNGSTOPHOSPHATE;Sodium phosphowolframate;phosphotungstic acid sodium;SodiuMdodecatungsto phosphate;PHOSPHOTUNGSTIC ACID SODIUM SALT;SODIUM PHOSPHOTUNGSTATE N-HYDRATE
CBNumber: CB6161066
Molecular Formula: Na3O40PW12
Formula Weight: 2946
MOL File: 51312-42-6.mol
SODIUM PHOSPHOTUNGSTATE Property
mp : 350°C 
storage temp. : Store at RT.
CAS DataBase Reference: 51312-42-6(CAS DataBase Reference)
Safety
Hazard Codes : Xn
Risk Statements : 36/37/38-22
Safety Statements : 26-36
RIDADR : 1479
WGK Germany : 3
RTECS : TH5775000
HazardClass : 5.1
PackingGroup : III

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