China Ammonium Paratungstate Market (APT Market) On July,2013

China ammonium paratungstate prices (APT prices) keep firm.

China ammonium paratungstate market (APT market) keeps quiet this week, and the market participants are cautious in making deals. Most of them are watching the market, and the APT prices are stable now.

A source from an APT factory based in South China noted that they mainly dealt with the old orders in the recent days.

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China Tungsten Concentrate Market

China tungsten concentrate prices move up gradually, but the downstream markets are unfavorable. According to the formula,the APT price = (tungsten concentrate price *1.45)+11,000. In early March, the wolframite 65% prices were at RMB118,000-120,000/t (USD217-221/mtu), and the APT prices should be at RMB182,000-185,000/t (USD336-341/mtu), but the prices were only at RMB179,000-181,000/t (USD330-334/mtu) in the spot market, and some offers were even lower.

Later, as tungsten concentrate prices were pushed up  further, the APT prices were always at below the production cost. Although the APT prices moved up accordingly into April, the increasing speed was slow. This is one of the puzzlements of increasing tungsten concentrate prices.

With the increasing tungsten concentrate prices, the downstream tungsten powder and cemented carbide markets are unfavorable. As the tungsten concentrate and APT prices move up, the tungsten powder factories raise offers. But the demand from the downstream cemented carbide market remains soft, and the consumption is small. The trading is thin in the spot market. Moreover, under the current APT prices, the tungsten powder prices are lower than the production cost. The tungsten powder factories are running with difficulties.

Furthermore, most of the downstream factories hold some stocks, which could be consumed in around two months. Therefore, the customers are inactive in making deals. However, cemented carbide factories intend to maintain regular customers, so they have to hold offers stable even though the production cost moves up continuously with the increasing raw materials prices.

Now, some companies keep purchasing the materials in the spot market. The tungsten concentrate and APT prices show uptrend, and tungsten powder prices will follow up in the future. Moreover, if the tungsten prices remain at high level after several months, the downstream enterprises and overseas customers will accept the increasing offers. However, whether the market could move up further or not is unclear as it still depends on the supply and demand in the spot market. 

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Cadmium tungstate

Cadmium tungstate is a high density, high Z scintillator with relatively high light yield. The emission maximum is at 475 nm, and the total light output is 12 to 15 photons/keV). The light yield relative to NaI(Tl) on a bialkali PMT is 30 to 50%

 

The intensity of the scintillation emission of CdWO4as a function of the temperature is shown in Figure 2 (irradiation with γ-rays). At room temperature (25oC), the curve is relatively flat (-0.1%/oC) which can be important for some applications.

 

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RPT-Fitch affirms AMT Management Limited at 'A-'; outlook stable

The M1 is a critical element within the Sydney orbital road network connecting Sydney's central business district with Sydney Airport, and provides key linkages to the Sydney Harbour Tunnel, Sydney Harbour Bridge and the city's northern and south-eastern suburbs.
Revenue for the year to 30 June 2013 (FY13) was AUD100.5m, up 8.4% over the prior year. The growth was due mainly to an increase of 50 cents in the toll rate for cars and motorcycles to AUD6.00 on 1 July 2012. Traffic was relatively flat, with annual average daily traffic up only 0.1% for the year. The lack of growth in traffic numbers is likely due in part to the toll increase at the beginning of the fiscal year, as well as to the introduction of fully electronic tolling in 2011, which caused some cash users to divert from the road. The M1 may have also been affected by construction on other roads in the Sydney orbital network that connect to it, and from slower economic growth in the overall economy. Traffic is expected to return to a steady growth of 1-2% over the next several years. The volume risk attribute is assessed as "midrange".AMT has continued to raise tolls at the maximum level allowed under the concession agreement, with a CAGR of around 5% since operations commenced. Toll prices are escalated in increments of AUD0.50, which can result in some flattening of demand following each increase. The concession agreement allows toll increases of at least 1% per quarter, which is steep and may impact long term volume growth. Tolls currently stand at AUD6.00 for cars (Class A) and AUD12.00 for other vehicles (Class B). Price risk is assessed as "midrange".
While typical of the Australian market, the bullet debt structure is a weaker attribute compared to other Fitch monitored toll roads globally. However, AMT and its main sponsor Transurban (whose financing arm is Transurban Finance Company Pty Limited ('A-'/Stable)) have proven track records of refinancing debt well in advance of maturity. AMT also benefits from Transurban's strong global banking relationships. Structural features include: medium term interest rate hedging requirements; a higher interest coverage cash lock-up than the last loan package; and a major maintenance letter of credit. Fitch expects that refinancing of the Tranche A debt will be completed by January 2014, six months prior to maturity. The debt structure attribute is assessed as "midrange".
AMT has a demonstrated ability to withstand downside events and maintain its robust historical interest-only coverage ratio (ICR) above 2.0x. Coverages have declined somewhat as the cash flows from infrastructure bonds have run off, but the minimum ICR (calculated assuming no amortisation until 2037) in Fitch's Rating Case is still fairly strong at 1.85. The Rating Case assumes in particular toll rate increases of 4% per year, long term traffic growth of 1% resulting notably from adverse price elasticity, and moderate stresses to operating and maintenance costs and interest costs. The Rating Case concession life coverage ratio (CLCR) of 2.93 and average debt service coverage ration (DSCR), on a notional 25-year amortisation starting in 2014, of 3.13, benefit from the lengthy concession period, and are within the 'A-' rating category.
Assuming lower toll rate increases at 2% per annum would result in CLCR of 2.28 and average DSCR of 2.31. These levels are materially below the Rating Case but still robust. The debt service risk attribute is assessed as "stronger".
The M1's major maintenance requirements are well managed by Transurban, with the costs fully funded by cashflow from operations. Management does not expect to develop M1 above its current capacity of 82,000 vehicles per day, but plan to continue to maximize revenues from the existing traffic to meet debt service. The infrastructure development and renewal attribute is assessed as "stronger".

RATING SENSITIVITIES
AMT's ratings would come under downward pressure from financial deterioration such that leverage was forecast to be still above 6x by 2015, or if the Tranche A refinancing was delayed beyond January 2014.

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Report covers the future of tungsten in China

China, as the world’s largest tungsten resource country, holds 58.95% of global tungsten reserves and supplies and around 85% of tungsten ore worldwide. In 2012, China newly added 200,000 tons of tungsten reserves and output 131,100 tons of tungsten concentrates, down 3.35% from a year earlier. Exposed to the restrictive policies on control of exploitation amount and export quotas as well as new limited prospecting of resources, etc, the supply and demand in tungsten market is obviously out of balance, and it is expected that Chinas output of tungsten ore will see limited growth in the upcoming several years, and that global tungsten market will be still in tight supply.

The slowdown in downstream demand from machining, electronics, real estate markets in 2012 caused the sluggish development of China tungsten industry, with the consumption of tungsten concentrate decreasing by 15.6% year-on-year and the lingering price slump.

In China, major tungsten producing regions are concentrated in Jiangxi, Hunan, Henan, Guangxi and Fujian, the combined tungsten concentrate of which occupied over 88% of China’s total in 2012. In particular, Jiangxi came out top in terms of tungsten concentrate output, registering 46,500 tons.

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Tungsten Oxide (WO3) Nanoparticles – Properties, Applications

Nanoparticle research had progressed rapidly in the recent years mainly due to the unique properties of basic elements that are brought about by altering their atomic and molecular properties. By virtue of these properties, nanoparticles have found many applications in the field of biomedicine, cosmetics, electronics, coatings and plastics, etc. This article deals with the properties and applications of tungsten oxide nanoparticles.
Tungsten oxide (WO₃) nanopowders or nanoparticles are available in the form of nanofluids or faceted high surface area oxide particles exhibiting magnetism. Other forms in which these particles are available are dispersed, transparent, high purity and coated forms.

Chemical Properties

The following tables list the chemical properties of tungsten oxide.

Chemical Data
Chemical symbol	WO3
CAS No	1314-35-8
Group	Tungsten 6 Oxygen 16
Electronic configuration	Tungsten [Xe] 4f14 5d4 6s2 Oxygen [He] 2s2 2p4

Chemical Composition
Element	Content (%)
Tungsten	79.29
Oxygen	20.69

Physical Properties

Tungsten oxide nanoparticles appear in the form of a yellow powder having a nearly spherical morphology. The table below provides the physical properties of these nanoparticles.

Properties	Metric	Imperial
Density	7.16 g/cm3	0.258 lb/in3
Molar Mass	231.84 g/mol	-

Thermal Properties

The thermal properties of tungsten oxide nanoparticles are as below.

Properties	Metric	Imperial
Melting Point	1473 °C	2683° F
Boiling Point	1700° C	3092° F

Applications

Given below are some of the chief applications of tungsten oxide nanoparticles:

• In the manufacture of conducting and semi-conducting materials
• In optics and mechanochemical applications.

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Tungsten Trioxide Hydrates and Monotungstates - 02

Tungstic Acids. In contrast to the compound of the same overall composition mentioned above, tungstic acids are highly condensed, almost insoluble and amorphous species with decreasing water content:

WO₃•2H₂0   (W : H₂O ratio 1:2)

WO₃•H₂0    (W : H₂O ratio 1:1)

2WO₃•H₂0   (W : H₂O ratio 2:1)

Within this group dehydration can be achieved by heating. Heating to approximately 500 0C leads to th500 0C leads to the final stage of dehydration, the water-free, crystallized tungsten trioxide.

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Tungsten Trioxide Hydrates and Monotungstates

Tungsten Trioxide Monohydrate: WO₃•H₂O (WO₂(OH)₂). It is a monomeric, gaseous compound which forms above 600℃ by reaction of water vapor and tungsten oxides. It is responsible for the Chemical Vapor Transport (CVT) of tungsten during the reduction process and hence for the grain size of the finally formed tungsten powder. Another important aspect of the CVT of tungsten is the overgrowth of dopant compounds by tungsten during the powder production of non-sag tungsten.

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Tungsten Oxide: W2.72 (W18O49)

PR: It also forms during the hydrogen reduction of WO₃ to W and can be obtained in pure state, for example, in hydrogen atmosphere at 900℃ and a water vapor partial pressure of 0.8 bar.

PP: D: 7.724-7.989 g•cm^-3 (measured), 7.78 g•cm^-3 (X-ray); CO: reddish violet, in whiskers brownish red; electrical resistivity: (2-3) x 10^-4 Ω•cm; -ΔH°₂₉₈ =743-780 kJ•mol^-1; CR: monoclinic, P2/m-C¹_2h; a=18.28 A, b= 3.775 A, c = 13.98 A, p = 115.14°.

The crystals are needle-shaped and the monoclinic b-axis is parallel to the needle axis; HR: WO_{2.7190-2.7224} at 1000℃.

WO_2.72 is not included in the homologous series of CS structures, because besides edge- and corner-sharing octahedral also pentagonal columns exist (as described under tungsten bronzes).

CP:About behavior with respect to hydrogen. At elevated temperature it decomposes. It is soluble in alkaline solutions. Propene oxygen mixtures are oxidized by WO_2.72 to acroleine.

A: It is partially contained in the technical blue oxide.

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Tungsten and Oxygen - 03

Several hundreds or even thousands of ternary and quaternary tungsten oxides are known today. They are only partly described in the literature and can be found in the relevant compilations. They are, however, the top of an iceberg of a much larger number of compounds which might form, in principle, with a large number of elements and/or element combinations. In this sense, the crystal chemistry of tungsten oxides can be regarded as one of the most complex and richest fields in the structural chemistry of the elements.

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Tungsten and Oxygen - 02

By the loss of each oxygen atom from the oxide lattice two electrons are added to the conduction band. Reduced compounds are therefore either semiconducting or conducting.

Besides the tungsten-oxygen octahedral, W04 tetrahedra can also be found in fully oxidized compounds (tungstates), as well as WO7 pentagonal bipyramids in reduced compounds.

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Tungsten and Oxygen

The tungsten-oxygen system is rather complex. Besides the stable stoichiometric binary oxides (WO₃, WO_2.9, WO_2.72, and WO₂); and the stoichiometric tungstates and acids, a variety of nonstoichiometric, fully oxidized and reduced compounds exists.

In the fully oxidized state (W⁶⁺) the octahedral coordination dominates (WO₆). The tungsten atoms are situated in the center of octahedrons and are surrounded by six oxygen atoms arranged at the comers. A-s long as all tungsten ions are hexavalent, these octahedrons are only comer-sharing. However, as the oxygen-to-tungsten ratio decreases, which occurs on reduction (transition to lower oxides), the octahedral become more and more intricately joined in combinations of corner-, edge-, and face-sharing.

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Copper Powder

What is copper powder?

Characteristics: Distinctive reddish color; ductile; excellent conductor of electricity. Complexing agent, coordination numbers 2 and 4. Dissolves readily in nitric and hot concentrated H2SO4, in HCl and dilute H2SO4 slowly but only when exposed to the atmosphere. More resistant to atmospheric corrosion than iron, forming a green layer of hydrated basic carbonate. Readily attacked by alkalies. A necessary trace element in human diet; a factor in plant metabolism. Essentially nontoxic in elemental form. Powder is combustible.

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Violet 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. CTOMS produces two standard grades differing mainly in oxygen content. Violet tungsten oxide is used primarily for the production of tungsten metal powder and tungsten carbide.

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Cobalt Powder

Cobalt is a hard, lustrous, gray metal, a chemical element with symbol Co and atomic number 27. Although cobalt-based colors and pigments have been used since ancient times for making jewelry and paints, and miners have long used the name kobold ore for some minerals, the free metallic cobalt was not prepared and discovered until 1735 by Georg Brandt.

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Tungsten Granule

Tungsten granule, also known as tungsten flux, is the processing of tungsten metal into small particles, particle size 20-40 mesh, high purity above 99.95%, so it also called pure tungsten flux, mainly for the purpose frequency and high-frequency combustion infrared carbon and sulfur analyzer with a flux with good fluxing, which the effect of the analysis is very stable.

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Medium Tungsten Powder

Grain size of medium tungsten powder is 2~10µm. The most common size is 3~5µm.

Appearance of medium tungsten powder: dark grey powder, stable in dry air at room temperature

Application of medium tungsten powder: medium tungsten powder is used as the material of tungsten carbide,contact alloy and high density shield ect.or used as the material of plasma spraying.

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Raw Material - Tungsten Carbide Powder

Tungsten carbide powder can be prepared from different raw materials and by various production methods. Only methods used today on a technical or pilot plan t scale are considered. The conventional procedure covers the widest range of powder qualities in regard to particle size (0.15→12um), and consequently the biggest percentage of WC presently produce while all other methods yield ,special coarse or fine-grained powders.

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Something about Tungstic Acid - 2

Tungstic acid the most important intermediate in former tungsten chemistry, is today exclusively manufactured out of APT, in order to make use of the high pirity APT level. For that purpose an aqueous APT slurry will be treated with hydrochloric acid.By that tungstic acid is precipitated ,and afterwards filtered , washed and dried.Tungstic acid has a very high active surface and is only used in small quantities for special purposes as there are : production of ultrafine W and WC powders and production of tungsten chemicals.Tungsten acid is a fine yellow powder and is packaged in sealed polyethylene-lined steel drums.
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Something about Tungstic Acid

Tungstic acid refers to hydrated forms of tungsten trioxide, WO3. The simplest form, the monohydrate, is WO3.H2O, the dihydrate WO3.2H2O is also known. The solid state structure of WO3.H2O consists of layers of octahedrally coordinated WO5(H2O) units where 4 vertices are shared. the dihydrate has the same layer structure with the extra H2O molecule intercalated between the layers. The monohydrate is a yellow solid and insoluble in water. The classical name for this acid is 'acid of wolfram'.

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Tungsten Powder Grades

Tungsten Powder Grades.

Grades	Fsss.(µ)	O2 ( %,Max. )
W-0	0.40~0.69	0.3
W-1	0.70~0.99	0.3
W-2	1.00~1.49	0.25
W-3	1.50~1.99	0.2
W-4	2.00~2.49	0.15
W-5	2.50~2.99	0.15
W-6	3.00~3.49	0.1
W-7	3.50~3.99	0.1
W-8	4.00~4.49	0.07
W-9	4.50~4.99	0.07
W-10	5.00~6.99	0.05
W-11	7.00~8.99	0.05
W-12	8.99~14.99	0.05
W-13	15.00~25.00	0.05

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REDUCTION OF TUNGSTEN HALIDES- 2

Chlorination of scheelite or wolframite ore concentrates according to the equations

2CaWO₄ + 3C + 6C₁₂→2CaCI₂ +2WOC₁₄ + 3CO₂

2FeWO₄ + 3C+ 7C₁₇→2FeC_I3 +2WOC₁₄ + 3CO₂

and subsequent treatment of the chlorides offers a selective separation of most other chlorides formed with the exception of molybdenum but bears certain disadvantages: 

*It mainly yields in the formation of WOC₁₄ and not in the desired WC₁₆.

*Therefore, an additional conversion step from WOC14 to WC₁₆ is necessary; the separation from other chlorides can be done only in the WCI₆ stage by fractional distillation.

*Calcium as well as iron or manganese form molten chlorides at the reaction temperature causing difficulties in reactor design.

*Finally, hazards associated with HCI, C1₂, COCI₂, and chlorides as well as environmental considerations are further limiting factors.

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REDUCTION OF TUNGSTEN HALIDES

The direct chlorination of tungsten raw materials and subsequent reduction of the chloride to tungsten metal would offer a much simpler and cheaper production path in comparison to the rather complicated one via hydrometallurgy to APT and a two-stage reduction to tungsten metal. Although several promising attempts have been made, it is interesting to note that chlorination chemistry of tungsten has not found its way into large-scale production, unlike other refractory metals such as zirconium, hafnium, titanium, niobium, and tantalum. None of the processes mentioned below survived for long or are in use today.

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