Tungsten chemicals · (NH₄)₁₀(H₂W₁₂O₄₂)·4H₂O
Ammonium Paratungstate (APT)
The crystalline intermediate that anchors the tungsten supply chain — refined from concentrates and scrap, and the feedstock for every oxide and metal powder downstream.
About Ammonium paratungstate
Ammonium paratungstate is where tungsten becomes tradeable in purified form. Concentrates and scrap are digested, the tungsten taken into solution as sodium tungstate, purified by ion exchange or solvent extraction, then crystallised as APT. Nearly every impurity that would otherwise follow tungsten through to the finished powder is rejected at that crystallisation step.
This is why APT, not tungsten metal, is the commodity the industry prices and contracts against. A buyer purchasing APT is buying a known purity baseline they can calcine and reduce on their own equipment, to their own grain-size targets.
We hold WO₃ at min. 88.5% with carbon max. 0.0010%. Crystal size runs 30–70 µm average Fisher, with −100 mesh standard screening and apparent density 30–55 g/in³. Crystal size matters downstream because it influences how the material behaves through calcination and reduction, and therefore the grain size of the metal powder eventually produced from it.
Specifications
| WO₃, min. | 88.5 % |
|---|---|
| Carbon, max. | 0.0010 % |
| Average crystal size (Fisher) | 30.0 – 70.0 µm |
| Apparent density | 30 – 55 g/in³ |
| Standard screening | −100 mesh |
| Appearance | White crystalline powder |
| Full chemistry | Composition table stated per CoA |
Specifications can be tailored to order. Confirm your target values with us before placing an order and we will state honestly whether they are achievable.
Why crystal size matters to your process
APT crystal size is not a cosmetic specification. It carries through calcination into the oxide and through hydrogen reduction into the metal powder, so buyers reducing APT in-house treat it as the first control point on final grain size.
30–45 µm
Finer downstream metal powder targets and faster, more uniform calcination.
45–60 µm
General-purpose reduction feedstock covering most metal powder grades.
60–70 µm
Coarser metal powder targets and bulk chemical conversion where handling and flow lead.
Applications
Tungsten oxide production
Calcining APT drives off ammonia and water to give blue or yellow tungsten oxide, depending on atmosphere and temperature. This is the first step of the normal route to metal powder.
Tungsten metal powder production
Oxide from calcined APT is reduced in hydrogen to metallic tungsten. Producers who reduce in-house buy APT precisely so they control grain size themselves rather than inheriting someone else's reduction schedule.
Tungsten chemical manufacture
APT is the starting material for tungstates, tungstic acid and catalyst precursors, where its low carbon and controlled impurity profile carry directly into the product.
Catalyst precursors
Hydrotreating and selective oxidation catalysts use tungsten compounds derived from APT, and are typically sensitive to exactly the trace contaminants that APT crystallisation rejects.
Quality control
- WO₃ assay on every lot
- Carbon determination to the 0.0010% maximum
- Fisher average crystal size
- Apparent density and −100 mesh screening check
- Full composition table on the certificate of analysis
Manufactured under an ISO 9001:2015 certified quality management system.
Packaging and export
Packed in lined drums or bags with moisture barrier, palletised for container shipment. APT is stable in normal storage but loses ammonia if heated, so it is kept cool and dry in transit.
Commercial invoice, packing list, certificate of analysis and certificate of origin are supplied as standard with every export shipment.
Ammonium paratungstate — frequently asked questions
What WO₃ content do you guarantee?
Minimum 88.5% WO₃, with carbon held to max. 0.0010%. A full composition table is supplied on the certificate of analysis for every lot.
What crystal size is available?
Average Fisher size 30–70 µm with −100 mesh standard screening and apparent density 30–55 g/in³. If you are reducing in-house, tell us your target metal powder grain size and we will advise which crystal size suits.
Why buy APT rather than finished tungsten powder?
Control. APT gives a known purity baseline that you calcine and reduce on your own equipment to your own grain-size targets, instead of inheriting another producer's reduction schedule. It is also the form the industry prices and contracts against.
How should APT be stored?
Cool and dry, in its moisture barrier packaging. APT is stable under normal storage conditions but will begin to lose ammonia if heated, which shifts the assay.
Can you supply composition data for REACH purposes?
Yes. A full composition table is provided on the certificate of analysis to support safety data sheet obligations and incoming-material qualification for chemical imports.
Ammonium paratungstate export destinations
Country-specific specifications, logistics and compliance notes for this product: