How tungsten concentrate is priced: MTU, WO₃ and the APT benchmark

Buyers new to tungsten often ask why a concentrate offer never quotes a simple price per tonne. The answer is that the tungsten concentrate price is built from three elements: the tungsten content of the material, measured in metric tonne units of WO₃; a reference price, usually linked to ammonium paratungstate (APT); and the contract terms that adjust for grade, impurities and delivery. This explainer sets out how those pieces fit together.

The metric tonne unit (MTU)

Tungsten is traded on its content, not its gross weight. The unit of account is the metric tonne unit, or MTU. One MTU is 1% of a metric tonne, that is 10 kg, of tungsten trioxide (WO₃). Because tungsten makes up about 79.3% of WO₃ by weight, one MTU contains roughly 7.93 kg of tungsten metal, as the Minor Metals Trade Association sets out in its APT specification.

The calculation is simple:

One dry metric tonne of concentrate at 65% WO₃ contains 65 MTU.
A 20-tonne lot at 65% WO₃ therefore contains 1,300 MTU.
The invoice value is the number of MTU multiplied by the agreed price per MTU.

Two points matter in practice. First, content is measured on a dry basis: moisture is determined at loading and deducted before MTU are counted. The US Geological Survey, for example, reports concentrate prices per dry metric tonne unit of WO₃. Second, the WO₃ grade is set by assay, so the sampling and assay procedure written into the contract directly affects the value of every lot.

Why APT is the reference

Most tungsten concentrate is not consumed directly. It is converted into APT, the main intermediate traded in the international tungsten market, and from APT into oxides, powders, carbide and ferrotungsten. Because APT is the most widely traded form, it has long served as the benchmark for the whole chain. APT itself is also quoted per MTU of WO₃.

Concentrate is therefore usually priced with reference to APT. A common structure links the concentrate price to a published APT assessment, either as a percentage of that price or with a deduction that reflects the cost of converting concentrate into APT. The exact percentage depends on grade, impurity profile, volume and the balance of supply and demand at the time of the contract.

Price reporting agencies publish APT assessments, typically on a Rotterdam or other international basis. Some have also moved to assess concentrate directly. In late 2025, Fastmarkets proposed a concentrate assessment for material of 50–70% WO₃, quoted in US dollars per MTU, on a CIF Rotterdam or CIF Baltimore basis, citing demand for price visibility that better reflects how concentrate trades. These assessments are subscription data; buyers and sellers agree in the contract which assessment applies and how it is averaged.

China's domestic market works differently. Chinese producers and price services quote concentrate in renminbi per "standard tonne" of 65% WO₃ wolframite or scheelite concentrate, alongside APT and powder prices. Large Chinese producers also publish their own long-term contract quotations, which many domestic traders watch closely.

Concentrate and APT do not always move together

Because concentrate and APT are linked, buyers sometimes assume the two prices move in lockstep. They do not. When concentrate is scarce, its price can rise faster than APT and squeeze converters. The Minor Metals Trade Association described such a period in 2024, when APT selling prices fell below the cost of buying concentrate and some converters reported losses. The reverse can happen when concentrate supply eases.

Public data show how far the reference itself can move. According to the USGS, the Rotterdam APT price rose from about $331 to about $675 per MTU over 2025, after China introduced export controls on selected tungsten products. A percentage-of-APT formula passes that volatility straight through to the concentrate price.

Grade and impurities

The headline grade is only part of the picture. Converters set limits for elements that complicate processing or affect product quality. The Fastmarkets concentrate specification, for example, sets maximum levels for molybdenum and for uranium plus thorium, and refers to silica content. Individual contracts add further limits that depend on the converter's process, so the full impurity schedule should be checked line by line.

Material outside the agreed limits may attract a price deduction or be rejected. Wolframite and scheelite concentrates also suit different processing routes, so the mineral type is part of the specification, not a detail.

Contract terms that change the number

Beyond the reference price and the grade, several terms shape what a buyer actually pays per MTU:

Quotational period: which dates of the reference price are averaged, for example the month of shipment or the month after.
Delivery basis: FOB, CFR or CIF, which decides who carries freight and insurance.
Sampling and assay: who samples, which laboratory assays, and how differences between results are settled.
Weights and moisture: where the lot is weighed and how moisture is measured.
Payment terms: provisional and final payment, and the share paid against documents.

The Minor Metals Trade Association also notes that major tungsten producers sell most of their concentrate on long-term arrangements rather than on the spot market, which means published spot assessments describe only part of the trade.

What buyers should check

The WO₃ grade on a dry basis, and the sampling and assay method behind it.
Which APT or concentrate assessment the price is linked to, and the averaging period.
Impurity limits and the deduction schedule for material outside them.
Whether the mineral type suits your process.
The delivery basis and who bears freight, insurance and inspection costs.

For specifications and grades available, see our tungsten page.