Tungsten is a valuable metal that is commonly found in mineral concentrates, and accurate assay of tungsten content is essential for trading and processing purposes. There are several analytical techniques that can be used for tungsten assay in concentrates, each with its own advantages and limitations. The specific method used may depend on the expected concentration of tungsten in the concentrate and the accuracy and precision required.

Typically, tungsten is assayed in concentrates by using a combination of analytical techniques that can accurately measure the concentration of tungsten and other impurities in the sample. These techniques may include atomic absorption spectroscopy (AAS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray fluorescence (XRF), or other methods. The working range for each technique may vary depending on the specific method and instrument used, as well as the expected concentration of tungsten in the sample.

In addition to the analytical method, the sample preparation for tungsten assay in concentrates is also critical for obtaining accurate and representative results. The sample preparation may involve obtaining a representative sample, homogenizing the sample, and preparing the sample for analysis. It is important to follow the specific preparation guidelines for the analytical method to be used to ensure accurate results.

Accurate assay of tungsten in concentrates is essential for ensuring that the concentrate meets the specifications required by the end user, and for determining the value of the concentrate in trading and processing. By using appropriate analytical techniques and following standard sample preparation procedures, tungsten content in concentrates can be accurately and reliably determined.

There are several methods that can be used to assay the tungsten content in concentrate samples, each with their own advantages and limitations. Some common tungsten assay methods with their corresponding working ranges are:

X-ray fluorescence (XRF) spectroscopy: XRF is a non-destructive method that can analyze the chemical composition of a sample without damaging it. XRF is a commonly used technique to measure tungsten concentrations in ores and concentrates, with working ranges typically between 0.01% and 80% tungsten.

Inductively coupled plasma optical emission spectrometry (ICP-OES): ICP-OES is a highly sensitive and precise method for determining the elemental composition of a sample. It can measure tungsten concentrations in a wide range of materials, including tungsten concentrates, with working ranges typically between 0.01% and 100% tungsten.

Atomic absorption spectrometry (AAS): AAS is a highly sensitive and accurate method for measuring the elemental composition of a sample. It can measure tungsten concentrations in a wide range of materials, including tungsten concentrates, with working ranges typically between 0.001% and 10% tungsten.

Colorimetry: Colorimetry is a simple and cost-effective method for determining the tungsten content of a sample. It involves the reaction of a tungsten-containing solution with a reagent that produces a color change, which can be quantified using a spectrophotometer.
Colorimetry is typically used for low-concentration tungsten samples, with working ranges typically between 0.0001% and 1% tungsten.

Gravimetry: Gravimetry is a highly accurate and precise method for determining the tungsten content of a sample. It involves the precipitation of tungsten from a solution using a reagent, followed by the determination of the mass of the precipitate. Gravimetry is typically used for high-concentration tungsten samples, with working ranges typically between 10% and 100% tungsten.