Test Methods Used to Determine Ash Produced in Ashing Furnaces

When a sample is burnt completely in an ashing furnace, the residue consists mostly of metal oxides. Within these burnt samples, one component is ash, which is often used in the proximate analysis of biological materials. The ash content determination is the process of mineralization for the preconcentration of trace substances before an analysis such as chromatography or spectroscopy is performed.

Knowing the amount of ash-forming material present in a product can be used to determine whether the product is suitable for use in an application. This blog post will look at some of the standards used to measure ash produced in industrial furnaces.


ASTM D874 is the standard test method for sulfated ash from lubricating oils and the additives they contain. The sulfated ash is measured as it can be used to indicate the concentration of known metal-containing additives in new oils.

These additives often contain one or more of the following metals: tin, sodium, potassium, zinc, magnesium, calcium, and barium. When phosphorus is absent these metals are converted to their sulfates or oxides.

This test method is applied to sulfated ash levels below 0.02 mass% but it is restricted to oils containing ashless additives. 0.005 mass% sulfated ash is the lower limit of the test method.


ASTM D482 is the standard test method for measuring ash produced by petroleum products including crude oils, lubricating oils, waxes, distillate and residual fuels, and gas turbine fuels. Any ash-forming materials present in these products are often considered to be undesirable and a contaminant.

This test method covers the determination of ash in the range of 0.001 – 0.180 mass%. It is limited to petroleum products that are free from any added ash-forming additives, including some phosphorus compounds.

ASTM D3174

ASTM D3174 is the standard test method for measuring ash in the analysis sample of coal and coke from coal. In this method, ash is defined as the residue remaining after burning coke and coal. The composition of the ash obtained is different to the inorganic constituents present in the original coal.

Ash in this test method will differ in amount from ash performed in other furnace operations because incineration conditions influence the chemistry and the amount of ash.

Ashing Furnaces from Thermcraft

Thermcraft manufacture standard and custom ashing furnaces that conform to the ASTM specifications mentioned above. If you have any questions about our ashing furnaces and standards please contact us.