Ashing is a test to deduce the amount of ash forming material present in a petroleum product so as to decide its use in certain applications. Ash-forming materials are considered to be undesirable impurities or contaminants. The specimen is placed in a suitable vessel,

evaporating dish An evaporating dish is a piece of laboratory glassware used for the evaporation of solutions and Precipitation (chemistry), supernatant liquids, and sometimes to their melting point. Evaporating dishes are used to evaporate excess solvents – mo ...

crucible A crucible is a ceramic or metal container in which metals or other substances may be melted or subjected to very high temperatures. While crucibles were historically usually made from clay, they can be made from any material that withstands te ...

and ignited. It is allowed to burn until only ash and carbon remains. The carbonaceous residue is reduced to ash by heating in a

muffle furnace A muffle furnace or muffle oven (sometimes retort furnace in historical usage) is a furnace in which the subject material is isolated from the fuel and all of the products of combustion, including gases and flying ash. After the development of ...

at about 775 °C, cooled and weighed. Ashing is also performed prior to chemical analysis by

inductively coupled plasma emission spectrometry Inductively coupled plasma atomic emission spectroscopy (ICP-AES), also referred to as inductively coupled plasma optical emission spectroscopy (ICP-OES), is an analytical technique used for the detection of chemical elements. It is a type of emis ...

. Another application is the detection of asbestos content in certain products.

See also