Proximate & Moisture Analysis

Sigra test coals according to AS 1038.3-2000 Coal and coke—Analysis and testing. Part 3: Proximate analysis of higher rank coal.

In summary the tests involve:

Coal Moisture Content Determination

Putting a weighed mass of approximately 10 g of coal into a dry clean petri dish. This is placed in an urn at kept at 105°C and 110°C while flowing nitrogen through the vessel at the rate of 15 to 20 oven-volumes per hour. This is held in the oven for 90 minutes and then an additional 60 minutes or until the dish and coal weight do not change. The dish weight, coal dish weight and dry coal dish weight are recorded and converted to coal moisture content.

Ash Content Determination

This involves putting approximately 1 gm of pulverised coal into a dry clean weighed crucible and reweighing it. This is then heated in a muffle furnace at 500°C for half hour then 815°C for an hour. The crucible is then reweighed with the ash and on its own and the ash content is determined.

Volatile Matter Content Determination

This involves weighting approximately 1 gm of coal into a ceramic Volatile Matter crucible. The crucible is then placed into the pre-heated muffle furnace at 900°C for 7 minutes. The crucible is then reweighed and the lost volatile matter is calculated.