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Zinc in Australian export thermal coals

An examination of zinc in Australian export thermal coals intended for industrial, scientific and research audiences.

  • 21 July 2010 | Updated 14 October 2011

Trace elements in coals may be associated with specific minerals or with organic 'coaly' matter.

The sources of trace elements include biological material (plants, algae and bacteria) that is the precursor of the coaly material, water in the peat swamp and mineralogical material washed or blown into the swamp.

Table representation of zinc in Australian export coals, other internationally traded coals, the Earth's crust and shales.
 Concentration of zinc in: mg/kg 
 Australian export coals  4 - 51 (14) #
 Other internationally traded coals  4 - 168 (18) #
 Earth's crust  70
 Earth's shales  100
 # values in parentheses are averages


Zinc is not identified as a Hazardous Air Pollutant (HAP) by environmental authorities.

Modes of occurrence

Zinc is present as sphalerite and in pyrite in bituminous coals. It is thought also to be present in carbonates.

Behaviour during combustion

Zinc is vaporised during combustion and is enriched on the finer ash particles.

Health and environmental effects

There does not appear to be any reports of adverse health or environmental impacts from zinc emissions from the utilisation of coal in power stations.

Analytical methods

There are a number of standard methods for determining zinc in coal.

AS 1038.10.0, Australian Standard, Coal and coke - Analysis and testing - Part 10.0: Determination of trace elements – Guide to the determination of trace elements.

ASTM D6357-00a Test Methods for Determination of Trace Elements in Coal, Coke, & Combustion Residues from Coal Utilization Processes by Inductively Coupled Plasma Atomic Emission, Inductively Coupled Plasma Mass, & Graphite Furnace Atomic Absorption Spectrometries.

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This work supported by:

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