A digitally altered image showing a eucalyptus seedling growing from a lump of coal.

Soft and hardwoods could be used to produce carbon anodes.

Wood char shows potential for carbon anode production

Research to replace petroleum coke and coal tar pitch with carbon alternatives could benefit aluminium producers and the environment.

  • 29 March 2007 | Updated 14 October 2011

Carbon anodes

Replacing petroleum coke and coal tar pitch with carbon alternatives could improve supply and quality issues for Australia’s aluminium industry, plus benefit the environment by offsetting carbon.

The aluminium industry relies on petroleum coke and coal tar pitch to produce high-quality, dense carbon anodes. However, declining coke quality, security of supply and environmental concerns, threaten the quality of aluminium production and is driving the development of alternative carbon sources.

An alternative material for use in carbon anode production

One alternative being explored by researchers through the Light Metals Flagship is the use of wood char to produce carbon anodes.

Biomass is an attractive alternative because it is renewable and has low sulfur and ash content.

Using biomass for anodes production would also make the process greenhouse neutral – carbon dioxide liberated in the production process is absorbed by the successive growing of trees.

However the low density of wood char means additional processing is required to produce aluminium anodes.

Researchers are blending charcoal with biopitch to make a coke-like material in an effort to overcome this issue.

The process is greenhouse-neutral: carbon dioxide liberated in aluminium production is absorbed by the successive growing of trees.

Characterising various charcoals and their properties is an important part of the project. This knowledge will help researchers develop bioanodes that perform the same function as traditional anodes. 

Early research suggests anode production from softwoods and hardwoods will require different process methods because of their unique cellular structures.

Benefits

By developing and maintaining their own plantations, aluminium producers would help close the carbon loop, recycle carbon dioxide and lead to improved environmental outcomes.

Find out more about our research to improve carbon anodes by reading Anode coating reduces air burn. 

  • Article originally appeared in Process February 2007.