Spent Potlining Challenges

Spent Potlining is particularly hazardous due to:

• Its propensity to combine with water and generate explosive gases
• The presence of cyanide at toxic levels.

Spent Potlining is regulated as a hazardous waste in most parts of the world and is subject to:

• The Basel Convention on the Control of Trans-boundary Movements of Hazardous Wastes and their Disposal
• Increasingly onerous regulatory requirements when shipped beyond the smelter
• Bans on landfill in an increasing number of countries.

Spent Potlining Characteristics

The aluminium reduction cell, or “pot” contains a lining of refractory and carbon blocks and bricks that contains the hot cryolite and metal at around 970 degrees centigrade. Over time this lining is worn away and impregnated with chemical compounds. Once the refractory and carbon lining has reached the end of its useful life the pot is taken out of service and the lining removed as Spent Potlining.  In its raw form, Spent Potlining varies in size from fine dust to lumps of up to one metre. It is typically made up of a wide range of minerals and chemical compositions because the different materials in the Potlining are mixed together during removal from the pot.

Spent Potlining and the Primary Aluminium Industry
For more than twenty years, the primary aluminium and support industries have invested significant capital into the research and development of Spent Potlining solutions with limited success.

Potential Spent Potlining solutions have been hampered by their tendency to:

• Be capital intensive with high operating costs
• Present unproven process technology with significant technical risk, resulting in many project failures
• Produce relatively large quantities of residual waste material of little or no value.

Regain has solved these problems with a low cost, proven technology with no residual waste material.