Spent Potliner Challenges

Spent Potliner is particularly hazardous due to:

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

Spent Potliner 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 Potliner Characteristics

The aluminum 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 Potliner.  In its raw form, Spent Potliner varies in size from fine dust to lumps of up to one meter. It is typically made up of a wide range of minerals and chemical compositions because the different materials in the Potliner are mixed together during removal from the pot.

Spent Potliner and the Primary Aluminum Industry
Over more than twenty years, the primary aluminum and support industries have invested significant capital into the research and development of Spent Potliner solutions with limited success.

Potential Spent Potliner 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.