Spent Potlining (SPL) is a waste material generated in the primary aluminium smelting industry.
[4] Production of primary aluminium metal with the Hall–Héroult process involves the electrolytic reduction of alumina in cells or pots.
[5] Due to the concentrations of fluorides and cyanides in spent potlining, and the tendency to leach in contact with water, the US Environmental Protection Agency (USEPA) listed the materials on 13 September 1988 (53 Fed.
This must change if the aluminium industry wants to claim a reasonable degree of sustainability and environmentally tolerable emissions.
[12] There is variation in composition of SPL depending on such factors as the type of aluminium smelting technology used, the initial components of the cell lining and dismantling procedures.
Observed effects on vegetal cells included reduction in mitotic index and an increase in the frequency of chromosome alterations.
The observed effects induced by SPL suggest its mutagenic potential on plant and animal cells, confirming its noxiousness to the environment and human beings.
Lee and Jones-Lee describe the evolution and technical aspects of “dry-tomb” landfilling and why they consider it a seriously flawed technology citing problems such as: A 2004 study of a landfill containing SPL located in North America identified four chemical species as priority contaminants: cyanide, fluoride, iron and aluminium.
Life-cycle assessment and ground water transport modelling were used to provide an understanding of the situation identifying environmental issues and significant ecotoxilogical potential impacts.
The study observed that, while assumptions that the confinement of soil and waste was assumed to be perfect, in fact these sites could themselves become sources of contamination.
The study states that the most advantageous option is the total destruction of the SPL fraction if concerns about the quality of long term confinement are considered.
DE-5698 between the Port of Tacoma and the Washington State Department of Ecology addresses the removal, through excavation and offsite disposal, of SPL zone material and associated contaminated soil at an old aluminium smelter site.
[6][17] The Arkansas Pollution Control and Ecology Commission noted that treated SPL used to construct roads was recovered and placed in secure landfill.