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A $225-million pilot plant for treating spent potlining has been completed in Quebec’s Saguenay region, according to Rio Tinto Alcan. The project was outlined by the former Alcan Inc. late in 2006 as a new approach to treating about 80,000 metric tons/year of SPL generated by the group’s primary aluminum plants in the region.
“Potlining” is the conductive carbon material used to line the electrolytic cells in which primary aluminum is separated from alumina. Because SPL contains trace amounts of cyanide and some lead, chrome, and other heavy metals (primarily lead and chrome), along with sodium and fluoride, it is considered a hazardous waste in large quantities. Rio Tinto Alcan states its new process offers a “sustainable solution” for treating the material, and adds it will yield by-products that will be reused in alumina refining. The company adds that research will continue into other by-product applications.
The Rio Tinto Alcan process was pioneered by the group’s Arvida Research and Development Centre (ARDC) prior to Alcan’s acquisition by Rio Tinto Ltd. Rio Tinto Alcan indicates that the new plant’s pre-operational checks and pre-commissioning will be complete in time for production-scale operation in April.
“We are very pleased that the project is on time and on budget,” stated Jacynthe Ct, president/CEO of Rio Tinto Alcan’s Primary Metal business unit. “Rio Tinto Alcan is proud to have developed an environmentally sustainable, innovative, and economically competitive solution for treating potlining. It may well become the industry standard. In collaboration with its partners, we will continue research aimed at full recycling of the by-products generated by the process.”
