Feb 2025
New Zealand Aluminium Smelters Ltd is ultimately owned by Rio Tinto and operates an aluminium smelter at Tiwai Point adjacent to Bluff at the very bottom of New Zealand’s South Island.
The smelter’s owner is investigating the building of a processing plant at the smelter to deal with a highly toxic byproduct of their smelting process known as “Spent Cell Liner”. The byproduct is currently stored and buried on-site in a Tiwai Point landfill and it contains hazardous substances including cyanide and fluoride. If this byproduct is exposed to water, it can potentially generate toxic and explosive gases including hydrogen, methane and ammonia etc. There is presently 217,000 (two hundred and seventeen thousand tonnes) held at Tiwai Point. This mass of crap is considered to be one of the largest hazardous waste stockpiles in Australasia.
Spent Cell Liner was listed by the United States Environmental Protection Agency in 1988 as a hazardous waste and in New Zealand it is a Hazardous Material Grade 6. It represents a major environmental concern.
In 2022 it was estimated that clean-up costs at the smelter would have been in the region of NZ$687 million and three years later it will be hugely more than that.
Industry sources indicate the Tiwai Point smelter generates about 8000 tonnes of Spent Cell Liner a year based on a smelted aluminium production of approximately 330,000 tonnes.
Rejigit wrote in June 2024 about the preferential electricity price Tiwai Point smelter had negotiated; https://rejigit.co.nz/vendor/article.php?uid=li