Yesterday I received an email from Jim, who is one of the best commodities analysts around (I won’t name him fully, in case it goes to his head). He wanted to confirm what the average pot life is in China, especially for plants that have been around longer than 7 - 10 years.
His question got me thinking.
Many years ago, when I joined Tomago Aluminium as their Raw Materials Manager, just as we were completing my contract negotiations, the plant manager said to me, “Oh by the way, you will also be responsible for SPL.” At that time, I didn’t know how to even spell SPL… A couple of years later, I found out in no uncertain terms, as we shipped several thousand tons of Spent Pot Linings to Italy for processing, along the way spending something like $800 per ton. SPL is a dangerous and hazardous item, with hydrogen, cyanide, arsenic and other nasties.
Now let’s look at the situation in China. Jim reckons the average pot life is about 5 years in China. If we take a 5-year average of total metal production, and use 2 tons per day output, we can roughly estimate the amount of SPL that China produces each year. Let’s assume for this calculation that the average metal production per year has been 15 million tons. That means 41,000t per day, so approximately 20,000 pots in operation at any one time over the last 5 years. If the average life is 5 years, then we can expect that 4,000 pots have been delined and relined per year in that time. Assuming 20t of materials per pot to come out (cathode blocks, refractory materials, sidewalls, etc) then that means that China is generating roughly (very roughly) about 80,000t of SPL per year.
Even if I am 50% out in my calculations, that’s still 40,000t of nasty material that’s probably going into landfill or road base.
SPL is a problem by-product for the world’s aluminium industry. Western companies such as Alcoa have been working on technology solutions for removing the dangerous elements and converting the material into some for of re-usable product, but I shudder to think how the Chinese industry must be dealing with it here. I hope my fears are unfounded.