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Aluminum’s Long Tail: Once only a dangerous waste, Red Mud is finding new purpose.
Aluminum (or Aluminium for everyone else in the world) is a wonderful metal that’s infinitely recyclable. One aluminum soda can weighs about 15 grams (about 0.5 oz), with something like 66 cans or so in a kilogram (around 32 cans in a pound). This aluminum is refined from an ore called Bauxite that is mined from the ground, from which aluminum oxide (Alumina) is extracted chemically using sodium hydroxide in the “Bayer Process”. The Alumina goes on to be electrolytically smelted into aluminum. The rest? The leftovers are called “Bauxite Residue.” For every kilogram of aluminum out in the world, somewhere there’s a kilogram (or more!) of Bauxite Residue. Somewhere. In great big heaps, or massive lagoons, or even mountains. In years past, it was even been dumped into the ocean.
Bauxite Residue earned the name “Red Mud” due to its rich red color from a high percentage of iron oxides, and traditionally collected in large lagoons like many other types of mining tailings. Rainwater keeps the dust down, but creates a slurry of mud that must be managed. The mud is caustic (with a pH approaching drain-opener like Draino or Liquid Plumber), and … doesn’t do much but sit there and wait for something to go wrong.
