Instead, Boston Metal uses an electro-chemical process called molten oxide electrolysis.The technique passes electricity through iron oxide mixed with a slew of other oxides, which are chemical compounds that contain at least one oxygen atom. If the electricity that goes into the process is clean, then the steel that comes out the other side of the electrolysis cell is clean, too.
"What's special about it is it can survive and high temperature — 1,600 Celsius, 3,000 Fahrenheit. And as you're doing electrolysis, you're using electrons to split apart iron and oxygen. So that anode is getting hit by oxygen all day long at super high temperature, and it has to survive in that environment," explained Rauwerdink during a tour of the lab. "There's very few elements that will do that. That alloy is one that will.
Also, the electrolysis cells can get bigger to a certain point, but after that the company will have to place many cells next to each other to make green steel.This is a mid-size electrolysis device, between the lab scale bench and the full-scale cell. This can run for weeks at a time and gathers performance data for the anode. "If you go to a full-scale plant using this technology, you might see a couple of 100 electrolysis cells." Rauwerdink told CNBC.