Aluminum mining waste could be a source of green steel
arstechnica.com
arstechnica.com
Iron is produced in 2 ways: from scrap iron (i.e. recycling) or from iron ore. If produced from iron ore, the ore needs to contain about 50-60% iron to be economically viable. It goes without saying that in this context we are talking about regular smelting, using coal. That generally happens away from the mines, which is a sign that the capital cost is high; if it weren't they'd build the furnaces right next to the mines to reduce transportation cost.
Let's forget about hydrogen or green steel. Can you just start using the "red mud" as iron ore? Very unlikely. You'd need to either move the furnace next to the aluminum mine, or bring the red mud to the furnace. The first is not an option. The steel industry is so cutthroat with margins so low, that you need scale. Huge scale. Aluminum is produced in tiny quantities compared to iron, there's no way you'd have enough scale to justify a steel furnace next to an aluminum mining operation. Bringing the red mud to the furnace is not really an option either: you would need to at a minimum dry it out somehow to make it solid, otherwise the transportation costs balloon. But this red mud is supposedly quite toxic, it does not appear to be so straightforward to dry it out, and that would add to the processing cost too.
And then the hydrogen thing. Let's first focus on transitioning the regular steel making to hydrogen. This in itself appears to be an extraordinarily hard nut to crack. If we manage it, it's a huge win. We can then expand to aluminum waste cleanup if we want, after we pop some champagne. But let's stay focused on regular green steel first.
> But the key feature of this is the extremely low carbon emissions.
The process is quite dependant on a clean energy source if the ‘low carbon emissions’ thing is to be claimed.
Their method relies on hydrogen and electricity, which can both be sourced from renewable power and extracts iron and potentially other metals from the waste. What's left behind may still be toxic but isn't as environmentally damaging.
Rio Tinto and Sumitomo to build Gladstone hydrogen pilot plant to trial lower-carbon alumina refining
https://www.riotinto.com/en/news/releases/2023/rio-tinto-and...
The project will consist of construction of a 2.5MW on-site electrolyser to supply hydrogen to the Yarwun refinery and a retrofit of one of Yarwun’s four calciners so it can operate at times with a hydrogen burner.
The trial is expected to produce the equivalent of about 6,000 tonnes of alumina per year while reducing Yarwun’s carbon dioxide emissions by about 3,000 tonnes per year.
Converting the entire plant to green hydrogen could reduce emissions by 500,000 tonnes per year, which is the equivalent of taking about 109,000 internal combustion engine cars off the road.
https://www.manmonthly.com.au/rio-tinto-driving-development-...
Rio Tinto is aiming to drive development of Australia’s largest solar power project near Gladstone, after agreeing to buy all electricity from the 1.1GW Upper Calliope Solar Farm to provide renewable power to Rio Tinto’s Gladstone operations.They're not markedly worse than run of the mill (for all their extreme f-ups in some places they have years of "as expected" somewhere else).
My cousin has just exited New Zealand to work here thanks to (non Rio Tinto) Oil & Gas extracters going bankrupt and leaving the NZ taxpayer with a clean up bill.
To clarify, that's the NZ-local operating arm of an international O&G energy Co. going locally bankrupt in NZ, not the parent company.
That sucks.
I blame the NZ Govt. (my apologies) for not getting up front { deposits | guarentees | meaningful bonds } to cover exit and rehabilition costs (which I understand they have recently introduced legislation to do so in future).
All Corporations are Crooks! (in the sense that they will, at most, do the least they can).
All that typed, here at least Rio is on the up and up in so far as they are in fact trialling solar power, hydrogen generation, and many things that are making running costs cheaper for Rio Tinto along with increased profits.
Oddly mining resource companies running huge billion tonne per annum truck fleets are pushing for green hydrogen as a night time buffer for daytime solar in order to save money in the longer term.
By sinking a billion or so into massive solar farms and hybrid truck fleets they save in the long run by paying less for energy to third parties (the Chevron, Exxon, et al. crowd).
These are the company statements made to stockholders by the likes of Rio Tinto, Fortescue Metals, and others .. so they carry the weight of legally binding statements of intent at least.
Still looking at a ten year transition, of course, but these a massive consumers of fossil fuel energy that are moving now to use renewables.