Leaching weathered olivine
Facts checked 1 Nov 2026
Leaching dissolves Weathered Olivine in Sulfuric Acid and splits it into eight different products, among them the Iron Oxide you'll make iron from. You'll run it in rounds, each one using the acid the round before gave back.
The recipe
The process is called Olivine Acid Leaching and Calcining. For every 15,422 kg of Weathered Olivine and 12,946 kg of Sulfuric Acid, it makes Sulfur Dioxide, Carbon Dioxide, Oxygen, Deionized Water, Iron Oxide, Zinc Oxide, Nickel Oxide, and Magnesia.
Make Sulfur Dioxide the primary output
You're after the Iron Oxide, so it's tempting to make that the primary output. Don't. Choose Sulfur Dioxide instead:
- All the Sulfur Back: As the primary output, Sulfur Dioxide comes out in full, and that's exactly enough to make every tonne of acid again.
- Iron Oxide Still Comes: The Iron Oxide comes out as a by-product at 62.5%, thanks to your Scientist. You'll run a few more rounds to get enough, but you never have to buy more acid.
One round
With 2,000 tonnes of acid, one round looks like this:
- In: About 2,380 tonnes of Weathered Olivine and 2,000 tonnes of Sulfuric Acid.
- Primary Output: About 1,310 tonnes of Sulfur Dioxide.
- By-products: About 180 tonnes of Iron Oxide, 560 tonnes of Carbon Dioxide, 370 tonnes of Magnesia, 230 tonnes of Deionized Water, 190 tonnes of Oxygen, and about 45 tonnes each of Zinc Oxide and Nickel Oxide.
- Time: About six and a half hours, nearly three of them set-up.
Over four or five rounds you'll leach all your Weathered Olivine and collect about 755 tonnes of Iron Oxide: enough for the warehouse's steel.
Start a round
- Select an Academy refinery and click Refine Materials.
- Choose Olivine Acid Leaching and Calcining, with your crew's warehouse for the inputs and outputs.
- Select Sulfur Dioxide as the primary output.
- Set the amount to use the acid you have, check the time, click Lease & Begin, and approve.
When it's done, click Finish. Then turn the Sulfur Dioxide back into acid, in the next lesson, and start the next round.