Water, salts, and calcium
Facts checked 1 Nov 2026
Your Water does two jobs. Purified, it becomes the Deionized Water the acid loop and the cement need. And the salts left behind hold a little Calcium, just enough to turn your iron into steel. Three short processes, one after another.
Step 1: Purify the water
Water Vacuum-evaporation Desalination turns every 20 kg of Water into 19 kg of Deionized Water and 1 kg of Raw Salts. Choose Deionized Water as the primary output: you need lots of it, and only a little of the salts.
- In: About 1,000 tonnes of Water.
- Out: About 950 tonnes of Deionized Water and 31 tonnes of Raw Salts.
- Time: About 3 hours.
Keep the Deionized Water: about 600 tonnes go into the acid loop, and 250 tonnes into the cement.
Step 2: Separate the salts
Salt Selective Crystallization splits Raw Salts into six different salts. The one you want is Calcium Chloride, so make it the primary output. The rest, mostly Sodium Chloride and Potassium Chloride, are by-products you can sell.
- In: About 30 tonnes of Raw Salts.
- Out: About 1.5 tonnes of Calcium Chloride, plus the other salts.
- Time: About 3 hours, nearly all of it set-up.
Step 3: Make Calcium
Calcium Chloride Molten Salt Electrolysis splits Calcium Chloride into Calcium and Chlorine. Choose Calcium as the primary output.
- In: About 1.5 tonnes of Calcium Chloride.
- Out: About 0.55 tonnes of Calcium, plus some Chlorine.
- Time: About an hour.
Half a tonne of Calcium is all the steel needs. Keep it safe until the Steel and Cement course.
Running them
Each step uses what the one before made, so they run in order, but all three together take only about seven hours. Start them while the weathering and the oxygen jobs are running, using Refine Materials on an Academy refinery and Lease & Begin as before, and remember to set the primary output each time.