Ferric Alum vs Non-Ferric Alum: Which Coagulant is Right for Your ETP?

Ferric alum carries iron (typically 0.3–0.5% Fe), so crystals look yellow to brown and unit cost stays lower.

Non-ferric alum is refined below ~0.004% Fe — white crystals for colour-critical jobs.

Both are aluminium sulphate coagulants used in water treatment, paper sizing and industrial clarification.

You pay more for non-ferric because of the extra purification — not because the aluminium chemistry is magically different.

Ferric alum coagulates well on most ETPs but can leave a yellow tinge at high dose or low pH.

Non-ferric is preferred for potable water, paper mills and textile finishing where iron staining rejects the batch.

Keep coagulation pH roughly 6.5–7.5; ferric may need a touch more lime because of iron hydroxide.

Ferric sludge volume is a bit higher — that shows up on belt-press hours at large plants.

Pick ferric alum for general industrial ETP when discharge colour already passes and iron is not a product risk.

Specify non-ferric for drinking water, paper, pharma process water and food-adjacent lines.

Ask for COA iron %, Al₂O₃ and insolubles before the PO — not after the truck arrives.

Count sludge disposal in the cost sheet; a “cheaper” ferric bag can cost more once you press and dispose.

Drashti Chemicals stocks related industrial chemicals from Vadsar with batch COA, MSDS and GST invoicing (24AGLPC6288M1ZX). We are a supplier/stockist — share grade and quantity for a documented bulk quote. No public list prices.