Difference Between Ferric and Non Ferric Alum | Grade

Ferric alum (ferrous alum) contains iron (Fe) as an impurity, typically 0.3–0.5% Fe, giving it a yellowish to brownish appearance.

Non-ferric alum is refined to iron content below 0.004%, producing a white crystalline product suitable for colour-sensitive applications.

Both grades are aluminium sulphate (Al2(SO4)3·18H2O) coagulants used in water treatment, paper sizing and industrial effluent clarification.

Ferric alum is significantly lower in cost and widely available; non-ferric alum commands a premium due to additional purification steps.

Ferric alum coagulates effectively in most ETP applications but can impart a yellow tinge to treated water at high doses or low pH.

Non-ferric alum is preferred for potable water, paper mills and textile finishing where iron staining would reject the final product.

Both grades require pH adjustment to 6.5–7.5 for optimal coagulation; ferric alum may need slightly more lime due to iron hydroxide formation.

Sludge volume from ferric alum is marginally higher due to iron hydroxide precipitation, increasing sludge handling costs in large plants.

Use ferric alum for general industrial ETP coagulation where discharge colour limits are met and product quality is not iron-sensitive.

Specify non-ferric alum for drinking water plants, paper mills, pharmaceutical process water and food-grade applications.

Request batch COA showing iron content, Al2O3 percentage and insoluble matter before placing bulk orders.

Evaluate total cost including sludge disposal — non-ferric alum may reduce downstream treatment costs despite higher per-kg unit cost.

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.