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Aluminium potassium sulfate dodecahydrate (alum) is a naturally occurring mineral that has been used in a multitude of applications from printing to electrolytic copper plating.
A 1777 (OTTO) Aluminium potassium sulphate, GR 99.5% Cas 7784-24-9 - used in water purification, leather tanning, dyeing, fireproof textiles.