Aluminium sulfate (commonly available as the 14-, 16-, or 18-hydrate forms) is a white crystalline inorganic salt widely used for its powerful coagulating and flocculating action. It is a staple in water and wastewater treatment, where it aids in turbidity reduction and contaminant removal.

Beyond purification, it plays a central role in paper sizing, dyeing and printing processes, leather tanning, and as an acidity regulator in various industrial formulations.

These hydrate variants differ mainly in their bound water content but deliver similar functional performance; selection is typically based on handling preference, solubility needs, and process requirements. Purity and impurity Technical Data should be matched to the end-use, especially for applications requiring analytical or high-grade material.

It is widely employed as a reagent in nickel determination methods, in electroplating baths, and in the preparation of nickel-containing catalysts and coordination compounds. The material is also used in certain dyeing and finishing processes where nickel complexes play a functional role.
The selection of grade should be based on impurity limits and the nickel(II) sensitivity of the end application, especially for analytical or high-purity chemical work.