Used as a coagulant in water and wastewater treatment to remove impurities and suspended particles. Effective in clarifying drinking water by promoting the aggregation of fine particles for easier filtration. Employed in dyeing and tanning industries as a mordant to fix dyes and improve color fastness on fabrics. Acts as an etching agent in lithography and printmaking processes. Utilized in analytical chemistry as a reagent for various precipitation reactions and qualitative tests (e.g., for thiocyanates or phosphates). Also found in some antiseptic and astringent formulations for minor skin irritations.