Aluminum hydroxide

Aluminum hydroxide (CAS 21645-51-2), also sold as hydrated alumina, is an inorganic mineral compound used as a flame retardant, antacid active, and catalyst precursor. Also marketed as Amphojel.

Where is Aluminum hydroxide used?

• Plastics and polymer compounding: halogen-free flame retardant and smoke suppressant
• Cable jacketing, flooring, and construction panels for fire safety standards
• Pharmaceuticals: active ingredient in antacid formulations that neutralizes excess gastric acid
• Paper and textile industries: mordant and surface treatment agent improving dye fixation and coating adhesion
• Catalyst producers use it as a precursor for alumina-based catalysts in refining and chemical synthesis.

Good to know: Its function shifts significantly by grade and particle size, making specification alignment critical at the sourcing stage. Standard grades include USP and BP for pharmaceutical use, and technical or flame-retardant grades for industrial polymer applications.

Commercial specifications

• Particle size and surface area vary by intended application