Oxalic acid

Oxalic acid (CAS 144-62-7) is a dicarboxylic organic acid used as a reducing agent, chelating agent, and pH regulator in industrial processing.

Where is Oxalic acid used?

• Water treatment and industrial cleaning: dissolves iron oxide and rust deposits from boilers, heat exchangers, and pipework
• Textile and paper: bleaching and stripping agent that removes discoloration from natural fibers and pulp
• Mining and hydrometallurgy: precipitates rare earth elements and other metals from leach solutions
• Personal care: pH adjuster and chelating agent in hair bleaching and skin-lightening products
• It removes metal ions and mineral deposits from surfaces and process streams.
• Used in leather processing.
• Used to make pigments, inks, dye fixatives for wool, and fabric bleaches.
• Used in water treatment to remove heavy metals and impurities.
• Used in organic and conventional beekeeping for Varroa control.
• Used for the precipitation of metals such as gold, silver, copper and mercury.

Formulation notes

• Attacks certain types of plastic.
• For rust removal on metal machinery parts, soak in a solution of ten parts water to one part oxalic acid.

Typical specification

• ACS Grade has an assay specification of 99.5-102.5%.
• ACS Grade has a maximum heavy metals content of 5 ppm.
• Dihydrate form has CAS number 6153-56-6.

Regulatory status

• Has the EU index number 607-006-00-8.
• Has the UN number 3261.
• Classified as harmful if swallowed (H302) under the harmonised CLP classification.
• For transport, classified under UN Class 8 with packing group III.
• The harmonised classification must be supplemented by the supplier through self-classification where applicable.

Storage, packaging and handling

• Reacts with some silver compounds to produce explosive silver oxalate.
• Should be stored separately from strong oxidants, food and feed; keep dry and well closed.

Technical content is compiled and updated by the SoleChem product team from public technical sources; the certificate of analysis (COA) governs product-specific specifications.