2. Industrial oxalic acid as reducing agent: mainly used in organic synthesis industry to produce hydroquinone, pentaerythritol, cobalt oxalate, nickel oxalate, gallic acid and other chemical products.
3. Industrial oxalic acid as mordant: ammonium ferric oxalate is a reagent for printing blueprints.
4. Industrial oxalic acid can remove rust: oxalic acid can be used to remove rust. After the skin comes into contact with oxalic acid, it should be washed with water in time.