Ferric Nitrate: Scrap Iron Dissolved in Concentrated Nitric Acid (Thorpe 1912)

Ferric nitrate is an iron salt used as a dyeing mordant and as a source of pure iron oxide. Concentrated nitric acid dissolves scrap iron, and the solution crystallises as hydrated ferric nitrate. Source: Thorpe, Dictionary of Applied Chemistry vol. 3 (1912), Iron. Not given: amounts or heat. Adding the iron slowly, filtering and evaporating are ours. Concentrated nitric acid gives off choking red fumes: fume hood, goggles and gloves. Picture drawn by Youblob.