Zirconium Hydroxide: Zircon Fused with Potassium Bisulphate, then Caustic Soda in Silver (Roscoe 1913)

Zircon is opened without hydrofluoric acid: a bisulphate fusion leaves basic zirconium sulphate, a caustic soda fusion in silver turns it to zirconia, and the zirconia is dissolved in sulphuric acid and thrown down with ammonia. Result: white zirconium hydroxide, the start of the zirconium chain. Source: Roscoe and Schorlemmer, A Treatise on Chemistry vol. 2 (1913), pp. 823-824. Not given: amounts and times. Picture drawn by Youblob.