Production of Metallic Zirconium and Hafnium

All these difficulties require that chemicals for producing these metals be exhaustively purified, especially of oxygen, water, and nitrogen, and limit the number of processes that can be used. 

The principal processes that have been used for producing zirconium and hafnium metal of the requisite purity are as follows  

The Kroll process, involving reduction of tetrachloride vapor by molten magnesium 

The hot-wire process, involving thermal decomposition of the iodide 

Electrolysis of the double potassium fluoride dissolved in fused salts 

---

The most important commercial methods of production of metallic zirconium and hafnium are based on furnace reduction, either of MCI4 with magnesium or a Na-Mg mixture (the Kroll process), yielding a metal sponge, or of metal fluorides with Ca at 2000 °C to give an ingot. The... 

---