Ammonium chloride slag treatment for zinc - chloride prodn

摘要

Ammonium chloride slags of various origin and degree of hydrolysis, esp. for production of ZnCl2, are processed by (a) mixing raw materials in such proportion that ZnCl2 is converted to Zn-NH4 chloride and Zn oxychloride and (b) crushing to 3-30 mm. particles, finer particles being recycled to (a) and coarser ones to (b), then (c) lixiviating with soln. containing ZnCl2 and NH4Cl with concentration falling from 30 to 5% and temp. rising from 28 to 80 degrees C by (d) forcing liquor through material from bottom of vessel and removing after 5-60 min. contact time and (e) reversing liquid flow. Process gives valuable soln. containing ZnCl and NH4Cl and residue of NH4Cl-free Zn(OH)2 or oxychloride, suitable for producing pure ZnCl2.