METHOD FOR RECOVERING METALS

• Main Authors: KARI VALKAMA, TUUKKA KOTIRANTA
• Format: Patent
• Language: English
• Published: 25.05.2016

The invention relates to a method and apparatus for recovering metals from metalliferous starting materials comprising steps of i) leaching the metalliferous starting material in chloride-based leaching liquor, ii) withdrawing from the leaching step i) aqueous chloride solution with dissolved metals, iii) recovering metal value from the aqueous chloride solution in a metal recovery process step, iv) neutralizing hydrogen chloride content of the aqueous chloride solution in the metal recovery process step with adding hydrolyzed ammonia to the process solution so as to form ammonium chloride, v) withdrawing ammonium chloride containing process solution to an ammonium regeneration step where calcium-containing reagent is added to generate calcium chloride and ammonia gas and recycling ammonia back to the metal recovery process step iii), vi) regenerating the CaCl2-solution with H2SO4 so as to provide a aqueous HCl solution for recycling to the leaching step i).