Method and system for ash treatment

A method for treatment of combustion ash for metal recovery, the method comprising the steps of:

• a) heating a continuous flow-through furnace to a first temperature,
• b) feeding a combustion ash into the continuous flow-through furnace,
• c) feeding oxidizing gas through the continuous flow-through furnace,
• d) heating the combustion ash fed into the continuous flow-through furnace in the first temperature for volatilizing chlorides contained in the ash, and removing the chlorides, wherein removing the chlorides is performed in a first rotary kiln furnace, and wherein, after removing the chlorides is performed, the combustion ash is fed to a second rotary kiln furnace for performing step f),
• e) changing the conditions in the continuous flow-through furnace by feeding a reducing gas flow through the continuous flow-through furnace,
• f) changing the temperature of the continuous flow-through furnace to a second temperature for heating the combustion ash in the furnace for volatilizing one or more metals contained in the ash into the gas flow, and
• g) recovering the vaporized particles in one or more collection units.