US 12,281,372 B2
Method and system for ash treatment
Jorma Jokiniemi, Vantaa (FI); Daniel Lane, South Australia (AU); Anna Lähde, Toivala (FI); and Olli Sippula, Kuopio (FI)
Assigned to BETOLAR OYJ, Kannonkoski (FI)
Filed by BETOLAR OYJ, Kannonkoski (FI)
Filed on Aug. 26, 2021, as Appl. No. 17/445,998.
Application 17/445,998 is a continuation of application No. PCT/FI2020/050027, filed on Jan. 16, 2020.
Claims priority of application No. 20195150 (FI), filed on Feb. 28, 2019.
Prior Publication US 2021/0388463 A1, Dec. 16, 2021
Int. Cl. C22B 7/02 (2006.01); C22B 7/00 (2006.01)
CPC C22B 7/02 (2013.01) [C22B 7/001 (2013.01)] 17 Claims
OG exemplary drawing
 
1. 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.