US 12,448,666 B2
Sustainable method for recycling smelting works dusts and sludges to produce iron-containing, heavy-metal-depleted reclaimed materials with recovery of lead and zinc
Andreas Tebeck, Rheurdt (DE); and Eckhard Pappert, Lünen (DE)
Assigned to ThyssenKrupp Steel Europe AG, Duisburg (DE)
Appl. No. 17/798,709
Filed by ThyssenKrupp Steel Europe AG, Duisburg (DE)
PCT Filed Feb. 25, 2021, PCT No. PCT/DE2021/100193
§ 371(c)(1), (2) Date Aug. 10, 2022,
PCT Pub. No. WO2021/170181, PCT Pub. Date Sep. 2, 2021.
Claims priority of application No. 102020202575.4 (DE), filed on Feb. 28, 2020.
Prior Publication US 2023/0295765 A1, Sep. 21, 2023
Int. Cl. C22B 1/08 (2006.01); C22B 1/24 (2006.01); C22B 1/26 (2006.01); C22B 3/00 (2006.01); C22B 19/30 (2006.01); C25C 1/16 (2006.01); C25D 3/22 (2006.01)
CPC C22B 1/08 (2013.01) [C22B 1/2406 (2013.01); C22B 1/26 (2013.01); C22B 19/26 (2013.01); C22B 19/30 (2013.01); C25C 1/16 (2013.01); C25D 3/22 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A regeneration process for producing iron-containing heavy metal-depleted secondary raw materials and recovering lead components and zinc components from at least one of metallurgical plant dust and sludge, comprising the steps of:
I) providing a first starting material which comprises at least one of iron, zinc, and lead, and a second starting material containing at least one chlorine component,
II) mixing the first starting material with the second starting material, transferring the mixture to an oven unit, and subsequently pelletizing it,
III) drying the mixture with expulsion of steam, and subsequently pelletizing it,
IV) reacting zinc, lead and further heavy metal components and chlorine components by pyrolysis,
V) capturing the gas phase from the pyrolysis from step IV) in sulfuric acid, with cooling,
V-a1) subsequent to step V) the sulfuric acid solution containing Zn in the form of ions is transferred to a further vessel and heated for removing residual chloride until the sulfuric acid fumes off,
V-a2) the sulfuric acid solution containing Zn in the form of ions from step V-a1) is cooled and transferred to a container with water, sulfuric acid and metallic zinc,
V-c1) PbSO4 from step V) is taken off as a solid,
VI) providing the pyrolysis residue which remains as an iron-containing secondary raw material depleted in zinc, lead and further heavy metal components.