Sustainable method for recycling smelting works dusts and sludges to produce iron-containing, heavy-metal-depleted reclaimed materials with recovery of lead and zinc

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.