Untersuchung des Reduktionsverhaltens einer Pb/Zn-haltigen Schlacke

Research output: ThesisMaster's Thesis

Organisational units

Abstract

Most of the current metallurgical processes cause considerable proportion of residues to be landfilled. This thesis is focused on the feasibility of using a pyro-metallurgical process to recycle a primary lead-zinc-slag. Metals such as lead, zinc and iron should be recovered as completely as possible and the remaining slag, free of heavy metals, should be used as raw material in the construction industry. On the one hand, the environmental load is reduced as primary raw materials and landfill capacities are preserved, and on the other hand the valuable metals should be returned to the production cycle. As reducing agent and collector reagent raw iron in a temperature range between 1280 and 1500 °C is used. Elements such as zinc, lead, iron, sulfur and arsenic are reduced from the slag completely or to a high rate at least. Zinc and lead evaporate at the applied conditions at the start of the process and can be reclaimed from the exhaust gas. Due to the kinetics the best results are achieved at temperatures of 1500 °C. Here, the lowest iron content in the residual phase is obtained. The lower limit for the feasibility of the process is about 1280 °C, since the raw iron is no longer completely liquid and therefore limits the velocity of the reduction process. Furthermore, the slag basicity in terms of the CaO/SiO2 ratio is varied from 0.65 to 1.6. The higher basicity – based on additionally fed CaO – leads to an inhibited removal of the sulfur in the slag. The results show that the zinc containing dust out of the exhaust gas can be considered as a saleable product. The produced iron alloys are suitable for the use as raw material in the production of reinforced steel. The residual heavy metal free phase could be used in the building material industry considering the chemical analysis.

Details

Translated title of the contributionInvestigation of the reduction behavior of a Pb/Zn-slag
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
Supervisors/Advisors
Award date25 Oct 2019
Publication statusPublished - 2019