TY - THES

T1 - Characterisation of anode slimes with regard to a multi-metal recovery

AU - Otto, Christoph

N1 - embargoed until 25-10-2022

PY - 2017

Y1 - 2017

N2 - The current diploma thesis deals with the possibilities of the processing of anode slimes from the copper refining electrolysis with regard to an efficient recovery of the contained metals. The focus was laid on the tramp elements Sn, As and Sb, as they disturb the further recyling on the one hand, and are reusable on the other hand, as long as they can be extracted in a pure form. The literature survey gives an overview of the residues occurring in the production and recycling of copper. The anode slime is dealt with in more detail, especially its formation during the electrolysis. Furthermore, an excerpt of compositions of anode slimes from different copper plants worldwide and a summary of phases detected in anode slimes by researchers in the past are presented. The principles of the measuring methods used within this diploma thesis are briefly described. The state of the art in the recycling of anode slime is sketched, and subsequently, selected pyro- and hydrometallurgical processes are introduced, which are currently applied or investigated for the pretreatment of anode slimes. The first part of the experimental work dealt with the detailed characterisation of two anode slime samples using chemical analysis, XRD, SEM-EDX and stoichiometric calculations following the literature survey. The local coexistency of different elements was investigated and at the end it was possible to identify some of the phases visible in the SEM images. Tentative trials on the leaching of Sn, As and Sb from anode slime in aqueous KOH-solution represented the second part. The experimental layout was intentionally kept simple with regard to energy efficiency, i.e. atmospheric pressure and moderate temperatures. In the course of the experimental series the temperature was varied in the range between ambient temperature and 80 °C and the solid/liquid ratio between 1/4 and 1/20. The highest yield of all three elements could be achieved at 80 °C with a solid/liquid ratio of 1/20, where over 80 % of the As and Sn contained as well as nearly 40 % of the Sb contained was leached. Moreover, the temperature control was recognised as a crucial step within the process, and at the end proposals for further optimisation are presented, with special focus on the separate leaching of As and Sb.

AB - The current diploma thesis deals with the possibilities of the processing of anode slimes from the copper refining electrolysis with regard to an efficient recovery of the contained metals. The focus was laid on the tramp elements Sn, As and Sb, as they disturb the further recyling on the one hand, and are reusable on the other hand, as long as they can be extracted in a pure form. The literature survey gives an overview of the residues occurring in the production and recycling of copper. The anode slime is dealt with in more detail, especially its formation during the electrolysis. Furthermore, an excerpt of compositions of anode slimes from different copper plants worldwide and a summary of phases detected in anode slimes by researchers in the past are presented. The principles of the measuring methods used within this diploma thesis are briefly described. The state of the art in the recycling of anode slime is sketched, and subsequently, selected pyro- and hydrometallurgical processes are introduced, which are currently applied or investigated for the pretreatment of anode slimes. The first part of the experimental work dealt with the detailed characterisation of two anode slime samples using chemical analysis, XRD, SEM-EDX and stoichiometric calculations following the literature survey. The local coexistency of different elements was investigated and at the end it was possible to identify some of the phases visible in the SEM images. Tentative trials on the leaching of Sn, As and Sb from anode slime in aqueous KOH-solution represented the second part. The experimental layout was intentionally kept simple with regard to energy efficiency, i.e. atmospheric pressure and moderate temperatures. In the course of the experimental series the temperature was varied in the range between ambient temperature and 80 °C and the solid/liquid ratio between 1/4 and 1/20. The highest yield of all three elements could be achieved at 80 °C with a solid/liquid ratio of 1/20, where over 80 % of the As and Sn contained as well as nearly 40 % of the Sb contained was leached. Moreover, the temperature control was recognised as a crucial step within the process, and at the end proposals for further optimisation are presented, with special focus on the separate leaching of As and Sb.

KW - Anodenschlamm

KW - Charakterisierung

KW - Prozessentwicklung

KW - Laugung

KW - Zinn

KW - Arsen

KW - Antimon

KW - Edelmetalle

KW - anode slime

KW - characterization

KW - process development

KW - leaching

KW - tin

KW - arsenic

KW - antimony

KW - precious metals

M3 - Master's Thesis

ER -