Karaktärisering av jäsande fumingslagg
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
At New Boliden’s Fuming plant at the copper smelter Rönnskär, Zinc is extracted from the copper slag in the form of Zinc clinker. The slag is treated at reducing conditions in the fuming furnace with injection of an air and coal mixture into the slag. In recent years the fuming plant has been experiencing foaming of the slag during slag tapping to the settling furnace, sometimes leading to slopping. During this master thesis work the slag has been characterised to investigate the foaming. The slag has been sampled from different steps in the process and analysed chemically. Certain samples have been analysed with Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD) to determine the phases and mineralogy of the slag. The fusibility was determined through the use of a Thermo microscope and the viscosity and melting behavior was examined by simple comparative melting. In addition to the practical examination of the slag, a literature survey was made focusing on slag foaming. From the literature it was concluded that the most influential parameters affecting foaming are; viscosity, the presence of solid particles and emulsions and the presence of surface active components. The SEM and XRD-study found chromium containing magnetite spinells and matte droplets in the slag. It was also noted that the phases and structures of the slag changed with the CaO content in the slag. Observations with the thermo microscope and the melting tests showed a difference in melting point and viscosity between foaming and non foaming slag. Foremost this study has shown that the slag exhibits large fluctuations in foaming behavior even during small variations within the slag. This implies that there are factors and relations affecting foaming which have not yet been identified. Slopping slag is not a separate definable state, but rather a floating scale of slopping probability dependent on a large set of interacting factors.
Place, publisher, year, edition, pages
2013. , 46 p.
Teknik, Jäsande slagg, Zinkfuming, Rönnskär
IdentifiersURN: urn:nbn:se:ltu:diva-56138Local ID: cef396fc-4ee5-44c1-a47f-35be0ae8f75aOAI: oai:DiVA.org:ltu-56138DiVA: diva2:1029525
Subject / course
Student thesis, at least 30 credits
Chemical Engineering, master's level
Validerat; 20130228 (global_studentproject_submitter)2016-10-042016-10-04Bibliographically approved