• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • No language data
  • Tagged with
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Zinc recovery from baghouse dust generated at Ferrochrome foundries

Strobos, Johannes Gerhardus 31 October 2005 (has links)
During the production of ferrochrome in electric arc furnaces, a dust is captured in baghouse filters as a means of air pollution control. This dust contains various metals such as chromium, zinc, iron, aluminium and magnesium. Due to the presence of hexavalent chromium in the dust, which is both toxic and carcinogenic, it requires disposal at a hazardous waste disposal site, entailing high cost. The possibility exists that these costs could be reduced if metals such as zinc can be recovered from the dust through, inter alia, leaching. Experiments were performed to determine suitable conditions for the leaching of zinc from such a baghouse dust. A two step leaching procedure was followed which prevented the formation of silica gel. The most favourable conditions for zinc extraction was with a sulphuric acid concentration of 336 g/l and an acid to dust ratio of 0,56. Under these conditions zinc was selectively leached with regard to iron and aluminium. The percentage recovery for zinc was 71,2%, aluminium 1,8% and iron 0,1%. It was concluded that the second step (dilution) of leaching did not have a significant influence on the percentage extraction of metals from the dust. Consideration of the chemical treatment cost of waste streams produced led to the conclusion that zinc recovery from baghouse dust is not an economically feasible project viewed in isolation. However, compared to disposal at a hazardous waste disposal site such as Holfontein, approximately R467 054,00 per annum (based on a seven day week and baghouse dust production of 3 600 kg/day) can be saved. / Dissertation (MEng (Environmental Engineering))--University of Pretoria, 2006. / Chemical Engineering / unrestricted

Page generated in 0.0746 seconds