Gas phase extraction of metals from oxides using the ligand acetylacetone

• Main Author: Mariba, Epiphania Rumbidzai Memoraine
• Format: Others
• Language: en
• Published: 2010
• Online Access: http://hdl.handle.net/10539/8748

Gas phase extraction using organic ligands has been gaining interest because it eliminates many of the problems encountered in conventional mineral processing methods. This process was successfully used to extract iron using the ligand acetylacetone from Fe2O3 in a fluidized bed reactor, with above 80% extraction being achieved after four hours for some experimental conditions. The extraction was shown to be dependent on temperature, ligand flow rate and the surface area available for reaction, with extraction increasing as each of the variables was increased. Chrome could not be extracted successfully, with only a maximum of 12% extraction being achieved after four hours. It was shown that the process could be used to successfully separate mixtures containing both iron and chrome oxides by extracting iron and leaving chrome in the solid phase. Classic shrinking core reaction models were tested on data obtained to evaluate their fit of experimental data with theoretical predictions. The chemical reaction limiting shrinking core model was suggested to be the one that predominantly described the experimental data. There is need however to develop a model which takes into account the influence of all the variables identified as affecting the extraction. There is also need to identify ligands which will react selectively with other metal oxides and not iron in order to the see if the other metals can also be successfully extracted. Further work should be done on this promising technology.