The ideal aluminium smelting cell should operate at a fixed temperature and superheat. However, spatial and temporal operating strategies cause changes in temperature, which usually result in variations in superheat as well. Contrasting, in the long term, for mature cells the aluminium fluoride consumption is fairly accurately reflected by the soda and calcium oxide contents of the primary alumina. Therefore the poor control of aluminium fluoride concentration reflects the poor understanding of the causes of variation in aluminium fluoride concentration and molten bath mass within the cell. The aims of this thesis were to i. Develop a better understanding of how the dynamics of the aluminium smelting process impact process conditions ??? hence bath chemistry ii. Subsequently develop and evaluate diagnostic models that may be used to minimise the variations in chemistry in individual operating cells The key control feature to minimise adverse effects is Superheat. The ideal aluminium smelting cell should operate at a fixed temperature and superheat. However, spatial and temporal operating strategies cause changes in temperature, which usually result in variations in superheat as well. In this thesis industrial aluminium reduction cells and their material handling and dry scrubbing operation were analysed in respect to their energy and material balance. A number of experiments were carried out to study the influence of process parameters and operations on the state and path function of a cell. Bath inventory measurements lead to a better understanding of the underlying process behaviour, and it was obvious that energy and mass balance cannot be controlled independently. With regard to the response of bath inventory, bath and liquidus temperature to pot operation, the following interesting phenomena were identified: - some cells are active or inactive with respect to their response to aluminium fluoride additions - positive and negative voltage steps cause non-proportional changes in liquidus and bath temperatures - the liquidus temperature, bath volume and composition can respond rapidly to changes due to alumina feeding Successful application of the results and understanding developed in this research resulted in an energy requirement reduction of 1 kWh/kg

Thesis--University of Missouri, School of Mines and Metallurgy, 1888. / The entire thesis text is included in file. Holograph [Handwritten in entirety by author]. Title from title screen of thesis/dissertation PDF file (viewed December 17, 2009)

No description available.

The ideal aluminium smelting cell should operate at a fixed temperature and superheat. However, spatial and temporal operating strategies cause changes in temperature, which usually result in variations in superheat as well. Contrasting, in the long term, for mature cells the aluminium fluoride consumption is fairly accurately reflected by the soda and calcium oxide contents of the primary alumina. Therefore the poor control of aluminium fluoride concentration reflects the poor understanding of the causes of variation in aluminium fluoride concentration and molten bath mass within the cell. The aims of this thesis were to i. Develop a better understanding of how the dynamics of the aluminium smelting process impact process conditions ??? hence bath chemistry ii. Subsequently develop and evaluate diagnostic models that may be used to minimise the variations in chemistry in individual operating cells The key control feature to minimise adverse effects is Superheat. The ideal aluminium smelting cell should operate at a fixed temperature and superheat. However, spatial and temporal operating strategies cause changes in temperature, which usually result in variations in superheat as well. In this thesis industrial aluminium reduction cells and their material handling and dry scrubbing operation were analysed in respect to their energy and material balance. A number of experiments were carried out to study the influence of process parameters and operations on the state and path function of a cell. Bath inventory measurements lead to a better understanding of the underlying process behaviour, and it was obvious that energy and mass balance cannot be controlled independently. With regard to the response of bath inventory, bath and liquidus temperature to pot operation, the following interesting phenomena were identified: - some cells are active or inactive with respect to their response to aluminium fluoride additions - positive and negative voltage steps cause non-proportional changes in liquidus and bath temperatures - the liquidus temperature, bath volume and composition can respond rapidly to changes due to alumina feeding Successful application of the results and understanding developed in this research resulted in an energy requirement reduction of 1 kWh/kg

Thesis--University of Missouri, School of Mines and Metallurgy, 1885. / J. R. D. Owen determined to be John R. D. Owen from "1874-1999 MSM-UMR Alumni Directory". The entire thesis text is included in file. Holograph [Handwritten and illustrated in entirety by author]. Title from title screen of thesis/dissertation PDF file (viewed October 30, 2008)

No description available.

Thesis--University of Missouri, School of Mines and Metallurgy, 1903. / Year degree was granted determined from "1874-1999 MSM-UMR Alumni Directory". The entire thesis text is included in file. Typescript. Illustrated by author. Title from title screen of thesis/dissertation PDF file (viewed November 13, 2008)

Thesis (Ph.D.) -- McMaster University, 2001. / Includes bibliographical references. Also available via World Wide Web.

The equilibrium distribution measurements of As, Sb and Bi between molten copper and white metal and molten copper and matte were conducted to evaluate the activity coefficients of these impurity elements in copper smelting matte. The experimental results were analyzed through comparison and reconciliation with data in the literature. The following equations, based on a liquid standard state, were obtained for ᵞAs, ᵞSb and ᵞBi in white metal coexisting with copper phase at 1,150-1,200°C. Ln ᵞAs = -2.49 + 0.186 NAs; Ln ᵞSb = -1.23 + 23.5 NSb; Ln ᵞBi = 3.01 + 14.0 NBi where Ni represents the mole fraction of the element Bi in white metal. Analysis of the data demonstrated that a major factor in removing As, Sb and Bi in matte during smelting involves careful control of the sulfur pressure, ie. matte's sulfur content, the optimum matte composition's being those that approach the Cu₂S-FeS pseudo binary.

No description available.