title: Recovery and Purification of Titanium Dioxide and Aluminium Compounds from Corundum By-product of the TiPro Process

authors: Jennings, Philip Anthony Charles

subjects: Aluminium

abstract: The TiPro process developed at the University of Waikato utilises an aluminothermic reaction to create titanium rich intermetallic alloys or alloy powders by solid-liquid separation. The product is then reduced with calcium vapour or calcium hydride to lower the oxygen content. This process involves intimately mixing titanium oxide powder with stoichiometric quantities of aluminium powder and heating the mixture to initiate a thermite reaction that transfers oxygen from the titanium oxide to the aluminium to produce titanium aluminide alloy and aluminium oxide. The liquid alloy is drained off from the by-product, called corundum, before going on to further processing. The corundum is left behind and contains significant quantities of valuable titanium alloy and aluminium and titanium oxides which must be recovered to increase the efficiency and lower the cost of the process.
	This thesis describes and explains proof-of-concept wet chemistry methods of processing the corundum by-product to recover and separate the valuable metal oxides. Using acid-base equilibria, over 90% of the titanium was recovered from the corundum phase as impure titanium oxide. Aluminium was recovered as aluminium hydroxide and aluminium oxide, both of which can be processed into feedstock for fresh aluminium smelting and hence represent a potential revenue stream. The products were characterised using SEM-EDX and XRD to determine their composition and structure. The proposed treatment produces no waste other than environmentally benign neutral salt water.

text: Recovery and Purification of Titanium Dioxide and Aluminium Compounds from Corundum By-product of the TiPro Process The TiPro process developed at the University of Waikato utilises an aluminothermic reaction to create titanium rich intermetallic alloys or alloy powders by solid-liquid separation. The product is then reduced with calcium vapour or calcium hydride to lower the oxygen content. This process involves intimately mixing titanium oxide powder with stoichiometric quantities of aluminium powder and heating the mixture to initiate a thermite reaction that transfers oxygen from the titanium oxide to the aluminium to produce titanium aluminide alloy and aluminium oxide. The liquid alloy is drained off from the by-product, called corundum, before going on to further processing. The corundum is left behind and contains significant quantities of valuable titanium alloy and aluminium and titanium oxides which must be recovered to increase the efficiency and lower the cost of the process.
	This thesis describes and explains proof-of-concept wet chemistry methods of processing the corundum by-product to recover and separate the valuable metal oxides. Using acid-base equilibria, over 90% of the titanium was recovered from the corundum phase as impure titanium oxide. Aluminium was recovered as aluminium hydroxide and aluminium oxide, both of which can be processed into feedstock for fresh aluminium smelting and hence represent a potential revenue stream. The products were characterised using SEM-EDX and XRD to determine their composition and structure. The proposed treatment produces no waste other than environmentally benign neutral salt water.

year: 2013

title: Flow maldistribution in industrial air heaters and its effect on heat transfer

authors: Atkins, Martin John

abstract: Flow maldistribution in cross-flow heat exchangers used for industrial air heaters or recuperators is fairly common and can lead to a number of undesirable effects, one of which is deterioration in the thermal performance. The effect of gross flow maldistribution and the improvement in the thermal performance of flow correction guide vanes is investigated using a laboratory heat exchanger apparatus. The thermal performance deterioration from maldistribution was up to around 30 %. Modest improvements in the overall heat transfer coefficient and heat exchanger effectiveness when vanes were used was found for the range of air-side Reynolds numbers tested. Vanes were found to reduce the deterioration in thermal performance by up to 60 % compared to a perfectly uniform flow situation. Based on the ε-NTU correlations the thermal performance deterioration is predicted to decrease as the number of tube rows (i.e. NTU) increases. The effective heat transfer area and therefore thermal performance of industrial air heaters and recuperators can be improved by using flow correction devices, such as guide vanes.

text: Flow maldistribution in industrial air heaters and its effect on heat transfer Flow maldistribution in cross-flow heat exchangers used for industrial air heaters or recuperators is fairly common and can lead to a number of undesirable effects, one of which is deterioration in the thermal performance. The effect of gross flow maldistribution and the improvement in the thermal performance of flow correction guide vanes is investigated using a laboratory heat exchanger apparatus. The thermal performance deterioration from maldistribution was up to around 30 %. Modest improvements in the overall heat transfer coefficient and heat exchanger effectiveness when vanes were used was found for the range of air-side Reynolds numbers tested. Vanes were found to reduce the deterioration in thermal performance by up to 60 % compared to a perfectly uniform flow situation. Based on the ε-NTU correlations the thermal performance deterioration is predicted to decrease as the number of tube rows (i.e. NTU) increases. The effective heat transfer area and therefore thermal performance of industrial air heaters and recuperators can be improved by using flow correction devices, such as guide vanes.

year: 2014-08-31

title: Telling “Us” in the “Days Destined to You: Response Life-Telling: Indigenous Oral Autobiography and the Performance of Relation

authors: Mahuika, Nepia

subjects: Arts & Humanities

abstract: This “tau-utuutu” (responsive) protocol feels familiar to me.² My turn to speak, to respond, to share in a conversation with Warren Cariou’s stimulating essay on “Life-Telling,” Indigenous autobiography, and Dovie Thomason. It reminds me of how life-telling, orality, and history, interweave and work in my tribal universe. At home, we take turns speaking. We inherit our words, we respond, carve, and weave new narratives—make them ours. Where I come from, lives are frequently “told,” sung, cried, carved, and performed, through tribal conversations, a chorus of textured tones, sometimes in a grand debate within which our personal and collective pasts, presents, and futures converge and diverge.³ I am glad, then, to be invited, to add my voice to this present discussion. It feels natural . . . normal . . . Native.

text: Telling “Us” in the “Days Destined to You: Response Life-Telling: Indigenous Oral Autobiography and the Performance of Relation This “tau-utuutu” (responsive) protocol feels familiar to me.² My turn to speak, to respond, to share in a conversation with Warren Cariou’s stimulating essay on “Life-Telling,” Indigenous autobiography, and Dovie Thomason. It reminds me of how life-telling, orality, and history, interweave and work in my tribal universe. At home, we take turns speaking. We inherit our words, we respond, carve, and weave new narratives—make them ours. Where I come from, lives are frequently “told,” sung, cried, carved, and performed, through tribal conversations, a chorus of textured tones, sometimes in a grand debate within which our personal and collective pasts, presents, and futures converge and diverge.³ I am glad, then, to be invited, to add my voice to this present discussion. It feels natural . . . normal . . . Native.

year: 2016