Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.491113
Title: The biomechanical basis for glenoid labral tears
Author: Smith, Christopher David
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2008
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Abstract:
Froth flotation is the most widely used and versatile method for separating and concentrating minerals. Recent industrial experimental work has shown a positive metallurgical response can be achieved from a bank of flotation cells bv distributil1!.! the same volume of gas differently. This studv developed a froth based model of a rougher flotation bank to determine. by simulation. an air profile that will produce a high !.!rade concentrate from the first cell of the bank and a hi!.!h cumulative recovery. FrothSim is a phvsics based model of the froth zone in a flotation cell. This simulator has previously been used to model the !.!radc and recovery of multiple minerals from a sinulc tank. However. FrothSil1l requires experimental measurements of the overflowing bubble sizc and the fraction of the inlet air which overflows the \Veir of the cell as unburst bubbles. the air recavcn'. to make predictions. In this work FrothSil1l was used. for the first time. to develop a base case model of a bank of roLH!her flotation cells based on industrial experimental data. A close a!.!reement was obtained betwcen the modelled results and the experimental results for both floatable and cntrained minerals. A rigorous and robust procedure for the development of sin!.!le cell and full bank models was produced. An empirical model to predict the superficial velocity of the gas lost throu!.!h the froth surface has been developed. This model can be used to predict the air recovery from a flotation cell at different air rates. In conjunction. overflowin!.! bubble sizes were inferred from expcrimental data usin!.! a theoretical model. These were found not to vary significantly with air rate. These two models were combined with the FrothSil1l base case model to predict flotation performance at different gas distribution profiles. A new profile was found to vield the desired performance. The improved perfomlance can be attributed to an increase in froth recovery at all points in the hank. An industrial sampling campai!.!n was carried out to verifv the predicted operatin!.! performance for three eas distribution profiles. The experimental !.!rade rccoven' curves. for both floatable and primarilY entrained minerals. showed the same trends as the predicted results. The new gas distribution profile eave a hi!.!h grade concentrate from cell 1 and the hi!.!hest cumulatiye recoven'. This froth modelling approach. in which empirical models are combined with a physics based froth model can therefore be used to successfully manage gas distribution to a bank of cells.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.491113  DOI: Not available
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