A quality control model for the development of high-confidence flotation test data

 

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dc.contributor.advisor O'Connor, C T en_ZA
dc.contributor.author Lotter, Norman Owen en_ZA
dc.date.accessioned 2016-03-28T14:38:05Z
dc.date.available 2016-03-28T14:38:05Z
dc.date.issued 1995 en_ZA
dc.identifier.citation Lotter, N. 1995. A quality control model for the development of high-confidence flotation test data. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/18298
dc.description.abstract This thesis addresses the problem of obtaining reliable laboratory scale flotation test data for the Merensky ore type found in the Bushveld complex of South Africa. The complex nature of the platinum-group element (PGE) deportment in this ore renders the normally-practiced procedures inappropriate for this particular testwork. A more robust and thorough procedure is necessary because of the diverse mineralogical forms in which the PGE are found. The evaluation of the mass and value balances has accordingly to take these factors into account. The major features of the evaluation of input and output errors across the laboratory scale flotation test are analysed. It is found that unless size-by-size variance of PGE in a conventionally crushed mill feed is taken into account the mill feed sample size is underestimated by some 176%. Further the preparation of a reference distribution of assayed head material is necessary to provide the 95% confidence limits of grade estimate. The need for repeating flotation tests and compositing the adjudicated products is discussed, concluding that quintuplicates are suitable to achieve a desirable level of confidence in the built-up head grade. The sample preparation of the flotation products has a critical role in minimising evaluation errors, as is the case with fire assaying of samples where minimum numbers of replicate determinations have been calculated. An outlier rejection model for adjudication of the replicate built-up head grades is proposed, and a complete flowsheet of the quality control model is developed from first principles. The effect of this model on the PGE total balance is analysed. It is concluded that workable controls are defined, since a metal balance with < 1% error has been achieved. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Chemical Engineering en_ZA
dc.title A quality control model for the development of high-confidence flotation test data en_ZA
dc.type Master Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Department of Chemical Engineering en_ZA
dc.type.qualificationlevel Masters
dc.type.qualificationname MSc (Chem Eng) en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Lotter, N. O. (1995). <i>A quality control model for the development of high-confidence flotation test data</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering. Retrieved from http://hdl.handle.net/11427/18298 en_ZA
dc.identifier.chicagocitation Lotter, Norman Owen. <i>"A quality control model for the development of high-confidence flotation test data."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 1995. http://hdl.handle.net/11427/18298 en_ZA
dc.identifier.vancouvercitation Lotter NO. A quality control model for the development of high-confidence flotation test data. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Department of Chemical Engineering, 1995 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/18298 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Lotter, Norman Owen AB - This thesis addresses the problem of obtaining reliable laboratory scale flotation test data for the Merensky ore type found in the Bushveld complex of South Africa. The complex nature of the platinum-group element (PGE) deportment in this ore renders the normally-practiced procedures inappropriate for this particular testwork. A more robust and thorough procedure is necessary because of the diverse mineralogical forms in which the PGE are found. The evaluation of the mass and value balances has accordingly to take these factors into account. The major features of the evaluation of input and output errors across the laboratory scale flotation test are analysed. It is found that unless size-by-size variance of PGE in a conventionally crushed mill feed is taken into account the mill feed sample size is underestimated by some 176%. Further the preparation of a reference distribution of assayed head material is necessary to provide the 95% confidence limits of grade estimate. The need for repeating flotation tests and compositing the adjudicated products is discussed, concluding that quintuplicates are suitable to achieve a desirable level of confidence in the built-up head grade. The sample preparation of the flotation products has a critical role in minimising evaluation errors, as is the case with fire assaying of samples where minimum numbers of replicate determinations have been calculated. An outlier rejection model for adjudication of the replicate built-up head grades is proposed, and a complete flowsheet of the quality control model is developed from first principles. The effect of this model on the PGE total balance is analysed. It is concluded that workable controls are defined, since a metal balance with < 1% error has been achieved. DA - 1995 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1995 T1 - A quality control model for the development of high-confidence flotation test data TI - A quality control model for the development of high-confidence flotation test data UR - http://hdl.handle.net/11427/18298 ER - en_ZA


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