Structural equation modelling the leaching of oxidised copper-cobalt ore in HCl aqueous solution
- Authors: Kime, Méschac-Bill , Mulaba-Bafubiandi, Antoine
- Subjects: Leaching optimisation , Oxidised copper-cobalt ore , Structural Equation Modelling (SEM) , Multiple regression , Path analysis , Factor analysis , SPSS statistics
- Language: English
- Identifier: http://hdl.handle.net/10210/18571 , uj:16015 , Citation: Kime, M-B., Maluba-Bafubiandi, A. Structural equation modelling the leaching of oxidised copper-cobalt ore in HCl aqueous solution.
- Description: Abstract: Structural Equation Modelling (SEM) is now widely used to explore the joint performance of factors affecting a process and to quantify the effect of each factor in the presence of the others. In this research work, SEM analysis was conducted to develop Structural Equation Models that well predict the leaching behaviour of Cu, Co, Ni and Fe in HCl aqueous solution of an oxidised copper-cobalt ore. A comprehensive set of experimental batch leaching tests was executed to study the effect of operating variables (pH, time, temperature and stirring speed) on the relative leaching yields of Cu, Co, Ni and Fe during the leaching of an oxidised copper-cobalt ore sample in an HCl aqueous solution. The gangue acid consumption was also measured to aid in understanding the behaviour of the gangue. The experimental results obtained were statistically analysed and modelled using the SEM procedure. The Structural Equation Models obtained showed that Cu and Co leaching yields had a strong positive dependence on both the leaching time and leaching temperature, while Fe leaching yield had a moderate dependence on the leaching temperature, stirring speed and the covariate Z (Z = stirring_speed*pH). On the contrary, Ni leaching yield had a strong negative dependence on both the stirring speed and the covariate Z. The Structural Equation Models agreed fairly with the experimental results obtained upon leaching. This is a clear indication that the models can be used to predict the leaching yields given a set of leaching parameters.
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Determination and scale-up of the milling parameters of a high talc containing oxidised copper-cobalt ore using a pear-shaped ball mill
- Authors: Kime. Meschac-Bill , Kaniki, Arthur , Mulaba-Bafubiandi, Antoine-Floribert
- Subjects: Pear-shaped ball mill , Population balance modelling , Selection function , Breakage function , Oxidised copper-cobalt ore
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/18435 , uj:15998 , Citation: Kime. M-B., Kaniki, A., Mulaba-Bafubiandi, A-F. Determination and scale-up of the milling parameters of a high talc containing oxidised copper-cobalt ore using a pear-shaped ball mill.
- Description: Abstract: The study reports on the grinding test conducted on an oxidised copper-cobalt ore in order to determine the milling parameters using pear-shaped ball mill. Twelve mono sized fractions of an oxidised copper-cobalt ore sample were prepared and wet ground batch wise using a laboratory-scale ball mill at the University of Lubumbashi: -6700 + 4750, -4750 + 3350, -3350 + 2360, -2360 + 2000, -2000 + 1700, -1700 + 1400, -1400 + 1000, -1000 + 850, -850 + 500, -500 + 250, -250 + 125 and -125 + 75 microns. After the sample and the balls were loaded to the ball mill, it was run for seven different time intervals (½, 1, 2, 4, 8, 15 and 30 minutes). The short time (½ minute) provided data more closely related to the Breakage Function (B) since less secondary breakage was hypothesised. The data collected was used to determine some of the selection (S) and B Function parameters. The remaining parameters were estimated using a population balance model simulator that seeks the best combination of these parameters in order to minimize the residual error between the experimental and predicted product size distributions (PSDs). To evaluate the kinetics model developed, an un-sized oxidised copper-cobalt ore sample was also milled for ½, 1, 2, 4, 8, 15 and 30 minutes. The measured (PSDs) obtained fairly agreed with the predicted ones. This suggested that the S and B Functions parameters obtained can be used for continuous operation mass balances.
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