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The effect of leaching time and ammonia concentration on the atmospheric leaching of copper

- Ntuli, Freeman, Muzenda, Edison, Ramatsa, Ishmael, Belaid, Mohamed, Kabuba, John

A critics study of neural networks applied to ion-exchange process

- Kabuba, John, Mulaba-Bafubiandi, Antoine, Battle, Kim

  • Authors: Kabuba, John , Mulaba-Bafubiandi, Antoine , Battle, Kim
  • Date: 2012
  • Subjects: Neural networks , Ion-exchange processes , Copper ions
  • Type: Article
  • Identifier: uj:6027 , ISBN 978-7-5647-1031-6 , http://hdl.handle.net/10210/10048
  • Description: This paper presents a critical study about the application of Neural Networks to ion-exchange process. Ion exchange is a complex non-linear process involving many factors influencing the ions uptake mechanisms from the pregnant solution. The following step includes the elution. Published data presents empirical isotherm equations with definite shortcomings resulting in unreliable predictions. Although Neural Network simulation technique encounters a number of disadvantages including its “black box”, and a limited ability to explicitly identify possible causal relationships, it has the advantage to implicitly handle complex nonlinear relationships between dependent and independent variables. In the present paper, the Neural Network model based on the back-propagation algorithm Levenberg-Marquardt was developed using a three layer approach with a tangent sigmoid transfer function (tansig) at hidden layer with 11 neurons and linear transfer function (purelin) at out layer. The above mentioned approach has been used to test the effectiveness in simulating ion exchange processes. The modeling results showed that there is an excellent agreement between the experimental data and the predicted values of copper ions removed from aqueous solutions.
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Thermodynamics of Cu (II) adsorption onto South African clinoptilolite from synthetic solution by ion exchange process.

- Kabuba, John, Ntuli, Freeman, Muzenda, Edison, Mollagee, Mansoor

The effect of leaching time and ammonia concentration on the atmospheric leaching of copper

- Ntuli, Freeman, Muzenda, Edison, Ramatsa, Ishmael, Belaid, Mohamed, Kabuba, John

  • Authors: Ntuli, Freeman , Muzenda, Edison , Ramatsa, Ishmael , Belaid, Mohamed , Kabuba, John
  • Date: 2011
  • Subjects: Copper recovery , Leaching , Ammonia concentrations
  • Type: Article
  • Identifier: uj:5319 , ISSN 2010-4618 , http://hdl.handle.net/10210/8195
  • Description: The effects of ammonia concentration and leaching time were investigated to determine the optimum leaching conditions. The experiments were conducted in a leaching cell submerged in a water bath, with ammonia concentrations of 1.5 M, 2.0 M, 2.5 M and 3.0 M and varying leaching time from 0 to 300 min. Ni-Cu matte containing 23% by mass Cu was used in this experimental study. Increase in the concentration of the lixiviant was found to increase recovery when leaching for 130 minutes, with a recovery of 32.86% Cu using 3 M solution of ammonia. An increase in the leaching time resulted in more copper being leached for all lixiviant concentrations. However, leaching with 2 M ammonia solution gave a higher yield of copper compared to higher concentrations. This anomaly could be a result of cementation; Cu is displaced by Ni as Ni is a more electronegative metal than Cu .It was found that at higher concentrations more nickel was extracted.
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Kinetics study of ammonia removal from synthetic waste water

- Muzenda, Edison, Kabuba, John, Ntuli, Freeman, Mollagee, Mansoor

  • Authors: Muzenda, Edison , Kabuba, John , Ntuli, Freeman , Mollagee, Mansoor
  • Date: 2011
  • Subjects: Ammonium exchange , Langmuir isotherm , Clinoptilolite , Synthetic waste water
  • Type: Article
  • Identifier: uj:4698 , http://hdl.handle.net/10210/10933
  • Description: The aim of this study was to investigate ammonium exchange capacity of natural and activated clinoptilolite from Kwazulu-Natal Province, South Africa. X-ray fluorescence (XRF) analysis showed that the clinoptilolite contained exchangeable ions of sodium, potassium, calcium and magnesium. This analysis also confirmed that the zeolite sample had a high silicon composition compared to aluminium. Batch equilibrium studies were performed in an orbital shaker and the data fitted the Langmuir isotherm very well. The ammonium exchange capacity was found to increase with pH and temperature. Clinoptilolite functionalization with hydrochloric acid increased its ammonia uptake ability.
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Examination of flotation reagents suitable for nickel concentrator plant

- Kabuba, John, Muzenda, Edison, Ntuli, Freeman

  • Authors: Kabuba, John , Muzenda, Edison , Ntuli, Freeman
  • Date: 2011
  • Subjects: Nickel concentrator plant , Flotation reagents - Evaluation , Frother , Magnetic separation
  • Type: Article
  • Identifier: uj:6249 , ISSN 2010-4618 , http://hdl.handle.net/10210/8193
  • Description: Examination of flotation reagents suitable for a nickel concentrator plant was investigated using nickel sulphide ore. A number of different new reagents were examined for the best suit for the nickel concentrator plant. It was found that more nickel was found on the magnetic particles, which were assumed to be mostly pyrrhotite. A dosage of 50 g/t was found to be a suitable dose for the collector Betacol 380 AC and gave the best results, however, it was found to be expensive. Betacol 380 AB was found to be suitable at a dose of 75% g/t. There was no flotation improvement when depressants were used in conjunction with Betacol 380 AC. An activator (copper sulphate) was found to improve the grade of copper, nickel and iron meaning it activated pentlandite. The ions improved the flotability of sulfides at the normal process pH after grinding in steel mill.
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Influence of residence time and fine grinding on PGMS recovery and grade using a float characteristic test rig

- Muzenda, Edison, Kabuba, John, Ntuli, Freeman, Mollagee, Mansoor

Modeling of Co-Cu elution from clinoptilolite using neural network

- Kabuba, John, Mulaba-Bafubiandi, Antoine

Optimization of process parameters for castor oil production

- Muzenda, Edison, Kabuba, John, Mdletye, Philiswa, Belaid, Mohamed

Cu (II) removal from synthetic waste water by ion exchange process

- Muzenda, Edison, Kabuba, John, Ntuli, Freeman, Mollagee, Mansoor, Mulaba-Bafubiandi, Antoine F.

  • Authors: Muzenda, Edison , Kabuba, John , Ntuli, Freeman , Mollagee, Mansoor , Mulaba-Bafubiandi, Antoine F.
  • Date: 2011
  • Subjects: Clinoptilolite , Ion exchange , Synthetic waste water , Waste water treatment , Heavy metals - Removal
  • Type: Article
  • Identifier: uj:4708 , ISSN 2078-0966 , http://hdl.handle.net/10210/10953
  • Description: The objective of this study was to investigate the potential of acid activated South Africa clinoptilolite as an adsorbent in the ion-exchange process for the removal of cations from aqueous solutions. The kinetic parameters affecting the adsorption of Cu (II) ions were studied. The adsorption of Cu (II) from synthetic waste water was found to be dependent on pH, temperature, contact time and initial adsorbate concentration. The pH was varied from 2.5 to 6 and the optimum pH for Cu (II) removal was found to be 4.0. The removal of Cu (II) ions increased with time and attained saturation in about 60-70 min. The equilibrium data showed that the adsorption was endothermic nature. Kinetics data showed that at higher temperatures, the rate of adsorption is higher for the clinoptilolite natural zeolite and that Langmuir equation successfully described the adsorption process.
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