Arthur Kaniki - Academia.edu (original) (raw)

Drafts by Arthur Kaniki

Grinding tests were conducted on an oxidized copper-cobalt ore using a pear-shaped ball mill. Twe... more Grinding tests were conducted on an oxidized copper-cobalt ore using a pear-shaped ball
mill. Twelve mono-sized ore fractions were prepared and wet ground batchwise. The mill was run for 0.5
to 30 min intervals. The shortest interval provided data more closely related to the breakage function (B)
because less secondary breakage was hypothesized. Some selection function (S) and B parameters were
determined. Remaining parameters were estimated using a population balance model simulator. To evaluate
the kinetics model, an unsized ore sample was also milled. Predicted and measured particle size distributions
(PSDs) agreed well, suggesting that S and B parameters can be used for continuous operation
mass balances.

Papers by Arthur Kaniki

Journal of Environmental Science and Public Health, 2021

Background: The environmental pollution contributes to human exposure to TE through direct skin c... more Background: The environmental pollution contributes to human exposure to TE through direct skin contact with soil, inhalation of wind-blown dust, direct deliberate or unintentional ingestion of soil and ingestion of foods grown on TE-contaminated soils and waters.

Journal of Environmental Science and Public Health, 2020

Background: Worldwide, modern life is characterized by excess of toxicTE due to pollution (domest... more Background: Worldwide, modern life is characterized by excess of toxicTE due to pollution (domestic and industrial waste) and reduced intake of essential TE, consequence of imbalanced diet. In the context of cases of environmental pollution by TE documented in the city for years, the purpose of this study was to determine blood concentrations of essential TE and correlation coefficients in postdelivery mothers and their newborns living ˂ of 3km and >3km from the mining processing plants in the city of Lubumbashi, Congo. Method: Two prospective cohorts were formed based on distance between the home of the pregnant women and mineral processing plants (˂ of 3km and >3km).

Applied Earth Science, 2018

Cobalt in the Congolese Copperbelt mines is commonly recovered from Co-oxi-hydroxides (i.e. heter... more Cobalt in the Congolese Copperbelt mines is commonly recovered from Co-oxi-hydroxides (i.e. heterogenite, asbolane) by acid-leaching under reducing conditions. However, most operations face a limit in the leaching yields of cobalt, which usually do not exceed 80%. The main aim of this work was to investigate the causes of the poor recovery, in order to reconcile the Co recovery with processing techniques. Several concentrate samples from different mine plants of Katanga Copperbelt (Kalukuluku, Mutanda, Mabaya, Kamwali and Fungurume) were selected and subjected to a full mineralogical characterisation by Optical Microscopy (OM), X-Ray Diffraction (XRD), automated mineralogy and Scanning Electron Microscopy by Energy Dispersive Spectroscopy (SEM-EDS) prior and after leaching tests. OM and XRD results were used as background information to build a mineral list for mineral identification during automated mineralogy analyses by Mineralogic Mining System (Zeiss ltd.). Automated mineralogy allowed obtaining mineral maps, modal mineralogy, chemical assays and Co deportment for each specimen prior and after leaching. Mineral maps of the leached samples were useful to observe the occurrences of poorly leached Co-bearing particles which were further investigated by SEM-EDS and X-mapping. The results showed that heterogenite (rarely associated with asbolane) is the main cobalt mineral in Katanga. Mineralogic Mining System was able to discriminate between pure heterogenite, and Si-Al-K-bearing heterogenite, asbolane/heterogenite, Heterogenite+Fe-oxi-hydroxide and Co-bearing mixed phases, which resulted more refractory to leaching. The comparison between modal mineralogy of pre-and post-leached samples indicates a decrease, but not a full leaching of these Co phases: chemical assays and Codeportment, in fact, still reveal the presence of low Co% within Co phases listed above (Table 1). SEM-EDS and Xmapping on single particles of some specimens corroborated the results obtained by Mineralogic.

The Katangese Copperbelt area (KCA) located south-eastern of D.R. Congo presents high concentrati... more The Katangese Copperbelt area (KCA) located south-eastern of D.R. Congo presents high concentration of metal trace elements (MTE) in several soils due to a rich natural geochemical background, and intense mining activities, causing serious health issues to humans and animals. However, the lack of data on specific baseline concentrations makes it difficult to properly assess and monitor the environmental quality of soils in the region. In this study, the baseline concentration of 11 potentially toxic MTE (i.e., Mn, Zn, Cu, Co, Cr, Pb, Cd, Ti, Ni, Al, and Fe) was assessed in topsoils of the KCA, and the possible influence of land uses (croplands, forest and mining areas) was examined. Result delineated clear variability of metal concentrations across land uses. The highest concentrations of Cu and Zn found in mining areas than croplands and forests demonstrated a prevalent influence of mining activities in altering the natural background of metals concentrations in the region. By cont...

Minerals Engineering, 2017

Sulphuric acid agitation and column leaching tests of an oxidised copper-cobalt-bearing ore (1.44... more Sulphuric acid agitation and column leaching tests of an oxidised copper-cobalt-bearing ore (1.44% Cu and 1.04% Co) were performed to investigate its amenability to copper and cobalt metals extraction under reducing conditions. Oxidised copper-cobalt-bearing ores from the Congolese Copperbelt contain a large proportion of cobalt in trivalent form, which is readily soluble in solutions of sulphuric acid, provided a reducing agent is also present. Sodium metabisulphite (Na 2 S 2 O 5) is one of the most commonly recommended reducing agents, but its addition during the leach phase could cause significant environmental problems and could affect copper recovery if present in large amounts. During leaching, sodium metabisulphite reacts with sulphuric acid and dissociates to form SO 2 which in fact reduces Co(III). However, SO 2 is only partially utilised, and much of it is entrained unreacted in the leach liquor. A large accumulation of SO 2 can become uncontrollable and therefore escape to the environment if not consumed by the ore. The paper presents and discusses the effect of recirculation of the leach liquor after pH readjustment to 1.5 on the minimisation of unreacted SO 2 entrained in the leach liquor, sulphuric acid consumption; and the overall improvement of copper and cobalt extraction yields. The most important information found is that recirculation of the leach liquor proved to be very useful in reducing the amount unreacted SO 2 and significantly increasing recovered metals yields with little acid consumption. Moreover, the injection of Na 2 S 2 O 5 solution at 75% of the column bed-height considerably reduced the potential risks of SO 2 emanation.

Bioresource Technology, 2008

Chitin has been extracted from six different local sources in Egypt. The obtained chitin was conv... more Chitin has been extracted from six different local sources in Egypt. The obtained chitin was converted into the more useful soluble chitosan by steeping into solutions of NaOH of various concentrations and for extended periods of time, then the alkali chitin was heated in an autoclave which dramatically reduced the time of deacetylation. Chitin from squid pens did not require steeping in sodium hydroxide solution and showed much higher reactivity towards deacetylation in the autoclave that even after 15 min of heating a degree of deacetylation of 90% was achieved. The obtained chitin and chitosan were characterized by spectral analysis, X-ray diffraction and thermo gravimetric analysis.

Interleukin-18 (IL-18) is a proinflammatory cytokine that promotes natural killer (NK) and T-cell... more Interleukin-18 (IL-18) is a proinflammatory cytokine that promotes natural killer (NK) and T-cell activation. Several poxviruses, including vaccinia virus (VV), encode a soluble IL-18-binding protein (IL-18bp). The role of the VV IL-18bp (gene C12L) in vivo was studied with wild-type (vC12L), deletion mutant (v⌬C12L), and revertant (vC12L-rev) viruses in a murine intranasal model of infection. The data show that v⌬C12L was markedly attenuated, characterized by a mild weight loss and reduced virus titers in lungs, brain, and spleen. Three days after infection, NK cytotoxic activity was augmented in the lung, spleen, and mediastinal lymph nodes (MLNs) of v⌬C12L-infected mice compared to controls. Seven days after infection, v⌬C12L-infected mice displayed heightened VV-specific cytotoxic T-lymphocyte (CTL) responses in the lungs, spleen, and MLNs. Gamma interferon (IFN-␥) levels were also dramatically elevated in lavage fluids and cells from lungs of mice infected with v⌬C12L. Finally, we demonstrate that IL-18 is produced in vitro and in vivo after VV infection. Taken together, these data demonstrate a role for the vIL-18bp in counteracting IL-18 in both the innate and the specific immune response to VV infection and indicate that the ability of IL-18 to promote vigorous T-cell responses (cytotoxic activity and IFN-␥ production) is a critical factor in the accelerated clearance of the v⌬C12L mutant.

Journal of Materials Research and Technology, Jul 1, 2018

Journal of Sustainable Metallurgy

Journal of Cleaner Production