Open Access Original Research Article

Formation of CaV2O6, CaSiO3 and CaMnO3 Salts During Thermo Chemical Leaching for Extraction of Alumina from Red Mud by Lime Soda Ash Sinter Process

S. N. Meher, B. K. Padhi

Current Journal of Applied Science and Technology, Page 41-52
DOI: 10.9734/BJAST/2011/205

Impurities like V2O5, SiO2 and MnOpresent in sodium aluminate liquor during thermo chemical leaching has a detrimental effect on the efficiency of alumina extraction from red mud. The objective of this study was to obtain information on the immobilisation of above impurities from red mud followed by formation of CaV2O6, CaSiO3 and CaMnO3 salts. During thermo chemical leaching alumina is extracted by sintering using Na2COand Lime grit waste material of Alumina refinery plant. During extraction of alumina from Bauxite by Bayer’s process, cationic impurities like Si, V, Mn of Bauxite and anionic impurities of liquor like chloride, sulphate and carbonate form Sodalite or Cancrinite resulting in soda and alumina loss (Sod or Can, ideal formula Na(Al6Si6O24X2YH2O; X-=Cl-, OH-,1/2CO32-,1/2SO42-, Al(OH)4-). In order to minimise the loss, a novel economic method was studied using lime soda sinter process. During sintering Sodalite or Cancrinite content of red mud form CaV2O6, CaSiO3 and CaMnO3,salts which enhance the alumina extraction. These impurities form CaV2O6, CaSiO3 and CaMnOsalts,which confirm the decomposition of Sodalite or Cancrinite by X-Ray Diffractometer (XRD) & Scanning Electron Microscope (SEM) and discarded with leached red mud. The effect of Na2CO3 and CaO additive, sintering temperature, time and leaching of alumina extraction study was carried out. Studies show that it was possible to extract alumina from red mud with maximum alumina extraction by immobilisation of impurities and formation of CaV2O6, CaSiO3and CaMnOsalts.


Open Access Original Research Article

Evaluation of the Groundwater Potential in Pompo Village, Gidan Kwano, Minna Using Vertical Electrical Resistivity Sounding

A. N. Amadi, C. D. Nwawulu, C. I. Unuevho, N. O. Okoye, I. A. Okunlola, N. A. Egharevba, T. A. Ako, Y. B. Alkali

Current Journal of Applied Science and Technology, Page 53-66
DOI: 10.9734/BJAST/2011/192

A study of groundwater potential of Pompo Village in the neighborhood of Gidan Kwano campus of Federal University of Technology, Minna, was carried out using Vertical Electrical Resistivity Sounding. A total of 12 Vertical Electrical Soundings (VES) were carried out across the area using the Schlumberger electrode array configuration. The sounding data was processed and interpreted using ZODDY and WINRESIST interpretation software. The underlying geo-electric section comprising topsoil, weathered basement, fractured basement and fresh basement was established. The Vertical Electrical Sounding curves revealed that the area is generally characterized by five geo-electric layers. The top soil layer is a highly resistive layer with thickness ranging from 0.3m to 1.6m. The second geo-electric layer is a resistive dry layer with thickness ranging from 0.9m to 4.3m. The weathered basement layer thickness varies from 0.9m to 9.1m. The fractured basement ranges from 2.1m to 16.4m in thickness, while the depth to basement varies between 4.9m and 25.3m. Out of the 12 VES carried out, 5 VES stations have been chosen as the most viable locations for the development of groundwater resources. Two types of aquifers, which are the weathered basement and fractured basement aquifer, have been delineated in this study. These aquifer units may have significant groundwater potential.

Open Access Original Research Article

Heat Transfer and Friction Factor Correlations for Rectangular Solar Air Heater Duct Having 60° Inclined Continuous Discrete Rib Arrangement

Thakur Sanjay Kumar, Vijay Mittal, N. S. Thakur, Anoop Kumar

Current Journal of Applied Science and Technology, Page 67-93
DOI: 10.9734/BJAST/2011/265

The heat transfer coefficient between the absorber plate and air can be considerably increased by using artificial roughness on the underside of the absorber plate of the solar air heater. An experimental study has been carried out for enhancement of heat transfer coefficient of a solar air heater having roughened air duct provided with artificial roughness in the form 60° inclined discrete rib. Increment in friction factor by provided with such artificial roughness element has also been studied. The effect of system parameters such as relative roughness height (e/D), relative roughness pitch (P/e) and relative gap position (d/W) have been studied on Nusselt number (Nu) and friction factor (f) with relative gap width (g/e) 1 and Reynolds number (Re) varied from 4105 to 20526. Considerably enhancement in heat transfer coefficient has been achieved with such roughness element. Using experimental data correlations for Nusselt number and friction factor have also been developed for such solar air heaters, which gives a good agreement between predicted values and experimental values of Nusselt number and friction factor.


Open Access Original Research Article

Geochemical Partitioning of Heavy Metals in Roadside Surface Soils of Different Grain Size along Major Roads in Kano Metropolis, Nigeria

O. J. Okunola, A. Uzairu, C. E. Gimba, J. A. Kagbu

Current Journal of Applied Science and Technology, Page 94-115
DOI: 10.9734/BJAST/2011/184

This study evaluates the effect of grain size on levels of metal in roadside surface soils collected along high traffic roads in Kano Metropolis as a consequence of increase in automobile over the years. Composite surface soil samples were collected along ten different roads. Samples were analysed for soil physicochemical parameters, heavy metals (Cd, Cr, Ni, Pb, Cu and Zn) content. On an average a six sequential extraction of roadside surface soils showed that Cd, Cr, Ni, Pb, Cu and Zn are predominantly occur in the Fe-Mn oxide, residual, residual, carbonate bound, organic and residual fractions respectively. It was found that concentrations in the water soluble and exchangeable fractions were generally low for most of the studied metals. Considering the proportion of metals bound to the water soluble to the exchangeable and the carbonate bound fractions, the comparative mobility of metals showed the order; Ni > Cd > Pb > Cr > Cu > Zn. Highest mobility factor (MF) for all studied metals was obtained in 150µm samples with exception of Ni, Pb and Cu where highest percentage MF was obtained in 1400µm samples and 355µm for Zn. This could indicate other sources than fine particulate emission form vehicles responsible. With toxicity it appears that Cd, Cr, Ni, Pb and Cu pollution along the roadside is of concern.

Open Access Original Research Article

Assessment of Cd and Cr Bioavailability in Sediment of River Challawa, Nigeria

A. Babale, A. Uzairu, J. A. Kagbu, O. J. Okunola, H. Abba

Current Journal of Applied Science and Technology, Page 116-130
DOI: 10.9734/BJAST/2011/136

Sediment quality assessment are a scientific tools that synthesize information regarding the relationships between the sediment concentrations of heavy metals and any biological effects resulting from exposure to these heavy metals. A field study was conducted to determine the physico-chemical parameters and level of Cd and Cr bioavailability of the river sediment of Challawa. The study revealed that the physiochemical parameters of river Challawa such as pH and organic matter favours bioavailability of Cd and Cr. The distribution pattern of Cr chromium in different fractions was in the order; Residual > Carbonate bound > Fe-Mn oxide bound > Organic bound > Exchangeable in the study and control areas. Chromium was associated mainly (65 – 93.3%) with the residual fraction in all the samples and relatively small amount of chromium occur in the non-residual fractions. The Cd association with different sediment fraction followed the order: Residual bound > Exchangeable > Carbonate bound > Fe-Mn oxide bound > Organic bound. In the residual fractions, 26.68% was associated with exchangeable. Also, despite the high levels of Cr, the very low percentages of the metal in the non-residual fraction indicate their limited environmental mobility. Cd is associated more with exchangeable and carbonate fractions, an indication of potential bioavailability of the metals. The potential risk to river water contamination was highest downstream (Site C) for Cd based on the calculated contamination factor. Based on this study, Cd posed the highest risk to Challawa river water contamination.

Open Access Original Research Article

Suppressive, Curative and Prophylactic Potentials of Morinda lucida (Benth) against Erythrocytic Stage of Mice Infective Chloroquine Sensitive Plasmodium berghei NK-65

Ebiloma Godwin Unekwuojo, Omale James, Aminu Rhoda Olubunmi

Current Journal of Applied Science and Technology, Page 131-140
DOI: 10.9734/BJAST/2011/273

Malaria caused by plasmodium parasite is at the moment the highest killer disease in the tropics, killing mostly pregnant women and children under the age of five years. Efforts are on to developing more potent antimalarials from plants’ sources that will be cheaper, without adverse effects, readily available and will be able to replace existing antimalarials that are already facing resistance by plasmodium. Morinda lucida is a medicinal plant used in many part of Nigeria for the treatment of malaria and other diseases. This work was set out to investigate the in vivo antiplasmodial effect of M. lucida in mice. The oral median lethal dose (LD50) was calculated to be 6400 mg kg-1 body weight. The in vivo antiplasmodial activity of M. lucida against early infection, curative effect against established infection and prophylactic effect against residual infection were as well studied in chloroquine-sensitive Plasmodium berghei NK-65 –infected mice. The extract at all the doses (100, 200, 400, and 800 mg kg-1, p.o) administered, produced significant (p<0.05), dose-dependent activity against the parasite in the suppressive, curative and prophylactic studies. The result of this study showed that M. lucida aqueous leaf extract posses potent antimalarial effects and may therefore offer a potential drug lead for development of a safe, effective and affordable antimalarial.