Chemical and mineralogical characteristics of lateritic iron ore deposit at iyuku, etsako west local government area of Edo state, Nigeria

The lateritic iron ore deposit at Iyuku in Etsako West Local Government Area in Edo State, Nigeria was assayed chemically and mineralogically. The results of the chemical assay obtained are Fe2O3 (48.20 – 55.63%), Al2O3 (12.50 –18.00%), SiO2 (9.48 – 30.71%) CaO (0.36 – 0.41%), MgO (2.51 – 2.60%) moisture (1.21 – 1.77%) and L.O.I (4.08 – 8.35%). The mineralogical analysis indicates the predominant presence of goethite, haematite and halloysite, whereas, gibbsite and anatase were present as minor species.KEY WORDS: laterites, goethite, haematite, halloysite, gibbsite and anatase

Spectrometric determination of ammonium-nitrogen with quinol in aqueous medium

Quinol is proposed as a reagent for the spectrometric determination of ammonium-nitrogen (NH4+-N) in aqueous medium. Quinol forms a pink complex with ammonium salt in aqueous medium. Hydrogen peroxide is needed for colour accentuation. The quinol/ammonium charge transfer complex has absorption maximum (λmax) at 420nm with molar absorptivity (ε) of 1.067x103lmol-1cm-1. Beer's law is obeyed up to 6.0μg NH4+-N/ml.The correlation coefficient (r) is 0.9962. The optimum quinol concentration and optimum pH are found to be 0.6% (m/v) and 5.00, respectively. The calculated sensitivity is 0.07μg NH4+-N/ml. The extent of ionic interference has also been quantitatively evaluated. The most tolerated ion is NO3- (8.00x10-3moll-1 maximum) and the least tolerated ion is Fe3+ (1.25x10-6moll-1 maximum). Recovery of NH4+-N from spiked water sample shows results in the range of 98.49 to 99.69%. The proposed method has been applied to the determination of NH4+-N in potable water. Results are in good agreement with those obtained by Nessler's method. Key words: ammonium-nitrogen, aqueous solution, spectrometry, quinol. (Global Journal of Pure and Applied Sciences: 2003 9(4): 495-502