Aspects of chemical and mineralogical assessment of the Ukpor clay, Nnewi South Local Government Area, Anambra State, Nigeria

                                        Akudinobi, B. E. B.

Nnamdi Azikiwe University Awka, Department of Geological Sciences, P.M.B. 5025 Awka Anambra State, Nigeria.

Abstract
Ukpor clay deposit maintains a common depth of emplacement of 0-4m. The X-ray analysis on the sample indicates that kaolin is the major constituent, with relative purity (estimated with area method) up to 95%. Values of compression and plasticity indices and dry density are 0.36, 24% and 2241kgm^-3 respectively, indicating favourable quality for many industrial applications.  These parameters exhibit good uniformity in all the samples, indicating significant isotropy and homogeneity in quality status of the bulk clay.  The chemical analysis results show that ferro-ion (Fe²⁺ and Fe³⁺) are the dominant geochemical species, with average concentration and standard deviation for three samples as 38mgl^-1 and 12 respectively.  The concentration values (mg1^-1) of alkali, alkali earth, and other non-ferro-metals (including Na, K, Ca, Mg, Mn, Cu, Zn, Pb,) range from non-detectable to < 1. The clay (as part of the thick sedimentary sequence characterizing Anambra basin) may have been primarily deposited but significant post-depositional input from other processes such as metasomatic silicification, weathering and reactions involving gibbsite (from lateritic cover) and pre-existing clays may have contributed significantly to its present form.  The observed properties favour many aspects of industrial applications such as in pharmaceuticals, refractories, adhesives and porcelain wares.  Predominance of iron and the subsequent colouration could be of industrial use in the manufacture of coloured wares and tiles, and magnetic ceramics, though further pre-application specific investigations are recommended.