Appraisal of the Talc Bodies of Kagara Area, North western Nigeria and their Industrial Potentials

Abstract

The study area, Kagara and its environs, lie within the Kushaka Schist belt of the Basement Complex of Nigeria, Tegina Sheet 142. Talcose bodies in the area occur in relatively small sizes except in Kumanu / Indaki area where they are massive and occur as inselbergs. The talc bodies occur in quartz ridge and pelitic-semi pelitic rocks and make contact with amphibolites and the migmatite-gneiss. Detailed geological mapping and sampling of the talc bearing and surrounding rocks were carried out using basic geological tools. This is to determine talc bodies that have not been reported before. Lithologically, the area comprises migmatite-gneiss, quartzites, amphibolites, pelitic semi pelitic rocks, arkosic rocks, granites and undifferentiated rock bodies. Thirteen samples of talcose bodies and host rocks were evaluated for their physical, mineralogical and chemical properties by petrographic, XRD and XRF analyses and the results of eight representative samples are presented in this study. Mineralogically, the talc bodies contain varying proportions of talc, tremolite, chlorite, anthophyllite and minor amounts of phlogopites, sapionite and stevensite which are alteration minerals. Chemically, most of the samples have high silica and magnesia contents >75% and CaO≤0.01%; Na2O +K2O<0.4%; As <0.05ppm; Pb <0.3ppm; Al2O3 generally ≤ 2.5% in most cases; P2O5≤0.01% and MnO≤ 0.22%. Firing tests showed some properties of talc such as colour, shrinkage, permeability specific resistance, hardness, strength and pore structure. It was observed that the samples analysed are composed of a good percentage of talc and other minor minerals such as clay, chlorite, anthophyllite, tremolite, sapionite and phlogopite. Comparison of the petrographic, mineralogical, chemical and physical data with some industrial indices indicate that the different samples have industrial potentials for ceramics, paints, paper, textile, rubber, crayons and plastic making. With appropriate beneficiation like floatation and bleaching, the different talc samples can become valuable to the cosmetics, pharmaceuticals and food processing industries.