Characterization of feldspathic deposits at virundiko area, Gairo district in central East Tanzania: implication for industrial viability

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The University of Dodoma
The Virundiko area is within the Mozambique belt which is highly occupied by metamorphic rocks mainly ganertiferous migmatitic biotite gneiss, within the pegmatites where big crystals of feldspar, mica and quartz are found. The pegmatite extends to about 15 to 20 meters thick. Partly, garnet amphibolite lithologies forms elongated lenses concordant to the main foliation of the area. Currently, there is no any study established regarding the suitability of feldspathic deposits within the area for industrial viability. Geochemical, mineralogical, physical and optical properties analyses are the techniques that have been used in this study to identify the industrial viability of the feldspathic deposits at Virundiko area in three sites namely KST1, KST2 and KST3). The ratio of K2O/Na2O in feldspathic deposits in all three sites is greater than 1, suggested that the traditional method of ceramic production. However, for saving cost modern technologies should be considered with the condition of minor mineral beneficiation to decrease the ratios of K2O/Na2O to be less than 1, this applies also in glass industries. It is stipulated that the feldspar deposit at Virundiko fits best in porcelain and high-voltage electroporcelain. Minor removal of coloring oxides (TiO2 and FeO2) should be done for white vitrified bodies such as white porcelain and glass. There is very low amount of calcium within the samples hence the deposits do not fit for electronics and biochemical equipments. The mineralogical analysis indicates that the samples are predominantly K-feldspar with big crystals of feldspar which ranges from 5cm to 20cm with few mica and quartz grains associated with positive geochemical analysis results suggestive for gemstones. Moreover, the physical tests indicate that, the minerals are of moonstone variety showing translucently milky white which are smooth when cut with durable without any fractures and cleavage joints. The feldspar minerals are moderately hard, the optical character of the samples displays adularescence phenomena with double refractive which add value to the beauty of these minerals when cut as a gem. Therefore, the results support that samples from all three sites fit for gemstone in a cabochon cut.
Dissertation (MSc in mineral exploration)
feldspathic deposits, industrial viability, suitability of feldspathic deposits
Francis, V. (2023) Characterization of feldspathic deposits at virundiko area, Gairo district in central East Tanzania: implication for industrial viability (Master’s Dissertation). The University of Dodoma, Dodoma.