IRUNGU PETER WACHIRA I13/3135/2008

Transcription

1 IRUNGU PETER WACHIRA I13/3135/2008

2 Statement of the problem Objectives Study area Geology Materials and methods Data results and analysis Extraction mining and processing Uses and applications Recommendations Conclusions

3 Feldspars make up nearly 60% of the earth s crust Pegmatite minerals in which these feldspars are found include many gem materials, such as beryl, tourmaline, and garnet. Extreme rarity, small size, and lack of bright coloration has prevented paying as much attention to feldspars as the group deserves.

4 1. To identify and classify different feldspar deposits in the Namanga area 2. To determine the economic and industrial application of the identified feldspars 3. Generate a map showing feldspar deposits in the study area.

5 Namanga is a town in the Rift valley in Kajiado County on the Kenya Tanzania border. Rainfall from Ol Doinyo Orok mountain is the main source of water but is however not adequate enough. Residents have opted to scoop holes and wells dug in sand rivers to sustain their water needs. Its habitat consists mostly of open plains thorn bush lands and acacia forests with yellow barks. Amboseli national reserve provides the main tourist attraction in the area. Population is largely dependent on the borehole distribution

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8 CRYSTALLINE LIMESTONES (MARBLES) MIGMATITES KYANITE SCHIST QUARTZITES HORNBLENDE GNEISSES PEGMATITES

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10 ATOMIC ABSORPTION SPECTROMETRY GIS SELECTIVE STAINING OF K-FELDSPAR AND PLAGIOCLASE ON ROCK SLABS AND THIN SECTIONS

11 The method of staining plagioclase feldspar consists of etching the specimen with hydrofluoric acid vapour dipping it in barium chloride solution Rinsing treating the surface with a solution of potassium rhodizonate. This method of staining plagioclase is combined with the cobalt nitrite staining of K-feldspar to stain K-feldspar yellow and plagioclase red.

12 The basic feldspar recipe is X(Al,Si) 4 O 8, where X stands for Na, K or Ca. According to harmonised definition, feldspar products are aluminosilicates with Si02 content > 58%, Alkali content (Na20+K20) > 2%, Alumina content (Al203) > 3% and loss on ignition < 3%. In Pegmatites alkali content (Na20+K20) >6% and alumina content Al203 14%.

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14 Potashfeldspar Namanga Quarry Nkirumu Feldspar sample Namanga Feldspar sample Namanga Pure calcite Namnga Potash feldspar Al 2 O 3 Fe 2 O 3 SiO 2 MgO CaO MnO K 2 O Na 2 O CaCO _ _ _ _ _ _ _ _ _ _ _

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16 Alkali feldspar (also called potassium/potash feldspar or K-feldspar) are the most abundant in this area as shown by the data above. The feldspar ore is in the form of pegmatite veins Although there is presence of some sodium oxide in these rocks, its percentage does not surpass that of potassium hence the rocks are mostly potash.

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19 Best for Ceramic & Sanitary Ware Manufacturing - Application in both Glaze (K 2 O > 11.5%) & Body (K 2 O >10.5%) - gives White Firing Colour. Feldspar does not have a strict melting point, since it melts gradually over a range of temperatures. This greatly facilitates the melting of quartz and clays and, through appropriate mixing, allows modulations of this important step of ceramic making. Feldspars are used as fluxing agents to form a glassy phase at low temperatures and as a source of alkalies and alumina in glazes. Glass Grades - better fluxing from K 2 O > 10% (total alkalies > 13%), Alumina > 17% for strength, Low Iron Fe 2 O 3 at < 0.5%.

20 It is also used in welding road industries and in production of good quality, white portland cement. High Potash K2O >11% for Flux coated Welding Electrodes and spark plugs. As a bonding agent in the manufacture of bonded abrasives like wheels and discs of garnet, corundum, emery etc. Feldspar is mainly used as bonding agent along with magnesium oxide, magnesium chloride and other synthetic glue in the manufacture of abrasives, wheels, discs and other shapes.

21 It is also used in Enamel Brick Manufacturing, Wall Plaster and Roofing Belt Filler in Paints. The high potassium content and high strength of K-feldspar make it the best mineral for potassium-argon dating.

22 Feldspars in the Sultan Hamud and Lunyolorob Hill areas have shown to have potential to produce industrial amounts it would therefore be advisable to further look into these feldspars. Also with the numerous uses of feldspars more companies should be encouraged to mine, mill and refine feldspars for sale locally and for export given the huge demand from developed countries like the U.S.A and China and the emerging markets in Brazil The Middle East and India. Improved methods of characterising both plagioclase and potash feldspars can be both economical, less expensive and take less time than the traditional methods used. It is therefore advisable to invest in appropriate technology that would aid better analyse rocks suspected to have feldspars in them. More studies should be done in the Mozambique belt especially to find more of these deposits

23 From data from the samples collected in the area and taken to the Department Of Mines The type of feldspar was recognised as alkali feldspar and its characterisation from chemical analysis found that it contained alkali content (Na 2 0+K 2 0) >6% and alumina content Al > 14% and Si0 2 content > 58%. This in addition to confirmation that it was pegmatite feldspar was used to show the kind of products that could be manufactured from it. These include Ceramic & Sanitary Ware Manufacturing, fluxing agents, manufacture of bonded abrasives. Geological and physiography maps were also digitised to show the various geological formations for example the pegmatite vein in which the vein was found, and the general landscapes in the area.

24 THANK YOU