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  1. 1. Manukaji John U. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 2, March -April 2013, pp.001-005Categorisation Of Clay Deposits In The Federal Capital Territory Of Abuja Manukaji John U. Department Of Mechanical Engineering Federal Polytechnic, Bida Niger State NigeriaABSTRACT Clay deposits in the Federal Capital geologic origin i.e. they were formed as alterationTerritory of Abuja were investigated with a view products of alumino-silicate rocks in anto categorizing them in order to determine their environment in which water is present. Ijagbemisuitability as insulating refractory material. The (2002)samples were collected from three different Clay minerals are produced mainly fromlocations in the territory, namely Sheda, Abaji the weathering of feldspars and micas. They formand Karimu, and labeled A, B, and C. In order to part of a group of complex alumino-silicates ofproject a better representation of the territory, potassium, magnessium and iron, known as layer-the samples were mined from ten cites each. The lattice minerals.Abifarin(1999) They are verymined clay samples from the ten cites were mixed small in size and very flaky in shape, and so haveproperly and a representative specimen for test considerable surface area Thring (1962). Furtherfrom that location was produced using the cone more, these surfaces carry a negative electricaland quartering system as recommended by the charge, a phenomenon that has great significance inAmerican Society of Testing Materials (ASTM). the understanding of the engineering properties ofAtomic Absorption Spectrometer(AAS) was used clay soils. Agha(1998)to determine the chemical composition, while To gain an understanding of the propertiesother established processes were used to of clay minerals, it is necessary to examine thedetermine other insulating properties like essential features of their layer-lattice structure.particle size distribution, specific gravity, bulk These comprise of the tetrahedral unit, whichdensity, solid density, water absorption, apparent comprise of a central silicon ion with fourporosity, permeability to air, refractoriness, surrounding oxygen ions and the octahedral unitthermal shock resistance, modulus of rupture, comprising a central ion of either aluminium orlinear shrinkage and thermal conductivity. The magnessium, surrounded by six hydroxyl ions. Inchemical analysis showed that all the samples both, the metal (with positive valency) is on thehad high percentages of silica and alumina, inside and the negative non-metallic ions form thethereby classifying them as Alumino-silicates. outside.Akinbode(1996) The values for specific gravity, bulk The layer structure is formed when thedensity, solid density and apparent porosity oxygen ions covalently link between units. Thus, aaveraged 2.75, 2.04 g/cm3, 3.18 g/cm3 , and 13% silica layer is formed of linked tetrahedral, having arespectively and they were within the general formula of nSi4010 (0H) 2. The octahedralinternationally accepted range. The values for units also link together at their apices to form alinear shrinkage, permeability to air and thermal layer, which may be either a gibbsite layer (Al 4 (0H)shock averaged 8.57% 69.4, and 29+ respectively 6), in which only two thirds of the central positionsand these also were within the accepted limits. are occupied by Al3+ ions, giving a dioctahedralThe values for modulus of rupture and thermal structure or a brucite layer (Mg6(0H)6), in which allconductivity averaged 81 MN/m2 and 0.494 the central positions are occupied by Mg2+ ionsW/moK. The refractoriness of all the samples giving a triotahedral structure.Li Zaigeng etwere >1300oC and this showed that they could be al(2001)used as insulating materials. The spacing between the outer ions in the tetrahedral and octahedral layers is sufficientlyINTRODUCTION similar for them to link together via mutual oxygen Clay minerals are fine- particle-size or hydroxyl ions. Two stacking arrangements arehydrous alumino-silicates which develop plasticity possible, giving either a two-layer or a three-layerwhen mixed with water. They vary over quite wide structure.Mahmoud et al(2003)limits in chemical mineralogical and physical In a two-layer lattice, tetrahedral andcharacteristics. A common characteristics is their octahedral layers alternate, while a three-layerlayer structure. They are all composed of electrical arrangement consists of an octahedral layerneutral alumino-silicate layers which move readily sandwiched between two tetrahedral layers. Mineralover each other, giving rise to such physical particles are built up when the layers are linkedproperty as softness, soapy feel and easy cleavage. together to form stacks.Chesti (1986)Manukaji (2004) All clay minerals are of secondary 1|Page
  2. 2. Manukaji John U. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 2, March -April 2013, pp.001-005Depending on the stacking arrangements and type of of mixing properly, spreading into rectangularions providing linkage between layers, their shapes and cones and taking the alternate portionsmineralogical and chemical composition, continued until a sizable quantity sufficient for theparticularly the clay mineral constituents, six main tests to be carried out were produced.groups of clay minerals may be identified: The resultant specimen for each sight were kept inkaolinite, montmorillonite, illite, chlorite, attapulgite P.V.C. bags and labeled as follows.and vermiculite Thring (1962). The presence ofminor amounts of mineral or soluble salt impurities LOCATION SPECIMEN LABELin clays can restrict their use. The more common Abaji Amineral impurities are quartz, mica, carbonates, iron Sheda Boxides and sulfides, and feldspar. In addition, many Karimu Cclays contain some organic materials.Clews (1969)Clay is an abundant raw material. However, certain The specimen were physically inspected for colourhigh grade types of clay deposits are limited in appearance and the following results as showngeographic occurrence and extent. Examples are the below were observed.white kaolin clays found in abundance only inGeorgia and South Carolina; the high quality SPECIMEN COLOURbentonites found in Wyoming, South Dakota, A GrayishCalifornia, Texas, and Mississippi; and the B Whitish ashattapulgite clays found in Georgia and Florida. C Ashy brownTheraja et al (1999). Each specimen was milled down using aMETHODOLOGY ball or hammer mill. It was soaked in water for 48 The clay samples to be used for the hours after which, it was dried by spreading it on amanufacturing of the base plates were mined from tray and placing it in the sun to dry. It was milled toten different locations on a particular cite in order to powdery form using a ball or hammer mill afterhave a good representation of the cite. Three cites which 600g of the specimen were sieved usingwere used in order to further give a wider sample 700µm, 500µm, 300µm, 100µm, 50µm. The sievespread. were placed on a mechanical vibrator operated for 30 minutes after which the content of each sieve wasFEDERAL CAPITAL TERRITORY: weighed.Sheda, Abaji, Karimu The mined clay samples from the ten locations on a In determining the chemical constituents ofcite were mixed properly and a representative the specimens, The Atomic Absorptionspecimen for test from that cite was produced using Spectroscopy method was used. In this process, thethe cone and quartering system as recommended by instrument was calibrated while solutions of thethe American Society of Testing Materials specimens were prepared.(ASTM).IEE(1992) The process involves mixing The clay samples were also analysed forthe samples and spreading them uniformly and other properties like Specific gravity, Bulk andequally into a rectangle. The rectangle is divided Solid Density, linear Shrinkage, Percentage waterinto four equal parts and two alternate portions were absorption, apparent Porosity, Permeability to air,taken, mixed properly and formed into a cone. The Refractoriness, Thermal Shock Resistance, Moduluscone was also divided into four equal parts while the of Rupture and Thermal conductivity, usingalternate portions were further taken. This process standard test procedures in BS 1902 Part 1 A 2|Page
  3. 3. Manukaji John U. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 2, March -April 2013, pp.001-005 RESULTS. TABLE 1: SIEVE ANALYSIS CLAY SPECIMEN Sieve no in Mo M1 %R %P µm SPECIMEN A 700 600 22.10 3.68 96.32 500 600 150.01 25.00 75.00 300 600 210.02 35.00 65.00 100 600 129.03 21.51 78.49 50 600 66.08 11.01 88.99 SPECIMEN B 700 600 16.10 2.68 97.32 500 600 100.25 16.71 83.29 300 600 201.07 33.51 66.49 100 600 168.74 28.12 71.88 50 600 85.01 14.17 85.83 SPECIMEN C 700 600 30.18 5.03 94.97 500 600 96.68 16.11 83.89 300 600 282.39 47.07 52.93 100 600 96.38 16.06 83.94 50 600 66.71 11.12 88.88Mo = mass of each sample of clay usedM1 = mass of each sample of clay retained in the TABLE 5: LINEAR SHRINKAGEsieve Clay A B C%R = Percentage retained specimen%P = Percentage passed % 2.38 2.32 2.08 averageTABLE 2: CHEMICAL ANALYSIS dryingOxides in shrinkagespecimen % 8.22 8.36 9.12 A B C averageSiO2 40 43 40 firingAl2O3 41 37 41 shrinkage at 1200oCFe2O3 1.0 1.0 1.4TiO2 2.2 2.2 2.0 TABLE 6: PERCENTAGE WATERCaO 0.3 0.1 0.6 ASORPTIONMgO 0.2 0.4 0.1 Clay A B CK2O 1.7 2.1 2.3 SpecimenNa2O 0.6 0.2 0.6 % water 30.3 29.5 28.9L.O.I 13 14 12 absorption at 110oCTABLE 3: SPECIFIC GRAVITY % water 3.2 3.0 2.9Clay A B C absorptionspecimen at 1200oCSpecific 2.69 2.58 2.98Gravity TABLE 7: APPARENT POROSITY Clay specimen A B CTABLE 4: BULK DENSITY AND SOLID % apparent 22 23 24DENSITY porosity at 110oCClay A B CspecimenBulk density 1.99 2.01 2.11 12 13 14 % apparentg/cm3 porosity at 1200oCSolid 2.84 3.24 3.46densityg/cm3 3|Page
  4. 4. Manukaji John U. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 2, March -April 2013, pp.001-005TABLE 8: PERMEABILITY CHEMICAL ANALYSISClay A B C TABLE 2 presents the chemical analysisSpecimen of the clay samples. The results showed that mostPermeability 68.7 69.3 70.1 of the clays were siliceous in nature, having theREFRACTORINESS highest number of silica present. Also the presenceTest cones were prepared from each clay specimen, of Aluminum oxide of the order of between 25—dried and placed in a furnace along with pyrametric 45% makes them to fall under the class ofcones designed to deform at 1000 , 1300, and Alumino-Silicate refractories.Hassan et al (1993)1500oC respectively in accordance with the The high Potassium oxide of samples B and CAmerican society of testing materials shows that there is high Mica content and this(ASTM).IEE(1992) The temperatures were then according to Phelps (1958) is good for casting.raised at 10oC per min. and was determined by themeans of an optical pyrometer. The maximum SPECIFIC GRAVITYtemperature available in the furnace was 1300oC The specific gravity values of the samplesand the test cones did not show any sign of failure in table 3 fell between 2.5 – 3 and this fell withinor deformation, meaning that all the clay samples the ranges for Nigerian clays as reported byhave a > 1300oC refractoriness. Akinbode (1996), Oaikhinan (1988). It is pertinent to note that the values comparedTHERMAL SHOCK RESISTANCE favourably with international range of 2.0 and 2.9.Test cubes 50mm square were also produced from Sample B had the lowest value of 2.58 whileeach clay specimen and put in an electric furnace sample C had the highest value of 2.98.Obi(1995)that already attained a temperature of 900oC. Theywere soaked there for 20 minutes after which they BULK DENSITY AND SOLID DENSITYwere brought out and cooled in stream of air. The The bulk densities of the samples werecubes were tested by using hand to pull them apart. shown in table 4 and the values fell within theIf they do not fracture or crack, they were returned internationally accepted range of 1.7—2.1g/cm3 forto the furnace for the process to be repeated. This fire clays .Thring (1962)process must continue repeatedly until fracture or The solid density of the samples also fell within thecrack occurs. The results showed that non of the internationally accepted range of 2.3—cubes cracked under 29 cycles. 3.5g/cm3.Ryan (1978) The highest solid densityTABLE 9: MODULUS OF RUPTURE value was recorded by sample C while the least Clay A B C was by sample A specimen M.O.R 8123 5329 5687 LINEAR SHRINKAGE Table 5 showed the linear shrinkage of the at 110oC samples at 110oC and 1200oC. The linear shrinkage KN/m2 values obtained at 1200oC varied from 8.22 in M.O.R 98 80 83 sample A to 9.12 in sample C. Although this gives at an indication of the efficiency of firing, it fell 1200oC within the internationally accepted value of 7— MN/m2 10% value for Alumino-silicates, Kaolin and TABLE 10 : THERMAL CONDUCTIVITY fireclays.Zubeiru(1997) CLAY A B C SPECIMEN WATER ABSORPTION THERMAL 0.472 0.542 0.468 Table 6 analyzed the percentage water CONDUCT absorption at 110oC and 1200oC. From the table, W/moK sample A showed the highest percentage of water absorbed while samples C showed the least atRESULTS AND DISCUSSION 110oC. At 1200oC, sample A also showed theFIRING COLOUR CHANGE. highest value while sample C showed the least. The samples showed some darkened Hassan(1990)colour changes at temperatures of 1200oC fromtheir original colour to ashy black. This was APPARENT POROSITY.however attributed to the fact that the firewood Table 7 showed the apparent porosity ofsmoke had serious effect on the colour change. the samples at 110oC and 1200oC respectively.SIEVE ANALYSIS Sample A had the least value while samples C hadTables 1 showed the particle distribution of the the highest at 110oC. Meanwhile all the samplesclay samples. It was however observed that most of fell within the internationally accepted value ofthe particles were retained within the sieve mesh of 20% and 80% Thring (1962) for fired bricks. At300μm 1200oC, samples A had the least value of 12% 4|Page
  5. 5. Manukaji John U. / International Journal of Engineering Research and Applications (IJERA) ISSN: 2248-9622 www.ijera.com Vol. 3, Issue 2, March -April 2013, pp.001-005while samples C had the highest of 14%. This silicate. The physical properties also showed thatshows that as the temperature increases, the the clay samples could serve as good refractorypercentage apparent porosity decreases, indicating materials for local industries particularly thosemore closure of the pores. This can be increased for involved in the manufacturing of spare parts.insulation purposes by adding saw dust, corn orrice husks.Olusola(1998) REFERENCES 1. Agha O A (1998) Testing of localPERMEABILITY TO AIR refractory clay for producing furnace The permeability of the samples were lining bricks. M. Eng. Thesis: Mech. Eng.presented in table 8. It is important however to Dept. F.U.T. Minnastate that all the samples had their permeability to 2. Akinbode F O. (1996). An investigationair within the internationally accepted value of on the properties of termite hill as25—90, following the observations of Hassan refractory material for furnace lining:(1990). Sample C recorded the highest permeability Indian Foundry Journal. Pp 11-13to air while sample A recorded the least. High 3. Abifarin M. S. (1999) Investigation onpermeability is highly recommended for insulating local refractory materials for highrefractories. The permeability can also be improved temperature applications, PhD Thesisby incorporating saw dust and rice husks in the mech. eng. dept. Federal University Ofclay, while molding.Manukaji(2004) Technology, Minna 4. IEE (1992) Wiring regulation requirementREFRACTORINESS for electrical installation BS7671 , 15th For the fact that all the samples did not Edition , A Mclay and co. Ltd Cardiffshow any sign of failure at temperatures of 1200oC 5. Ijagbemi C.O.(2002) Development andand above, it means that their sintering level is very performance evaluation of a biomass clayhigh and will fall within the internationally lined cookstove. Meng thesis , Departmentaccepted range of 1580oC – 1750oC. This of mechanical Federal University ofeventually showed that the samples have high and Technology Akure, Nigeria.good refractoriness qualities and can withstand the 6. Li Zaigeng and Zhou Ningsheng (2001)high temperatures the clay will be subjected to in Technological advancement in theoperation.Abifarin(1999) preparation and application of monolithic refractories. China’s refractories VolumeTHERMAL SHOCK RESISTANCE 10 number 1 All the samples showed a thermal shock 7. Mahmoud S., Ayman H and Mousa Aresistance of 29+ cycle. The thermal shock (2003) Pretreatment effects on theresistance for all the samples are acceptable for catalytic activity of Jordanian bentonite .siliceous fire clays. This property is vital for Journal of the clay mineral societymaterials used in places where heating and cooling Volume 51 number 1operation is carried out repetitively.Agha(1998) 8. Manukaji J.U.(2004) An investigation into the use of local clays as a highMODULUS OF RUPTURE. temperature insulator for electric cookers. Table 9 presents the values of modulus of PhD Thesis mech. eng. dept. Federalrupture for all the samples. At 110oC sample B University Of Technology, Minnashowed the least value while sample A showed the 9. Oaikhinan E.P (1988) Rheologicalhighest value. At 1200oC, all the samples showed properties of certain Nigerian clay.an improvement in their modulus of rupture but Proceedings of the international ceramicsample B still recorded the least while sample A conference Australia.still recorded the highest value.Ijagbemi(2002) 10. Olusola E O (1998) Investigation of Zungeru clay as refractory material forTHERMAL CONDUCTIVITY high temperature applications M. Eng. Table 10 showed the values of the thermal Thesis, Dept. of mech. engrg. F. U. T.conductivity test for all the samples. The values Minnashowed that specimen C had the least thermal 11. Obi V S (1995) Experimental analysis ofconductivity value, while the highest value was clay for refractory purpose , B.Eng.specimen B. The values are within acceptable range Thesis, Dept. of mech. engrg. F. U. Tfor refractories. Ijagbemi(2002) Minna pp 34-48 12. Theraja B. L. and Theraja A. K , (1999) Electrical technology, S. Chand and co.CONCLUSION Ltd, New Delhi The investigation revealed that thesamples are predominantly of the Alumino- 5|Page