Clay – a natural earthTo a clay mineralogist:   is a layer silicate mineral (called phyllosilicate) or    other mineral w...
Clay - classification As  smectite, vermiculite, kaolinite, illite, chlorite, allophane, hematite, geothite, ferrihydrite...
Kaolinitic Clay Deposit in South-west Nigeria                                 An estimated reserve                       ...
Purpose   To improve the thermal and physical    properties of     kaolinitic clay (south-    western Nigeria deposits) f...
Approach   Wood particles (sawdust)   Clay samples were collected from Ibule, Ikeji-    Arakeji and Ikere-Ekiti deposits...
Approach –Physical properties   Physical properties such as:       - bulk density,       - porosity,       - shrinkage,  ...
Approach   Ikere-Ekiti / Ikeji-Arakeji clay in ratios 50:50, 60:40 and    70:30 by mass.   Each blend was soaked separat...
Results – Characterization    Ikere-Ekiti Clay was an Alumino-Silicate clay (fire-clays) which consists     essentially o...
Results and DiscussionThermal and physical properties of selected clays and clay blends  Properties          Ikeji-   Iker...
Results and Discussion
Results and Discussion                     500                     450                     400CCS x 10 (Kn/m 2 )          ...
Results and Discussion
Results and Discussion
Results and Discussion
ConclusionClay blends - low sintering temperature, spalling resistance and coldcrushing strength as compared to standard v...
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ICWES15 - Effects of Sawdust Addition on the Thermo-Physical Properties of Some South Western Nigerian Clay Blends. Presented by Dr Christianah Olakitan Ijagbemi, Mechanical Engineering Department Nigeria

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ICWES15 - Effects of Sawdust Addition on the Thermo-Physical Properties of Some South Western Nigerian Clay Blends. Presented by Dr Christianah Olakitan Ijagbemi, Mechanical Engineering Department Nigeria

  1. 1. Clay – a natural earthTo a clay mineralogist: is a layer silicate mineral (called phyllosilicate) or other mineral which imparts plasticity and hardens upon drying or firing (Guggenheim and Martin, 1995) could be referred to as a particle size in a soil or sediment of a diameter < 0.002 mm or 2 microns) composed of silica (SiO2), Alumina (Al2O3) and water (H2O) plus appreciable concentrations of oxides of iron, alkali and alkaline earth.
  2. 2. Clay - classification As smectite, vermiculite, kaolinite, illite, chlorite, allophane, hematite, geothite, ferrihydrite, and lepidocrocite. Ofinterest in this study is the kaolinites, which are classified based on their physical properties, mode of formation and resistance to high temperature. Further classifications in relation to high temperature resistance are as: refractories, high melting clays and low-melting clays.
  3. 3. Kaolinitic Clay Deposit in South-west Nigeria An estimated reserve of 3 billion tonnes of good kaolinitic clay has been identified in many locations in Nigeria (south-west) ready for massive development and exploitation.* * South-West Nigeria
  4. 4. Purpose To improve the thermal and physical properties of kaolinitic clay (south- western Nigeria deposits) for industrial application as insulators .
  5. 5. Approach Wood particles (sawdust) Clay samples were collected from Ibule, Ikeji- Arakeji and Ikere-Ekiti deposits in Ondo, Osun and Ekiti states respectively. Clay samples were crushed to 150 µm and proportions needed for different analyses were weighed. Classical chemical analysis (Wet Analysis Technique) was used to determine the chemical composition(Beeley,1990).
  6. 6. Approach –Physical properties Physical properties such as: - bulk density, - porosity, - shrinkage, - sintering temperature, - spalling resistance, - cold crushing and strength and - thermal conductivity were determined using standard methods of the American Foundrymen’s Society (AFS, 1993).
  7. 7. Approach Ikere-Ekiti / Ikeji-Arakeji clay in ratios 50:50, 60:40 and 70:30 by mass. Each blend was soaked separately in a basin for 3days. Mixing and wet sieving was performed to remove deleterious particles followed by sun drying, crushing, grinding to fine particles to obtain 50 µm. Sawdust was mixed with the clay blends in varying percentages of 5, 10, 20 and 30%. Cubical, cylindrical, spherical and rectangular shapes were obtained from the blends and then thermo- physical properties determined using AFS (1993) method.
  8. 8. Results – Characterization Ikere-Ekiti Clay was an Alumino-Silicate clay (fire-clays) which consists essentially of Al2O3 and SiO2 associated with impurity oxides such as Fe2O3, TiO2, MgO, Na2O and K2O of about 13%. The ratio of aluminium oxide to silicon oxide of Ikeji-Arakeji (19.67:48.24) confirms the clay deposit as a bentonite-montmorillonite. Chemical composition of selected samples Chemical composition in wt % Oxide Ikeji-Arakeji Ikere-Ekiti Fire- clay ((Omotoyinbo & Oluwole, 2008) Al2O3 19.67 30.82 23 -34 SiO2 48.24 47.14 48-60 Fe2O3 10.81 2.00 2-4 MgO 1.33 0.32 TiO2 1.51 0.50 CaO 0.55 0.25 Na2O 0.87 0.80 K2O 3.00 1.90 Ignition loss 9.74 7.98 7-11 Others 4.78 1.09 Total 100.00 100.00
  9. 9. Results and DiscussionThermal and physical properties of selected clays and clay blends Properties Ikeji- Ikere- Ikere- Ikere- Ikere- Fire clay Arakeji Ekiti Ekiti/Ikeji Ekiti/Ikeji Ekiti/Ikeji accepted -Arakeji -Arakeji -Arakeji standard 70/30 60/40 50/50 range (Omotoyinbo & Oluwole, 2008)Bulk density 1.56 1.51 1.518 1.522 1.528 1.5-2.1(g/cm 3)Volume fraction 0.28 0.56 0.37 0.46 0.43 0.25-0.4of open porosityShrinkage on 4 2 2.47 2.63 2.91 3-7firing (%)Thermal 0.64 0.14 0.342 0.392 0.529 0.1-0.5conductivity(W/mK)Sintering 1200 1400 1430 1350 1300 1500-1750temperature (oC)Spalling 10 15 10 11 11 30+resistance(cycles)Cold crushing 4870 3610 3880 4090 4510 5000+strength (kN/m2)
  10. 10. Results and Discussion
  11. 11. Results and Discussion 500 450 400CCS x 10 (Kn/m 2 ) 350 300 250 70/30 200 60/40 150 50/50 100 50 0 0.37 0.39 0.43 0.48 0.57 0.61 Volume fraction of open porosity Fig. 4 Effect of porosity on cold crushing strength of clay blends
  12. 12. Results and Discussion
  13. 13. Results and Discussion
  14. 14. Results and Discussion
  15. 15. ConclusionClay blends - low sintering temperature, spalling resistance and coldcrushing strength as compared to standard values of 1500 0C – 1700 0C;30+ cycles and 5000+ kN/m2 respectively.The effect of sawdust addition on Ikere Ekiti and Ikeji Arakeji clayblends of 50:50, 60:40 and 70:30 showed that important properties suchas, bulk density, porosity, shrinkage and thermal conductivity, improved,thus making the blends fit as fire clay.However, the addition of sawdust has no effect on sintering temperature,spalling resistance and cold crushing strength.A 10 % sawdust addition to 70:30 Ikere Ekiti / Ikeji Arakeji clay blend,makes the blend fit as a fire clay.

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