Synthesis and optimization of blended fireclay-chromium-silicon carbide for crucibles

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Onovo, H.O.
Sulyman, A.L.
Nnaji, R.N.
Orafunam, J.A.
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Unilag Annual Research Conference & Fair
Crucibles are produced through a proper blend of naturally occurring substances. This study characterized Ikorodu clay (Lagos state), graphite, silicon carbide, and chromium for the production of crucible pot, through varied mixing proportions of the constituent elements, categorized into three: A is 50:10:10; B is 40:20:10 and C is 40:10:20,representing the proportion of fire-clay, chromium and silicon carbide respectively. The specimens were blended and sintered with hydraulic press and dried at room temperature, followed by firing in an electrical furnace at a temperature of 1000°C for 3hours.The specimens were then subjected to a physio-mechanical and refractoriness tests using standard procedures for compressive strength, hardness, bulk density, and porosity. It was discovered that porosity varies inversely with bulk density. It is evident from the results that the compressive strength, hardness and porosity decreases as fireclay content of the specimen is reduced from mixture design A to C; considering 1.2 to0.58 MPa, 289 to 261 Hardness Leed Device (HLD), and 32 to 21 % for compressive strength, hardness and porosity respectively. Design of experiment (DOE) was adopted for the optimization of various parameters used in the experimental process. The approach provides useful insights in mixture design technique applicable in diverse mixture designs especially in crucibles or composites making. The optimal mixing proportion of the major elements for production of crucible pot was found to be approximately44, 16 and 10 percent by weight for fireclay, chromium and silicon carbide respectively with an optimum desirability of about 0.6.
Staff publications
Research Subject Categories::TECHNOLOGY , Crucibles , Refractoriness , Graphite , Silicon carbide
Onovo, H.O., Sulyman, A.L., Nnaji, R.N. and Orafunam, J.A. (2019). Synthesis and optimization of blended fireclay-chromium-silicon carbide for crucibles.