Investigation of the Nodularisation Propensity of Calcined Cashew-Nut Shell-Ash in Cast-Iron Melt Graphite

Abstract

Production of ductile iron using ferrosilicon-magnesium master alloy in melt treatment is currently fraught with challenges bothering on cost and availability. In this study the suitability of cashew nut shells ash (CNSA) as a viable alternative to magnesium master alloys employed in the treatment of molten cast iron for enhanced mechanical properties was studied. The carbonized CNSA used varied from 2-10 wt. % to treat different heat batches; CA1-CA5 containing varied amount of CNSA, CaO and FeSi in the molten cast iron. The cast samples were subjected to both mechanical characterisation (tensile, hardness and impact) and microstructural analysis using Instron electromechanical machine, impact tester and scanning electron microscope (SEM) coupled with energy dispersive spectroscope (EDS). Results show that the 8 wt. % CNSA addition demonstrated the best mechanical properties comparable to ASTM A536 ferritic ductile cast iron. Specifically, the 8 wt. % CNSA cast samples exhibited 433 MPa tensile strength, 144HRC hardness and ductility of 14.7%. Contributions to improved mechanical properties may be attributed to the development of sufficient fractions of graphite nodules during melt treatment with CNSA. These outcomes are a boost both to the production of quality ductile irons and a cleaner environment.
 Keywords: Nodularisation, ductile-iron, cashew-nut, ferrosilicon-magnesium alloy, mechanical properties

Extraction and physicochemical characterization of cashew nut-shell liquid in metal forming

“…Given the above description of CNS, it is safe to assert that, there is a high potential industrial application of CNSL if properly processed. Furthermore, the huge abundance of cashew nut in many southern states in Nigeria (Kogi, Oyo, Osun, Anambra, Imo and Enugu) and Africa generally necessitates the need to develop processes to recycle the huge tonnages of waste likely to be generated from cashew processing (Mwangi et al, 2013;Kyei et al, 2019;Sekunowo et al, 2021). For example, as at 2019, Nigeria produced about 100,000 metric tons of cashew nuts representing 12% of the world 835,000 metric tons (Agada and Sule, 2020;Adesanya et al, 2021).…”