International Journal of Engineering and Advanced Technology (IJEAT) ISSN: 2249 – 8958, Volume-8 Issue-6, August 2019 500 Published By: Blue Eyes Intelligence Engineering & Sciences Publication Retrieval Number E7913068519/2019©BEIESP DOI: 10.35940/ijeat.E7913.088619 Abstract: To accommodate the rising demands for artificial bone substitutes, the possibilities of extracting calcium oxide (CaO) as precursor of hydroxyapatite (HAP) from Scylla serrata (crab) shells via electric furnace and microwave kiln heating (calcination) were investigated. The crab shells were obtained from food wastes from local restaurants in Miri, Malaysia. They were treated by calcination with temperatures of 600°C, 800°C, and 1000°C for 3 and 4 hours in electric furnace. The shells were also calcined in microwave kiln at power levels of 60%, 80% and 100% for 1 hour. Characterization on the calcined shell samples were done using Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Diffractometer (XRD). Based on the FTIR and XRD spectra, it was found that calcium oxide was obtained through calcination at temperatures ≥ 800°C. The results also indicated that a higher calcination temperature and duration would yield CaO with larger crystallite size. Through calcination in microwave kiln, CaO was readily produced when calcination was done at 60% power. Keywords : Calcination, calcium oxide, crab shell, furnace, microwave. I. INTRODUCTION To accommodate the growing demands for bone grafting, alloplastic grafts have been widely researched to minimize the reliance on allograft and autograft methods as the bone grafts obtained through these means are very limited. Alloplastic grafts can be made from synthetic or natural hydroxyapatite (HAP) combined with other biopolymers such as collagen, chitosan and silk for bone regeneration enhancement [1]. HAP is a type of calcium phosphate which is very similar to human hard tissues in terms of the morphology and composition. Recently, it is gaining a lot of interest as a biomaterial due to its excellent properties. HAP may be classified into synthetic or natural depending on the methods of preparation. For instance, synthetic HAP can be produced through sol-gel [2], hydrolysis [3], and solid-state [4] methods. HAP can be synthesized through calcination [5], [6] and precipitation [7], [8] methods by using natural resources such as animal bones and shells. In Malaysia, there is an abundant supply of seafood with the wastes being ultimately disposed which in turn causes many environmental impacts. To address the environmental issues, this study aims at exploring the possibilities of extracting calcium oxide (CaO) which is a precursor for HAP from Scylla Serrata (crab) shells by solely using calcination Revised Manuscript Received on August 05, 2019. Vivien Yiik Mei Hii, Department of Mechanical Engineering, Curtin University, Miri 98009, Malaysia. Email: 7e4b3766@student.curtin.edu.my Fethma M Nor*, Department of Mechanical Engineering, Curtin University, Miri 98009, Malaysia. Email: fethma@curtin.edu.my Denni Kurniawan, Mechanical Engineering Programme Area, Universiti Teknologi Brunei, Gadong BE1410, Brunei Darussalam. Email: denni.kurniawan@utb.edu.bn method with the consideration of various parameters. These include the particle size of the samples, type of equipment for calcination of the samples, temperature, and duration of the calcination process. In addition to calcination using common electric furnace, this study also explores the usage of microwave kiln for the calcination, considering its low energy consumption. Microwave kiln has been used in previous calcination of sea shells [9]. II. METHODOLOGY A. Crab Shell Sample Preparation The shells of Scylla serrata were obtained from food wastes produced by local restaurants in Miri, Malaysia. Different parts of the crab shells were roughly washed with water and then crushed into smaller pieces. Next, the shells were immersed in 2.5 litres of acetone contained in a basin for 2 hours. After that, the shells were again rinsed with water to remove the remaining meat and soft tissues. Following this, overnight air drying was done on the crab shells to remove the remaining moisture. Then, crushing using pestle and mortar and further grinding using a dry blender were done on the crab shells to make them into smaller pieces and into powder, respectively. Lastly, the shell powder was sieved into two groups with particles of x ≤ 45 µm and 45 ≤ x ≤ 63 µm using sieve shaker (Endecotts, UK). B. Calcination Process Prior to the calcination process, the electric furnace (Carbolite, UK) was calibrated by using an infrared thermometer (RayTemp 28, ETI, UK) to measure the interior temperature of the furnace. Besides calibrating the furnace, the heating curves of the kiln in microwave (Sharp, Japan) at power levels of 60%, 80% and 100% (output power 900W) were also determined by using the infrared thermometer. Shell powder, of 4 – 5 grams, was weighed using a weighing scale and placed into the porcelain crucible using a spatula. For conventional heating, the shell powder was calcined using furnace with an average heating rate of 45°C/min (for the first ten minutes) with settings at 600°C, 800°C, and 1000°C for 3 and 4 hours. As for microwave heating, the shell powder was placed inside the microwave kiln and was subsequently heated at power levels of 60%, 80% and 100% for 1 hour. After that, the shell powder samples were taken out from the equipment to cool to ambient temperature. C. Sample Characterization The composition of phases and the size of crystallites within the shell samples were determined using X-ray Diffractometer (XRD) (XRD-7000, Shimadzu, Japan) with copper K-Alpha radiation. The XRD spectra were taken at 40 kV and 30 mA over a range of 2θ Scylla Serrata Shells Calcination using Electric Furnace and Microwave Kiln Vivien Yiik Mei Hii, Fethma M Nor, Denni Kurniawan