Effect of Sintering Temperature on Dielectric Constant of Silica Prepared from Rice Husk Ash

EFFECT OF SINTERING TEMPERATURE ON DIELECTRIC CONSTANT OF SILICA PREPARED FROM RICE HUSK ASH

Qudratun*, Iriani.Y , Kusumandari , Khoirum.S Departement of Physics Sebelas Maret University Ir.Sutami 36A street, Surakarta, Indonesia

Abstract

Silicon dioxide (silica) is one key material in micro- and nano-electronic industries. Silica from rice husk ash was synthesized by sintering at 800°C and 900°C. X-Ray Fluorescence (XRF) technique was used to determine silica content of rice husk ash. The dielectric constant obtained through LCR meter testing. Silica content of rice husk ash at 800°C and 900°C are 90,38 (wt%) and 90,56 (wt%) respectively. Only 87,3 % porosity at 900°C but at 800°C increased to 93,5 %. Dielectric constant (K) values for samples sintered at 800°C and 900°C are 5,85 and 6,02 respectively. The value increased with increasing sintering temperature.

Key words: dielectric constant, rice husk ash, sintering

I. INTRODUCTION thermodynamic phenomenon to convert unstable Rice husk is major waste product of the rice packed powder having excess free energy to industry obtained during milling of rice. It is stable agglomerates. During sintering, the atom reported that approximately 20% of rice in the powder particles diffuse across the produced rice husk [1,2]. World rice production boundaries of the particles, fusing the particles is approximately 645 million tons. South and together and creating one solid piece. Sintering South East Asia account for over 90% of world’s phenomenon involves fusion of particles, volume rice production [3]. In certain countries, farmer reduction, and increase in grainsize as well as burned the rice husk. This procecess would cause decrease in porosity. Porosity is the amount of environmental pollution. However, this problem pore in sample. can be solved by recycling the waste to produce Sintering process on rice husk as at higher eco-material having high end value [1]. temperatures can removed the unburned carbon Rice husk ash has been used in various from the ashes and crystalline silica is found, but industries such as steel, ceramic and refractory, at lower temperature amorphous silica is found cement and contruction industries and Silica [4,8]. Silica is one key in micro- and nano- source [4]. Silica called Silicon dioxide (SiO2) is the major chemical composition of rice husk ash. electronic industries. Silica as dielectric Metal Silica is a chemical compound that is a dioxide of Oxide Semiconductor gate has dielectric constant silicon. The melting point of silica is 1600°C [5]. about 3, 9. At different temperature heating for There are many methods to get silica such as synthesis silica give different silica content and titrimetric, precipitation and heating. Heating impurity. Dielectric property of the material is processed in the material fabrication at high one of fundamental character. Dielectric constant temperature called sintering [6]. Okuyama [7] is one of dielectric properties. So it is very defined sintering as an irreversible important to investigate dielectric constant of the impure silica [9].

* Corresponding Author.Tel: +6285-728462978 In this study, silica content in rice husk ash E-mail: [email protected] sintered at temperature 800°C and 900°C were

2 Qudratun ret al. / Proceeding of The ASEAN Conference on Science and Technology 2014, ISBN. XX (20XX) XX-XX determined by XRF. Dielectric constant of silica temperature give effect for percentage of silica in rice husk ash was examined by LCR meter. from rice husk ash. The porosity detected by Archimedes’ principle Tabel 1. with water as the medium. XRF analysis of silica content at different temperature II. MATERIALS AND METHODS Temperature (°C) Percentage of Silica (%) Raw material (rice husk) was supplied from 800 90,38 karanganyar, Indonesia. Rice Husk was washed 900 90,56 by aquades in order to remove clay and rock impurities and subsequently drying naturally by B. XRD Analysis the sun. The dried rice husk then milled by dry mill to be powder. The powder filtered into 150 meshs. The powder was molding to be pellet. The pellet taken in crucible and placed in nabertherm furnace at 300°C to get black ash and heated again at 800°C and 900°C to get rice husk ash. Analysis of silica content from rice husk ash was determined by XRF (X-Ray Flourescence). Crystal and amorph phases of the sintered RHA pellet were identified by XRD analysis. X-Ray

Diffractometer (Bruker D8 Advance) λCu about 1,5406 Å. Porosity calculated by equation (1). The initial weight of pellet sample was measure by the digital electronic scale. Then the measured pellet sample was soaked in water in a beaker Figure 1. XRD pattern of silica produced from rice husk ash glass for 24 hours at room temperature. As the at different temperature The XRD spectra of silica produce of rice samples were immersed in water, bubbles were husk ash is shown in Figure 1. A broad peak observed as the pores in the samples were filled centered at 2Ө angle of 22° at intensity 3632 with water. After the lapsed time, the samples confirmed the amorphous silica at 800°C. were removed from the beaker glas and allowed Whereas a sharp peak centered at 2Ө angle of to dry by removing the excess water on the 22° at intensity 11398 confirmed the crystalline surfaces dry napkin prior to weighing as wet silica at 900°C. It is believed that higher sintering weight. temperature give effect to form crystalline silica.

C. Porosity (1) Tabel 2. Dielectric constant and Porosity of the silica at different Dielectric constant examined by LCR meter temperature (LCR-800 Series Gwinstek). Dielectric constant Temperature (°C) Dielectric Porosity (%) measurement performed the capacitance value. The Constant dielectric constant can determine by equation (1). K is 800 5,85 93,50 dielectric constant, C is capacitance , A is surface area 900 87,30 of sample, d is thickness of sample, dan ε0 is dielectric 6,02 permittivity (8,85x10-12 Farad.m-1). Table 2 shows the value of dielectric

(2) constant’s silica from rice husk ash at 800°C is 5,85 and at 900°C is 6,02. Increament of

sintering temperature increased the dielectric

constant. Porosity at 800°C is 93.50% and

decrease to 87,30 % at 900°C. As sintering III. RESULT AND DISCUSSION progresses the pores become smaller, it shows at table 2 the porosity decreasing by increases A. XRF Analysis sintering temperature. Reduction of the pores XRF analysis determined silica content of rice make sample become more compact. It is husk ash. Table 1 shows the percentage of silica observed that the increment of sintering at different temperature. Silica content of rice temperature increased the dielectric constant but husk ash that sintering at 900°C is 90,56% and decreased the porosity. 90,38% at 800°C. More silica content got at higher temperature. It is believed that First Authoret al. / Mechatronics, Electrical Power, and Vehicular TechnologyXX (20XX) XX-XX 3

IV. CONCLUSION Sciences IJBAS-IJENSs,Vol:09 No:09. The effect of sintering temperature on pp.22-26. dielectric constant was investigated. Increase in [5] Mbaakan.C, Onojah.A, Gbaakpen.M, and sintering temperature at 900°C form crystalline Tragema.D, “Variation of Some Physical silica, increasing percentage of silica content Properties of Rice husk Ash Refracory with become 90,56% and dielectric constant increase Temperature”, International Journal of to 6,02 and consequently the porosity decreases Science and Research (IJSR), vol.2 , pp. 32– from 93,50% to 87,30%. 26, Sep. 2013. [6] Njoku.R.E, and Kennedy.A.R, “Effect of Sintering Temperature on The Density and ACKNOWLEDGEMENT Porosity of Sodium Chloride Preforms for The authors gratefully acknowledge to The open Celled Aluminium Foam Ministry of Higher Education (DIKTI) Student Manufacturing”, Nigerian Journal of Creativity Program for Scientific grant 2013. Technology (NIJOTECH) Vol.32, 2013, pp REFERENCES 117-122. [1] Prasad & Pandey, “Rice Husk Ash as a [7] Okuyama.K, “Powder Technology : Renewable Source for the Production of Fundamentals of Particles, Particle Beds, Value Added Silica Gel and Its and Particle Generation”, CRC Press, pp. Application,”BCREC,pp. 1-25,Jan.2012. 213-218,2006. [2] Kalapathy.U, Proctor.A and Shultz.J, “A [8] Thuduaij.N, and Nuntiya.A, “Preparation of simple Method for Production Pure Silica Nanosilica Powder from Rice Husk Ash by from Rice Hull”, Bioresource Technology, Precipitation Method”, Chiang Mai Jornal pp. 257-262, 2000. Scince vol 3, pp. 206-211.Oct 2007. [3] Balakrishnan.S, “Rice Husk Ash as a Support Material for Iron and Ruthenium [9] Cheng.Y and Jiang.L, “Study on the Based Heterogeneous Catalyst”, Thesis , Oct. Dielectric Property of the impure Silicon 2006. Dioxide Based on FEM”, in Proceedings of [4] Haslinawati.M, Matori.K , Wahab.H, and the 9th International Conference on Sidek .H, “Effect of Temperature on Properties and Application of Dielectric Ceramic from Rice Husk Ash”, Material, 2009.pp. 374-377. international Journal of Basic & Applied

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