Preparation for Ultra High Pure Indium Metal for Optoelectronic Applications

Abstract

Ultra high pure Indium metal is extensively used in optoelectronic devices. Indium and its alloys become potential candidates in aerospace, defense and communication sectors. Purification of Indium has been done by Instrolec-200 Refiner followed by Directional Melting/ Freezing and Solidification Systems. Major targeted impurities are Metallic impurities Ag, Al, As, Bi, Ca, Cu, Fe, Ga, Ge, Mg, Pb, Sb, Si, Sn, and Zn. Purified Indium is characterized by analytical techniques Inductively Coupled Plasma- Optical Emission Spectrophotometry and Inductively Coupled Plasma- Mass Spectrometry. Keywords—Indium, Purification, Instrolec-200 Refiner, Metallic impurities I-INTRODUCTION: SPHALERITE ores, Lead and Tin circuits, Zinc Flue Dust and Waste Liquors from Indium Plating are main resources from which Indium metal is recovered. Indium is minor metal in the earth's crust but it has unique and versatile combination of properties, Low melting point (156.5987 o C) and high boiling point (2072 o C) (5) . At -269.63 o C Indium becomes superconductor which makes it very useful in Cryogenics applications (4) . Ultra high pure Indium is used in several applications. Purification of Indium is very foremost operation. In purification process, if the purity of starting material remains low then even by using perfect and appropriate method, Ultra high pure and device grade product is very difficult to achieve. Multi Pass vertical zone refining is employed for purification of 3N pure Indium which is followed by Directional Melting/ Freezing and Solidification System. Purification is done with respect to some targeted impurities like Ag, Al, As, Bi, Ca, Cu, Fe, GA, Ge, Mg, Pb, Sb, Si, Sn, Zn and the results are obtained.