Exploration And Metallurgical Processing Of Indium †Free Samples

Question: Discuss about the Exploration And Metallurgical Processing Of Indium. Answer: Introduction In the year 1863, two German chemists named Hieronymous Theodor Richter and Ferdinand Reich. They named the substance as indium from the blue colour seen from the spectrum. It was found to possess the ability of stabilising the nonferrous metals (Shanks et al., 2017). This study is based on finding the chemical and the physical characteristics indium, the exploration and the metallurgical processing of indium, recovery after mining of indium through the various recovery recycling techniques. Physical and chemical characteristics of Indium Indium is silver white metal which is lustrous and soft and has a face centred tetragonal crystalline structure. Indium is ductile and malleable and is able to retain its properties even at low temperature as low as absolute zero. This property of indium makes it ideal for the vacuum and cryogenic applications. At ordinary temperatures, in the presence of air indium metal cannot be oxidised. Whereas at high temperature, indium burns to trioxide. Indium when heated reacts directly with metalloids (tellurium, selenium, antimony, arsenic) and also with phosphorus, sulphur and halogens (Gunn, 2014). Trivalent indiums chemistry can be described as having covalent bonding. Indium is used as glass coatings due to the reflective properties which is equal to silver and also has corrosion resistance. Indium has two major oxidation states which is +3 and +1. Indium that occurs naturally exist in two different forms or isotopes like 113In and 115In (Gunn, 2014). Exploration and metallurgical processing of Indium It has been found that around 95 percent of the global indium resources are sourced from the zinc refineries as a by-product. According to a report of USGS the indium reserves of China increased from 208 tonnes to eight thousand tonnes. Russia along with USA, Canada and Peru all together have 8 percent of the global indium reserves. Due to the increase in the photovoltaics and LCD production, the exploration of indium has increased. Processing of indium- Indium is extracted from the residues of smelting and concentrating zinc ores and also from the recycling of the gases and dusts that are produced during the smelting of zinc. About 5 percent of indium is extracted from the residues of tin treatment and copper residues. Roast-leach-electrowinning process of zinc smelting is one of the renowned process of recovering indium from the zinc ore smelting (appendix figure 1) (Alfantazi Moskalyk 2003). Recovery and recycling of indium after mining The recovery of indium is achieved exclusively as a by-product of zinc. Extractive metallurgy process is developed in order to recover the indium from the treatable residues. Especially, indium is recovered at the Kidd Creek plant through the 3 stages (appendix fig 2). In the first stage iron is removed, in the second stage Cottrell dust from the copper smelter is integrated with the silver lead residue. In the third stage, liquor containing indium moves through an extraction of solvent stage. Indium is also recovered from the LCD displays and the process involves several stages. The first step employs the extraction of the indium through the usage of 2M sulphuric acid at a temperature of around 80 degrees Celsius for 10 min. Indium is extracted by the leaching process that continues subsequently (Amato et al., 2016). Conclusion Indium is a very rare element in the earths crust and the process of extraction of indium is very cost intensive. The process employed for the extraction and recovery of the indium has a close adherence with the zinc extraction process. Due to the rarity of indium, it is extracted recovered and recycled from the LCDs. References Alfantazi, A. M., Moskalyk, R. R. (2003). Processing of indium: a review. Minerals Engineering, 16(8), 687-694. Amato, A., Rocchetti, L., Fonti, V., Ruello, M. L., Beolchini, F. (2016). Secondary indium production from end?of?life liquid crystal displays. physica status solidi (c), 13(10?12), 979-983. Gunn, G. (Ed.). (2014). Critical metals handbook. John Wiley Sons. Shanks III, W. P., Kimball, B. E., Tolcin, A. C., Guberman, D. E. (2017). Germanium and indium (No. 1802-I). US Geological Survey.