Thyristor converters are more energy efficient than diode converters for the electrolysis of the non-ferrous metals-A case study in aluminium smelters at Hindalco, India

This paper presents and discusses AC-DC converters used for the Electrolysis of the non-ferrous metals and a case study of Aluminum Smelters at Hindalco to validate that thyristor converters are more energy efficient than diode converters. The most important factor in Aluminium production is the cost of energy used in the process of converting Aluminium oxide to Aluminium. This energy, which accounts for nearly 35% - 40% of the total cost of production of the metal, is primarily in the form of Direct Current (DC) power. DC Power is used in the process of electrolysis to convert Alumina (Aluminium Oxide) to Aluminium. With most of the production of electricity across the world is in the form of Alternating Current (AC) power, the process of conversion of this AC power to DC Power is critical. An efficient AC - DC converter becomes a critical component in the electrolytic reduction process of extracting non-ferrous metals in general and Aluminium in particular. The purpose of this research is to explore the reasons of mixed use of both the converter technologies, re-evaluate actual efficiency data on usage of both technologies and recommend the use of the more appropriate technology based on practical study.