Reduction of Emission from Aluminium Industries and Cleaner Technology

摘要

Aluminium metal is produced by electrolytic reduction of alumina in cells lined with carbon blocks. During the process of smelting different gaseous emissions like PFC (per fluorocarbon), HF, PAH (poly aromatic hydrocarbon), CO_2, SO_2, particulate matters etc. occur in to the atmosphere. The concentration of emission from a cell depends upon the type of cell, bath chemistry, scrubbing system and gas cleaning equipment used. These emissions cause severe environmental damages such as global warming and disease like fluorosis, cancer, asthma, emphysema, bronchitis etc. Through the development of newer technologies like, introduction of prebake technology, use of non-consumable (inert) anode, use of computer controlled and point feeding of alumina to the cell to control the frequency and duration of anode effects, use of low carbon pitch to replace tar, use of pollution monitoring and control equipment etc., there is a significant reduction in the emission levels. This paper deals with the factors influencing the generation of these emissions and its reduction through the development of various cleaner technologies. Use of pollution control equipment and other remedial measures to minimise the environmental pollution are also discussed.