Automation of monitoring and flue gas purification from HF by red mud on Søderberg cell site

Automated monitoring of the technological process at the site of Søderberg cells should be organized in order to provide timely adjustment of process parameter variation. The problem is set of disposal of red mud - alumina production waste, which is annually accumulated and dumped in slurry storages. There is about 1.5 ton of this man-made material for every 1 ton of alumina produced. The use of a vision system that captures all possible changes in the state of the technological process seems the most promising. The second component is the use of red mud as a fluoride absorber, which replaces traditionally used expensive alumina in the "dry" gas cleaning system. When using a complex of surveillance cameras informing the automated process control system and ensuring its prompt respond (in the case of changes in the process state) the use of red mud as a HF absorber increases the average absorption capacity of fluorine by 15%. As an absorbing additive the pulp of red mud with the ratio of L:S=5:1 is fed into the scrubber system to the site of flue gas purification from harmful compounds. The high absorption capacity of red mud is due to the presence of various metal oxides in its composition. It is feasible to use a complex of technical vision to obtain information. It solves the following tasks: provides the automated process control system with complete data on the process; introduces the technological process without any changes in the schedule of routine maintenance but significantly decreases human factor influence; predicts the anode effect; estimates the state of burners and conditions of flue gas afterburning (presence of flame, burner clogging, flame colour, nature of flame); rapidly assesses pressurization. Red mud is recommended to apply as an absorbent material for fluorides. In general, this will provide a positive environmental and economic effect.

Søderberg cell, monitoring automation, technical vision, fluoride emissions, hydrogen fluoride, red mud