Two-Stage Pot Gas Treatment Technology Allowing the Production of Sodium Sulfate

The key task of any socially responsible entity is to protect the environment from harmful effects of plant operation. UC RUSAL has developed and implemented at RUSAL Krasnoyarsk a two-stage pot gas treatment technology allowing the production of sodium sulfate, ensuring maximum efficiency in entrapping pollutants (dust, fluorides, and sulfur dioxide) and eliminating the need to build new landfills. Therefore, the important environmental task facing the plant has been solved. This paper describes the key process and technical aspects of the above technology. The first step includes the process of adsorbing fluorides and dust from the gas. The second step includes the process of adsorbing sulfur dioxide and the additional removal of the remaining fluorides and dust; and the third step includes the removal of sulfur, in the form of sodium sulfate, from the closed wet scrubber (WS) liquor circulation loop to increase the efficiency of the second gas treating step and eliminate the need to build new landfills. The resulting sodium sulfate can be used as a commercial product in paper pulp production.