Absorção do dióxido de carbono por resíduo de bauxita em torres de absorção

Abstract

One of the most discussed environmental problems on the world scene today is global warming and its implications. Although the greenhouse effect is a natural phenomenon, the increase in emissions of gases such as CO2 from the combustion process may favor its aggravation. Following this line, there is interest in conducting research to minimize the release of this gas in the atmosphere. This work aims to study the process of absorption of carbon dioxide by aqueous phase of bauxite residue (soda and dissolved ions in solution) in spray tower and tower saddles random (both pilot scale), as well as check the pH change in this absorption process to both towers. Evaluate pH change and CO2 absorption capacity by considering the following variables: the type of absorption tower, using the supernatant as the absorbent means and the use of the suspension heated by resistances. The results showed that the suspension of bauxite residue absorbed significant amount of CO2, both the spray tower as the tower saddles. The average absorption rate was around 8.42% for the spray tower and 9.34% for the tower saddles. The ability carbonating the suspension of 27%-p was about 33.3 kg CO2 per tonne of waste and there was a substantial reduction of the alkalinity of the residue by reaction with gaseous effluents with a mean decrease of 4.0 and 3.5 pH units for the tower saddles and sprinkler respectively.