Mechanical and flow properties of residue from dry desulphurization of iron ore sinter plant off-gas
C. Lanzerstorfer - Mechanical and flow properties of residue from dry desulphurization of iron ore sinter plant off-gas - ENVIRONMENTAL ENGINEERING SCIENCE, Vol. 32, No. 11, 2015, pp. 970-976
In off-gas desulphurization in sinter plants, dry systems consisting of a sorption process for the separation of sulphur dioxide and a fabric filter for final de-dusting are normally used. As a rule hydrated lime is the base sorbent although sodium bicarbonate can be an alternative. Mechanical and flow properties of the residues produced are relevant for the design of handling and storage facilities for these materials. In this study the mechanical and flow properties of residues from three dry off-gas desulphurization systems were investigated. The particle size and the density of all three residues was very similar but all other parameters measured differed depending on the sorbent used. The bulk density of the residues from lime based desulphurization was higher and the flowability was better. This has to be taken into account when a change of the desulphurization reagent from Ca(OH)2 to NaHCO3 is considered. Generally, the flowability of the residues was poor at low consolidation stress and improved at higher stress while the effective angles of internal friction and the wall friction angles decreased. The results produced by three flowability indicators (angle of repose, Hausner ratio, Carr´s compressibility) over-estimated the flowability of the residues considerably compared to the shear test results. Therefore, shear tests are strongly recommended for a reliable characterization of the flowability of such residues.