| Title |
Solidification Characteristics of Digested Sewage Sludge Cake with Blast Furnace Slag |
| Authors |
김응호(Eung Ho Kim),김성호(Seong Ho Kim),조진규(Jin Kyu Cho) |
| Abstract |
A possibility of digested sludge cake solidification using blast furnace slag as a solidifying agent is investigated where the quick lime is used as a solidifying aid. Several tests are performed to investigate the solidifying effects and the applicability of the solidified sludge cake to daily or intermediate landfill cover material. The unconfined uniaxial compressive strength, pH, leaching of heavy metals, submerged effect and curing effect are measured, and XRD, SEM and EDS analysis are also conducted. The mixing ratios of solidifying specimen mixed with the blast furnace slag and the quick lime are varied in the range between 30 and 50, 5 and 20 percent of the digested sludge cake by weight. The best compressive strength results when the mixing ratio is 40 : 20. Data values for leaching pH and the concentration of leaching heavy metals from specimen for items of Cu, Pb, Cd, and Cr^(6+) are much less than those given in the Korean toxic waste criteria. The differences between air tight(moist) and air dried curing method are significant, but 1-day submerged curing shows little effects on the weight and the strength of specimen. Also, the compressive strength of specimen by air dried curing is much greater than by air tight curing. XRD analysis shows that the main solidification products are CSH, CAH and Ca(OH)₂. The microstructure analysis by SEM shows that needlelike crystals appear as the solidification proceeds. Also, the EDS analysis on these crystals confirms that the main components are Ca, Si and AI. |