Solidification/Stabilization And Speciation Analysis Of Cr In Tannery Sludge

With the rapid development of leather industry, advance study of tannery sludge treatment and disposal technology is imminent and also become part of the development of leather industry. Heavy metals stabilized in the tannery sludge are an important part of the sludge disposal. In this paper, tannery sludge has been preprocessed by solidification/stabilization technology because it is an inexpensive, viable sludge treatment technology. Tannery sludge as experiments for the study and has been using P·I cement as a curing agent to solidify/stabilize pretreatment. Concentration of Cr (Ⅵ) in leaching solution and mechanical properties of solidified block as the indexes by single-factor test to research the physical properties of the solidified block, Cr (Ⅵ) concentration during the cumulative leaching and the speciation Analysis of Cr in Tannery Sludge after Cementation Treatment. To investigate the mechanism of curing Cr (VI) and pore diameter distribution in cement sludge and the changes of mineral composition after solidification/stabilization was analyzed by X-ray diffraction (XRD) and Mercury intrusion porosimetry(MIP). According to the single factor experiment, it shows that:(1) Considered to Tannery sludge curing effect and economy, cement-solidified containing8%cement, water-cement ratio at0.8are appropriately.(2) Leaching trend is distributed into three phases:Transition phase, a sharp increase phase and stationary phase. After leaching35days, Cr (VI) cumulative leaching concentration curve trend stable level, indicating that Cr (VI) leaching has been completed. Internal aperture in solidified was increased after leaching.(3) A part of Cr (VI) in tannery sludge formed CaCrO4after cementation via X-ray diffraction analyzed.(4) The concentration of Cr as species in H2O extractable and Acid extractable reduced after different dosage of cement-solidified. The concentration of Cr as species in the H2O extractable and acid extractable increased gradually with curing age via Speciation Analysis.