Akademik Veri Yönetim Sistemi
PHYSICOCHEMICAL PROBLEMS OF MINERAL PROCESSING, cilt.49, sa.2, ss.575-586, 2013 (SCI-Expanded)
One of the main problems for the natural stone industry is treatment of huge amount of waste sludge resulting from the cutting and polishing of them to produce slabs or tiles. The effective treatment of this sludge is very important for reducing of the sludge volume and overall operating costs. Previous studies showed that settling rate and water clarity of the supernatant solution can be increased by flocculation process. In this study, detailed electrokinetic studies were performed on the travertine samples received as natural and slurry form. The natural form of the sample was supplied from a travertine quarry while the slurry was taken from the cutting and polishing process wastewater collector pool of the processing plant. The electrokinetic measurements were conducted to find out the effect of suspension pH and the solid content on the surface potential of solid particles show that zeta potential (zeta) of travertine is positive at pH 9.76 over the all solid contents studied in this work. However, zeta of the particles become negative at lower pH values for 1% solid weight content. In contrast, for travertine slurry (6.73% solid weight), different potential variations were determined. The particles were negatively charged between pH 6 and 8. The results highlighted the effect of dissolved specific ions in the waste slurry and sensitivity of zeta to the ionic strength of the solution. The zeta measurements for a raw travertine sample, performed with different amounts of NaCl additions into the solutions, confirmed the above findings. An addition of low amounts of NaCl decreases zeta of the solid surface. Finally, the zeta measurements in the presence of polymer concentration of 0.001% to 0.1 % (wt/vol) clearly indicated that the flocculant molecules are adsorbed extensively on the travertine particles, and increase the surface potential of the particles with increasing reagent concentration.