A Study on Treatment of Wastewater Containing Copper Species by Using Powdered BOF Slag

• Main Authors: Min-Ling Lee, 李敏菱
• Other Authors: 柯明賢
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/es2m2z

碩士 === 國立臺北科技大學 === 資源工程研究所 === 99 === The purpose of this study was to investigate the effectiveness of using powdered BOF slag to remove the copper-ion contaminants in wastewater. The BOF power, obtained from the burnt ashes, was purified and analyzed to have particle sizes of >900 μm, 150-900 μm, <150 μm and different L/S ratio for treating time period of 5, 10, 30 and 60 min. The set of experiments were designed to demonstrate the purpose of waste water treatment by utilizing the inexpensive BOF slag powder. Powdered BOF slag is heterogeneous oxide materials and analyzed to have the compositions of Fe2O3 46.0-51.6% and CaO 35.3-45.0%. The BOF powder with different particle sizes on L/S ratio 1000 and 30 min were tested for removal of Cu(Ⅱ) and Cu-EDTA solution. The results indicated that the smaller size of the powdered BOF slag the better for the copper ion removal. When the <150 μm size slag was used under the conditions of 30 min and L/S ratio 1000, nearly 100% of the total Cu(Ⅱ) in water solution was removed. The tests of different L/S ratio (200, 500, 1000 and 2000) at the treatment time of 5, 10, 30 and 60 min showed that the increase in L/S ratio and time period were generally the better results. For other tests of that <150 μm powdered BOF slag in L/S ratio 2000, it was determined to be 100% and 90% of Cu(Ⅱ) and Cu-EDTA solution, respectively. There results will be useful for future scale-up runs for further studies on the powdered BOF slag removal of the waste water containing copper ions. The experiments also showed that the powdered BOF slag had the main constituent CaO and other alkaline metals. Further investigation regarding of the released calcium and copper removal for powdered BOF slag was performed. It was found that the calcium component is responsible for the removal of copper ions. In the Cu-EDTA solution, the TOC concentration decreases if the treatment time increases. Both of Freundlich and Langmuir Isotherm Equations were followed and found that the data could be successfully described by the Freundlich Isotherm Equations. The recovered BOF slag powder from the treatment with copper ions was examined by using X-ray Diffraction (XRD) and Scanning Electronic Microscopy (SEM). The XRD pattern remained the same but the surface smoothness had increased in the case of Cu-EDTA solution treatment. By comparison, the Cu(Ⅱ) solution did not affect the powder particle surface. Furthermore, the solution after treatment was analyzed for the metal concentration to detect the possibility of metal leaching from the BOF slag powder. According to the TCLP test, the leaching concentration of Pb (Ⅱ), Cr(Ⅱ), Cr(Ⅱ), Cu(Ⅱ), Ba(Ⅱ), As(Ⅱ), Se(Ⅱ) and Hg(Ⅱ) was minimum. Overall, the evaluation of using the BOF slag power has proven to be useful and low-cost material for removing Cu(Ⅱ) ions from waste water.