Recycle of Wastewater from Lead-Zinc Sulfide Ore Flo-tation Process by Ozone/BAC Technology

Xingyu Liu, Bowei Chen, Wenjuan Li, Yongsheng Song, Jiankang Wen, Dianzuo Wang

General Research Institute for Nonferrous Metals, Beijing, China.
National Engineering Laboratory of Biohydrometallurgy, General Research Institute for Nonferrous Metals, Beijing, China.

DOI: 10.4236/jep.2013.41B002                

Abstract

Lead-zinc sulphide ore contains lead sulphide (galena), and zinc sulphide (sphalerite). In the first flotation stage, galena is rendered hydrophobic with an organic collector such as xanthate, while sphalerite is kept from floating by depressants, and in the second flotation stage, activator was used to activated zinc flotation. Since the organic regent used are different in the two flotation stage, wastewater from the second zinc flotation stage can’t be directly recycled to the first lead flotation stage. Wastewater from flotation process for concentrating lead-zinc sulphide ore often containing organic compounds such as diethyldithiocarbamate(DDTC), xanthate, terpenic oil(2# oil) and thionocarbamate esters (Z-200), are environmentally hazardous. Their removal from contaminated water and the reuse of the water is one of the main challenges facing lead-zinc sulphide ore processing plants. In this study, synthetic wastewater containing DDTC, xanthate, 2# oil and Z-200 at concentrations ranging from 21 to 42 mg/L was fed into an Ozone/Biological activated carbon (BAC) reactor. Analyses of the effluent indicated a chemical oxygen demand (COD) removal over 86.21% and Total organic carbon (TOC) removal over 90.00% were achieved under Hydraulic retention time (HRT) of 4h and O3 feeding concentration of 33.3mg/L. The effluent was further recycled to the lab scale lead concentrating process and no significant difference was found in compare with fresh water. Furthermore, lead-zinc sulphide mineral concentrating process was carried out at lab scale. The produced wastewater was treated by Ozone/BAC reactor at O3 feeding concentration of 16.7mg/L and HRT of 4h. The effluent analysis showed that TOC removal was 74.58%. This effluent was recycled to the lab scale lead-zinc sulphide mineral concentrating process and the recovery of lead was not affected. The results showed that by using Ozone/BAC technology, the lead-zinc sulphide mineral processing wastewater could be recycled.

Keywords

Lead-zinc sulphide ore, Ozone/BAC, flotation wastewater, recycle

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	Barbaro, M., 2000. Encyclopedia of Separation Science. Editor-in-Chief: Ian, D.W. (ed), pp. 3215-3218, Aca-demic Press, Oxford.
[2]	Wills, B.A. and Napier-Munn, T., 2005. Wills' Mineral Processing Technology (Seventh Edition), pp. 267-352, Butterworth-Heinemann, Oxford.
[3]	Kinal, J., Greet, C. and Goode, I., 2009. Effect of grinding media on zinc depression in a lead cleaner circuit. Minerals Engineering 22(9–10), 759-765.
[4]	Glaze, W.H., Kang, J.-W. and Chapin, D.H., 1987. The Chemistry of Water Treatment Processes Involving Ozone, Hydrogen Peroxide and Ul-traviolet Radiation. Ozone: Science & Engineering 9(4), 335-352.
[5]	No?the, T., Fahlenkamp, H. and Sonntag, C.v., 2009. Ozonation of Wastewater: Rate of Ozone Consumption and Hydroxyl Radical Yield. Environmen-tal Science & Technology 43(15), 5990-5995.
[6]	Pocostales, J.P., Sein, M.M., Knolle, W., von Sonntag, C. and Schmidt, T.C., 2010. Degradation of Ozone-Refractory Organic Phosphates in Wastewater by Ozone and Ozone/Hydrogen Peroxide (Peroxone): The Role of Ozone Consumption by Dissolved Organic Matter. Environmental Science & Technology 44(21), 8248-8253.
[7]	Huang, W.-J., Fang, G.-C. and Wang, C.-C., 2005. The determination and fate of disinfection by-products from ozonation of polluted raw water. Science of The Total Environment 345(1–3), 261-272.
[8]	Hammes, F., Salhi, E., K?ster, O., Kaiser, H.-P., Egli, T. and von Gunten, U., 2006. Mechanistic and kinetic evaluation of organic disinfection by-product and assimilable organic carbon (AOC) formation during the ozonation of drinking water. Water Research 40(12), 2275-2286.
[9]	Chiang, P.C., Chang, E.E. and Liang, C.H., 2002. NOM characteristics and treatabilities of ozonation processes. Chemosphere 46(6), 929-936.
[10]	Xu, B., Gao, N.-Y., Sun, X.-F., Xia, S.-J., Simonnot, M.-O., Causserand, C., Rui, M. and Wu, H.-H., 2007. Characteristics of organic material in Huangpu River and treatability with the O3-BAC process. Separation and Purification Technology 57(2), 348-355.
[11]	Stalter, D., Magdeburg, A. and Oehlmann, J., 2010. Comparative toxicity assessment of ozone and activated carbon treated sewage effluents using an in vivo test battery. Water Research 44(8), 2610-2620.
[12]	DWAF, 1992. Analytical Methods Manual,, Department of Water Affairs & Forestry, Pre-toria.