Application of superconducting HGMS technology on turbid wastewater treatment from converter

Turbid return water from converter is a kind of dust scrubbing wastewater with both high suspended solid concentration and high turbidity, which contains suspended particles such as iron oxide, calcium oxide, silicon oxide, and so on. Usually, it is treated with flocculating sedimentation method, but the addition of flocculant would result in the higher operating cost. In this study, the wastewater from converter was disposed by superconducting high gradient magnetic separation technology. The experimental results showed us that it very useful for both pollutants separation and reuse of wastewater from converter. With the X-ray diffraction analysis, scanning electron microscopy and particles size analysis, the results indicated that not only the ferromagnetic iron oxide, but also weak magnetic substance such as calcium oxide and silica, and nanometer particles could be magnetically coagulated and trapped. Therefore, the suspended solid concentration could be stably controlled as less than 10 mg/L, and the wastewater could be recycled completely at the magnetic field gradient of 3 T. The data reported in this study suggest that the superconducting high gradient magnetic separation technology has a great application prospect: it could be applied without changing the main conventional wastewater treatment process, and it has the advantages of low investment and operating cost, easy and simple handling, and saving water and energy as well.

► Turbid wastewater from converter was treated by superconducting HGMS technology.
► The influencing factors of pollutants separating effect were analyzed.
► Within dozens of seconds, the removal rate of SS could reach up to almost 100%.
► Magnetic, nonmagnetic and nano scale particles in wastewater were separated.
► The superconducting HGMS technology has a great prospect of industrial application.