Magnetic separation of industrial waste waters as an environmental application of superconductivity

Open gradient magnetic separation enables continuous operation of the separator without the need of matrix-elements. Such a separator consisting of liquid helium cryostat and an interchangeable pair of NbTi and Nb3Sn coils were designed and constructed for testing the separation of various substances. As an environmental application, synthetic and genuine steel mill waste waters were purified with the separator. Synthetic waste water contained dissolved Cr while genuine steel mill waste water contained Cr, Fe, Ni and Mo both in particle and in ionic form. Chemical treatment was needed to make the dissolved metals susceptible for magnetic field; this was achieved with the help of an adsorbent and ferromagnetic magnetite. Separated sludge was collected by attached pipeline. Cleaned waste water was first pH-treated and then analyzed by AAS-spectroscopy. Results showed that open gradient separator is a promising alternative for matrix-type separators.