Adsorbing Colloid Flotation of Pb(II). Feasibility of Utilizing Streaming Current Detector

Abstract

A feasibility study was conducted to assess the application of a streaming current detector (SCD) in the flotation of dissolved heavy metals. The adsorbing colloid flotation of Pb(II) with iron oxide and sodium dodecylsulfate was injvestigated. Both zeta potential and streaming current (SC) readings of each colloidal system were measured. For colloids of goethite or of amorphous iron oxide, the results show SC changed with pH values and can be well correlated to the zeta potential. The removal of Pb(II) increased with increasing pH. Judging from the experimental results, it is proposed that when pH is at 3.0 or lower, Pb(II) is mainly removed by foam fractionation. When pH values are between 4.0 and 7.0, Pb(II) removal can be attributed to both foam fractionation and adsorbing colloid flotation. When pH values are higher than 7.0, Pb(II) is mainly removed by precipitate flotation in the form of Pb(OH)₂(s) or Pb-Fe coprecipitate. Advantages and limits of utilizing SCD in flotation processes are discussed. Preliminary results show it is feasible for SCD to be utilized in the flotation of Pb(II).