Efficient heterogeneous precipitation and separation of iron in copper-containing solution using dolomite

Iron removal is an inevitable step when recycling copper from wastewater. A new process is proposed to enhance iron removal selectively from copper sulfate solution through its chemical precipitation on the surfaces of dolomite (CaMg(CO3)(2)), which is a widely available cheap carbonate mineral. A heterogeneous precipitating reaction of iron ions on the surface of dolomite at 50 degrees C allowed for an efficient iron removal of 98.41% with only copper loss of 3.18% under optimized conditions. Different from that of calcite and magnesite, the surface of dolomite provided suitable alkalinity that was perfect for the adherence of iron ions rather than copper ones to precipitate. The idea of using dolomite, compared with the traditional alkaline neutralization, by adding, for example, Ca hydroxide to precipitate the metal ions together, demonstrated several environmental advantages: possible separation among heavy metals to enable easy recycling of target element, efficient purification of wastewater, and easy operation of precipitate sludge with low water percentage (48.32%).