Abstract The efficiency of Cd2+ foam separation with sodium lauryl sulfate and sodium laurate from sodium sulfate and sodium nitrate solution was tested. Foam fractionation of Cd2+ with lauryl sulfate in the form of a hydrated ion pair 2C12H25SO4, Cd2+ is ineffective because of a low recovery and high hydration of the foam. But ion flotation of Cd2+ as a low-solubility salt (C12H25COO)2Cd is highly effective. The presence of electrolyte in the solution has a negative influence on Cd2+ foam fractionation with lauryl sulfate because of an increase of inert salt concentration which causes competition for the collector between colligend Cd2+ and the added Na+ ions, and because of simultaneous increase in the thickness of water sheaths around the gas bubbles. In the case of ion flotation with sodium laurate, the presence of electrolyte improves Cd2+ recovery and decreases the thickness of the water sheaths around the gas bubbles. The interpretation of the results is based on the exchange of the collector count...