REMOVAL OF CADMIUM FROM DILUTE-SOLUTIONS BY HYDROXYAPATITE .2. FLOTATION STUDIES

Dissolved-air flotation has been investigated in the present paper as a suitable solid/liquid separation technique, applied downstream for h ydroxyapatite ultrafine particles which were used in a preliminary sta ge for the removal by sorption of toxic cadmium cations. The main para meters affecting this process were evaluated, including the necessary quantity of sorbent material in the dispersion, the proper pH values o f Cd solutions, the type and concentration of supplementary inorganic flocculant agents (ferric chloride and aluminum sulfate), and the pres ence of additional surfactant added. The results obtained were conside red to be promising. Under optimum conditions, over 95% of Cd-loaded h ydroxyapatite particles were separated in a very short retention time.