PRECIPITATE AND ADSORBING COLLOID FLOTATION OF DISSOLVED COPPER, LEADAND ZINC IONS

By combining the precipitate and adsorbing colloid flotation, a possib ility for simultaneous removal of metal ions from aqueous solution con taining copper, lead and zinc ions (25 ppm each) is investigated. Ferr ic chloride is used as coprecipitant. Potassium oleate is used as coll ector and for the improvement of precipitation, while extra coprecipit ation of the ions still remaining in solution is realized via potassiu m ethyl xanthogenate, The test is carried out in the pH range of 4.0 t o 10, Two cells are used for precipitate and adsorbing colloid flotati on, differing in the way the gas bubbles are generated, i.e. dispersed -air and electrolytic flotation. The adsorption on colloid particles c ontaining the precipitated metal ions is checked out by registration o f surface tension at the liquid/gas interfaces both in the starting an d purified solutions according to the method of Wilhelmy. The concentr ation of each heavy metal ion in the supernatant liquid is measured vi a ICP optical emission spectrometry. The amount of heavy metals coprec ipitated with ferric chloride is determined from the difference in the ir concentration before and after coprecipitation, The optimal conditi ons under which copper, lead and zinc can removed almost quantitativel y from aqueous solutions are found.