REMOVAL OF COPPER (II) FROM AQUEOUS SOLUTIONS BY FLOTATION USING POLYALUMINUM CHLORIDE SILICATE (PAX-XL60 S) AS COAGULANT AND CARBONATE ION AS ACTIVATOR

摘要

Flotation is a separation technology for removing toxic heavy metal ions from aqueous solutions. Here a simple and rapid flotation procedure is presented for the removal of copper(Ⅱ) from aqueous solutions. It is based on the use of polyaluminum chloride silicate (PAX-XL60 S) as coagulant and flocculent, carbonate ion as activator and oleic acid (HOL) as surfactant. Both ion and precipitate flotation are included depending on the solution pH. Ion and precipitate flotation in the aqueous HOL-PAX-XL60 S-Cu~(2+)-CO_3~(2-) system gave powerful preferential removal of Cu~(2+) (F ～100 %) over the HOL-PAX-XL60 S-Cu~(2+) system containing no CO_3~(2-) ion (F ～86 %). The role of CO_3~(2-) ion is also evident from decreasing the dose of PAX-XL60 S from 700 mg l~(-1) to 200 mg l~(-1). The other parameters, influencing the flotation process, namely: metal ion, surfactant and PAX-XL60 S concentrations, ionic strength, temperature and foreign ions were examined. Moreover, the procedure was successfully applied to recover Cu~(2+) ions from different volumes up to 1 l and from natural water samples.