Joanna Pałdyna

Fractionation study in bioleached metallurgy wastes using six-step sequential extraction

The stored metallurgy wastes contain residues from ore processing operations that are characterized by relatively high concentrations of heavy metals. The bioleaching process makes use of bacteria to recover elements from industrial wastes and to decrease potential risk of environmental contamination. Wastes were treated by solutions containing bacteria. In this work, the optimized six-stage sequential extraction procedure was applied for the fractionation of Ni, Cr, Fe, Mn, Cu and Zn in iron-nickel metallurgy wastes deposited in Southern Poland (Szklary). Fractionation and total concentrations of elements in wastes before and after various bioleaching treatments were studied. Analyses of the extracts were performed by ICP-MS and FAAS. To achieve the most effective bioleaching of Zn, Cr, Ni, Cu, Mn, Fe the usage of both autotrophic and heterotrophic bacteria in sequence, combined with flushing of the residue after bioleaching is required. 80-100% of total metal concentrations were mobilized after the proposed treatment. Wastes treated according to this procedure could be deposited without any risk of environmental contamination and additionally the metals could be recovered for industrial purposes.

Determination of traces of Pt and Rh in soil and quartz samples contaminated by automobile exhaust after an ion-exchange matrix separation.

Monitoring of PGEs content in the natural samples is a crucial point in the environment science since catalytic car converters have been introduced. In the presented paper application of a very sensitive voltammetric method for determination of traces of Pt and Rh in the environmental samples contaminated by automobile exhausts is discussed. Voltammetric measurements were carried out in the supporting electrolyte containing formaldehyde and semicarbazide. PGEs were separated from the digested solutions of soils or quartz samples, collected from monitoring plots-by applying an ion-exchange resin Cellex-T. Pt was very effectively separated from the matrix approaching nearly 100% recovery after its elution by hydrochloric acid. Moreover the conditions of soil and quartz samples digestion were discussed. To validate the obtained result an independent analytical method-ICP MS was applied and analysis of certified reference material road dust 723-was completed.