Evaluation of solubility in simulated lung fluid of metals present in the slag from a metallurgical industry to produce metallic zinc

Abstract

The objective of this study was to determine the solubility parameters (rapid and slow dissolution rates, rapid and slow dissolution fractions) for nickel, cadmium, zinc and manganese compounds present in a pile of slag accumulated under exposure to weathering. This slag was generated by a metallurgical industry that produced zinc and zinc alloys from hemimorphite (Zn₄(OH)₂Si₂O₇.H₂O) and willemite (Zn₂SiO₄) minerals. A static dissolution test in vitro was used to determine the solubility parameters and Gamble's solution was used as the simulated lung fluid (SLF), on a time basis ranging from 10 min to 1 year. The metal concentrations in the slag samples and in the SLF were determined using Particle Induced X-rays Emission (PIXE). There are significant differences in terms of solubility parameters among the metals. The results indicated that the zinc, nickel, cadmium and manganese compounds present in the slag were moderately soluble in the SLF. The rapid dissolution fractions of these metals are associated with their sulfates. In conclusion, this study confirms the harmful effects on the neighboring population of the airborne particles containing these metals that came from the slag.

Keywords:

• Solubility
• simulated lung fluid
• heavy metal
• slag
• hazardous waste

Acknowledgments

The authors would like to thank CNPq and PRONEX for the financial support. We are grateful to Stella Salim (Departamento de Física/PUC-Rio de Janeiro, Brazil) for samples irradiation. We acknowledge Prof. Dr. Jari N. Cardoso for a critical reading of this manuscript.