Study of hazardous metals in iron slag waste using laser induced breakdown spectroscopy

Abstract

Laser Induced Breakdown Spectroscopy (LIBS) was applied for quantitative elemental analysis of slag samples collected from a local steel plant using an Nd: YAG laser emitting radiation at 1064 nm wavelength. The concentration of different elements of environmental significance such as cadmium, calcium, sulfur, magnesium, chromium, manganese, titanium, barium, phosphorus and silicon were 44, 2193, 1724,78578, 217260, 22220, 5178, 568, 2805, 77871 were mg Kg^{− 1}, respectively. Optimal experimental conditions for analysis were investigated. The calibration curves were drawn for different elements. The concentrations determined with our Laser-Induced Breakdown Spectrometers were compared with the results obtained using Inductively Coupled Plasma (ICP) emission spectroscopy. Our study demonstrates that LIBS could be highly appropriate for rapid online analysis of iron slag waste. The relative accuracy of our LIBS system for various elements as compared with ICP method is in the range of 0.001 - 0.049 at 2.5% error confidence. Limits of detection (LOD) of our LIBS system were also estimated for the elements noted here. The hazardous effects of some of the trace elements present in iron slag exceeding permissible safe limits are also discussed.

Keywords:

• Iron slag
• waste of steel plant
• multi-elemental analysis
• laser induced breakdown spectroscopy (LIBS)
• hazardous waste
• waste management
• trace metals.

Acknowledgments

The support by the Physics Departments and King Fahd University of Petroleum and Minerals is gratefully acknowledged. One of the author (T.H.) is thankful to National University of Science and Technology and Government of Pakistan for finacial support for his Ph.D work. He is also thankful to KFUPM for its hospitality and permission to work at its research facilties. Dr. A.H. Bakry is also grateful to KFUPM for permission to work at its facilities and for the hospitality during his stay at KFUPM.

Notes

*The peak wavelengths were identified using reference [30] and NIST data base.