Use of low-grade iron ore for producing a nano-adsorbent and a complex fertilizer

Abstract

We developed a technology that prepares magnetite nanoparticles (MNPs) from a low-grade iron ore and consumes the by-product wastewater in removing phosphorus and nitrogen in water. The silica that inhibits the MNP formation and that is present in the iron ore leachate was removed by co-precipitation with Al(OH)₃. From the supernatant, ferric hydroxide was allowed to be precipitated, leaving Mg²⁺ behind. The precipitated hydroxide was used as a starting material in preparing the MNPs of 5–15 nm in size by co-precipitation. The wastewater containing a large amount of Mg²⁺ generated from the ferric hydroxide precipitation stage was used to crystallize and ions in the form of struvite. This process enables the reduction of the cost of Mg²⁺ in water treatment and the cost of iron ore wastewater treatment. The valuable elements contained in the iron ore can be exploited to produce MNPs and struvite powder as a nano-adsorbent and a composite fertilizer, respectively. Our results suggest that low-grade iron ore or tailings can be applied to alleviate water and soil contamination.

Keywords::

• iron oxide
• nanomaterial
• environmentally friendly
• adsorption
• precipitation
• water pollution

Acknowledgements

This research has been performed as part of the project titled ‘Technology development for the synthesis of nano-materials precursors from mineral resources’ supported by the Ministry of Science, ICT and Future Planning of Korea. The authors thank the Geoanalysis Department at Korea Institute of Geoscience and Mineral Resources and the Division of Materials Science Research at Korea Basic Science Institute for the characterizations of chemical compositions and magnetic properties, respectively.

Disclosure statement

The authors declare no competing financial interest.

Notes

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