Simultaneous production of impurity-free water and magnetite from steel pickling liquors by microwave-hydrothermal processing

Pickling plants produce large amounts of toxic and hazardous wastes containing heavy metals, thus creating an important environmental problem associated with steel production. This communication reports the use of the microwave-hydrothermal technology to remove metals from pickling liquors and also to produce electroceramics, which results in the simultaneous generation of impurity-free water and value-added materials. The results showed that the microwave-hydrothermal processing was efficient to produce magnetically soft ferrites, as well as to eliminate the heavy metal contamination from the spent liquor.