Layered double hydroxides from slags: Closing the loop

Abstract

The generation of non-desired slags in the metal extraction processes is a difficult-to-manage issue that becomes more intricate with the constant growth of metal production worldwide. As the metal demand rises so does the slag generated and, because of this, even though some uses have been found for slags, the bottleneck seems abiding. A most interesting and lately found application for these slags is the extraction of the metals present within to synthesize added-value products. In this context, layered double hydroxides (LDH), anionic clays with notable structural features, have been explored as output. Moreover, the often use of these LDH for remediation processes generates a double positive outlet: the recovery of a waste and its use with environmental purposes. In this review a compilation of the novel research featuring LDH synthesized from slags has been generated. The first sections present the major points of supply of slags and the most significant environmental applications of LDH. The unconventional sources of Fe and Al are described below, these metals are the most used in the industry and thus can generate a greater volume of slags. Following are the main investigations that have used these metals to synthesize LDH and the applications, with environmental interest, in which they have been used. The work ends with a section on conclusions and future perspectives.