Magnetic properties of bauxites and pre-fused hydrothermal product (zeolite)

Abstract

Bauxites are deposits rich in aluminium and iron oxides/hydroxides, formed by the weathering of aluminosilicates rocks under warm and humid conditions. Due to their mineralogical composition, bauxites represent the primary source for aluminum and, subordinately, iron production. However, these sediments rich in Si and Al can be also used as raw material for the synthesis of zeolite with magnetic properties thanks to the high availability of Fe. In this work, three bauxite samples collected from Upper Cretaceous deposits of southern Italy were characterized for their magnetic parameters and used for the synthesis of zeolite with LTA topology (zeolite A). The results indicate differences in antiferromagnetic behaviour among the three raw materials. All the synthetic products, instead, display the same antiferromagnetic behaviour thus suggesting that the method used for the zeolite crystallization neutralizes the parameters responsible for raw bauxite magnetic differences.