Sintering of sepiolite-rich by-products for the manufacture of lightweight aggregates: technological properties, thermal behavior and mineralogical changes

Abstract

A sepiolite mining by-product (SEP) has been studied as major component for lightweight aggregate (LWA) manufacture. Pellet bursting during firing was avoided by the addition of 2.5 wt% of thermoplastic waste (P) and 2.5 wt% P + 2.5 wt% carbon fiber residue (FC) in powder form. The mixtures were pelletized and then sintered at 1225º˚C for 4 minutes in a rotary kiln. Highly porous white LWAs with good mechanical strength were produced. A mineralogical study revealed the formation of amorphous phase ( > 50%) and minor proportions of enstatite, protoenstatite and diopside. Quartz was the only inherited mineral, appearing in the form of isolated phenocrysts within a general porphyritic texture. The result of this study suggests the promising use of sepiolite (whether or not in residue form) for the manufacture of high quality LWAs.

Development of Lightweight Mortars Using Sustainable Low-Density Glass Aggregates from Secondary Raw Materials

“…On the other hand, building materials have heterogeneous compositions and microstructures; therefore, they tolerate compositional variations in waste from different campaigns. In recent decades, several studies have focused on the reuse of waste as a raw material in the manufacture of different construction materials, such as various types of clinker [ 5 ], cement [ 6 , 7 , 8 ], mortars [ 9 ], concretes [ 10 , 11 , 12 , 13 ], geopolymers [ 14 , 15 ], clay bricks [ 16 , 17 , 18 , 19 , 20 ], ceramic tiles [ 21 , 22 ], and roof tiles [ 23 , 24 ].…”