The Preparation and Properties of Porous Sepiolite Ceramics

Abstract

In this paper, a new type of porous ceramics was prepared using the raw sepiolite mineral. The porous ceramics was shaped by the dry pressing method and sintered in the range of 700 ~ 1200 °C. The temperature-microstructure evolution and the properties of porous sepiolite ceramics were investigated by thermo gravimetric and differential thermal analyses (TG-DTA), X-ray diffraction (XRD), bending strength, compressive strength, scanning electron microscopy (SEM) and mercury intrusion porosimeter (MIP). The sintering kinetics of the porous ceramics from sepiolite was investigated by means of stepwise isothermal dilatometry (SID). The mechanical properties improved with the increasing sintering temperature, and the bending strength and compression strength reached a maximum of 52 MPa and 32 MPa respectively at 1200 °C. The porosity increased with the sintering temperature until 1100 °C attaining the value of 55.40% and then decreased to a value of 46.48% at 1200 °C. The main crystal phases of the porous ceramics were akermanite and diopside. At 1200 °C, the pores inside the ceramics basically follows a unimodal distribution, which was mainly located near 553 nm. The sintering activation energy of porous sepiolite ceramics was measured by step isothermal thermal expansion with a value of 791.42 kJ/mol in the range of 1000 °C to 1200 °C.

Thermally insulating GdBO3 ceramics with neutron shielding performance

“…The increase in mean pore size was mainly ascribed to liquid phase sintering. Under the action of liquid phase sintering, small particles faded away and larger particles grew up, leading to the disappearance of small holes or fusion into larger pores 14 …”

Synthesis of a polymeric nanocomposite based on magnetic sepiolite functionalized with an ionic liquid for the adsorption of aromatic pollutants from aqueous solution

“…They are used as adsorbents to remove water contaminants. Sepiolite is a fibrous hydrated magnesium silicate mineral, 13,14 with a high surface area plus chemical and mechanical stability. The powerful sorbent properties of SP and its ability to adsorb organic or inorganic ions are related to the alternating blocks and tunnels growing along the microfibers.…”

Functionalized Sepiolitic Clay Nanofibers as a Natural Ingredient in Medical Cosmetics

“…These tunnels and open channels occur in the unique structure of sepiolite fibers. The shape of sepiolite clay is either fibrous or can be seen as a fiber bundle under the atomic force microscopy (5), although the length of sepiolite fibers changes from different regions (6,7). Figure 2 presents the inner tunnels and channels on the external surfaces of fibrous clays.…”