Characterization and Beneficiation of Ethiopian Kaolin for use in Fabrication of Ceramic Membrane

Abstract

Kaolin (china clay) is a rock material that is very rich in kaolinite. A kaolin ore from Debre Tabor, Ethiopia containing 59.2 wt.% SiO2, 24.9 wt.% Al2O3, 2.4 wt.% Fe2O3, and 8.22 wt.% loss on ignition (LOI) was physically beneficiated, chemically leached, and thermally treated for possible industrial use, especially for ceramic membrane fabrication. The leaching experiments were carried out using oxalic acid solutions as leaching reagents for the iron extraction process. The effect of acid concentration, reaction temperature, and contact time on iron leaching was investigated. It was determined that the rate of iron extraction increased with the oxalic acid concentration, leaching temperature, and contact time. A substantial reduction of iron oxide (2.4 to 0.36 wt. %) from the raw kaolin was observed at operating conditions of 2.0 M oxalic acid, the temperature of 120°C, and contact time of 120 min. A maximum kaolin whiteness index of 81.4 % was achieved through this leaching process. Finally, the physically beneficiated, chemically leached, and thermally treated kaolin raw material was used to fabricate a low-cost kaolin-based ceramic membrane. After firing at 1100°C the ceramic membrane was found to have a mass loss of 11.04 ± 0.05%, water absorption of 8.9 ± 0.4 %, linear shrinkage of 14.5 ± 0.05%. It was demonstrated to be chemically stable, having less than 3 % mass loss in acid solution, and less than 1 % mass loss in alkali solution. The newly developed membranes have thus properties comparable to commercial ceramic membranes.

Synthesis of ceramic tubular membrane from low‐cost clay precursors for blood purification application as substitute of commercial dialysis membrane

“…However, when a PES membrane meets blood, protein from the blood is adsorbed onto the membrane's surface, causing blood cells to coagulate and platelets to adhere to the surface 27 . Ceramic‐based membranes are rapidly attaining prominence in the medical field as a solution to these problems due to their thermal efficiency, chemical stability, mechanical strength, higher separation efficiency, long lifetime and antifouling properties 28‐31 …”

Characterization and Optimization of Calcination Process Parameters for Extraction of Aluminum from Ethiopian Kaolinite

“…Several studies have been carried out on Ethiopian kaolinite for various applications such as synthesis of zeolite [28,29]; adsorbent preparation [30], and ceramic membrane synthesis [31]. However, in the authors' knowledge, the effects of calcination temperature, time, and particles size on the degree of conversion of dehydroxylation reaction of kaolinite and extraction yield of aluminum from Ethiopian kaolinite have not been investigated.…”