effect of calcium carbonate addition on the properties of mullite ceramic membrane

In this research, the effects of adding calcium carbonate to kaolin for microfiltration membranes have been investigated. the extrusion procedure was used to prepare 4 types of membrane samples, with an inner diameter of 10 mm, outer diameter of 14 mm, and the length of 25 cm, which were prepared with different concentrations of kaolin and calcium carbonate and then sintered at 1,250 °c in an electrical furnace. to investigate the morphology, crystallization as well as phases formation, and mechanical strength of as-prepared membranes, scanning electron microscopy (sem), x-ray diffraction (xrd), and tensile analysis were conducted, respectively. the results of porosity analysis exhibited the decomposition of calcium carbonate at 800 °c, which had a significant effect on increasing the porosity of the membranes. as a result, after sintering, the mc membrane (85-15) with a promising mechanical strength of 13.5 mpa enjoys a 55% of porosity and 0.306 µm average pore size.