Characterization of porous clay ceramics used to remove salt from the saline soils

Abstract

This paper presents the characterization of porous argil ceramic columns used as a tool to remove salt from the saline soils. The characterization of the samples was performed before and after application for the salt extraction from the soil. Phase, chemical and microstructural characterizations of the whole series of samples were carried out by using X-ray diffraction technique (XRD), ICP-AES measurements and scanning electron microscope (SEM), respectively. Therefore, XRD revealed that quartz is the most important phase. Besides, sodium chloride (halite, NaCl) is the predominant compound formed during the desalination time. The presence of high-temperature phases in the ceramic columns such as diopside and anorthite showed the use of high firing temperatures, in the range 950–1050°C. In addition, SEM observation on cross-sections clearly showed a network of small dense zones, including quartz grains, interconnected by recrystallized porous phases. These images showed the importance of the pores dimensions and structures on the solution movement and salt deposal. Therefore, it revealed that the porosity heterogeneities could have a great impact on the location of efflorescence at the ceramic column surface. As a consequence, the obtained results allowed us to choose the suitable clay ceramic for the salt extraction from the soil.