Plasticity characterization of certain Nigeria clay minerals for their application in ceramic water filters

Abstract

Plasticity is an essential property of clay that determines its suitability for water filtration. There are no published works on the plastic behavior of clays from the study locations. The plastic behavior of seven Nigerian clays was examined using plasticity indices and compressive stress parameters in relation to chemical compositions and moisture content. The objective is to determine plastic behavior of some Nigerian clays and their suitability in production of Expanded Clay Aggregates (ECA) for water filters. Compressive stresses and deformation parameters were determined experimentally and compared theoretically. Atterberg limits (D 4318) were used to determine the plasticity indices. Chemical compositions of the samples were examined with XRF and correlated with plasticity and mineral contents of the clays. The clays are aluminosilicates with SiO2/Al2O3 ratio of 1.61 to 3.03 and plastic indices of 8 to 49. Low plastic indices (8–11) and low compressive stresses parameters were observed for kaolinite clays (0.002 MPa) due to their low affinity for water while zeolite rich clays showed high plastic indices (46 and 49) for Obowo and Minna and sharp difference in their compressive stresses parameters (0.15 and 0.03 MPa) at optimum moisture contents of 57% and 53%, respectively. Despite varying moisture content, chemical and mineral compositions, all curves showed similar trends apart from kaolinites at 40% moisture content. Relationships exist among microstructural properties, chemical composition, moisture content, compressive strength, and plasticity indices of the clays. The plastic behaviors show they are suitable for development of ECA for water filters.

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“…Achieving good plasticity is essential to ensure that the material does not show early cracking or extreme sensitivity to humidity. To obtain a balanced plasticity that can withstand the frothing pressure during backwashing in treatment plants or when using Expanded Clay Aggregates in water bottles, it is common practice to combine low-plastic clay with high-plastic clay …”

“…The plasticity of clay minerals plays a crucial role in determining the properties of CWFs, especially in pressing and extrusion methods. In a reported study, 48 the plasticity indices were determined using the Atterberg limits. The clays analyzed in the study were identified as aluminosilicates with SiO 2 /Al 2 O 3 ratios ranging from 1.61 to 3.03 and plastic indices ranging from 8 to 49.…”

“…To obtain a balanced plasticity that can withstand the frothing pressure during backwashing in treatment plants or when using Expanded Clay Aggregates in water bottles, it is common practice to combine low-plastic clay with high-plastic clay. 48 …”

“…To obtain a balanced plasticity that can withstand the frothing pressure during backwashing in treatment plants or when using Expanded Clay Aggregates in water bottles, it is common practice to combine low-plastic clay with high-plastic clay. 48 Combustible materials play a significant role in the production of ceramic water filters. Experimental results demonstrate their influence, which includes increased water plasticity, higher shrinkage rates, and filter porosity.…”