Bentonite-based composites with ceramic and metallic powders additions for use as filters

Abstract

This paper represents the study of bentonite matrix composite reinforced with ceramic (Al2O3 and SiC) and metallic (Al and Fe) particles for the production of filters. Ceramic powders were used to generate pores and metallic particles to control the pore size (to finish them). These materials were added to composites in two stages. In the first stage, the ceramic particles (Al2O3 and SiC) were added to the bentonite matrix, thus obtaining two types of composites. In the second stage, for each type of composite, metallic powders of Al and Fe were added. The composites was prepared by mixing the components, cold pressing for compaction in cylindrical samples and, at the end, sintering at 1250°C. The samples thus produced underwent studies by optical and electron microscopy, diffractometry, dilatometry and thermal analysis and tests to determine the compressive strength and the porosity. Thus, there was obtained useful information regarding the behaviour and impact of the reinforcing materials in the process of producing the composites, and on their impact on the final properties of the composites produced.

Study of filtering capacity of some ceramic composites on bentonite base

“…The compressive strengths are high enough to preserve the geometry and dimensions of the finished products during processing and use. They are comparable to those of materials presented in similar studies [13,17,19,20]. The average porosity of the composites obtained ranged between 15% and 25%.…”

“…Two determinations were conducted for each batch of composites, as presented in Table 2, and the average of these values is shown in Figure 2 and Figure 3. Similar values have been found in previous research [17]. The number of determinations was limited to two considering the appropriate constancy of the values.…”

“…SiC and Al2O3 ceramic powders [15] were used as reinforcement materials in order to ensure the porosity of the composites [15,16]. The higher the proportion of these particles, the thinner the layer of bentonite covering them, thus increasing the volume of the pores in the composite [17]. Al metallic powders were added to control the pore size [15][16][17][18].…”

“…The higher the proportion of these particles, the thinner the layer of bentonite covering them, thus increasing the volume of the pores in the composite [17]. Al metallic powders were added to control the pore size [15][16][17][18]. The grain size featured by SiC ceramic powders is 60-80 µm, by Al2O3 is of approximately 50 µm, and by Al metallic particles is below 65 µm [15].…”

Method of Water Filtration Using Ceramic Composite Materials Based on Bentonite

“…There were made composite materials with matrix based on bentonite powder. Bentonite is a clayey sedimentary rock formed by the degradation of volcanic tuffs and it is characterised by a high water retention capacity [7]. It consists of a mixture of clayey minerals, the main component of which is montmorillonite.…”