The effect of clay content for pruducing alumina-based ceramic foam filters

Alumina-based ceramic foam filters were prepared by organic foam impregnation. The effect of clay content on the properties of ceramics was studied. The results show that with the increase of clay content, the thermal shock stability of the samples increases first and then decreases, and the compressive strength increases first and then decreases, and then increases slightly. When the mass fraction of clay is 6%, the performance of foam ceramics is the best. At this time, the compressive strength is 1.70 MPa, and the number of thermal shock cycles is 12.

The ceramic foam filter generally uses a polyurethane sponge as a carrier and immerses it into a slurry made of ceramic powder, binder, sintering aid, and suspending agent; Then, the excess slurry is squeezed out so that the ceramic slurry is uniformly coated on the carrier skeleton to become a green body; And then the green body is dried and sintered at high temperature. Because of its high porosity, large specific surface area, good thermal shock resistance, high-temperature resistance, chemical corrosion resistance, good mechanical strength, and filtration adsorption performance, foam ceramics can be widely used in heat exchange materials, air distribution materials, automobile exhaust gas purification devices, molten metal filtration in metallurgical industry, heat recovery, industrial sewage treatment, heat insulation, and sound insulation materials.

Alumina-based ceramic foam filters are playing a more and more important role in the filtration of molten metal aluminum. The main disadvantages of domestic products are low strength and easy slag dropping. The main reason is that the slurry composition is not well controlled, which affects the slurry quality, thus affecting the ceramic performance. Clay is an important component of ceramic slurry because of its fine particle, strong plasticity, good binding, good thixotropy, suitable shrinkage, and high fire resistance.

In alumina-based foam ceramics, clay can improve the plasticity and bonding of the slurry, and plays an indispensable role in the preparation of ceramic slurry. However, the amount of clay added in alumina-based ceramics and its influence has not been described in detail in the literature. Therefore, this paper studies the effect of clay addition on the properties of alumina-based ceramic foam filters in order to obtain better ceramic foam filters.