[2] Basically the filter works to separates solid-liquid mixtures by removing the water from mineral concentrates and moulding the feed slurries into pellets.
[2] The pelletizing of the slurries is done by adding some solid matter to the sewage sludge so that water can be easily removed from the mixture.
The main advantage over other filtration systems is the reduction in energy consumption, up to 90% because no air flows through the discs[4] due to the use of capillary force acting on the pores.
Air breakthrough is prevented by the fine pores of the filter, thus allowing retention of higher vacuum levels.
[8] Whilst the vacuum ceramic filter has proved to be a great innovation, there are still some limitations involved when operating the equipment.
This raises the short-term negative pressure and induces dilute acid due to the falling suck phenomenon.
The coarse part of the equipment provides mechanical strength to its structure while the intermediate layer acts as a membrane carrier.
The time available for this stage depends on two factors, the rotation speed of the disc and the height of the slurry level in the basin.
[12] Stage 4: Cake discharge These are the typical conditions for the overall operation of the vacuum ceramic filter: The most important operating parameters of disc filters are the height of the slurry tank, agitation and the intensity and rotation speed of the disc as these will determine the cake formation and drying times.
Excessively high agitation intensity may affect cake formation or change the particle size distribution of the product.
However, this causes larger air volumes to be consumed at discharge due to reduced resistance and marginally lower cake moisture.
Filtrate is used to flush the disc during back flow washing to clean the micro-porous structure and remove any residual cake.
[12] The porosity of this type of ceramic can be varied from 20% to 60% by volume, which allows a low-pressure drop of liquid and gas flow.
The residuals moisture are removed from the filter cake due to capillary action within the ceramic elements, which rotate above the slurry level.
This process gives maximum filtration, and the final cake can be maintained at the lowest moisture content due to the effective cleaning of both ceramic sectors.
In addition, performance can be optimized by using an ultrasonic cleaning system to achieve efficient operation conditions[15] for regeneration of plates.
Ceramic scraper knives have been introduced to this design as they are able to shave through the mass formed in filter cake dewatering.