The pressing stage is one of the most demanding in the production of ceramic bodies. Therefore, gaining any improvements here is directly translated into savings along the production process. These improvements will help to optimize the total costs of the manufactured products by reducing losses whilst improving the quality of the shaped materials.
how plastic is your formulation?
One of the main differences between the ceramic bodies that can be manufactured through the pressing process is related to their plasticity. We can separate between “plastic” and “non-plastic”.
- Any of the formulations including clay can be considered as plastic. Of course, there will be differences between plasticity, depending on the other components of the formulation, but they will become plastic once some pressure is applied during the pressing stage.
- Non-plastic. A typical example of these formulations could be any of the basic refractory bricks or any of the “clay-free” state-of-the-art developments for lightweight ceramic tiles. These are characterized by not having any clay in their formulas, hence a requirement for plastic components. The need for these plastic components are initially necessary for keeping the shape of the specimens after pressing but as shape and size increase against todays demand then the need for these components will become even bigger. As such, this is the point where additives can make their “magic”.
How can additives improve plasticity?
Basically, most additives are interacting with the surface of the different components of the formulas. Although it may not be a strong interaction it is strong enough to enable those different materials to flow by reducing their inter-particular bonds. It can be seen in the following picture:
This effect allows formulations to behave in the same way as if the water share in the total formula was much higher. Therefore, we can say that these additives improve plasticity.
how is lubrication being improved?
The presence of Biopolymers on the surface of the particles in the formulation generates the same effect as if plasticity was improved, but without using any plastic raw material or any water addition.
When pressure is applied in the press, particles flow much easier and their apparent compaction values are much higher when applying the same forces. Furthermore, there are some Biopolymers, also known as binders, in the market that allow particles to remain “bonded” when some pressure is applied which in turn helps to keep the facilities clean, as there is no particle release.
A secondary effect on the same particles is that, as long as they are not released, pressing moulds remain clean and the number of cleaning breaks is also reduced, increasing the yield of the machine.
If we consider the potential existence of some products capable of acting both as binders and dispersants, we have the perfect solution for improving the pressing stage in the shaping process within the Ceramic Industry.