Having a less fragile clay body after the tile is pressed is not only down to buying expensive high plasticity clay. There are workarounds to increase the Ceramic Green Strength without emptying your pockets. Read on to find a solution that fits your production.
Ceramic Green Strength is defined as a body's ability to withstand handling, molding or machining before completely cured or hardened. Stronger products in this phase of the production reduce costs in several ways:
- Less breakage
- Faster drying time
- Safer drying process
- Reduced rejection
- Cleaner environment
The better green strength comes with high-quality clay due to the great clay plasticity. Given the astronomical prices these raw materials have reached the last few years, creative thinking and decent craftsmanship produce highly appreciated alternatives:
1. Adjust the formulation
Typically, the balance between plastics and non-plastics will allow working in much safer conditions, but potentially with a higher cost of raw materials.
2. Testing other raw materials
Not all the raw materials have been explored, and potential higher share of Kaolins, Kaolinitic Clays, Talcs, etc. are feasible and recommendable.
3. Improving particle size distribution
When working with higher density, the best performance in green strength is achieved, though in some cases, we can see some negative effect on the drying process. More dense products have a lower permeability and water has a tougher way out of the clay matrix.
4. Use clay additives that have plasticizing effect
Plasticizers have been utilized in the industry for many years, being also more present now that the green chemicals play a more important role. There are two categories of plasticizers in the ceramic industry:
First, dispersing agents used in the industry for wet clay grinding were based on inorganic salts. Phosphates had a significant share then. Due to its cost variability and its high impact on the rheology of the slurries, hence in the final product, their popularity diminished.
In most of the cases, dispersants based on Polycarboxylic derivatives are used in the wet grinding stage. Some others are also used, but not so frequently.The industry is trying to reduce their carbon footprint, keeping an equivalent performance or, even improving it, while compensating emissions of CO2. That is why new developments come from Green Additives.
As I mentioned, the relation between Ceramic Green Strength and cost reduction is evident. The market demands for larger tiles further expand the economic gain potential. More clay per tile means more costs for each crack, deformation or unevenness. We have seen manufacturers increasing their output from 5 to 10 percent depending on the method of choice.
Aside from the economical aspect, increased Green Strength reduces the amount of raw materials in the process and the emissions to the environment. We are all responsible for keeping our environment clean and healthy for the next generations.
The big picture is that the line and the premises of every production plant are given. Experimenting with the input to the process is therefore of high value.