Overcome the challenges when making tiles with low plasticity clays

The clay does not last forever and, with limited deposits and high market demands, the best clay is very expensive. What would an endless source of raw material do to the prices of decorative tiles? Let's think about it and ask ourselves, how do the prices on high-quality clay dictate the market? Understanding this, might make us more open to the idea of doing things differently, be less dependent on expensive clay, thus reducing your production costs.

LOW PLASTICITY CLAY? NO PROBLEM

The single most important property of raw material in tile production is plasticity. Unfortunately, the global reservoirs have limited amounts of clay with this quality. Lots of local clay may have excellent properties, but very often plasticity is not one of those. Given the market situation,  many manufacturers are forced to use local clay and need to find ways to overcome the lack of plasticity. When using their creativity, they have had remarkable results from adapting the production process to the new reality. I will discuss how to deal with this challenge and give you an insider's view from a scientific research we conducted for one of our clients. 

USE LOCAL CLAY AND GET THE BEST OUT OF IT

Even though locally available raw materials may not deliver the desired quality, there are ways to improve the manufactured ceramic products.

Some local raw materials may present a decent whiteness, but it is typically associated with lack of plasticity. Using additives is an excellent way to bring it to optimal working values.

The addition of plasticizers is one option, the most preferred one in the industry. Among others, organic biopolymers are the most cost-effective additives, though they typically require some balance in the formulas to keep original values of:

• Green Strength: In some cases, low plasticity clays also have a much lower green strength. Biopolymers can restore it to standard values.
• Final product performance: Among other properties, water absorption and fired modulus of rupture can be affected when using lower quality clays. Additives can minimize the impact on these parameters.
• Whiteness: It is the most critical parameter, since cheaper clays typically do not perform as well as the more expensive ones. Additives may help, but not solve the problem completely.

For raw materials with excellent properties, for instance very white, we use additives to increase clay plasticity then balancing the formulation at the end.

The formulation needs to have all three components. The point is what to put in, and it will affect:

• whiteness
• green strength
• final product 

CASE STUDY

We took the biopolymer additive to test at one of our clients. At Turkish SAM, we conducted a scientific study on the effects of plasticity in local clays, from the use of biopolymer clay additives. The results were outstanding. You can download the complete study by clicking on this link, but I will give you the most significant benefits the study revealed: 

• Dried strength values were increased 20-40% for porcelain tile body and 30-50% for wall tile body, with the addition of Biopolymers.
• Technological properties of the fired bodies, both porcelain and wall tile, prepared with Biopolymers, were similar to the properties of the standard bodies.
• Technological properties of the bodies prepared without Ukrainian clay and Biopolymers, compared to standard bodies including Ukrainian clay, were similar as well. 

The study shows the potential of utilizing local clays in big size tile production. With such success, the client has solved their raw material issues and can keep a sound revenue.  

Though local clays are as different as local customs, the potential of this source should be investigated by every tile manufacturer. Remember that you can ask us for technical guidance and we will be very pleased to help. 

If you have any question, ask us here.