All waters used in ceramic processes, both tap and well water, contain bacteria and microorganisms.
The same goes for the inorganic raw materials involved in the milling process: frits, clays, feldspar, nefeline, etc…

On this basis, bacterial proliferations can potentially attack ceramic companies’ milling departments, being a natural environment of microorganisms able to assault glues, additives as well as the glaze’s organic material in suspension within the grinding mills.

This already complex set-up may get worse because of the process’ temperature. The heat produced during the milling process is usually very high: the more the heat increases the more bacterial proliferations may occur.

This is why the milling department’s equipment – mills, tanks, plumbing, etc. – are often contaminated.
The person in charge of the process only notices the problem when the degradation has already reached a high level, both on the visual and odour level. 
At this point, the all system is tainted. If nothing is done promptly, bacteria are constantly fed by using the organic products needed in the milling process.

The only possibility to avoid a rapid degradation is to sanitize the whole department.

What happen to the glaze, when the degradation is in progress?

Ceramic glazes contain, binding, levelling and fluidifying agents, as well as rheology modifiers so to get the correct rhelogical properties.
When polymers and organic additives are attacked and destroyed by microorganisms, the glaze looses its own characteristics leading to application and production problems.

Following here some of the most significant issues:

• Difficulties in maintaining the glaze in suspension 
• Lack of cohesion
• Very short drying times
• Wrong levelling 
• Possible defects after firing cycle

It is therefore clear how exceptionally important is that ceramic companies provide for a prevention protocol in order to take action before the problem arises. Given also that each company set up the milling department according to its personal needs, chemical companies must create tailor-made systems containing the appropriate biocides and sanitizer that can properly restore the unit. 

In doing so, they have to take in consideration inter alia:

• The level of water contamination
• The level of raw material contamination
• The type of tanks within which the glaze is located
• The milling times
• The storage times