Apparently invisible. Chemistry in ceramics.

The episode focuses on a subject that may seem unimportant but that, instead, is quite relevant if we consider the recent and new intended use of ceramic surfaces (tables, countertops, etc). Since tiles now are used not only for floors and walls (but also for furniture: tables, top, countertops, ect) the contact with the food we eat is frequent and it must be considered. Given that ceramics are, b...

This episode is the second part of a general overview about the most important categories of chemicals for ceramic prodution and their positive role in terms of environmental impact. The perspective wants to scratch - with a deliberately provocatory approach - the idea that chemistry cannot provide, by nature, any environmental benefit. Actually, if we addressed the subject by using a "magnifiying...

The episode aims to refocus, from a special and provocative perspective, the role of chemicals used in ceramics: from the beginning to the end of the process, that is from the grinding of the clays that form the basis of the ceramic mixture up to the firing cycle. The reading filter is "chemicals and environmental impact" and the goal is to break the preconception about the word "chemistry", often...

Ceramic glazes can be applied by means of several technologies but the most common and popular is the airless spray system.  However, sometimes glazes can still be discharged on the raw tile by means of bell or vela systems. Each application system requires different evaluations about the glaze's rheology. The glaze must be marked by specific properties according to the system with which it is app...

In Ceramics, the water-based digital system is a very important topic of interest. The R&D departments of all players have been doing research for some time, trying to improve the sector with a technology that is already widely used in many other fields of the industrial production.  Technical problems of both application machines and products (such as inks and glues) seem to be over, and the...

In ceramic production, the use of digital glues for glaze and grit applications has almost completely replaced the spray/airless application system. Even if each glue differently acts on glass powders and grits, there are two main categories that must be considered: solvent-based digital glues (based on non polar solvents) and water-based digital glues (based polar solvents and water). This episod...

The black core is a localized area marked by a brown/black (or even white) color, clearly visible in the thickness of the ceramic tile. Its presence is usually sign of inadequate oxidation and it has not to be considered as a defect that compromises the product functionality. However it's a very serious aesthetic problem, especially if we consider the increasingly different intended use of ceramic...

After introducing the topic in the previous episode and getting into the details of the problems that may arise before the inkjet application, this new episode focuses on the repellency phenomena that occur after the digital printing process at the interface between the solvent-based inks and the subsequent watery applications of glaze or grit suspensions. The different chemical nature of the inks...

The ink-jet decoration - that has replaced traditional decoration systems - has removed several problems bringing out, however, new and more complex critical issues. The new scenario has forced a different attention to all those applications that occur along the glazing line both before and after the digital printing process. In particular, the different nature of the solvent-based inks, with resp...

The ceramic mixture usually used in ceramic production, largely consists of inorganic raw materials (clay, feldspar, sand, etc.), grinding water and chemical. These mixtures, since they must be properly managed in the various stages of the production process - from grinding to pressing (or forming) - must be marked by specific and particular features. In addition to this, the raw ceramic material,...

In ceramic, the drying process takes place inside dryers where raw tiles are placed on metal supports (roller stands) for a preset time, until the residual humidity's percentage is close to 0%. The heating to which the ceramic body is subjected leads to a migration of the water molecules and so to their evaporation. Sometimes this process can be not completely homogeneous over the entire surface o...

In the previous episode, we offered a general overview on the most important chemicals normally used for ceramic glaze applications. We went deeper by addressing all those categories that are used during the preparatory step, that is the grinding stage, moving later towards the glazing line where we focused on the so-called binders for glazes. This episode closes the subject with a panorama about...

The ceramic glaze application that takes place along the glazing line is one of the most delicate steps of the ceramic production process. If you want to get high performances in terms of process and product, the glaze must be marked by proper rheological features that always change according to the application conditions of the production line. The right formulation of glaze suspensions, therefor...

In ceramic production, grit applications are mainly "wet applications" made by means of airless spraying systems. A kind of application that involves a huge amount of water within which the grit is suspended. Nevertheless, in recent time a different application method is spreading. We could define it as a dry method that, however, has nothing to do with digital systems (that involve, instead, the...

In the field of ceramics, glazes are usually applied on the raw tile by means of spray “analogical” systems (airless application system). Nevertheless, recently some new application machines have appeared on the market. They cannot be defined as completely digital but they cannot even be comparable to traditional analogue techniques. How do they work? What kind of features should the glaze have to...

Along the ceramic production line that from the pressing stage leads to the kilns, raw tiles (still delicate and fragile) often undergo to stresses on the conveyor roller that can compromise them. Chipping or breakage may occur if no preventive action is taken to increase the material's mechanical resistance. What does the mechanical resistance value mean? How do chemicals used to increase it work...

The ceramic production process - after the early stages that from the formation of the tile under the press lead to the applications of the glazing line - usually involves a final application of grit or glaze. Sometimes in huge amount. If you do not meet the proper parameters of the process, this application can lead to several problems able to compromise the ceramic surface, both technically and...

In the ceramic tiles prodcution, engobes, grits, and glazes are still applied - to a large extent - by means of airless spray systems. chine is equipped with spraying guns that end with special nozzles that properly discharge the suspension on the raw ceramic surface. Sometimes these nozzles can be clogged during application stage, forcing producers to slow down or even stop the production cycle....

The lapping and polishing processes that provide ceramic tiles with the proper aesthetic features, both involve the removal of a very thin layer of glaze that is on the very external part of the tile. Even if the amount of removed material is very small, these processes may bring out to the surface all that micro-porosity that are inside the glaze. Since they are no more protected and sealed, the...

Process water play a very important role within ceramic activities, being involved in a wide range of production’s steps. If on the one hand they are strictly necessary to the course of the work, they can lead on the other hand to problems when they do not fits the required production parameters. The fourth episode of the podcast APPARENTLY INVISIBLE. CHEMISTRY IN CERAMIC, now available on the lea...

During their storage in the tanks, semi-finished products can be affected by bacterial degradations that, if they are not properly managed, may lead to application critical issues as well as to serious defects in the finished tile product, such as pinholes Just to give an example. What kind of action must be taken to face the problem? Is it possible to restore the right features of a bacterially c...

The gelling phenomena of slurries inside the storage tanks is not so unusual as one might suppose. Let’s find out the causes and identify possible solutions.

Why do tiles explode within the kiln? The phenomena that occur inside the kiln is quite similar to those that develops inside a pressure cooker: pressure > that generates an expansion > that develops a deformation > that leads to an explosion. When this happens, companies have to stop the production process wtih serious economic consequences. What do you need to know to prevent, or at lea...

The role of chemistry in ceramic production. What are the mechanisms behind the several steps of the ceramic production process? What are the main problems that can arise and what answers can chemistry offer to solve or, at least, contain them? APPARENTLY INVISIBLE is a long journey through the ceramic production lines, between problems and solutions. At each stage a topic For each topic a critica...