Vitrified Light-colored Ceramic Bodies, Glazed and Porcelain Stoneware

The production of vitrified (BIb) and highly vitrified (BIa) floor tiles, which correspond to the industrial types Glazed White Stoneware (GWS) and Porcelain Stoneware, respectively, uses light-colored ceramic bodies.

With a few exceptions, all of these products are produced using a wet manufacturing process. For water absorption in the 1-3% range, GWS bodies are commonly fired at 1160-1190 °C for 35–50 min cold–to–cold.

In order to meet the market requirement of water absorption 0.1% (although the standard limit is b0.5%), porcelain stoneware tiles are typically burned at 1190–1240 °C for 50–70 min.

Big slabs (up to 360×120 cm2) as well as very thin (0.3 cm) to very thick (2.5 cm) tiles and their combination (large and thin slabs) are now produced thanks to excellent breakthrough in porcelain stoneware technology.

These huge tiles call for a special body composition with careful consideration given to the basic materials and additives used in the clay.

Studies on the firing modifications that affect LFC and light-colored bodies have also focused on how they affect the characteristics of tiles.

By using fire schedules made possible by roller kilns, light-colored vitrified bodies are created to fit the aim for water absorption while meeting all industry standards for mechanical, abrasion, frost, chemical, stain, and thermal shock resistance.

Viscous flow sintering is used to accomplish this goal because of its quick densification rates, which make it crucial to control firing shrinkage.

(recommended at b7 cm/m) and pyroplastic deformation. Most technical properties depend on the interaction between residual porosity and phase composition, particularly the vitreous phase.

Since the particular surface area produced by milling is what drives sintering, particle size distribution is stressed. Fluxes.

(sodic, potassic, alkaline-earth, and their combinations) are also a major concern since they directly affect the quantity and makeup of the vitreous phase.

Clay is used sparingly since it is the most refractory (and expensive) and iron-rich component of light-colored vitrified bodies. Its function is mainly limited to regulating technological behavior prior to firing.

In the case of illite and interstratified IS, extra flux or mullite precursor (kaolinite, pyrophyllite) make up the majority of the clay contribution during burning.

The most important factors for clay raw materials are specifically slip rheological qualities (milling and spray-drying), plasticity and compressibility (pressing), and bending strength (glazing and decorating).

Matching the needs of plasticity and strength with the requirements for slip in terms of viscosity and thixotropy (recommending low amounts of smectite and interstratified IS) requires a compromise (satisfied by a relatively high percentage of expandable clay minerals).

white stoneware:Early 1980s saw the development of glazed white stoneware by SACMI’s body No. 17, whose formulation clearly represents a break from earlier schemes:

limited use of conventional clays (25% BC), fluxes (7% sodic feldspar), and fillers (10% quartz sand), but appeal to then uncommon raw materials like low-grade kaolin (8%) and particularly “eurite” (50%) that is a sericite-feldspar flux, ensuring fusibility, ske (SACMI, 1986).

Since then, there has been a significant increase in the use of unusual raw materials, which when combined with the adaptability.

of the tilemaking process, allow for a wide range of freedom in the creation of bodies. The following basic criteria are used in this framework to create GWS batches:

Fe2O3 content of the body between 1% and 2%; clay to nonplastic raw material ratio of about 50%: 50%; preference for low to medium plasticity clays (LK, KL, BC1); opportunity to use unconventional fluxes with some clay component (e.g., RK); preference for multifunctional raw materials (e.g., raw granite acting as both flux and filler).

The following information reports a pyrophyllite-based batch together with typical recipes from the Sassuolo (Italy) and Castellón (Spain) districts as an example.

Porcelain stoneware: The best technical floor tiles are made of porcelain stoneware, which also has the best aesthetic appeal. Both UPS and GPS can be used for ventilated façades and wall coverings.

The UPS typology was created beginning with porcelain-inspired formulas, therefore early batches did not employ a lot of kaolin and little flux (i.e. PSW1 in Table 3).

Though little has changed for the GPS type, bodies more suited for fast firing were developed in the 1990s and their fundamental characteristics are still applicable (for example, PSW2 and PSW4 in Table 3).

– The average quantity of Fe2O3 in the body must be lower than 1.5%; within this range, GPS bodies show higher iron concentrations.

– The ratio of clay to non-plastic raw materials normally falls within the range of 40%:60% to 45%:55%; however, in certain specialized items, such as super white bodies, where the plastic component takes up 30-35%, it can be even lower. –

Low plasticity clays (KL, LK, PC) are used in combination with highly plastic additives (BC3 or WB); the use of BC2 with a modest amount of BC3 is indicated for big and/or thin tiles. Medium to high plasticity clays (BC1 and BC2) are selected.

Even while typical fluxes are the most common, especially in UPS batches, uncommon varieties with a clay component, such as RK, may be used if their iron concentration is low (for instance, b1%). This is particularly true in UPS batches.

– Raw materials that can serve several purposes are often well received, particularly if using them helps to lower the average cost of the batch as well as the amount of iron oxide it contains.

Additives that may be present in porcelain stoneware bodies include, for instance, plasticizers (ranging from WB to organic and hybrid binders), which are particularly.

useful for large size and/or thin tiles; sintering promoters (including talc, glass-ceramic frits, carbonates, and so on), which help to speed up densification kinetics; and so on.

Press the contact button to start negotiating. A long-term and prosperous business relationship is waiting for all importers and traders of tiles in the world with our low-price but high-quality tiles.

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