Performance Flux Minerals for sanitaryware glazes

improve glaze quality with optimised fluxing performance

Engineered flux minerals for optimised sanitaryware glazesThe full range of Sibelco glaze fluxes have been formulated and processed to give exceptional performance in sanitaryware glaze systems and with Sibelco’s commitment to quality the variation between batches is minimal; ensuring consistent manufacturing results for the user.Our range of sanitaryware glaze fluxing minerals is ideal for ensuring optimum sintering and fusion points are reached in glaze applications, whilst maintaining good glaze flow ability combined with a high quality surface finish even in frit, barium and zinc free formulations.Sibelco’s unique range of glaze flux minerals includes Spectrum (Nepheline syenite), FFF (mixed feldspar), Maxum (sodium feldspar) and Quantum (Potassium Feldspar). With such a wide range of minerals available the portfolio can meet the needs of most manufacturing formulations.The key features of the range are:

• A high level of fluxing oxides• Low colouring oxide content• Wide range of flux oxide ratios from pure soda and potash to mixed combinations• Unique mineralogy

Ideally suited to being the sole flux in sanitaryware glaze systems, or mixed with other feldspars to enhance current performance

Chemical and Analytical Data - Typical values which do not represent a specification

unitSpectrum(Canada)

Spectrum(Norway)

Quantum(high potash)

Maxum(high soda)

FFF

SiO2

Mass % 60.2 55.4 66.6 70.8 69.1

Al2O

3Mass % 23.6 24.6 18.3 18.1 18.1

Fe2O

3Mass % 0.08 0.1 0.1 0.05 0.08

CaO Mass % 0.35 1.2 0.24 0.02 0.7

MgO Mass % 0.02 0.1 0.02 0.07 0.1

TiO2

Mass % 0.01 0.06 0.01 0.04 0.1

K2O Mass % 4.8 8.9 10.9 0.2 6.0

Na2O Mass % 10.5 8.2 3.3 10.3 5.8

Loss on Ignition % 0.4 0.9 0.4 0.2 0.3

The performance flux minerals from Sibelco are highly suited for manufacturing low colouring oxide, low defect glazes and combined with a selection of fusibility profiles make them highly suited to a wide range of sanitaryware firing conditions. Our performance flux products can benefit customer production processes by improving end glaze aesthetics and helping assist in the reduction of traditional glaze defects due to:

• Low colouring oxide = exceptional white colour which can assist in the reduction of Zircon in the glaze formula• Consistency = Less glaze batch variation and improved colour matching• High fluxing oxides = Efficient fluxing• Unique Mineralogy1 = Increased fusion

1 Nepheline based products

Recommended applications

ProductVitreous China

GlazesFine Fire Clay &

Gres GlazesRelative Fluxing ability

Spectrum

Quantum

Maxum

FFF

* Based on molar R2O quantity

These products are available bulk and ground with a full range of technical data available from your local Sibelco office

The Performance flux mineral product range offers significant advantages for sanitaryware glaze manufacture:

1. A wide range of fusibility which can assist in reducing the amount of overall imported flux in the glaze batchIf we consider a typical European sanitaryware glaze chemistry, adjusting the batch recipe to keep the same molar R2O content; then the following formulations are obtained with Sibelco’s range of Feldspathic materials.

Formulations Spectrum(Canada)

Spectrum(Norway)

Quantum(high potash)

Maxum(high soda)

FFF

Spectrum (Canada) 31.9 - - - -

Spectrum (Norway) - 31.5 - - -

FFF - - - - 44.6

Maxum - - - 41.7 -

Quantum - - 41.5 - -

Quartz 18.1 21.0 10.8 10.7 8.8

Kaolin 10.3 9.2 9.3 8.1 8.3

Zircon 15.8 15.6 15.4 15.8 15.5

Wollastonite 19.8 18.7 19.2 19.8 19.0

Talc 3.7 3.7 3.5 3.7 3.5

Binder 0.3 0.3 0.3 0.3 0.3

TOTAL 100 100 100 100 100

K2O:Na

2O Ratio 1:1.8 1.2:1 2.3:1 1:22.5 1.1:1

Typicaly 25% less feldspathic material is required when using the Spectrum range due to their high alkali and alumina content.

2. Low colouring oxides to assist in the attainment of high whiteness glaze aestheticsIf we consider the quality of the glaze produced, we can see that, due to the low colouring oxides in Sibelco Glaze Feldspathic materials, they all produce high whiteness glazes.

Colour Spectrum(Canada)

Spectrum(Norway)

Quantum(high potash)

Maxum(high soda)

FFF

L 93.35 93.85 93.5 92.67 93.14

a* -0.46 -0.55 -0.47 -0.33 -0.23

b* 2.09 2.17 1.92 2.02 2.06

3. Improved glaze flow and optimised sintering which can assist with improved degassing and lower glaze surface defectsAs the sodium oxide content reduces, in favour of potassium oxide, the glaze sintering/fusion point decreases, and conversely, as the potassium oxide content reduces, the glaze flow increases. This occurs until a minima is reached at the sodium/potassium eutectic, before rising again at high potassium ratios. Thus, a grade (or combinations of grades) can be selected that optimises the degassing of the body and flow of glaze that suits all sanitaryware glaze needs.

3.1 Effect of Na:K ratio on glaze fusion temperature 3.2 Effect of Na:K ratio on glaze flow

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