This document summarizes Sibelco's range of performance flux minerals for sanitaryware glazes. It describes how their minerals have been formulated to provide consistent performance and optimize glaze quality. Their minerals ensure optimal sintering and fusion points while maintaining good glaze flow and surface finish. The minerals include Spectrum, Quantum, Maxum, and FFF, which offer a high level of fluxing oxides, low color content, and wide range of flux ratios. They are well-suited for use as the sole flux or in combination with other feldspars. The minerals can improve glaze aesthetics and reduce defects by providing low color, consistency, efficient fluxing, and increased fusion. Formulations using the

1. Performance Flux Minerals
for sanitaryware glazes
improve glaze quality with optimised fluxing performance

2. Engineered flux minerals for
optimised sanitaryware glazes
The 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
Recommended applications
Vitreous China Fine Fire Clay &
Product Relative Fluxing ability
Glazes Gres Glazes
Spectrum  
Quantum  
* Based on
Maxum   molar R2O
quantity
FFF  
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
Chemical and Analytical Data - Typical values which do not represent a specification
Spectrum Spectrum Quantum Maxum
unit FFF
(Canada) (Norway) (high potash) (high soda)
SiO2 Mass % 60.2 55.4 66.6 70.8 69.1
Al2O3 Mass % 23.6 24.6 18.3 18.1 18.1
Fe2O3 Mass % 0.08 0.1 0.1 0.05 0.08
CaO Mass % 0.35 1.2 0.24 0.02 0.7
These products
MgO Mass % 0.02 0.1 0.02 0.07 0.1 are available
bulk and ground
TiO2 Mass % 0.01 0.06 0.01 0.04 0.1 with a full range
K2O Mass % 4.8 8.9 10.9 0.2 6.0 of technical
data available
Na2O Mass % 10.5 8.2 3.3 10.3 5.8 from your local
Sibelco office
Loss on Ignition % 0.4 0.9 0.4 0.2 0.3

3. 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 batch
If 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 Spectrum Quantum Maxum
FFF
(Canada) (Norway) (high potash) (high soda)
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:Na2O 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 aesthetics
If 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 Spectrum Quantum Maxum
FFF
(Canada) (Norway) (high potash) (high soda)
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 defects
As 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

4. everything flows, nothing stands still
Heraclitus
Sibelco
Quellinstraat 49
2018 ANTWERPEN Belgium
For further information please email:
qualityceramics@sibelco.com www.sibelcoceramics.com