Norflux Potash Feldspar (Sibelco, K 11 / LIS D75)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Feldspars and stones
- Formula
- SiO₂ 65.9%, Al₂O₃ 18.6%, Fe₂O₃ 0.07%, TiO₂ 0.002%, CaO 0.4%, K₂O 11.8%, Na₂O 2.9%, LOI 0.14%
- Also called
- Kalifeldspat K 11, Kali-Feldspat K 11, Feldspat K 11, Kali-Feldspat Norflux LIS D75, Feldspat Kali LIS 75, Feldspat Kali (D75), Feldspar Potash K11=D75=Nk6400, Feldspath potassique Norflux K-LIS 75, Norflux, Kalifeldspat K 2/75, Norflux LHI 2, Lehmhuus Feldspat K
- Made by
- Sibelco Deutschland GmbH (Brake, Germany), sold under the Norflux name
- Sold in
- EU, UK
- Similar materials
- Potash Feldspar (Potterycrafts P3296) , G-200 EU Feldspar , Mahavir Potash Feldspar
- Source
- BSZ Keramikbedarf product page 'Feldspat Kali LIS 75' (chemical and mineral analysis)
The potash feldspar that most German pottery suppliers sell (BSZ, Carl Jäger, Keramik-Kraft, Töpferbedarf Rantzau), also sold by Lehmhuus (Switzerland), keramik.at (Austria) and Solargil (France). BSZ gives it as about 72% potash feldspar, 23% soda feldspar and 2% quartz.
Potterycrafts' P3296 data sheet (October 2025) gives this analysis, so it appears to be sold in the UK as P3296.
Oxide analysis and unity formula
Glazecalc has the analysis of Norflux Potash Feldspar (Sibelco, K 11 / LIS D75) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Norflux Potash Feldspar (Sibelco, K 11 / LIS D75) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 65.9 | 6.121 |
| Al₂O₃ | 18.6 | 1.018 |
| Fe₂O₃ | 0.07 | 0.002 |
| TiO₂ | 0.002 | 0.000 |
| CaO | 0.4 | 0.040 |
| K₂O | 11.8 | 0.699 |
| Na₂O | 2.9 | 0.261 |
- Equivalent weight
- 558.05
- Fired weight
- 557.27
- Loss on ignition
- 0.14%
The equivalent weight is the grams of Norflux Potash Feldspar (Sibelco, K 11 / LIS D75) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Sibelco's safety data sheet (2024-03) does not classify it and gives fine quartz below 1%, with up to 25% nepheline syenite in the mix. Avoid breathing the dust.
Use it in a recipe
Add Norflux Potash Feldspar (Sibelco, K 11 / LIS D75) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.