Feldespato potásico M (Prodesco)
A standard material in Glazecalc's library: its oxide analysis, unity contribution and hazards.
What it is
- Kind
- Feldspars and stones
- Formula
- SiO₂ 69.86%, Al₂O₃ 16.16%, Na₂O 3.75%, K₂O 7.51%, CaO 0.33%, MgO 0.05%, TiO₂ 0.08%, Fe₂O₃ 0.16%, LOI 2.1%
- Also called
- Feldespato potásico, Feldespato potásico "M", Prodesco 50101500
- Made by
- Sold under the Prodesco S.L. brand (Manises, Valencia, Spain); the mine is not stated
- Sold in
- EU
- Similar materials
- FFF Feldspar (Sibelco FFF K7-60)
- Source
- Prodesco technical sheet 'Feldespato potásico "M"', code 50101500, v1.5 (04/06/2026) (2026-06)
The potash feldspar of Spain's main pottery raw-material brand. Despite its name it carries only 7.5% K2O with 3.75% Na2O and extra silica, so it is a weaker flux than a true potash spar.
Oxide analysis and unity formula
Glazecalc has the analysis of Feldespato potásico M (Prodesco) as weight percent of the raw material. The unity contribution is the moles of each oxide in the amount of Feldespato potásico M (Prodesco) that holds 1.0 mole of flux, which is how Glazecalc adds it into a recipe's unity formula.
| Oxide | Weight % | Unity contribution |
|---|---|---|
| SiO₂ | 69.86 | 7.890 |
| Al₂O₃ | 16.16 | 1.076 |
| Na₂O | 3.75 | 0.411 |
| K₂O | 7.51 | 0.541 |
| CaO | 0.33 | 0.040 |
| MgO | 0.05 | 0.008 |
| TiO₂ | 0.08 | 0.007 |
| Fe₂O₃ | 0.16 | 0.007 |
- Equivalent weight
- 678.62
- Fired weight
- 664.37
- Loss on ignition
- 2.1%
The equivalent weight is the grams of Feldespato potásico M (Prodesco) that hold 1.0 mole of flux. The fired weight is what is left of that after firing.
Hazards and safety
Hazards: Fine dust contains respirable crystalline silica; avoid breathing it.
Use it in a recipe
Add Feldespato potásico M (Prodesco) to a recipe in the Glazecalc calculator to see what it does to a glaze's unity formula.