Experimental Petrology and Metallurgy/Starting materials
Preparing starting mixes
[edit | edit source]Synthetic compounds
[edit | edit source]| Component (mostly oxides) | Added as | Motivation | Notes |
|---|---|---|---|
| Na2O | Na2CO3 | Oxide hygroscopic | -- |
| CaO | CaCO3 | Oxide hygroscopic | -- |
| K2O | K2CO3 | Oxide hygroscopic | -- |
| FeO | Fe2O3 | Oxide non-stoichiometric | -- |
| MgO | MgO / Mg2SiO4 | Oxide hygroscopic | -- |
| Al2O3 | Al2O3 | Fire at 1000 C before weighing | -- |
| Cr2O3 | Cr2O3 | Fire at 1000 C before weighing | -- |
| SiO2 | SiO2 | Fire at 1000 C before weighing | -- |
| P2O5 | Ca3(PO4)2 | Very hygroscopic | -- |
| CO2 | Carbonates (see above) | Heat gently before weighing. MgCO3 should be natural magnesite, as excess water is impossible to drive off the structure. | -- |
| H2O | Mg(OH)2, Al(OH)3, PtO2.4H2O | Liquid water difficult to weigh | -- |
Decarbonation
[edit | edit source]- Put powders into a crucible
- Place in 1 atm furnace at room temperature
- Heat slowly (over at least two hours to avoid spitting during decarbonation) to around 200 K above decarbonation temperature.
Gas mixing
[edit | edit source]Pelletisation
Gas mixing with H2-CO or CO-CO2. Make sure there is >20 mol% of both gases to ensure good control of fO2.