Certified Reference Material: Rare-Earth – Thorium Ore
OKA-2 was prepared from samples from a britholite deposit near Oka, Quebec. The britholite mineral has been described as thorium-bearing cerian silicate apatite. The samples were collected by the Radiation Geophysics Section, GSC in aid of an IAEA project to produce a gamma-ray spectrometry calibration standard for thorium measurements. The material was donated to CCRMP to prepare a reference material for thorium and rare earth elements, and as a source for the preparation of the IAEA material by silica dilution.
Twenty-seven laboratories in two separate measurement programs by CCRMP and IAEA provided analytical results for thorium, uranium, and potassium. Values for thorium and uranium are considered certifiable by CCRMP.
A copy of CANMET Report 86-154 (TR), "The certification of thorium and uranium in CCRMP reference material OKA-2", will be issued with each order of OKA-2.
| Constituent | |
|---|---|
| Thorium | 2.893 ± 0.058 wt% |
| Uranium | 218.6 ± 8.2 µg/g |
| Component | % |
|---|---|
| RE2O3 + Y2O3 | 33.51 |
| CaO | 25.32 |
| SiO2 | 14.72 |
| P2O5 | 8.93 |
| Fe2O3 | 5.83 |
| ThO2 | 3.292 |
| F | 1.28 |
| MgO | 1.24 |
| Al2O3 | 0.82 |
| SrO | 0.66 |
| MnO | 0.52 |
| ZnO | 0.55 |
| NiO | 0.16 |
| TiO2 | 0.62 |
| Na2O | 0.36 |
| C | 0.32 |
| U3O8 | 0.02582 |
- Sum of values for rare earth oxides determined individually.
- Certifiable values from interlaboratory measurement program.
| Constituent | Mean | wt %± 95 % C.I |
|---|---|---|
| La2O3 | 5.6 | ± 0.3 |
| CeO2 | 14.3 | ± 0.9 |
| Pr6O11 | 1.8 | ± 0.2 |
| Nd2O3 | 6.7 | ± 0.6 |
| Sm2O3 | 1.0 | ± 0.1 |
| Eu2O3 | 0.26 | ± 0.03 |
| Gd2O3 | 0.58 | ± 0.10 |
| Tb4O7 | 0.06 | ± 0.01 |
| Dy2O3 | 0.17 | ± 0.05 |
| Ho2O3 | 0.020 | ± 0.009 |
| Er2O3 | 0.06 | ± 0.06 |
| Tm2O3 | 0.002 | ± 0.002 |
| Yb2O3 | 0.011 | ± 0.005 |
| Lu2O3 | 0.0013 | ± 0.0005 |
| Y2O3 | 0.32 | ± 0.07 |
| Sc2O3 | 0.004 | ± 0.001 |
| K | 0.34 | ± 0.02 |
For further information
CCRMP, CanmetMINING
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Ottawa, ON K1A 0G1
Canada
Telephone: 343-543-6830
E-mail: Contact CCRMP