Dolomite
Scope
The measurement of CaCO₃, MgCO₃, Fe₂O₃, Al₂O₃, and SiO₂ in dolomite is demonstrated using empirical calibration.
Background
Dolomite (calcium magnesium carbonate) is mainly used as an aggregate in concrete and asphalt for building roads. During mining and processing operations, it is important to monitor and control the dolomite composition to ensure proper quality and characteristics desired for the various products. Rigaku meets this industry need with a high-performance, affordable benchtop EDXRF system. Rugged and reliable, the NEX QC+ is an ideal tool for measuring major carbonate and oxide components in dolomite, with simple and intuitive software designed for the non-technical at-line operator and for use in quality control labs.
Model: NEX QC+
Calibration
A set of 14 assayed site-specific standards were provided by an industry user for this demonstration. Regression fits are made using alpha corrections that automatically compensate for variations in X-ray absorption and enhancement effects within the sample.
| Compound | Concentration range |
| CaCO₃ | 57 – 84% |
| MgCO₃ | 15 – 40% |
| Fe₂O₃ | 0.2 – 1.0% |
| Al₂O₃ | 0.1 – 1.3% |
| SiO₂ | 0.3 – 2.2% |
Precision
Typical precision is shown here. Ten repeat analyses of each sample were performed with the sample in static position.
|
Sample: D4 |
||||
|
Compound |
Standard value |
Average value |
Std. dev |
% Relative |
|
CaCO₃ |
62.731 |
62.651 |
0.082 |
0.1 |
|
MgCO₃ |
36.476 |
36.225 |
0.121 |
0.3 |
|
Fe₂O₃ |
0.236 |
0.252 |
0.007 |
3.0 |
|
Al₂O₃ |
(0.061)* |
(0.072) |
0.006 |
9.8 |
|
SiO₂ |
0.31 |
0.3362 |
0.011 |
3.5 |
|
Sample: H14 |
||||
|
Compound |
Standard value |
Average value |
Std. dev |
% Relative |
|
CaCO₃ |
74.953 |
75.261 |
0.077 |
0.1 |
|
MgCO₃ |
23.347 |
23.147 |
0.085 |
0.4 |
|
Fe₂O₃ |
0.32 |
0.314 |
0.005 |
1.6 |
|
Al₂O₃ |
0.256 |
0.258 |
0.005 |
2.0 |
|
SiO₂ |
0.844 |
0.821 |
0.017 |
2.0 |
Conclusion
The performance shown here demonstrates NEX QC+ provides excellent sensitivity and performance for the measurement of carbonates and major oxides in dolomite. Self-contained with simple touch screen operation, NEX QC+ is an excellent tool for at- line control and quality checks throughout the mining and processing of dolomite.