SN/T 5248-2020 in English
VALIDDetermination of gold in imported gold loaded resin materials-Flame atomic absorption spectrometry
- Issued on:2020-08-27
- Implemented on:2021-03-01
- File Format:PDF
- Delivery:Via email within 1~3 business days
$97.00
Introduction
Interpretation of the core content of the standard
This standard replaces SN/T 0654-1997. The main technical changes include: sample pretreatment is optimized to 650℃ incineration in a high-temperature furnace to remove impurities, an innovative enrichment method of foam plastic adsorption combined with thiourea release is adopted, and the precision control requirement is increased by 20%.
Method principle and technological evolution
| Technical elements | 1997 edition | 2020 edition | Improvement effect |
|---|---|---|---|
| Pretreatment temperature | 500℃ | 650℃ | More thorough removal of organic matter |
| Enrichment method | Activated carbon adsorption | Foam plastic adsorption | Adsorption rate increased to 98% |
| Detection limit | 0.5μg/g | 0.2μg/g | Improved sensitivity |
Key operating points
Sample treatment:The burning temperature must be controlled at 650±10℃. Too low a temperature will result in sulfide residues, while too high a temperature may cause gold loss. A laboratory comparative test showed that 700℃ treatment would result in a 3.2% decrease in gold recovery.
Adsorption control:The foam plastic needs to be activated by boiling with sodium hydroxide, and the oscillation adsorption time is strictly controlled at 30±1 minutes. Actual cases show that 25 minutes of adsorption will result in a low-concentration sample recovery rate of less than 90%.
Implementation suggestions
1. Quality control: Each batch of samples should be accompanied by standard substances (GBW07294) for process control. It is recommended to add 10% parallel samples
2. Instrument calibration: Atomic absorption spectrometer needs to be drift-corrected daily with blank solution and 2.0μg/mL standard solution
3. Interference elimination: When the copper content of the sample is greater than 500μg/g, an equivalent copper matrix needs to be added to the standard curve
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