APPLICATION NOTE

OREAS-354 Zinc Concentrate

SUMMARY

This application note is for the digestion of OREAS-354, a Zinc Concentrate.

Instrument:ColdBlock CB15S sample digester technology, chiller, ICP-OES
Published:August 2022
Digestion Time:20 Minutes
Acid Used:Reverse Aqua Regia
Average ColdBlock Recovery vs. CRM:
  • 100% Zinc
  • 103% Lead
  • 99% Sulfur

METHODOLOGY

  1. Chiller temperature was set to -5°C
  2. 0.25g of OREAS-354 was weighed and placed into a ColdBlock digestion vessel
  3. 20mL of Reverse Aqua Regia was added (HNO3 is added first, followed by the HCl)
  4. Sample was digested at 80% power for 20 minutes
  5. Sample was cooled and bulked to 50mL using 2% HNO3 v/v

DISCUSSION

  • Upon addition of HNO3, the evolution of reddish brown (N02) fumes occurred
  • After 20 minutes, the samples are green in color and the digested solution appears slightly opaque
  • After bulking up, a minor amount of material settled on the bottom of the tube
  • Hydrofluoric Acid can be added for a near total digestion to improve the recoveries of certain elements
  • Boric acid can also be added to re-solubilize any insoluble fluorides and help neutralize any remaining
  • For improved silver recoveries bulk up using a solution of >20% HClv/v

OREAS 354 is a certified reference material (CRM) sourced from zinc sulphide concentrate samples taken from the Dugald River metallurgical plant. The Dugald River deposit is located in the Mt Isa Inlier, ~65km north-west of Cloncurry in north-west Queensland, Australia.

Results

Table: Results of Reverse Aqua Regia Digestion

Elements

Expected Value

ColdBlock Value 1

ColdBlock Value 2

Average ColdBlock Values

% RSD

% Recovery

Zn wt. %

49.3

49.0

49.7

49.4

0.7%

100%

Pb wt. %

1.58

1.61

1.63

1.62

0.6%

103%

S wt. %

26.63

26.03

26.67

26.35

1.2%

99%

Cd ppm

1157

1116

1139

1127.5

1.0%

97%

Cu ppm

1387

1242

1278

1260

1.4%

91%

Fe wt. %

9.82

9.41

9.49

9.45

0.4%

96%

Mg ppm

540

488

516

502.0

2.8%

93%

Mn wt. %

1.54

1.48

1.49

1.485

0.3%

96%

Ag ppm

98

89

87

88

1.1%

90%

Click here to download the Application Note in PDF format.

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