OREAS 504b- Porphyry Copper-Gold

APPLICATION NOTE

SUMMARY

The application note summarizes the aqua regia digestion of OREAS 504b, a porphyry copper-gold ore certified reference material using ColdBlock™ Digestion Pro Series Technology.

Instrument:	ColdBlock CBM sample digester, chiller, ICP-OES (Au by ICP-MS)
Published:	July 2026
Digestion Time:	20 minutes
Acid Used:	HNO₃, HCl
Average ColdBlock Recovery vs. CRM:	• 97% Gold • 101% Copper

Related Resources

Copper Concentrate – AMIS-0566

Copper Concentrate, CCu-1f

Copper-Gold-Silver Concentrate – OREAS-990B

Porphyry Copper-Gold – OREAS 503c

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METHODOLOGY

The chiller temperature was set to -5 °C.
Approximately 0.5 g of each sample was accurately weighed and transferred into a ColdBlock digestion vessel.
20 mL of aqua regia (HCl:HNO₃, 3:1 _v/v) was added to each vessel.
Samples were digested at 70 % power for 1200 seconds (20 minutes).
Digestates were allowed to cool, then quantitatively diluted to a final volume of 50 mL using ultrapure Type 1 water.

Figure 1. OREAS 504b digestates following ColdBlock
aqua regia digestion, prior to ICP/ICP-MS analysis.

DISCUSSION

Gold was measured by an Agilent 7850 ICP-MS using helium collision cell mode
Across the 23 quantified elements, ColdBlock aqua regia digestion of OREAS 504b produced average recoveries (n = 16) ranging from 95% (Li, Zr) to 111% (Ni, Zn) relative to the certified values, with 21 of 23 elements recovering within ±10% of the certified value.
Precision was strong throughout, with %RSD at or below 4.7% for every element.
Copper and gold – the primary analytes of interest for this porphyry copper-gold matrix – recovered at 101% and 97%, respectively, confirming that ColdBlock aqua regia digestion delivers accurate and precise recovery of these elements from this ore type.

Results

ColdBlock recoveries (n = 16) relative to the OREAS 504b certified values are summarized below.

Element	Certified Value (mg/kg)	ColdBlock Average, n=16 (mg/kg)	% Recovery	% RSD
Au	1.61	1.56	97%	3.7%
Al	19300	19100	99%	1.2%
Ba	166	176	106%	1.4%
Ca	16400	17500	107%	3.0%
Co	18.7	20.2	108%	3.6%
Cr	67	71	105%	2.0%
Cu	11000	11000	101%	2.2%
Fe	67100	71000	106%	1.7%
K	5500	5700	103%	3.7%
Li	21.7	20.7	95%	2.1%
Mg	13000	13000	101%	1.6%
Mn	406	445	110%	2.7%
Mo	476	511	107%	3.1%
Na	1830	1830	100%	4.0%
Ni	30	33	111%	2.4%
P	920	900	98%	3.1%
Pb	20.1	21.3	106%	4.6%
S	13100	13000	99%	1.4%
Sr	110	110	102%	1.7%
Ti	2200	2200	101%	1.6%
V	128	140	109%	1.6%
Zn	96	107	111%	4.7%
Zr	14.2	13.4	95%	3.2%

Click here to download the Application Note in PDF format.

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