Lead Concentrate – AMIS 0618 - ColdBlock Technologies

APPLICATION NOTE

Lead Concentrate – AMIS 0618

SUMMARY

The application note summarizes the digestion of AMIS 0618, a lead concentrate certified reference material using ColdBlock Digestion Pro Series Technology.

Instrument:	ColdBlock CBM Pro-Series sample digester, chiller, HF liners, ICP-OES
Published:	March 2025
Digestion Time:	30 Minutes
Acid Used:	HNO3, HCl, HF, & H3BO3
Average ColdBlock Recovery vs. CRM:	100% antimony 96% arsenic 101% lead

METHODOLOGY

Chiller temperature was set to -5°C
0.25g of each sample was weighed and placed into a ColdBlock™ Digestion vessel
20mL of reverse aqua regia + 3mL HF was added
Samples were digested at 80% power for 20 minutes
20mL of 4% boric acid v/v was added
Samples were digested again at 80% power for 10 minutes
Samples were cooled and bulked to 50mL using 2% HNO₃

DISCUSSION

The addition of Boric acid will help re-solubilize any insoluble fluorides and will help neutralize any remaining HF in solution
After digestion, the samples were clear, and no visible sample material remained
To improve silver recoveries, bulk samples in >20% HCl (precipitation of insoluble lead chloride (PbCl₂) might occur)

AMIS 0618 after bulk up in 2% HNO₃

The material for AMIS 0618 was provided by Black Mountain Mining and is a lead concentrate made from Black Mountain Broken Hill type ore from the Northern Cape Province in South Africa www.Amis.co.za

AMIS 0618; Lead Concentrate, Black Mountain, Northern Cape, South Africa; AMIS, Matrix Reference Materials; Gauteng,

South Africa (May 2019)

Results

AMIS 0618, Lead Concentrate
Method:	0.25g – Add 20mL reverse aqua regia (1:3, HCl:HNO₃) + 3mL HF and digest at 80% power for 20 minutes. Add 20mL of 4% boric acid v/v and digest again at 80% power for 10 minutes. Let cool, and bulk to a final volume of 50mL with 2% HNO₃
Element	AMIS Certified 4-Acid Value (mg/kg)	AMIS +/-	ColdBlock Average (mg/kg) n=5	ColdBlock Stdev	ColdBlock % RSD	ColdBlock % Recovery
Antimony	175	38	175	7.42	4.2%	100%
Arsenic	212	24	204	8.72	4.3%	96%
Barium	97	14	102	0.79	0.8%	105%
Bismuth	2863	229	2819	57.56	2.0%	99%
Cadmium	88	8	90	1.60	1.8%	102%
Calcium	939	212	846	9.31	1.1%	90%
Cobalt	228	17	246	2.52	1.0%	108%
Copper	20100	1200	20146	259.09	1.3%	100%
Iron	51900	3200	51344	761.66	1.5%	99%
Lead	698600	8200	702116	10184	1.5%	101%
Magnesium	1193	173	1135	15.82	1.4%	95%
Manganese	6551	388	6209	74.45	1.2%	95%
Molybdenum	221	34	248	4.85	2.0%	112%
Nickel	73	8	83	2.93	3.6%	113%
Silver	592	53	260	54.4	21%	44%
Sulfur*	141600	3500	148154	2633.70	1.8%	105%
Strontium	3	0.8	3	0.03	0.8%	101%
Zinc	19800	610	19895	333.46	1.7%	101%

*Sulfur certified by combustion/leco

Click here to download the Application Note in PDF format.

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