e-scrap sample preparation

V

vmargatho

New Member
#1
Hi all,

I’m working with eletronic scrap analyses and I have sampling problems. The assay replicates are different in more than 30 ppm for gold.

See below how is the sample preparation.

1- Small Shredder
2- Rotary divider
3- Fusion with Iron and sulfur
4- Pulverizer
5- Fire Assay

I believe that the problem are on the first step, I can’t minimize the particle with my shredder. Can someone recommend the ideal equipment to shred this type of sample?

Regards,

Vinicius Margatho
 
fireguy

fireguy

Supermoderator
#2
Hi all,

I’m working with eletronic scrap analyses and I have sampling problems. The assay replicates are different in more than 30 ppm for gold.

See below how is the sample preparation.

1- Small Shredder
2- Rotary divider
3- Fusion with Iron and sulfur
4- Pulverizer
5- Fire Assay

I believe that the problem are on the first step, I can’t minimize the particle with my shredder. Can someone recommend the ideal equipment to shred this type of sample?

Regards,

Vinicius Margatho
Vinicius: Does your scrap contain circuit board, plastic chips, and other non-metallic components? If so, you might try roasting the sample prior to sample preparation to burn off and char the non-metallic. This roasted material should be more friable. You might need to add a second shredding or pulverizing step prior to rotary splitting.
 
M

Mark Wolle

New Member
#3
Hi Vinicius.

We also process electronic scrap.

What is the particle size of the matte after the pulveriser? How much pulverised sample are you using in each fire assay crucible and what flux components are you using?

Mark Wolle
 
V

vmargatho

New Member
#4
Hello Mark,

I use a ring mill to pulverize the sample under 60 mesh.

The assay charge is 3 grams for 130 grams of flux.

The flux composition is:

Litharge: 74,6%
Borax:4,7%
Silicate: 6,8%
Soda Ash: 13,9%

Vinicius Margatho
 
fireguy

fireguy

Supermoderator
#5
Hello Mark,

I use a ring mill to pulverize the sample under 60 mesh.

The assay charge is 3 grams for 130 grams of flux.

The flux composition is:

Litharge: 74,6%
Borax:4,7%
Silicate: 6,8%
Soda Ash: 13,9%

Vinicius Margatho
Please provide a little more detail on your sample.

What is the original sample size (weight)? Are you splitting after shredding? If so, what size sample (weight) are you producing?

You may need to produce several splits after shredding to check reproducibility at that point. Just because you can obtain good accuracy after pulverizing doesn't necessarily mean this represents the original sample correctly.
 
Last edited:
V

vmargatho

New Member
#6
The inicial weight is something around 20 kg. I use a shredder to get a particule with 3cm x 3cm.

I shred again in another shredder to arrive in a 0,5 cm x 0,5 cm.

After I split several times in a rotary sampler divider until get 100 grams of sample.

Then I fuse with 200 grams of iron and sulfur (66% Fe : 34% S)

Next step is pulverize until 60 mesh and fire assay.
 
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