This document outlines the procedure for pre-attritioning activated carbon in order to remove fines and sharp edges that could interfere with metallurgical testing. The procedure involves vigorously mixing the carbon slurry for 24 hours to weaken carbon particles, followed by wet and dry screening to separate out the fines. The goal is to reduce the amount of fines in subsequent metallurgical tests that may affect results. Safety equipment like glasses and masks are required, along with equipment for mixing, screening, drying, and storing the prepared carbon samples.

1. Minerals Services Revision
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Minerals Services
Gold Project Scoping Phase
Carbon Attrition and
Preparation
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1.0 SCOPE
To pre-attrition activated carbon in order to remove fines and sharp edges that will interfere with
metallurgical testing.
2.0 SAFETY
Safety glasses
Dust mask
Forced air ventilation
3.0 EQUIPMENT & REAGENTS
20 L pails
DI water
Variable speed mixer and 15 cm turbine impeller
16 Tyler mesh screen (1000 microns)
1600 mL silica cleaning sand (less than 500 micron)
Vibrator and sieve ring holder for wet screening
Ro-tap for dry screening
Drying oven at 110°C
Drying pans
4.0 SAMPLE REQUIREMENT
10 L of new (unused) activated carbon (Calgon GRC 22)
5.0 OVERVIEW
Pre-attritioning activated carbon is accomplished by subjecting the slurried carbon to vigorous mixing.
Weak carbon particles (that would otherwise breakdown in a leach or adsorption test) are thereby
eliminated. This reduces the amount of fines in subsequent metallurgical tests, which are likely to
affect results.
6.0 PROCEDURE
Activated carbon depletes oxygen from
surrounding air. Work in a well-ventilated area if
opening a large container of carbon or working
around a large pile of carbon.
1. Obtain ~10 L sample of carbon to be attritioned. Place in a 20-L pail.
2. Add deionized (DI) water to ¾ fill level.
3. Insert mixer impeller in pail. Turn on mixer. Apply vigorous agitation by increasing the
speed of the agitator until a vortex develops without splashing.
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Ensure that the impellor is 2 inches off the bottom of the pail
so that the carbon does not get crushed.
4. Add 1600 mL of fine cleaning sand (silica) with a particle size small enough to pass
through screening later (less than 500 microns).
Add cleaning sand at a carbon to cleaning sand ratio of
about 20:1 by weight.
5. Agitate vigorously for ~24 hours (usually overnight).
6. Wet screen the carbon on a 16 mesh vibrating screen, in small batches, washing each
batch very well. Discard wash water and resultant carbon-sand fines.
7. Retain the screen oversize (carbon) fraction. Place in drying pans and dry at 110°C to
constant weight.
Spread out carbon in even layers not greater than ½ inch to
ensure even and efficient drying.
8. Dry screen the carbon on a 16 mesh vibrating screen. Retain the plus material and
discard the fines.
9. Place in a container (for future testing) with a lid that allows a tight seal when closed.
Make sure the container is properly labeled. Carbon absorbs moisture from air – keep
container sealed when not in use.
A simple check to see if carbon has been attritioned properly
– swirl a latex-gloved hand within the bed of dry carbon. If
the carbon has been properly attritioned, there will be almost
no carbon fines adhering to the latex glove.
7.0 CALCULATIONS
N/A
8.0 REPORTING
N/A
9.0 REFERENCES
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3. Minerals Services Revision
General Doc Type
Global
Method No:
Service
Minerals Services
Gold Project Scoping Phase
Carbon Attrition and
Preparation
Issued Date
Review Date
Approved by
N/A
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