1396 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
The question of whether the HIT products and
–13.2 mm material had similar breakage characteristics
was addressed by comparing the response of 2.0×1.7 mm
fragments for three samples, namely 11202603 (Axb=32),
11202604 (Axb=331), and 11202606 (Axb=96). The HIT
tests were conducted using 5g, 10g and 15g of fragments
in the cup. The size distribution of the products suggest
the fragments in the HIT products were similar to the
–13.2 mm material, within expected variation within each
sample. The energy applied to the bed can be expressed in
kWh/t or J/g, as defined in the JKDWT (Napier-Munn
et al., 1996), assuming the HIT drop hammer falls onto a
solid base:
Esb =2.72 H M /m (1)
where
Esb =specific energy to bed (kWh/t) =9.81 H M /m
(J/g)
H =drop height (m)
M =mass of dropped mass (kg)
M =mass of particles in bed (g)
For example, in the HIT device, the Esb is effectively 0.31
kWh/t for a 10g of sample, 4.51kg drop mass and 25.4cm
drop height.
The sizing of the products from crushing and HIT
testing was completed using 200 mm diameter sieves and
RoTap sieve shaker. As the HIT sample sizes were small,
the sieves were kept clean between tests. Table 5 shows the
expected number of fragments in the HIT cup for 10g
samples greatly exceed the typical numbers of fragments
used in SMC (100) or even standard HIT tests (30). The
shape factor was assumed to be 0.75. Hence the bed test-
ing is likely to be significantly more representative of the
whole sample, avoiding bias that is possible in SMC and
HIT sample selection.
Figure 6. Workflow in reducing the HIT products to 100% –3.35 mm
Table 4. Mass Distributions from Sample 11202601
(Vesiculated Basalt)
Size Fraction
HIT
Products
–13.2 mm
Material
Sufficient
Mass?
2.0×1.7 mm 65.8g 178.8g Yes (30g)
1.7×1.4 mm 38.6g 89.1g Yes (30g)
1.4×1.18 mm 24.3g 52.6g No (30g)
1.18×1.0 mm 21.8g 65.0g No (30g)
The question of whether the HIT products and
–13.2 mm material had similar breakage characteristics
was addressed by comparing the response of 2.0×1.7 mm
fragments for three samples, namely 11202603 (Axb=32),
11202604 (Axb=331), and 11202606 (Axb=96). The HIT
tests were conducted using 5g, 10g and 15g of fragments
in the cup. The size distribution of the products suggest
the fragments in the HIT products were similar to the
–13.2 mm material, within expected variation within each
sample. The energy applied to the bed can be expressed in
kWh/t or J/g, as defined in the JKDWT (Napier-Munn
et al., 1996), assuming the HIT drop hammer falls onto a
solid base:
Esb =2.72 H M /m (1)
where
Esb =specific energy to bed (kWh/t) =9.81 H M /m
(J/g)
H =drop height (m)
M =mass of dropped mass (kg)
M =mass of particles in bed (g)
For example, in the HIT device, the Esb is effectively 0.31
kWh/t for a 10g of sample, 4.51kg drop mass and 25.4cm
drop height.
The sizing of the products from crushing and HIT
testing was completed using 200 mm diameter sieves and
RoTap sieve shaker. As the HIT sample sizes were small,
the sieves were kept clean between tests. Table 5 shows the
expected number of fragments in the HIT cup for 10g
samples greatly exceed the typical numbers of fragments
used in SMC (100) or even standard HIT tests (30). The
shape factor was assumed to be 0.75. Hence the bed test-
ing is likely to be significantly more representative of the
whole sample, avoiding bias that is possible in SMC and
HIT sample selection.
Figure 6. Workflow in reducing the HIT products to 100% –3.35 mm
Table 4. Mass Distributions from Sample 11202601
(Vesiculated Basalt)
Size Fraction
HIT
Products
–13.2 mm
Material
Sufficient
Mass?
2.0×1.7 mm 65.8g 178.8g Yes (30g)
1.7×1.4 mm 38.6g 89.1g Yes (30g)
1.4×1.18 mm 24.3g 52.6g No (30g)
1.18×1.0 mm 21.8g 65.0g No (30g)