2056 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
Feed Rate
The test of Vwas conducted under the conditions of f 35
Hz, P 0.03 Mpa, and the test results are shown in Figure 11.
With the increase of V, the clean coal ash increases gradu-
ally from 3.13 to 4.72%, and the clean coal yield increases
firstly and then decreases, and reaches the maximum in
the feed rate of 35 ml/s. The vitrinite content in the clean
coal shows a decreasing trend with the increase of V, from
62.45 to 55.87%. When V increases, the thickness of the
bed in the sorting area gradually increases, the low-density
particles move from the inside of the bed to the overflow,
which will drive a small part of the intermediate-density
level particles that are in the balance of force to become
the overflow.This causes the clean coal yield to increase, as
well as the ash content, intermediate density level particles
containing more vitrinite to become overflow causes the
vitrinitecontent to decrease and the inertinitecontent to
increase. When V is too large, the bed is too thick, and it is
more difficult for the low-density particles to penetrate the
bed to become overflow, resulting in the deterioration of
sorting effect.
With the increase of V, the enrichment ratio is decreas-
ing from 1.10 to 0.99, andthe recovery rate decreases
from 72.01 to 62.54%. The enrichment ratio is related to
the vitrinite content in the clean coal product. With the
increase of feed rate, the thickness of bed layer in sorting
area increases gradually, and when the low-density par-
ticles penetrate the bed layer and become overflow.It will
drive the intermediate-density particles containing more
inertinite to become the overflow product, resulting in the
decrease of vitrinite content in the refined coal products,
which leads to the decrease of the enrichment ratio and
recovery rate of vitrinite.
Orthogonal Test
The effect of enhanced gravity separation of macerals were
explored when the three factors of rotational frequency f,
backwash water pressure P and feed rate V were varied indi-
vidually. In order to analyze the effect of the interaction
between the factors on the experimental results, an orthog-
onal test was designed with the test invariants: 10% slurry
concentration, 100 g feed volume, and the other param-
eters as shown in Table 6, and the test results are shown in
Table 7.Through the orthogonal test, the optimal vitrinite
recovery of 72.56% and optimal enrichment ratio of 1.33
could be obtained respectively.
The ANOVA of the recommended quadratic model for
RV and EV were conducted. For the RV, there is an interac-
tion between f and P, and the effect of f on RV is greater
than that of P. According to the parameter estimation,the
model equation for RV and EV were established:
..98
..17B
R A
AB
71 08 4 1.97B
2 23 3.85A 1
V
2 2
=-+
+--
(3)
...025C
..049A
E A B
AC
1 09 0.11 0 084 0
0 035 0
V
2
=+--
++
(4)
where RV is the vitrinite recovery, EV is the enrichment
ratio, A is the rotational frequency, B is the backwash water
pressure, C is the feed rate.
Figure 12 show the response surfaces of RV and EVunder
the action of different combinations of two parameters.As
can be seen from Figure 12a, RV shows a decreasing trend
Figure 10. Variation of sorting and evaluation indicators with backwash water pressure
Feed Rate
The test of Vwas conducted under the conditions of f 35
Hz, P 0.03 Mpa, and the test results are shown in Figure 11.
With the increase of V, the clean coal ash increases gradu-
ally from 3.13 to 4.72%, and the clean coal yield increases
firstly and then decreases, and reaches the maximum in
the feed rate of 35 ml/s. The vitrinite content in the clean
coal shows a decreasing trend with the increase of V, from
62.45 to 55.87%. When V increases, the thickness of the
bed in the sorting area gradually increases, the low-density
particles move from the inside of the bed to the overflow,
which will drive a small part of the intermediate-density
level particles that are in the balance of force to become
the overflow.This causes the clean coal yield to increase, as
well as the ash content, intermediate density level particles
containing more vitrinite to become overflow causes the
vitrinitecontent to decrease and the inertinitecontent to
increase. When V is too large, the bed is too thick, and it is
more difficult for the low-density particles to penetrate the
bed to become overflow, resulting in the deterioration of
sorting effect.
With the increase of V, the enrichment ratio is decreas-
ing from 1.10 to 0.99, andthe recovery rate decreases
from 72.01 to 62.54%. The enrichment ratio is related to
the vitrinite content in the clean coal product. With the
increase of feed rate, the thickness of bed layer in sorting
area increases gradually, and when the low-density par-
ticles penetrate the bed layer and become overflow.It will
drive the intermediate-density particles containing more
inertinite to become the overflow product, resulting in the
decrease of vitrinite content in the refined coal products,
which leads to the decrease of the enrichment ratio and
recovery rate of vitrinite.
Orthogonal Test
The effect of enhanced gravity separation of macerals were
explored when the three factors of rotational frequency f,
backwash water pressure P and feed rate V were varied indi-
vidually. In order to analyze the effect of the interaction
between the factors on the experimental results, an orthog-
onal test was designed with the test invariants: 10% slurry
concentration, 100 g feed volume, and the other param-
eters as shown in Table 6, and the test results are shown in
Table 7.Through the orthogonal test, the optimal vitrinite
recovery of 72.56% and optimal enrichment ratio of 1.33
could be obtained respectively.
The ANOVA of the recommended quadratic model for
RV and EV were conducted. For the RV, there is an interac-
tion between f and P, and the effect of f on RV is greater
than that of P. According to the parameter estimation,the
model equation for RV and EV were established:
..98
..17B
R A
AB
71 08 4 1.97B
2 23 3.85A 1
V
2 2
=-+
+--
(3)
...025C
..049A
E A B
AC
1 09 0.11 0 084 0
0 035 0
V
2
=+--
++
(4)
where RV is the vitrinite recovery, EV is the enrichment
ratio, A is the rotational frequency, B is the backwash water
pressure, C is the feed rate.
Figure 12 show the response surfaces of RV and EVunder
the action of different combinations of two parameters.As
can be seen from Figure 12a, RV shows a decreasing trend
Figure 10. Variation of sorting and evaluation indicators with backwash water pressure