4
It should be noted that Walker tests for the quartz
samples were conducted without the addition of surfac-
tants (30). As shown in Table 4 and expectedly, the lon-
gest settling times were in deionized water (the absence of
ions) giving the full LVb is low volatile bituminous, MVb
is medium volatile bituminous, and HVAb is high volatile
A bituminous coal ranks effect of the surface charge of the
particles. In process water and simulated lung fluid, the set-
tling times decreased for the bare surfaces as the surface
Figure 2. Dust Settling Rate Test (Walker Test)
Table 3. Effect of Surfactants on Surface OH Content for Various Quartz Samples Collected from Coal of
Various Ranks at pH 7 (30)
Coal Quartz →
Surfactant
OH (10–9 mol.L–1) at pH 7
Anthracite Quartz LVb Quartz MVb Quartz HVAb Quartz
Bare Surface 65 75 97 89
1 Dosage 1 63 14 7 9
Dosage 2 59 12 6 7
2 Dosage 1 24 60 14 12
Dosage 2 15 55 13 11
3 Dosage 1 11 21 8 12
Dosage 2 9 15 7 11
4 Dosage 1 10 20 8 8
Dosage 2 9 14 7 8
5 Dosage 1 8 31 8 10
Dosage 2 6 15 8 9
6 Dosage 1 8 10 9 8
Dosage 2 8 9 7 8
7 Dosage 1 13 14 8 7
Dosage 2 10 13 7 6
8 Dosage 1 12 17 42 47
Dosage 2 12 16 41 44
9 Dosage 1 6 7 7 10
Dosage 2 6 6 7 7
LVb is low volatile bituminous, MVb is medium volatile bituminous, and HVAb is high volatile A
bituminous coal ranks
Table 4. Walker Tests for Bare Quartz with Different Water
Quality (30)
Sample
Time (s)
Deionized
Water
Process
Water
Sim. Lung
Fluid
Anthracite Quartz 126 64 35
LVb Quartz 226 84 55
MVb Quartz 219 92 64
HVAb Quartz 229 96 83
It should be noted that Walker tests for the quartz
samples were conducted without the addition of surfac-
tants (30). As shown in Table 4 and expectedly, the lon-
gest settling times were in deionized water (the absence of
ions) giving the full LVb is low volatile bituminous, MVb
is medium volatile bituminous, and HVAb is high volatile
A bituminous coal ranks effect of the surface charge of the
particles. In process water and simulated lung fluid, the set-
tling times decreased for the bare surfaces as the surface
Figure 2. Dust Settling Rate Test (Walker Test)
Table 3. Effect of Surfactants on Surface OH Content for Various Quartz Samples Collected from Coal of
Various Ranks at pH 7 (30)
Coal Quartz →
Surfactant
OH (10–9 mol.L–1) at pH 7
Anthracite Quartz LVb Quartz MVb Quartz HVAb Quartz
Bare Surface 65 75 97 89
1 Dosage 1 63 14 7 9
Dosage 2 59 12 6 7
2 Dosage 1 24 60 14 12
Dosage 2 15 55 13 11
3 Dosage 1 11 21 8 12
Dosage 2 9 15 7 11
4 Dosage 1 10 20 8 8
Dosage 2 9 14 7 8
5 Dosage 1 8 31 8 10
Dosage 2 6 15 8 9
6 Dosage 1 8 10 9 8
Dosage 2 8 9 7 8
7 Dosage 1 13 14 8 7
Dosage 2 10 13 7 6
8 Dosage 1 12 17 42 47
Dosage 2 12 16 41 44
9 Dosage 1 6 7 7 10
Dosage 2 6 6 7 7
LVb is low volatile bituminous, MVb is medium volatile bituminous, and HVAb is high volatile A
bituminous coal ranks
Table 4. Walker Tests for Bare Quartz with Different Water
Quality (30)
Sample
Time (s)
Deionized
Water
Process
Water
Sim. Lung
Fluid
Anthracite Quartz 126 64 35
LVb Quartz 226 84 55
MVb Quartz 219 92 64
HVAb Quartz 229 96 83