5
Figure 7 and Figure 8 display the microscopic obser-
vations of froth without wash water and with wash water.
In Figure 7, entrained black and red iron oxides gangue
minerals were reduced by using wash water in Figure 8,
the entrainment of silica gangue minerals was effectively
reduced by wash water.
Three-Factor Three-Level Central Composite Design
Table 3. is offered to summarize the three-factor three-
level central composite design experiment flotation results.
Response surface methodology was used to analyze the
three-factor (wash water rate, feed slurry solids content,
and feed particle size) three-level central composite ultra-
fine phosphate column flotation experiment data. Response
surface, cubic graph and contours were generated for the
floated concentrate P2O5 grade and the floated concentrate
P2O5 recovery as a function of three process parameters
included wash water flow rate, feed slurry solids content,
and feed particle size (P80).
Figure 9 illustrates the effects of wash water flow rate
and feed particle size (P80) on the floated concentrate P2O5
grade. As shown in Figure 9, the middle level particle size
(P80=38 microns) feed floated concentrate P2O5 grade
significantly increases from approximately 16% P2O5 to
around 24% P2O5 and 30% P2O5 as the wash water flow
20 µm
Ultrafine iron oxides(red/black) particles entrained to phosphate product
Figure 5. Microscopic observations of ultrafine iron oxide
particles entrained to froth product during benchtop
mechanical cell flotation
Wash water rate:
0 Liter/Minute
Wash water rate:
400 Liter/Minute
Wash water rate:
800 Liter/Minute
Wash water tube Interface between collection zone and froth zone
Feed
Feed Feed
Figure 6. Column froth with various wash water rate
50 µm
Ultrafine particles attached to ultrafine/fine bubbles
With wash water
Without wash water
Figure 7. Microscopic observations of froth without
wash water and with wash water. Entrained black
and red iron oxides reduced by wash water
Figure 7 and Figure 8 display the microscopic obser-
vations of froth without wash water and with wash water.
In Figure 7, entrained black and red iron oxides gangue
minerals were reduced by using wash water in Figure 8,
the entrainment of silica gangue minerals was effectively
reduced by wash water.
Three-Factor Three-Level Central Composite Design
Table 3. is offered to summarize the three-factor three-
level central composite design experiment flotation results.
Response surface methodology was used to analyze the
three-factor (wash water rate, feed slurry solids content,
and feed particle size) three-level central composite ultra-
fine phosphate column flotation experiment data. Response
surface, cubic graph and contours were generated for the
floated concentrate P2O5 grade and the floated concentrate
P2O5 recovery as a function of three process parameters
included wash water flow rate, feed slurry solids content,
and feed particle size (P80).
Figure 9 illustrates the effects of wash water flow rate
and feed particle size (P80) on the floated concentrate P2O5
grade. As shown in Figure 9, the middle level particle size
(P80=38 microns) feed floated concentrate P2O5 grade
significantly increases from approximately 16% P2O5 to
around 24% P2O5 and 30% P2O5 as the wash water flow
20 µm
Ultrafine iron oxides(red/black) particles entrained to phosphate product
Figure 5. Microscopic observations of ultrafine iron oxide
particles entrained to froth product during benchtop
mechanical cell flotation
Wash water rate:
0 Liter/Minute
Wash water rate:
400 Liter/Minute
Wash water rate:
800 Liter/Minute
Wash water tube Interface between collection zone and froth zone
Feed
Feed Feed
Figure 6. Column froth with various wash water rate
50 µm
Ultrafine particles attached to ultrafine/fine bubbles
With wash water
Without wash water
Figure 7. Microscopic observations of froth without
wash water and with wash water. Entrained black
and red iron oxides reduced by wash water