1148 XXXI International Mineral Processing Congress 2024 Proceedings/Washington, DC/Sep 29–Oct 3
as SCMG1) which can treat a feed particle size range of 500
micron to 1 micron was used in this experimental work.
Its structure and operating conditions were given else-
where (MGS Application Guide 1991 Chan et al., 1991).
The feed to the MGS was maintained at 33% solids con-
centration (by weight). The mixture was stirred continu-
ously to maintain uniform suspension. The MGS variables
were adjusted at the required level as per the experimental
design. The feed slurry was then fed to the MGS feed ves-
sel at the required flow rate as the MGS was in operation.
The MGS was kept running until the material flow was fin-
ished, which took about 5 minutes, and MGS was stopped.
After completion of the test, a small amount of wash water
was added to the heavies discharge end of the drum to wash
out entrained low-density particles. Heavy product, which
was collected through front launder, referred to as tail-
ings, and light product, which was collected through back
launder, referred to as concentrate. The main operating
variables of MGS are shake amplitude, shake frequency,
drum rotational speed (RPM), drum angle of inclination,
wash water flow rate (LPM) and feed consistency (percent
solids). In the present study drum rotational speed (RPM),
drum angle of inclination and wash water are selected as
variables. The feed percent solids (33%), shake amplitude
(18 mm) and shake frequency (4cps) were maintained con-
stant throughout the experimentation.
Response Surface Methodology
Response Surface Methodology (RSM) is a collection of
statistical and mathematical methods that are useful for
modelling and analyzing problems is explained by Myers
(2009). In this technique, the main objective is to opti-
mize the response surface that is influenced by various pro-
cess parameters. The RSM also quantifies the relationship
between the controllable input parameters and the response
surfaces.
Testing and Test Results
In the present study, the Box–Behnken factorial design
was used to find out the relationship between the response
functions (grade and recovery of the concentrate) and three
variables of the multi gravity separator (angle of inclina-
tion, wash water and rotational speed). All the experiments
were conducted using a Mozley laboratory C900 MGS
supplied by Richard Mozley, UK. The variables and their
levels considered for the test program are given in Table 3.
The products of each test were collected dried, weighed,
and analyzed for grade and recovery values. The obtained
results were used for the computer simulation programming
Table 2. Screen assay analysis of stage crushed and ground to
0.150 mm sample
Product Size (Micron) Wt% %Fe %SiO2
+152 microns 152 Nil — —
+104 microns 104 8.64 36.30 48.20
+75 microns 75 11.58 36.00 48.00
+66 microns 66 8.88 37.70 45.20
+44 microns 44 17.07 40.50 42.20
+37 microns 37 4.68 41.50 38.48
–37 microns –37 49.15 43.00 36.00
Head (Cal) 100.00 40.64 40.44
Head (Act) 40.80 40.90
0
10
20
30
40
50
60
0 20 40 60 80 100 120
Size in Microns
Distribution of Iron and Silica in stage crushed &ground product
Wt%
%Fe
%SiO2
Figure 2. Distribution of Iron and silica in size fractions of stage crushed and ground –0.150 mm product
Percentage
as SCMG1) which can treat a feed particle size range of 500
micron to 1 micron was used in this experimental work.
Its structure and operating conditions were given else-
where (MGS Application Guide 1991 Chan et al., 1991).
The feed to the MGS was maintained at 33% solids con-
centration (by weight). The mixture was stirred continu-
ously to maintain uniform suspension. The MGS variables
were adjusted at the required level as per the experimental
design. The feed slurry was then fed to the MGS feed ves-
sel at the required flow rate as the MGS was in operation.
The MGS was kept running until the material flow was fin-
ished, which took about 5 minutes, and MGS was stopped.
After completion of the test, a small amount of wash water
was added to the heavies discharge end of the drum to wash
out entrained low-density particles. Heavy product, which
was collected through front launder, referred to as tail-
ings, and light product, which was collected through back
launder, referred to as concentrate. The main operating
variables of MGS are shake amplitude, shake frequency,
drum rotational speed (RPM), drum angle of inclination,
wash water flow rate (LPM) and feed consistency (percent
solids). In the present study drum rotational speed (RPM),
drum angle of inclination and wash water are selected as
variables. The feed percent solids (33%), shake amplitude
(18 mm) and shake frequency (4cps) were maintained con-
stant throughout the experimentation.
Response Surface Methodology
Response Surface Methodology (RSM) is a collection of
statistical and mathematical methods that are useful for
modelling and analyzing problems is explained by Myers
(2009). In this technique, the main objective is to opti-
mize the response surface that is influenced by various pro-
cess parameters. The RSM also quantifies the relationship
between the controllable input parameters and the response
surfaces.
Testing and Test Results
In the present study, the Box–Behnken factorial design
was used to find out the relationship between the response
functions (grade and recovery of the concentrate) and three
variables of the multi gravity separator (angle of inclina-
tion, wash water and rotational speed). All the experiments
were conducted using a Mozley laboratory C900 MGS
supplied by Richard Mozley, UK. The variables and their
levels considered for the test program are given in Table 3.
The products of each test were collected dried, weighed,
and analyzed for grade and recovery values. The obtained
results were used for the computer simulation programming
Table 2. Screen assay analysis of stage crushed and ground to
0.150 mm sample
Product Size (Micron) Wt% %Fe %SiO2
+152 microns 152 Nil — —
+104 microns 104 8.64 36.30 48.20
+75 microns 75 11.58 36.00 48.00
+66 microns 66 8.88 37.70 45.20
+44 microns 44 17.07 40.50 42.20
+37 microns 37 4.68 41.50 38.48
–37 microns –37 49.15 43.00 36.00
Head (Cal) 100.00 40.64 40.44
Head (Act) 40.80 40.90
0
10
20
30
40
50
60
0 20 40 60 80 100 120
Size in Microns
Distribution of Iron and Silica in stage crushed &ground product
Wt%
%Fe
%SiO2
Figure 2. Distribution of Iron and silica in size fractions of stage crushed and ground –0.150 mm product
Percentage