3
Therefore, the primary objective of this study was to
determine the maximum ultrafine tailings percentage in the
mixture among the tested compositions (5% to 15% ultra-
fine tailings) using vacuum disc filter technology for the
dewatering of tailings mixtures intended for dry
stacking. For this purpose, tests were conducted using
the filtration aid CLARIANT FLOTICOR FA 17416.
To test the mixtures on an industrial scale, modifica-
tions were made to the plant’s industrial circuit. As observed
in Figure 3, part of the underflow from the ultrafine tailings
thickener was directed, in a controlled manner, to the filtra-
tion feed tank. This control was achieved using a densim-
eter, flowmeter, and control valve, allowing for the addition
of 5% to 1% of ultrafine tailings mass into the mixture fed
into the filtration plant.
As seen in Figure 4, Clariant and Samarco set up a dos-
ing plant for the filter aid to be pumped to the two slurry
distributors that feed the six vacuum disc filters in this
plant.
Additionally, experimental fills were constructed with
the filtered mixtures to evaluate the conditions for traffic-
ability, workability, and compaction, as well as to assess the
potential effects of adding filtration aids on the handling,
spreading, and compaction processes.
METHODOLOGY
Mineral Samples
Samples were collected hourly from the filters in opera-
tion to determine moisture content. The samples collected
each hour were combined at the end of each test to form
a composite sample representing the test feed, which was
later analysed for particle size distribution and chemical
composition.
Plant Trials Program
Each industrial test was conducted over a period of 6 to 26
hours. The initial tests were performed during the sched-
uled maintenance shutdown of one of the two beneficiation
plant production lines (monthly maintenance shutdown),
effectively reducing the feed mass to the filtration plant by
half. This approach was taken to minimize the risk of a fil-
tration plant shutdown and, consequently, a beneficiation
plant shutdown due to a significant drop in filtration pro-
ductivity, as the plant’s performance with ultrafine tailings
mixtures was initially unknown.
Subsequent tests were conducted with the beneficia-
tion plant operating at nominal capacity, except for tests
with a 10% ultrafine tailings content in the mixture, where
the unit filtration rate was reduced by half. Therefore, tests
with 10% ultrafine tailings were only conducted during the
scheduled shutdown of one of the beneficiation plant’s pro-
duction lines.
In all tests, Floticor FA 17416 filtration aid was dosed
and pumped to the distributors feeding the six vacuum disc
filters. The ultrafine tailings content in the mixture was
controlled continuously at the filtration tank feed.
The filtered mixture from the tests was directed to a
designated area for constructing experimental fills (test
pads) to evaluate geotechnical parameters.
RESULTS AND DISCUSSION
The Table 1 summarizes the main results obtained during
the industrial filtration tests using the filtration aid. The
result with 5% ultrafine tailings in the mixture dosing the
filtration aid was very similar to those already achieved
industrially with sandy tailings alone. It was observed that,
once an optimal filtration aid dosage was established, higher
dosages did not lead to an increase in the unit filtration rate
(UFR) or a reduction in moisture content. For 10% ultra-
fine tailings, productivity was reduced by half, likely due to
the increased fraction of particles below 10 micrometers,
necessitating an increase in the number of filters in opera-
tion to achieve the targeted material mass.
Based on the results obtained and considering
the six existing filters (or a total of 10 filters with the
Figure 3. Plant modifications for industrial tests
Figure 4. Clariant equipment setup for plant trials
Therefore, the primary objective of this study was to
determine the maximum ultrafine tailings percentage in the
mixture among the tested compositions (5% to 15% ultra-
fine tailings) using vacuum disc filter technology for the
dewatering of tailings mixtures intended for dry
stacking. For this purpose, tests were conducted using
the filtration aid CLARIANT FLOTICOR FA 17416.
To test the mixtures on an industrial scale, modifica-
tions were made to the plant’s industrial circuit. As observed
in Figure 3, part of the underflow from the ultrafine tailings
thickener was directed, in a controlled manner, to the filtra-
tion feed tank. This control was achieved using a densim-
eter, flowmeter, and control valve, allowing for the addition
of 5% to 1% of ultrafine tailings mass into the mixture fed
into the filtration plant.
As seen in Figure 4, Clariant and Samarco set up a dos-
ing plant for the filter aid to be pumped to the two slurry
distributors that feed the six vacuum disc filters in this
plant.
Additionally, experimental fills were constructed with
the filtered mixtures to evaluate the conditions for traffic-
ability, workability, and compaction, as well as to assess the
potential effects of adding filtration aids on the handling,
spreading, and compaction processes.
METHODOLOGY
Mineral Samples
Samples were collected hourly from the filters in opera-
tion to determine moisture content. The samples collected
each hour were combined at the end of each test to form
a composite sample representing the test feed, which was
later analysed for particle size distribution and chemical
composition.
Plant Trials Program
Each industrial test was conducted over a period of 6 to 26
hours. The initial tests were performed during the sched-
uled maintenance shutdown of one of the two beneficiation
plant production lines (monthly maintenance shutdown),
effectively reducing the feed mass to the filtration plant by
half. This approach was taken to minimize the risk of a fil-
tration plant shutdown and, consequently, a beneficiation
plant shutdown due to a significant drop in filtration pro-
ductivity, as the plant’s performance with ultrafine tailings
mixtures was initially unknown.
Subsequent tests were conducted with the beneficia-
tion plant operating at nominal capacity, except for tests
with a 10% ultrafine tailings content in the mixture, where
the unit filtration rate was reduced by half. Therefore, tests
with 10% ultrafine tailings were only conducted during the
scheduled shutdown of one of the beneficiation plant’s pro-
duction lines.
In all tests, Floticor FA 17416 filtration aid was dosed
and pumped to the distributors feeding the six vacuum disc
filters. The ultrafine tailings content in the mixture was
controlled continuously at the filtration tank feed.
The filtered mixture from the tests was directed to a
designated area for constructing experimental fills (test
pads) to evaluate geotechnical parameters.
RESULTS AND DISCUSSION
The Table 1 summarizes the main results obtained during
the industrial filtration tests using the filtration aid. The
result with 5% ultrafine tailings in the mixture dosing the
filtration aid was very similar to those already achieved
industrially with sandy tailings alone. It was observed that,
once an optimal filtration aid dosage was established, higher
dosages did not lead to an increase in the unit filtration rate
(UFR) or a reduction in moisture content. For 10% ultra-
fine tailings, productivity was reduced by half, likely due to
the increased fraction of particles below 10 micrometers,
necessitating an increase in the number of filters in opera-
tion to achieve the targeted material mass.
Based on the results obtained and considering
the six existing filters (or a total of 10 filters with the
Figure 3. Plant modifications for industrial tests
Figure 4. Clariant equipment setup for plant trials