# Patent

## Title
Depressor in iron ore flotation comprising sugar cane bagasse, use of sugar cane bagasse as depressor in iron ore flotation and process of preparing depressor comprising sugar cane bagasse

## Abstract

A depressor in iron ore flotation comprises sugar cane bagasse and caustic soda so as to assist in the iron ore flotation.
Sugar cane bagasse is used as a depressor in iron ore flotation, and a process of preparing depressor comprising sugar cane bagasse is disclosed.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is based upon and claims benefit of priority of the U.S. Patent Application No. 61/696,710, filed Sep. 4, 2012, the disclosure of the prior application is hereby incorporated in its entirety by reference.


STATE OF THE ART
The concentration of minerals occurs when it is necessary to separate the minerals or metals of interest from those which are not. For this separation to occur, the minerals of interest cannot be physically aggregated to those which are not of interest. In such case, it is necessary to perform stages of fragmentation and classification so as to achieve this separation.
To perform the separation of minerals, there must be a physical or physical-chemical difference between the metal of interest and the other components in the mineral and it may be easy or highly complex, depending on the mineral. The most used physical properties in separating or concentrating minerals or metals are the difference in density or difference in magnetic susceptibility. In contrast, when there is no difference in minimal physical property between the minerals or metals that need to be separated, techniques are used based on the physical-chemical properties of the surface of the materials. The most widely used technique in this case is flotation. It is a highly versatile and selective process. It allows concentrates to be obtained that have high contents and significant recoveries. It is usually applied in the processing of minerals with low content and fine granulometry generally in an aqueous suspension. Furthermore, it is possible to use specific reagents, such as collectors, depressors and modifiers, which assist in the selective recovery of the minerals or metals of interest.
Starch is known to be used to assist in iron ore flotation in order to achieve lower iron contents in flotation reject of this mineral.
The present invention discloses a novel depressor to assist the flotation of the iron ore in order to obtain lower iron contents in the reject of said flotation.



DETAILED DESCRIPTION OF THE DRAWINGS
FIG. 1—evolution of the tests with greater depressor dosage.



DETAILED DESCRIPTION OF THE INVENTION
The present invention refers to a novel depressor to assist in the flotation of iron ore so as to obtain iron contents in the reject of said flotation in accordance with current standards.
More specifically, it refers to the use of sugar cane bagasse as depressor in iron ore flotation.
It further refers to a process of preparing depressor in iron ore flotation that comprises sugar cane bagasse and caustic soda.
Demonstrated below are preferred embodiments of a process of preparing depressor comprising sugar cane bagasse.
The process of preparing a depressor comprising treated sugar cane bagasse comprises the following stages:

    
    
        a. mixing sugar cane bagasse with water, obtaining a first mixture;
        b. adding caustic soda to the mixture above at a ratio of 6:1 to 10:1 part of bagasse: caustic soda, obtaining a second mixture;
        c. letting it stand;
        d. adding additional water, and
        e. agitating
    
    


The feed samples of the flotation (mineral) were filtered, homogenized and quartered, separating amounts of 1800 g for each test.
In a first preferred embodiment of the invention, the process of preparing a depressor comprising treated sugar cane bagasse comprises the following stages:

    
    
        a. mixing 10 grams of the treated sugar cane bagasse with 250 ml of water, obtaining a first mixture;
        b. after 5 minutes, adding caustic soda to the mixture above at a ratio of 8:1 part of bagasse: caustic soda, obtaining a second mixture;
        c. letting it stand for a further 30 minutes;
        d. adding water until reaching 1000 ml, and
        e. agitating for a further 10 minutes in an agitator, obtaining the depressor.
    
    


The total time for carrying out the process of preparing depressor comprising sugar cane bagasse is similar to the time for preparing an iron ore depressor comprising corn starch.
The depressor comprising sugar cane bagasse was conditioned for 3 minutes and amine (amine solution at 1%) for 1 minute.
The flotation of the iron ore using a depressor comprising sugar cane bagasse was carried out, and the reject was collected from 2 minutes to 2 minutes and 30 seconds.
The tests were carried out according to workbench test standards (flotation until exhaustion). The parameters used for the flotation tests are shown in table 1.







TABLE 1







parameters used in the tests.













Test
1
2
3
4







pH
10.8
10.0
10
10.05



Depressor/
500 g/t
700 g/t
900 g/t
1100 g/t



bagasse



Amine
180 g/t
180 g/t
180 g/t
 180 g/t




Sio2
Sio2
Sio2
Sio2










Chemical results and flotation performance are shown in table 2 below.







TABLE 2





Chemical results.





















IDENTIFICATION
Fe
SiO2
P
Al2O3
Mn
TiO2

















Tests 01 - 500 g/t
Concentrate
66.710
1.720
0.043
0.300
0.156
0.049



Reject
13.890
78.280
0.013
0.490
0.046
0.001


Tests 01 - 700 g/t
Concentrate
67.020
1.740
0.049
0.340
0.181
0.047



Reject
21.550
67.840
0.010
0.400
0.016
0.001


Tests 01 - 900 g/t
Concentrate
67.050
1.250
0.047
0.310
0.172
0.047



Reject
18.500
72.010
0.008
0.450
0.015
0.001


Tests 01 - 1100 g/t
Concentrate
66.670
1.910
0.045
0.340
0.161
0.039



Reject
18.310
71.840
0.014
0.470
0.053
0.019















IDENTIFICATION
CaO
MgO
PPC

















Tests 01 - 500 g/t
Concentrate
0.011
0.018
1.70




Reject
0.009
0.015
0.57



Tests 01 - 700 g/t
Concentrate
0.013
0.035
1.96




Reject
0.006
0.043
0.30



Tests 01 - 900 g/t
Concentrate
0.014
0.001
1.89




Reject
0.006
0.005
0.36



Tests 01 - 1100 g/t
Concentrate
0.011
0.071
1.76




Reject
0.007
0.041
0.56

















TABLE 3







Flotation performance.











Complementary information
Test 1
Test 2
Test 3
Test 4





Mass recovery
67.13
61.14
63.54
64.19


Metal recovery
90.75
83.03
86.33
86.71


Gaudin selectivity index
14.78
11.01
14.45
11.70









Analyzing the results shown in the tables above, the following is concluded:

    
    
        with the cane bagasse, there was a delay in the discharge of the reject;
        the pH used in test 1 (pH 9.5 to 11.0) showed better results of Fe content in the reject (13.89%).
    
    


In a second preferred embodiment of the invention, the process of preparing a depressor comprising sugar cane bagasse treated comprises the following stages:

    
    
        a. mixing 10 grams of the sugar cane bagasse treated with 250 ml of water, obtaining a first mixture;
        b. after 5 minutes, adding caustic soda to the mixture above in a ratio of 8:1 part of bagasse: caustic soda, obtaining a second mixture;
        c. letting it stand for a further 30 minutes;
        d. adding water until reaching 1000 ml, and
        e. agitating for a further 10 minutes in a mechanical agitator.
    
    


The product of this process is the depressor comprising sugar cane bagasse.
The total time for carrying out the process of preparing depressor comprising sugar cane bagasse is similar to the time for preparing an iron ore depressor comprising corn starch.
Preferably, the preparation of depressor (corn starch or BMC) together with NaOH may comprise the following additional stages:

    
    
        i. Determining the humidity of the first mixture (sugar cane bagasse) before beginning the first mixture;
        ii. Measuring the mass (30 to 40 g) of the material and annotating its value;
        iii. Placing the material to dry in a hothouse at a temperature of 105° C. for about 2 hours;
        iv. Withdrawing the material from the hothouse,
        v. Letting it cool for about 10 minutes,
        vi. Measuring the mass of the material stage v;
        vii. Annotating the value of the mass after drying and calculating the humidity as follows:
    
    






  UD
  =
  
    
      (
      
        1
        -
        
          PS
          PU
        
      
      )
    
    ×
    100
  




Wherein:

    UD=humidity of the material−sugar cane bagasse (%)
    PS=dry weight of the material−sugar cane bagasse (g)
    PU=wet weight of the material−sugar cane bagasse (g)
    
        viii. Calculating the masses: material−sugar cane bagasse and sodium hydroxide using the formulae set forth below:
    
    





  
    
      M
      3
    
    =
    
      
        
          C
          3
        
        ×
        
          M
          4
        
      
      100
    
  




  
    
      M
      5
    
    =
    
      
        
          M
          3
        
        
          100
          -
          U
        
      
      ×
      100
    
  




  
    
      M
      6
    
    =
    
      
        
          M
          3
        
        Y
      
      ×
      2
    
  



Wherein:

    M3=dry mass of the material−sugar cane bagasse (g)
    C3=desired concentration of the depressor solution (%)
    M4=desired mass of the depressor solution (g)
    M5=wet mass of the material−sugar cane bagasse (g)
    U=humidity of the material−sugar cane bagasse (%)
    M6=mass of caustic soda at 50% (g)
    Y=numerator of the ratio sugar cane bagasse/caustic soda
    
        ix. Calculating the masses: gelatinization water and dilution:

M7=(M4×0.1)−M5−M6 

M8=M4−M5−M6−M7 

Wherein:

    
    
    M7=mass of water for gelatinization at 10% (g)
    Mg=mass of water for dilution of the solution to the desired concentration (g)
    
        x. Positioning a recipient next to the agitator. If hot water is needed, use the agitator with heater;
        xi. Adding gelatinization water (M7) into the recipient and agitate;
        xii. Slowing adding the first mixture (M5) into the preparation recipient and wait for about 10 minutes;
        xiii. Slowing adding the solution of caustic soda (M6);
        xiv. Adjusting the rotation of the agitator so as to maintain the solution homogeneous during gelatinization;
        xv. Waiting for about 20 minutes for full gelatinization of the second mixture;
        xvi. Adding into the recipient the dilution water (M8) and waiting for about 10 minutes. If the recipient cannot accommodate all the mass, transfer the second mixture to a second recipient with greater capacity;
        xvii. Switch off the agitator after 10 minutes;
        xviii. Make the second prepared mixture available for use, protecting it from contaminations;
        xix. After preparing the second mixture, check its concentration using a refractometer.
    
    


The flotation of the iron ore using a depressor comprising sugar cane bagasse was carried out, and the reject collected from 2 minutes to 2 minutes and 30 seconds.
The tests were carried out according to workbench test standards (flotation until exhaustion). The parameters used for the flotation tests are shown in table 1.
The parameters used for the flotation tests are shown in table 4.


















Amine
Ratio






Depressor
EDA-C
Starch/Caustic
pH
pH
Time of


Test
(g/t)
(g/t SiO2)
Soda
Test
Final
Test(s)





















01
Gritz - 650
190
 8:1
9.5
8.6
180


02
Gritz - 650
190
 8:1
9.5
8.5
130


03
BMC - 650
190
 8:1
10.0
8.8
210


04
BMC - 450
190
 8:1
9.5
8.0
120


05
BMC - 450
190
 8:1
10.0
8.7
250


06
BMC - 450
190
 8:1
10.5
9.7
210


07
BMC - 650
190
 8:1
9.5
7.9
150


08
BMC - 650
190
 8:1
10.0
8.9
220


09
BMC - 650
190
 8:1
10.5
9.5
160


10
BMC - 1200
190
10:1
10.5
9.3
85


11
BMC - 2400
190
10:1
10.5
9.9
90


12
BMC - 1200
90
10:1
10.5

120


13
BMC - 2400
90
10:1
10.5
10.2
90


14
BMC - 1200
90
10:1
10.5
9.8
95



Dry


15
BMC - 2400
90
10:1
10.5
10.0
96



Dry


16
BMC - 450
90
10:1
9.5
7.9
130









The tests for evaluating the performance of the depressor are described in the table below.
















Mass




recovery
Chemical Analysis (%)















Test
Flow
(%)
Fe
SiO2
P
Al2O3
Mn
TiO2





01
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
47.49
68.16
0.54
0.054
0.31
0.062
0.019



trate



Reject
52.51
27.08
60.56
0.012
0.34
0.007
0.001


02
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
49.25
67.86
0.47
0.052
0.33
0.059
0.016



trate



Reject
50.75
23.87
64.76
0.007
0.32
0.001
0.001


03
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
16.90
66.73
0.87
0.088
0.41
0.124
0.015



trate



Reject
83.10
41.96
38.32
0.020
0.34
0.018
0.005


04
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
20.43
66.77
1.09
0.083
0.39
0.120
0.013



trate



Reject
79.57
40.49
40.77
0.017
0.31
0.006
0.006


05
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
15.83
65.68
1.06
0.088
0.46
0.134
0.015



trate



Reject
84.17
42.03
39.08
0.017
0.29
0.008
0.005


06
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
12.32
65.84
0.82
0.095
0.45
0.148
0.012



trate



Reject
87.68
43.01
37.25
0.020
0.29
0.013
0.005


07
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
21.57
66.34
1.20
0.080
0.42
0.123
0.014



trate



Reject
78.43
40.10
41.56
0.016
0.30
0.004
0.005


08
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
13.46
66.11
0.75
0.096
0.43
0.149
0.012



trate



Reject
86.54
42.56
37.56
0.019
0.30
0.011
0.006


09
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
14.84
65.91
0.90
0.087
0.40
0.130
0.013



trate



Reject
85.16
42.11
38.29
0.018
0.29
0.012
0.006


10
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
22.79
65.89
0.95
0.077
0.34
0.098
0.012



trate



Reject
77.21
39.56
42.03
0.015
0.33
0.009
0.003


11
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
42.05
67.35
0.87
0.056
0.28
0.069
0.016



trate



Reject
57.95
29.74
57.04
0.011
0.34
0.003
0.001


12
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
45.31
66.84
1.38
0.059
0.31
0.068
0.016



trate



Reject
54.69
28.00
59.86
0.005
0.30
0.001
0.001


13
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
65.01
63.20
6.96
0.041
0.27
0.050
0.016



trate



Reject
34.99
10.92
82.58
0.004
0.36
0.001
0.001


14
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
47.22
66.85
1.55
0.054
0.31
0.066
0.018



trate



Reject
52.78
26.99
60.99
0.005
0.31
0.001
0.001


15
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
67.45
60.16
11.39
0.040
0.30
0.046
0.012



trate



Reject
32.55
15.23
77.71
0.003
0.34
0.001
0.001


16
Feed
100.00
45.70
33.89
0.032
0.28
0.031
0.008



Concen-
30.60
66.02
1.86
0.067
0.35
0.090
0.014



trate



Reject
69.40
36.39
46.58
0.009
0.29
0.001
0.001













Mass




recovery
Chemical Analysis (%)












Test
Flow
(%)
CaO
MgO
PPC





01
Feed
100.00
0.001
0.001
1.35



Concentrate
47.49
0.001
0.001
2.16



Reject
52.51
0.001
0.001
0.75


02
Feed
100.00
0.001
0.001
1.35



Concentrate
49.25
0.001
0.001
2.15



Reject
50.75
0.001
0.001
0.59


03
Feed
100.00
0.001
0.001
1.35



Concentrate
16.90
0.001
0.001
3.68



Reject
83.10
0.001
0.001
1.09


04
Feed
100.00
0.001
0.001
1.35



Concentrate
20.43
0.001
0.001
3.43



Reject
79.57
0.001
0.001
0.83


05
Feed
100.00
0.001
0.001
1.35



Concentrate
15.83
0.001
0.001
3.72



Reject
84.17
0.001
0.001
0.87


06
Feed
100.00
0.001
0.001
1.35



Concentrate
12.32
0.001
0.001
4.03



Reject
87.68
0.001
0.001
0.95


07
Feed
100.00
0.001
0.001
1.35



Concentrate
21.57
0.002
0.001
3.53



Reject
78.43
0.001
0.001
0.73


08
Feed
100.00
0.001
0.001
1.35



Concentrate
13.46
0.001
0.001
4.02



Reject
86.54
0.001
0.001
0.93


09
Feed
100.00
0.001
0.001
1.35



Concentrate
14.84
0.001
0.001
3.77



Reject
85.16
0.001
0.001
0.90


10
Feed
100.00
0.001
0.001
1.35



Concentrate
22.79
0.005
0.001
3.44



Reject
77.21
0.001
0.001
0.84


11
Feed
100.00
0.001
0.001
1.35



Concentrate
42.05
0.001
0.001
2.58



Reject
57.95
0.001
0.001
0.60


12
Feed
100.00
0.001
0.001
1.35



Concentrate
45.31
0.001
0.001
2.44



Reject
54.69
0.001
0.001
0.48


13
Feed
100.00
0.001
0.001
1.35



Concentrate
65.01
0.001
0.001
2.03



Reject
34.99
0.001
0.001
0.48


14
Feed
100.00
0.001
0.001
1.35



Concentrate
47.22
0.001
0.001
2.38



Reject
52.78
0.001
0.001
0.50


15
Feed
100.00
0.001
0.001
1.35



Concentrate
67.45
0.001
0.001
1.94



Reject
32.55
0.001
0.001
0.54


16
Feed
100.00
0.001
0.001
1.35



Concentrate
30.60
0.001
0.001
2.94



Reject
69.40
0.001
0.001
0.66









It is possible to conclude that the depressor comprising sugar cane bagasse works. Furthermore, it can be noted that the best performance of the flotation, in terms of yield mass and optimum content of SiO2 in the concentrate, was obtained in test 12, with dosage of BMC (depressor) at 1200 g/t fed, amine dosage at 90 g/t SiO2, ratio BMC/caustic soda 10:1 and pH 10.5.
Based on this result, new tests were carried out with greater dosages of the depressor and a low dosage of amine 90 g/t SiO2. The parameters used for the flotation tests are shown in table below.

















Amine






Depressor
EDA-C


Time of


Test
(g/t)
(g/t SiO2)
pH Test
pH Final
Test(s)




















01
800
90
10.50
9.8
120


02
1000
90
10.50
8.9
118


03
1100
90
10.50
9.8
119


04
1300
90
10.50
9.5
121


05
1400
90
10.50
9.8
115


06
1500
90
10.50
9.9
121


07
1600
90
10.50
9.9
122


08
2000
90
10.50
9.9
119









The table below shows the results obtained with these new parameters:
















Mass




recovery
Chemical Analysis (%)















Test
Flow
(%)
Fe
SiO2
P
Al2O3
Mn
PPC





01
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
44.15
66.56
1.06
0.062
0.44
0.062
2.44



trate



Reject
55.85
27.38
59.79
0.008
0.39
0.001
0.48


02
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
45.52
67.20
1.45
0.058
0.44
0.065
2.44



trate



Reject
54.48
27.58
60.03
0.008
0.19
0.009
0.45


03
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
50.36
67.61
1.13
0.053
0.44
0.060
2.29



trate



Reject
49.64
23.05
67.15
0.005
0.41
0.001
0.43


04
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
54.38
67.01
1.07
0.052
0.43
0.056
2.13



trate



Reject
45.62
19.46
71.51
0.004
0.47
0.001
0.45


05
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
56.31
67.06
1.20
0.051
0.44
0.054
2.02



trate



Reject
43.69
16.74
74.68
0.009
0.46
0.001
0.44


06
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
56.59
67.46
1.38
0.053
0.44
0.054
2.13



trate



Reject
43.41
16.45
75.60
0.004
0.42
0.001
0.44


07
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
57.89
66.79
2.27
0.046
0.42
0.054
2.11



trate



Reject
42.11
15.79
76.26
0.003
0.43
0.001
0.45


08
Feed
100.00
45.70
33.89
0.032
0.28
0.031
1.35



Concen-
63.87
63.36
7.77
0.043
0.40
0.049
2.00



trate



Reject
36.13
13.24
79.27
0.004
0.42
0.001
0.47













Mass




recovery
Chemical Analysis (%)













Test
Flow
(%)
TiO2
CaO
MgO
PPC





01
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
44.15
0.019
0.012
0.254
2.44



Reject
55.85
0.001
0.008
0.215
0.48


02
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
45.52
0.019
0.015
0.001
2.44



Reject
54.48
0.001
0.013
0.001
0.45


03
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
50.36
0.018
0.017
0.001
2.29



Reject
49.64
0.001
0.008
0.001
0.43


04
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
54.38
0.020
0.021
0.001
2.13



Reject
45.62
0.001
0.019
0.001
0.45


05
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
56.31
0.020
0.019
0.001
2.02



Reject
43.69
0.001
0.023
0.001
0.44


06
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
56.59
0.020
0.026
0.001
2.13



Reject
43.41
0.001
0.014
0.001
0.44


07
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
57.89
0.021
0.013
0.001
2.11



Reject
42.11
0.001
0.012
0.001
0.45


08
Feed
100.00
0.008
0.001
0.001
1.35



Concentrate
63.87
0.017
0.011
0.001
2.00



Reject
36.13
0.001
0.008
0.001
0.47









It is noted that with the use of lower dosages of amine excellent results were obtained in the quality of the concentrate and mass yield. The tests confirm the use of cane bagasse as a depressor of iron ore in reverse flotation.

## Claims

1. A process of preparing a depressor in iron ore flotation, comprising:
a. mixing sugar cane bagasse with water, obtaining a first mixture comprising the sugar cane bagasse and the water;
b. adding caustic soda to the first mixture at a weight ratio of 6:1 to 10:1 of sugar cane bagasse:caustic soda, thereby obtaining a second mixture comprising the sugar cane bagasse, the water, and the caustic soda;
c. letting the second mixture stand;
d. adding additional water to the second mixture, thereby obtaining a third mixture comprising the sugar cane bagasse, the water, the caustic soda, and the additional water, and
e. agitating.

2. The process of preparing a depressor in iron flotation of claim 1, wherein said ratio between bagasse: caustic soda is preferably 8:1.

3. The process according to claim 1, wherein the caustic soda is added to the first mixture at a weight ratio of 8:1 part of sugar cane bagasse:caustic soda.

4. The process according to claim 1, wherein in step “c” the second mixture stands for 30 minutes.

5. The process according to claim 1, wherein water is added until reaching 1000 ml.

6. The process according to claim 1, wherein the agitating includes agitation for 10 minutes in a mechanical agitator.

7. The process according to claim 1, wherein the pH is between 9.5 and 11.0.

8. A process of preparing a depressor in iron ore flotation, comprising:
measuring a mass of an amount of sugar cane bagasse;
drying the sugar cane bagasse in a hothouse at a temperature of 105° C for about 2 hours;
withdrawing the sugar cane bagasse from the hothouse and letting the sugar cane bagasse cool for about 10 minutes;
measuring the mass of the sugar cane bagasse after the cooling;
calculating a humidity of the sugar cane bagasse based on the mass measured prior to the drying and the mass measured after the cooling;
adding a first water into a recipient and agitating with an agitator;
adding the sugar cane bagasse into the recipient and waiting for about 10 minutes to obtain a first mixture;
slowing adding a solution of caustic soda to the recipient to obtain a second mixture;
adjusting a rotation of the agitator so as to maintain a homogeneous solution of the second mixture during gelatinization;
waiting for about 20 minutes for full gelatinization;
adding into the recipient a second water and waiting for about 10 minutes to obtain a third mixture;
switching off the agitator after 10 minutes;
protecting the third mixture from contaminations; and
after preparing the third mixture, checking a concentration using of the third mixture via a refractometer.

9. A depressor in iron ore flotation, comprising:
sugar cane bagasse;
NaOH; and
water;
wherein a weight ratio of the sugar cane bagasse to the NaOH is in a range from 6:1 to 10:1.

10. A method of assisting iron ore floatation in a suspension comprising iron ore, the method comprising:
adding a depressor to the suspension including iron ore, wherein the depressor comprises sugar cane bagasse.

11. A process of preparing a depressor in iron ore flotation, comprising:
measuring a mass of a first amount of sugar cane bagasse;
drying the first amount of the sugar cane bagasse in a hothouse after the measuring;
measuring the mass of the first amount of sugar cane bagasse after the drying;
calculating a humidity of the sugar cane bagasse based on the mass measured prior to the drying and the mass measured after the drying;
calculating a second amount of the sugar cane bagasse and an amount of a caustic soda sufficient to provide a predetermined concentration and a predetermined mass of the depressor based on the calculated humidity;
mixing the second amount of the sugar cane bagasse with a first water to obtain a first mixture;
adding the calculated amount of the caustic soda to the first mixture to obtain a second mixture; and
adding a second water to the second mixture to obtain a third mixture.

12. The process of claim 11, further comprising:
calculating an amount of the first water based on the predetermined mass of the depressor, the second amount of the sugar cane bagasse, and the amount of the caustic soda; and
calculating an amount of the second water based on the predetermined mass of the depressor, the second amount for the sugar cane bagasse, the amount of the caustic soda, and the amount of the first water;
wherein the mixing includes mixing using the calculated amount of the first water; and
wherein the adding includes adding using the calculated amount of the second water.

13. The process of claim 11, further comprising allowing the second mixture to fully gelatinize.

14. The process of claim 11, further comprising agitating during the mixing of the second amount of sugar cane bagasse with the first water, during the adding of the amount of the caustic soda to the first mixture, and during the adding of the second water to the second mixture.

15. The process of claim 11, wherein the caustic soda comprises NaOH.

16. The process of claim 11, further comprising checking a concentration of the third mixture via a refractometer.