The collection mechanism of molybdenum ore by polar collector and its application in flotation of molybdenum sulfide ore

2019-11-26 11:03:15
Molybdenite with "heteropolar surface" has a high surface energy "edge" formed by ionic bond and covalent bond cleavage, in addition to the "surface" of low surface energy formed by molecular bond cleavage. Nishimura allowed reported on the surface of the "edge" can be up to 0.7J / m 2 which is a hydrocarbon oil of low surface energy 3 × 10 -2 J / m 2 far, the key is also different. It was observed that the paraffin droplets could be fixed on the "face" of the clean molybdenum ore, but could not be fixed on the "edge". Obviously, when capturing molybdenum ore with hydrocarbon oil, the hydrocarbon oil is mainly adsorbed on the low energy "face" of the molybdenum ore.
The "rib" surface of molybdenum ore is arranged in a certain proportion by molybdenum atoms and sulfur atoms. It has been found that the action of the anionic collector on the "rib" surface is similar to that on other sulfide mineral surfaces.
J. Ryan sub information reported, some of the metal thio compounds (including Ge 4+, As 5+, Mo 4+ , Sb 5+, W 6+, Hg 2+), in particular metal xanthate class, having A strong tendency to form complexes with elemental sulfur or ionized sulfur. The ligand can be formed not only simple transition metal - ligand complex is also formed NO, CN comprising - a number of mixed ligand complex ligand, pyridine, amines and the like. J. Ria also introduced the complexes that may be seen in molybdenite flotation: MoO 3 (X) 4 (X is xanthate ion ROCS 2 - ), when it interacts with CN - , can be CN - Substituting X - ; when it acts with H 2 S or RSH, it forms molybdenum sulfide yellow drug MoS 2 (X) or sulfur yellow drug MoS (RS) X.
Gould (Golld) 1972 Determination of the IR diethyl disulfide phosphate molybdenite action over the surface, the characteristic infrared peaks found that Mo (DTP) X is 640,615,527cm -1. (DTP - diethyldithiophosphate).
The amount of xanthogen ion adsorption was determined by the surface of various sulfide minerals that had been treated with potassium ethylxanthate solution by Jing Zi et al. According to the formula, the adsorption amount г=a [X - ] 1/ n
MoS 2 a=4.96×10 -5 1/ n=0.28 FeS 2 a=2.58×10 -6 1/ n=0.38
HgS a=2.12×10 -5 1/ n=0.32 Sb 2 S 3 a=3.98×10 -6 1/ n=0.45
PbS a=5.24×10 -5 1/ n=0.33
In contrast, at the same xanthogen ion concentration [X - ], the amount of adsorption on the molybdenum ore is greater.
Studies by C.H. Mitrovofov and A.B. Kurochkina pointed out that the amount of xanthate and black drug adsorbed by molybdenite varies with pH (see Figure 1).

Figure 1 Adsorption of xanthate on molybdenite at different pH values ​​(concentration 5mg/L)
When the blackening agent (diethyldithiophosphate) or xanthate is at a low concentration (5mg/L), the molybdenum ore has a particle size of 0.3~0.44mm, and the specific surface area is 332cm 2 /g, the molybdenite The maximum adsorption value was 2.4×10 -2 mg/g (corresponding to black medicine) and 7.0×10 -7 mg/g (corresponding to xanthate). Moreover, when pH = 6, the amount of xanthate adsorption is the largest, while the amount of black drug adsorption has been decreasing with increasing pH. When the molybdenite is pretreated with hydrocarbon oil, the adsorption amount of xanthate and black drug can be reduced. [next]
Obviously, polar thio compounds (xanthine, black medicine, mercaptan, etc.) can be well adsorbed on the "soak" surface of molybdenite.
According to the measured value of Xing Yongqing, in the conventional flotation particle size range, the molybdenite fracture surface is dominated by “face” and the proportion of “edge” is less. At this point, polar thio compounds are typically only used as auxiliary collectors for hydrocarbon oils. Yang Jiazhangzi Molybdenum Company found that as an auxiliary collector, the amount of yellow drug does not have to be too large, about 10g/t, see Figure 2, and the test results are shown in Table 1.

Figure 2 Effect of yellow medicinal amount on molybdenum ore flotation

Table 1 Effect of adding xanthate on coarse selection of molybdenum ore

Dosage amount (g/t)
PH
Mineral processing index (%)
Coal oil
2 #æ²¹
Water glass
Yellow medicine
Yield
Coarse concentrate
Tailings molybdenum content
Molybdenum recovery
140
140
140
50
50
50
0
0
1000
0
10
10
7
7
7.5
4.06
4.62
4.59
2.46
2.29
2.30
0.0098
0.0087
0.0069
91.80
92.73
94.13

Obviously, while adding kerosene, the addition of xanthate increased the molybdenum recovery rate by about 1%, and then added the slime dispersion and the inhibitor water glass. The recovery rate of molybdenum further increased, and the total increase rate was more than 2%.
The molybdenum ore in the crushing zone of Yangjiazhangzi Mine is often wrapped in a film shape, which is difficult to dissociate from the monomer, and the surface is dull. It is covered with an oxide layer such as molybdenum-calcium ore. The recovery rate of the rough selection is usually only 50%, and only 30 is mixed. % mixed ore crushed ore, the crude recovery rate is only 83~85%. For this "oxidized" ore, the polar agent xanthate is added. If the activator CuSO 4 is added to improve the recovery rate of molybdenite, see Table 2.

Table 2 Test of flotation containing 30% crushed ore

Dosage amount (g/t)
PH
Mineral processing index (%)
kerosene
2# oil
Water glass
CuSO 4
Yellow medicine
Yield
Coarse concentrate
Tailings molybdenum content
Molybdenum recovery
180
180
180
35
40
40
0
2000
2000
0
0
20
0
20
20
7.0
8.0
7.5
3.75
3.60
3.67
3.46
3.61
3.97
0.0258
0.0167
0.0145
83.94
88.98
91.25

The study found that: butyl xanthate is better than ethyl xanthate, isopropyl xanthate is better than butyl xanthate. In 1988, Yangjiazhangzi molybdenum selection plant used sodium black medicine instead of xanthate to complete industrial test, molybdenum recovery rate. Also increased by about 1% on the basis of xanthate.
Abroad, as a good collector of various sulfide minerals, n-dodecyl mercaptan, has begun to be used for molybdenum beneficiation. A. Shevis was the earliest researcher. In 1978 and 1980, he obtained patents in South Africa, Brazil, and the United States. In 1980, he was applied in the Pelaybola Mining Company in South Africa. The Hazen Institute also began a similar study in 1977. The Pennfloat(TM) 3 agent sold by Pennwater is now a mixture of n-dodecyl mercaptan and a water-soluble dispersant.
The n-dodecyl mercaptan has a strong collection performance, but the solubility, water oil and dissociation are very low: S = 5.9 × 10 -8 mol / L, HLB (calculated by the small field ratio method) = 0.713, pK a =15.7. Clearly, dispersion and solubilization are extremely important. [next]
Douglas R. Shaw Information describes the application of molybdenum beneficiation. All of the copper -molybdenum ores examined have shown that after the use of dodecyl sulphate, the recovery rate of molybdenum is significantly increased by 5% to 40% higher than that of common collectors, as shown in Figure 3, See Table 3 and Figure 4 for the effect of dodecyl mercaptan instead of steam oil and Xintex on molybdenum ore.

Figure 3 Effect of molybdenum flotation on the amount of dodecyl mercaptan

Table 3 Dodecyl mercaptan collection effect (roughing operation)

Mineral sample
Collector
product
Yield(%)
Grade (%MoS2)
Distribution rate (%)
name
Dosage (g/t)
Steam oil
Xintex
145
15
Concentrate
6.04
3.95
90.8
Tailings
93.96
0.026
9.2
A
Dodecyl mercaptan
Pennfloat 3
85
Concentrate
10.44
3.78
97.3
Tailings
89.56
0.012
2.7
Ibid.
45
Concentrate
8.58
4.02
96.6
Tailings
91.42
0.013
3.4
Dodecyl mercaptan
Pennfloat 3
20
Concentrate
6.53
4.01
94.3
Tailings
93.47
0.017
5.7
B
Steam oil
Xintex
255
18
Concentrate
5.22
4.89
95.4
Tailings
94.78
0.13
4.6
Dodecyl mercaptan
Pennfloat 3
72
Concentrate
5.41
4.66
95.0
Tailings
94.59
0.013
5.0
Dodecyl sulfur
Pennfloat 3
40
Concentrate
5.65
4.55
93.9
Tailings
94.95
0.013
6.1

Figure 4 Relationship between the grade of molybdenite coarse concentrate and recovery rate

The author used dodecyl mercaptan to study the Jinduicheng, Luanchuan and Huangshan molybdenum ores and found that the dodecyl mercaptan was similar to the kerosene flotation when no dispersant was added. When a water-soluble dispersant is added, the dodecyl mercaptan collection effect is significantly better than kerosene. In particular, in 1983, the use of dodecyl mercaptan with dispersant to select the molybdenum ore in the Huangshan molybdenum ore (oxidation rate of about 15%) was about 10% higher than that with kerosene (see Table 4). This study confirmed that the solubility of dodecyl mercaptan is very low, and it is difficult to exert its effect without adding a dispersing agent. The dispersant is better with nonylphenol-based polyoxyethylene ether (POE) (water oil HLB=12~14).

Table 4 Effect of dodecyl mercaptan on molybdenum ore selection
Mineral sample
Dosage amount (g/t)
Flotation indicator (%)
2 #æ²¹
kerosene
Dodecyl mercaptan
Dispersant
Raw ore grade
Concentrate grade
Molybdenum recovery
A
95
120
0.185
4.50
93.34
120
180
0.190
3.19
95.42
95
20
0.185
2.41
96.27
95
40
0.178
2.42
95.61
95
80
0.183
2.51
95.90
B
120
200
0.197
4.91
67.82
120
250
0.191
4.80
66.09
80
20
Ether alcohol
0.209
3.72
68.63
80
20
SF 8
0.204
2.79
72.16
80
20
SF 8
0.207
3.42
79.86
80
10
SF 8
0.180
3.06
77.33
Note: (1) Mineral sample A is an easy-to-select ore; (2) Mineral sample B is a refractory molybdenum ore with an oxidation rate of about 15%;
(3) The dispersing agent SF 8 is an ionic surfactant; (4) the dispersing agent SF 8 is a nonionic surfactant.

The polar collector utilizes the polar adsorption of molybdenum "edge" to make the surface of the molybdenite hydrophobic and float. However, polar agents can also capture the associated non-molybdenum sulfide minerals, which greatly increases the amount of Cu and Fe in the coarse concentrate, which makes it difficult to select molybdenum. Douglas R. Shaw pointed out that adding molybdenum or high-dose inhibitors to molybdenum selection operations can overcome this difficulty and improve the quality of molybdenum concentrate. When combined Yangjiazhangzi kerosene, xanthate collector molybdenite, galena, pyrite content in the crude concentrate increased substantially, but selection of sodium cyanide was added as an inhibitor to the phosphorus Knox After that, a fully qualified molybdenum concentrate can be obtained.

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