The basic principle of xanthate as a collector

When the surface of the object acts, its polar part, OCSS , is fixed to the mineral surface, while the non-polar group R is oriented outward. Due to the hydrophobic action of the non-polar groups, the hydrophobicity of the surface of the ore particles is increased. When the ore with the xanthate anion is in contact with the bubble, the non-polar base of the xanthate on the surface of the ore is inserted into the bubble and floats up to the surface of the slurry (below). This is the basic principle of xanthate capture of sulfide ore.

There are two hypotheses about how xanthene attaches to the surface of sulfide minerals, namely the "chemical hypothesis" and the "half oxidation hypothesis." The chemical hypothesis believes that the adhesion of xanthate to the mineral surface is due to an ordinary chemical reaction between the xanthate and the mineral surface. The same metal xanthates solubility product by xanthate non-polar hydrocarbon chain length and structure variations and different hydrocarbon chain length, solubility product is not, and the solubility product is smaller xanthates The better the flotation effect.
As can be seen from the table below, the solubility product of the metal sulfide and the solubility product of the corresponding xanthate is much smaller, and therefore, it is impossible to form a precipitate of xanthate. It is extremely difficult to explain this problem in the chemical hypothesis.

Metal sulfides, xanthates, dithio phosphate solubility product ( 2 5 °C )

Metal cation

Ethyl xanthate

two sulfur generation phosphorus acid Salt (black medicine)

sulfur Chemical Object

Diethyl

Dibutyl

Dimethylphenol

Hg 2+

Ag +

Cu 2+

Pb 2+

Sb 2+

Cd 2+

Ni 2+

Zn 2+

Fe 2+

Mn 2+

1.15 × 10 -38

0.85 × 10 -18

5.2 × 10 -20

1.7 × 10 -17

2 × 10 -24

2.6 × 10 -14

1.4 × 10 -12

4.9 × 10 -9

0.8 × 10 -8

<10 -2

1.1 5 × 10 -32

1. 3 × 10 -16

5. 5 × 10 -17

6. 2 × 10 -12

 

1. 5 × 10 -10

1. 7 × 10 -4

1. 5 × 10 -2

 

 

 

0.4 7 × 10 -18

 

6. 1 × 10 -16

 

3. 8 × 10 -13

 

 

 

 

 

1. 5 × 10 -19

 

1. 8 × 10 -17

 

1. 5 × 10 -12

 

 

 

 

1 × 10 -52

1 × 10 -49

10 -3 8 × 10 -44

1 × 10 -29

 

3. 6 × 10 -29

1. 4 × 10 -24

1. 2 × 10 -23

 

1. 4 × 10 -15

The semi-oxidation hypothesis states that xanthate does not react with products that are completely oxidized on the surface, but rather reacts with a sulfate-bound complex that is slightly oxidized to form a tightly bound lattice:

The insoluble lead xanthate thus formed combines with the PbS in the crystal lattice to form a stable film cover on the surface of the ore particles, so that the ore particles are hydrophobic and easy to float. The surface of lead- vanadium or over-oxidized galena is difficult to dissolve because the complete oxide (such as PbSO 4 ) is easily soluble in water, and the lead xanthate film formed by the reaction of xanthate cannot be firmly combined with the ore. Therefore, it is not easy to float. Experiments have shown that pure galena on the surface cannot be floated with xanthate in the absence of oxygen, but flotation can be carried out as long as a small amount of oxygen is present. This shows that the mechanism of the semi-oxidation hypothesis release agent is relatively correct.

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