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Figure 3 Figure 4
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Air contains oxygen, nitrogen, carbon dioxide, and other ingredients, when a large amount of air into the flotation pulp in the flotation of non-ferrous metal minerals, pulp, various metal ions, so the study of oxygen, carbon dioxide, and metal ions on dilution Yellow The effects of drug stability are necessary.
When oxygen is bubbled, the decomposition of xanthate takes 0.1ml of 0.1M xanthate solution at 25±1°C, and 0.5 liters of oxygen per minute is added. The xanthate is decomposed according to the following reaction formula:
The test results are shown in Table 1. As seen from Table 1, ethyl, n-butyl, isoamyl xanthate, i.e., the first alcohol xanthate, is less oxidized, and isopropyl xanthate (second alcohol xanthate) is more susceptible to oxidation. At the same time, it can be seen that in the first alcohol yellow drug, the longer the hydrocarbon group is, the more difficult it is to be oxidized, and the more stable the oxidation property. Ethyl xanthate and isopropyl xanthate are less decomposed, and are about 60 to 70% of the decomposition of butyl xanthate and isoamyl xanthate.
Effect of oxygen on yellow decomposition Table 1
Drum into the oxygen
Gas time
(hour)
Xanthate
Isopropyl xanthate
N-butyl xanthate
Isoamyl xanthate
Oxidation (%)
break down(%)
Oxidation (%)
break down(%)
Oxidation (%)
break down(%)
Oxidation (%)
break down(%)
0
1
2
3
4
5
6
no
0.7
1.6
2.0
2.0
2.0
2.0
no
1.0
2.0
2.0
3.0
3.0
3.0
no
1.3
4.1
5.9
7.9
8.4
8.8
no
1.0
1.0
1.0
1.0
2.0
3.0
no
0.4
0.4
0.4
0.4
0.4
0.4
no
1.0
2.0
3.0
3.8
4.4
4.7
no
0.0
0.0
0.0
0.0
0.0
0.0
no
1.1
1.7
2.5
3.6
4.0
4.0
2, the effect of the mixture of oxygen and carbon dioxide on the stability of xanthate with 200 ml of 0.1M xanthate solution, at 25 ± 1 ° C, both O 2 and CO 2 gas velocity is 0.25 l / min, The experimental results are shown in Table 2. When O 2 and CO 2 are blasted into the xanthate solution, the following reaction occurs:
O 2 and CO 2 mixed gases affect the decomposition results of xanthate Table 2
Passing gas time
(hour)
Yellow drug decomposition (%)
Ethyl xanthate
Isopropyl xanthate
N-propyl xanthate
Isoamyl xanthate
0
0.5
1.0
1.5
2.0
2.5
3.0
4.0
5.0
6.0
Oxidation to dihuang medicine (%)
no
2.0
3.0
4.0
4.3
4.7
5.0
5.7
6.1
6.1
1.2
no
3.0
4.0
5.1
6.1
6.8
7.2
8.2
9.2
10.2
2.6
no
2.5
3.1
3.6
4.0
4.2
4.5
5.0
5.3
5.6
1.0
no
3.4
4.0
4.5
4.8
5.2
5.5
5.7
5.7
5.7
1.0
Comparing Table 1 and Table 21, it can be seen that the lower grade xanthate (ethyl xanthate, isopropyl xanthate) is reduced by the oxidation of oxygen and carbon dioxide mixed gas, and the advanced xanthate (butyl xanthate, isoamyl xanthate) ) raised the degree of oxidation; again seen from table 2, there isopropyl xanthate in presence of CO 2 and O 2 under the most susceptible to oxidation; CO.'s 2 and O 2 have exist when he xanthate solution More prominent than the presence of O 2 alone.
3, the effect of carbon dioxide on the decomposition of xanthate with 200 ml of 0.1M xanthate solution, blasting CO 2 gas at 25 ± 1 ° C, the speed is 0.25 l / min, in the presence of CO 2 , xanthate decomposition Produce carbon disulfide and alcohol:
The test results are shown in Figure 1.
Figure 1 Figure 2 [next]
It can be seen from Fig. 1 that under the same conditions, the most decomposed is ethylxanthate, the hydrocarbon group of xanthate is increased, and the degree of decomposition is decreased; in the presence of oxygen, the degree of decomposition of isopropyl xanthate is the largest.
4, the effect of dilution on the decomposition of xanthate at 25 ± 1 ° C, with 200 ml of 0.1 M amyl xanthate, the oxygen rate of 0.5 l / min, while using 200 ml of 0.01 M amyl xanthate to do the same test, To compare their results, the results are plotted in Figure 2.
At 25 ± 1 ° C, 200 ml each of 0.1 M and 0.01 M amyl xanthate were introduced, and a mixture of O 2 and CO 2 was introduced at a rate of 0.25 L/min. The results of oxygen tilting and decomposition are shown in Fig. 3.
Similarly, at 25 ± 1 ° C, respectively, 0.1 M and 0.1 M amyl xanthate 200 ml each, the rate of CO 2 was 0.25 L / min, the decomposition results of amyl xanthate are shown in Figure 4.
As seen from Fig. 2, Fig. 3 and Fig. 4, in all cases, the percentage of decomposition of xanthate in the dilute solution is increased because the ratio of the gas introduced into the dilute solution to the weight of the xanthate is higher. High in concentrated solution.
5. Transitional element ions or ions capable of forming insoluble solvate with xanthate have a catalytic effect on the decomposition of xanthate in aqueous solution of xanthate. According to the literature, many people measure the half-life of xanthate. One of the different reasons is that during the measurement process, the xanthate solution contains trace amounts of various transition element ions of different amounts. It can be seen from Table 3 that in the presence of N 2 work O 2 , due to the catalysis of certain metal ions, xanthate accelerates decomposition and the decomposition half-life is significantly changed.
Decomposition rate of ethyl potassium xanthate at pH=8 Table 3
Gas present
N 2
O 2
N 2
Added metal ion
-
-
Zn 2+
Mn 2+
Ba 2+
Al 3+
Pb 2+
Ni 2+
Hg 2+
Cu 2+
Sn 2+
Co 2+
Fe 2+
Trace (primary ion)
Decomposition half-life (hours)
520
520
520
500
450
435
435
373
352
335
310
310
236
520
For a further discussion of certain metal ions xanthate catalytic decomposition to Fe 3+ ions, for example, as discussed below, xanthate in 200 ml of 0.1M solution, addition of iron sulfate [Fe 2 (SO 4) 3 ], so that The concentration of Fe 3+ ion in the solution was 0.001 M, and then a mixture of oxygen and carbon dioxide at a rate of 0.25 L/min was introduced (mixed before the pass), and the test results are compared in the data of Table 4 and Table 2, Very clear. It must be pointed out that in the presence of Fe 3+ , the yellow alcohol (yellowxanthin, n-butyl xanthate, n-pentyl xanthate) synthesized by the first alcohol is oxidized by about fifteen times; the second alcohol (isopropyl The base xanthate is about five times more oxidized.
Effect of high-iron ions on the decomposition of xanthate in the presence of O 2 and CO 2
Access to O 2 and CO 2
Time (hours)
Yellow drug decomposition (%)
Ethyl xanthate
Isopropyl xanthate
N-butyl xanthate
Amyl yellow
0
0.5
1.0
1.5
2.0
2.5
3.0
4.0
5.0
6.0
After 6 hours, xanthate is oxidized into double xanthate (%)
0.0
5.2
7.0
9.1
10.9
12.8
14.0
16.7
18.6
20.9
15.3
0.0
5.4
7.4
9.5
11.3
12.4
14.2
16.5
19.0
20.8
12.2
0.0
5.3
7.2
9.1
10.9
12.5
14.1
16.6
18.8
20.7
15.0
0.0
7.5
10.0
11.6
13.4
14.3
16.1
18.2
19.9
21.4
15.7
Why does high-iron ion energy accelerate the oxidation of xanthate? It may be explained that the following reactions occur during the test:
The iron ions generated by the reaction 2 are further reacted with the xanthate which is not tilted by the oxygen, and the circulation is carried out to accelerate the oxidation of the xanthate to the double xanthate. As for the isopropyl xanthate, under the catalysis of Fe 3+ ions, the oxidation is not as fast as the first alcohol xanthate, which may be related to the structure of the xanthate itself.