TABLE 2

Influence of Molar Ratio of Secondary Reaction

on Chlorine Removal Effect and Cuprous Chloride

NaCl:Cu₂O
1:0.25
1:0.2
1:0.15
1:0.1
1:0.08
1:0.05

Corresponding primary reaction
1:0.25
1:0.3
1:0.35
1:0.4
1:0.4
1:0.45

Chlorine removal rate (%)
48.63
38.91
29.36
19.56
18.86
9.85

Product purity (%)
96.05
96.39
96.14
96.26
96.61
92.14

Product yield (%)
91.25
91.42
90.89
90.52
89.53
89.21

Reaction conditions: initial Cl⁻ (30 g/L), pH value=2.5, room temperature, 10 min, and stirring speed 400 r/min.

Example 2

Taking Example 1 of adding by 80% in the primary reaction and adding by 16% in the secondary reaction as an example, the time of a reaction with stirring was changed to 2, 5, 8, 10 (Example 1), 12 and 15 min. Other operating steps were the same as those in Example 1. The results are shown in Table 3. It can be seen that when the reaction stirring time was 10 to 15 min, not only could the chlorine removal rate be ensured, but also it could be ensured that the purity of the cuprous chloride was not less than 96%. An optimal reaction effect was achieved at about 10 min. After that, a further reaction might lead to release of chloride ions and oxidation and dismutation of cuprous ions, such that the product purity was slightly reduced. It was most preferred that the time was controlled at 10 to 12 min.

TABLE 3

Influence of Reaction Stirring Time on Overall

Chlorine Removal Effect and Cuprous Chloride

T/min
2
5
8
10
12
15

Chlorine removal rate (%)
62.19
82.74
90.64
95.10
95.10
92.47

Product purity (%)
67.42
84.95
93.10
97.89
97.55
96.54

Product yield (%)
94.92
92.43
89.34
88.1
87.5
87.7

Reaction conditions: initial Cl⁻ (30 g/L), pH value=2.5, room temperature, stirring speed 400 r/min, and adding by 80%+16%.

Example 3

Taking Example 1 of adding by 80% in the primary reaction and adding by 16% in the secondary reaction as an example, the reaction stirring speed in Example 1 was changed to 200 r/min and 600 r/min. Other operating parameters were consistent with those in Example 1. The results are shown in Table 4. It can be seen that the stirring speed had little influence on the product.

TABLE 4

Influence of Stirring speed on Overall Portion-wise

Chlorine Removal Effect and Cuprous Chloride

r/min
200
400
600

Chlorine removal rate (%)
95.02
95.10
95.05

Product purity (%)
97.73
97.89
97.84

Product yield (%)
88.6
88.1
88.3

Reaction conditions: initial Cl⁻ (30 g/L), pH value=2.5, room temperature, and reacting with stirring for 10 min.

Example 4

Taking Example 1 of adding by 80% in the primary reaction and adding by 16% in the secondary reaction as an example, the initial concentration of chloride ions in Example 1 was changed to 10, 40, 50 and 100 g/L, respectively. Other operating parameters were consistent with those in Example 1. The results are shown in Table 5.

It can be seen that the initial concentration of chloride ions shall not be too high. To ensure the product purity, the initial concentration shall be controlled to be 100 g/L or below, preferably not exceeding 50 g/L, and more preferably 30 g/L or below.

TABLE 5

Influence of Cl⁻ Concentration on Overall

Chlorine Removal Effect and Cuprous Chloride

g/L
10
30
40
50
100

Chlorine removal rate (%)
96.23
95.10
94.58
93.71
90.53

Product purity (%)
97.93
97.89
97.59
95.87
93.68

Product yield (%)
88.2
88.1
89.2
89.7
91.4

Reaction conditions: pH value=2.5, room temperature, 10 min, and stirring speed 400 r/min.

Example 5

(1) Primary reaction: preparation of crude cuprous chloride: 100 ml of fly ash water washing solution (Cl⁻ concentration of 30 g/L) was taken. Air was introduced into a system for 4 h. In a case where it was detected that pH was around 7, sulfuric acid was dropwise added until pH was 2.5. After that, Cu₂O (added at once) was added by 80% of the theoretical addition amount of cuprous oxide (6.05 g). During the period, the sulfuric acid was continuously added to maintain the pH at around 2.5. Stirring was performed at room temperature for 10 min. Centrifugation was performed after the reaction to obtain crude cuprous chloride and supernatant. The crude cuprous chloride was subjected to post-treatment. The supernatant was to be subjected to the secondary reaction.

(2) Secondary reaction: the supernatant obtained in step (1) was taken. Cu₂O was added such that the total addition amount in step (1) and step (2) was 96% of the theoretical addition amount (added at once). The primary reaction was repeated with same steps. After the reaction, crude cuprous chloride was obtained, and was merged with a primary reaction product. The Cl⁻ concentration decreased to 2.97 g/L after the supernatant reacted, and the chlorine removal effect reached 90.1%.

(3) Product post-treatment: acid washing: 80 ml of sulfuric acid solution with pH=2.6 was added to wash the above-mentioned crude product, centrifugation was performed again, and the operations were repeated twice to obtain acid-washed cuprous chloride. Ethanol washing: a certain volume of anhydrous ethanol was added to further wash the above-mentioned cuprous chloride, centrifugation was performed, and the operations were repeated twice to obtain ethanol-washed cuprous chloride. Drying: the above-mentioned cuprous chloride was placed in a vacuum drying oven and dried at 45° C. for 60 min to obtain 5.15 g of cuprous chloride product, with a yield of 85.2%, and the product purity was determined to be 95.16%. A reaction solution was merged for water washing of fly ash.

Example 6

Taking Example 1 of adding by 80% in the primary reaction and adding by 16% in the secondary reaction as an example, a stirring reaction process was performed in an oxygen-free environment (protected by introducing nitrogen gas). Other operating steps and parameters were the same as those in Example. The results showed that after the supernatant reacted, the concentration of Cl⁻ decreased to 1.41 g/L, and the chlorine removal effect reached 95.3%. 5.40 g of cuprous chloride product was obtained, with a yield of 89.4%, and the product purity was determined to be 98.56%. It can be seen that the oxygen-free environment can slightly improve the treatment effect, but the improvement is not significant.

Example 7

Preparation of crude cuprous chloride: 100 ml of fly ash water washing solution (Cl⁻ concentration of 30 g/L) was taken. Air was introduced into a system for 4 h. In a case where it was detected that pH was around 7, sulfuric acid was dropwise added until pH was 0.5, 1, 1.5 and 2. After that, Cu₂O was added in portions (added in three portions by 62.5%, 25% and 12.5% of the addition amount in sequence, with an interval of 1 min) by theoretical NaCl:Cu₂O=1:0.5. During this period, the sulfuric acid was continuously added to maintain the pH or the sulfuric acid was added at once (the total amount of the sulfuric acid was consistent). Stirring was performed at room temperature for 10 min. Centrifugation was performed after the reaction to obtain crude cuprous chloride and supernatant. The crude cuprous chloride was subjected to post-treatment.

The results are shown in Table 6. It can be seen that in a case of the same amount of sulfuric acid, when the sulfuric acid was continuously added to maintain a stable state of the pH value of the system, a better chlorine removal effect and a higher-purity product can be obtained.

TABLE 6

Comparison Between Addition at Once and Continuous Addition of Sulfuric Acid

pH value

0.5
1
1.5
2

Sulfuric acid addition manner