Example of treatment and utilization technology of Wankou lead-zinc ore beneficiation wastewater

Fankou lead zinc mine located in the northern part of Guangdong, Guangdong Beijiang River upstream, mineral processing plant daily processing capacity of 4500t, annual output of lead and zinc metal amounted to 150,000 t. Each year, about 10 million m ³ of ore beneficiation wastewater is transported through the sewage transportation system to the tailings dam 12.5 km away from the mine. These beneficiation wastewaters are turbid, high in concentration and high in pH. They contain a variety of organic and inorganic agents, as well as heavy metal pollution factors such as lead, zinc and cadmium . In order to make the discharged wastewater meet the national technical wastewater discharge requirements, technical measures such as acid neutralization, precipitation clarification and separation are adopted, and the annual cost is huge. The comprehensive sewage transportation cost is about 1 yuan/m ³ . If the ore dressing wastewater is effectively clarified and partially or completely replaces the production water, it will not only bring significant economic benefits to the enterprise, but also achieve clean production, protect the environment, and improve the water quality of the Beijiang River system.

I. Sources and characteristics of ore dressing wastewater from Fankou lead-zinc mine

(1) Source of ore dressing wastewater

Fankou mineral wastewater mainly consists of the following components: concentrate wastewater, tailings wastewater, cooling equipment for mineral processing equipment, and washing wastewater from industrial sites. Through the investigation of the beneficiation production process system, the statistical results of the water content of Fankou ore dressing are shown in Table 1.

Table 1 Statistical results of ore dressing wastewater

(II) Characteristics of mineral processing wastewater

The ore dressing wastewater contains a variety of organic and inorganic agents, and the residual agent concentration is high, including lead, zinc, cadmium and other heavy metal ions and compounds, suspended solids, etc., and high pH. The analysis results of ore dressing wastewater and clean water quality are shown in Table 2.

Table 2 Analysis results of ore dressing wastewater and clean water quality

Note: COD _cr a weight measurement method chromate chemical oxygen demand; BOD ₅ to 5d of the chemical oxygen demand; the Do dissolved oxygen; suspension of the SS.

2. Experimental study on settlement of Fangkou mineral wastewater

The wastewater water samples studied in this experiment were taken from the on-site wastewater produced at the site of the plant, including trench wastewater and zinc tail overflow, and the pH values ​​were all above 11.5.

The instruments used in the test mainly include measuring cylinder, analytical balance (1/1000), medicinal balance (1/10), kilogram electronic scale, oven, filter, stopwatch, glass rod, etc. and sample processing tools.

The test method is to install a certain amount of wastewater water sample in a graduated glass measuring cylinder with a diameter of 75 mm, add different amounts of flocculant, stir evenly, and place it on the table to observe its sedimentation effect. The maximum settlement surface required for the settlement of unit solid materials is calculated by a single settlement test algorithm.

The names of the six kinds of wastewater sedimentation agents selected in this experiment and their basic characteristics are shown in Table 3.

Table 3 Selection of ore dressing wastewater

Through the study of the sedimentation test of various sedimentation agents in Table 3 under different dosages, the sedimentation curves of the above six flocculants to Fankou ore dressing wastewater can be obtained. The sedimentation curves are shown in Figures 1-5.

Fig.1 Settlement curve of wastewater water sample under different dosages of DPA150

Fig.2 Settlement curve of wastewater water sample under different dosages of PAM-I

Fig.3 Settlement curve of wastewater water sample under different dosages of PHP-IV

Figure 4 Settlement curve of wastewater water sample under different amounts of SH930

Figure 5 Settlement curve of wastewater water sample under different dosages of 3 ^# flocculant

It can be seen from the sedimentation curves of Fig. 1 to Fig. 5 that the five kinds of medicaments such as DPA150, PMA-I, PHO-IV, SH930 and 3 ^# flocculant have little difference in the sedimentation effect of wastewater water samples under the same dosage conditions, and they have little difference. There is no obvious difference between them. When these chemicals are not added, the sedimentation curve is gentle, indicating that the wastewater is slowly settled, but when a small amount of these agents is added, the sedimentation curve suddenly becomes steep, indicating that the sedimentation effect is very obvious. The wastewater is quickly cleared. However, the addition of FeCl ₃ did not show a significant acceleration of sedimentation.

Experimental studies have shown that in addition to FeCl ₃ , the other five kinds of agents, DPA150, PMA-I, PHO-IV, SH930 and 3 ^# flocculants, can be used as accelerated sedimentation clarification agents for Fankou ore dressing wastewater. And FeCl ₃ can not be used as an accelerated sedimentation clarification agent for Fankou mineral wastewater.

Experimental study on the effect of wastewater sedimentation agents on lead flotation

In the flotation process of Fankou lead-zinc mine, the flotation of lead includes rapid flotation of lead and mixed flotation of lead and zinc. The so-called rapid flotation is flotation when the ore grinding grain size is -0.074mm and the grain size is 85%. , some grades of high-granular coarse galena. This study only discusses the effects of wastewater on the rapid flotation of lead, including rough selection and selection.

(I) Experimental study on the effect of wastewater sedimentation agents on rapid crude selection of lead

In order to explore the effect of the above six kinds of wastewater sedimentation agents on lead flotation, the six sedimentation agents were added to a certain amount of 50% wastewater water samples at different amounts of 0, 2.5, 5, 7.5 g/t (waste water). :Clear water = 1:1), after the sedimentation treatment, the clear liquid is used as the mixing water and brewing water for the flotation operation, and the lead rapid comparison test is carried out. The test process is shown in Figure 6. The test results are shown in Table 4.

Figure 6 rough selection test process

Table 4 Comparison of different types of sedimentation agents for rapid crude selection and lead rough selection

It can be seen from the comparison of the data in Table 4 that the effect of FeCl ₃ on lead flotation is most obvious. With the increase of FeCl ₃ dosage, the grade of lead crude foam drops sharply, followed by DPA150, PMA-I and PHO-IV. When the wastewater sedimentation agent is increased from 0g/t to 7.5g/t, the lead grade decreases by 3% to 6%, and the recovery rate changes by more than 2%. It can be seen that the four kinds of wastewater sedimentation agents have a large lead flotation. influences.

The 3 ^# flocculant and SH930 flocculant used in this test have a relatively small effect on the rough selection of lead when the dosage is less than 5g/t. The difference between the two has little effect on the rough selection of lead. A selection of experimental studies can determine the best pharmaceutical variety.

(B) 3 ^# flocculant and SH930 lead fast selection comparison test

In the rapid crude selection test, 3 ^# flocculant and SH930 were selected as the sedimentation agents for wastewater. In order to further evaluate their effects on lead flotation, further comparative tests of lead rapid selection were needed. The configured 3 ^# flocculant and SH930 are added to 50% of the wastewater water sample in different amounts. After the sedimentation treatment, the clear liquid is used as the slurrying water and brewing water for the flotation operation. The flotation process is shown in the figure. 7. The effect curves of these two flocculants on the grade and recovery rate of fast lead concentrate are shown in Fig. 8 and Fig. 9.

Figure 7 Lead rapid selection test process

Figure 8 3 Effect of ^# flocculant and SH930 on the recovery rate of fast lead concentrate

Figure 9 3 Effect of ^# flocculant and SH930 on the fast lead quality

It can be seen from the comparison curves of Fig. 8 and Fig. 9 that the grade and recovery rate of 3 ^# flocculant are above the SH930 curve, indicating that the concentrate grade and recovery rate are better than those of SH930. It can be seen that 3 ^# flocculant pair The effect of lead flotation is smaller than that of SH930. Therefore, it is better to choose 3 ^# flocculant for 3 ^# flocculant and SH930.

The lead rapid selection test also showed that when the amount of flocculant in the wastewater exceeds 2.5g/t, the flocculation phenomenon is more serious in the lead rapid selection operation, which affects the flotation and enrichment effect of lead, but if appropriate Treatment measures, such as increasing the amount of lime, DS, or brewing with clean water, can reduce the impact on the quality of lead fast concentrate and obtain test indicators close to clean water.

Fourth, the conclusion

Through a series of wastewater treatment agents DPA150, PMA-I, PHO-IV, SH930, ₃ ^# flocculant, FeCl ₃ sedimentation test and its comparison test on lead flotation, we can draw the following conclusions:

(1) In addition to the poor sedimentation effect of FeCl ₃ in the six kinds of wastewater sedimentation agents selected in this experiment, several other sedimentation effects are better, and the difference of their sedimentation effects is not obvious, and with the increase of the amount of sedimentation agent, the sedimentation effect is more good.

(II) Comparative test of lead fast selection and lead rough selection shows that 3 ^# flocculant and SH930, when the dosage is less than 5g/t, have less influence on the rough selection of lead. The four agents of PMA-I, DPA150, DPO-15 and FeCl ₃ have a great influence on lead flotation. The main influence is that with the increase of the dosage, the lead grade decreases greatly (3% to 6%), and the lead recovery rate changes. Large (more than 2%), especially when the amount of organic agent exceeds 2.5g/t, the foam color becomes lighter and contains more impurities as the amount of flocculant increases. Seriously affect product grade and recovery rate, should avoid using such sedimentation agents.

(3) The rapid selection of lead indicates that the effect of 3 ^# flocculant is better than that of SH930. The main performance is that under the same conditions, the quality and recovery rate of the selected products are higher than the other.

(IV) Through the experimental study on the wastewater sedimentation and its subsequent flotation utilization, there are many choices for the sedimentation of the wastewater from the Wankou ore dressing, but they all have a significant impact on the subsequent flotation utilization. Relatively speaking, this test Among the 6 flocculants selected, the 3 ^# flocculant has the least effect on the flotation of lead, and can be used in a small amount.