Optimization of Pretreatment Process for Lead and Zinc Flotation of Cyanide Tailings

Qingdao gold lead zinc Development Co. feedstock treated extract after gold tailings, the amount of daily treatment of 100 t of a cyanide factory, wastewater daily 300m ^3, the output of tailings about 50 t, from the incorporation of From the beginning, the company is committed to the research on the clean production technology of the comprehensive recovery of lead and zinc resources in the flotation process of cyanide tailings. After the application of this technology in industrial production, the ore dressing index is becoming more stable, and the ore dressing wastewater is reused, and the tailings are used. The use of acid and cement as an auxiliary material completely solved the environmental pollution caused by the beneficiation production, realized the clean production of the cyanide tailings beneficiation process, and achieved remarkable social and economic benefits. In recent years, with the deepening of underground mining in upstream enterprises, the nature of ore has become more and more complicated, which has led to an increase in the amount of cyanide in the process of gold extraction. The content of impurity ions in the mixed concentrate products produced by the company exceeds the standard. It has a great impact, and it is necessary to optimize the company's production technology in order to completely solve the above problems.

I. Proposal of slurry pretreatment technology

The purpose of pretreatment is mainly to solve the effect of slime, cyanide and excess flotation agent on the flotation of lead and zinc. Due to the serious muddy mud, excessive flotation agent and high cyanide concentration, it not only affects the lead and zinc grade, but also affects the lead and zinc recovery rate. Through the pretreatment of the slurry, the effects of excess flotation agent, slime and cyanide are effectively solved, the production is stabilized, and the index is improved.

Second, mixed flotation

The technical difficulty in recovering lead and zinc from cyanide tailings has been very large, especially the effects of CN ^- and its complexes, large amounts of argillaceous gangue and ultrafine galena. Based on the flotation characteristics of galena and zinc sphale in cyanide tailings, this study is based on electrochemistry, rationally and effectively controls the flotation medium, optimizes the flotation characteristics of minerals, and increases the floatability of sulfide minerals. The effective recovery of lead and zinc minerals in cyanide tailings has achieved satisfactory results.

Third, production test

(1) Pretreatment of pulp. Adding mineralization backwater to the cyanide tailings, and then adding concentrated sulfuric acid for 5 minutes. After the concentrated sulfuric acid reacts with the slurry, the activated carbon is removed for 55 minutes, and then pumped to the flotation section.

The process conditions at this stage: 1 slurry concentration 340% ~ 38%; 2 concentrated sulfuric acid dosage 5 ~ 6 kg / t; 3 activated carbon dosage 0.5 ~ 0.6kg / t; 4pH = 5 ~ 6; 5 oxidative drug removal mixing time 1h .

(2) Mixed flotation. After the pretreated ore pump into a buffer tank φ3m stirring, stirring was continued for 30 min, 1 ^# people gravity, ^# 2 dosing grooves, copper sulfate were added, isoamyl xanthate + diethyldithiocarbamate, thoroughly stirred into the slurry The flotation unit is rough-selected, and the coarse concentrate obtained by rough selection is selected three times to obtain a qualified lead-zinc mixed concentrate. After three times of sweeping the tailings, the tail of the flotation is obtained. Mine, tailings, that is, sulfur concentrate, the process conditions at this stage: 1 rough selection, pH = 5 ~ 6, copper sulfate dosage 0.5 ~ 0.8 kg / t, isoamyl yellow pharmaceutical dosage 0.4 ~ 0.5 kg / t, B Sulfur and nitrogen dosage 0.4～0.5 kg/t; 2 sweeping, pH=6.0, copper sulfate dosage 0.1～0.2 kg/t, isoamyl yellow pharmaceutical dosage 0.04～0.05kg/t, ethylsulfuric nitrogen dosage 0.04～0.05 kg /t.

(3) Reuse of tail water. The lead-zinc mixed concentrate, the filtrate after the crushing of the sulfur concentrate, the overflow water of the thickener, the washing water inside the workshop, and the ore dressing tail water are all concentrated in the tailings water storage. The library uses impermeable treatment by the action of sun exposure and atmosphere, part of the wastewater decomposition CN ^-, the organic agent directly reused, and achieved good results.

Fourth, the test results

(1) Test conditions. The test conditions are shown in Table 1.

Table 1 Test conditions

(2) Test results. The test results are shown in Table 2.

Table 2 Test results %

V. Conclusion

(1) Using the slurry pretreatment technology such as strong oxidation of concentrated sulfuric acid and adsorption of activated carbon, the mixed utilization of the lead and zinc mineral resources in the cyanide tailings is improved by using a mixed flotation process under acidic medium.

(2) Successful application of slurry pretreatment, the content of silica in lead-zinc mixed concentrate decreased from 8.5% to 5.1%, which satisfied the market demand, increased the company's product price and increased the economic benefits of the company.

(3) All ore dressing wastewater is reused to achieve zero discharge of wastewater.

(4) The final waste residue can be used as a sulfur concentrate for export, realizing the comprehensive utilization of beneficiation tailings and zero discharge of tailings, thus achieving clean production of the beneficiation process, achieving remarkable environmental and economic benefits, and handling cyanidation at home and abroad. The recovery of valuable metals from tailings has important reference and promotion value.

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