Small-scale experimental study on high oxidation rate lead-zinc sulfide ore dressing

In general, high sulfur non-ferrous metal sulphide ores easily burst into flames, the prevalence of domestic and international high-class ore useful metal oxidation degree, the nature of complex, large sorting difficult, there is no effective sorting technology, resources There are not many developments. Mining Field large, fire cassiterite - polymetallic sulphide ores large reserves, the portion of the ore containing a variety of useful metals, tin, lead, antimony, zinc, indium, abundant, high potential value. Among them, the value of cassiterite accounts for about 45%, which can be sorted by traditional methods; the combined value of lead, bismuth and zinc accounts for about 50%, but the oxidation rate is higher, reaching 10% to 40% respectively, which cannot be determined by ordinary sulphide ore method. Get the ideal sorting indicator. Effective process and pharmaceutical systems must be explored to achieve the purpose of comprehensive recycling, so that the difficult use of mineral resources can be comprehensively utilized at an early date, bringing practical economic benefits to enterprises and industries, and providing useful benefits for other fired ore sulfides. Learn from.

First, the nature of the ore

(1) Analysis of raw ore

The test integrated mineral samples were taken from mine ore. The main useful minerals of the ore are cassiterite, iron sphalerite, brittle bismuth lead, bismuth tin ore, pyrite, pyrrhotite, arsenopyrite and rare metals such as silver , indium and cadmium , and contain a small amount. The copper and bismuth , the gangue are mainly calcite and quartz , the multi-element chemical analysis results of the samples are shown in Table 1, and the mineral composition analysis is shown in Table 2.

Table 1 Results of multi-element analysis of test ore chemistry (%)

Table 2 Test results of mineral composition of raw ore (%)

(2) Characteristics of ore properties

It can be seen from the analysis of the ore that the ore has a lower tin content, and the size of the cassiterite crystal is finer, and a larger part is impregnated.

It is embedded in gangue and sulfide ore, especially in close proximity to sulfide ore. All kinds of sulfide ore are unevenly embedded with fine particles, and they are densely embedded. In addition to pyrite grinding to 0.2mm or less, other sulfide minerals need to be ground to less than 0.1mm. Dissociation. In addition, the oxidation rate of lead and zinc minerals is relatively high, the oxidation rate of zinc minerals is generally around 11%, the oxidation rate of lead and antimony minerals is 30%, and the highest is 44%, 35%%; It is of good quality and has a high content of pyrrhotite with similar properties to iron sphalerite.

Second, the test process and the pharmaceutical system

According to the nature of the ore, the ore is a complex ore of oxidized ore and sulfide ore mixed crystallized. The production practice of the same type of ore shows that the cassiterite is easy to pass the powder, and the flotation granularity of the sulphide ore exceeds 0.3 mm, so it is difficult to float. Therefore, it is suitable to grind the ore to 0.3 mm, and the particle size does not cause serious cassiterite powder. At this particle size, the comprehensive dissociation degree of cassiterite reaches 90.54%, and the comprehensive dissociation degree of lead bismuth zinc minerals reaches 85%. After the lead bismuth zinc minerals are floated, the cassiterite in the flotation tailings is treated by re-election method. The lead-bismuth minerals are separately separated from the zinc mineral flotation. This is the conventional method for the selection of cassiterite 2 polymetallic sulphide ore. Therefore, the mineral separation test process mainly considers two options: the lead-bismuth preferential flotation process and the full-floating 2-lead-zinc separation process.

Another key issue in the ore selection is the flotation recovery of heavily oxidized lead bismuth zinc minerals. Regarding the flotation recovery of lead and zinc oxide minerals, the main research directions in recent years at home and abroad are: (1) To develop selective collectors for lead-zinc ore, to achieve the purpose of sorting without or with sodium sulfide; ) Exploring the process of demineralization; (3) solving the problem of separation of zinc oxide ore from carbonate; (4) studying the selective flocculation separation process of oxidized minerals; (5) optimizing the conventional beneficiation process ^[1] . Although the research work has made certain progress, there is no substantial breakthrough, the recovery rate of ore dressing is low, and the comprehensive economic benefits are poor. The lead-zinc-zinc minerals that have been burned and oxidized in Dachang orefield have their unique characteristics, which are quite different from those of lead-zinc oxide. According to preliminary analysis, after the ore is severely oxidized, an iron oxide film is formed on the surface of the iron sphalerite, which affects the floatability of the zinc mineral. The surface of the brittle sulphur lead antimony ore is covered with lead sulfate, which dissolves the hydrophilicity in the pulp; after Pb ^{2 + is} adsorbed on the surface of the stibnite, the hydrophilicity is difficult to float ^[2] . These characteristics dictate that a unique pharmaceutical system must be explored in the trial to eliminate various factors that affect the floatability of the mineral. Therefore, in the two process tests, the activator and selective collector of lead-zinc-zinc minerals and their combination with ordinary sulfide ore flotation agents were considered.

Third, the results and analysis

(1) Priority flotation process test

The priority flotation process is simple, so the program was first considered in the test. The principle flow is: grinding 2 lead bismuth flotation 2 zinc sulphur mixed float 2 zinc sulphur separation. The particle size of the flotation feed is selected to be -0.3 mm. According to the local mineral processing experience, the experiment explored the use of butyl ammonium black or ethyl sulphide as a collector, XSQ, sodium sulphide or ammonium chloride as an activator under neutral to weak acid (pH=6-7) pulp conditions. Used alone or in combination to preferentially float lead-lead minerals. The open circuit condition test flow chart is slightly, and the best test results are shown in Table 3.

Table 3 Lead-leaf priority flotation conditions test results (%)

The test results show that the lead and antimony preferential flotation process scheme has lower grade and recovery rate of lead antimony concentrate, the better index is about 40%, and the zinc concentrate grade and recovery rate are also low, only 50%. , about 70%. Analysis of the particle size of each product shows that the coarse-lead lead-bismuth mineral of +0.1 mm in the lead-bismuth concentrate is basically not floating, and most of the lead-lead metal lost is in the floating zinc tailings, indicating that the particle size of the flotation separation is too coarse. For another reason, some lead-bismuth ore is more oxidized. In the absence of copper sulfate to participate in the activation, this part of the lead-bismuth mineral is difficult to float in the priority flotation. Explain that the priority flotation process is not suitable for the selection of the ore.

(II) Test of the complete float 2 lead and zinc separation process

The principle flow of the scheme is: grinding 2 sulfide ore full float 2 sulfide ore re-grinding 2 lead bismuth flotation 2 zinc sulfur separation. The sulphide ore is fully floated and the ore is selected to have a particle size of -0.3 mm. Lead-separated and zinc-separated flotation feeds have a particle size of -0.1 mm.

The program has carried out the comparison test of the full float operation agent, the open circuit test of the full float 2 separation process and the closed circuit test.

1. Comparative test of full float operation

The experiment mainly explored the activation effects of ammonia chloride, sodium sulfide, XSQ and X activator on the oxidized minerals of lead-zinc-zinc oxide which were burned alone or in combination. The flow is shown in Figure 1.

Figure 1 Flow chart of comparison test of full float operation

The results of comparative experiments show that the activation effect of ammonium chloride and X activator on lead-zinc-zinc minerals is poor, and the activation effect of sodium sulfide is second, and XSQ is the best. It has been found that sodium sulfide easily reacts with free copper and lead metal particles in the slurry to form sulfide precipitates of copper and lead, and relatively increases the amount of chemicals used when copper sulfate, XSQ and sodium sulfide are used in combination. In addition, in the case where the other chemical conditions are substantially the same, the amount of XSQ can be relatively reduced as the amount of sulfuric acid in the full float and sweeping operation increases.

Test conditions (g·t ^{- 1} ): sulfuric acid: 3000; copper sulfate: 450; xanthate: 512; 2 ^#油: 147.

The results of partial drug comparison test are shown in Table 4.

Table 4 Comparison test results of total floating operation agent (%)

2, full float 2 lead and zinc separation process open circuit test

In the results of the comparison test of the full floatation agent, XSQ was selected as the main activator of lead oxide antimony ore, and sulfuric acid was used as an auxiliary cleaning and activator. The experiment carried out a detailed exploration of the chemical system of lead-bismuth flotation operation. It has carried out comparative tests on sulfide ore inhibitors: sodium cyanide, zinc sulfate, sodium sulfide, sodium humate and lime. In addition, it also explored B. Selective recovery of lead and antimony by sulfur and nitrogen. The comparative results of the flow test are shown in Table 5.

Table 5 Test results of preferred conditions for lead and zinc separation (%)

The test results show that the lead-bismuth flotation operation is under weak alkaline pulp conditions (pH=8 or so), and only conventional cyanide + zinc sulfate is used as an inhibitor, and a small amount of collector, ethylsulfide, is used. With the second fine sweeping operation, high-quality lead-bismuth concentrate can be obtained. The Pb+Sb metal content is above 45%, and the lead metal recovery rate is about 58%. The zinc flotation operation uses lime as an inhibitor of pyrite and pyrrhotite, activates the suppressed zinc mineral with copper sulfate, and uses a small amount of xanthate as a collector. After a coarse and fine sweep operation, it can be obtained. Zinc minerals with a zinc content of 48% and a recovery rate of 73% or more are relatively good.

(3) Small closed circuit test

Comprehensive comparison of the results of the small open circuit test of the full float 2 lead and zinc separation process and the lead bismuth preferential flotation process, the selection index of the full float 2 lead and zinc separation process is better, so the small closed circuit test only uses this process plan. Compared with the open circuit test, the closed-circuit test process added a lead selection and a zinc selection operation respectively to eliminate the adverse effects of the return of the middle ore return on the quality of lead and zinc concentrate. The specific test procedure is shown in Figure 2. The results of the closed circuit test are shown in Table 6.

Figure 2 closed circuit test process

Table 6 Closed-circuit test results P%

Fourth, the conclusion

1. Dachang orefield fired cassiterite 2 polymetallic sulphide ore, lead bismuth and zinc minerals are mainly oxidized on the surface, and the surface oxidized covering seriously affects the floatability of minerals.

2. The combined action of sulfuric acid and XSQ can remove a variety of coverings of severe oxidation of mineral surfaces, making lead-zinc-zinc minerals relatively easy to float.

3. Ethyl sulfide has a good effect on the oxidized lead and bismuth minerals.

4, using the full float 2 lead and zinc separation process, using XSQ and ethyl sulfide nitrogen as the activator and selective collector of lead oxide antimony ore, can obtain a better selection index: lead ore concentrate grade reached 44.95% The recovery rate is 60.92%; the zinc concentrate grade reaches 46.37%, the recovery rate is 81.17%; the recovery rate of tin metal in the whole flotation tailings reaches 89.16%.

references:

[1] Fang Qixue. Discussion on the basic ideas of extracting lead and zinc resources in western China[J]. Mining and Metallurgy, 2002, 75-78 (supplement): 200.

[2] Hu Weibai. Flotation (revised edition) [M]. Changsha: Central South University of Technology.

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