Method for flotation of lead concentrate from lead-zinc sulfide ore

Abstract

The invention relates to the technical field of lead-zinc ore flotation, in particular to a method for flotation of lead concentrate from lead-zinc sulfide ore. In order to solve the problem of low dissociation degree of lead and zinc monomers in the first-time concentrated tailings of lead, the first-time concentrated tailings of lead and first-stage grinding and grading overflow ore pulp are mixed and then subjected to second-stage grinding and grading treatment, ore over-grinding is avoided, meanwhile, coarse-fraction returned sand and settled sand are returned to a ball mill to be ground again, and the separation degree of lead and zinc monomers in the first-time concentrated tailings of lead is improved. Therefore, the lead metal is prevented from circulating back and forth in lead roughing and lead first-time concentration in a middling mode, and lead and zinc are prevented from being gradually accumulated in the lead first-time concentration process and worsening the flotation process. After countercurrent grading and regrinding of the first-time lead concentrate tailings, coarse-grained minerals in the first-time lead concentrate tailings are ground to fine-grained minerals, lead-zinc intergrowth circulating back and forth in the lead roughing and first-time lead concentration processes is reduced, the concentration of the first-time lead concentrate tailings is reduced, the dissociation degree of lead and zinc monomers is improved, and the lead-containing grade of lead concentrate is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lead-zinc ore flotation, and particularly relates to a method for floating lead concentrate from a lead-zinc sulfide ore. BACKGROUND

[0002] The lead-zinc sulfide ore accounts for 90% of the total lead-zinc reserves in China, and is the main source of smelting lead metal at present. At present, the flotation method is usually adopted to separate lead and zinc in the lead-zinc sulfide ore. In the flotation process, the sequential flotation process of suppressing zinc and floating lead is adopted, and the lead in the lead-zinc ore is floated through the flotation process of once lead roughing, twice lead scavenging and thrice lead cleaning.

[0003] However, the inventors have found in the process of conceiving and implementing the present application that, on the one hand, with the gradual depletion of mineral resources, the proportion of residual ores gradually increases, the content of sulfur, iron and impurities in the raw ore increases, and the grindability of the raw ore decreases. The one-stage grinding classification treatment is adopted for the grinding classification, the classification effect is poor, and the over-grounding and under-grounding phenomena exist in the overflow product of the grinding, which causes the low concentration of the ore slurry after the classification overflow, and thus the low degree of liberation of lead and zinc.

[0004] Therefore, in view of the low degree of liberation of lead and zinc in the first lead cleaning tailings, a method for floating lead concentrate from a lead-zinc sulfide ore is needed to improve the degree of liberation of lead and zinc in the first lead cleaning tailings.

[0005] The above content is only used to assist in understanding the technical solutions of the present application and does not mean that the above content is prior art. SUMMARY

[0006] The main purpose of the present application is to provide a method for floating lead concentrate from a lead-zinc sulfide ore, which aims to solve the problem of how to improve the degree of liberation of lead and zinc in the first lead cleaning tailings.

[0007] In order to achieve the above-mentioned purpose, the present application provides a method for floating lead concentrate from a lead-zinc sulfide ore, which comprises the following steps: S1: grinding the raw ore and then performing one-stage grinding classification treatment to obtain one-stage grinding classification overflow slurry and returned sand; S2: performing two-stage grinding classification treatment on the one-stage grinding classification overflow slurry to obtain two-stage grinding classification overflow slurry and settled sand; S3: performing roughing treatment on the two-stage grinding classification overflow slurry to obtain lead roughing concentrate and lead roughing tailings; S4: twice scavenging of the lead roughing tailings to obtain lead tailings; S5: first lead cleaning of the lead roughing concentrate to obtain first lead cleaning tailings and first lead cleaning concentrate; S6: returning the first lead cleaning tailings to step S2 to mix with the first stage grinding classification overflow slurry for second stage grinding classification treatment; S7: twice cleaning of the first lead cleaning concentrate to obtain lead concentrate.

[0008] Optionally, the sand and returned sand are combined and returned to step S1 to mix with the raw ore for grinding.

[0009] Optionally, the specific steps of S4 include: first lead scavenging of the lead roughing tailings to obtain first lead scavenging concentrate and first lead scavenging tailings; second lead scavenging of the first lead scavenging tailings to obtain second lead scavenging concentrate and lead tailings.

[0010] Optionally, the specific steps of S7 include: second lead cleaning of the first lead cleaning tailings to obtain second lead cleaning concentrate and second lead cleaning tailings; third lead cleaning of the second lead cleaning tailings to obtain lead concentrate and third lead cleaning tailings.

[0011] Optionally, the specific steps of S1 include: grinding of the raw ore by a ball mill and first stage grinding classification treatment by a spiral classifier to obtain first stage grinding classification overflow slurry and returned sand.

[0012] Optionally, the specific steps of S2 include: second stage grinding classification treatment of the first stage grinding classification overflow slurry by a second stage hydrocyclone to obtain second stage grinding classification overflow slurry and sand.

[0013] In another aspect, the application provides use of the lead tailings obtained by the above method in zinc flotation.

[0014] Principle of the application: The application utilizes the existing production process, in order to solve the problem of low lead and zinc monomer dissociation degree in the lead first selection tailings, the lead first selection tailings and the first stage grinding classification overflow slurry are mixed and then subjected to second stage grinding classification treatment, so that the ore is prevented from being overground, the second stage grinding classification overflow slurry is subjected to lead roughing, and the coarse grain level return sand and the sand return are returned to the ball mill for regrinding, so that the lead metal in the form of middlings is prevented from circulating back and forth in the lead roughing and the lead first selection, the lead and zinc are prevented from gradually accumulating in the lead first selection process, and the flotation process is prevented from deteriorating. Through the countercurrent classification regrinding of the lead first selection tailings, the coarse grain level minerals in the lead first selection tailings are ground to fine grain level, the lead and zinc intergrowth circulating back and forth in the lead roughing and the lead first selection is reduced, the concentration of the lead first selection tailings is reduced, the lead and zinc monomer dissociation degree is improved, and the lead content of the lead concentrate is improved.

[0015] The embodiment of the application provides a method for floating lead concentrate from a lead-zinc sulfide ore, and at least has the following beneficial effects: 1. The method for floating lead concentrate from a lead-zinc sulfide ore provided by the application is used for solving the problem of low lead and zinc monomer dissociation degree in the lead first selection tailings in the flotation process, the grinding classification process is optimized from a one-stage grinding classification process to a two-stage grinding classification process, the lead first selection tailings and the first stage grinding classification overflow slurry are mixed and then subjected to two-stage grinding classification treatment, the two-stage grinding classification overflow slurry is subjected to lead roughing, and the coarse grain level return sand and the sand return in the one-stage and two-stage grinding classification treatment are returned to the ball mill for regrinding. The method not only improves the grinding fineness, but also improves the lead and zinc monomer dissociation degree in the lead first selection tailings. 2. The method improves the lead and zinc monomer dissociation degree in the lead first selection tailings, reduces the circulating amount of lead and zinc intergrowth in each operation, reduces the accumulation of lead first selection tailings intergrowth, reduces the concentration of the lead first selection tailings, improves the ore selectivity, and improves the lead content of the lead concentrate. 3. The method improves the ore selectivity, improves the lead content of the lead concentrate, reduces the lead content of the zinc concentrate, improves the lead ore recovery rate, reduces the loss of zinc metal in the lead concentrate, and improves the recovery rate of the zinc ore. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a process flow diagram of the application.

[0017] Figure 2 It is a process flow diagram of Comparative Example 1.

[0018] Figure 3 It is a grinding classification process flow diagram in Example 3.

[0019] Figure 4 It is a lead concentrate grade statistical diagram before and after the optimization of the grinding classification process in Example 3.

[0020] Figure 5 Optimized process flow chart for lead first cleaning tailings of example 3.

[0021] Figure 6 Lead concentrate grade statistics chart in 2023.

[0022] Figure 7 Lead and zinc ore recovery rate statistics chart in 2023.

[0023] Figure 8 Lead concentrate grade comparison chart in example 4.

[0024] Figure 9 Zinc concentrate grade comparison chart in example 4.

[0025] Figure 10 Lead ore recovery rate comparison chart in example 4.

[0026] Figure 11 Zinc ore recovery rate comparison chart in example 4.

[0027] Figure 12 Single liberation degree analysis chart of lead first cleaning tailings sample before optimization.

[0028] Figure 13 Main sulfide mineral liberation degree statistics result chart of +200 mesh sample of lead first cleaning tailings after optimization.

[0029] Figure 14 Main sulfide mineral liberation degree statistics result chart of -200 mesh to +320 mesh sample of lead first cleaning tailings after optimization.

[0030] Figure 15 Main sulfide mineral liberation degree statistics result chart of -320 mesh to +500 mesh sample of lead first cleaning tailings after optimization.

[0031] Figure 16 Main sulfide mineral liberation degree statistics result chart of -500 mesh sample of lead first cleaning tailings after optimization.

[0032] The implementation, functional characteristics and advantages of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION

[0033] For a better understanding of the above technical solutions, the exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure can be more thoroughly understood and the scope of the present disclosure can be fully conveyed to those skilled in the art.

[0034] Based on the above description, an embodiment of a method for floating lead concentrate from a lead-zinc sulfide ore is proposed.

[0035] Embodiment 1 A certain concentrator in Yunnan province floats lead concentrate from a lead-zinc sulfide ore. The grinding and classification process adopts a "two-stage grinding and classification process". A hydrocyclone is installed after the first-stage classification screw classifier. The overflow slurry of the screw classifier is fed into the hydrocyclone for two-stage grinding and classification. The sand of the two-stage grinding and classification is combined with the sand returned from the first-stage grinding and classification and then returned to the ball mill for regrinding. The flotation process adopts a sequential flotation process of zinc depression and lead flotation. The lead and zinc flotation both adopts a "one roughing, two scavenging and three cleaning" flotation process. The process flow chart is shown in FIG. 1. The specific steps include the following steps: Figure 1 S1: The raw ore is ground by a ball mill and then subjected to first-stage grinding and classification to obtain first-stage grinding and classification overflow slurry and sand returned from the first stage; The first-stage grinding and classification device is a screw classifier; S2: The first-stage grinding and classification overflow slurry is subjected to two-stage grinding and classification to obtain two-stage grinding and classification overflow slurry and sand; The sand is combined with the sand returned from the first stage and then returned to the ball mill for regrinding; S3: The two-stage grinding and classification overflow slurry is subjected to lead roughing; Specific steps include: the two-stage grinding and classification slurry is pumped into a flotation machine by a pump, zinc depressant and lead collector are added, the reagents and the slurry are fully mixed by stirring, the impeller of the flotation machine rotates to produce negative pressure to suck in air, form bubbles, the bubbles collide with lead mineral particles and are adsorbed to form a lead-rich froth layer, the froth on the surface of the flotation machine is scraped out by a mechanical scraper to form a lead roughing concentrate, and the inhibited marmatite, pyrite and gangue are difficult to attach bubbles due to their hydrophilic surface, and flow downward with the slurry to form a lead roughing tailing; The zinc depressant is zinc sulfate and sodium sulfite, and the lead collector is No. 25 black drug and ethyl xanthate; S4: The lead roughing tailing is subjected to two times of scavenging to obtain a lead tailing; Specific steps include: No. 25 black drug and ethyl xanthate are added to the lead roughing tailing for the first time of lead scavenging to obtain a lead first-time scavenging concentrate and a lead first-time scavenging tailing;​ The lead first sweep election concentrate is returned to step S3 for lead roughing treatment; The lead first sweep election concentrate is returned to step S3 for lead roughing treatment; The lead first sweep election concentrate is returned to step S3 for lead roughing treatment; S5: The lead roughing concentrate is subjected to lead first cleaning treatment to obtain lead first cleaning tailings and lead first cleaning concentrate; Specific steps include: the lead roughing concentrate slurry is pumped into a flotation machine by a pump, zinc sulfate and sodium sulfite are added, and the reagents are fully mixed with the slurry by stirring. The impeller of the flotation machine rotates to produce negative pressure to suck in air, forming bubbles. The bubbles collide with and adsorb lead mineral particles to form a foam layer rich in lead. The foam on the surface of the flotation machine is scraped off by a mechanical scraper to form the lead first cleaning concentrate. The inhibited sphalerite, pyrite and gangue, which are difficult to attach bubbles due to their hydrophilic surfaces, flow downward with the slurry to form the lead first cleaning tailings. S6: The lead first cleaning tailings are returned to step S2 to mix with the one-stage grinding classification overflow slurry for two-stage grinding classification treatment; S7: The lead first cleaning concentrate is subjected to two cleaning treatments to obtain lead concentrate; Specific steps include: The lead first cleaning concentrate is added with zinc sulfate and sodium sulfite for lead second cleaning to obtain lead second cleaning concentrate and lead second cleaning tailings; The lead second cleaning tailings are returned to the lead first cleaning for lead first cleaning treatment; The lead second cleaning concentrate is added with zinc sulfate and sodium sulfite for lead third cleaning to obtain lead concentrate and lead third cleaning tailings; The lead third cleaning tailings are returned to the lead second cleaning for lead second cleaning treatment.

[0036] Comparative Example 1 The difference between this comparative example and Example 1 is that the two-stage grinding classification treatment process in Example 1 is changed to one-stage grinding classification treatment, i.e., the raw ore is ground by a ball mill and then subjected to grinding classification treatment to obtain grinding classification overflow slurry. The grinding classification overflow slurry is directly subjected to lead roughing subsequently. The lead first cleaning tailings are returned to step S3 for lead roughing treatment.

[0037] The other procedures remain unchanged; the process flow is shown in Figure 2 .

[0038] Example 2 On the basis of embodiment 1, the lead tailings are subjected to zinc concentrate flotation, and the zinc flotation adopts the flotation process of "one roughing, two scavenging and three cleaning", and finally the zinc concentrate is obtained.

[0039] Comparative example 2 On the basis of comparative example 1, the lead tailings are subjected to zinc concentrate flotation, and the zinc flotation adopts the flotation process of "one roughing, two scavenging and three cleaning", and finally the zinc concentrate is obtained.

[0040] Embodiment 3 I. This embodiment will illustrate the process of optimization before and after, including: S1, before optimization: adopt one-stage closed-circuit grinding process, and after grinding, the lead flotation adopts the flotation process of "one roughing, two scavenging and three cleaning" to float the lead, and the lead concentrate and lead tailings are obtained; the lead tailings are subjected to zinc flotation, and the flotation adopts the flotation process of "one roughing, two scavenging and three cleaning", and finally the zinc concentrate is obtained; see comparative example 2 for detailed process; S2, optimization of grinding classification process: on the basis of S1, only the grinding process is optimized, and the one-stage closed-circuit grinding process is optimized to two-stage grinding classification treatment, and other conditions are exactly the same as S1; S3, after optimization: on the basis of S1, first, the one-stage closed-circuit grinding process is optimized to two-stage grinding classification treatment, and then the tailings of the first lead cleaning are returned to the two-stage grinding classification treatment for re-classification treatment, and other conditions are exactly the same as S1; see embodiment 2 for detailed process; In this embodiment, by comparing the different flotation processes of comparative example 2 and embodiment 2, the influence of different processes before and after optimization on the lead and zinc monomer dissociation degree in the tailings of the first lead cleaning is studied; at the same time, the influence of the improved process on the lead grade of the lead concentrate is studied.

[0041] II. Before optimization (comparative example 2): Table 1 Product grade and concentration statistics table The sampling points in table 1 are described in detail: Raw ore: classification overflow (spiral classifier overflow port); Lead roughing: froth tank (lead roughing froth tank 1-5 froth scraping point, lead roughing concentrate sampling point), intermediate tank (lead roughing tailings sampling point); First lead scavenging: froth tank (lead first scavenging froth tank 1-4 froth scraping point, lead first scavenging concentrate sampling point), intermediate tank (lead first scavenging tailings sampling point); Second lead scavenging: froth tank (lead second scavenging froth tank 1-3 froth scraping point, lead second scavenging concentrate sampling point), intermediate tank (lead second scavenging tailings sampling point); Lead first cleaning: froth tank (lead first cleaning flotation tank 1-5 froth scraping point, lead first cleaning concentrate sampling point), intermediate tank (lead first cleaning tailings sampling point); Lead second cleaning: froth tank (lead second cleaning flotation tank 1-3 froth scraping point, lead second cleaning concentrate sampling point), intermediate tank (lead second cleaning tailings sampling point); Lead third cleaning: froth tank (lead third cleaning flotation tank 1-2 froth scraping point, lead third cleaning concentrate sampling point), intermediate tank (lead third cleaning tailings sampling point); From Table 1, the concentration and mineral grade enrichment of each operation in the flotation process can be seen: in the lead series, the concentration of the classified overflow of the run-of-mine is relatively low, only 29.96% in December 2021 and 30.96% in April 2022; the tailings concentrations of the lead first cleaning, lead second cleaning and lead third cleaning are relatively high, with the tailings concentrations of the lead first cleaning, lead second cleaning and lead third cleaning being 60.41%, 72.70% and 55.96% respectively in December 2021, and 63.96%, 61.89% and 40.87% respectively in April 2022; the tailings concentrations of the lead first cleaning, lead second cleaning and lead third cleaning are 59.86%, 66.07% and 67.46% respectively in December 2021, and 50.21%, 60.00% and 61.43% respectively in April 2022; the lead concentrate obtained from the lead third cleaning contains only 59.31%-62.39% lead; The enrichment ratio calculation formula is: enrichment ratio = concentrate lead grade / run-of-mine lead grade; Through calculation, the enrichment ratio of the lead first cleaning concentrate lead grade to the lead roughing concentrate lead grade was 48.70 / 39.92 = 1.22 in December 2021, and the enrichment ratio of the lead first cleaning concentrate lead grade to the lead roughing concentrate lead grade was 24.30 / 14.44 = 1.68 in April 2022, which was relatively low and was not conducive to the improvement of the lead concentrate grade.

[0042] Table 2 Product particle size proportion and metal distribution rate of each operation In Table 2, the sampling points are: Lead roughing concentrate: lead roughing concentrate scraping point; Lead concentrate: lead third cleaning froth scraping point.

[0043] From Table 2, the particle size distribution and metal distribution of the lead roughing concentrate and the lead first-stage concentration tailings are close. The content of the +200 to +300 mesh particle size of the lead roughing concentrate accounts for 73.38%, and the lead metal distribution rate in this particle size is 81.72%. The content of the +200 to +300 mesh particle size of the lead first-stage concentration tailings accounts for 69.72%, and the lead metal distribution rate in this particle size is 82.1%. The content of the +200 to +300 mesh particle size of the lead concentrate is 15.31%, and the lead metal distribution rate is 14.22%. The content of the -500 mesh particle size accounts for 66.18%, and the metal distribution rate is 67.26%. The fine particle size is dominant, so the lead metal recovery rate in the +200 to +300 mesh particle size is low.

[0044] Further analysis of the +200 mesh particle size shows that the content of the +200 mesh particle size of the lead roughing concentrate accounts for 21.34%, and the lead metal distribution rate is 26.93%. The content of the +200 mesh particle size of the lead first-stage concentration tailings accounts for 15.33%, and the lead metal distribution rate in this particle size is 19.61%. The content of the +200 mesh particle size of the lead concentrate is 0, indicating that the lead metal in the +200 mesh particle size is not selected into the lead concentrate. The content of the +300 mesh particle size of the lead first-stage concentration tailings accounts for 53.79%, and the lead metal distribution rate in this particle size is 62.94%. The content of the +300 mesh particle size of the lead concentrate is 15.31%, and the lead metal distribution rate in this particle size is 14.22%, indicating that most of the lead metal in the +300 mesh particle size is not selected into the lead concentrate. Therefore, in combination with the analysis of the lead roughing concentrate and the lead first-stage concentration tailings, the lead metal in the +200 to +300 mesh particle size in the lead flotation process is circulated in the form of middlings between the roughing and the lead first-stage concentration tailings, resulting in high concentration, coarse particle size, large circulation amount, and poor separation effect of the lead first-stage concentration tailings.

[0045] Table 3: Statistical results of the dissociation degree of main sulfide minerals of the lead first-stage concentration tailings before optimization Through comprehensive analysis of Table 1, Table 2, and Table 3, and Figure 12 According to the analysis diagram of the single dissociation degree of the lead first-stage concentration tailings before optimization, the parameters before optimization are as follows: the lead content of the lead roughing concentrate is 24.73%, the zinc content is 22.32%, the content of the -500 mesh particle size of the lead roughing concentrate accounts for 16.46%, the content of the -500 mesh particle size of the lead first-stage concentration tailings accounts for 16.53%, the concentration of the lead first-stage concentration tailings is >50%, the lead single dissociation degree of the lead first-stage concentration tailings is 46.87%, and the zinc single dissociation degree is 59.97%. The concentration of the lead first-stage concentration tailings is high, and the single dissociation degree is low. Therefore, it is necessary to further study the lead first-stage concentration tailings.

[0046] III. Optimization of the grinding and classification process In March 2023, the grinding and classification process was optimized from "one-stage grinding and classification process" to "two-stage grinding and classification process". That is, a hydrocyclone is installed after the first-stage classification (classifier), and the overflow of the classifier enters the hydrocyclone for two-stage classification. The sediment of the two-stage classification is combined with the returned sand of the first-stage classification and returned to the ball mill for regrinding. The specific process diagram is shown in Figure 3 ; After the process optimization, the lead content of the lead concentrate was significantly improved. The specific data is shown in Table 4, Figure 4 : Table 4 Statistics of beneficiation indexes before and after industrial test As shown in Table 4, Figure 4 the lead content of the lead concentrate in March 2023 was 64.00%, and the mutual zinc content was 8.74%. Compared with the cumulative value from January to February, the lead content increased by 1.78 percentage points, and the mutual zinc content decreased by 0.2 percentage points.

[0047] Four, after optimization: lead first selection tailings pre-classification regrinding and reselection process (Example 2); In view of the problems of high concentration, coarse particle size, large circulation amount, and poor separation effect of lead roughing and lead first selection tailings in the lead beneficiation process, the lead sulfide local process was optimized in April 2023, i.e. the lead first selection tailings are pumped to the first-stage classification overflow buffer tank by a slurry pump, mixed with the first-stage classification overflow slurry, and then enter the hydrocyclone for two-stage classification. The overflow of the two-stage classification enters the lead flotation system, and the classification return sand returns to the ball mill for regrinding. The specific process flow is shown in Figure 5 ; After the optimization of the sulfur process, the content of fine particles in the main products of each operation of the lead series increased significantly. The particle size ratio, metal distribution, and grade of the main products before and after the process optimization are shown in Table 5: Table 5 Particle size ratio and metal distribution rate of main products after process optimization As shown in Table 5, after the process optimization, the +200 mesh content of the lead roughing was only 1.21%, which was reduced by 20.13 percentage points compared with before the optimization, and the -500 mesh content was increased by 59.71 percentage points. The -200 mesh content of the lead first selection tailings was 0, and the -500 mesh content was increased by 58.66 percentage points compared with before the optimization. The -500 mesh content of the lead concentrate was increased by 23.12 percentage points compared with before the optimization.

[0048] Table 6 Product grade statistics before and after process optimization From Table 6, it can be seen that, from the comparison of process optimization before and after the process investigation data, the concentration of the first lead cleaning tailings (intermediate box tailings) is reduced from 49% to 21.13%; compared with the lead grade of 14.44% of the lead rough concentrate in April 2022, before process optimization, the enrichment ratio of the lead grade of the first lead cleaning concentrate to the lead grade of the lead rough concentrate is 29.44 / 14.44=2.04, and after process optimization, the enrichment ratio of the lead grade of the first lead cleaning concentrate to the lead grade of the lead rough concentrate is 33.05 / 14.44=2.29, which is obviously improved, indicating that the separation effect of the first lead cleaning is improved, and the lead content of the lead concentrate is increased to 66.18%.

[0049] Table 7 Statistics results of main sulfide mineral dissociation degree of the first lead cleaning tailings after optimization From Tables 5, 6, 7 and Figures 13-16 It can be seen that after optimization: the lead content of the lead rough concentrate is 20.46%, the zinc content is 18.77%, the content of the -500 mesh particle size of the lead rough concentrate is increased to 76.17%, the content of the -500 mesh particle size of the first lead cleaning tailings is increased to 75.19%, the concentration of the first lead cleaning tailings is reduced to below 30%, the lead monomer dissociation degree of the first lead cleaning tailings is increased to 67.06%, and the zinc monomer dissociation degree is increased to 78.8%. The concentration of the first lead cleaning tailings reaches the flotation requirement, and the monomer dissociation degree is obviously improved.

[0050] In summary, before optimization: the lead monomer dissociation degree of the first lead cleaning tailings is 46.87%, and the zinc monomer dissociation degree is 59.97%. The concentration of the first lead cleaning tailings is high, and the monomer dissociation degree is low. After optimization: the concentration of the first lead cleaning tailings is reduced to below 30%, the lead monomer dissociation degree of the first lead cleaning tailings is increased to 67.06%, and the zinc monomer dissociation degree is increased to 78.8%. It can be seen that by optimizing the grinding and classification process from “one-stage grinding and classification process” to “two-stage grinding and classification process”, and by pre-classifying and then grinding and selecting the first lead cleaning tailings, the lead and zinc monomer dissociation degrees in the first lead cleaning tailings can be improved; and the circulation amount of lead-zinc intergrowths in each operation can be reduced, the intergrowth accumulation in the first lead cleaning tailings can be reduced, thereby reducing the concentration of the first lead cleaning tailings, and increasing the lead content of the lead concentrate to more than 66%.

[0051] Example 4 In this example, the effects of different flotation processes before and after process optimization in Example 3 on the lead content of the lead concentrate, the lead content of the zinc concentrate, the lead ore recovery rate, and the zinc ore recovery rate are studied.

[0052] After the lead first cleaning tailings realize pre-classification, regrinding and re-concentration, the problems of coarse particle size, high concentration, excessive accumulation of intergrowth and poor separation effect of lead first cleaning tailings are solved. From the flotation phenomenon, the problems of fine and hardening of lead roughing and lead first cleaning flotation froth are improved, and the stability of flotation operation is obviously improved. Ultimately, the beneficiation technical index makes a breakthrough progress, and the specific completion situation is shown in Table 8, Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 : Table 8 Statistics table of lead sulfide beneficiation index in 2023 Note: The lead first cleaning tailings process optimization before February 2023, except for the lead content of lead concentrate, other beneficiation indexes are the optimal index, so the index in February is selected for comparison; The lead content of lead concentrate is compared with the optimal value in March.

[0053] From Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 It can be seen that after the lead first cleaning tailings realize pre-classification, regrinding and re-concentration, the lead content of lead concentrate and the lead and zinc beneficiation recovery rate all show an upward trend.

[0054] In summary, after the process optimization, the lead content of lead concentrate is increased to 66.58%, which is increased by 2.58 percentage points compared with before optimization; the lead content of zinc concentrate is reduced to 1.6%, which is reduced by 0.21 percentage points compared with before optimization; the lead beneficiation recovery rate is increased to 88.84%, which is increased by 0.82 percentage points compared with before optimization; the lead concentrate quality is improved, the loss of zinc metal in lead concentrate is reduced, thereby improving the zinc beneficiation recovery rate, the zinc beneficiation recovery rate is increased to 91.42%, which is increased by 0.82 percentage points compared with before optimization. Therefore, with the increase of the lead content of lead concentrate, the lead content of zinc concentrate is reduced, so that the lead recovery rate is increased; after the lead content of lead concentrate is increased, the loss of zinc metal in lead concentrate is reduced, thereby improving the zinc beneficiation recovery rate.

[0055] It should be noted that although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0056] Obviously, many modifications and variations of the present application are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims and their equivalents, the application can be practiced otherwise than as specifically described.

Claims

1. A method of floating a lead concentrate from a lead-zinc sulphide ore, characterised in that, The method comprises the following steps: S1: after grinding the raw ore, a first-stage grinding classification treatment is performed to obtain a first-stage grinding classification overflow slurry and returned sand; S2: the first-stage grinding classification overflow slurry is subjected to a second-stage grinding classification treatment to obtain a second-stage grinding classification overflow slurry and settled sand; S3: the second-stage grinding classification overflow slurry is subjected to a lead roughing treatment to obtain a lead roughing concentrate and a lead roughing tailing; S4: the lead roughing tailing is subjected to two times of scavenging to obtain a lead tailing; S5: the lead roughing concentrate is subjected to a first-stage lead cleaning treatment to obtain a first-stage lead cleaning tailing and a first-stage lead cleaning concentrate; S6: the first-stage lead cleaning tailing is returned to step S2 to be mixed with the first-stage grinding classification overflow slurry and subjected to a second-stage grinding classification treatment; S7: the first-stage lead cleaning concentrate is subjected to two times of cleaning treatment to obtain a lead concentrate.

2. The method of claim 1, wherein, The settled sand and the returned sand are combined and returned to step S1 to be mixed with the raw ore for grinding.

3. The method of claim 1, wherein, The specific steps of S4 comprise: The lead roughing tailing is subjected to a first-stage lead scavenging to obtain a first-stage lead scavenging concentrate and a first-stage lead scavenging tailing; the first-stage lead scavenging tailing is subjected to a second-stage lead scavenging to obtain a second-stage lead scavenging concentrate and a lead tailing.

4. The method of claim 1, wherein, The specific steps of S7 comprise: The first-stage lead cleaning tailing is subjected to a second-stage lead cleaning to obtain a second-stage lead cleaning concentrate and a second-stage lead cleaning tailing; the second-stage lead cleaning tailing is subjected to a third-stage lead cleaning to obtain a lead concentrate and a third-stage lead cleaning tailing.

5. The method of claim 1, wherein, The specific steps of S1 comprise: After the raw ore is ground by a ball mill, a first-stage grinding spiral classifier classification treatment is performed to obtain a first-stage grinding classification overflow slurry and returned sand.

6. The method of claim 1, wherein, The specific steps of S2 comprise: The first-stage grinding classification overflow slurry is subjected to a second-stage hydrocyclone grinding classification treatment to obtain a second-stage grinding classification overflow slurry and settled sand.

7. Application of a lead tailing obtained by the method according to any one of claims 1-6 in zinc flotation.

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