A method for beneficiation of a complex disseminated high-sulfur lead-zinc sulfide ore

Abstract

The application discloses a beneficiation method for complexly-embedded high-sulfur-content lead-zinc sulfide ore, which comprises one-stage rough separation, three-stage cleaning and three-stage scavenging; a zinc flotation operation comprises one-stage rough separation, three-stage cleaning and three-stage scavenging; a sulfur flotation operation comprises one-stage rough separation, one-stage cleaning and one-stage scavenging; a sulfur concentrate dezincing operation comprises one-stage rough separation, one-stage cleaning and one-stage scavenging, calcium oxide is added in the one-stage cleaning process, a zinc collecting agent is added in the one-stage scavenging process, and tailings after the one-stage cleaning and concentrate after the one-stage scavenging are returned to the one-stage rough separation of the sulfur concentrate dezincing operation. The column machine is combined to improve the recovery rate of useful minerals, the flotation column is used for scavenging to improve the recovery rate of fine particles, the sulfur concentrate is subjected to the dezincing operation, and the dezincing product is returned to the zinc rough separation operation, so that the recovery rate of zinc minerals is improved, and through the column machine combined with the middling regrinding mode, the recovery rates of lead and zinc in the complexly-embedded high-sulfur-content lead-zinc sulfide ore are improved.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, specifically to a mineral processing method for complexly disseminated high-sulfur-content lead-zinc sulfide ores. Background Technology

[0002] The complex intermingling relationships among sulfide minerals such as galena, sphalerite, and pyrite in high-sulfur sulfide lead-zinc ores make liberation difficult. When galena and sphalerite are used as target minerals, their own intermingling particle size is extremely uneven, which makes it very difficult to determine the liberation particle size, resulting in problems such as over-grinding and insufficient liberation. This leads to high metal content in the later products, large metal loss during the separation process, and low lead-zinc recovery rate.

[0003] Existing beneficiation processes for high-sulfur-content lead-zinc sulfide ores include sequential preferential flotation of lead, zinc, and sulfur; lead flotation followed by zinc-sulfur mixed flotation and separation; and mixed flotation followed by separation of lead, zinc, and sulfur. For cases with uneven or fine-grained dissemination, current technologies generally employ methods such as staged grinding and middlings regrinding. However, these methods have the disadvantage of easily losing finely dissociated sulfide minerals and zinc sulfide minerals closely associated with pyrite. Summary of the Invention

[0004] To address the problems in the prior art, the present invention provides a beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ores, comprising: lead flotation, zinc flotation, sulfur flotation, and dezincification of sulfur concentrate;

[0005] The lead flotation operation includes: sequentially adding calcium oxide, zinc sulfate, and black reagent to the slurry after grinding the raw ore for lead sulfide flotation; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging; using flotation columns for scavenging to improve the recovery of fine, over-ground particles; sequentially adding calcium oxide during the third-stage cleaning and black reagent during the third-stage scavenging; mixing the tailings from the first cleaning and the concentrate from the first scavenging, re-grinding them, and returning them to the raw ore slurry before the first-stage roughing; re-grinding the middlings to further improve the lead recovery rate in the complex, disseminated, high-sulfur-content lead-zinc sulfide ore;

[0006] The zinc flotation operation includes: adding copper sulfate, lime, and zinc collector sequentially to the tailings slurry after the third stage scavenging in the lead flotation operation for zinc sulfide flotation; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging; during the third-stage cleaning, calcium oxide is added sequentially; during the third-stage scavenging, copper sulfate and zinc collector are added in the first stage scavenging, and zinc collector is added in the second and third stages scavenging; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded, and returned to the first-stage roughing in the lead flotation operation, and the middlings are regrinded to further improve the zinc recovery rate in the complex and disseminated high-sulfur-content lead-zinc sulfide ore.

[0007] The sulfur flotation operation includes: adding sulfuric acid and xanthate to the tailings slurry after the third stage of scavenging in the zinc flotation operation; then performing a roughing stage, a cleaning stage, and a scavenging stage; the tailings after the first cleaning stage and the concentrate after the first scavenging stage are returned to the roughing stage of the sulfur flotation operation.

[0008] The zinc removal operation of the sulfur concentrate includes: regrinding the sulfur concentrate after the first stage of sulfur flotation, adding lime (calcium oxide) during the regrinding process, adding copper sulfate and zinc collector to the regrinded slurry, and performing a first stage roughing, a first stage cleaning and a first stage scavenging. Calcium oxide is added during the first stage cleaning process, and zinc collector is added during the first stage scavenging process. The tailings after the first stage cleaning and the concentrate after the first stage scavenging are returned to the first stage roughing process of the zinc removal operation of the sulfur concentrate.

[0009] Preferably, the third stage of the lead flotation and zinc flotation operations is carried out using a flotation column; using a flotation column for scavenging improves the recovery of fine, over-ground particles.

[0010] Preferably, the zinc product obtained from the zinc dezincification operation of the sulfur concentrate is returned to the zinc roughing operation; the sulfur concentrate undergoes a zinc dezincification operation, and the dezincified product is returned to the zinc roughing operation, thereby improving the zinc mineral recovery rate.

[0011] Preferably, in the lead flotation operation, the ore particle size of the slurry after grinding of the raw ore is 65% to 75% with a particle size of -0.074 mm, the pH value of the roughing slurry is 8 to 9, and the pH value of the cleaning slurry is 9 to 10; the fineness of the middlings after regrinding is -0.038 mm with a particle size of 70% to 90%.

[0012] Preferably, in the zinc flotation operation, the roughing pulp has a pH value of 9-10, the cleaning pulp has a pH value of 10-11, and the middlings are regrinded to a fineness of -0.038 mm, accounting for 70-90%.

[0013] Preferably, the pH value of the roughing pulp in the sulfur flotation operation is 6.5 to 7.5, the pH value of the roughing pulp in the zinc removal operation of the sulfur concentrate is greater than 11, and the regrinding fineness is -0.038 mm accounting for 70 to 90%, thereby improving the sulfur recovery rate in complex and disseminated high sulfur content lead-zinc sulfide ores.

[0014] Preferably, in the lead flotation operation, the black reagent is one or more of butylammonium black reagent, No. 25 black reagent, and aniline black reagent; in the zinc flotation operation, the zinc collector is a combination reagent consisting of ethyl xanthate, ethyl thiocyanate, and butyl xanthate in a ratio of 5:4:1; the roughing pulp pH is 6.5-7.5, and the xanthate is one or more of butyl xanthate, pentylenetetrazine, and isoamyl xanthate;

[0015] Preferably, in the lead flotation operation, the tailings after the third stage of cleaning are returned to the second stage of cleaning, and the tailings after the second stage of cleaning are returned to the first stage of cleaning; the concentrate after the third stage of scavenging is returned to the second stage of scavenging, and the concentrate after the second stage of scavenging is returned to the first stage of scavenging.

[0016] Preferably, in the zinc flotation operation, the tailings after the third stage of cleaning are returned to the second stage of cleaning, and the tailings after the second stage of cleaning are returned to the first stage of cleaning; the concentrate after the third stage of scavenging is returned to the second stage of scavenging, and the concentrate after the second stage of scavenging is returned to the first stage of scavenging.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] (1) The recovery rate of useful minerals is improved by using a combination of column mill and flotation column to improve the recovery rate of fine and over-ground particles.

[0019] (2) The zinc dezincification operation is carried out on the sulfur concentrate and the dezincification product is returned to the zinc roughing operation, which avoids the loss of zinc minerals and pyrite and improves the recovery rate of zinc minerals.

[0020] (3) By combining column mill with middlings regrinding, the recovery rate of lead and zinc in complex and disseminated high sulfur content lead-zinc sulfide ores can be improved. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of a beneficiation method for complexly embedded high-sulfur-content lead-zinc sulfide ores according to the present invention. Detailed Implementation

[0022] The following will refer to the appendices in the embodiments of the present invention. Figure 1 The technical solutions in the embodiments of the present invention will be clearly and completely described as follows:

[0023] Example 1:

[0024] In the first embodiment of the present invention, a beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ore includes: lead flotation, zinc flotation, sulfur flotation, and dezincification of sulfur concentrate.

[0025] The lead flotation operation includes: adding calcium oxide, zinc sulfate, and a black reagent sequentially to the slurry after grinding the raw ore for lead sulfide flotation, wherein the ore particle size of the feed ore is -0.074mm, accounting for 65%; the black reagent is butyl ammonium black reagent; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging, wherein the third-stage scavenging is carried out using a flotation column, wherein the pH value of the roughing slurry is 8, and the pH value of the cleaning slurry is 9; calcium oxide is added sequentially during the third-stage cleaning, and black reagent is added sequentially during the third-stage scavenging; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded (regrinding fineness is -0.038mm, accounting for 70%) and returned to the raw ore slurry before the first-stage roughing.

[0026] The zinc flotation operation includes: adding copper sulfate, lime, and a zinc collector sequentially to the tailings slurry after the third stage scavenging in the lead flotation operation for zinc sulfide flotation; the zinc collector is a combination reagent consisting of ethyl xanthate, ethyl thiocyanate, and butyl xanthate in a ratio of 5:4:1; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging, wherein the third-stage scavenging is carried out using a flotation column, the pH value of the roughing slurry is 9, and the pH value of the cleaning slurry is 10. Calcium oxide is added sequentially during the three-stage cleaning process, and copper sulfate and a zinc collector are added during the first stage of the three-stage scavenging process, while a zinc collector is added during the second and third stages; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded, and returned to the first-stage roughing in the lead flotation operation, with a regrinding fineness of -0.038 mm accounting for 70%.

[0027] The sulfur flotation operation includes: adding sulfuric acid and xanthate to the tailings slurry after the third stage scavenging of the zinc flotation operation; the xanthate can be butyl xanthate; then performing a roughing stage, a cleaning stage, and a scavenging stage, with the roughing slurry pH value being 6.5; the tailings after the first cleaning stage and the concentrate after the first scavenging stage are returned to the first roughing stage of the sulfur flotation operation.

[0028] The zinc removal process for sulfur concentrate includes: regrinding the sulfur concentrate after the first stage of sulfur flotation, adding lime (calcium oxide) during regrinding, adding copper sulfate and zinc collector to the regrinded slurry, and performing a first stage roughing, a first stage cleaning, and a first stage scavenging. Calcium oxide is added during the first stage cleaning, and zinc collector is added during the first stage scavenging. The pH of the roughing slurry is greater than 12, and the regrinding fineness is -0.038 mm, accounting for 70%. The tailings from the first stage cleaning and the concentrate from the first stage scavenging are returned to the first stage roughing stage of the zinc removal process. The zinc product obtained from the zinc removal process is returned to the zinc roughing stage.

[0029] Using ore containing 1.52% lead, 3.81% zinc, and 17.95% sulfur, this process yields a lead concentrate grade of 61.12% with a lead recovery rate of 91.34%, a zinc concentrate grade of 49.56%, and a zinc recovery rate of 91.23%. Without using flotation columns to recover fine-grained minerals, the lead concentrate recovery rate decreases by 0.5%, and the zinc concentrate recovery rate decreases by 0.6%, even with similar product concentrate grades. If dezincification of the sulfur concentrate is not performed and the dezincified product is returned to the zinc flotation operation, the zinc concentrate recovery rate decreases by 1.3%.

[0030] Example 2:

[0031] In the first embodiment of the present invention, a beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ore includes: lead flotation, zinc flotation, sulfur flotation, and dezincification of sulfur concentrate.

[0032] The lead flotation operation includes: sequentially adding calcium oxide, zinc sulfate, and black dye to the slurry after grinding the raw ore for lead sulfide flotation, wherein the ore particle size of the feed ore is -0.074mm, accounting for 70%; the black dye is butyl ammonium black dye and No. 25 black dye; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging, wherein the third-stage scavenging is carried out using a flotation column, wherein the pH value of the roughing slurry is 9, and the pH value of the cleaning slurry is ~10; calcium oxide is added sequentially during the three-stage cleaning process, and black dye is added sequentially during the three-stage scavenging process; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded (regrinding fineness is -0.038mm, accounting for 80%) and returned to the raw ore slurry before the first-stage roughing.

[0033] The zinc flotation operation includes: adding copper sulfate, lime, and a zinc collector sequentially to the tailings slurry after the third stage scavenging in the lead flotation operation for zinc sulfide flotation; the zinc collector is a combination of ethyl xanthate, ethyl thiocyanate, and butyl xanthate in a ratio of 5:4:1; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging, wherein the third-stage scavenging is carried out using a flotation column, the pH value of the roughing slurry is 10, and the pH value of the cleaning slurry is 11. Calcium oxide is added sequentially during the three-stage cleaning process, and copper sulfate and a zinc collector are added during the first stage of the three-stage scavenging process, while a zinc collector is added during the second and third stages; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded, and returned to the first-stage roughing in the lead flotation operation, with a regrinding fineness of -0.038 mm accounting for 80%.

[0034] The sulfur flotation operation includes: adding sulfuric acid and xanthate to the tailings slurry after the third stage scavenging of the zinc flotation operation, wherein the xanthate is butyl xanthate and pentachlorophenate; then performing a roughing stage, a cleaning stage, and a scavenging stage, with the roughing slurry having a pH of 7; the tailings after the first cleaning stage and the concentrate after the first scavenging stage are returned to the first roughing stage of the sulfur flotation operation.

[0035] The zinc removal process for sulfur concentrate includes: regrinding the sulfur concentrate after the first stage of sulfur flotation, adding lime (calcium oxide) during regrinding; adding copper sulfate and zinc collector to the regrinded slurry; and performing a first stage roughing, a first stage cleaning, and a first stage scavenging. Calcium oxide is added during the first stage cleaning, and a zinc collector is added during the first stage scavenging. The pH of the roughing slurry is greater than 13, and the regrinding fineness is -0.038 mm, accounting for 80%. The tailings from the first stage cleaning and the concentrate from the first stage scavenging are returned to the first stage roughing stage of the zinc removal process. The zinc product obtained from the zinc removal process is returned to the zinc roughing stage.

[0036] Using ore containing 3.52% lead, 2.45% zinc, and 16.48% sulfur, this process yields a lead concentrate grade of 62.34% with a lead recovery rate of 92.45%, a zinc concentrate grade of 49.34%, and a zinc recovery rate of 90.11%. Without using flotation columns to recover fine-grained minerals, the lead concentrate recovery rate decreases by 0.7%, and the zinc concentrate recovery rate decreases by 0.4%, even with similar product concentrate grades. If dezincification of the sulfur concentrate is not performed and the dezincified product is returned to the zinc flotation operation, the zinc concentrate recovery rate decreases by 1.1%.

[0037] Example 3:

[0038] In the first embodiment of the present invention, a beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ore includes: lead flotation, zinc flotation, sulfur flotation, and dezincification of sulfur concentrate.

[0039] The lead flotation operation includes: adding calcium oxide, zinc sulfate, and a black dye sequentially to the slurry after grinding the raw ore for lead sulfide flotation, wherein the ore particle size of the feed ore is -0.074mm, accounting for 75%; the black dye is aniline black dye; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging, wherein the third-stage scavenging is carried out using a flotation column, wherein the pH value of the roughing slurry is 9, and the pH value of the cleaning slurry is 9; calcium oxide is added sequentially during the three-stage cleaning process, and black dye is added sequentially during the three-stage scavenging process; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded (regrinding fineness is -0.038mm, accounting for 90%) and returned to the raw ore slurry before the first-stage roughing.

[0040] The zinc flotation operation includes: adding copper sulfate, lime, and a zinc collector sequentially to the tailings slurry after the third stage scavenging in the lead flotation operation for zinc sulfide flotation; the zinc collector is a combination of ethyl xanthate, ethyl thiocyanate, and butyl xanthate in a ratio of 5:4:1; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging, wherein the third-stage scavenging is carried out using a flotation column, the pH value of the roughing slurry is 10, the pH value of the cleaning slurry is 10, calcium oxide is added sequentially during the three-stage cleaning process, copper sulfate and a zinc collector are added during the first stage scavenging, and a zinc collector is added during the second and third stages scavenging; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded, and returned to the first-stage roughing in the lead flotation operation, with a regrinding fineness of -0.038 mm accounting for 90%.

[0041] The sulfur flotation operation includes: adding sulfuric acid and xanthate (isoamyl xanthate) to the tailings slurry after the third stage of scavenging in the zinc flotation operation; then performing a roughing stage, a cleaning stage, and a scavenging stage, with the roughing slurry pH value being 7.5; and returning the tailings after the first cleaning stage and the concentrate after the first scavenging stage to the first roughing stage of the sulfur flotation operation.

[0042] The zinc removal process for sulfur concentrate includes: regrinding the sulfur concentrate after the first stage of sulfur flotation, adding lime (calcium oxide) during regrinding; adding copper sulfate and zinc collector to the regrinded slurry; and performing a first stage roughing, a first stage cleaning, and a first stage scavenging. Calcium oxide is added during the first stage cleaning, and a zinc collector is added during the first stage scavenging. The pH of the roughing slurry is 14, and the regrinding fineness is -0.038 mm (90%). The tailings from the first stage cleaning and the concentrate from the first stage scavenging are returned to the first stage roughing stage of the zinc removal process. The zinc product obtained from the zinc removal process is returned to the zinc roughing stage.

[0043] Using ore containing 0.89% lead, 1.67% zinc, and 15.23% sulfur, this process yields a lead concentrate grade of 59.78% with a lead recovery rate of 88.67%, a zinc concentrate grade of 47.67%, and a zinc recovery rate of 89.12%. Without using flotation columns to recover fine-grained minerals, the lead concentrate recovery rate decreases by 0.4%, and the zinc concentrate recovery rate decreases by 0.3%, even with similar product concentrate grades. If dezincification of the sulfur concentrate is not performed and the dezincified product is returned to the zinc flotation operation, the zinc concentrate recovery rate decreases by 1.7%.

[0044] In the three embodiments described above, in order to improve the lead recovery rate, specifically, in the lead flotation operation, the tailings after the third stage of cleaning are returned to the second stage of cleaning, and the tailings after the second stage of cleaning are returned to the first stage of cleaning; the concentrate after the third stage of scavenging is returned to the second stage of scavenging, and the concentrate after the second stage of scavenging is returned to the first stage of scavenging.

[0045] In the above three embodiments, in order to improve the zinc recovery rate, specifically, in the zinc flotation operation, the tailings after the third stage of cleaning are returned to the second stage of cleaning, and the tailings after the second stage of cleaning are returned to the first stage of cleaning; the concentrate after the third stage of scavenging is returned to the second stage of scavenging, and the concentrate after the second stage of scavenging is returned to the first stage of scavenging.

[0046] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concept, should be covered within the scope of protection of the present invention.

Claims

1. A beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ore, comprising: Lead flotation, zinc flotation, sulfur flotation, and zinc removal from sulfur concentrate; characterized by: The lead flotation operation includes: sequentially adding calcium oxide, zinc sulfate, and black reagent to the slurry after grinding the raw ore for lead sulfide flotation; the ore particle size fed into the slurry after grinding the raw ore is -0.074mm, accounting for 65% to 75%, and the pH value of the roughing slurry is 8 to 9, followed by a first-stage roughing, a third-stage cleaning, and a third-stage scavenging; calcium oxide is added sequentially during the third-stage cleaning, and black reagent is added sequentially during the third-stage scavenging; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded, and returned to the raw ore slurry before the first-stage roughing; the regrinding fineness of the middlings is -0.038mm, accounting for 70% to 90%; the third-stage scavenging of the lead flotation operation is carried out using a flotation column; The zinc flotation operation includes: adding copper sulfate, lime, and zinc collector sequentially to the tailings slurry after the third stage scavenging in the lead flotation operation for zinc sulfide flotation, with the roughing slurry pH value being 9-10; then performing a first-stage roughing, a third-stage cleaning, and a third-stage scavenging; during the third-stage cleaning, calcium oxide is added sequentially; during the third-stage scavenging, copper sulfate and zinc collector are added in the first stage scavenging, and zinc collector is added in the second and third stages scavenging; the tailings from the first cleaning and the concentrate from the first scavenging are mixed, regrinded, and returned to the first-stage roughing in the lead flotation operation, with the regrinding fineness of the middlings being -0.038mm accounting for 70-90%; the third-stage scavenging in the zinc flotation operation is carried out using a flotation column; The sulfur flotation operation includes: adding sulfuric acid and xanthate to the tailings slurry after the third stage scavenging of the zinc flotation operation; the pH value of the roughing slurry is 6.5-7.5; then performing a first stage roughing, a first stage cleaning, and a first stage scavenging; the tailings after the first stage cleaning and the concentrate after the first stage scavenging are returned to the first stage roughing of the sulfur flotation operation; The zinc removal operation of the sulfur concentrate includes: regrinding the sulfur concentrate after the first stage of sulfur flotation, adding lime during the regrinding process, and regrinding fineness to 70-90% of the particles being -0.038mm; adding copper sulfate and zinc collector to the regrinded slurry, and performing a first stage roughing, a first stage cleaning, and a first stage scavenging, adding calcium oxide during the first stage cleaning and adding zinc collector during the first stage scavenging, ensuring the pH value of the roughing slurry is greater than 11; returning the tailings after the first stage cleaning and the concentrate after the first stage scavenging to the first stage roughing stage of the zinc removal operation of the sulfur concentrate; and returning the zinc product obtained from the zinc removal operation of the sulfur concentrate to the zinc roughing operation.

2. The beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ore according to claim 1, characterized in that: In the lead flotation process described above, the pH value for the fine-grained process is 9-10.

3. The beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ores according to claim 1, characterized in that: In the zinc flotation process, the pH value for the refining process is 10-11.

4. The beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ore according to claim 2, characterized in that: In the lead flotation operation, the black reagent is one or more of butylammonium black reagent, No. 25 black reagent, and aniline black reagent; in the zinc flotation operation, the zinc collector is a combination reagent consisting of ethyl xanthate, ethyl thiocyanate, and butyl xanthate in a ratio of 5:4:1; in the sulfur flotation operation, the rougher xanthate is one or more of butyl xanthate, pentyle xanthate, and isoamyl xanthate.

5. The beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ores according to claim 1, characterized in that: In the aforementioned lead flotation operation, the tailings after the third stage of cleaning are returned to the second stage of cleaning, and the tailings after the second stage of cleaning are returned to the first stage of cleaning; The concentrate after the third stage of scavenging is returned to the second stage of scavenging, and the concentrate after the second stage of scavenging is returned to the first stage of scavenging.

6. The beneficiation method for complexly disseminated high-sulfur-content lead-zinc sulfide ores according to claim 1, characterized in that: In the zinc flotation operation, the tailings after the third stage of cleaning are returned to the second stage of cleaning, and the tailings after the second stage of cleaning are returned to the first stage of cleaning. The concentrate after the third stage of scavenging is returned to the second stage of scavenging, and the concentrate after the second stage of scavenging is returned to the first stage of scavenging.

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