A method of flotation separation for reducing zinc from zinc-containing sulphide concentrates

Abstract

The application belongs to the technical field of mineral processing, and specifically discloses a flotation separation method for reducing zinc content from zinc-containing sulfur concentrate, which can effectively cope with the fluctuation of zinc content in the raw ore through the combination strategy of grading regulation and control and gradient zinc depression and zinc removal, can stably control the zinc content in the sulfur concentrate to be below 0.5%, solves the risk of product sluggishness, provides multiple technical paths, can be flexibly selected according to the properties of different mine ores and the on-site equipment conditions, has good universality, dynamically adjusts the amount of the depressant according to the zinc content in the raw ore, and avoids the cost increase caused by excessive addition, and through industrial verification, the cost of the newly added zinc removal reagent is about 10-12 yuan / ton of concentrate, and the economic benefits are remarkable.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically discloses a flotation separation method for reducing zinc in zinc-containing sulfur concentrate. Background Technology

[0002] In the beneficiation of sulfide ores such as molybdenum and copper mines, sulfur (FeS2, pyrite) is recovered as an associated component. However, with the increase in mining depth and changes in ore properties, the problem of excessive zinc content in sulfur concentrate products has become increasingly prominent. Taking Luoyang Molybdenum's China region as an example, zinc in the Sandaozhuang mining area mainly exists in the form of sphalerite (ZnS) in lithologies such as wollastonite-garnet hornfels, felsic hornfels, and skarn. The zinc grade in different lithologies generally ranges from 0.004% to 0.068%, showing significant differences. In addition, the different ore blending ratios of each beneficiation unit lead to drastic fluctuations in the zinc content of sulfur concentrate, seriously affecting the sales price of sulfur concentrate and even causing the risk of unsold products.

[0003] In existing sulfur flotation processes, copper sulfate is commonly used as an activator for pyrite. However, copper ions also activate sphalerite, reducing the difference in floatability between pyrite and sphalerite and increasing the difficulty of inhibition. Industrially, a combination of zinc sulfate and sodium metabisulfite as inhibitors has been attempted for zinc inhibition, but the inhibition effect is poor when the zinc content of the raw ore is high. Even adjusting the reagent consumption to 40 g / t still fails to meet the target, and reagent costs rise sharply. Some companies use reverse flotation for zinc removal from sulfur concentrate, but the zinc removal yield is low, the adaptability is poor, and the zinc removal effect is unsatisfactory. The zinc content in the sulfur concentrate remains between 0.7% and 2.0%, far exceeding the critical control value of 0.5%.

[0004] Therefore, there is an urgent need to develop a zinc removal method for sulfur concentrate that can adapt to fluctuations in the zinc content of the raw ore, has high dezincification efficiency, and is economically viable. Summary of the Invention

[0005] To address the problems in the background art, this invention discloses a flotation separation method for reducing zinc content in zinc-containing sulfur concentrate. The method involves graded control of the zinc content in the raw ore and employs a combined strategy of graded zinc suppression and enhanced zinc removal to effectively control the zinc content in the sulfur concentrate.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A flotation separation method for reducing zinc in zinc-containing sulfur concentrate involves detecting the zinc grade of the raw ore and selecting the appropriate processing path based on the zinc grade of the raw ore. (1) The zinc grade of the raw ore is ≤0.015%. The conventional sulfur flotation process is adopted. Zinc sulfate and sodium metabisulfite combined inhibitors are added to the cleaning section after sulfur roughing to suppress zinc, so that the zinc content of the flotation sulfur concentrate is less than 0.5%; (2) The zinc grade of the raw ore is 0.015% to 0.03%. The conventional sulfur flotation process is adopted. The sulfur concentrate obtained by flotation is slurry adjusted to control the slurry concentration to 25% to 35%. pH adjuster, residual reagent eliminator, activator and collector are added to the slurry in sequence. The slurry after adjustment is fed into the zinc removal flotation equipment for one or two reverse flotation zinc removal operations. The zinc removal foam is zinc-containing tailings. The product in the tank is the zinc-reduced sulfur concentrate. The zinc content of the zinc-reduced sulfur concentrate is less than 0.5%. (3) The zinc grade of the raw ore is greater than 0.03%. The conventional sulfur flotation process is adopted. Zinc sulfate and sodium metabisulfite combined inhibitors are added to the cleaning section after sulfur roughing to suppress zinc. The sulfur concentrate obtained by flotation is slurry adjusted to control the slurry concentration to 25% to 35%. pH adjuster, residual reagent eliminator, activator and collector are added to the slurry in sequence. The slurry after adjustment is fed into the zinc removal flotation equipment for one or two reverse flotation zinc removal operations. The zinc removal foam is zinc-containing tailings. The product in the tank is zinc-reduced sulfur concentrate. The zinc content of the zinc-reduced sulfur concentrate is less than 0.5%.

[0007] Furthermore, in the flotation separation method for reducing zinc from zinc-containing sulfur concentrate, the mass ratio of zinc sulfate to sodium metabisulfite in the combined inhibitor is 1:1, and the amount of combined inhibitor added in processing path (1) and processing path (3) is 5-10 g / t and 10-40 g / t respectively based on the raw ore.

[0008] Furthermore, in the flotation separation method for reducing zinc from zinc-containing sulfur concentrate, the amounts of pH adjuster, residual reagent eliminator, activator, and collector added, calculated based on the raw ore or flotation sulfur concentrate, are 4–8 kg / t, 500–1000 g / t, 200–400 g / t, and 100–200 g / t, respectively.

[0009] Furthermore, in the flotation separation method for reducing zinc from zinc-containing sulfur concentrate, the pH adjuster is lime, the residual reagent eliminator is hydrogen peroxide, the activator is copper sulfate, and the collector is xanthate or ethyl thiocyanate.

[0010] Furthermore, in the flotation separation method for removing zinc from zinc-containing sulfur concentrate, the flotation time for reverse flotation dezincification is 8–15 min, and the aeration rate is 0.5–1.2 m³ / (m²·min).

[0011] Furthermore, in the flotation separation method for removing zinc from zinc-containing sulfur concentrate, the zinc removal flotation equipment is a flotation column or a flotation machine.

[0012] Compared with the prior art, the beneficial effects of the present invention are: 1. Excellent zinc reduction effect: By combining graded regulation of zinc content in raw ore with a step-by-step zinc suppression and dezincification strategy, the fluctuation of zinc content in raw ore can be effectively addressed, and the zinc content of sulfur concentrate can be stably controlled below 0.5%, thus solving the risk of unsold products. 2. Controllable reagent costs: The dosage of inhibitors is dynamically adjusted according to the zinc content of the raw ore to avoid cost increases caused by excessive addition. Industrial verification shows that the cost of the newly added zinc removal reagent is about 10-12 yuan / ton of concentrate, resulting in significant economic benefits. 3. High adaptability: It provides multiple technical approaches, which can be flexibly selected according to the properties of different mine ores and on-site equipment conditions, and has good universality; 4. Good adaptability to recycled water: To address the interference of residual xanthate and copper ions in the recycled water on the flotation process, hydrogen peroxide is added to eliminate residual reagents, ensuring the stability of the zinc removal operation in complex recycled water systems. Detailed Implementation

[0013] To better understand the present invention, the following embodiments further illustrate the content of the invention, but the scope of protection of the present invention is not limited to the following embodiments. Numerous specific details are set forth in the following description to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the present invention can be practiced without one or more of these details.

[0014] The conventional sulfur flotation process in this invention is existing technology. It refers to using flotation processes such as one roughing-two scavenging-one cleaning-one cleaning scavenging, two roughing-one cleaning, or two roughing-two cleaning-one cleaning scavenging to process molybdenum tailings to obtain flotation sulfur concentrate. The specific sulfur flotation process selected depends on the ore grade. The process involves one roughing, two scavenging, one cleaning, and one cleaning scavenging: First, the molybdenum tailings are roughed to obtain rough concentrate and rough tailings. The rough concentrate is then cleaned once to obtain sulfur concentrate and clean tailings. The rough tailings are then scavenged a second time to obtain scavenged concentrate and scavenged tailings. The clean tailings are then cleaned once to obtain clean scavenged concentrate and concentrate tailings. The scavenged concentrate and clean scavenged concentrate are combined and returned to the roughing process. The concentrate tailings and scavenged tailings are then directly discarded. Two roughing and one cleaning process: First, the molybdenum tailings are roughed to obtain rough concentrate I and rough tailings I. Rough concentrate I is then roughed to obtain rough concentrate II and rough tailings II. Rough concentrate II is then cleaned to obtain sulfur concentrate and cleaned tailings. Rough tailings I, rough tailings II and cleaned tailings become the discarded tailings. The process involves two roughing processes, two cleaning processes, and one scavenging process: First, the molybdenum tailings undergo a roughing process to obtain rough concentrate I and rough tailings I. Rough concentrate I undergoes a second roughing process to obtain rough concentrate II and rough tailings II. Rough concentrate II undergoes a first cleaning process to obtain sulfur concentrate I and cleaned tailings I. Sulfur concentrate I undergoes a second cleaning process to obtain sulfur concentrate II and cleaned tailings II. Cleaned tailings I undergo a scavenging process to obtain scavenged concentrate and scavenged tailings. The scavenged concentrate is returned to the first cleaning process. Rough tailings I, rough tailings II, cleaned tailings II, and scavenged tailings become the discarded tailings.

[0015] Example 1: Using the sulfur flotation system of Luoyang Molybdenum Group Co., Ltd. (Luoyang Molybdenum) as an example, ore with a zinc content of 0.020% to 0.026% was processed. The sulfur flotation adopted a "one roughing, two scavenging, one cleaning, and one cleaning scavenging" flotation process. The sulfur concentrate obtained from the flotation was slurry-adjusted to control the slurry concentration to 25% to 35%. Lime 6 kg / t was added to the slurry to adjust the pH value to 9 to 11, hydrogen peroxide 800 g / t was added to remove residual xanthate, copper sulfate 300 g / t was added to activate sphalerite, and xanthate 150 g / t or ethyl thiocyanate 120 g / t was added. The slurry-adjusted was fed into the zinc removal flotation equipment for two reverse flotation zinc removal operations. Zinc removal was performed using a φ2.5×10m flotation column for 10 minutes. The sulfur concentrate had a sulfur grade of 44.44% and a zinc content of 0.399%. Zinc was removed using a flotation machine with a flotation time of 10 minutes. The sulfur concentrate had a sulfur grade of 43.75% and a zinc content of 0.467%. The dezinc removal effect of the flotation column is better than that of the flotation machine, and the additional reagent cost is 10.69-11.42 yuan / ton of concentrate.

[0016] Example 2: Using a three-strong unit sulfur flotation system as an example, this method was applied to process ores with low zinc content (0.008%–0.012%). The sulfur flotation process employed a "one roughing, two scavenging, one cleaning, and one cleaning scavenging" flow. A combined inhibitor of zinc sulfate and sodium metabisulfite was added to the cleaning stage. The dosage of the combined inhibitor was 7 g / t based on the raw ore, and the mass ratio of zinc sulfate to sodium metabisulfite was 1:1. The resulting sulfur concentrate had a stable zinc content below 0.25%, demonstrating a significant zinc inhibition effect. The total reagent cost was approximately RMB 0.82 per ton of raw ore, resulting in good economic benefits.

[0017] Example 3: Using the sulfur flotation system of Luoyang Molybdenum Group's China Region II beneficiation unit as an example, ore with a zinc content of 0.030%–0.040% was processed. The sulfur flotation adopted a "one roughing, two scavenging, one cleaning, one cleaning scavenging" flotation process. In the cleaning stage, a combined inhibitor of zinc sulfate and sodium metabisulfite was added. The amount of the combined inhibitor added was 40 g / t based on the raw ore, and the mass ratio of zinc sulfate to sodium metabisulfite was 1:1. The obtained flotation sulfur concentrate had a zinc content >0.5%. The flotation sulfur concentrate was then slurry-adjusted to control the slurry concentration. The pH of the slurry was adjusted to 9-11 by adding 8 kg / t of lime, 1000 g / t of hydrogen peroxide to remove residual xanthate, 400 g / t of copper sulfate to activate sphalerite, and 200 g / t of ethyl thiocyanate. The adjusted slurry was then fed into a dezincification flotation device for two reverse flotation dezincification operations. A φ2.5×10m flotation column was used for dezincification, with a flotation time of 10 min and a dezincification yield of 18%-25%. After dezincification, the zinc content of the sulfur concentrate was reduced to below 0.5%.

[0018] Example 4: Using the sulfur flotation system of Luoyang Molybdenum Group's China Region II beneficiation unit as an example, ore with a zinc content of 0.010% to 0.014% was processed. The sulfur flotation adopted a "one roughing, two scavenging, one cleaning, and one cleaning scavenging" flotation process. A combination of zinc sulfate and sodium metabisulfite was added to the cleaning stage. The amount of the combination inhibitor added was 5 g / t based on the raw ore, and the mass ratio of zinc sulfate to sodium metabisulfite was 1:1. The obtained flotation sulfur concentrate had a zinc content of less than 0.25%, with a significant zinc inhibition effect. The total reagent cost was about 0.82 yuan / ton of raw ore, resulting in good economic benefits.

[0019] Example 5: The raw ore had a sulfur grade of 0.63% and a zinc content of 0.022%. The sulfur flotation adopted a "two roughing, two cleaning, one cleaning scavenging" flotation process. The sulfur concentrate obtained from the flotation was slurry-adjusted to control the slurry concentration at 25%. Lime (5 kg / t) was added to the slurry to adjust the pH value to 9-11, hydrogen peroxide (600 g / t) was added to remove residual xanthate, copper sulfate (200 g / t) was added to activate sphalerite, and xanthate (180 g / t) was added. The slurry-adjusted was fed into a zinc removal flotation device for two reverse flotation zinc removal operations. Zinc removal was carried out using a flotation machine with a flotation time of 10 minutes. The sulfur concentrate had a sulfur grade of 44.92%, a zinc content of 0.483%, and a sulfur recovery rate of 40.46%.

[0020] Example 6: The raw ore had a sulfur grade of 0.60% and a zinc content of 0.026%. Sulfur flotation employed a "two-roughing-one-cleaning" process. The sulfur concentrate obtained from flotation was slurry-adjusted to a concentration of 35%. Lime (6 kg / t) was added sequentially to adjust the pH to 9-11, hydrogen peroxide (700 g / t) was added to remove residual xanthate, copper sulfate (300 g / t) was added to activate sphalerite, and ethyl thiocyanate (150 g / t) was added. The slurry was then fed into a dezincification flotation unit for two reverse flotation operations. A φ2.5×10m flotation column was used for dezincification, with a flotation time of 10 minutes. The sulfur concentrate had a sulfur grade of 47.61%, a zinc content of 0.415%, and a sulfur recovery rate of 43.45%.

[0021] Comparative Example 1: The raw ore had a sulfur grade of 0.80% and a zinc content of 0.026%. The sulfur flotation adopted a "two roughing and one cleaning" flotation process, and the sulfur concentrate obtained by flotation had an S grade of 43.74%, a Zn content of 1.790%, and a sulfur recovery rate of 35.00%.

[0022] Comparative Example 2: The raw ore had a sulfur grade of 0.64% and a zinc content of 0.020%. The sulfur flotation adopted a "two roughing, two cleaning, and one scavenging" flotation process. The flotation yielded a sulfur concentrate with a sulfur grade of 44.46%, a zinc content of 0.968%, and a sulfur recovery rate of 36.25%.

[0023] The experimental results of Examples 1-6 demonstrate that the present invention, through a combination of graded regulation of zinc content in raw ore and stepwise zinc suppression and dezincification strategy, can effectively address fluctuations in zinc content in raw ore and stably control the zinc content of sulfur concentrate to below 0.5%.

[0024] A comparison of Examples 5 and 6 with Comparative Examples 1 and 2 shows that reverse flotation dezincification can stably control the zinc content of sulfur concentrate below 0.5% and improve the sulfur recovery rate.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.

Claims

1. A flotation separation method for reducing zinc in zinc-containing sulfur concentrate, characterized in that, The zinc grade of the incoming raw ore is tested, and the appropriate processing path is selected based on the zinc grade of the raw ore: (1) The zinc grade of the raw ore is ≤0.015%. The conventional sulfur flotation process is adopted. Zinc sulfate and sodium metabisulfite combined inhibitors are added to the cleaning section after sulfur roughing to suppress zinc, so that the zinc content of the flotation sulfur concentrate is less than 0.5%; (2) The zinc grade of the raw ore is 0.015% to 0.03%. The conventional sulfur flotation process is adopted. The sulfur concentrate obtained by flotation is slurry adjusted to control the slurry concentration to 25% to 35%. pH adjuster, residual reagent eliminator, activator and collector are added to the slurry in sequence. The slurry after adjustment is fed into the zinc removal flotation equipment for one or two reverse flotation zinc removal operations. The zinc removal foam is zinc-containing tailings. The product in the tank is the zinc-reduced sulfur concentrate. The zinc content of the zinc-reduced sulfur concentrate is less than 0.5%. (3) The zinc grade of the raw ore is greater than 0.03%. The conventional sulfur flotation process is adopted. Zinc sulfate and sodium metabisulfite combined inhibitors are added to the cleaning section after sulfur roughing to suppress zinc. The sulfur concentrate obtained by flotation is slurry adjusted to control the slurry concentration to 25% to 35%. pH adjuster, residual reagent eliminator, activator and collector are added to the slurry in sequence. The slurry after adjustment is fed into the zinc removal flotation equipment for one or two reverse flotation zinc removal operations. The zinc removal foam is zinc-containing tailings. The product in the tank is zinc-reduced sulfur concentrate. The zinc content of the zinc-reduced sulfur concentrate is less than 0.5%.

2. The flotation separation method for reducing zinc in zinc-bearing sulfur concentrate according to claim 1, characterized in that, The mass ratio of zinc sulfate to sodium metabisulfite in the combined inhibitor is 1:

1. The amount of combined inhibitor added in treatment path (1) and treatment path (3) is 5-10 g / t and 10-40 g / t respectively, based on the raw ore.

3. The flotation separation method for reducing zinc in zinc-bearing sulfur concentrate according to claim 2, characterized in that, The addition amounts of pH adjuster, residual reagent eliminater, activator, and collector, calculated based on the raw ore or flotation sulfur concentrate used for slurry preparation, are 4–8 kg / t, 500–1000 g / t, 200–400 g / t, and 100–200 g / t, respectively.

4. The flotation separation method for reducing zinc in zinc-bearing sulfur concentrate according to claim 3, characterized in that, The pH adjuster is lime, the residual reagent remover is hydrogen peroxide, the activator is copper sulfate, and the collector is xanthate or ethionyl ether.

5. The flotation separation method for reducing zinc in zinc-containing sulfur concentrate according to claim 3, characterized in that, reverse... The flotation time for zinc removal is 8–15 min, and the aeration rate is 0.5–1.2 m³ / (m²·min).

6. The flotation separation method for reducing zinc in zinc-bearing sulfur concentrate according to claim 3, characterized in that, Zinc removal flotation equipment consists of flotation columns or flotation machines.