A method for settling and backwater of low-grade complex and refractory lead-zinc ore

Abstract

The present application relates to a kind of low-grade complex refractory lead-zinc ore settlement and backwater method, belong to mineral processing water treatment technical field, the present application includes the following steps: adding flocculating agent and coagulant to oxidized lead-zinc ore tailing pulp, after solid-liquid separation, obtain clear liquid A;Flocculating agent is added to lead-zinc sulfide ore tailing pulp, after solid-liquid separation, obtain clear liquid B;Clear liquid A and clear liquid B are mixed according to the proportion of 5:3 after volume ratio, return as lead-zinc sulfide ore dressing process water;Or clear liquid A and clear liquid B are mixed according to the proportion of 3:2 after volume ratio, return as oxidized lead-zinc ore dressing process water.The present application can control the mixing ratio of oxidized ore backwater and lead-zinc sulfide ore backwater, respectively back to lead-zinc concentrate separation process and zinc concentrate flotation process, improve backwater utilization rate and do not affect mineral processing index.

Description

Technical Field

[0001] This invention relates to the field of mineral processing water treatment technology, and in particular to a sedimentation and water recycling method for low-grade, complex and difficult-to-process lead-zinc ore. Background Technology

[0002] In recent years, with the continuous exploitation of lead and zinc resources, easily beneficiated high-quality sulfide lead-zinc ore resources have become increasingly scarce, while complex and difficult-to-beneficiate oxide lead-zinc ore resources have gradually become the main targets of mineral processing. Low-grade, complex, and difficult-to-process lead-zinc ores have high slime content and fine particle size of valuable minerals, making their flotation processes and reagent regimes more complex. The types of flotation reagents used are also more numerous, resulting in more complex tailings wastewater composition, which seriously affects the effectiveness of wastewater reuse.

[0003] Existing technologies mostly target wastewater from sulfide ore beneficiation or beneficiation wastewater for specific mineral types. They lack targeted solutions for tailings sedimentation and wastewater treatment in low-grade, complex, and difficult-to-treat lead-zinc ores (especially mixed oxygen-sulfur ores). For example, Chinese patent CN116924534A discloses a method for lead-zinc ore tailings concentration, sedimentation, and wastewater reuse. The technical solution involves adding at least one of the following to the lead-zinc ore tailings: leachate from the mine stockpile, well water, or recycled tailings from sulfide lead-zinc ore beneficiation. The resulting slurry is concentrated and sedimented, and solid-liquid separation yields clarified liquid A. Clarified liquid A is then returned as process water for beneficiation of mixed oxygen-sulfur lead-zinc ores or oxidized lead-zinc ores. This method mixes leachate from the mine stockpile, well water, or recycled tailings from sulfide lead-zinc ore beneficiation into the oxidized ore beneficiation tailings, promoting concentration and sedimentation. However, it does not address the separate treatment and reuse of oxidized lead-zinc ore tailings slurry and sulfide lead-zinc ore tailings slurry.

[0004] Low-grade, complex, and difficult-to-process lead-zinc ore is first simultaneously floated to obtain sulfide lead-zinc concentrate. The tailings slurry is then activated and floated again to obtain single zinc oxide concentrate. The tailings from the zinc oxide concentrate are settled and filtered to produce oxide ore reclaimed water. The sulfide lead-zinc concentrate is then floated using a lead-first, then zinc flotation process to obtain lead sulfide concentrate and zinc sulfide concentrate. The tailings are settled to produce sulfide ore reclaimed water. Direct reuse of both oxide and sulfide ore reclaimed water negatively impacts beneficiation indicators. Organic components in the oxide lead-zinc ore reclaimed water, when returned to the sulfidation section, inhibit sulfide ore flotation, while residual xanthate and other collectors in the sulfide lead-zinc ore reclaimed water, entering the oxidation section, interfere with the selective separation of oxide minerals. This two-way cross-effect severely impacts beneficiation indicators. However, continuously using tap water in the flotation process will generate a large amount of wastewater, wasting water resources. Before flotation, oxidized lead-zinc ore often requires activation treatment with reagents such as sodium sulfide. The recycled water from sulfide lead-zinc ore contains effective residual sulfiding agents; using it in the oxidation stage can reduce the additional amount of sulfiding agents required. Furthermore, residual collectors and other organic matter in the recycled water can also be reused. Therefore, it is necessary to provide a sedimentation and recycled water method for low-grade, complex, and difficult-to-process lead-zinc ore, controlling the mixing ratio of oxidized ore recycled water and sulfide ore recycled water, and reusing them separately in the sulfide lead-zinc concentrate beneficiation process and the zinc oxide concentrate flotation process, thereby improving recycled water utilization without affecting beneficiation indicators. Summary of the Invention

[0005] To overcome the problems existing in the background technology, the present invention provides a settling and water recycling method for low-grade, complex and difficult-to-process lead-zinc ore. This method can control the mixing ratio of recycled water from oxidized ore and recycled water from sulfide ore, and reuse them respectively in the sulfide lead-zinc concentrate beneficiation process and the zinc oxide concentrate flotation process, thereby improving the water recycling rate without affecting the beneficiation indicators.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: This invention provides a method for settling and reclaiming water from low-grade, complex, and difficult-to-process lead-zinc ore, specifically including the following steps: (1) Add flocculant and coagulant to the tailings slurry of lead-zinc oxide ore. The amount of flocculant added is 4~5mg and coagulant added per liter of tailings slurry of lead-zinc oxide ore. After solid-liquid separation, clear liquid A is obtained. (2) Add flocculant to the tailings slurry of lead-zinc sulfide ore, the amount of flocculant added is 10~30mg per liter of tailings slurry of lead-zinc sulfide ore, after the reaction is complete, the solid and liquid are separated to obtain clear liquid B; (3) The clarified liquid A and the clarified liquid B are reused in the following ways: the clarified liquid A and the clarified liquid B are mixed in a volume ratio of 5:3 and returned as water for the beneficiation process of lead-zinc sulfide ore; or the clarified liquid A and the clarified liquid B are mixed in a volume ratio of 3:2 and returned as water for the beneficiation process of lead-zinc oxide ore.

[0007] In the above technical solution, the flocculant is polyacrylamide.

[0008] In the above technical solution, the coagulant is selected from at least one of polyaluminum chloride and polyferric sulfate.

[0009] In the above technical solution, the slurry concentration of the oxide lead-zinc ore tailings slurry and the sulfide lead-zinc ore tailings slurry is 20~25%.

[0010] In the above technical solution, the pH value of both clarified liquid A and clarified liquid B is 7.5~8, and the solid content is ≤300ppm.

[0011] In the above technical solution, the water used in the beneficiation process of lead-zinc sulfide ore in step (3) is the grinding water and flotation washing water used in the process of separating lead-zinc sulfide mixed concentrate into lead-zinc sulfide concentrate and zinc-sulfide concentrate.

[0012] In the above technical solution, the water used in the lead-zinc oxide ore beneficiation process in step (3) is the grinding water and flotation washing water for the lead-zinc oxide ore.

[0013] In the above technical solution, the sulfide lead-zinc ore tailings slurry mentioned in step (2) includes sulfide lead concentrate tailings slurry and sulfide zinc concentrate tailings slurry.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention addresses the issue of recycled water generated from low-grade, complex, and difficult-to-process lead-zinc ores. By controlling the mixing ratio of recycled water from oxidized lead-zinc ores and lead-zinc sulfide ores, and then recycling it to the lead-zinc sulfide concentrate beneficiation process and the zinc oxide concentrate flotation process according to different volume ratios, the utilization rate of recycled water is improved. Furthermore, the beneficiation indicators such as lead and zinc grades and lead and zinc recovery rates in the flotation-obtained lead sulfide concentrate, zinc sulfide concentrate, and zinc oxide concentrate are at the same level as those obtained from tap water flotation. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of this application will be described in further detail.

[0016] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0017] Example 1 A certain ore processing plant has a processing capacity of 1000 t / d for low-grade, complex, and difficult-to-process lead-zinc ore. The tailings slurry concentration of oxidized lead-zinc ore is 25%, and the tailings slurry concentration of lead sulfide and zinc sulfide concentrate is 23%.

[0018] (1) Polyacrylamide flocculant and polyaluminum chloride coagulant were added to the tailings slurry of lead-zinc ore. The amount added was 4.5 mg of flocculant and 25 mg of coagulant per liter of tailings slurry. The slurry was sent to a thickener for solid-liquid separation to obtain clarified liquid A. The pH value of clarified liquid A was measured to be 7.63 and the solid content was 200 ppm.

[0019] (2) Polyacrylamide flocculant was added to the tailings slurry of lead-zinc sulfide ore, wherein the tailings slurry of lead-zinc sulfide ore consisted of tailings slurry from lead sulfide concentrate and tailings slurry from zinc sulfide concentrate. The amount of flocculant added was 20 mg per liter of tailings slurry. The slurries were then sent to a thickener for solid-liquid separation. The resulting liquids were mixed to obtain clarified liquid B. The pH value of clarified liquid B was measured to be 7.78, and the solid content was 250 ppm.

[0020] (3) The resulting clarified liquid A and the resulting clarified liquid B are mixed at a volume ratio of 5:3 and returned to the process of separating lead sulfide concentrate and zinc sulfide concentrate as grinding water and flotation washing water. The beneficiation indicators are shown in Table 1 below.

[0021] Example 2 A certain ore processing plant has a processing capacity of 1000 t / d for low-grade, complex, and difficult-to-process lead-zinc ore. The tailings slurry concentration of oxidized lead-zinc ore is 20%, and the tailings slurry concentration of lead sulfide and zinc sulfide concentrate is 25%.

[0022] (1) Polyacrylamide flocculant and polyaluminum chloride coagulant were added to the tailings slurry of lead-zinc ore. The amount added was 4 mg of flocculant and 30 mg of coagulant per liter of tailings slurry. The slurry was sent to a thickener for solid-liquid separation to obtain clear liquid A. The pH value of clear liquid A was measured to be 7.5 and the solid content was 200 ppm.

[0023] (2) Polyacrylamide flocculant was added to the tailings slurry of lead-zinc sulfide ore, wherein the tailings slurry of lead-zinc sulfide ore consisted of tailings slurry from lead sulfide concentrate and tailings slurry from zinc sulfide concentrate. The amount of flocculant added was 30 mg per liter of tailings slurry. The slurries were then sent to a thickener for solid-liquid separation. The resulting liquids were mixed to obtain clarified liquid B. The pH value of clarified liquid B was measured to be 7.98, and the solid content was 300 ppm.

[0024] (3) The resulting clarified liquid A and the resulting clarified liquid B are mixed at a volume ratio of 5:3 and returned to the process of separating lead sulfide concentrate and zinc sulfide concentrate as grinding water and flotation washing water. The beneficiation indicators are shown in Table 2 below.

[0025] Example 3 A certain ore processing plant has a processing capacity of 1000 t / d for low-grade, complex, and difficult-to-process lead-zinc ore. The tailings slurry concentration of oxidized lead-zinc ore is 25%, and the tailings slurry concentration of lead sulfide and zinc sulfide concentrates is 25%.

[0026] (1) Polyacrylamide flocculant and polyaluminum chloride coagulant were added to the tailings slurry of lead-zinc oxide mine. The amount added was 5 mg of flocculant and 20 mg of coagulant per liter of tailings slurry. The slurry was sent to a thickener for solid-liquid separation to obtain clear liquid A. The pH value of clear liquid A was measured to be 7.80 and the solid content was 200 ppm.

[0027] (2) Polyacrylamide flocculant was added to the tailings slurry of lead-zinc sulfide ore, wherein the tailings slurry of lead-zinc sulfide ore consisted of tailings slurry from lead sulfide concentrate and tailings slurry from zinc sulfide concentrate. The amount of flocculant added was 10 mg per liter of tailings slurry. The slurries were then sent to a thickener for solid-liquid separation. The resulting liquids were mixed to obtain clarified liquid B. The pH value of clarified liquid B was measured to be 7.50, and the solid content was 200 ppm.

[0028] (3) Clarified liquid A and clarified liquid B are mixed in a volume ratio of 3:2 and returned to the oxide lead-zinc ore beneficiation process as grinding water and flotation washing water. The beneficiation indicators are shown in Table 3 below.

[0029] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that tap water was used directly as grinding water and flotation washing water in the process of separating lead sulfide concentrate and zinc sulfide concentrate from mixed lead-zinc oxide ore and lead-zinc sulfide concentrate.

[0030] The mineral processing indicators are shown in Table 4 below.

[0031] Comparative Example 2 Comparative Example 2 followed the same steps as Example 1 to obtain clarified liquid A, except that clarified liquid A was used as grinding water and flotation wash water in the process of separating lead sulfide concentrate and zinc sulfide concentrate from the mixed lead sulfide concentrate. The beneficiation parameters are shown in Table 5 below.

[0032] Comparative Example 3 The steps for obtaining clarified liquid A in Comparative Example 3 are the same as those in Example 1, except that clarified liquid A is used as grinding water and flotation washing water in the lead-zinc ore flotation process. The beneficiation parameters are shown in Table 6 below.

[0033] Comparative Example 4 Comparative Example 4 followed the same steps as Example 1 in obtaining clarified liquid B, except that clarified liquid B was directly used as grinding water and flotation wash water in the process of separating lead sulfide concentrate and zinc sulfide concentrate from the mixed lead sulfide concentrate. The beneficiation parameters are shown in Table 7 below.

[0034] Comparative Example 5 Comparative Example 5 followed the same steps as Example 1 to obtain clarified liquid B, except that clarified liquid B was directly used as grinding water and flotation wash water in the lead-zinc ore flotation process. The beneficiation parameters are shown in Table 8 below.

[0035] In summary, the beneficiation indices of Examples 1-3 and Comparative Examples 1-5 show that the lead and zinc grades and lead and zinc recovery rates of the lead sulfide concentrate, zinc sulfide concentrate, and zinc oxide concentrate obtained in Examples 1-3 are similar to those of Comparative Example 1, which directly uses tap water for flotation. This proves that the method of the present invention can achieve wastewater reuse, maximize the utilization rate of recycled water, and does not affect the beneficiation indices. However, in Comparative Examples 2 and 3, clarifying liquid A was directly used as grinding water and flotation wash water in the separation of lead sulfide concentrate and zinc sulfide concentrate and the beneficiation process of lead oxide zinc ore, respectively. In Comparative Examples 4 and 5, clarifying liquid B was directly used as grinding water and flotation wash water in the separation of lead sulfide concentrate and zinc sulfide concentrate and the beneficiation process of lead oxide zinc ore, respectively. This resulted in a slight decrease in the zinc grade of the zinc sulfide concentrate and the zinc oxide concentrate.

[0036] Finally, it should be noted that the above preferred embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail through the above preferred embodiments, those skilled in the art should understand that various changes can be made to it in form and detail without departing from the scope defined by the claims of the present invention.

Claims

1. A method for settling and reclaiming water from low-grade, complex, and difficult-to-process lead-zinc ore, characterized in that: Specifically, the following steps are included: (1) Add flocculant and coagulant to the tailings slurry of lead-zinc oxide ore. The amount of flocculant added is 4~5mg and coagulant added per liter of tailings slurry of lead-zinc oxide ore. After solid-liquid separation, clear liquid A is obtained. (2) Add flocculant to the tailings slurry of lead-zinc sulfide ore, the amount of flocculant added is 10~30mg per liter of tailings slurry of lead-zinc sulfide ore, and obtain clear liquid B after solid-liquid separation; (3) The clarified liquid A and the clarified liquid B are reused in the following ways: the clarified liquid A and the clarified liquid B are mixed in a volume ratio of 5:3 and returned as water for the beneficiation process of lead-zinc sulfide ore; or the clarified liquid A and the clarified liquid B are mixed in a volume ratio of 3:2 and returned as water for the beneficiation process of lead-zinc oxide ore.

2. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The flocculant mentioned is polyacrylamide.

3. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The coagulant is selected from at least one of polyaluminum chloride and polyferric sulfate.

4. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The slurry concentration of the oxide lead-zinc ore tailings slurry and the sulfide lead-zinc ore tailings slurry is 20-25%.

5. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The pH values ​​of both clarified solution A and clarified solution B are 7.5~8, and the solid content is ≤300ppm.

6. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The water used in the beneficiation process of lead-zinc sulfide ore in step (3) is the grinding water and flotation washing water used in the process of separating lead-zinc sulfide mixed concentrate into lead-zinc sulfide concentrate and zinc-zinc sulfide concentrate.

7. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The water used in the lead-zinc oxide ore beneficiation process in step (3) is grinding water and flotation washing water for lead-zinc oxide ore.

8. The settling and water recovery method for low-grade, complex, and difficult-to-process lead-zinc ore according to claim 1, characterized in that: The lead-zinc sulfide tailings slurry mentioned in step (2) includes lead sulfide concentrate tailings slurry and zinc sulfide concentrate tailings slurry.

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