Mineral processing technology for separating zinc concentrate

Abstract

The invention provides a beneficiation process for separating zinc concentrate, belongs to the technical field of mineral processing, and solves the problems of low roughing grade, high circulating load, large medicament consumption and high tailing grade of the existing zinc concentrate separation process. A lead mineral collecting agent, a zinc mineral inhibitor and a foaming agent are added into the ore pulp through lead mineral preferential flotation, one-time roughing and three-time concentration are carried out, lead concentrate is produced, and meanwhile zinc-containing tailings are obtained; first zinc concentrate with the grade of 53%-58% is produced through pre-separation; the pre-separated tailings are subjected to roughing, scavenging and concentration through a conventional flotation machine, and second zinc concentrate with the grade being 47%-50% is obtained; and finally, mixing the two concentrates according to the mass ratio to obtain the final zinc concentrate. According to the method, the follow-up circulation load is reduced by 40%-50%, the total reagent cost is reduced by 28%-32%, the tailing zinc grade is controlled to be 0.04%-0.11%, collaborative optimization of efficient zinc concentrate separation, cost reduction and tailing grade control is achieved, and the method is suitable for the high-grade zinc concentrate production scene.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, specifically relating to a beneficiation process for separating zinc concentrate, which is particularly suitable for beneficiation scenarios where the zinc concentrate grade is required and production costs and tailings grade need to be controlled. Background Technology

[0002] In zinc ore beneficiation, conventional zinc concentrate separation processes mainly rely on a three-stage process of "flotation roughing, flotation cleaning, and flotation scavenging". The core principle is to separate zinc minerals from gangue minerals through the interaction of flotation reagents and mineral particles, and finally obtain zinc concentrate products.

[0003] However, existing conventional processes have significant technical drawbacks: First, the roughing stage is limited by the separation efficiency of conventional flotation machines, and the highest grade of zinc concentrate produced by roughing can only reach about 40%, far from meeting the industrial demand for zinc concentrate grades of over 50%. Second, to compensate for the insufficient grade in roughing, multiple cleaning operations are required to improve the concentrate grade, which directly leads to a significant increase in the circulating load of subsequent cleaning stages (the circulating load is 30%-50% higher than ideal), and the concentration remains in the separation system for a longer period, resulting in… The problem of concentrate not being discharged in a timely manner seriously affects the efficiency of mineral processing production; thirdly, in order to ensure the zinc recovery rate in the scavenging process (to avoid the loss of zinc minerals with tailings), a large amount of flotation reagents need to be added to the system (the reagent consumption increases by 25%-40% compared to the theoretical minimum value), which significantly increases the cost of mineral processing production; fourthly, the combined effect of high circulating load and large amount of reagents leads to a significant increase in the risk of zinc content exceeding the standard in tailings. If the zinc grade of tailings exceeds 0.3%, it will cause resource waste and increase the environmental pressure and safety hazards of tailings storage.

[0004] In summary, existing conventional zinc concentrate beneficiation processes can no longer balance the production demands of "high grade, high efficiency, low cost, and low tailings grade," and an innovative process is urgently needed to address these technical challenges. Summary of the Invention

[0005] The purpose of this invention is to provide a beneficiation process for separating zinc concentrate, in order to solve the problems of low roughing grade, high circulating load, large reagent consumption and high tailings grade in existing zinc concentrate beneficiation processes, and to achieve synergistic optimization of efficient zinc concentrate beneficiation, cost reduction and tailings grade control.

[0006] The technical solution of the present invention is: 1. A beneficiation process for separating zinc concentrate, characterized by comprising the following steps: Step 1: Raw material pretreatment The lead-zinc ore is crushed and ground to a fineness of -200 mesh, accounting for 68%-78% of the total. A pH adjuster is added to adjust the slurry concentration to 25%-35% and the pH value of the slurry to 10.5-11.5. Step 2: Preferential flotation of lead minerals Lead mineral collector, zinc mineral inhibitor, and frother are added to the pretreated slurry after pH adjustment. The amount of lead mineral collector added is 80-100 g / t of ore, the amount of zinc mineral inhibitor added is 300-500 g / t of ore, and the amount of frother added is 5-15 g / t of ore. The slurry is then subjected to one roughing and three cleaning processes using a conventional flotation machine. The flotation time for the first roughing is 10±1 min, and the flotation time for the three cleaning processes is 5±1 min. A lead concentrate with a grade of ≥50% is produced, and zinc-containing tailings are obtained as raw material for subsequent zinc separation. Step 3: Pre-separation using jet microbubble flotation machine The zinc-containing tailings slurry obtained in step two is transported to a jet microbubble flotation machine. The jet microbubble flotation machine generates microbubbles with a diameter of 50-100μm. 300-550g / t of copper sulfate, 100-120g / t of xanthate, and 5-15g / t of No. 2 oil are added. After flotation for 7-9 minutes, a first zinc concentrate with a grade of 53%-58% is obtained. Step 4: Subsequent separation using conventional flotation machines The tailings from step three are transported to a conventional flotation system for roughing, scavenging, and cleaning in sequence. The roughing flotation time is 10 minutes, with the addition of 50-150 g / t copper sulfate, 20-100 g / t xanthate, and 5-20 g / t oil. The scavenging flotation time is 6 minutes, with the addition of 10-50 g / t copper sulfate, 10-60 g / t xanthate, and 5-15 g / t oil. The cleaning flotation time is 5 minutes, without the addition of reagents, to obtain a second zinc concentrate with a grade of 47%-50%. Step 5: Concentrate Mixing The first zinc concentrate from step three and the second zinc concentrate from step four are mixed at a mass ratio of 1:1.2 to 1:1.5 to obtain a final zinc concentrate with a grade of 50% to 52%, and the zinc grade of the tailings of the final zinc concentrate is controlled at 0.04% to 0.11%.

[0007] As a further improvement of the present invention, in step one, the pH adjuster is lime.

[0008] As a further improvement of the present invention, in step two, the lead mineral collector is ethyl thiocyanate; the zinc mineral inhibitor is zinc sulfate; and the foaming agent is No. 2 oil.

[0009] As a further improvement of the present invention, in step three, the flotation time is 7-9 minutes.

[0010] As a further improvement of the present invention, in step four, the roughing flotation time is 10 minutes, the scavenging flotation time is 6 minutes, and the cleaning flotation time is 5 minutes.

[0011] The beneficial effects of this invention are as follows: 1. Improved sorting efficiency: The jet microbubble flotation machine can directly produce high-grade first zinc concentrate through pre-sorting, without relying on multiple cleaning processes to improve the grade. The circulating load of the subsequent conventional flotation system is reduced by 40%-50%, the concentrate discharge cycle is shortened by 30%-40%, and the overall mineral processing production efficiency is increased by 25%-35%. 2. Reduced production costs: On the one hand, the amount of reagents used in the pre-separation stage of the jet microbubble flotation machine is small, and the reagents used in the subsequent conventional separation stages are reduced by 30%-35% compared with conventional processes due to the lower grade requirements, resulting in a 28%-32% reduction in total reagent costs; on the other hand, the reduced circulating load reduces equipment energy consumption (total equipment energy consumption is reduced by 15%-20%), further compressing production costs. 3. Controlling tailings grade: The jet microbubble flotation machine has high enrichment efficiency for zinc minerals. The subsequent scavenging process does not need to rely excessively on reagents to ensure recovery rate. The zinc grade in the tailings is stably controlled at 0.04%-0.11%, which is lower than 0.15%-0.3% of conventional processes, significantly reducing tailings resource waste and environmental safety risks. 4. Ensure product quality: Through the reasonable ratio of the first and second zinc concentrates, the final zinc concentrate grade is stabilized at over 50%, meeting the industrial production demand for high-grade zinc concentrate, and the grade fluctuation range is less than ±0.5%, significantly improving product quality stability. Attached Figure Description

[0012] Figure 1 This is a flow chart of the mineral processing technology for rapid separation of zinc concentrate according to the present invention. Detailed Implementation

[0013] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0014] like Figure 1 As shown, the jet microbubble flotation technology in Examples 1-3 can be implemented using the following existing equipment: Elite microbubble flotation machine, XMB series jet microbubble flotation machine, MCF series jet aerated flotation machine, CJW series jet microbubble flotation machine, JetFlo series jet flotation machine, and CircFlo series jet microbubble flotation machine.

[0015] Example 1

[0016] Step 1: Raw material pretreatment The lead-zinc ore is crushed and ground to a fineness of -200 mesh (68%). The slurry concentration is adjusted to 25%, and a pH adjuster (lime) is added to adjust the pH value of the slurry to 10.5. Step 2: Preferential flotation of lead minerals Add lead mineral collector, zinc mineral inhibitor and frother to the pretreated slurry after pH adjustment. The lead mineral collector is ethyl thiocyanate, and the addition amount is 80 g / t ore; the zinc mineral inhibitor is zinc sulfate, and the addition amount is 300 g / t ore; the frother is No. 2 oil, and the addition amount is 5 g / t ore. The process involves one roughing and three cleaning stages using a conventional flotation machine. The first roughing stage takes 9 minutes, and the three cleaning stages take 4 minutes. This produces lead concentrate with a grade of ≥50%, while also yielding zinc-containing tailings, i.e. lead flotation tailings, which are used as raw materials for subsequent zinc separation. Step 3: Pre-separation using jet microbubble flotation machine The zinc-containing tailings slurry obtained in step two is transported to a jet microbubble flotation machine. The flotation time is 7 minutes. The microbubble generated by the jet microbubble flotation machine has a diameter of 50 μm. 300 g / t copper sulfate, 100 g / t xanthate, and 5 g / t No. 2 oil are added. After flotation, a first zinc concentrate with a grade of 53% is obtained. Step 4: Subsequent separation using conventional flotation machines The tailings from step three are transported to a conventional flotation system for roughing, scavenging, and cleaning in sequence. For roughing, 50 g / t of copper sulfate, 20 g / t of xanthate, and 5 g / t of No. 2 oil are added. For scavenging, 10 g / t of copper sulfate, 10 g / t of xanthate, and 5 g / t of No. 2 oil are added. No reagents are added for cleaning, resulting in a second zinc concentrate with a grade of 47%. The roughing flotation time is 10 minutes, the scavenging flotation time is 6 minutes, and the cleaning flotation time is 5 minutes. Step 5: Concentrate Mixing The first zinc concentrate from step three and the second zinc concentrate from step four are mixed at a mass ratio of 1:1.2 to obtain a final zinc concentrate with a grade of 50%. The zinc grade of the tailings of the final zinc concentrate is controlled at 0.04%.

[0017] Example 2

[0018] Step 1: Raw material pretreatment The lead-zinc ore is crushed and ground to a fineness of -200 mesh (73%), the slurry concentration is adjusted to 30%, and a pH adjuster (lime) is added to adjust the pH value of the slurry to 11. Step 2: Preferential flotation of lead minerals Lead mineral collector, zinc mineral inhibitor, and foaming agent were added to the pretreated slurry after pH adjustment. The lead mineral collector was ethyl thiocyanate, with an addition amount of 90 g / t ore; the zinc mineral inhibitor was zinc sulfate, with an addition amount of 400 g / t ore; and the foaming agent was No. 2 oil, with an addition amount of 10 g / t ore. The process involves one roughing and three cleaning stages using a conventional flotation machine. The first roughing stage takes 10 minutes, and the three cleaning stages take 5 minutes. This produces lead concentrate with a grade of ≥50%, while also yielding zinc-containing tailings, i.e. lead flotation tailings, which are used as raw materials for subsequent zinc separation. Step 3: Pre-separation using jet microbubble flotation machine The zinc-containing tailings slurry obtained in step two is transported to a jet microbubble flotation machine. The flotation time is 8 minutes. The microbubble generated by the jet microbubble flotation machine has a diameter of 75 μm. 425 g / t of copper sulfate, 110 g / t of xanthate, and 10 g / t of No. 2 oil are added. After flotation, the first zinc concentrate with a grade of 56% is obtained. Step 4: Subsequent separation using conventional flotation machines The tailings from step three are transported to a conventional flotation system for roughing, scavenging, and cleaning in sequence. For roughing, 100 g / t of copper sulfate, 60 g / t of xanthate, and 10 g / t of No. 2 oil are added. For scavenging, 30 g / t of copper sulfate, 35 g / t of xanthate, and 10 g / t of No. 2 oil are added. No reagents are added for cleaning, resulting in a second zinc concentrate with a grade of 48%. The roughing flotation time is 10 minutes, the scavenging flotation time is 6 minutes, and the cleaning flotation time is 5 minutes. Step 5: Concentrate Mixing The first zinc concentrate from step three and the second zinc concentrate from step four are mixed at a mass ratio of 1:1.4 to obtain a final zinc concentrate with a grade of 51%. The zinc grade of the tailings of the final zinc concentrate is controlled at 0.07%.

[0019] Example 3

[0020] Step 1: Raw material pretreatment The lead-zinc ore is crushed and ground to a fineness of -200 mesh (78%). The slurry concentration is adjusted to 35%, and a pH adjuster (lime) is added to adjust the pH value of the slurry to 11.5. Step 2: Preferential flotation of lead minerals Add lead mineral collector, zinc mineral inhibitor and foaming agent to the pretreated slurry after pH adjustment. The lead mineral collector is ethyl thiocyanate, and the addition amount is 100g / t ore; the zinc mineral inhibitor is zinc sulfate, and the addition amount is 500g / t ore; the foaming agent is No. 2 oil, and the addition amount is 15g / t ore. The process involves one roughing and three cleaning stages using a conventional flotation machine. The first roughing stage takes 11 minutes, and the three cleaning stages take 6 minutes. This produces lead concentrate with a grade of ≥50%, while also yielding zinc-containing tailings, i.e. lead flotation tailings, which are used as raw materials for subsequent zinc separation. Step 3: Pre-separation using jet microbubble flotation machine The zinc-containing tailings slurry obtained in step two is transported to a jet microbubble flotation machine. The flotation time is 9 minutes. The microbubble generated by the jet microbubble flotation machine has a diameter of 100 μm. 550 g / t of copper sulfate, 120 g / t of xanthate and 15 g / t of No. 2 oil are added. After flotation, the first zinc concentrate with a grade of 58% is obtained. Step 4: Subsequent separation using conventional flotation machines The tailings from step three are transported to a conventional flotation system for roughing, scavenging, and cleaning in sequence. For roughing, 150 g / t of copper sulfate, 100 g / t of xanthate, and 20 g / t of No. 2 oil are added. For scavenging, 50 g / t of copper sulfate, 60 g / t of xanthate, and 15 g / t of No. 2 oil are added. No reagents are added for cleaning, resulting in a second zinc concentrate with a grade of 50%. The roughing flotation time is 10 minutes, the scavenging flotation time is 6 minutes, and the cleaning flotation time is 5 minutes. Step 5: Concentrate Mixing The first zinc concentrate from step three and the second zinc concentrate from step four are mixed at a mass ratio of 1:1.5 to obtain a final zinc concentrate with a grade of 52%. The zinc grade of the tailings of the final zinc concentrate is controlled at 0.11%.

[0021] Comparative Example 1 Comparative Example 1 did not incorporate jet microbubble flotation pre-separation technology. A lead-zinc sulfide ore from Gansu, after crushing and grinding, yielded a flotation feed with a particle size of -200 mesh accounting for 76.2% and a concentration of 32-35%. The traditional "lead first, then zinc" flotation process was used without jet microbubble pre-separation. The specific process is as follows: (1) Preferential flotation of lead minerals Lead coarse scavenging equipment: KYF70 flotation machine (conventional flotation equipment, suitable for coarse scavenging capacity requirements); Lead refining equipment: KYF8 flotation machine (matching the requirements of precision and miniaturization in lead refining); Additives: For coarse scavenging, add 90g / t of ethyl thiocyanate (collector) and 18g / t of No. 2 oil (frother). No additional additives are added during the fine scavenging stage. Flotation process: 1 roughing stage + 2 scavenging stages (KYF70 flotation machine) + 3 cleaning stages (KYF8 flotation machine).

[0022] (2) Conventional flotation of zinc minerals Zinc roughing equipment: Same as lead roughing equipment, using KYF70 flotation machine; Zinc refining equipment: KYF12 flotation machine (suitable for zinc refining throughput and separation precision); Reagent additions: For roughing, add 550g / t copper sulfate, 150g / t pentyl xanthate, and 25g / t ore of No. 2 oil; for scavenging, add 250g / t copper sulfate, 80g / t ore of pentyl xanthate, and 15g / t ore of No. 2 oil; for cleaning, add 90g / t copper sulfate and 50g / t ore of pentyl xanthate. Flotation process: 1 roughing stage + 1 scavenging stage (KYF70 flotation machine) + 3 cleaning stages (KYF12 flotation machine, three cleaning operations are completed according to production requirements).

[0023] Comparative Example 1 shows that: (1) Comparative Example 1: Zinc roughing (KYF70 flotation machine) was limited by the efficiency of conventional flotation. The grade of the roughing zinc concentrate was only 38.6%. Even after three cleaning processes (KYF12 flotation machine), the final grade of the zinc concentrate was only 49.5%, which did not reach the target grade of more than 50%. (2) In Comparative Example 1, the zinc flotation cycle load is as high as 65%, and the KYF12 flotation machine needs to be frequently started and stopped to clean the residual slurry, which leads to the delay in concentrate discharge and shortens the average daily effective production time by 1.5 hours; (3) In order to ensure the zinc recovery rate, the total reagent consumption of Comparative Example 1 reached 890g / t copper sulfate and 330g / t pentyl xanthate, resulting in high costs; (4) The zinc tailings grade of Comparative Example 1 was 0.17%. Some zinc minerals were lost with the tailings, and the KYF70 flotation machine needed to be stopped regularly for cleaning due to coarse particles, which further caused metal loss.

[0024] As can be seen from Examples 1-3: (1) The process of the present invention directly produces a first zinc concentrate with a grade of 55.3% by jet microbubble pre-separation. The KYF70 flotation machine (zinc rough scavenging) only needs to process the low-grade tailings, and the grade of the rough zinc concentrate is increased to 42.6%. After two more cleaning processes (KYF12 flotation machine), the grade of the second zinc concentrate reaches 48.7%. After mixing, the final grade of the zinc concentrate is 50.8%, which meets the target of more than 50%. (2) The zinc flotation cycle load of the present invention is reduced to 45%, the KYF12 flotation machine does not need to be cleaned frequently, the average daily effective production time is extended by 1.2 hours, and the production efficiency is increased by 40%; (3) The total reagent consumption of the process of the present invention is reduced to 400g / t copper sulfate and 115g / t pentyl xanthate, which are 55.0% and 58.9% lower than those of the comparative example, respectively, significantly reducing costs; (4) The zinc tailings grade of the present invention is reduced to 0.078% (meeting the standard). Due to the jet microbubble pre-separation to remove coarse particles, the KYF70 flotation machine reduces the frequency of shutdown cleaning by 70% and the metal loss by 1.3 percentage points.

[0025] The process flow of this invention is simple, and the jet microbubble flotation machine can be directly connected in series with existing conventional flotation machine systems, making the equipment configuration simple and reliable. It can also significantly solve the problems of low roughing grade, high circulating load, high reagent consumption, and high tailings grade in existing zinc concentrate separation processes, while achieving efficient resource recovery and utilization, and has broad application prospects.

Claims

1. A beneficiation process for separating zinc concentrate, characterized in that, Includes the following steps: Step 1: Raw material pretreatment The lead-zinc ore is crushed and ground to a fineness of -200 mesh, accounting for 68%-78% of the total. A pH adjuster is added to adjust the slurry concentration to 25%-35% and the pH value of the slurry to 10.5-11.

5. Step 2: Preferential flotation of lead minerals Lead mineral collector, zinc mineral inhibitor, and frother are added to the pretreated slurry after pH adjustment. The amount of lead mineral collector added is 80-100 g / t of ore, the amount of zinc mineral inhibitor added is 300-500 g / t of ore, and the amount of frother added is 5-15 g / t of ore. The slurry is then subjected to one roughing and three cleaning processes using a conventional flotation machine. The flotation time for the first roughing is 10±1 min, and the flotation time for the three cleaning processes is 5±1 min. A lead concentrate with a grade of ≥50% is produced, and zinc-containing tailings are obtained as raw material for subsequent zinc separation. Step 3: Pre-separation using jet microbubble flotation machine The zinc-containing tailings slurry obtained in step two is transported to a jet microbubble flotation machine. The jet microbubble flotation machine generates microbubbles with a diameter of 50-100μm. 300-550g / t of copper sulfate, 100-120g / t of xanthate, and 5-15g / t of No. 2 oil are added. After flotation for 7-9 minutes, a first zinc concentrate with a grade of 53%-58% is obtained. Step 4: Subsequent separation using conventional flotation machines The tailings from step three are transported to a conventional flotation system for roughing, scavenging, and cleaning in sequence. The roughing flotation time is 10 minutes, with the addition of 50-150 g / t copper sulfate, 20-100 g / t xanthate, and 5-20 g / t oil. The scavenging flotation time is 6 minutes, with the addition of 10-50 g / t copper sulfate, 10-60 g / t xanthate, and 5-15 g / t oil. The cleaning flotation time is 5 minutes, without the addition of reagents, to obtain a second zinc concentrate with a grade of 47%-50%. Step 5: Concentrate Mixing The first zinc concentrate from step three and the second zinc concentrate from step four are mixed at a mass ratio of 1:1.2 to 1:1.5 to obtain a final zinc concentrate with a grade of 50% to 52%, and the zinc grade of the tailings of the final zinc concentrate is controlled at 0.04% to 0.11%.

2. The beneficiation process for separating zinc concentrate according to claim 1, characterized in that: In step one, the pH adjuster is lime.

3. The beneficiation process for separating zinc concentrate according to claim 1, characterized in that: In step two, the lead mineral collector is ethyl thiocyanate; the zinc mineral inhibitor is zinc sulfate; and the foaming agent is No. 2 oil.

4. The beneficiation process for separating zinc concentrate according to claim 1, characterized in that: In step three, the flotation time is 7-9 minutes.

5. The beneficiation process for separating zinc concentrate according to claim 1, characterized in that: In step four, the roughing flotation time is 10 minutes, the scavenging flotation time is 6 minutes, and the cleaning flotation time is 5 minutes.

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