A beneficiation method for improving zinc recovery in carbon-containing fine-grained lead-zinc ore

Abstract

This invention discloses a beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore, belonging to the field of mineral processing technology. This method improves upon the conventional "pre-decarbonization-lead-zinc preferential flotation" process. On one hand, it employs a carbon-suppressing zinc flotation method for secondary zinc recovery from the carbon concentrate. On the other hand, it changes the conventional process of returning middlings from the primary zinc concentrate to the rougher. Instead, the middlings obtained after the primary concentrate are incorporated into the final concentrate for further refining. The tailings from the primary concentrate are concentrated and then discarded. The rough concentrate obtained from the carbon-suppressing zinc flotation and the rough concentrate obtained from the secondary concentrate discarded from the primary zinc concentrate are combined and then refined using a flotation column. Compared to the conventional "pre-decarbonization-lead-zinc preferential flotation" process, this method offers advantages such as higher zinc recovery, more stable flotation parameters, and higher economic benefits. Furthermore, it is highly adaptable to the same type of ore and has significant potential for widespread application.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and in particular to a beneficiation method for improving the zinc recovery rate of carbonaceous fine-grained lead-zinc ore. Background Technology

[0002] In the flotation of carbonaceous lead-zinc ores, the presence of a large amount of carbon makes the pulp system complex. On the one hand, carbonaceous minerals cover the surface of the lead-zinc ore, hindering the contact between reagents and the target minerals, and they also non-selectively adsorb a large amount of flotation reagents, leading to a surge in reagent consumption and a decrease in the floatability of lead and zinc. On the other hand, carbonaceous minerals easily enter the concentrate product, resulting in a low concentrate grade that is difficult to meet the requirements for qualified products. To address the adverse effects of carbonaceous minerals, it is usually necessary to pre-decarbonize before flotation of lead and zinc, or to add carbon mineral depressants during lead-zinc flotation.

[0003] A certain carbon-containing lead-zinc ore has a high zinc grade (greater than 10%) and fine lead-zinc intercalation. When using the method of suppressing preferential flotation of carbon, lead, and zinc, there is a phenomenon of simultaneous suppression or simultaneous flotation of carbon and lead. In order to avoid the loss of lead minerals, it is necessary to adopt the principle of pre-decarbonization and then separately float lead and zinc. However, for some zinc minerals with good natural floatability, the zinc loss rate of the carbon concentrate product obtained by pre-decarbonization is large. On the other hand, because the mineral yield and slime content in zinc beneficiation are high, the middlings are directly returned to the zinc roughing process in closed-circuit production, which deteriorates the zinc roughing process, resulting in a large loss of zinc metal. Summary of the Invention

[0004] The purpose of this invention is to provide a beneficiation method for improving the zinc recovery rate of carbon-containing fine-grained lead-zinc ore, thereby solving the problems existing in the prior art.

[0005] To achieve the above objectives, this invention provides a beneficiation method for improving the zinc recovery rate of carbonaceous fine-grained lead-zinc ore, comprising the following steps: Step 1: Performing carbon-suppressing flotation on the zinc-containing carbon concentrate obtained from pre-decarburization to obtain a first zinc rough concentrate and a carbon concentrate; Step 2: Instead of returning the middlings from the first-stage zinc beneficiation operation to the zinc roughing operation, performing zinc scavenging to obtain zinc scavenging middlings and zinc scavenging tailings, and combining the zinc scavenging middlings with the first-stage beneficiation concentrate for subsequent zinc beneficiation operations; Step 3: Performing zinc re-selection on the zinc scavenging tailings obtained in Step 2 to obtain a second zinc rough concentrate and zinc re-selection tailings; Step 4: Combining the first zinc rough concentrate obtained in Step 1 and the second zinc rough concentrate obtained in Step 3 and performing flotation column beneficiation to obtain a zinc concentrate.

[0006] Preferably, the carbon-suppressing and zinc-floating roughing in step 1 includes: adjusting the zinc-containing carbon concentrate to a mass concentration of 30% to 35%, and sequentially adding pH adjuster lime, carbon inhibitor sodium humate, zinc mineral activator copper sulfate, collector butyl xanthate and frother No. 2 oil for roughing.

[0007] Preferably, the zinc grade of the middlings obtained from the zinc refining operation I in step 2 is 5% to 7%, and the zinc grade of the zinc concentrate tailings is 2% to 4%.

[0008] Preferably, the zinc re-selection in step 3 includes: concentrating the zinc concentrate tailings to a mass concentration of 25% to 30%, then adding pH adjuster lime, collector butyl xanthate and frother No. 2 oil for roughing to obtain a second zinc rough concentrate and zinc re-selection tailings.

[0009] Preferably, the flotation column refining in step 4 includes: adjusting the combined first and second zinc rough concentrates to a mass concentration of 20% to 25%, adding lime as a pH adjuster, and refining using a flotation column.

[0010] Preferably, the amounts of the pH adjuster lime, carbon inhibitor sodium humate, zinc mineral activator copper sulfate, collector butyl xanthate, and frother No. 2 oil are determined by experiment based on the differences in ore properties.

[0011] Preferably, the amounts of the pH adjuster lime, the collector butyl xanthate, and the frother No. 2 oil are determined by experiment based on the differences in ore properties.

[0012] Preferably, the lead grade of the carbonaceous fine-grained lead-zinc ore is 0.5% to 2.0%, the zinc grade is 10% to 15%, the lead mineral is mainly galena, the zinc mineral is mainly sphalerite and ferrosphalerite, and the carbonaceous matter is mainly free carbon and organic carbon.

[0013] Preferably, the concentrate obtained from the flotation column in step 4 is combined into zinc concentrate, and the middlings are combined into tailings.

[0014] Preferably, the zinc re-selection tailings obtained in step 3 are combined and entered into the tailings.

[0015] Compared with the prior art, the present invention has the following advantages and technical effects: This invention provides a beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore. By improving the conventional "pre-decarbonization-lead-zinc preferential flotation" process, it employs a carbon-suppressing zinc flotation method to achieve secondary zinc recovery from the carbon concentrate, reducing zinc loss in the carbon concentrate. Furthermore, it changes the conventional process of returning middlings from the primary zinc cleaning process to the roughing stage. Instead, the middlings obtained after fine scavenging are incorporated into the primary cleaning concentrate for subsequent cleaning, avoiding direct return of middlings and deteriorating the zinc roughing process, thus improving the stability of the roughing operation. Simultaneously, the tailings from the fine scavenging are concentrated and then discarded. The rough concentrate obtained from carbon-suppressing zinc flotation and the rough concentrate obtained from the secondary cleaning of the primary zinc middlings are combined and then cleaned using a flotation column, fully utilizing the advantages of flotation columns for fine-grained mineral recovery and high enrichment ratios. Compared to the conventional "pre-decarbonization-lead-zinc preferential flotation" process, this method offers advantages such as higher zinc recovery, more stable flotation indicators, and higher economic benefits. It also has strong adaptability to similar ores and has significant potential for widespread application. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention.

[0017] Figure 1 This is a process flow diagram of an embodiment of a mineral processing method for improving zinc recovery in carbon-containing fine-particle lead-zinc ore according to the present invention.

[0018] Figure 2 This is a flow chart of a conventional "pre-decarbonization-lead-zinc preferential flotation" process. Detailed Implementation

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other. The described embodiments are merely some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art without inventive effort are within the scope of protection of this invention. The invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] like Figure 1As shown, this invention provides a beneficiation method for improving the zinc recovery rate of carbon-containing fine-grained lead-zinc ore, comprising the following steps: Step 1: Performing carbon-suppressing flotation on the zinc-containing carbon concentrate obtained from pre-decarbonization to obtain a first zinc rough concentrate and a carbon concentrate; Step 2: Instead of returning the middlings from the first-stage zinc beneficiation operation to the zinc roughing operation, performing zinc scavenging to obtain zinc scavenging middlings and zinc scavenging tailings, and combining the zinc scavenging middlings with the first-stage beneficiation concentrate for subsequent zinc beneficiation operations; Step 3: Performing zinc re-selection on the zinc scavenging tailings obtained in Step 2 to obtain a second zinc rough concentrate and zinc re-selection tailings; Step 4: Combining the first zinc rough concentrate obtained in Step 1 and the second zinc rough concentrate obtained in Step 3 and performing flotation column beneficiation to obtain a zinc concentrate.

[0021] Step 1 involves using carbon-suppressing flotation to rough the zinc-bearing carbon concentrate obtained from pre-decarbonization. This effectively recovers the zinc metal lost in the carbon concentrate, yielding a first zinc rough concentrate, significantly reducing the zinc loss rate in the carbon concentrate. Step 2 involves using a zinc fine sweep instead of returning the middlings from the first zinc cleaning operation to the zinc roughing operation. This avoids the deteriorating impact of directly returning the middlings to the zinc roughing operation, making the flotation indicators of the roughing operation more stable. At the same time, the fine sweep operation initially recovers zinc from the middlings. Step 3 involves zinc re-selection of the zinc fine sweep tailings, further recovering the zinc metal from the tailings to obtain a second zinc rough concentrate, minimizing zinc metal loss. Step 4 combines the first and second zinc rough concentrates and performs column flotation. Utilizing the high enrichment ratio and suitability of the flotation column for fine-grained mineral recovery, a high-grade zinc concentrate can be obtained in a single cleaning operation, simplifying the process and improving the zinc recovery rate.

[0022] Further optimization of the scheme: Step 1, the roughing of carbon-suppressed zinc flotation includes: adjusting the zinc-containing carbon concentrate to a mass concentration of 30% to 35%, and sequentially adding pH adjuster lime, carbon inhibitor sodium humate, zinc mineral activator copper sulfate, collector butyl xanthate and frother No. 2 oil for roughing.

[0023] By adjusting the zinc-containing carbon concentrate to a suitable mass concentration of 30%–35%, the pulp is guaranteed to have good fluidity and reagent dispersibility. By sequentially adding the pH adjuster lime, the carbon inhibitor sodium humate, the zinc mineral activator copper sulfate, the collector butyl xanthate, and the frother No. 2 oil, the flotation of carbonaceous matter can be effectively suppressed, while activating and collecting zinc minerals, achieving efficient separation of zinc and carbon, and obtaining a high-zinc grade first zinc rough concentrate.

[0024] Further optimization of the scheme resulted in a zinc grade of 5%–7% in the middlings of the zinc concentrate obtained from the zinc concentrate I operation in step 2, and a zinc grade of 2%–4% in the zinc concentrate tailings.

[0025] By performing zinc fine sweeping on the middlings of the primary beneficiation process with a zinc grade of 5% to 7%, the direct return of this middlings to the roughing operation is avoided. At the same time, the fine sweeping operation yields zinc fine sweeping tailings with a zinc grade of 2% to 4%, creating conditions for subsequent beneficiation and ensuring full recovery of zinc metal.

[0026] Further optimization of the scheme: In step 3, zinc re-selection includes: concentrating the zinc concentrate tailings to a mass concentration of 25% to 30%, then adding pH adjuster lime, collector butyl xanthate and frother No. 2 oil for roughing to obtain a second zinc rough concentrate and zinc re-selection tailings.

[0027] By concentrating the zinc concentrate tailings to a mass concentration of 25%–30%, the pulp concentration in the re-selection operation was increased, enhancing the flotation effect. By adding lime (pH adjuster), butyl xanthate (collector), and No. 2 oil (frother) for roughing, the residual zinc minerals in the tailings can be effectively recovered to obtain a second zinc rough concentrate, further improving the overall zinc recovery rate.

[0028] Further optimization of the scheme: Step 4 of the flotation column refining includes: adjusting the combined first and second zinc rough concentrates to a mass concentration of 20% to 25%, adding lime as a pH adjuster, and then refining using a flotation column.

[0029] By adjusting the combined first and second zinc rough concentrates to a mass concentration of 20%–25%, the uniformity and stability of the pulp within the flotation column are ensured. The addition of lime, a pH adjuster, provides a suitable alkaline environment for the flotation of zinc minerals. The use of a flotation column for fine-grained mineral cleaning leverages its advantages of high recovery efficiency and high enrichment ratio for fine-grained minerals, allowing for the acquisition of high-quality zinc concentrate in a single cleaning operation, thus simplifying the process and reducing costs.

[0030] To further optimize the scheme, the dosages of pH adjuster lime, carbon inhibitor sodium humate, zinc mineral activator copper sulfate, collector butyl xanthate, and frother No. 2 oil were determined by experiment based on the differences in ore properties.

[0031] By determining the dosage of each reagent through experiments based on the differences in ore properties, the matching between the reagent system and the ore properties was ensured, so that the flotation process could achieve the best results and the adaptability to carbonaceous fine-grained lead-zinc ores of different sources and properties was guaranteed.

[0032] To further optimize the scheme, the dosage of pH adjuster lime, collector butyl xanthate, and frother No. 2 oil was determined by experiment based on the differences in ore properties.

[0033] By determining the dosage of reagents in zinc re-selection based on the differences in ore properties through experiments, the high efficiency of the re-selection process was ensured, and the effective recovery of residual zinc metal from zinc concentrate tailings was guaranteed.

[0034] Further optimization of the scheme resulted in a lead grade of 0.5%–2.0% and a zinc grade of 10%–15% for carbonaceous fine-grained lead-zinc ore. The lead minerals were mainly galena, and the zinc minerals were mainly sphalerite and ferrosphalerite. The carbonaceous matter consisted mainly of free carbon and organic carbon.

[0035] By limiting the applicable ore properties of this method, the scope of application of this invention is clarified. For carbonaceous fine-grained lead-zinc ore with the above characteristics, this method can significantly improve the zinc recovery rate and solve the problem of large zinc loss in conventional processes.

[0036] In a further optimized scheme, the concentrate obtained from the flotation column in step 4 is combined into the zinc concentrate, and the middlings are combined into the tailings.

[0037] By merging the concentrate obtained from the flotation column into the final zinc concentrate, the quality of the concentrate product is ensured; by merging the middlings into the tailings, the circulation and accumulation of middlings in the process is avoided, the process flow is simplified, and the stable operation of the entire flotation system is guaranteed.

[0038] To further optimize the scheme, the zinc re-selection tailings obtained in step 3 are merged into the tailings.

[0039] By merging zinc reprocessing tailings into the final tailings, centralized treatment of tailings is achieved, simplifying the process and reducing production costs.

[0040] This invention provides a beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore. First, the zinc-bearing carbon concentrate obtained from a conventional "pre-decarbonization-lead-zinc preferential flotation" process undergoes carbon-suppressing flotation for roughing. By adding carbon inhibitors such as sodium humate, carbonaceous matter is effectively suppressed, activating and recovering zinc minerals to obtain a first zinc rough concentrate, significantly reducing zinc loss in the carbon concentrate. Simultaneously, the conventional process of returning middlings from the primary zinc cleaning process to the roughing process is changed. The middlings from the primary cleaning process (5%–7% zinc grade) are subjected to a zinc fine sweep, avoiding direct return of middlings and interference with the roughing operation, thus stabilizing the flotation parameters of the roughing operation. The middlings obtained from the zinc fine sweep are combined with the primary cleaning concentrate for subsequent cleaning, while the zinc fine sweep tailings are re-selected. The zinc fine sweep tailings are then concentrated and re-selected to obtain a second zinc rough concentrate, further recovering zinc metal from the tailings. Finally, the first zinc rough concentrate recovered from the carbon concentrate and the second zinc rough concentrate recovered from the middlings re-concentration are combined and finely cleaned using a flotation column. Utilizing the high enrichment ratio and suitability of the flotation column for fine-grained mineral recovery, a high-grade zinc concentrate can be obtained in a single fine-grained process. The middlings from this fine-grained process are then incorporated into the tailings. The entire process flow is rationally designed and tightly integrated, maximizing the recovery of zinc metal from fine-grained carbonaceous lead-zinc ore. This solves the technical challenges of high zinc loss from the carbon concentrate, deterioration of roughing by middlings return, and difficulty in recovering fine-grained zinc minerals in conventional processes, achieving a significant improvement in zinc recovery rate.

[0041] Example 1 The test ore sample was from a foreign carbon-bearing lead-zinc mine, with a lead grade of 1.70%, a zinc grade of 11.50%, and a carbon grade of 3.68%. The zinc minerals showed uneven particle size distribution, ranging from 0.020 mm to 0.147 mm. Conventional beneficiation processes were employed (see attached...). Figure 2 ) and the process described in this invention (attached) Figure 1 The comparison of the obtained test indicators is shown in Table 1 below: Table 1 Comparison of test results in Example 1 As shown in Table 1, when the above ore is processed using the method described in this invention, the flotation index obtained is 3.48 percentage points higher than that obtained by conventional processes, with the zinc grade of zinc concentrate not decreasing significantly.

[0042] Example 2 The test ore sample was a carbon-bearing lead-zinc mine in Inner Mongolia, with a lead grade of 0.90%, a zinc grade of 10.21%, and a carbon grade of 5.59%. The lead minerals had a relatively coarse particle size, and the zinc minerals had an uneven particle size distribution, with zinc minerals of 0.020 mm accounting for approximately 20%. The test indicators obtained using conventional beneficiation processes and the process described in this invention are compared in Table 2 below (due to the coarse particle size of the lead minerals and the low lead grade of the original ore, the lead flotation did not involve regrinding, unlike the process flow diagram in the specification). Table 2 Comparison of test results in Example 2 As shown in Table 2, when the above ore is processed using the method described in this invention, the flotation index obtained is 3.82 percentage points higher than that obtained by conventional processes, with the zinc grade of zinc concentrate not decreasing significantly.

[0043] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A beneficiation method for improving zinc recovery in carbon-containing fine-grained lead-zinc ore, characterized in that, Includes the following steps: Step 1: The zinc-bearing carbon concentrate obtained from pre-decarburization is subjected to carbon suppression and zinc flotation roughing to obtain the first zinc rough concentrate and carbon concentrate; Step 2: The middlings from the first zinc refining operation are not returned to the zinc roughing process, but are instead subjected to zinc finishing to obtain zinc finishing middlings and zinc finishing tailings. The zinc finishing middlings are then combined with the first zinc refining concentrate for subsequent zinc refining operations. Step 3: Perform zinc re-selection on the zinc concentrate tailings obtained in Step 2 to obtain a second zinc rough concentrate and zinc re-selection tailings; Step 4: Combine the first zinc rough concentrate obtained in Step 1 and the second zinc rough concentrate obtained in Step 3, and then perform flotation column cleaning to obtain zinc concentrate.

2. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 1, characterized in that, The carbon-suppressing zinc flotation roughing process described in step 1 includes: adjusting the zinc-containing carbon concentrate to a mass concentration of 30% to 35%, and sequentially adding pH adjuster lime, carbon inhibitor sodium humate, zinc mineral activator copper sulfate, collector butyl xanthate and frother No. 2 oil for roughing.

3. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 1, characterized in that, The zinc grade of the middlings obtained from the zinc beneficiation process I in step 2 is 5% to 7%, and the zinc grade of the zinc concentrate tailings is 2% to 4%.

4. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 1, characterized in that, The zinc re-selection in step 3 includes: concentrating the zinc concentrate tailings to a mass concentration of 25% to 30%, then adding pH adjuster lime, collector butyl xanthate and frother No. 2 oil for roughing to obtain a second zinc rough concentrate and zinc re-selection tailings.

5. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 1, characterized in that, The flotation column refining process described in step 4 includes: adjusting the combined first and second zinc rough concentrates to a mass concentration of 20%–25%, adding lime as a pH adjuster, and then refining using a flotation column.

6. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 2, characterized in that, The amounts of the pH adjuster lime, carbon inhibitor sodium humate, zinc mineral activator copper sulfate, collector butyl xanthate, and frother No. 2 oil were determined by experiment based on the differences in ore properties.

7. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 4, characterized in that, The amounts of the pH adjuster lime, the collector butyl xanthate, and the frother No. 2 oil were determined by experiment based on the differences in ore properties.

8. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 1, characterized in that, The carbonaceous fine-grained lead-zinc ore has a lead grade of 0.5%–2.0% and a zinc grade of 10%–15%. The lead mineral is mainly galena, and the zinc mineral is mainly sphalerite and ferrosphalerite. The carbonaceous matter is mainly free carbon and organic carbon.

9. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 1, characterized in that, The concentrate obtained from the flotation column in step 4 is combined into zinc concentrate, and the middlings are combined into tailings.

10. The beneficiation method for improving zinc recovery in carbonaceous fine-grained lead-zinc ore according to claim 3, characterized in that, The zinc re-selection tailings obtained in step 3 are combined and entered into the tailings.

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