Beneficiation method of low-grade refractory lead-zinc oxide ore

Abstract

The application belongs to the technical field of mineral processing, and particularly discloses a beneficiation method for low-grade and refractory oxidized lead-zinc ore, which comprises the following steps: crushing and screening the oxidized lead-zinc ore to obtain material with a particle size of 10-40 mm, removing waste rocks by photoelectric separation, and obtaining ore raw materials with improved grade; finely crushing the ore raw materials, and then screening and photoelectric separating the materials; screening the-10 mm powder ore materials, and separating the coarse particle materials by a cyclone; screening the overflow to remove waste rocks, screening the sand to obtain materials meeting the particle size requirements, adding chemicals to the materials, mixing and floating the materials, removing the chemicals, and obtaining mixed concentrates after the chemicals are removed; adding sodium sulfite and zinc sulfate to separate lead and zinc, and respectively obtaining lead concentrates and zinc concentrates. The application significantly reduces the consumption of chemicals, reduces the interference of slimes, and improves the lead-zinc recovery rate by two-stage pre-throwing waste and oxygen-sulfur mixed flotation system, and is suitable for efficient comprehensive utilization of low-grade oxidized lead-zinc ore.

Description

Technical Field

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

[0002] Lead-zinc oxide ores are generally classified as oxide ores when the proportion of lead-zinc oxide ore exceeds 30%, mixed ores when it is 10%-30%, and sulfide ores when it is below 10%. Therefore, lead-zinc oxide ores often contain both oxide and sulfide components. The grade of lead-zinc oxide ores is determined by the lead and zinc content in the ore; if the lead and zinc content is less than 10%, it is defined as a low-grade lead-zinc oxide ore.

[0003] my country is rich in oxide lead-zinc ore resources. For example, the Lanping oxide lead-zinc ore deposit in Yunnan Province has a content exceeding 14 million tons, and the Huoshaoyun oxide lead-zinc ore deposit in Xinjiang Uygur Autonomous Region is expected to have a content exceeding 21 million tons. However, these ores are typically characterized by low grade, fine-grained mineral distribution, complex occurrence forms, and a wide variety of associated gangue minerals. Beneficiation using existing technologies results in low recovery rates and is extremely difficult.

[0004] The existing methods for processing oxidized lead-zinc ore, as known to us, mainly include the following steps:

[0005] 1. Pretreatment is carried out through desliming;

[0006] 2. After desliming, the material undergoes three-stage crushing and two-stage screening. Following screening, it is either subjected to photoelectric separation for waste disposal or to heavy media separation for waste disposal. The photoelectric separation waste disposal process is described below. Figure 2 The process is long and complex, and the waste rate is relatively low.

[0007] 3. Flotation: The main flotation methods include sulfide flotation, fatty acid flotation, and chelating agent flotation. Sulfide flotation is sensitive to slime and usually requires pre-desliming, but the desliming process leads to a significant loss of metals, especially for low-grade ores with fine and dispersed particle sizes. Although chelating agent flotation has good selectivity for some oxidized minerals, the large amount of chelating agents required and their high cost result in high processing costs for low-grade ores, making it less common in practical applications. Fatty acid reagents have very active carboxyl functional groups and can float almost all minerals, but their poor selectivity makes it difficult to obtain high-grade concentrates.

[0008] The existing technology involves flotation of lead first, then zinc, and sulfur first, then oxygen, which produces four products: lead sulfide concentrate, zinc sulfide concentrate, lead oxide concentrate, and zinc oxide concentrate. This process requires segmented flotation, is complex, and uses a single reagent system.

[0009] For the flotation of lead sulfide, the depressant is ZnSO4, and the collector is xanthate.

[0010] Zinc sulfide flotation, activator: CuSO4;

[0011] Lead oxide flotation: sodium sulfide + xanthate;

[0012] Zinc oxide flotation: sodium sulfide + amine.

[0013] Generally, zinc oxide ore is mainly composed of zinc. Zinc oxide needs to be activated by sulfidation, but excessive sulfidation agent will inhibit sphalerite, thus resulting in low recovery rate.

[0014] It can be seen that existing mineral processing methods generally suffer from many problems, such as complex mineral processing procedures, high reagent consumption, difficulty in wastewater treatment and reuse, low recovery rate (generally about 60%-70%), and high production costs. As a result, a large amount of low-grade and difficult-to-process oxide lead-zinc ore resources have not been effectively developed and utilized.

[0015] With the continued growth in demand for lead and zinc metals and the gradual depletion of available sulfide lead-zinc ore resources, oxide lead-zinc ores are playing an increasingly prominent role in the supply of lead and zinc resources. Therefore, how to effectively develop and utilize low-grade and difficult-to-process oxide lead-zinc ores is a pressing problem that needs to be solved. Summary of the Invention

[0016] To address the aforementioned problems in existing technologies, this invention provides a beneficiation method for low-grade and difficult-to-process oxidized lead-zinc ore. The aim is to effectively shorten the process flow of existing technologies, reduce investment, decrease reagents, avoid mud-forming and crushing, and improve recovery rate, thereby enhancing the comprehensive utilization level of oxidized lead-zinc ore resources.

[0017] The beneficiation method for low-grade and difficult-to-process oxidized lead-zinc ore provided by this invention includes the following steps: 1) Crushing and screening the raw oxidized lead-zinc ore to obtain materials with a particle size of 10-40mm, using photoelectric separation to remove waste rock and obtain ore raw materials with improved grade; the ore raw materials are then finely crushed and screened and photoelectric separated, with +40mm material undergoing medium crushing and -10mm fine ore material entering the fine ore bin;

[0018] 2) The powdered ore in the powder ore bin is screened, with the oversize material being separated by a hydrocyclone and the undersize material entering the grinding and classification process; the separation product of the hydrocyclone is screened, and the overflow is screened by upper and lower double-layer screens, with the oversize material of the upper screen being removed as waste rock; the undersize sand is screened by upper and lower double-layer screens, with the oversize material of the upper screen entering the grinding and classification process.

[0019] 3) After the material from step 2) enters the grinding and classification process, the material that meets the particle size requirements is obtained;

[0020] 4) The material obtained in step 3) that meets the particle size requirements is subjected to lead-zinc-oxygen-sulfur mixed flotation. Lime, sodium sulfide, copper sulfate, sodium hexametaphosphate, water glass, xanthate, black powder, ethyl thiocyanate, amine, phosphate ester, and foaming agent are added to the lead-zinc-oxygen-sulfur mixed flotation equipment.

[0021] 5) After lead, zinc, oxygen and sulfur are mixed and floated, mixed flotation and cleaning and mixed flotation and scavenging are configured. The mixed flotation and cleaning and scavenging are returned in sequence. The mixed concentrate after mixed flotation and cleaning is subjected to mixed flotation and de-reagent treatment to obtain the de-reagented mixed concentrate.

[0022] 6) Sodium sulfite and zinc sulfate are added to the mixed concentrate obtained in step 5) to perform lead-zinc separation treatment, and lead concentrate and zinc concentrate are obtained respectively.

[0023] According to some specific embodiments of the present invention, in step 1), the +40 material is subjected to medium crushing, sieved and then enters photoelectric sorting.

[0024] According to some specific embodiments of the present invention, step 1) uses an upper and lower double-layer sieve to obtain materials with a particle size of 10-40 mm; step 2) the lower double-layer sieve has a screen hole size 0.1-0.3 mm smaller than the upper double-layer sieve.

[0025] According to some specific embodiments of the present invention, in step 2), the powdered ore in the powder ore bin and the hydrocyclone product are screened, and the screening particle size is controlled at 0.3-0.5 mm.

[0026] According to some specific embodiments of the present invention, in step 3), materials larger than the target particle size are ground during classification and then returned to classification.

[0027] According to some specific embodiments of the present invention, in step 3), the separation product of the hydrocyclone is screened:

[0028] The overflow from the hydrocyclone is screened using upper and lower double-layer screens. The material oversize of the upper screen is removed as waste rock, while the material oversize of the lower screen is concentrated, removed by magnetic separation, and then recycled as heavy medium. The material undersize of the lower screen is directly returned for reuse as heavy medium.

[0029] The sludge from the hydrocyclone is screened using upper and lower double-layer screens. The material on the lower screen is concentrated and then magnetically separated to remove impurities before being recycled as a heavy medium. The material under the lower screen is directly returned for reuse as a heavy medium.

[0030] According to some specific embodiments of the present invention, in step 4), the pulp concentration of the lead-zinc oxygen-sulfur mixed flotation is 30%-35%; the amount of lime is 1-3 kg / t; the amount of sodium sulfide, copper sulfate, sodium hexametaphosphate and water glass is 0.1-1 kg / t; and the amount of xanthate, black powder, ethyl thiocyanate, amine and phosphate ester is 20-100 g / t.

[0031] According to some specific embodiments of the present invention, the amine includes octadecylamine and / or dodecylamine; the phosphate ester includes monophosphate ester and / or diephosphate ester; and the foaming agent includes pine oil and / or MCC.

[0032] According to some specific embodiments of the present invention, in step 5), the de-drug treatment is carried out using a de-drug thickener or a scrubbing machine.

[0033] According to some specific embodiments of the present invention, in step 6), the amount of sodium sulfite and zinc sulfate used is 200-1000 g / t.

[0034] The beneficial effects of this invention are:

[0035] This invention proposes a beneficiation method for low-grade, difficult-to-process oxidized lead-zinc ore. It utilizes the density difference between the oxidized lead-zinc ore and the main gangue for two-stage separation: photoelectric separation and continuous hydrocyclone separation. Compared to traditional processes, the photoelectric separation process combines the screening after fine crushing with the screening before photoelectric separation. This not only reduces screening and improves the complex configuration of traditional photoelectric separation processes, but more importantly, it increases the separation capacity of the photoelectric separation, improves the waste rate, and reduces gangue entering the flotation system by 40-60%. This invention utilizes physical properties to pre-separate lead-zinc ore from major waste rocks such as quartz, calcite, and dolomite, effectively improving the feed grade of low-grade oxidized lead-zinc ore and reducing subsequent production costs.

[0036] This invention also realizes a system for the joint recovery of lead and zinc from "oxidized ore + sulfide ore". Addressing the challenges of low-grade oxidized lead and zinc ores, which are generally low in grade, have a variety of lead and zinc minerals, require large amounts of reagents, and have high recovery costs, this invention is the first to form a mixed flotation system that can simultaneously capture oxidized lead and zinc ores and sulfide lead and zinc ores by combining reagents. This greatly simplifies the flotation process and reduces investment and production costs.

[0037] This invention also utilizes a "dual activation system" (sodium sulfide + copper sulfate) and a three-stage structure of "mixing-flotation-re-separation" to enhance zinc activation and achieve lead-zinc separation using the system's reagents. The complementary use of sulfide-amine and sulfide-xanthate methods reduces slime interference, and the addition of phosphate esters further enhances zinc oxide flotation. Simultaneously, copper sulfate activation avoids the inhibition of sulfide mineral flotation by excessive sodium sulfide. The mixing-flotation stage greatly activates oxygen-sulfur lead-zinc ore, and combined with mixing-flotation and fine scavenging, it improves lead-zinc recovery and ensures concentrate grade. Reagent removal weakens the system's activity, reducing the difficulty of subsequent lead-zinc separation, while still retaining some of the original reagents to control the overall reagent usage. In the lead-zinc separation stage, sodium sulfite + zinc sulfate are used to strongly inhibit zinc, which synergizes with the preceding sulfide process and allows for overall control of inhibitor dosage.

[0038] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0039] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0040] Figure 1 This is a schematic diagram of the mineral processing method according to Embodiment 1 of the present invention.

[0041] Figure 2 This is a flowchart of photoelectric separation in traditional mineral processing methods.

[0042] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0043] Unless otherwise specified in the examples, the procedures should be performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Detailed Implementation

[0044] Example 1:

[0045] This embodiment is a mineral processing test conducted on the Huoshaoyun oxidized lead-zinc ore in Xinjiang Uygur Autonomous Region, including the following steps:

[0046] 1) The lead-zinc oxide ore is coarsely crushed and screened using a double-layer screen. The upper screen has a screen aperture of 40mm and the lower screen has a screen aperture of 10mm. The material with a particle size of 10-40mm will be obtained from the lower screen. The material is then separated by photoelectric separation to remove waste rock and obtain ore raw material with improved grade. The ore raw material is then finely crushed and screened and separated by photoelectric separation. The -10mm powder ore is sent to the powder ore bin. The material on the upper screen is then subjected to medium crushing and then returned to the screening, photoelectric separation and fine crushing to reach a particle size of -10mm before entering the powder ore bin.

[0047] 2) The fine ore in the ore bin is screened, with the particle size controlled at 0.3-0.5mm. The undersize material enters the grinding and classification process, while the oversize material is mixed with heavy media and fed into a hydrocyclone for separation. The heavy media and water are prepared by passing them through a medium and then fed into the hydrocyclone. The hydrocyclone produces overflow and undersize material.

[0048] The overflow is screened using a double-layer screen. The material over the upper screen is removed as waste rock, and the material over the lower screen is concentrated, then magnetically separated to remove impurities before being recycled as heavy medium. The material under the lower screen is directly returned for reuse as heavy medium.

[0049] The underflow sand is screened using upper and lower double-layer screens, with the particle size controlled at 0.3-0.5mm. The material oversizes enters the grinding and classification process. The material oversizes from the lower screen is concentrated, then magnetically separated to remove impurities before being recycled as heavy media. The material undersizes from the lower screen are directly returned as heavy media. In all the above steps, the lower screen aperture size is 0.1-0.3mm smaller than the upper screen aperture size.

[0050] After two stages of waste disposal, namely photoelectric separation and hydrocyclone separation, the material will enter step 3) grinding and classification.

[0051] As can be seen from steps 1) and 2), this invention utilizes the density difference between ore and gangue for photoelectric separation and hydrocyclone separation. The photoelectric separation process is shorter than traditional methods while increasing the amount of photoelectric separation, thus achieving physical pre-disposal of the ore. This reduces gangue entering the flotation system by 40-60%, significantly lowering the flotation load and effectively improving the grade of low-grade ore. This step differs from traditional simple photoelectric or heavy media separation; it fully utilizes the density difference between lead-zinc ore and gangue, as well as the characteristics of containing mud or easily generating mud, combining coarse crushing with a screening stage and photoelectric separation. This avoids the problem of severe mud formation caused by crushing and increases the proportion of photoelectric separation. The combination of photoelectric separation and heavy media separation forms two stages of pre-disposal, creating complementary coarse and fine disposal, effectively improving the disposal rate. This innovative introduction of a two-stage pre-enrichment process in low-grade oxidized lead-zinc ore breaks with convention in the crushing process, effectively avoiding mud formation while increasing the amount of disposable ore fed into the flotation system.

[0052] 3) Grinding and classification: The mud should be separated in advance to avoid serious over-grinding and reduce the production of secondary mud. The material that meets the target particle size should be subjected to lead-zinc-oxygen-sulfur mixed flotation. If the particle size of the material is larger than the target particle size, it needs to be ground and classified again.

[0053] 4) For materials meeting the particle size requirements, lead-zinc-oxygen-sulfur mixed flotation is performed. The pulp concentration for lead-zinc-oxygen-sulfur mixed flotation is 30%-35%. Lime, sodium sulfide, copper sulfate, sodium hexametaphosphate, water glass, xanthate, black powder, ethyl thiocyanate, amine, phosphate ester, and frother are added to the lead-zinc-oxygen-sulfur mixed flotation equipment. The amines include octadecylamine and / or dodecylamine; the phosphate esters include monophosphate and / or diephosphate; and the frother includes pine oil and / or MCC. Regarding dosage: the dosage of lime is 1-3 kg / t; the dosages of sodium sulfide, copper sulfate, sodium hexametaphosphate, and water glass are 0.1-1 kg / t; and the dosages of xanthate, black powder, ethyl thiocyanate, amine, and phosphate ester are 20-100 g / t.

[0054] Due to the synergistic effect of xanthates, black reagents, ethyl thiocyanates, amines, and phosphate esters, combinations of different functional groups are formed. Among them, amines and phosphate esters strongly adsorb lead oxide and zinc oxide, while xanthates and black reagents strongly collect lead sulfide and zinc sulfide. Ethiocyanates, as a surface-active bridging agent, enable the surfaces of multiple minerals to acquire similar hydrophobicity. This invention uses the combined activation effect of sodium sulfide and copper sulfate, which selectively sulfidates the surface of zinc oxide while simultaneously activating sphalerite and sulfidated zinc oxide. The combination of the two can make the surface electrical properties and activities of the two types of zinc minerals similar, thereby unifying the flotation conditions of zinc oxide and zinc sulfide, ensuring high recovery rate and feasibility of mixed flotation, shortening the process, reducing investment and reagent dosage, and enabling controllable mixed flotation of lead-zinc oxide-sulfide ores under a unified reagent system.

[0055] 5) After lead, zinc, oxygen, and sulfur co-flotation, a co-flotation cleaning and co-flotation scavenging process is configured. The specific structure can be adjusted, such as three cleaning and three scavenging processes, two cleaning and one scavenging processes, or two cleaning and two scavenging processes. The co-flotation cleaning and scavenging processes are returned in sequence. The co-flotation cleaning and scavenging processes are then subjected to co-flotation de-reagent treatment, which can be carried out using a de-reagent thickener or a scrubbing machine. The de-reagent treatment yields a co-flotation concentrate. Sodium sulfite and zinc sulfate are added to the co-flotation concentrate at a dosage of 200-1000 g / t each to separate lead and zinc, respectively.

[0056] This forms a three-stage flotation structure of "mixing flotation—removing reagents—re-separation," which is particularly suitable for typical oxygen-sulfur mixed lead-zinc ores both domestically and internationally. The mixing flotation stage promotes the simultaneous flotation of all lead and zinc minerals, improving recovery rate; the removal reagents stage slightly removes the composite reagents from the mixing flotation stage, avoiding mutual interference between the separation stages; in the re-separation stage, sodium sulfite and zinc sulfate are used to strongly suppress zinc, achieving highly selective lead-zinc separation, avoiding the problems of reagent interference and low recovery rates caused by the traditional step-by-step recovery process.

[0057] As can be seen from Example 1, this invention differs from the complex process of existing traditional processes involving "segmented flotation, lead followed by zinc, sulfur followed by oxygen, plus multi-stage enhanced activation and inhibition." The method of this invention effectively shortens the process, reduces investment, decreases reagent usage, avoids mud-forming and crushing, and eliminates the need for pre-desliming throughout the entire process of crushing, optical separation, hydrocyclone separation, pre-inspection grinding and classification, oxygen-sulfur mixed flotation, and reagent removal and separation. It effectively solves the problems encountered in the beneficiation of typical low-grade oxidized lead-zinc ores. Reagent consumption is reduced by 20-40%, lead-zinc recovery rate is increased by 5-20%, construction costs are reduced by 10-50%, and the stability of the flotation system is significantly improved. It is particularly suitable for large-scale application in low-grade, highly oxidizing lead-zinc mines.

[0058] The following are experimental data from several embodiments of the present invention, as well as comparative data:

[0059] From this, we can more intuitively see that compared with the prior art, the present invention not only shortens the process flow and significantly reduces reagent costs, but also significantly improves the recovery rates of lead and zinc, realizing the comprehensive utilization of low-grade and difficult-to-process oxidized lead-zinc ore.

Claims

1. A beneficiation method for low-grade, difficult-to-process oxidized lead-zinc ore, characterized in that, Includes the following steps: 1) The lead-zinc oxide ore is crushed and screened to obtain materials with a particle size of 10-40mm. Photoelectric separation is used to remove waste rock and obtain ore raw materials with improved grade. The ore raw materials are then finely crushed and screened and photoelectric separated. The +40mm material is medium crushed and the -10mm fine ore is fed into the fine ore bin. 2) The powdered ore in the powder ore bin is screened, with the oversize material being separated by a hydrocyclone and the undersize material entering the grinding and classification process; the separation product of the hydrocyclone is screened, and the overflow is screened by upper and lower double-layer screens, with the oversize material of the upper screen being removed as waste rock; the undersize sand is screened by upper and lower double-layer screens, with the oversize material of the upper screen entering the grinding and classification process. 3) After the material in step 2) enters the grinding and classification process, the material that meets the particle size requirements is obtained; 4) The material obtained in step 3) that meets the particle size requirements is subjected to lead-zinc-oxygen-sulfur mixed flotation. Lime, sodium sulfide, copper sulfate, sodium hexametaphosphate, water glass, xanthate, black powder, ethyl thiocyanate, amine, phosphate ester, and foaming agent are added to the lead-zinc-oxygen-sulfur mixed flotation equipment. 5) After lead, zinc, oxygen and sulfur are mixed and floated, mixed flotation and cleaning and mixed flotation and scavenging are configured. The mixed flotation and cleaning and scavenging are returned in sequence. The mixed concentrate after mixed flotation and cleaning is subjected to mixed flotation and de-reagent treatment to obtain the de-reagented mixed concentrate. 6) Sodium sulfite and zinc sulfate are added to the mixed concentrate obtained in step 5) to perform lead-zinc separation treatment, and lead concentrate and zinc concentrate are obtained respectively.

2. The mineral processing method according to claim 1, characterized in that, In step 1), the +40mm material is subjected to medium crushing, sieved, and then enters the photoelectric sorting.

3. The mineral processing method according to claim 1, characterized in that, Step 1) Use an upper and lower double-layer sieve to obtain materials with a particle size of 10-40mm; Step 2) The lower sieve of the upper and lower double-layer sieve has a screen hole size that is 0.1-0.3mm smaller than that of the upper sieve.

4. The mineral processing method according to claim 1, characterized in that, In step 2), the powdered ore in the powder ore bin and the hydrocyclone product are screened, and the screening particle size is controlled at 0.3-0.5mm.

5. The mineral processing method according to claim 1, characterized in that, Step 3) During classification, materials larger than the target particle size should be ground and then returned to classification.

6. The mineral processing method according to claim 1, characterized in that, Step 3) involves screening the hydrocyclone separation products: The overflow of the hydrocyclone is screened using upper and lower double-layer screens. The material over the upper screen is removed as waste rock, and the material over the lower screen is concentrated, then magnetically separated to remove impurities and recovered as heavy medium. The material under the lower screen is directly returned for reuse as heavy medium. The sludge from the hydrocyclone is screened using upper and lower double-layer screens. The material on the lower screen is concentrated and then magnetically separated to remove impurities before being recycled as a heavy medium. The material under the lower screen is directly returned for reuse as a heavy medium.

7. The mineral processing method according to claim 1, characterized in that, In step 4), the pulp concentration of the lead-zinc oxygen-sulfur mixed flotation is 30%-35%; the amount of lime used is 1-3 kg / t; the amount of sodium sulfide, copper sulfate, sodium hexametaphosphate and water glass used is 0.1-1 kg / t; and the amount of xanthate, black powder, ethyl thiocyanate, amine and phosphate ester used is 20-100 g / t.

8. The mineral processing method according to claim 7, characterized in that, The amine includes octadecylamine and / or dodecylamine; the phosphate ester includes monophosphate ester and / or diester phosphate ester; the foaming agent includes pine oil and / or MCC.

9. The mineral processing method according to claim 1, characterized in that, In step 5), the de-drug treatment is carried out using a de-drug thickener or a scrubbing machine.

10. The mineral processing method according to claim 1, characterized in that, In step 6), the amount of sodium sulfite and zinc sulfate used is 200-1000 g / t.

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