Efficient combined collecting agent and beneficiation method for refractory Carlin type gold ore

Abstract

The invention discloses an efficient combined collecting agent and beneficiation method for refractory Carlin type gold ores, ethylenediamine tetramethylenephosphonic acid and sodium butyl xanthate are adopted as the combined collecting agent, ethylenediamine tetramethylenephosphonic acid has high dispersing capacity, dispersion of fine particles in ore pulp can be promoted, and the concentration of the fine particles in the ore pulp can be increased; the action site of the collecting agent sodium butyl xanthate is prevented from being occupied; meanwhile, ethylenediamine tetramethylenephosphonic acid has high complexing capacity on ions, such as Fe and Mg, which influence the adsorption of the agent, and a product after complexing the Fe and Mg ions can be dissolved in water, so that the effect of cleaning the surfaces of minerals can be achieved, and acting sites are provided for selective adsorption of the collecting agent. The combined collecting agent plays a good synergistic effect, and the aim of improving the recovery rate and the enrichment ratio of gold in the flotation process of the refractory Carlin type gold ore can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of mineral processing, and in particular to a high-efficiency combined collector and a beneficiation method for refractory Carlin-type gold ore. Background Art

[0002] Carlin-type gold deposits are named after the town of Carlin in Nevada, USA, where they were discovered in the 1960s (Hofstra AH. Characteristics and models from Carlin-type gold deposits (Chapter 5) [M]. Society of Economic Geologists Reviews, 2000, 13). They are primarily distributed in Nevada and Utah in the United States, and in the gold mining belts of Yunnan, Guizhou, and Guangxi Zhuang Autonomous Region in China, as well as in the gold mining areas at the junction of Sichuan, Shanxi, and Gansu provinces (Sun Zhongmei. Research and Application of Improving the Flotation Efficiency of Gold-Loaded Pyrite [D]. Beijing: University of Science and Technology Beijing, 2015). Data from the United States Geological Survey indicate that approximately a quarter of the world's gold comes from refractory Carlin-type gold deposits (Kasymova D. Carbon footprint of gold recovery from refractory ore in Russia [D]. Russia, Lappeenranta University of Technology, 2019). With the mining and utilization of easily tractable gold ores, the proportion of Carlin-type gold deposits has increased annually.

[0003] During the mineralization process of Carlin-type gold deposits, the ore-forming hydrothermal fluids infiltrate the silty dolomite, increasing the content of carbonate minerals such as dolomite (Hassas B V. Fundamental Surface Chemistry Aspects of Auriferous Pyrite Flotation with Carbon Dioxide and Nitrogen [D]. The University of Utah, 2018.). This results in high costs and low enrichment ratios for direct pressure leaching of Carlin-type gold deposits (a commonly used and efficient method). Therefore, removing dolomite by flotation separation before leaching is the key to reducing leaching costs and improving separation efficiency.

[0004] Currently, the following high-efficiency flotation methods are commonly used in the industry for Carlin-type gold ores: N2 / CO2 flotation, elevated temperature flotation, microbubble flotation, oil-agglomeration flotation, and the addition of various conditioning agents. However, these methods do not significantly improve the gold enrichment ratio and recovery rate in treating difficult-to-separate Carlin-type gold ores. For example, in the industrial flotation process of the Sebang Carlin-type gold mine of Chifeng Jilong Mining Co., Ltd., the Au enrichment ratio is only about 2.5. Furthermore, Miller et al. (Ozun S, Hassas BV, Miller J D. Collectorless flotation of oxidized pyrite [J]. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2019, 561(349-56).) demonstrated in industrial practice in Newmount that N2 / CO2 flotation has limited effect on improving the flotation recovery rate of Carlin-type gold ores with a high content of oxidized fine particles.

[0005] Conventional flotation methods are difficult to achieve high recovery rates because the gold in difficult-to-separate Carlin-type gold deposits is mostly present in the pyrite lattice in the form of fine sulfur-coated gold (Zhao Haiping, Liu Jingzhi, Hu Xueping, et al. Application of sodium aminophosphate in the efficient separation of Carlin-type gold deposits [J]. Nonferrous Metals Engineering, 2024, 14(6): 91-98.). Therefore, Carlin-type gold deposits usually require fine grinding to achieve better dissociation of gold-bearing minerals. However, fine grinding will significantly increase the content of fine particles in the slurry. Fine particles have a large surface energy and can non-selectively cover the mineral surface, thereby affecting the selective adsorption of the collector.

[0006] In summary, developing high-efficiency reagents with dispersed fine particles, clean mineral surface action sites, and promote selective adsorption of conventional collectors is an effective way to improve the recovery rate and enrichment ratio of gold in difficult-to-select Carlin-type gold ores. However, the reagent formulas currently disclosed on the market, such as sodium carbonate + sodium hexametaphosphate + water glass + copper sulfate adjuster (Chinese patent application CN103433143A), ethylenediamine phosphate + butylamine black medicine + aniline black medicine + acetone (Chinese patent application CN107744884A), or xanthate + thiocarbamate collectors (Huang Qingqi, Liao Xingjin, Wei Lianjun, et al. Experimental study on high-efficiency flotation recovery of gold from carbonaceous Carlin gold mines in Guangxi [J]. Hunan Nonferrous Metals, 2022, 38(5): 16-19.) have disadvantages such as low gold recovery rate and enrichment ratio, complex reagent formula, and difficulty in degradation in the flotation process of difficult-to-select Carlin-type gold ores. Therefore, high-efficiency recovery reagents for difficult-to-select Carlin-type gold ores still need to be further optimized. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the present invention aims to provide a high-efficiency combined collector and mineral processing method for refractory Carlin-type gold ore, thereby improving the gold recovery rate and separation efficiency of refractory Carlin-type gold ore.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A high-efficiency combined collector for difficult-to-select Carlin-type gold ore is characterized by comprising 10,800-12,800 parts by weight of ethylenediaminetetramethylenephosphoric acid and 2,250-2,790 parts by weight of sodium butyl xanthate.

[0010] The present invention also provides a beneficiation method for recovering refractory Carlin-type gold ore using the above-mentioned high-efficiency combined collector, comprising the following steps:

[0011] S1, crushing the raw ore;

[0012] S2, mixing the crushed ore obtained in step S1 with water and grinding the ore to obtain a floatable product;

[0013] S3. The floatable product obtained in step S2 is subjected to three-stage full open-circuit flotation; before each stage of flotation, the high-efficiency combined collector is pre-added, and after stirring and slurrying, flotation is performed to obtain concentrate and tailings; the tailings remaining in each stage of flotation are fed to the next stage of flotation, and the concentrates obtained in each stage of flotation are mixed to obtain the final Carlin-type gold concentrate, and the tailings remaining after the third stage of flotation are the final tailings; before the first stage of flotation, a frother is added after adding the high-efficiency combined collector.

[0014] Furthermore, in step S1, the raw ore is crushed to a particle size of ≤2 mm.

[0015] Furthermore, in step S2, the grinding is carried out in a ball mill with an iron ball medium having a filling rate of 30% for 10 minutes, and the portion of the obtained floatable product with a particle size of ≤30 μm accounts for 85-90% of the total mass of the floatable product.

[0016] Furthermore, in step S3, in each flotation stage, the pulp mass concentration is 30-35%, and the pulp pH is maintained in an alkaline environment of 9-9.5.

[0017] Furthermore, the total dosage of the high-efficiency combined collector in all flotation stages includes 10,800-12,800 g / t of ore dry weight of ethylenediaminetetramethylenephosphoric acid and 2,250-2,790 g / t of ore dry weight of sodium butyl xanthate.

[0018] The beneficial effects of the present invention are:

[0019] The present invention addresses the problem that traditional collectors have low recovery rates and poor separation efficiency (low enrichment ratio) when recovering gold from refractory Carlin-type gold mines. Ethylenediaminetetramethylenephosphoric acid and sodium butyl xanthate are used as combined collectors to enhance the dispersion effect of fine-particle minerals and promote the selective adsorption of collectors, thereby improving the recovery rate and enrichment ratio of gold in refractory Carlin-type gold mines. Specifically, ethylenediaminetetramethylenephosphoric acid has a strong dispersing ability, which can promote the dispersion of fine particles in the ore pulp and avoid occupying the action sites of the collector sodium butyl xanthate; at the same time, ethylenediaminetetramethylenephosphoric acid has a strong complexing ability for ions such as Fe and Mg that affect the adsorption of the agent, and the product after complexing Fe and Mg ions is soluble in water, which can play a role in cleaning the mineral surface and provide an action site for the selective adsorption of the collector. The combined collector in the present invention has exerted a good synergistic effect and can achieve the goal of improving the recovery rate and enrichment ratio of gold in the flotation process of refractory Carlin-type gold mines. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a flow chart for implementing the methods of Examples 1-3 of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings. It should be noted that this embodiment is based on the technical solution and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to this embodiment.

[0022] Example 1

[0023] This embodiment provides a mineral processing method using a high-efficiency combined collector for refractory Carlin-type gold ore. Figure 1 As shown, the following steps are included:

[0024] S1. Use a laboratory jaw crusher to crush the raw ore to a particle size of ≤2mm, mix it evenly and set aside.

[0025] S2. 500 g of the mixed sample was mixed with 315 mL of water and placed in a ball mill with an iron ball medium having a filling rate of 30%. The ore was ground for 10 minutes to obtain a floatable product. The portion of the floatable product with a particle size of ≤30 μm accounted for 87% of the total floatable product.

[0026] S3. The floatable product obtained in step S2 is subjected to three stages of open-circuit flotation. The tailings remaining from each stage of flotation are fed to the next stage of flotation. The concentrates obtained from each stage of flotation are mixed to form the final concentrate. The tailings remaining after the third stage of flotation are the final tailings.

[0027] Before each flotation stage, a high-efficiency combined collector was added for stirring and slurry preparation. The first stage contained 6400 g / t of EDTP and 1350 g / t of sodium butyl xanthate, with stirring lasting 5 minutes. The second and third stages used the same amount of combined collector, containing 2800 g / t of EDTP and 450 g / t of sodium butyl xanthate, for 2 minutes. The duration of each flotation stage was 6 minutes.

[0028] During each flotation stage, the pH value of the pulp was maintained at an alkaline environment of 9, and the pulp mass concentration was approximately 32%.

[0029] In this embodiment, before the first stage of flotation, after adding the high-efficiency combined collector, a frother 2# oil is added in an amount of 40 g / t dry weight of the ore. After adding the frother, stirring is performed for 1 minute.

[0030] In this embodiment, the total dosage of the high-efficiency combined collector used in the three flotations is 14250 g / t of the dry weight of the ore, which includes 12000 g / t of ethylenediaminetetramethylenephosphoric acid and 2250 g / t of sodium butyl xanthate.

[0031] Example 2

[0032] The method of this embodiment is basically the same as that of Example 1, with the main difference being that the total dosage of the high-efficiency combined collector is 15,500 g / t of the dry weight of the ore, which includes 12,800 g / t of ethylenediaminetetramethylenephosphoric acid and 2,700 g / t of sodium butyl xanthate.

[0033] The amount of the high-efficiency combined collector used in the first stage of flotation is the same as that in Example 1, while the high-efficiency combined collectors used in the second and third stages both contain 3200 g / t of ethylenediaminetetramethylenephosphoric acid (EDTP) and 675 g / t of sodium butyl xanthate (SBX).

[0034] Example 3

[0035] The method of this embodiment is basically the same as that of Example 1, with the main difference being that the total dosage of the high-efficiency combined collector is 13590 g / t of the dry weight of the ore, which includes 10800 g / t of ethylenediaminetetramethylenephosphonic acid and 2790 g / t of sodium butyl xanthate.

[0036] The dosage of the high-efficiency combined collector used in the first stage of flotation is the same as that in Example 1, while the high-efficiency combined collector used in the second and third stages of flotation both contains 2200 g / t of ethylenediaminetetramethylenephosphoric acid and 720 g / t of sodium butyl xanthate.

[0037] Comparative Example 1

[0038] A high-grade Carlin-type gold ore contains approximately 4.33 g / t gold and 2.96% MgO. The ore's characteristics are as follows: ① Gold is primarily present in the pyrite as fine, invisible particles, requiring fine grinding for optimal separation; ② The finely ground product contains a high concentration of fine particles, resulting in poor separation efficiency between useful and gangue minerals and low gold recovery. The gold in the ore is primarily contained in the pyrite. Gangue minerals are primarily dolomite and quartz. Due to the non-selective covering of fine particles on the mineral surface, conventional collector flotation of this Carlin-type gold ore results in poor concentrate separation efficiency and low gold recovery.

[0039] The ore was processed by the ore dressing method in Example 1, and the obtained indicators are shown in Table 1.

[0040] Using the same ore as above, the high-efficiency combined collector in the method of Example 1 was replaced by the conventional collector sodium butyl xanthate as comparative experiment 1. The total dosage of the conventional collector sodium butyl xanthate was 5000 g / t of the dry weight of the ore (the dosage of sodium butyl xanthate in the first, second and third flotation processes was 2500 g / t, 1500 g / t and 1000 g / t, respectively. When sodium butyl xanthate was used as a conventional collector, its dosage was usually 3000 g / t of the dry weight of the ore. In comparative experiment 1, it was increased to below 5000 g / t of the dry weight of the ore. Continuously increasing the dosage of sodium butyl xanthate had no effect on the data indicators).

[0041] The process indicators of Example 1 and Comparative Experiment 1 are shown in Table 1 (the grade and recovery rate of magnesium oxide are used to replace the grade and recovery rate of gangue minerals such as dolomite):

[0042] Table 1

[0043]

[0044] As shown in Table 1, Example 1 achieved excellent mineral processing performance. Compared with Comparative Experiment 1, the Au grade in the concentrate increased by 7.84 g / t, and the Au recovery rate increased by 40.01%. The application of the high-efficiency combined collector doubled the gold grade and recovery rate in the flotation concentrate. Furthermore, the application of the high-efficiency combined collector reduced the MgO grade by 0.6% and the MgO recovery rate by 12.80%, demonstrating that the high-efficiency combined collector significantly improved ore separation efficiency.

[0045] Comparative Example 2

[0046] A low-grade Carlin-type gold ore contains approximately 1.23 g / t gold and 10.55% MgO. The ore's characteristics are as follows: ① The gold is primarily present in the pyrite as fine, invisible gold particles, requiring fine grinding for optimal separation; ② The high dolomite content causes heterogeneous agglomeration between the dolomite and oxidized pyrite, resulting in poor separation efficiency between useful and gangue minerals and low gold recovery. The gold in the ore is primarily present in the pyrite as invisible gold. The gangue minerals are primarily dolomite. Using conventional collectors for flotation of this Carlin-type gold ore results in poor concentrate separation efficiency and low gold recovery.

[0047] The ore was processed by the ore dressing method in Example 2, and the obtained indicators are shown in Table 2.

[0048] Using the same ore as above, comparative experiment 2 was conducted by replacing the high-efficiency combined collector in the method of Example 2 with the conventional collector sodium butyl xanthate. The total dosage of the conventional collector sodium butyl xanthate was 5000 g / t of the dry weight of the ore (the dosage of sodium butyl xanthate in the first, second and third flotation processes was 2500 g / t, 1500 g / t and 1000 g / t, respectively. The dosage of sodium butyl xanthate as a conventional collector is usually below 3000 g / t of the dry weight of the ore. In comparative experiment 2, it was increased to 5000 g / t of the dry weight of the ore. Continuing to increase the dosage of sodium butyl xanthate had no effect on the data indicators).

[0049] The process indicators of Example 2 and Comparative Experiment 2 are shown in Table 2 (the grade and recovery rate of gangue minerals such as dolomite are replaced by the grade and recovery rate of magnesium oxide):

[0050] Table 2

[0051]

[0052] As shown in Table 2, Example 2 achieved superior beneficiation performance. Compared with Comparative Experiment 2, the Au grade in the concentrate increased by 1.58 g / t, and the Au recovery rate increased by 18.27%. The application of the high-efficiency combined collector achieved the desired goals of increasing the gold grade and recovery rate in the flotation concentrate. Furthermore, the application of the high-efficiency combined collector reduced the MgO grade by 2.6% and the MgO recovery rate by 13.75%, demonstrating that the high-efficiency combined collector significantly improved ore separation efficiency.

[0053] Those skilled in the art can make various corresponding changes and modifications based on the above technical solutions and concepts, and all of these changes and modifications should be included in the scope of protection of the claims of the present invention.

Claims

1. A highly efficient combined collector for refractory Carlin-type gold ore, characterized in that: The invention comprises 10800-12800 parts of ethylenediaminetetramethylenephosphoric acid and 2250-2790 parts of sodium butyl xanthate in parts by weight.

2. A beneficiation method for recovering refractory Carlin-type gold ore using the high-efficiency combined collector according to claim 1, characterized in that: The steps include: S1, crushing the raw ore; S2, mixing the crushed ore obtained in step S1 with water and grinding the ore to obtain a floatable product; S3. The floatable product obtained in step S2 is subjected to three-stage full open-circuit flotation; before each stage of flotation, the high-efficiency combined collector is pre-added, and after stirring and slurrying, flotation is performed to obtain concentrate and tailings; the tailings remaining in each stage of flotation are fed to the next stage of flotation, and the concentrates obtained in each stage of flotation are mixed to obtain the final Carlin-type gold concentrate, and the tailings remaining after the third stage of flotation are the final tailings; before the first stage of flotation, a frother is added after adding the high-efficiency combined collector.

3. The method according to claim 2, characterized in that In step S1, the raw ore is crushed to a particle size of ≤2 mm.

4. The method according to claim 2, characterized in that In step S2, the grinding is carried out in a ball mill with an iron ball medium having a filling rate of 30% for 10 minutes, and the portion of the obtained floatable product with a particle size of ≤30 μm accounts for 85-90% of the total mass of the floatable product.

5. The method according to claim 2, characterized in that In step S3, in each flotation stage, the pulp mass concentration is 30-35%, and the pulp pH is maintained in an alkaline environment of 9-9.

5.

6. The method according to claim 2, characterized in that The total dosage of the high-efficiency combined collector in all flotation stages includes 10,800-12,800 g / t of ore dry weight and 2,250-2,790 g / t of butyl sodium xanthate.

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