A rapid flotation process for efficient recovery of coarse copper slag

Abstract

This invention discloses a rapid flotation process for efficiently recovering coarse copper slag, comprising the following steps: (1) crushing and ball milling the copper slag, adding grinding aids and oxidants during grinding to obtain the slurry required for rapid flotation; (2) adding collectors and frothers for rapid flotation to obtain coarse copper sulfide; (3) adding modifiers, collectors and frothers to the remaining slurry for flotation, combining the roughing product and the coarse copper sulfide obtained by rapid flotation into copper concentrate; (4) continuing to add modifiers, collectors and frothers to the remaining roughing slurry for flotation, returning the middlings obtained by scavenging to the roughing operation, and filtering and drying the remaining slurry as tailings. This invention improves the liberation of copper slag and the physicochemical properties of the surface of copper-containing particles in the slag by adding grinding aids and oxidants. Rapid flotation can recover a portion of copper sulfide concentrate before roughing, increasing the recovery efficiency of fine copper particles in subsequent operations.

Description

Technical Field

[0001] This invention belongs to the field of resource recycling technology, and in particular relates to a rapid flotation process for efficiently recovering coarse copper slag. Background Technology

[0002] Copper slag, as a man-made mineral, often contains higher grades of valuable metals than natural copper ore. However, the complex intergrowth relationships and diverse mineral types within its tailings make the recovery of valuable resources extremely difficult. Mineral processing and separation are among the main processes for recovering copper minerals from copper slag. This process separates valuable minerals from gangue minerals based on the different hydrophilic and hydrophobic properties of the valuable metals. Copper slag processed using this method typically has specific requirements regarding the particle size and hydrophilic / hydrophobic properties of the valuable minerals. Therefore, flotation is often used to process slowly cooled flash slag and converter copper slag. Copper matte has a low melting point. After slow cooling, the copper matte can aggregate into relatively coarse particles. However, due to prolonged exposure to air, some of the copper matte will oxidize to copper oxide. Since copper oxide is a hydrophilic mineral, flotation is difficult, affecting the overall copper recovery efficiency.

[0003] Currently, to address the issue of uneven copper particle size and complex occurrence states in copper slag, most companies control the grinding-flotation process, using multiple grinding-flotation stages to recover copper particles of different sizes. However, multiple grinding stages make the entire recovery process cumbersome and increase equipment costs and energy consumption. Summary of the Invention

[0004] This invention addresses the problems existing in the prior art by providing a rapid flotation process for efficiently recovering coarse copper slag. During the grinding process, this method utilizes the stronger reducing power of Cu(I) ions than S ions, using an oxidizing agent to oxidize Cu(I) on the surface of the copper slag to Cu(II), while the copper matte remains unoxidized. In the flotation process, the copper slag is first subjected to a high-slurry-concentration rapid flotation to recover the fast-floating coarse copper matte particles, reducing the flotation pressure on subsequent copper particles. Then, a sulfiding agent is used to sulfide and recover the remaining copper minerals whose surface has been oxidized. This achieves highly efficient recovery of copper-containing minerals from the copper slag.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] This invention provides a rapid flotation process for efficiently recovering coarse copper slag, comprising the following steps:

[0007] (1) Grinding: The copper slag is crushed and ball-milled. Grinding aids and oxidants are added during grinding to obtain the slurry required for rapid flotation.

[0008] (2) Rapid flotation: Add collectors and frothers to carry out rapid flotation to obtain coarse copper sulfide particles;

[0009] (3) Roughing: Add modifier, collector and frother to the remaining slurry for flotation, and combine the roughing product and the coarse copper sulfide obtained by rapid flotation into copper concentrate;

[0010] (4) Scavenging: Add modifiers, collectors and frothers to the remaining slurry from the roughing process for flotation. The middlings obtained from scavenging are returned to the roughing process, and the remaining slurry is filtered, dried and treated as tailings.

[0011] During the cooling process of copper slag, copper-containing minerals exist in different states. Copper sulfide, with its low melting point and high density, can settle and aggregate into large copper particles during solidification. Collectors can easily adhere to these copper sulfide minerals, making them hydrophobic and allowing them to float with the foam. Copper oxide, on the other hand, has a strong hydrophilic surface, requiring the use of a sulfiding agent to sulfide its surface, forming copper sulfide species that readily interact with the collector, before recovery. However, copper in copper slag exists in multiple valence states. Cu(II) has a strong affinity for sulfide ions and can be recovered using a conventional sulfidation-flotation system. Cu(I) has a weak affinity for sulfide ions and requires oxidation or control of the pulp potential to enhance its surface activity. It can be seen that copper-containing minerals in copper slag have different types and particle sizes, and the flotation conditions differ for different particles. This invention adds an oxidant during grinding to first convert the difficult-to-sulfurize Cu(I) into sulfurizable Cu(II). The easily floatable coarse-grained copper sulfide is then recovered through rapid flotation with high slurry concentration. The remaining slurry is then subjected to sulfidation-flotation, thereby achieving efficient recovery of various copper-containing minerals in the copper slag.

[0012] Preferably, in step (1), the copper slag is wet-milled using a ball mill, and the grinding fineness is such that the content of -0.074mm particle size is more than 90%.

[0013] Preferably, one or more of the following oxidants are added during the grinding process: hydrogen peroxide, calcium peroxide, calcium hypochlorite, etc.

[0014] Preferably, the volume fraction of hydrogen peroxide added is 1%-30%, more preferably, the volume fraction of hydrogen peroxide added is 1%-5%;

[0015] More preferably, sodium carbonate is added simultaneously during grinding, with an addition amount of 200-1600 g / t compared to the treated ore sample;

[0016] Sodium carbonate plays a crucial role in ore grinding, both by adjusting the pH of the slurry and by aiding grinding. The adsorption of sodium carbonate on minerals alters the surface potential, causing fine mineral particles to acquire similar charges and repel each other, effectively reducing over-grinding during the grinding process.

[0017] Preferably, in step (2), one or more of xanthates, black powders, and sulfur-nitrogen compounds are added as collectors;

[0018] Preferably, in step (2), the rapid flotation should control the pulp mass concentration to be 30%-50% and the flotation time to be 1-2 minutes;

[0019] Coarse-grained single copper particles and fine-grained intercalated copper particles exhibit different flotation kinetics. Coarse-grained single copper particles have a faster flotation rate and higher recovery rates at high pulp concentrations. Before conventional flotation, rapid recovery of coarse-grained copper slag with a collector can reduce competition for adsorption with the collector on difficult-to-react copper particles during subsequent flotation operations. Furthermore, coarse-grained single copper particles are predominantly composed of copper sulfide ores, and the subsequent use of sulfiding agents can inhibit the flotation of sulfide ores.

[0020] Preferably, the slurry concentration in steps (3) and (4) is 20%-30%;

[0021] Preferably, the modifiers added in steps (3) and (4) include a sulfiding agent, an activator, an inhibitor, or a combination thereof; more preferably, sodium sulfide, the sulfiding agent, and copper sulfate, the activator, are mixed in a 1:1 ratio.

[0022] Compared with the prior art, the advantages of the present invention are as follows:

[0023] 1. Micro-sulfidation of copper slag during grinding oxidizes Cu(I) to Cu(II), thereby improving the sulfidation flotation efficiency of copper oxide ore.

[0024] 2. Oxidants in the slurry can also increase the slurry potential and improve the electrochemical environment for sulfide ore flotation.

[0025] 3. Rapid flotation separates easily floatable coarse copper sulfide particles from difficult-to-float copper particles, avoiding competitive adsorption of the collector by the easily floatable and difficult-to-float particles, thus improving the recovery efficiency of difficult-to-float copper minerals.

[0026] 4. By recovering coarse copper sulfide particles in advance, the inhibition of sulfide ore by sulfiding agent is reduced. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a process flow diagram of the method of the present invention. Detailed Implementation

[0029] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0031] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0032] Example 1:

[0033] The chemical composition of the copper slag in Example 1 is shown in Table 1:

[0034] Table 1: Chemical composition analysis of copper slag

[0035]

[0036] A method for recovering copper from low-grade copper smelting slag, comprising the following specific steps:

[0037] (1) The copper slag was ball-milled to a particle size of -0.074 mm accounting for 90%. Hydrogen peroxide and sodium carbonate were added during the grinding process. The amount of hydrogen peroxide was 100 g / t and the amount of sodium carbonate was 600 g / t.

[0038] (2) Adjust the pulp concentration to 40%, add 200g / t xanthate and stir in the flotation machine for 3 minutes, then add 30g / t terpineol as a frother and stir for 1 minute, and then perform rapid flotation for 2 minutes to obtain coarse concentrate;

[0039] (3) Adjust the mass concentration of the remaining slurry to 25%, mix sodium sulfide and copper sulfate as a mixing modifier in a 1:1 ratio and add 200g / t as a modifier for 3min, then add 150g / t of butyl xanthate for 3min, add 20g / t of terpineol for 1min and then perform roughing operation for 3min to obtain roughing concentrate and remaining slurry. Mix the roughing concentrate with the coarse concentrate obtained by rapid flotation as the final concentrate product.

[0040] (4) The remaining slurry undergoes two-stage scavenging operations. In the first scavenging operation, 100 g / t of mixing modifier is added and reacted for 3 min, followed by 75 g / t of butyl xanthate and reacted for 3 min, then 10 g / t of terpineol and reacted for 1 min, followed by scavenging for 3 min. In the second scavenging operation, 50 g / t of mixing modifier is added and reacted for 3 min, followed by 30 g / t of butyl xanthate and reacted for 3 min, then 5 g / t of terpineol and reacted for 1 min, followed by scavenging for 3 min. The middlings from the two scavenging operations are returned to the next flotation stage in sequence.

[0041] The indicators of the concentrate products obtained by flotation according to the above process and reagent dosage are shown in Table 2.

[0042] Table 2: Copper slag flotation parameters under different processes

[0043] Test Procedure Copper grade Copper recovery rate Example 1 Standard Procedure 25.36％ 90.23％ Comparative Example 1 No oxidizing agent 20.52％ 75.03％ Comparative Example 2 Non-fast flotation 27.33％ 82.31％ Comparative Example 3 Grinding and then oxidation 24.26％ 87.94％

[0044] Comparative Example 1:

[0045] No oxidant was added during the grinding process. The concentrate product indicators obtained by flotation according to the above process and reagent dosage are shown in Table 1 (Comparative Example 1).

[0046] Comparative Example 2:

[0047] Without performing a rapid flotation step on the grinding product, the concentrate product indicators obtained by flotation according to the above process and reagent dosage are shown in Table 1 (Comparative Example 2).

[0048] Comparative Example 3:

[0049] An oxidant was added to the remaining slurry after rapid flotation and acted for 3 minutes. Following the above process and reagent dosage, the concentrate product indicators obtained by flotation are shown in Table 1 (Comparative Example 3).

Claims

1. A process for fast flotation of high recovery of coarse copper slag, characterized in that: Includes the following steps: (1) Grinding: The copper slag is crushed and ball-milled. Grinding aids and oxidants are added during grinding to obtain the slurry required for rapid flotation. (2) Rapid flotation: Add collectors and frothers to carry out rapid flotation to obtain coarse copper sulfide particles; (3) Roughing: Add modifier, collector and frother to the remaining slurry for flotation, and combine the roughing product and the coarse copper sulfide obtained by rapid flotation into copper concentrate; (4) Scavenging: Add modifiers, collectors and frothers to the remaining slurry from the roughing process for flotation. The middlings obtained from scavenging are returned to the roughing operation, and the remaining slurry is filtered, dried and treated as tailings. The oxidant is hydrogen peroxide, with a mass fraction of 0.1%-30%. The amount added is based on the reference of oxidizing Cu(I) on the mineral surface to Cu(II) without oxidizing copper sulfide to the ideal value. Sodium carbonate is used as the grinding aid in the grinding process, and its addition amount is 200-1600g / t; The rapid flotation process has a flotation time of 1-2 minutes and a pulp mass concentration of 30%-50%. The pH adjusters include hydrochloric acid, sulfuric acid, sodium hydroxide, and sodium carbonate; the sulfiding agents include sodium sulfide and sodium thiosulfate; the activator is copper sulfate; and the inhibitors include inhibitors for hematite and silicate minerals, namely starch, sodium hexametaphosphate, water glass, and lime.

2. The rapid flotation process for efficient recovery of coarse copper slag according to claim 1, characterized in that: The collecting agent includes one or more of xanthates, nitric oxides, and sulfur-nitrogen compounds.

Images