Two-stage leaching system

Abstract

The utility model discloses a two -segment formula leaching system belongs to the technical field of hydrometallurgy. The system includes the connection of one segment leaching groove, thickener, two -segment formula leaching groove and filter press in proper order. One segment leaching groove discharges and connects thickener, and thickener overflow is connected to purification groove, and the underflow enters two -segment formula leaching groove and carries out high -acid leaching. The slurry after two -segment formula leaching is filtered through filter press, and the obtained filtrate is refluxed to one segment leaching groove and is recycled as the bottom liquid, and the waste residue is discharged. The utility model discloses the core lies in through setting two -segment formula leaching procedure and combining filtrate reflux cycle, has realized the internal circulation of acid liquor, has reduced the consumption of sulfuric acid and neutralizing agent cost significantly, and has improved the leaching rate of low -grade manganese ore. The system simple structure does not need high temperature and high pressure condition, is applicable to large -scale industrial application, is especially suitable for processing low -grade manganese carbonate ore.

Description

Technical Field

[0001] This utility model relates to the field of hydrometallurgical technology, specifically to a system for mineral leaching, which is particularly suitable for a two-stage leaching system for leaching low-grade manganese carbonate ore. Background Technology

[0002] Manganese is an important strategic metal resource, widely used in industries such as steel, chemicals, and batteries. With the increasing depletion of high-quality manganese ore resources, the efficient utilization of low-grade and difficult-to-process manganese ores has become an inevitable trend in industry development. Hydrometallurgy is an important method for processing low-grade manganese ores.

[0003] Currently, conventional wet leaching processes for processing low-grade manganese ore often face the following dilemma: If a single-stage leaching process is used, a high acidity is typically required to achieve a high leaching rate, but this results in a large amount of excess sulfuric acid remaining in the solution during the later stages of leaching. If this residual acid cannot be effectively utilized, direct neutralization requires a large amount of neutralizing agent (such as limestone, ammonia, etc.), which not only increases production costs but also introduces new impurity ions, affecting the purity of subsequent products.

[0004] While existing technologies include the concept of two-stage leaching, such as the existing technology "Leaching Method for Manganese Carbonate Ore Based on Two-Stage Leaching" (Publication No.: CN105296751A), their process layout and system integration do not focus on optimizing acid reuse. They fail to efficiently recover the residual acid after the second-stage leaching and reuse it in the first-stage leaching, leaving room for further improvement in economic and environmental benefits. Other processes, such as pressure leaching or roasting-leaching, can improve the leaching rate, but they suffer from problems such as large equipment investment, high energy consumption, and complex process flows, making large-scale promotion and application difficult.

[0005] Therefore, it is particularly important to develop a two-stage leaching system that can achieve internal acid circulation, reduce acid consumption and neutralization costs, improve leaching efficiency, and is easy to industrialize. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the existing technology and provide a two-stage leaching system with simple equipment, low acid consumption, and high leaching rate, which realizes internal circulation of acid and graded leaching, and is particularly suitable for the processing of low-grade manganese carbonate ore.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A two-stage leaching system, comprising a first-stage leaching tank, a thickener, a second-stage leaching tank, and a filter press connected in sequence; the outlet of the first-stage leaching tank is connected to the inlet of the thickener via a first pipe equipped with a pump; the overflow port of the thickener is connected to an overflow tank, and the outlet of the overflow tank is connected to a purification tank; the underflow outlet of the thickener is connected to the inlet of the second-stage leaching tank via a second pipe; the outlet of the second-stage leaching tank is connected to the inlet of the filter press via a third pipe; the filtrate outlet of the filter press is connected to the inlet of the first-stage leaching tank via a return pipe.

[0008] Furthermore, the pH value of the reaction in the leaching tank is 5.0-6.0, which is used for neutral leaching, consuming reflux acid and dissolving easily reactive minerals.

[0009] Furthermore, the sulfuric acid concentration in the two-stage leaching tank is 1-200 g / L, which is used for high acid leaching to dissolve sparingly soluble minerals.

[0010] Furthermore, the system is used to process manganese carbonate ore with a content of <30% or manganese monoxide ore with a Mn content of <50% through reduction roasting.

[0011] Furthermore, both the first-stage leaching tank and the second-stage leaching tank are equipped with stirring devices to ensure that the materials are fully mixed and reacted.

[0012] Furthermore, the thickener is a high-efficiency thickener, which improves the solid-liquid separation efficiency.

[0013] Furthermore, the filter press is a plate and frame filter press or a chamber filter press to ensure good filtration effect.

[0014] Furthermore, the return pipe is equipped with a flow control valve for adjusting the return liquid volume.

[0015] The working principle of this utility model is as follows: 1. First stage leaching: The mineral powder and the reflux acidic filtrate are leached in a first stage leaching tank under neutral conditions (pH=5.0-6.0) to initially dissolve easily reactive minerals such as manganese carbonate. The main reaction is: MnCO3 + H2SO4 → MnSO4 + CO2 + H2O; 2. Thickening and Separation: The slurry after the first stage of leaching is separated into solid and liquid by a thickener. The overflow (qualified manganese solution) is sent to a purification tank for further treatment, and the underflow (containing undissolved minerals) is pumped into the second stage leaching tank. 3. Second-stage leaching: Add sulfuric acid to the second-stage leaching tank for high-acid leaching (acid concentration 1-200g / L) to completely dissolve sparingly soluble minerals; 4. Filter press reflux: The two-stage slurry is separated by a filter press, the waste residue is discharged, and the acidic filtrate (containing residual H2SO4) is completely refluxed back to the first-stage leaching tank through the reflux pipe as bottom liquid for recycling.

[0016] The beneficial effects of this utility model are as follows: 1. High-efficiency acid recycling reduces costs: By recirculating the acidic filtrate after the second-stage high-acid leaching to the first-stage leaching tank, the residual sulfuric acid is recycled, significantly reducing the consumption of fresh sulfuric acid. At the same time, it greatly reduces the amount of neutralizing agent required to neutralize the residual acid, thereby reducing production costs and avoiding the problem of impurities introduced by neutralization.

[0017] 2. Improve leaching rate: A two-stage countercurrent leaching mode is adopted. The first stage of neutral leaching consumes the residual acid returned from the second stage, while the second stage of high-acid leaching specifically treats the insoluble parts. The two-stage enhancement ensures a high leaching rate for low-grade manganese ore, especially manganese carbonate ore.

[0018] 3. The system is simple and easy to industrialize: The system of this utility model is mainly composed of conventional leaching tanks, thickeners, filter presses and other equipment. It does not require harsh conditions such as high temperature and high pressure. The equipment investment is small, the operation is simple and the energy consumption is low, making it very suitable for large-scale industrial applications.

[0019] 4. Integrated optimization for improved efficiency: By rationally setting the location of the thickener and optimizing the design of the filtrate return path, efficient material separation and internal circulation of the medium are achieved, improving the overall system's operating efficiency and economy. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the system structure of this utility model; Figure 2 This is a schematic diagram of the front view of this utility model.

[0021] Markings in the figure 1. First leaching tank; 2. First pipeline; 3. Thickener; 4. Overflow tank; 5. Second pipeline; 6. Purification tank; 7. Second leaching tank; 8. Third pipeline; 9. Filter press; 10. Pump. Detailed Implementation

[0022] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0023] like Figure 1 and Figure 2As shown, the two-stage leaching system of this utility model includes a primary leaching tank 1, a thickener 3, a secondary leaching tank 7, and a filter press 9. The outlet of the primary leaching tank 1 is connected to the inlet of the thickener 3 via a first pipe 2 equipped with a pump 10. The overflow port of the thickener 3 is connected to an overflow tank 4, and the outlet of the overflow tank 4 is connected to the subsequent purification tank 6. The underflow outlet of the thickener 3 is connected to the inlet of the secondary leaching tank 7 via a second pipe 5. The outlet of the secondary leaching tank 7 is connected to the inlet of the filter press 9 via a third pipe 8. The filtrate outlet of the filter press 9 is connected back to the inlet of the primary leaching tank 1 via a return pipe.

[0024] Both the primary leaching tank 1 and the secondary leaching tank 7 are equipped with stirring devices to ensure thorough mixing and reaction of the slurry and acid. The thickener 3 is a high-efficiency thickener to improve solid-liquid separation efficiency. The filter press 9 is a plate and frame filter press to ensure good filtration effect. The reflux pipeline is equipped with a flow control valve for precise adjustment of the reflux liquid volume.

[0025] The following example illustrates the leaching of a low-grade manganese carbonate ore: Raw material: Manganese carbonate ore powder (Mn content 22.2%, CaO content 8.3%), with 95% particle size at -200 mesh. First stage leaching: 200 kg of ore powder and reflux acidic filtrate (containing 15 g / L H2SO4) react in the first stage leaching tank 1 for 2 hours, controlling the pH at 5.4. Thickening and separation: The resulting overflow liquid has an Mn²⁺ concentration of 18 g / L, and the underflow yield is approximately 45%. Second stage leaching: The underflow is pumped into the second stage leaching tank 7, and concentrated sulfuric acid is added until the system acid concentration reaches 150 g / L, reacting for 3 hours. Filter press reflux: After the second stage slurry is filtered by filter press 9, the filtrate (H2SO4 concentration approximately 18 g / L) is completely refluxed back to the first stage leaching tank 1. Results: The overall leaching rate of manganese reached 97.6%, the sulfuric acid consumption was reduced by 12% compared with the traditional single-stage leaching process, and no additional cost was required to neutralize the residual acid.

[0026] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any person skilled in the art can make many possible variations and modifications to the present utility model's technical solution, or modify it into equivalent embodiments, without departing from the scope of the present utility model's technical solution. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model, without departing from the content of the present utility model's technical solution, should still fall within the protection scope of the present utility model's technical solution.

Claims

1. A two-stage leaching system, characterized in that, The system includes a first leaching tank (1), a thickener (3), a second leaching tank (7), and a filter press (9) connected in sequence. The outlet of the first leaching tank (1) is connected to the inlet of the thickener (3) through a first pipe (2) with a pump (10). The overflow port of the thickener (3) is connected to an overflow tank (4). The underflow outlet of the thickener (3) is connected to the inlet of the second leaching tank (7) through a second pipe (5). The outlet of the second leaching tank (7) is connected to the inlet of the filter press (9) through a third pipe (8). The filtrate outlet of the filter press (9) is connected to the inlet of the first leaching tank (1) through a return pipe.

2. The two-stage leaching system according to claim 1, characterized in that: The pH value of the reaction in the leaching tank (1) is 5.0-6.

0.

3. The two-stage leaching system according to claim 1, characterized in that: The sulfuric acid concentration in the two-stage leaching tank (7) is 1-200 g / L.

4. The two-stage leaching system according to claim 1, characterized in that: The system is used to process manganese carbonate ore with a Mn content of <30% or manganese monoxide ore with a Mn content of <50% through reduction roasting.

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