Nickel pressure leaching flash tank nozzle

Abstract

The utility model discloses a kind of flash tank nozzles for nickel pressure leaching, its structure is in turn for: feed section, contraction section and diffusion section along ore pulp flow direction.The nozzle generates cyclone by spiral flow guide, contraction middle section wear layer resists violent scour, diffusion section flow guide prevents scale blockage, realizes that ore pulp is uniform, steady decompression.Its advantage is significantly improve wear resistance and service life, effectively reduce scale blockage, guarantee the stable operation of flash process, especially applicable to high temperature and high pressure ore pulp working condition of nickel pressure acid leaching.

Description

Technical Field

[0001] This utility model belongs to the field of hydrometallurgical technology, specifically relating to a flash tank nozzle for nickel pressure leaching. Background Technology

[0002] In the pressurized acid leaching process of nickel, the slurry after high-pressure, high-temperature leaching needs to be rapidly depressurized to near atmospheric pressure in a flash tank to achieve flash cooling and steam recovery. The flash tank nozzle, as a key component, directly affects the stability of the depressurization process, equipment lifespan, and system operating efficiency.

[0003] Currently, most flash tank nozzles adopt a simple cylindrical or conical structure. This type of structure has revealed the following problems in actual operation: First, it has poor wear resistance. The high-speed flow of solid mineral slurry causes severe erosion in the nozzle throat area, especially under high pressure differential conditions. Ordinary material nozzles are easily worn, resulting in a shortened service life and the need for frequent replacement, which increases maintenance costs and the risk of production interruption.

[0004] Secondly, scaling and clogging are prone to occur. During the depressurization process, solid particles are easily precipitated from the slurry or scale may adhere to the nozzle outlet and flash tank wall. After long-term operation, this may cause a reduction in the flow cross-section or even complete blockage, affecting production continuity and processing capacity.

[0005] Third, there is insufficient operational stability. The simple flow channel structure makes it difficult to achieve a smooth depressurization of the slurry, which can easily lead to cavitation and pipeline vibration, reducing equipment safety and potentially affecting flash evaporation and steam recovery efficiency.

[0006] Therefore, there is an urgent need for a flash tank nozzle with optimized structure, wear and corrosion resistance, that can effectively guide the smooth depressurization of the slurry and reduce scaling and clogging, to adapt to the high temperature, high pressure, and highly corrosive conditions of nickel pressure leaching processes. Utility Model Content

[0007] To address the problems of poor wear resistance, easy scaling and clogging, and unstable operation of existing flash tank nozzles, this invention provides a flash tank nozzle for nickel pressure leaching. Its purpose is to significantly improve the nozzle's wear resistance and corrosion resistance, effectively reduce scaling and clogging, and ensure uniform and stable pressure reduction of the slurry, thereby guaranteeing long-term stable operation of the flash leaching process and reducing maintenance costs.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: A flash tank nozzle for nickel pressure leaching includes a feed section, a contraction section, and a diffusion section coaxially connected in sequence along the slurry flow direction.

[0009] The feeding section is a cylindrical structure with several spiral guide lines on its inner wall to generate swirling flow in the slurry, thereby achieving preliminary mixing and flow optimization.

[0010] The contraction section is a conical contraction structure connected to the rear end of the feed section. Its inner wall surface is coated with a wear-resistant and corrosion-resistant layer to resist the severe scouring and chemical corrosion of high-speed slurry.

[0011] The diffusion section is a conical expansion structure connected to the rear end of the contraction section. Its function is to smoothly diffuse and decelerate the slurry accelerated by the contraction section and release it evenly into the flash tank to prevent local eddies and scaling.

[0012] Furthermore, the wear-resistant and corrosion-resistant layer is a tungsten carbide-based hard alloy layer, which has extremely high hardness and excellent corrosion resistance.

[0013] Furthermore, the number of spiral guide lines on the inner wall of the feed section is 6 to 10, preferably 8, to achieve the best balance between flow resistance and swirling effect.

[0014] Furthermore, the length of the contraction section is 1.0 to 2.5 times its inner diameter at the inlet, a range that ensures a stable flow transition and effective protection of the wear-resistant layer.

[0015] Furthermore, the cone angle of the diffusion section is 5° to 15°. This angle range can effectively prevent flow separation and ensure that the slurry can adhere to the wall surface and expand smoothly, thereby achieving efficient and stable energy conversion.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. Significantly improved wear resistance and service life: By compositing a tungsten carbide-based hard alloy wear-resistant layer on the inner wall of the contraction section, which is subjected to the most severe scouring, the wear resistance and corrosion resistance of the nozzle are greatly improved, enabling it to adapt to the harsh working conditions of nickel pressure leaching of high temperature and high pressure slurry, thus extending its service life many times over and significantly reducing the replacement frequency and maintenance costs.

[0017] 2. Effectively prevents scaling and clogging: The spiral guide pattern in the feed section causes the slurry to swirl, which initially improves its flow state; the conical expansion design in the diffusion section allows the slurry to decelerate and diffuse evenly when leaving the nozzle, avoiding local accumulation at the nozzle outlet and the flash tank wall, thus fundamentally reducing the risk of scaling and clogging from the flow design perspective.

[0018] 3. Stable operation and reliable safety: This utility model adopts a stepped flow channel design of "feeding (swirling) - contraction (acceleration) - diffusion (deceleration)", which, together with the rotational movement of the slurry, enables the pressure of the high-pressure slurry to be reduced steadily step by step. This effectively reduces the cavitation phenomenon and pipeline vibration that are prone to occur in traditional direct injection structures, and improves the stability and safety of the entire flash evaporation system.

[0019] 4. Simple structure and strong practicality: The structure of this utility model is reasonable, the functions of each component are clear, and it is easy to manufacture and install. It is very suitable for promotion and application in the nickel pressure leaching process in the field of hydrometallurgy. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of this utility model.

[0021] In the diagram: 1-feeding section, 2-shrinkage section, 3-diffusion section, 1-1-spiral guide pattern, 2-1-wear-resistant and corrosion-resistant layer. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the following embodiments are only for explaining the present invention and are not intended to limit the scope of protection of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] like Figure 1 As shown, the flash tank nozzle for nickel pressure leaching provided by this utility model is mainly composed of a feed section 1, a shrinkage section 2 and a diffusion section 3 connected coaxially in sequence.

[0024] The feed section 1 is a cylindrical pipe section made of corrosion-resistant metal material (such as duplex stainless steel). Eight evenly distributed spiral guide lines 1-1 are machined on its inner wall. The depth and pitch of these spiral lines can be optimized according to the flow rate and characteristics of the slurry. Their core function is to guide the high-pressure slurry, causing it to generate a strong rotating flow (vortex), laying the foundation for a smooth flow field for subsequent pressure reduction.

[0025] The contraction section 2 is welded or connected to the rear end of the feed section 1 via a flange. Its flow channel cross-section is conical, gradually narrowing along the slurry flow direction. This section is the most severely affected by slurry erosion and corrosion. Therefore, a wear-resistant and corrosion-resistant layer 2-1 is laminated onto its inner wall surface using thermal spraying, welding, or inlay processes. In this embodiment, the wear-resistant and corrosion-resistant layer 2-1 is preferably a tungsten carbide-based (WC) hard alloy layer, the thickness of which can be designed according to wear expectations, typically 2-3 mm. This layer has extremely high hardness (HRA≥88) and good acid corrosion resistance, effectively resisting the erosion of high-speed solids-containing slurry. The length (L) of the contraction section 2 is designed to be 1.0 to 2.5 times its inlet inner diameter (D) (i.e., L / D=1.0~2.5). This aspect ratio range ensures a smooth and gradual transition and acceleration of the flow field, avoiding turbulence or eddies, while providing sufficient protective area for the wear-resistant layer.

[0026] The diffuser section 3 is welded or connected to the rear end of the contraction section 2 via a flange. Its flow channel cross-section is conical, gradually expanding along the slurry flow direction. The cone angle (α) of this section is designed to be between 5° and 15°. This angle range is optimized to ensure that the slurry flow accelerated by the contraction section diffuses smoothly and closely against the wall, achieving uniform pressure release and a smooth reduction in flow velocity. This effectively avoids local eddies, cavitation, and scaling and clogging in the outlet area caused by flow separation.

[0027] Working Principle: The high-pressure slurry first enters the feed section 1, where it forms a swirling flow under the action of the spiral guide pattern 1-1. This swirling flow not only ensures initial homogenization of the slurry components but also helps stabilize the subsequent flow field due to its rotational kinetic energy. Subsequently, the slurry enters the intermediate contraction section 2, where the cross-sectional area of ​​the flow channel decreases, the flow velocity increases, and the pressure decreases. Because the inner wall of this section is coated with an ultra-hard tungsten carbide layer, wear is minimized despite the extremely high flow velocity and intense scouring. Finally, the slurry enters the discharge expansion section 3, where the cross-sectional area of ​​the flow channel increases, the flow velocity decreases steadily, and the pressure is further reduced to near atmospheric pressure. Ultimately, it is injected into the flash tank in a uniform and diffused state, completing the flash evaporation process. The entire process achieves efficient, stable, and long-life operation through the multi-stage synergistic effect of "swirling pre-stabilization → wear-resistant accelerated contraction → stable diffusion pressure reduction".

[0028] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the technical scope disclosed in this utility model, based on the technical solution and inventive concept of this utility model, should be included within the protection scope of this utility model.

Claims

1. A flash tank nozzle for pressure leaching of nickel, comprising a feed section, a contraction section, and a diffusion section coaxially connected in sequence along the slurry flow direction; characterized in that: The feeding section has a cylindrical structure with several spiral guide lines on its inner wall; The inner wall of the contraction section is coated with a wear-resistant and corrosion-resistant layer. The diffusion section has a conical expansion structure.

2. The flash tank nozzle according to claim 1, characterized in that: The wear-resistant and corrosion-resistant layer is a tungsten carbide-based hard alloy layer.

3. The flash tank nozzle according to claim 1, characterized in that: The number of spiral guide lines on the inner wall of the feeding section is 6 to 10.

4. The flash tank nozzle according to claim 1, characterized in that: The length of the contracted section is 1.0 to 2.5 times its inner diameter.

5. The flash tank nozzle according to claim 1, characterized in that: The cone angle of the diffusion section is 5° to 15°.

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