A sand screening and washing device and method

Abstract

The application discloses a sand screening and washing device and belongs to the technical field of screening and washing equipment. The device can effectively prolong the residence time of slurry on the screen surface, promote the fine particle qualified material to fully pass through the screen, thereby improving the under-screen yield, reducing the circulating load on the screen and reducing the water consumption in production. The sand screening and washing device comprises a first plate, a second plate body and a flushing assembly. The first plate body is a non-porous plate, and the discharge end is provided with a first material retaining dam. The second plate body is a porous screen plate and is used for vibrating screening. The second plate body is adjacent to the discharge end of the first plate body. The flushing assembly is arranged above the first plate body and is used for providing flushing liquid to the surface of the first plate body. The flushing assembly flushes the surface of the first plate body, and the material is gathered at the first material retaining dam. When the gathered material flows over the first material retaining dam, the material flows to the second plate body.

Description

Technical Field

[0001] This application belongs to the technical field of screening and washing equipment, and particularly relates to a sand screening and washing device and a sand screening and washing method. Background Technology

[0002] In the closed-circuit screening process of wet sand making using a rod mill, a linear screen is typically used, supplemented by on-screen washing water to improve screening efficiency. However, after the rod mill discharge slurry is fed into the screen surface, the water in the slurry quickly escapes through the screen openings, making it difficult for the screen surface to maintain the slurry state. At this time, the additional washing water also quickly passes through the screen openings, failing to form an effective slurry carrying fine particles on the screen surface. As a result, the undersize output is not significantly improved, and a large amount of qualified fine particles remain on the screen, causing an increase in on-screen circulation. This not only increases the burden on the rod mill and the risk of over-grinding but also leads to a significant increase in process water consumption. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a sand washing device and method that can effectively prolong the residence time of the slurry on the screen surface, promote the full passage of fine-grained qualified materials through the screen, thereby increasing the output of undersize material, reducing the circulating load on the screen, and reducing production water consumption.

[0004] The first aspect of this application provides a sand screening and washing device, including: a first plate body, which is a non-perforated plate, and a first baffle dam is provided at the discharge end of the first plate body; The second plate is a perforated sieve plate used for vibrating screening; the discharge end of the second plate is adjacent to the discharge end of the first plate. A rinsing assembly, disposed above the first plate, is used to provide rinsing fluid to the surface of the first plate. The flushing component flushes the surface of the first plate, causing the material to accumulate at the first retaining dam. When the accumulated material overflows the first retaining dam, the material flows toward the second plate. In some implementations, the height of the first retaining dam is adjustable.

[0005] In some embodiments, the first retaining dam is detachably connected to the first plate.

[0006] In some embodiments, the first plate is provided with a guide groove extending along the material flow direction.

[0007] In some embodiments, the bottom of the guide channel is an inclined surface, and the inclined surface gradually rises from the end away from the second plate to the end closer to the second plate.

[0008] In some embodiments, there are multiple guide channels, which are parallel to each other and spaced apart along the width direction of the first plate.

[0009] In some embodiments, a second retaining dam is provided between adjacent guide channels.

[0010] In some embodiments, the top of the second retaining dam is lower than the top of the first retaining dam.

[0011] In some embodiments, the first plate and the second plate are fixedly connected so that the first plate vibrates synchronously with the second plate.

[0012] A first aspect of this application provides a method for screening and washing sand, applied to the sand screening and washing apparatus described in the first aspect embodiment, the sand screening and washing method comprising: Feed the material into the first plate; The flushing assembly is controlled to provide flushing fluid to the surface of the first plate, causing the material to accumulate at the first material dam of the first plate. When the aggregated material overflows the first retaining dam, the material flows toward the second plate. Controlling the vibration of the second plate to screen the material. The sand washing device of this application sets the first plate as a non-perforated plate and sets a first baffle at its discharge end. This prevents the washing liquid provided by the washing components from flowing away immediately, allowing it to accumulate on the surface of the non-perforated plate to form a stable slurry zone. When the rod mill discharges slurry into this zone, the material is fully soaked and dispersed in the washing liquid, extending the effective washing time. At the same time, the first baffle promotes the continuous accumulation of material, forming a submerged conveying state, thereby solving the problem of rapid water loss and inability to maintain the slurry shape on linear screens in related technologies. As the material accumulates and overflows the first baffle, the slurry enters the adjacent second plate (perforated screen plate) in a continuous, gentle, and full-flow manner. At this time, because the material has already formed a high-concentration slurry, its ability to carry fine particles is much higher than that of direct water washing. Therefore, during the vibrating screening process, a large number of qualified fine particles can pass smoothly through the screen holes with the slurry, significantly increasing the output of the undersize material. Meanwhile, the proportion of coarse particles in the oversize material increases and the entrainment of fine particles decreases, thereby reducing the circulating load to the rod mill and avoiding the risk of over-grinding. At the same time, since the rinsing fluid is first effectively utilized by the material on the non-porous plate, rather than being directly lost, the overall water consumption is significantly reduced. Attached Figure Description

[0013] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which: Figure 1 This is a schematic application scenario diagram of a sand screening and washing device provided in one or more embodiments of this application. Figure 2 This is a schematic cross-sectional view of the first plate body provided in one or more embodiments of this application; Figure 3This is a schematic top view of the first plate body provided in one or more embodiments of this application; Figure 4 This is a schematic flowchart of a sand screening and washing method provided in one or more embodiments of this application. Detailed Implementation

[0014] To better understand the technical solutions provided in the embodiments of this specification, the technical solutions of the embodiments of this specification will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of this specification and the specific features in the embodiments are detailed descriptions of the technical solutions of the embodiments of this specification, rather than limitations on the technical solutions of this specification. In the absence of conflict, the embodiments of this specification and the technical features in the embodiments can be combined with each other.

[0015] In this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, without necessarily requiring or implying any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, the requirement defined by the phrase "comprising one..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element. The term "two or more" includes two or more cases.

[0016] In the closed-circuit screening process of wet sand making using a rod mill, a linear screen is typically used, supplemented by on-screen washing water to improve screening efficiency. However, after the rod mill discharge slurry is fed into the screen surface, the water in the slurry quickly escapes through the screen openings, making it difficult for the screen surface to maintain the slurry state. At this time, the additional washing water also quickly passes through the screen openings, failing to form an effective slurry carrying fine particles on the screen surface. As a result, the undersize output is not significantly improved, and a large amount of qualified fine particles remain on the screen, causing an increase in on-screen circulation. This not only increases the burden on the rod mill and the risk of over-grinding but also leads to a significant increase in process water consumption.

[0017] In view of this, the present application provides a sand washing device and a sand washing method, which can effectively prolong the residence time of the slurry on the screen surface, promote the full passage of fine-grained qualified materials through the screen, thereby increasing the output under the screen, reducing the circulating load on the screen and reducing production water consumption.

[0018] The first aspect of this application provides a sand screening and washing device. For example... Figures 1 to 3As shown, the sand washing device includes a first plate 100, a second plate 200, and a washing assembly 300. The first plate 100 is a non-porous flat plate, which can be made of wear-resistant steel plate or high-polymer wear-resistant sheet material. A first baffle 110 is fixedly installed at its discharge end. The height of the first baffle 110 can be set according to the actual material flow rate and the required slurry depth.

[0019] The second plate 200 is a perforated screen plate, the aperture of which can be determined according to the requirements of the screening process. The second plate 200 is adjacent to the discharge end of the first plate 100, and a vibrating exciter (not shown in the figure) is provided below the second plate 200, enabling it to perform linear or circular vibration in the working state. The rinsing assembly 300 is installed directly above the first plate 100, including at least one rinsing water pipe 310, on which multiple water spray holes or nozzles are evenly opened, and the water spray direction is towards the upper surface of the first plate 100.

[0020] During closed-circuit screening for wet sand making in a rod mill, the slurry discharged from the rod mill is continuously conveyed to the feed end of the first plate 100 through the feed pipe. The flushing assembly 300 is activated, and the flushing liquid (usually water) is sprayed onto the surface of the first plate 100 at a certain pressure. Because the first plate 100 is a non-perforated plate, the flushing liquid does not leak immediately, but forms a water film on the surface of the first plate 100 and gradually accumulates. Simultaneously, the incoming slurry mixes with the water... Figure 1 In this mixture (where M represents the slurry and water), the material and liquid continuously accumulate in front of the first retaining dam 110, forming a slurry zone of a certain depth (e.g., just submerging half to all of the height of the first retaining dam 110). Within this zone, the material is fully soaked and dispersed; fine particles detach from the surface of coarse particles and remain suspended in the slurry, while coarse particles slowly move forward within the slurry. As feeding continues, the accumulated material level rises continuously. When the material mixture overflows the top of the first retaining dam 110, it flows towards the adjacent second plate 200 in a gentle, uniform laminar flow state.

[0021] The second plate 200 screens the incoming slurry under vibration. Since the slurry already contains a large amount of suspended fine particles, when the slurry is evenly distributed on the screen surface, the fine particles quickly pass through the screen holes and fall into the undersize collection hopper, becoming qualified products. Coarse particles, however, are blocked by the screen surface and move forward under vibration, exiting from the discharge end of the second plate 200 and returning to the rod mill for re-grinding as oversize material. During this process, because the slurry has already formed a stable, high-concentration suspension before entering the screen, the phenomenon of direct spraying of washing water onto the dry screen surface and rapid water loss, as seen in traditional processes, is avoided. This significantly improves the screening rate of fine particles, reduces the circulating load on the screen, and also reduces the total water consumption.

[0022] In some embodiments, the height of the first baffle 110 is adjustable. For example, the first baffle 110 can adopt a telescopic structure, including a fixed part and a lifting part. The fixed part is installed at the discharge end of the first plate 100, and the lifting part moves up and down relative to the fixed part by a drive mechanism such as bolts, sliders, or hydraulic cylinders, and is maintained at a set height by a locking device. Another approach is to use multiple baffles of different heights for replacement, achieving height adjustment through quick replacement. In actual production, based on the flow rate, concentration, and target slurry depth of the rod mill discharge, the operator can easily adjust the height of the first baffle 110 (e.g., stepless or stepped adjustment within the range of 20–100 mm) to control the aggregation and residence time of the material on the first plate 100. When it is necessary to improve the washing effect and extend the soaking time, the baffle height is increased; when it is necessary to increase the throughput and accelerate material conveying, the baffle height is decreased. This adjustable design significantly improves the adaptability of the device to different material characteristics and process requirements.

[0023] In some embodiments, the first retaining dam 110 is detachably connected to the first plate 100. For example, the discharge end of the first plate 100 is provided with a dovetail groove or a T-groove, and the bottom of the first retaining dam 110 is provided with a convex rail that mates with it. The retaining dam slides in from the side and is fixed by an end limiting block or screws. Alternatively, a bolted connection can be used: the bottom of the first retaining dam 110 is provided with a connecting plate, and the corresponding position of the first plate 100 has threaded holes. Multiple bolts are used for fastening, and replacement can be done simply by unscrewing the bolts. The detachable connection not only facilitates the replacement of retaining dams of different heights, but also facilitates the cleaning, maintenance, or material replacement of the retaining dam (e.g., replacing with wear-resistant materials after wear). Furthermore, when the first plate 100 needs thorough cleaning, removing the retaining dam allows for unobstructed cleaning of the dead corners behind it. This structure is simple, low-cost, and beneficial for equipment maintenance and long-term operation.

[0024] In some embodiments, such as Figures 1 to 3 As shown, to address the issues of uneven material flow, localized accumulation, or flow deviation on the non-porous first plate 100, this design incorporates a guide channel 120 extending along the material flow direction on the first plate 100. The guide channel 120 can be a stamped groove, or a V-shaped, U-shaped, or rectangular channel formed by welding or milling. The guide channel 120 extends from the feed end of the first plate 100 to near the discharge end (ending before or intersecting with the first retaining dam 110). When the rod mill discharge slurry and flushing liquid enter the first plate 100, the guide channel 120 guides the material forward in an orderly manner along the channel, preventing disorderly diffusion to both sides, thus forming a more uniform slurry distribution in front of the dam. This facilitates full contact between the material and the flushing liquid and prevents localized drying or fine particle deposition. Furthermore, the guide channel 120 increases the relative movement between solid particles and the plate surface, promoting the peeling off of fine particles adhering to the surface of coarse particles.

[0025] In some embodiments, such as Figure 2 As shown, based on the existing guide channel 120, the bottom of the guide channel 120 can be further defined as an inclined surface, and the inclined surface gradually rises from the end away from the second plate 200 to the end closer to the second plate 200. That is, the bottom of the guide channel 120 is lower at the feed end (the end away from the second plate 200) and higher at the discharge end (the end closer to the second plate 200), forming a reverse slope (the slope can be 2°). The two side walls of the guide channel 120 can also be inclined at an angle, for example, 30° relative to the axis of the guide channel 120. This inclined slope is more conducive to the flow of the slurry towards the discharge end.

[0026] This seemingly unconventional design actually has a unique effect: as the material flows along the guide channel 120 towards the first retaining dam 110 under the propulsion of the flushing fluid, the bottom of the channel gradually rises, creating a slight climbing effect. This forces the material flow rate to slow down and causes coarse particles to stagnate or tumble during the climbing process, while fine particles and water are more easily suspended in the upper layer. At the same time, the reverse slope helps to enhance the underwater stirring effect, allowing the fine mud adhering to the surface of the coarse particles to be more fully removed. When the material overflows the first retaining dam 110, due to the inclination of the channel bottom, the slurry depth in the area in front of the dam is more consistent along the width direction, avoiding the phenomenon of fast flow velocity in the middle and slow flow velocity on both sides, thus ensuring the uniformity of the slurry entering the second plate 200.

[0027] In some embodiments, such as Figure 2 and Figure 3 As shown, multiple guide channels 120 can be configured, with the multiple guide channels 120 arranged parallel to each other and spaced apart along the width direction of the first plate 100. For example, if the width of the first plate 100 is 1.5 meters, 5 to 8 guide channels 120 can be provided, each channel being 30 to 50 mm wide, 20 to 30 mm deep, and spaced 80 to 120 mm apart. The multiple parallel guide channels 120 divide the first plate 100 into several parallel material flow channels. The slurry discharged from the rod mill is evenly distributed into each guide channel 120 through a distributor at the feed end. The material in each channel moves forward independently, forming several parallel small slurry pools in front of the first retaining dam 110. This multi-channel structure can eliminate the problems of material deviation, accumulation, or short-circuiting on a single large-area plate, ensuring that the material in each local area can be fully washed, and that when the material in one channel overflows the retaining dam first, it will not affect the residence time of other channels. Ultimately, the material enters the second plate 200 simultaneously in multiple parallel flows, and after being superimposed, it forms a uniform full-width feed, which greatly improves the efficiency of subsequent screening.

[0028] In some embodiments, based on the provision of multiple parallel guide channels 120, in order to prevent material from flowing between adjacent guide channels 120 or from lateral migration, a second baffle (not shown in the figure) is provided between adjacent guide channels 120. The second baffle is an elongated protrusion extending along the material flow direction, which can be welded or bolted to the first plate 100. Its height is generally lower than the first baffle 110 but higher than the bottom of the guide channel 120.

[0029] The function of the second baffle is twofold: firstly, it completely separates each guide channel 120 into an independent conveying channel, ensuring that material in each channel does not cross the baffle and enter adjacent channels, thus maintaining the stability of the feed between channels; secondly, the second baffle itself also serves as an auxiliary material retainer, increasing the plate's ability to hold the slurry, and its top can serve as a reference for secondary overflow. When the flushing water volume temporarily increases or the flow rate fluctuates, the second baffle can prevent a large amount of material from overflowing from one channel and affecting the concentration balance of adjacent channels, ensuring the consistency of the process between each flow channel.

[0030] In some embodiments, to further optimize the material overflow sequence and slurry depth distribution, the top of the second retaining dam is lower than the top of the first retaining dam 110. In actual operation, the first retaining dam 110 is the final overflow dam, controlling the maximum liquid holding depth of the entire first plate 100; while the second retaining dam serves as an intermediate dividing dam, with its top lower than the first retaining dam 110.

[0031] In this way, when the slurry level in each guide channel 120 rises, it will preferentially overflow the lower second baffle. However, there is a height difference between the top of the second baffle and the adjacent channel. The slurry that overflows the second baffle does not flow directly out of the first plate 100, but flows into the adjacent guide channel 120, thus forming a micro-circulation or cross-channel replenishment in each guide channel 120. This helps to balance the liquid level and concentration between channels and avoid local drying due to uneven feeding in individual channels. Only when the liquid level in all channels continues to rise to the height of the top of the first baffle 110 will the material overflow the first baffle 110 and enter the second plate 200. This mechanism of graded overflow and cross-channel homogenization makes the material more thoroughly mixed on the first plate 100 and the residence time distribution narrower, ensuring the stability of the screening feed.

[0032] In some embodiments, to simplify the equipment structure and reduce manufacturing costs, the first plate 100 and the second plate 200 are fixedly connected so that the first plate 100 vibrates synchronously with the second plate 200. For example, the first plate 100 and the second plate 200 are rigidly connected by welding or bolts to form an integral base plate assembly, which is mounted on the screen frame of the vibrating screen and shares the same set of vibrating exciter. When the exciter is working, the first plate 100 and the second plate 200 vibrate linearly or circularly together.

[0033] In this way, there is no need to set up a separate drive device or conveying mechanism for the first plate 100. The vibration of the screening machine can drive the material on the first plate 100 forward. At the same time, the vibration can promote the separation of coarse and fine particles, enhance the dispersion effect of the washing liquid, and prevent the material from sticking or accumulating on the first plate 100. Compared with the solution where the first plate 100 is stationary, the vibrating structure not only saves space and energy consumption, but also avoids the formation of dead zones in the material on the plate, making it particularly suitable for handling high-concentration, high-viscosity rod mill slurry.

[0034] like Figure 4 As shown, a second aspect of this application provides a sand washing method applied to the sand washing apparatus described in the first aspect embodiment, comprising the following steps: Step S101: Feed the material into the first plate 100. The slurry (or other sand and gravel materials to be screened and washed) discharged from the rod mill is continuously conveyed to the feed end of the first plate 100 through a feed pipe, feed box, or chute. The feeding speed can be adjusted according to process requirements, preferably so that the thickness of the material layer on the surface of the first plate 100 does not exceed 1.5 times the height of the first retaining dam 110.

[0035] Step S102: Control the flushing assembly 300 to provide flushing fluid to the surface of the first plate 100, causing the material to accumulate at the first retaining dam 110 of the first plate 100. Turn on the flushing assembly 300, and the flushing fluid (such as water or circulating water) is sprayed onto the surface of the first plate 100 at a certain pressure. Since the first plate 100 is a non-porous plate, the flushing fluid will not leak. After mixing with the fed material, it forms a slurry and gradually accumulates under the obstruction of the first retaining dam 110. Control the flushing fluid flow rate to match the feed rate (e.g., liquid-to-solid volume ratio 0.5:1 to 2:1) so that the material maintains a slurry layer of a certain depth in front of the first retaining dam 110 and remains there for a sufficient time to allow fine particles to disperse fully and coarse particles to be thoroughly washed. The height of the first retaining dam 110 can be adjusted as needed to change the slurry depth and residence time.

[0036] Step S103: When the aggregated material overflows the first retaining dam 110, the material flows towards the second plate 200. As the material is continuously fed in, the slurry level rises above the top of the first retaining dam 110, and the material flows over the retaining dam in a gentle, diffuse manner, flowing evenly towards the second plate 200 along the adjacent area between the first plate 100 and the second plate 200. The diffuse flow process should be as stable and continuous as possible, avoiding pulse-like scouring. If the first plate 100 is provided with a guide channel 120 and / or a second retaining dam, the material will diffuse along each guide channel 120 separately, further improving the uniformity of feeding.

[0037] Step S104: Control the vibration of the second plate 200 to screen the material. Start the vibratory exciter connected to the second plate 200 to cause linear or circular vibration (amplitude 2-8 mm, frequency 800-1500 rpm). The slurry flowing into the second plate 200 spreads rapidly under vibration. Fine particles pass through the screen holes with the liquid, becoming the undersize product, while coarse particles move forward on the screen surface and are discharged from the outlet of the second plate 200, returning to the rod mill for further grinding or used as finished coarse sand. No additional screen washing water is needed during vibration (or only a small amount of auxiliary washing is required), as the material enters the screen in slurry form, already possessing sufficient fine-carrying capacity.

[0038] The above method may further include the following preferred control strategy: Based on the undersize yield and oversize particle size distribution, the flow rate of the flushing component and / or the height of the first baffle 110 are adjusted to optimize the slurry concentration and residence time; when the first plate 100 vibrates synchronously with the second plate 200, the aggregation and forward movement of the material on the first plate 100 in step S102 are assisted by vibration. At this time, the height of the first baffle 110 can be appropriately reduced to utilize vibration energy to promote material flow. The method of this application effectively solves the technical problem in the wet sand making and screening process of rod mills in related technologies where water rapidly passes through the screen holes and cannot form an effective slurry, achieving closed-circuit screening with low water consumption and high undersize yield.

[0039] It should be noted that the descriptions of each embodiment in the above embodiments have different focuses. For parts that are not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0040] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

[0041] Although preferred embodiments have been described in this specification, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this specification.

[0042] Obviously, those skilled in the art can make various modifications and variations to this specification without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims and their equivalents, this specification is also intended to include such modifications and variations.

Claims

1. A sand washing and screening device, characterized in that, include: The first plate is a non-perforated plate, and the discharge end of the first plate is provided with a first material-blocking dam. The second plate is a perforated sieve plate used for vibrating screening; the discharge end of the second plate is adjacent to the discharge end of the first plate. A rinsing assembly, disposed above the first plate, is used to provide rinsing fluid to the surface of the first plate. The flushing component flushes the surface of the first plate, causing the material to accumulate at the first retaining dam. When the accumulated material overflows the first retaining dam, the material flows toward the second plate.

2. The sand washing device according to claim 1, characterized in that, The height of the first retaining dam is adjustable.

3. The sand washing device according to claim 2, characterized in that, The first material retaining dam is detachably connected to the first plate.

4. The sand washing device according to claim 1, characterized in that, The first plate is provided with a guide groove extending along the material flow direction.

5. The sand washing device according to claim 4, characterized in that, The bottom of the guide channel is an inclined surface, and the inclined surface gradually rises from the end away from the second plate to the end closer to the second plate.

6. The sand washing device according to claim 4 or 5, characterized in that, There are multiple guide channels, which are parallel to each other and spaced apart along the width direction of the first plate.

7. The sand washing device according to claim 6, characterized in that, A second retaining dam is provided between adjacent flow channels.

8. The sand washing device according to claim 7, characterized in that, The top of the second retaining dam is lower than the top of the first retaining dam.

9. The sand washing apparatus according to any one of claims 1 to 5, characterized in that, The first plate and the second plate are fixedly connected so that the first plate vibrates synchronously with the second plate.

10. A method for screening and washing sand, characterized in that, The sand washing apparatus according to any one of claims 1 to 9, wherein the sand washing method comprises: Feed the material into the first plate; The flushing assembly is controlled to provide flushing fluid to the surface of the first plate, causing the material to accumulate at the first material dam of the first plate. When the aggregated material overflows the first retaining dam, the material flows toward the second plate. The vibration of the second plate is controlled to screen the material.

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