CN218501325U

CN218501325U - Step tunnel type extraction tank

Info

Publication number: CN218501325U
Application number: CN202222735836.9U
Authority: CN
Inventors: 尹越峰
Original assignee: Myande Group Co Ltd
Current assignee: Myande Group Co Ltd
Priority date: 2022-10-17
Filing date: 2022-10-17
Publication date: 2023-02-21
Anticipated expiration: 2032-10-17

Abstract

The utility model discloses a step tunnel type extraction tank, including sealed box, the rear end of box is the feed end, the front end is equipped with the discharge gate, the inner chamber of box is equipped with multistage soaking unit from the front to the back, first stage soaking unit is close to the discharge gate, each stage soaking unit includes steeping cell and baffling board respectively, the steeping cell includes wallboard, arc bottom and inclined bottom plate that link gradually as an organic whole, the arc bottom holds this level lower shaft, the upper end of inclined bottom plate extends to the rear side of this level upper shaft, the upper end of wallboard is connected below the inclined bottom plate of back stage soaking cell; the upper parts of all levels of inclined bottom plates except the first level are respectively provided with a filtering grid plate, and the heights of the lower edges of the filtering grid plates are gradually reduced from front to back and are all higher than the top of the wallboard; the baffle plate is a solid plate parallel to each level of inclined bottom plate, the upper end of the baffle plate is higher than the liquid level, and the lower end of the baffle plate extends into the lower part of the soaking pool. In the step tunnel type extraction tank, solid materials are in full-countercurrent long-flow contact with extraction liquid, mass transfer is enhanced, a solvent cannot be short-circuited, and extraction efficiency is high.

Description

Step tunnel type extraction tank

Technical Field

The utility model relates to a leach the ware, especially relate to a step tunnel type extraction tank, belong to extraction equipment technical field.

Background

Extraction equipment is often used for extracting oil or other effective components, and the extraction equipment on the market is various and comprises a fixed bed type, a moving bed type, a basket type and a filter drum type. The general principle is that the solid is naturally piled up to form a stable material bed or is forced to form a stable material bed, the extract liquor or the washing liquor is poured from the upper part of the material bed, and the liquid permeates the material layer to complete the mass transfer process.

The Chinese patent with the publication number of CN 104474735B discloses a continuous extraction device and a process. The device comprises an extraction tank with a sealed main body, a plurality of groups of inclined scraper devices arranged in the extraction tank, an extraction material inlet and a solvent inlet arranged at different positions of the upper part of the extraction tank, and an extraction liquid outlet and an extraction material outlet arranged at two ends of the extraction tank respectively.

The extraction device has the following problems: 1. most of the solid materials are contacted with the extraction liquid in a laminar flow manner, so that the solid materials and the extraction liquid are not fully mixed;

2. the extract liquid flows automatically through the fall, the light phase is positioned at the upper part of the liquid layer, and the new solution is easy to generate short circuit;

3. the solid materials are not obviously drained, and more concentrated extraction solution is mixed in the materials pushed and climbed by the scraper, so that the concentration of the solvent on the low-concentration side is increased, the extraction power is reduced, and the extraction efficiency is reduced;

4. the extraction path appears to be longer, but the upper screen surface utilization of each set of leaching units is low.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to overcome the problem that exists among the prior art, provide a step tunnel type extraction tank, solid material can realize the long flow contact of full adverse current with the extract, strengthens the mass transfer process, and the solvent can not take place the short circuit, and the extraction is efficient.

For solving above technical problem, the utility model discloses a step tunnel type extraction tank, including sealed box, the rear end of box is the feed end, and the front end is equipped with the discharge gate, and the box inner chamber is equipped with multistage soaking unit backward in the past, and first order soaking unit is close to the discharge gate, and soaking unit at different levels includes respectively:

a soaking pool: the device comprises a wall plate, an arc bottom and an inclined bottom plate which are sequentially connected into a whole, wherein the arc bottom accommodates a lower shaft of the stage, the upper end of the inclined bottom plate extends towards the rear side of an upper shaft of the stage, and the upper end of the wall plate is connected below the inclined bottom plate of a soaking pool of the next stage; the upper parts of all levels of inclined bottom plates except the first level are respectively provided with a filtering grid plate, and the heights of the lower edges of the filtering grid plates are gradually reduced from front to back and are all higher than the tops of the wall plates;

baffle plate: the upper end of the solid plate is higher than the liquid level, and the lower end of the solid plate is inserted into the lower part of the soaking pool.

As an improvement of the utility model, the baffle plate of the current stage extends from the front side of the upper shaft of the next stage to the top of the lower shaft of the current stage.

As a further improvement, the lower end faces of the baffle plates at all levels and the rear one-level inclined bottom plate form a downward tunnel of the material, and the upper end faces of the baffle plates at all levels and the front one-level inclined bottom plate form an upward tunnel of the material.

As a further improvement of the utility model, the plane of the lower shaft axis and the upper shaft axis of the current stage is intersected with the inclined bottom plate and the baffle plate of the current stage at acute angles.

As a further improvement of the utility model, the upper end of the inclined bottom plate is higher than the horizontal plane where the axis of the upper shaft is located, and the upper end of the baffle plate is close to the horizontal plane where the axis of the upper shaft is located.

As a further improvement of the utility model, a new solution spraying pipe is arranged at the upper part of the front side of the box body and is sprayed at the middle section of the inclined bottom plate of the first-stage soaking pool; the liquid level of the previous stage soaking pool is higher than that of the next stage soaking pool, a thick dissolving-out opening is formed in the rear wall of the last stage soaking pool, a baffle plate stretching into the liquid level is arranged on the front side of the thick dissolving-out opening, and a thick mixing settling zone is formed between the baffle plate and the rear wall of the last stage soaking pool.

As a further improvement of the utility model, the side wall of the first-stage soaking pool is provided with a box overflow port for controlling the highest liquid level.

As a further improvement of the utility model, a solid material feed inlet is arranged at the rear part of the top wall of the box body and is positioned above the final-stage baffle plate; the feeding device is characterized in that a semi-fluid material feeding hole is formed in the front of the solid material feeding hole, a feeding platform is arranged below the semi-fluid material feeding hole, and the feeding platform is located above the last-stage upper shaft.

As a further improvement of the utility model, a feeding adjusting gate is arranged at the rear upper part of the final stage baffle plate.

Compared with the prior art, the utility model discloses following beneficial effect has been obtained: 1. the solvent and wet meal always ensure countercurrent soaking contact in a tunnel formed by an inclined bottom plate and a baffle plate, a forced mass transfer process is carried out, and high extraction power is always kept;

2. after the new solution enters the first-stage soaking pool, the new solution automatically overflows backwards step by utilizing the liquid level difference and fully contacts with the materials to transfer mass through the baffling of the baffle plate, so that the short circuit phenomenon of flowing along the surface can not occur;

3. the materials are subjected to the steps of soaking, solid-liquid mixing, fishing out, washing, draining and the like in each extraction unit, the solid materials finally enter a first-stage soaking pool, are fully mixed with a fresh solvent, are fished out by a scraper and drained, and are discharged out of the machine.

4. The solid material is added with a draining procedure in each stage of extraction process, a baffling channel is added in each stage of extraction liquid, the flow of liquid is more orderly and reasonable, the extraction principle is fully conformed, the extraction efficiency can be improved by more than 20 percent, and the preferential extraction process aiming at powdery or semi-fluid solid materials can be formed.

Drawings

The invention will be described in further detail with reference to the drawings and the detailed description, which are provided for reference and illustration purposes only and are not intended to limit the invention.

FIG. 1 is a schematic structural view of the step tunnel type extraction tank of the present invention;

FIG. 2 is a sectional view and a step level diagram of the present invention;

FIG. 3 is a perspective view of the step tunnel type extraction tank of the present invention;

FIG. 4 is a three-dimensional enlarged view of a certain soaking pool in the present invention;

in the figure: 1. a box body; 1a, a solid material feeding hole; 1b, a semi-fluid material feeding hole; 1c, a feeding platform; 1d, discharging a material outlet; 1e, an overflow port of the box body; 1f, a free gas interface; 1g, an access door; 1h, horizontally supporting the rail; 1j, a guide slide rail at the feeding side; 1k, a discharge side guide slide rail; 2. a feed adjusting gate; 3. a soaking pool; 3a, wallboard; 3b, arc bottom; 3c, a sloping bottom plate; 3d, filtering a grid plate; 3e, a concentrated solution outlet; 4. a baffle plate; 5. a striker plate; 6. a concentrated mixing and settling zone; 7. a lower shaft; 7a, a lower shaft conveying chain wheel; 8. an upper shaft; 8a, an upper shaft conveying chain wheel; 9. a conveying chain; 10. emptying the pipe; 11. a new solution spray pipe.

Detailed Description

In the following description of the present invention, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, and do not mean that the device must have a specific orientation. The text refers to the position close to the solid feed inlet as the back and the position close to the discharge outlet as the front.

In order to make the technical means, creation features, achievement purposes and functions of the present invention easy to understand and understand, the present invention is further explained by combining with the specific drawings.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

As shown in fig. 1 to 4, the utility model discloses a step tunnel type extraction tank includes box 1, and the rear end of box 1 is the feed end, and the front end is equipped with discharge gate 1d, and box 1 is inside to be the solvent environment, and each department such as connection face, flange all satisfies airtight requirement. The shell body is provided with an integral flange connecting surface, and the functions of strengthening the rigidity of the shell body, improving the manufacturing precision and improving the sealing and sealing are achieved. The inner cavity of the box body is provided with a plurality of stages of soaking units from front to back, the first stage of soaking unit is close to the discharge port 1d, and the last stage of soaking unit is positioned at the rear end of the box body.

Each stage of soaking unit comprises a soaking pool 3 and a baffle plate 4 respectively, the soaking pool 3 comprises a wallboard 3a, an arc-shaped bottom 3b and an inclined bottom plate 3c which are sequentially connected into a whole, the arc-shaped bottom 3b contains a lower shaft 7 of the stage, an upper shaft 8 of the stage is respectively positioned above the soaking pool of the previous stage, the upper end of the inclined bottom plate 3c extends towards the rear side of the upper shaft 8 of the stage, and the upper end of the wallboard 3a is connected below the inclined bottom plate 3c of the soaking pool of the next stage.

Lower shaft conveying chain wheels 7a are respectively installed at two ends of each level of lower shaft 7, and the bottom shapes of the arc-shaped bottom 3b and the lower shaft conveying chain wheels 7a are matched, so that the lower shaft conveying chain wheels 7a can freely rotate in the arc-shaped bottom 3b of the soaking pool.

The two ends of each level of upper shaft 8 are respectively provided with an upper shaft conveying chain wheel 8a, the conveying chain 9 is S-shaped and sequentially and alternately bypasses each level of lower shaft conveying chain wheel 7a and upper shaft conveying chain wheel 8a, and bypasses the first level of upper shaft conveying chain wheel 8a and then bypasses the last level of lower shaft conveying chain wheel 7a again through the feeding side guide slide rail 1j to form a closed loop, and scrapers are uniformly arranged along the perimeter of the conveying chain 9.

The inclined bottom plate 3c is parallel to a tangent line between the front side of the lower shaft conveying chain wheel 7a of the current stage and the rear side of the upper shaft conveying chain wheel 8a of the current stage, and the lower edge of the scraper plate moves downwards along the baffle plate 4 and moves upwards along the inclined bottom plate 3c.

The conveying chain 9 goes upward along a tangent line between the front side of the lower shaft conveying chain wheel of the current stage and the rear side of the upper shaft conveying chain wheel 8a of the current stage, and goes downward along a tangent line between the front side of the upper shaft conveying chain wheel 8a of the current stage and the rear side of the lower shaft conveying chain wheel of the previous stage. The planes of the axis of the lower shaft and the axis of the upper shaft of the stage are intersected with the inclined bottom plate and the baffle plate 4 of the stage at acute angles.

Taking six-stage extraction as an example, after a conveying chain 9 winds around a conveying chain wheel of a sixth-stage lower shaft from top to bottom, the conveying chain wheel turns to incline upwards and winds around a conveying chain wheel of a sixth-stage upper shaft, then turns to incline downwards and winds around a conveying chain wheel of a fifth-stage lower shaft, turns to incline upwards again and winds around a conveying chain wheel of a fifth-stage upper shaft, and so on, after the conveying chain wheel of the second-stage upper shaft is wound, the conveying chain 9 turns to incline downwards and winds around a conveying chain wheel of a first-stage lower shaft, turns to incline upwards again, enters a conveying chain wheel of a first-stage upper shaft, namely a discharging shaft after being turned by a discharging-side guide sliding rail 1k, enters an idle horizontal section to advance to a feeding side after being turned by a discharging-shaft conveying chain wheel, and then turns to downwards and winds around a conveying chain wheel of a sixth-stage lower shaft to form a closed loop. A horizontal supporting rail 1h is arranged below the conveying chain 9 of the no-load horizontal section.

The baffle plate 4 is a solid plate, is inserted in each soaking pool and is parallel to each level of inclined bottom plate 3c, the upper end of the baffle plate is higher than the liquid level, the lower end of the baffle plate extends into the lower part of the soaking pool, so that the extract liquor in the front part of the soaking pool is forced to bypass the lower edge of the baffle plate 4 and can reach the rear part of the soaking pool after being fully contacted and exchanged with the materials, and the length of the flow path of the extract liquor is prolonged. The upper layer low concentration extraction liquid is prevented from flowing backwards directly, the effective working path is long, and the short circuit phenomenon is avoided.

The baffle plates 4 at each stage have another function, and form a downward tunnel for materials with the lower end surface of the next-stage inclined bottom plate and form an upward tunnel for materials with the upper end surface of the previous-stage inclined bottom plate. The solvent and the solute are ensured to be in countercurrent contact in a tunnel formed by the inclined bottom plate of the soaking pool and the baffle plate 4, the tortuous tunnel limits the moving path of the solid material and the extract liquid, the frequency, the path and the time of the countercurrent contact of the solute and the solvent are increased, and the mass transfer process of the extraction is enhanced. The stepped tunnel type countercurrent soaking forms the preferential extraction process aiming at the powdery or semi-fluid solid material.

Two feed inlets are arranged at the rear part of the top wall of the box body, a solid material feed inlet 1a is arranged close to the rear side and is positioned above the final-stage baffle plate, and the feed inlets can be used for feeding solid materials. Solid material feed inlet 1a is equipped with the fill of keeping in, utilizes the fill accumulational material of keeping in to realize isolated with the atmosphere in the container, prevents that volatile solvent escapes in the container and leads to harm or loss.

The back upper place of last stage baffling board is equipped with feeding adjusting gate 2, can adjust the interval of gate height control and last stage baffling board to control the feeding volume, prevent that the feeding from out of control and leading to the tunnel siltation to block up. Usually, a shallow material layer is adopted for soaking and extraction, and the height of the material layer is controlled to be 100-400mm according to the properties of the materials.

The other feed inlet is a semi-fluid material feed inlet 1b, is positioned at the front side of the solid material feed inlet 1a and aims at semi-fluid materials with strong fluidity, such as thick paste materials and semi-slurry materials. A feeding platform 1c is arranged below the semi-fluid material feeding port 1b, and the feeding platform 1c is positioned above the last-stage upper shaft and can bear materials with strong flowability.

The continuous extraction generally adopts six-stage extraction, solid raw materials fall into a sixth-stage soaking pool through a solid material feed inlet 1a, are pushed by a scraper to descend along a sixth-stage baffle plate and are contacted with the concentrated mixed oil in the sixth-stage soaking pool, solid materials fall into an arc-shaped bottom 3b of the sixth-stage soaking pool from the bottom of the baffle plate, are fished and pushed by a chain scraper device, ascend along a sixth-stage inclined bottom plate and are separated from the liquid level, the solid materials are drained, free mixed oil in the solid materials is discharged and then falls onto a fifth-stage baffle plate from the sixth-stage inclined bottom plate, the solid materials are pushed by the scraper to descend along the fifth-stage baffle plate and are contacted with the concentrated mixed oil in the fifth-stage soaking pool, and the rest is done in a similar manner in turn, and continuous extraction is carried out. The number of stages can be increased properly for the materials which are difficult to extract.

The inclined bottom plate 3c is longer, is close to the upper shaft and obviously higher than the liquid level, and the inclined plate section higher than the liquid level is used for draining wet meal, so that the concentration content in the wet meal is reduced, the concentration gradient of each stage of soaking pool is obvious, and each stage of extraction has larger extraction power.

The inclined bottom plate 3c of each stage of soaking pool is provided with an obvious draining section, so that concentrated extraction liquid in solid materials is fully drained before the solid materials enter the next stage of soaking, concentration gradient is easily formed in each stage of soaking pool, and the extraction liquid is kept to have larger extraction power.

The upper end of the inclined bottom plate 3c can be higher than the horizontal plane of the axis of the upper shaft, so that the box body has a higher liquid level, a longer upward extraction stroke is provided along the inclined bottom plate 3c, the falling point is higher after the box body falls onto the previous stage baffle plate from the top of the inclined bottom plate 3c, and a longer downward extraction stroke is provided along the baffle plate 4.

The baffle plate of the stage extends from the front side of the upper shaft of the next stage to the top of the lower shaft 7 of the stage, the upper end of the baffle plate 4 can be close to the horizontal plane where the axis of the upper shaft is located, and a small amount of materials passing over the upper shaft chain wheel can also be received by the baffle plate 4 and enter the descending tunnel for extraction.

The upper parts of all levels of inclined bottom plates 3c except the first level are respectively provided with a filtering grid plate 3d, and the filtering grid plate 3d is of a structure with a narrow upper part and a wide lower part, so that blockage is avoided. The lower edge height of the previous stage of filtering grid plate is higher than that of the next stage of filtering grid plate in sequence, the position of the newly dissolved side filtering grid plate is highest, the positions of the filtering grid plates on the concentrated mixing side are gradually reduced, and the lower edges of the filtering grid plates 3d at each stage are higher than the top of the wallboard 3a of the previous stage of soaking pool.

Under the action of the interstage liquid level difference, the high-level extraction liquid on the low-concentration side penetrates through the filtering grid plate 3d and simultaneously penetrates through the solid materials on the filtering grid plate 3d, so that the solid materials are preliminarily washed, concentrated extraction liquid in the solid materials is replaced, the original concentration balance in the solid materials is broken, and the new mass transfer balance is favorably established when the solid materials enter the next stage for soaking.

At the upper part of each stage of the filtering grid plate 3d, the solid materials can be quickly drained. The filter grids 3d may extend to the top of the inclined bottom plate 3c, and may be provided in sections or integrally in the width direction of the inclined bottom plate 3c.

The inclined bottom plate of the first-stage soaking pool is not provided with a filtering grid plate, but is higher so as to be fully drained before discharging.

A new dissolution spraying pipe 11 is arranged above the first-stage soaking pool, a nozzle of the new dissolution spraying pipe 11 can be aligned with the juncture where the wet meal separated from the liquid level of the first-stage soaking pool, and the wet meal separated from the first-stage soaking pool is washed again by using new dissolution and then enters a final draining section. The new solution spraying pipe 11 can be arranged at the top of the box body and positioned above the conveying chain 9 at the no-load horizontal section, and the sprayed new solution can clean the conveying chain 9 and the scraper thereof and enter the next circulation.

Taking the sixth-stage extraction as an example, the fresh solvent is sprayed into the material ascending tunnel of the first-stage soaking tank, is fully mixed with the solid phase to be discharged for mass transfer, and then flows downwards in the reverse direction, enters the material descending tunnel of the first stage from the lower edge of the first-stage baffle plate and the bottom of the first-stage soaking tank, flows upwards along the material descending tunnel formed by the first-stage baffle plate and the second-stage inclined bottom plate, penetrates or permeates the solid material at the filtering grid plate section of the second-stage inclined bottom plate, enters the second-stage soaking tank, and so on, and finally flows into the sixth-stage soaking tank.

The inclined bottom plates of the soaking pools are uniformly provided with filtering grid plates 3d, and the self-flow is realized by utilizing the liquid level difference. The fresh solvent and the solid phase are in counter-current contact, the liquid level of the new solution side is at a high level because new solution is continuously injected, and the obvious liquid level difference is formed in the equipment because the set liquid level of the concentrated mixing side is at a low level, so that the liquid continuously permeates and flows from the high level to the low level. The side wall of the first-stage soaking pool is provided with a box body overflow port 1e for controlling the highest liquid level so as to ensure the safety.

A concentrated dissolution port 3e is arranged on the rear wall of the final-stage soaking pool, a baffle plate 5 stretching into the liquid level is arranged on the front side of the concentrated dissolution port 3e, the concentrated dissolution port 3e is separated from descending materials, a concentrated mixed settling area 6 is formed between the baffle plate 5 and the rear wall of the final-stage soaking pool, and concentrated dissolution is discharged after powder settling.

Each stage of extraction process of the materials comprises the following steps: soaking, solid-liquid mixing, fishing out, draining and the like. The highest concentration of solute in the new solid material is contacted with the highest concentration of concentrated solution, so that the new solid material has higher extraction power; the lowest concentration of solute in the solid material to be discharged is contacted with the new solution with the lowest concentration, the extraction power is still high, and finally the solid material is fully mixed with the fresh solvent in the first-stage soaking pool, then is fished up by a scraper and drained, and is discharged from a discharge port 1d.

The top of the box body is also provided with a free gas interface 1f and an access door 1g. The lowest position of the arc-shaped bottom 3b of each soaking pool is respectively provided with a vent, and each vent is connected into an emptying pipe 10, so that the air can be emptied conveniently during overhaul or batch replacement.

The foregoing is only a preferred and exemplary embodiment of the present invention, and the basic principles and main features of the present invention and the advantages of the present invention have been shown and described, without thereby limiting the scope of the present invention, which should be understood by those skilled in the art, and the present invention is not limited by the foregoing exemplary embodiments. In addition to the above embodiments, other embodiments of the present invention are also possible without departing from the spirit and scope of the present invention. The utility model discloses still can have various changes and improvements, all adopt to equate the technical scheme that replacement or equivalent transform formed, all fall in the utility model discloses the protection scope that requires. The scope of the invention is defined by the appended claims and equivalents thereof. The undescribed technical features of the present invention can be realized by or using the prior art, and are not described herein again.

Claims

1. The utility model provides a step tunnel type extraction tank, includes sealed box, the rear end of box is the feed end, and the front end is equipped with the discharge gate, and its characterized in that, box inner chamber are equipped with multistage soaking unit backward in the past, and first order soaking unit is close to the discharge gate, and soaking unit at different levels includes respectively:

a soaking pool: the device comprises a wall plate, an arc bottom and an inclined bottom plate which are sequentially connected into a whole, wherein the arc bottom accommodates a lower shaft of the stage, the upper end of the inclined bottom plate extends towards the rear side of an upper shaft of the stage, and the upper end of the wall plate is connected below the inclined bottom plate of a soaking pool of the next stage; the upper parts of all levels of inclined bottom plates except the first level are respectively provided with a filtering grid plate, and the heights of the lower edges of the filtering grid plates are gradually reduced from front to back and are all higher than the top of the wallboard;

2. The stepped tunnel extraction cell of claim 1, wherein: the baffle plate of the stage extends from the front side of the upper shaft of the next stage to the top of the lower shaft of the stage.

3. The stepped tunnel extraction cell of claim 1, wherein: the baffle plates at each stage and the lower end surface of the next-stage inclined bottom plate form a downward tunnel of materials, and the baffle plates at each stage and the upper end surface of the previous-stage inclined bottom plate form an upward tunnel of materials.

4. The stepped tunnel extraction cell of claim 1, wherein: the plane of the axis of the lower shaft of the stage and the plane of the axis of the upper shaft of the stage are intersected with the inclined bottom plate and the baffle plate of the stage at acute angles.

5. The stepped tunnel extraction cell of claim 1, wherein: the upper end of the inclined bottom plate is higher than the horizontal plane where the axis of the upper shaft is located, and the upper end of the baffle plate is close to the horizontal plane where the axis of the upper shaft is located.

6. The stepped tunnel extraction cell of claim 1, wherein: a new solution spraying pipe is arranged at the upper part of the front side of the box body, and the new solution is sprayed on the middle section of the inclined bottom plate of the first-stage soaking pool; the liquid level of the previous stage soaking pool is higher than that of the next stage soaking pool, a thick dissolving-out opening is formed in the rear wall of the last stage soaking pool, a baffle plate stretching into the liquid level is arranged on the front side of the thick dissolving-out opening, and a thick mixing settling zone is formed between the baffle plate and the rear wall of the last stage soaking pool.

7. The stepped tunnel extraction cell of claim 1, wherein: the side wall of the first-stage soaking pool is provided with a tank body overflow port for controlling the highest liquid level.

8. The stepped tunnel extraction cell of claim 1, wherein: a solid material feeding hole is formed in the rear part of the top wall of the box body and is positioned above the final-stage baffle plate; the feeding device is characterized in that a semi-fluid material feeding hole is formed in the front of the solid material feeding hole, a feeding platform is arranged below the semi-fluid material feeding hole, and the feeding platform is located above the last-stage upper shaft.

9. The stepped tunnel extraction cell of claim 1, wherein: and a feeding adjusting gate is arranged at the rear upper part of the final-stage baffle plate.