Salt pan system for solar evaporation of brine

Abstract

The present application relates to a salt field for spreading brine, comprising a plurality of salt ponds (1), a brine inlet channel (2) and a brine outlet channel (3). The brine inlet channel (2) is arranged on one side of a salt pond group (10) and is in communication with each salt pond (1) in the salt pond group (10) and is provided with a brine inlet gate (22). The brine inlet channel (2) is also provided with a brine guide gate (23) corresponding to each salt pond (1) at intervals. The brine outlet channel (3) is arranged on the other side of the salt pond (1) and is in communication with each salt pond (1) in the salt pond group (10) and is provided with a brine outlet gate (32) to control the on-off of the brine. Therefore, by using the brine inlet channel (2), the brine outlet channel (3), and the brine inlet gate (22), the brine guide gate (23) and the brine outlet gate (32) arranged corresponding to the salt pond (1), the brine can be injected into a single salt pond for spreading under special circumstances, avoiding the effect of brine mixing, which is beneficial to improve the yield of potassium chloride and prevent too much sodium chloride from accumulating and occupying the space of the sodium salt pond.

Description

Technical Field

[0001] This invention relates to potash fertilizer production technology in salt fields, and more particularly to the structure of a salt field ore drying system for spreading brine. Background Technology

[0002] The main process of potash fertilizer production is as follows: extracting intercrystalline brine (commonly known as raw brine) from salt lake strata, transporting it to large artificially constructed salt ponds (commonly known as salt fields), and using solar energy for natural evaporation and drying. First, some sodium chloride is evaporated to obtain mineralized brine (commonly known as E-brine). Then, the mineralized brine is dried to obtain carnallite (KCl·MgCl2·6H2O) ore. Potassium chloride (KCl) is extracted from the carnallite ore using chemical processes such as crystallization and flotation. Finally, potash fertilizer can be produced.

[0003] Salt pan drying is a crucial step in potash fertilizer production. Currently, salt pans are structured by connecting multiple salt ponds according to elevation. As the brine flows through these ponds (a process known as "flow"), moisture evaporates until potassium chloride, a raw material for potash fertilizer, precipitates at the final pond. To improve drying efficiency, for example, a salt pan drying system for carnallite, disclosed in patent number 202010884666.3, arranges the brine inlets and outlets of adjacent carnallite ponds (salt ponds) diagonally, ensuring the brine flows diagonally during the water flow process. This salt pan structure facilitates brine flow, increases water evaporation, and achieves balanced ore drying.

[0004] However, the structure of this salt field presents problems, especially in the following two situations:

[0005] 1. When the potassium and magnesium content in the extracted brine is too low, the brine dilution caused by different brine concentrations in different salt ponds will alter the mineral composition precipitated in downstream salt ponds, resulting in a significant decrease in potassium chloride production and potassium chloride loss. Furthermore, when the potassium and magnesium content in the raw brine is low while the sodium content is high, a large amount of sodium chloride will precipitate during the spreading and drying process. This sodium chloride will occupy space in the salt ponds, leading to a significant reduction in the brine storage capacity of the salt fields.

[0006] 2. At low temperatures (≤5℃), water evaporation is low, resulting in a slow mineralization rate. Therefore, to obtain E-brine, it is necessary to increase the number of salt ponds, extend the water flow route, and increase the drying time, which seriously wastes salt field space and human and material resources. Furthermore, at low temperatures, the problem of sodium chloride occupying the brine storage capacity of the salt field becomes even more severe.

[0007] With the deepening development of salt lake resources, the increase in potash fertilizer production capacity, and the implementation of solid-liquid conversion, the above-mentioned situation frequently occurs during the salt field spreading process. Because the existing structure of salt fields requires the newly entering brine to drive the water flow during the spreading process, the water flow cannot be interrupted. Furthermore, the spreading cycle of salt lake brine is long and difficult to quantify, making it difficult to make adjustments when the above situation occurs. Summary of the Invention

[0008] The purpose of this invention is to solve the problem that existing salt fields are difficult to adjust when encountering situations such as poor brine quality or low temperature, which leads to sodium chloride occupying the salt pond's capacity, changes in the mineral composition precipitated from the brine during evaporation, and waste of salt field space.

[0009] To achieve the above objectives, the present invention provides a salt field drying system for spreading brine, comprising multiple salt ponds 1, which are connected according to the terrain elevation, and a water gate 4 is provided between adjacent salt ponds 1 to control the flow of brine. It also includes a brine inlet ditch 2, a brine inlet pumping station 21, a brine outlet ditch 3, and a brine outlet pumping station 31.

[0010] The brine inlet ditch 2 is located on one side of each salt pond 1 and is connected to the interior of each salt pond 1. A brine inlet gate 22 is set at the connection point 20 to control the flow of brine. A brine guide gate 23 is set at the position corresponding to each salt pond 1 to control the flow of brine.

[0011] The brine pumping station 21 is located at the front end of the brine inlet ditch 2 and is used to pump brine into the brine inlet ditch 2.

[0012] The brine outlet ditch 3 is located on the other side of each salt pond 1 and is connected to each salt pond 1 in the salt pond group 10. A brine outlet gate 32 is set at the connection point to control the flow of brine.

[0013] The brine pumping station 31 is located at the rear end of the brine discharge ditch 3 and is used to pump out the brine from the brine discharge ditch 3.

[0014] Therefore, when encountering situations such as poor brine quality or low temperature, all water gates 4 are closed, and each salt pond 1 is used for independent drying. That is, by controlling the brine guiding gate 23 and brine inlet gate 22 of each salt pond 1, the brine is directed into each salt pond 1 for separate drying. There is no water flow between the salt ponds 1, which avoids the brine dilution effect and the resulting changes in the minerals precipitated during drying, thus improving potassium chloride production.

[0015] Once the brine composition in a single salt pond 1 reaches the preset value, the sodium chloride at the bottom of salt pond 1 can be cleaned to prevent excessive accumulation of sodium chloride and its occupation of space in the sodium salt pond.

[0016] Since the brine can be controlled to enter different salt ponds 1 for drying to the required components by using gates such as the brine inlet ditch 2 and the brine inlet gate 22, there is no need to deliberately extend the water flow route. This allows for more flexible adjustment of the water storage capacity of the salt ponds 1 according to production needs, which is conducive to the rational use and adjustment of the salt field space.

[0017] Preferably, the brine pumping station 21 pumps the raw brine into the brine inlet ditch 2, the salt pool 1 in the salt pool group 10 dries the raw brine into mineralized brine, and the brine outlet pumping station 31 pumps the mineralized brine out.

[0018] Due to naturally formed K + Na + Mg 2+ Cl - The / H2O quaternary system salt lake brine, as the original brine, falls in the sodium chloride crystallization phase region and is far from point E. Therefore, at low temperatures, the sodium salt pond faces more serious problems such as sodium chloride occupying the salt pond space and the brine dilution effect causing changes in the minerals precipitated from the brine during evaporation. This invention can effectively solve the above problems.

[0019] Preferably, the brine inlet ditch 2 and the brine outlet ditch 3, like each salt pond 1, form a downward slope, that is, after the brine enters the brine inlet ditch 2 and the brine outlet ditch 3, it can flow backward by gravity.

[0020] Preferably, the salt ponds 1 are arranged in two rows, forming two salt pond groups 10. The two salt pond groups 10 are set in parallel and share a brine inlet ditch 2 and a brine inlet pump station 21, or a brine outlet ditch 3 and a brine outlet pump station 31. When the air temperature is >5℃ and the brine quality is good, the brine is spread out for drying in either salt pond group 10 using a continuous water flow method. At the same time, the salt deposits in the other salt pond group 10 can be cleaned or collected.

[0021] Preferably, two water gates 4 are installed between adjacent salt ponds 1, with the two water gates 4 located on the left and right sides of the salt pond 1 respectively. When the air temperature is >5℃ and the brine quality is good, one of the water gates 4 is opened, allowing the brine to fill each salt pond 1. Driven by the newly pumped brine, the brine flows continuously along the diagonal of each salt pond 1. The staff uses the water gates 4 to adjust the flow rate, controlling the composition of the last salt pond 1 to reach a preset value, and then discharges it through the brine discharge pump station 31. Attached Figure Description

[0022] Figure 1 This is a structural diagram illustrating the salt field sun-drying system used for spreading brine.

[0023] Figure 2 This is an enlarged illustration of the salt ponds and surrounding structures in the salt field ore drying system;

[0024] Figure 3 This is an explanatory diagram of the salt field ore drying system used for water-based drying.

[0025] Figure 4 This is an illustration of introducing brine into each salt pond during individual evaporation.

[0026] Figure 5 This is a structural illustration of a salt field sun-drying system used for spreading brine, as a variation.

[0027] Attached reference numerals: 1-Salt pool; 10-Salt pool group; L-Centerline L; 2-Inlet brine ditch; 4-Water gate; 21-Inlet brine pumping station; 22-Inlet brine gate; 23-Guide brine gate; 3-Outlet brine ditch; 31-Outlet brine pumping station; 32-Outlet brine gate. Detailed Implementation

[0028] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The following description is a specification of the claims of the present invention.

[0029] Example 1

[0030] Figure 1 This is a structural diagram illustrating the salt pan drying system used for spreading brine. Figure 2 This is an enlarged illustration of the salt ponds and surrounding structures in the salt field ore drying system; the following is combined with... Figure 1 , 2 The structure of the salt field sun-drying system used for spreading brine is described.

[0031] like Figure 1 As shown, the salt field sun-drying system for spreading brine includes multiple salt ponds 1, brine inlet ditches 2, brine inlet pumping stations 21, brine outlet ditches 3, and brine outlet pumping stations 31.

[0032] Multiple salt ponds 1 are connected in sequence according to the terrain elevation to form a salt pond group 10. Two water gates 4 are set at the edge of adjacent salt ponds 1 to control the flow of brine.

[0033] Each salt pond 1 has a brine inlet ditch 2 and a brine outlet ditch 3 on both sides of the pond. A brine inlet pump station 21 is installed at the front end of the brine inlet ditch 2 to pump brine into the brine inlet ditch 2, and the end of the brine inlet ditch 2 is closed.

[0034] The front end of the brine outlet ditch 3 is closed, and the end is equipped with a brine outlet pump station 31 to pump out the brine in the brine outlet ditch 3.

[0035] like Figure 2As shown on the upper side, the brine inlet channel 2 and each salt pool 1 in the salt pool group 10 are separated by a first pool wall 20. A brine inlet channel 24 is provided on the first pool wall 20 to connect the brine inlet channel 2 with the interior of the salt pool 1. A brine inlet gate 22 is provided on the brine inlet channel 24 to control the flow of brine. That is, when the brine inlet gate 22 is open, the brine inlet channel 24 is open, the brine inlet channel 2 is connected with the interior of the salt pool 1, and brine can be put into the salt pool 1 through the brine inlet channel 2; when the brine inlet gate 22 is closed, the brine inlet channel 2 is closed, the brine inlet channel 2 is not connected with the salt pool 1, and the brine in the brine inlet channel 2 cannot enter the salt pool 1.

[0036] like Figure 2 As shown on the upper side, the brine inlet channel 2 is equipped with brine guide gates 23 at the positions of each salt pond 1 in the salt pond group 10 to control the flow of brine. Combined with the brine inlet gates 22 corresponding to each salt pond 1, the brine can be controlled to enter any salt pond 1. For example, see... Figure 4 Open the brine guide gate 23a corresponding to the first salt pool 1 on the left, close the brine guide gate 23b corresponding to the second salt pool 1 on the left, close the brine inlet gate 22a on the wall of the first salt pool 1 on the left, and open the brine inlet gate 22b on the wall of the second salt pool 1 on the left, so that the brine (shaded part in the figure) can only enter the second salt pool 1 on the left.

[0037] like Figure 2 As shown on the lower side, the brine outlet ditch 3 is separated from each salt pool 1 in the salt pool group 10 by a second pool wall 30. A brine outlet channel 34 is provided on the second pool wall 30 to connect the brine outlet ditch 3 to the interior of the salt pool 1. A brine outlet gate 32 is provided on the brine outlet channel 34 to control the flow of brine. That is, when the brine outlet gate 32 is open, the brine outlet channel 34 is open, the brine outlet ditch 3 is connected to the interior of the salt pool 1, and the brine in the salt pool 1 can exit through the brine outlet ditch 3; when the brine outlet gate 32 is closed, the brine outlet channel 34 is closed, the brine outlet ditch 3 is not connected to the salt pool 1, and the brine in the salt pool 1 cannot enter the brine outlet ditch 3.

[0038] The brine inlet channel 2 and the brine outlet channel 3 each have a downward slope, allowing the brine to flow within them by gravity after entering. Both the inlet channel 2 and the outlet channel 3 are U-shaped or trapezoidal channels rather than pipes, which prevents the brine from accumulating salt and causing blockages.

[0039] From the side of the salt lake, that is, from Figure 2 Looking at the direction indicated by the small arrow b, the brine inlet ditch 2, the salt pond 1, and the brine outlet ditch 3 have a gradient from high to low. Therefore, after opening the brine inlet gate 22, the brine can flow from the brine inlet ditch 2 to the salt pond 1 by gravity; after opening the brine outlet gate 32, the brine in the salt pond 1 can flow out from the brine outlet ditch 3 by gravity.

[0040] like Figure 2As shown, there are two water gates 4 between adjacent salt ponds 1. The two water gates 4 are far from the center line L of the salt pond group 10, that is, the two water gates 4 are located near the left and right sides of the two ponds respectively. One of them needs to be opened alternately when water flows. This process is similar to a salt field sun-drying system for brine stones disclosed in invention patent No. 202010884666.3, and will not be described in detail here.

[0041] Figure 3 This is an explanatory diagram of the salt pan drying system used for drying ore on water-covered surfaces. Figure 4 This is an illustrative diagram illustrating the introduction of brine into each salt pond during individual evaporation. The following diagram is combined with... Figure 3 , 4 The following explains two different forms of sun-drying processes:

[0042] 1. When the air temperature is >5℃ and the brine quality is good (i.e., the brine evaporates quickly and the brine dilution effect has little impact on the subsequent precipitated minerals), continuous water flow is used for sun-drying in the salt fields.

[0043] like Figure 3 As shown, all brine inlet gates 22 are closed, and the brine is pumped into the first salt pond 1 on the left using the brine inlet pump station 21. One of the outflow gates 4 is opened, allowing the brine to flow continuously along the diagonal of each salt pond 1 for drying. During the outflow process, workers can use the outflow gates 4 to adjust the outflow speed and control the brine concentration in each salt pond until the brine composition in the last salt pond 1 reaches the preset value. Then, it is discharged through the outflow pump station 31 and the outflow ditch 3.

[0044] This continuous water-flow drying method is easy to control, minimizes manual labor under the condition of rapid brine evaporation, and maximizes production capacity.

[0045] 2. When the brine evaporates rapidly and the brine dilution effect leads to a significant reduction in potassium chloride precipitation during subsequent drying, all water gates 4 should be closed, and each salt pond 1 should be used for independent drying. That is, by controlling the brine guiding gate 23 and brine inlet gate 22 of each salt pond 1, the brine is directed into each salt pond 1 for separate drying. There is no water flow between the salt ponds 1.

[0046] For example, Figure 4As shown, taking the second salt pond 1 on the left as an example, first open the first brine guide gate 23a on the left and close the second brine guide gate 23b on the left. Then open the brine inlet gate 22b corresponding to the second salt pond 1 on the left and close the other brine inlet gates 22. Close all water outlet gates 4 and brine outlet gates 32. The brine is then pumped into the brine inlet ditch 2 by the brine inlet pump station 21. The brine enters the second salt pond 1 on the left after passing through the first brine guide gate 23a on the left and the brine inlet gate 22b corresponding to the second salt pond 1 on the left. When the brine in the second salt pond 1 on the left reaches the upper limit liquid level, the brine inlet gate 22b corresponding to the second salt pond 1 on the left is closed. The other salt ponds are similarly introduced with brine for sun-drying.

[0047] This method of spreading and drying each salt pond individually avoids the brine dilution effect caused by differences in brine concentration and substances. It also prevents changes in the mineral composition of the brine during the subsequent spreading and drying process in the subsequent salt ponds when the brine is flowed in series, which is beneficial to improving the yield of potassium chloride.

[0048] When the brine composition in salt pond 1 reaches the preset value after being spread out and dried, the brine outlet gate 32 corresponding to each salt pond 1 is opened to discharge the brine through the outlet ditch 3. Afterwards, the sodium chloride at the bottom of salt pond 1 can be cleaned to prevent excessive accumulation of sodium chloride and its occupation of space in the sodium salt pond.

[0049] Since the brine can be controlled to enter different salt ponds 1 for drying to the required components by using gates such as the brine inlet ditch 2 and the brine inlet gate 22, there is no need to deliberately extend the water flow route. This allows for more flexible adjustment of the water storage capacity of the salt ponds 1 according to production needs, which is conducive to the rational use and adjustment of the salt field space.

[0050] Because the temperature is high and the water evaporates quickly when salt ponds are dried individually, a portion of salt pond 1 can be selected for drying, while the remaining salt ponds are used to remove deposited sodium chloride. This alternating use of different salt ponds 1 allows for simultaneous drying of the brine and removal of deposited sodium chloride, maximizing efficiency.

[0051] Variation Example 1

[0052] Figure 5 This is a structural illustration of a salt field used for spreading brine in Modified Example 1. The structure of Modified Example 1 is basically the same as that of Example 1, except that:

[0053] like Figure 5 As shown, the salt ponds 1 are arranged in two rows, forming two salt pond groups 10. The two salt pond groups 10 are set in parallel and share the brine inlet ditch 2 and the brine inlet pump station 21.

[0054] When the temperature is above 5℃ and the brine quality is good, the brine is spread out for drying in either of the two salt pond groups 10 using a continuous water flow method. At the same time, the salt deposits in the other salt pond group 10 can be cleaned or collected.

[0055] When the temperature is ≤5℃ and / or the brine quality is poor, the brine is spread out in a single pool storage form. That is, the brine is transported to any salt pool 1 for spreading out using the common brine pumping station 21 and brine ditch 2. When the brine composition reaches the preset value, the brine is discharged using the brine discharge ditch 3 and brine discharge pumping station 31 adjacent to the salt pool 1.

[0056] The salt field structure provided by this invention utilizes the brine inlet ditch 2, the brine outlet ditch 3, and the brine inlet gate 22, brine guide gate 23, and brine outlet gate 32 set in the corresponding salt pond 1. This allows the brine to be injected into any single salt pond for sun-drying when the original brine quality is poor or the temperature is low. This avoids the brine dilution effect from altering the minerals precipitated during brine sun-drying, and is beneficial for increasing potassium chloride production.

[0057] Once the brine composition in a single salt pond 1 reaches the preset value, the sodium chloride at the bottom of salt pond 1 can be cleaned to prevent excessive accumulation of sodium chloride and its occupation of space in the sodium salt pond.

[0058] Since the brine can be controlled to enter different salt ponds 1 for drying to the required components by using gates such as the brine inlet ditch 2 and the brine inlet gate 22, there is no need to deliberately extend the water flow route. This allows for more flexible adjustment of the water storage capacity of the salt ponds 1 according to production needs, which is conducive to the rational use and adjustment of the salt field space.

[0059] It should also be noted that, due to naturally formed K + Na + Mg 2 Cl - The / H2O quaternary system brine, as the primary brine, falls within the sodium chloride crystallization phase region and is relatively far from point E. Therefore, at lower temperatures, the problems of sodium chloride occupying salt pond space and the alteration of minerals precipitated during brine evaporation due to the brine dilution effect become more severe in sodium salt ponds. Therefore, the salt field structure of this invention is currently preferred for K... + Na + Mg 2+ Cl - The sodium salt pool of the / H2O quaternary system salt lake brine, namely, the brine inlet pump station 21 is used to pump the raw brine, the salt pool 1 in the salt pool group 10 dries the raw brine into mineralized brine (E brine), and the brine outlet pump station 31 pumps the mineralized brine out to the regulating pool or carnallite pool.

[0060] In addition, judging from the development of salt lake brine in recent years, with the deepening of mining, the increase in potash fertilizer production capacity and the implementation of solid-liquid conversion, the quality of the original brine spread in salt fields has gradually deteriorated (potassium and magnesium content has decreased, while sodium content has continued to rise). Therefore, the carnallite pool of this invention has a very good application prospect.

Claims

1. A salt field drying system for spreading brine, comprising multiple salt ponds (1), wherein the salt ponds (1) are connected according to their elevation, and a water gate (4) is provided between adjacent salt ponds (1) to control the flow of brine, characterized in that, It also includes the brine inlet ditch (2), the brine inlet pump station (21), the brine outlet ditch (3), and the brine outlet pump station (31). The brine inlet ditch (2) is located on one side of each of the salt ponds (1) and communicates with the interior of each of the salt ponds (1). A brine inlet gate (22) is provided at the communication point (20) to control the flow of brine. A brine guide gate (23) is provided at the position corresponding to each of the salt ponds (1) to control the flow of brine. The brine pumping station (21) is located at the front end of the brine inlet ditch (2) and is used to pump brine into the brine inlet ditch (2). The brine outlet ditch (3) is located on the other side of each of the salt ponds (1), and is connected to each of the salt ponds (1) in the salt pond group (10). A brine outlet gate (32) is provided at the connection point to control the flow of brine. The brine pumping station (31) is located at the rear end of the brine outlet ditch (3) and is used to pump out the brine from the brine outlet ditch (3). The brine is K. + Na + Mg 2+ Cl - The / H2O quaternary system salt lake brine, the brine inlet pumping station (21) pumps the raw brine into the brine inlet ditch (2), the salt ponds (1) in the salt pond group (10) turn the raw brine into mineralized brine, and the brine outlet pumping station (31) pumps the mineralized brine out. When the temperature is >5℃ and the brine quality is good, close all brine inlet gates (22), use brine inlet pump station (21) to pump the brine into the first salt pool (1) on the left, open the water outlet gate (4) on one side, so that the brine flows continuously along the diagonal of each salt pool (1) to dry the brine. When the temperature is ≤5℃ or the brine quality is poor, close all the water gates (4), control the brine guide gates (23) and brine inlet gates (22) of each salt pond (1), and introduce the brine into each salt pond (1) separately for drying.

2. The salt field ore drying system for spreading brine according to claim 1, characterized in that, The brine inlet ditch (2) and the brine outlet ditch (3) also have a downward slope, just like each of the salt ponds (1).

3. The salt field sun-drying system for spreading brine according to claim 1, characterized in that, The salt ponds (1) are arranged in two rows, forming two salt pond groups (10). The two salt pond groups (10) are set up in parallel and share a brine inlet ditch (2) and brine inlet pump station (21) or a brine outlet ditch (3) and brine outlet pump station (31).

4. The salt field sun-drying system for spreading brine according to any one of claims 1 to 3, characterized in that, Two water gates (4) are provided between adjacent salt ponds (1), and the two water gates (4) are located near the left and right sides of the salt ponds (1) respectively.

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