A continuous calcium-magnesium-iron impurity removal device for producing potassium sulfate by mirabilite method

Abstract

The utility model discloses a kind of continuous calcium magnesium iron impurity removal devices for mirabilite method production potassium sulfate, comprising: reaction tank;Stirring assembly one is assembled on the reaction tank, and the stirring assembly one is used to stir and guide raw material;Cooling coil is fixedly installed on the reaction tank, and the cooling coil is used to cool solution;The effect of above-mentioned device is that new material is directly guided to the bottom of reaction tank by the action of flow guide cylinder, avoid new material and the premature contact of floating impurities in upper portion of tank body, to improve reaction efficiency and impurity removal effect.Raw material in reaction tank is fully stirred and mixed under the action of stirring assembly one.Stirring assembly one is rotated by servo motor driving stirring shaft one, ensure that reactant material is uniformly mixed, promote reaction to fully carry out, realize the continuous high-efficiency removal of calcium magnesium iron and other impurities in the process of mirabilite method production potassium sulfate, with significant technical advantage and economic benefit.

Description

Technical Field

[0001] This utility model relates to the field of potassium sulfate production by the Glauber's salt process, and more specifically, to a continuous calcium, magnesium and iron impurity removal device for potassium sulfate production by the Glauber's salt process. Background Technology

[0002] Currently, there are three main potassium sulfate production processes in China: First, the Mannheim process, which involves reacting potassium chloride and sulfuric acid at high temperatures (500-600 ℃) in a Mannheim furnace to obtain potassium sulfate. The HCl gas produced is absorbed by a tail gas recovery device to obtain hydrochloric acid as a byproduct. This process causes severe corrosion to equipment and poses significant environmental risks. Furthermore, the sale of the byproduct hydrochloric acid directly impacts potassium sulfate production. The resulting potassium sulfate, produced under acidic conditions, contains relatively high levels of free acid and chloride ions. Second, the ammonium sulfate process, where the disposal of the byproduct ammonium chloride affects potassium sulfate production. Third, the resource-based method, which involves direct separation and extraction from salt lakes. This method produces products with many impurities and restricts the exploitation of salt lakes.

[0003] The method for producing potassium sulfate using the Glauber's salt process involves reacting Glauber's salt with potassium chloride to first generate potassium Glauber's salt (Na₂SO₄·3K₂SO₄) and a first-phase mother liquor (also called potassium Glauber's salt mother liquor), as shown in equation (1). Then, the separated potassium Glauber's salt is further reacted with potassium chloride to generate potassium sulfate and sodium chloride, as shown in equations (2) and (3). The potassium sulfate is then obtained through separation and drying. The theoretical basis for producing potassium sulfate using the Glauber's salt conversion method is 2K₂SO₄·3K₂SO₄·2 ... + 2Na + / / 2Cl - SO4 2- —H₂O quaternary aqueous salt system phase diagram. Crystallization separation is performed based on the differences in solubility of various salts at different temperatures. KCl, NaCl, K₂SO₄, and Na₂SO₄ form a quaternary aqueous salt system with water, where NaCl and K₂SO₄, and Na₂SO₄ and KCl are salt pairs. At any temperature, the crystallization regions of potassium sulfate and sodium chloride are not adjacent. Therefore, potassium chloride and sodium sulfate must undergo a two-stage conversion to produce potassium sulfate.

[0004] The chemical reaction is as follows:

[0005] Na2SO4 + KCl + H2O → Na2SO4·3K2SO4 + Mother liquor (also called potassium sulfate mother liquor) (1)

[0006] Na2SO4·3K2SO4 + KCl + H2O→ K2SO4 + Secondary mother liquor (also called potassium mother liquor) (2)

[0007] First-stage mother liquor → NaCl + salt mother liquor + H2O (3)

[0008] The main raw materials for producing potassium sulfate via the Glauber's salt conversion process are Glauber's salt, potassium chloride, and water, and the entire production system is a closed loop. The water entering the system mainly consists of evaporation condensate from the dissolution of potassium chloride during the secondary conversion process and crystal water carried in by the raw material Glauber's salt. The water leaving the system is primarily evaporation condensate. Theoretically, the entire system can only operate stably when these two components reach equilibrium. In practice, the raw material potassium chloride conforms to the national standard GB6549-2011. This product is neutral, but during purification, it retains small amounts of impurities such as calcium chloride, magnesium chloride, ammonium chloride, and octadecane quaternary ammonium salt. These impurities accumulate and undergo phase changes in the production system (the production system is a sulfate system, while calcium sulfate is only slightly soluble), forming floating impurities. In severe cases, scaling occurs on the heat exchanger surface, significantly impacting normal production operations. Furthermore, due to the presence of ammonium salts, a hydrolysis equilibrium exists during the evaporation process, with ammonium ions moving towards free ammonia. During the high-temperature evaporation stage, free ammonia volatilizes along with the steam, causing a decrease in the pH of the evaporation system. This, in turn, exacerbates the corrosion of production equipment, which is detrimental to production safety. Octadecane quaternary ammonium salt is a potassium salt flotation agent, which easily produces floating matter. Therefore, from both the perspective of product quality and production stability, the removal of impurities such as calcium and magnesium is imperative.

[0009] Research revealed that some people use a single-phase mother liquor for deep impurity removal. The method involves adding liquid alkali to the single-phase mother liquor for deep impurity removal, which can reduce the magnesium ion concentration in the solution to 10 ppm. However, the resulting magnesium hydroxide precipitate has a small particle size and a large specific surface area, resulting in poor dispersibility in water or other media and easy formation of agglomerates, which makes the filtration process difficult. Utility Model Content

[0010] In order to overcome the above-mentioned defects of the prior art, this utility model provides a continuous calcium, magnesium and iron impurity removal device for potassium sulfate production by the Glauber's salt process, so as to solve the problem that the fine magnesium hydroxide precipitate particles are difficult to filter.

[0011] To solve the above-mentioned technical problems, this utility model provides the following technical solution: a continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production using the Glauber's salt process, comprising: a reaction tank; a stirring assembly one mounted on the reaction tank, the stirring assembly one being used for stirring and guiding the raw materials; a cooling coil fixedly installed on the reaction tank, the cooling coil being used for cooling the solution; a raw material transfer assembly mounted on the reaction tank, the raw material transfer assembly being used for controlling the input and output of the solution; a steel tank frame mounted on one side of the reaction tank, the steel tank frame being equipped with a stirring assembly two, the stirring assembly two being used for stirring and sedimentation; an inclined tube device mounted on the steel tank frame, the inclined tube device being used for filtration and controlling the mother liquor flow rate; and a thickening assembly mounted on the steel tank frame, the thickening assembly being used for thickening the solution.

[0012] Preferably, the stirring assembly includes: a servo motor fixedly mounted on the reaction vessel, a stirring shaft fixedly mounted on the drive end of the servo motor, a mounting bracket fixedly mounted inside the reaction vessel, a guide tube fixedly mounted on one end of the mounting bracket, and a feed inlet fixedly mounted on the reaction vessel.

[0013] Preferably, the raw material transfer assembly includes: a mother liquor outlet fixedly installed at the top of the reaction tank, a purification port fixedly installed on one side of the reaction tank, and a bottom liquid outlet fixedly installed at the bottom of the reaction tank.

[0014] Preferably, the second stirring assembly includes: a working bridge frame fixedly installed on the steel tank frame, a geared motor fixedly installed on the working bridge frame, a second stirring shaft fixedly installed on the drive end of the geared motor, and a stirring rake fixedly installed on the outer surface of the second stirring shaft.

[0015] Preferably, the inclined tube device is fixedly installed on the steel pool frame, and the steel pool frame is provided in two sets, with the two sets of steel pool frames symmetrically arranged on the steel pool frame.

[0016] Preferably, the thickening component includes: a hopper fixedly installed on the steel tank frame, a rake frame fixedly installed inside the hopper, an anti-sway device fixedly installed at the bottom of the second stirring shaft, and a bottom outlet fixedly installed at the bottom of the hopper.

[0017] Preferably, the mother liquor is discharged from the mother liquor outlet and then fed into the inclined tube device for secondary processing.

[0018] Preferably, the feed inlet is located inside the guide tube, and the feed inlet is used to input the raw liquid.

[0019] Compared with the prior art, the beneficial effects of this utility model are:

[0020] This invention introduces material into the reaction tank through an inlet located inside a guide tube. The guide tube directs the incoming material directly to the bottom of the reaction tank, preventing premature contact between the material and floating impurities in the upper part of the tank, thus improving reaction efficiency and impurity removal. The raw materials entering the reaction tank are thoroughly mixed by a stirring assembly. This assembly, driven by a servo motor, rotates a stirring shaft to ensure uniform mixing and promote a complete reaction. Simultaneously, cooling coils fixed inside the reaction tank cool the reaction system, controlling the reaction temperature within a suitable range to prevent side reactions or equipment corrosion due to excessive heat. During the reaction, impurities such as calcium, magnesium, and iron in the raw materials gradually form insoluble precipitates that float in the upper part of the reaction tank. At this point, the mother liquor containing potassium sulfate is discharged through the mother liquor outlet at the top of the reaction tank, proceeding to the next processing stage. Heavier impurities deposited at the bottom of the reaction tank are discharged through the bottom liquid outlet. In addition, a removal port is provided on one side of the reaction vessel to periodically remove accumulated floating impurities, keeping the interior of the reaction vessel clean and ensuring long-term stable operation. The device design in Example 1 enables continuous production, avoiding the inefficiency problems associated with traditional intermittent operation. The guiding effect of the flow guide effectively reduces the mixing of new materials with impurities, improving reaction efficiency and impurity removal. Simultaneously, the temperature control function of the cooling coils ensures stable reaction, reduces the risk of equipment corrosion, and extends equipment lifespan.

[0021] This invention achieves more efficient solid-liquid separation and impurity removal by adding an inclined tube device and a thickening component. The mother liquor discharged from the mother liquor outlet of the reaction tank first enters the inclined tube device for secondary treatment. The inclined tube device contains a large number of densely arranged inclined tubes or plates. The mother liquor flows slowly upward within the device, and fine particulate impurities settle to the bottom of the inclined tubes under gravity and slide down to the bottom of the device for centralized discharge. The clarified liquid after treatment by the inclined tube device flows out from the upper overflow port and enters the next processing stage. Subsequently, the clarified liquid enters the thickening component for further thickening treatment. The thickening component is mounted on a steel tank frame and contains a hopper and a rake. The geared motor of the second stirring component drives the second stirring shaft and the stirring rake to rotate, slowly stirring the material in the hopper and promoting the sedimentation and thickening of solid particles. The concentrated slurry deposited at the bottom of the hopper is discharged through the underflow port, while the clarified liquid at the top can be reused or used in subsequent processes. In addition, an anti-sway device is installed at the bottom of the second stirring shaft to prevent the stirring shaft from swaying during operation and ensure stable equipment operation. The device design in Example 2, through the combined action of the inclined tube device and the thickening component, significantly improves the removal efficiency of impurities such as calcium, magnesium, and iron, ensuring the purity and whiteness of the potassium sulfate product. Simultaneously, the shallow sedimentation principle of the inclined tube device effectively reduces the equipment footprint and improves space utilization. The further processing by the thickening component ensures thorough solid-liquid separation, reduces the load on subsequent processes, and improves the operating efficiency and stability of the entire production system. In summary, the device designs in Examples 1 and 2 both achieve continuous and efficient removal of impurities such as calcium, magnesium, and iron during the sodium sulfate production process, demonstrating significant technical advantages and economic benefits. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the impurity separation structure of the reaction vessel of this utility model;

[0023] Figure 2 This is a schematic diagram of the inclined plate settler structure of this utility model;

[0024] Figure 3 This is a schematic diagram of the stirring assembly and the raw material transfer assembly of this utility model.

[0025] Figure 4 This is a schematic diagram of the second stirring component of this utility model;

[0026] Figure 5 This is a schematic diagram of the dense component structure of this utility model.

[0027] [Figure Labels]

[0028] 1. Reaction vessel; 2. Stirring assembly one; 3. Cooling coil; 4. Raw material transfer assembly; 5. Steel tank frame; 6. Stirring assembly two; 7. Inclined tube device; 8. Thickening assembly; 201. Servo motor; 202. Stirring shaft one; 203. Mounting bracket; 204. Flow guide tube; 205. Feed inlet; 401. Mother liquor outlet; 402. Impurity removal port; 403. Bottom liquid outlet; 601. Working bridge; 602. Gear motor; 603. Stirring shaft two; 604. Stirring rake; 801. Hopper; 802. Rake frame; 803. Anti-sway device; 804. Bottom flow port. Detailed Implementation

[0029] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this utility model. Example

[0030] A preferred embodiment of the continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process provided by this invention is, for example... Figures 1 to 5 As shown, it includes: a reaction vessel 1; a stirring assembly 2 mounted on the reaction vessel 1, the stirring assembly 2 being used to stir and guide the raw materials; a cooling coil 3 fixedly installed on the reaction vessel 1, the cooling coil 3 being used to cool the solution; a raw material transfer assembly 4 mounted on the reaction vessel 1, the raw material transfer assembly 4 being used to control the input and output of the solution; a steel tank frame 5 mounted on one side of the reaction vessel 1, the steel tank frame 5 being equipped with a second stirring assembly 6, the second stirring assembly 6 being used for stirring and sedimentation; an inclined tube device 7 mounted on the steel tank frame 5, the inclined tube device 7 being used for filtration and controlling the mother liquor flow rate; and a thickening assembly 8 mounted on the steel tank frame 5, the thickening assembly 8 being used to thicken the solution.

[0031] In this embodiment, the stirring assembly 2 includes: a servo motor 201 fixedly installed on the reaction vessel 1, a stirring shaft 202 fixedly installed on the drive end of the servo motor 201, an installation bracket 203 fixedly installed inside the reaction vessel 1, a guide tube 204 fixedly installed at one end of the installation bracket 203, and a feed inlet 205 fixedly installed on the reaction vessel 1.

[0032] In this embodiment, the raw material transfer component 4 includes: a mother liquor outlet 401 fixedly installed on the top of the reaction tank 1, a purification outlet 402 fixedly installed on one side of the reaction tank 1, and a bottom liquid outlet 403 fixedly installed at the bottom of the reaction tank 1.

[0033] In actual production, the raw materials first enter the reaction tank 1 through the feed inlet 205 located inside the guide tube 204. The function of the guide tube 204 is to guide the newly fed material directly to the bottom of the reaction tank 1, avoiding premature contact between the newly fed material and floating impurities in the upper part of the tank, thereby improving reaction efficiency and impurity removal effect. The raw materials entering the reaction tank 1 are thoroughly stirred and mixed by the stirring assembly 2. The stirring assembly 2 is driven by the servo motor 201 to rotate the stirring shaft 202, ensuring uniform mixing of the reactants and promoting a complete reaction. At the same time, the cooling coil 3 fixedly installed inside the reaction tank 1 cools the reaction system, controlling the reaction temperature within a suitable range to avoid side reactions or equipment corrosion caused by excessive temperature. During the reaction, impurities such as calcium, magnesium, and iron in the raw materials gradually form insoluble precipitates, which float in the upper part of the reaction tank 1. At this time, the mother liquor containing potassium sulfate is discharged through the mother liquor outlet 401 located at the top of the reaction tank 1 and enters the next processing stage. Heavier impurities deposited at the bottom of reaction tank 1 are discharged from the tank through the bottom liquid outlet 403. In addition, a removal port 402 is provided on one side of reaction tank 1 to periodically remove accumulated floating impurities, keeping the interior of reaction tank 1 clean and ensuring long-term stable operation. The device design in Example 1 achieves continuous production, avoiding the inefficiency problems of traditional intermittent operation. The guiding effect of the guide tube 204 effectively reduces the mixing of new materials with impurities, improving reaction efficiency and impurity removal effect. Simultaneously, the temperature control function of the cooling coil 3 ensures stable reaction, reduces the risk of equipment corrosion, and extends equipment lifespan. Example

[0034] Based on Example 1, a preferred embodiment of the continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process provided by this invention is, for example... Figures 1 to 5 As shown: The stirring assembly 6 includes: a working bridge 601 fixedly installed on the steel tank frame 5, a reduction motor 602 fixedly installed on the working bridge 601, a stirring shaft 603 fixedly installed on the drive end of the reduction motor 602, and a stirring rake 604 fixedly installed on the outer surface of the stirring shaft 603.

[0035] In this embodiment, the inclined tube device 7 is fixedly installed on the steel pool frame 5. The steel pool frame 5 is provided in two sets, and the two sets of steel pool frames 5 are symmetrically arranged on the steel pool frame 5.

[0036] In this embodiment, the thickening component 8 includes: a hopper 801 fixedly installed on the steel tank frame 5, a rake frame 802 fixedly installed inside the hopper 801, an anti-sway device 803 fixedly installed at the bottom of the stirring shaft 603, and a bottom outlet 804 fixedly installed at the bottom of the hopper 801.

[0037] In this embodiment, the mother liquor outlet 401 outputs the mother liquor and then inputs it into the inclined tube device 7 for secondary processing.

[0038] In this embodiment, the feed inlet 205 is located inside the guide tube 204, and the feed inlet 205 is used to input the raw liquid.

[0039] Based on Example 1, Example 2 further adds an inclined tube device 7 and a thickening assembly 8 to achieve more efficient solid-liquid separation and impurity removal. The mother liquor discharged from the mother liquor outlet 401 of the reaction tank 1 first enters the inclined tube device 7 for secondary treatment. The inclined tube device 7 has a large number of densely arranged inclined tubes or plates inside. The mother liquor slowly rises and flows within the inclined tube device 7, and fine particulate impurities settle to the bottom of the inclined tubes under gravity and slide down the inclined tubes to the bottom of the device for centralized discharge. The clear liquid after treatment by the inclined tube device 7 flows out from the upper overflow port and enters the next processing stage. Subsequently, the clear liquid enters the thickening assembly 8 for further thickening treatment. The thickening assembly 8 is installed on the steel tank frame 5 and has a hopper 801 and a rake frame 802 inside. The reduction motor 602 of the stirring assembly 6 drives the stirring shaft 603 and the stirring rake 604 to rotate, slowly stirring the material in the hopper 801 to promote the settling and thickening of solid particles. The concentrated slurry deposited at the bottom of hopper 801 is discharged through underflow port 804, while the clarified liquid at the top can be reused or used in subsequent processes. Furthermore, an anti-sway device 803 is installed at the bottom of the second stirring shaft 603 to prevent swaying during operation and ensure stable equipment operation. The device design in Example 2, through the combined action of the inclined tube device 7 and the thickening component 8, significantly improves the removal efficiency of impurities such as calcium, magnesium, and iron, ensuring the purity and whiteness of the potassium sulfate product. Simultaneously, the shallow sedimentation principle of the inclined tube device 7 effectively reduces the equipment footprint and improves space utilization. The further processing by the thickening component 8 ensures thorough solid-liquid separation, reduces the load on subsequent processes, and improves the overall operating efficiency and stability of the production system. In summary, the device designs in Examples 1 and 2 both achieve continuous and efficient removal of impurities such as calcium, magnesium, and iron during the sodium sulfate production process, demonstrating significant technical advantages and economic benefits.

[0040] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0041] Secondly: The accompanying drawings of the embodiments disclosed in this utility model only involve the structures involved in the embodiments disclosed in this utility model. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this utility model can be combined with each other.

[0042] Finally: The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process, characterized in that, include: Reaction vessel (1); A stirring assembly (2) is mounted on the reaction vessel (1), the stirring assembly (2) being used to stir and guide the raw materials; A cooling coil (3) is fixedly installed on the reaction vessel (1), and the cooling coil (3) is used to cool the solution; A raw material transfer assembly (4) is mounted on the reaction vessel (1), the raw material transfer assembly (4) being used to control the input and output of the solution; A steel tank frame (5) is assembled on one side of the reaction tank (1), and a stirring assembly (6) is assembled on the steel tank frame (5). The stirring assembly (6) is used for stirring and sedimentation. An inclined tube device (7) is mounted on the steel tank frame (5), the inclined tube device (7) being used for filtration and controlling the mother liquor flow rate; A thickening assembly (8) is mounted on the steel tank frame (5) for thickening the solution.

2. The continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 1, characterized in that, The stirring assembly (2) includes: A servo motor (201) is fixedly installed on the reaction vessel (1). A stirring shaft (202) is fixedly installed on the drive end of the servo motor (201). An installation bracket (203) is fixedly installed inside the reaction vessel (1). A guide tube (204) is fixedly installed at one end of the installation bracket (203). A feed inlet (205) is fixedly installed on the reaction vessel (1).

3. The continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 1, characterized in that, The raw material transfer component (4) includes: A mother liquor outlet (401) is fixedly installed on the top of the reaction tank (1), a purification port (402) is fixedly installed on one side of the reaction tank (1), and a bottom liquid outlet (403) is fixedly installed at the bottom of the reaction tank (1).

4. A continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 1, characterized in that, The stirring assembly two (6) includes: A working bridge (601) is fixedly installed on the steel pool frame (5). A geared motor (602) is fixedly installed on the working bridge (601). A stirring shaft (603) is fixedly installed on the drive end of the geared motor (602). A stirring rake (604) is fixedly installed on the outer surface of the stirring shaft (603).

5. A continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 1, characterized in that, The inclined tube device (7) is fixedly installed on the steel pool frame (5). The steel pool frame (5) is provided in two sets, and the two sets of steel pool frames (5) are symmetrically arranged on the steel pool frame (5).

6. A continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 4, characterized in that, The dense component (8) includes: A hopper (801) is fixedly installed on the steel tank frame (5). A rake frame (802) is fixedly installed inside the hopper (801). An anti-sway device (803) is fixedly installed at the bottom of the stirring shaft (603). A bottom outlet (804) is fixedly installed at the bottom of the hopper (801).

7. A continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 3, characterized in that, The mother liquor outlet (401) outputs the mother liquor and then inputs it into the inclined tube device (7) for secondary processing.

8. A continuous calcium, magnesium, and iron impurity removal device for potassium sulfate production via the Glauber's salt process according to claim 2, characterized in that, The feed inlet (205) is located inside the guide tube (204) and is used to input the raw liquid.

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