Production method of high-quality chemical gypsum

Abstract

The invention belongs to the technical field of inorganic materials, and particularly discloses a production method of high-quality chemical gypsum, which comprises the following steps: mixing and reacting a material 1 and a material 2, enabling turbid liquid at the upper part of a reactor to enter a clarification section, and taking clarified liquid as a salt and alkali making raw material or mining water; slurry at the bottom of the reactor enters a gypsum slurry collecting system, the gypsum slurry is subjected to primary separation through a cyclone, the top of the gypsum slurry flows back to a reaction barrel to participate in recycling, and the bottom of the gypsum slurry flows to a primary slurry dewatering washing machine; the treated filter material enters a pulping and washing barrel, the washed slurry enters a secondary dewatering washing machine, and the filter material is directly packaged into a product after being moderately refined, or is packaged into a product after being crushed and dried. The gypsum prepared by the process method is high in purity, excellent in whiteness and stable and controllable in quality.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic materials, relates to the production of gypsum, and particularly relates to a method for producing high-quality chemical gypsum by using mirabilite-type brine and calcium chloride-type brine. Background Art

[0002] Gypsum is divided into natural gypsum and chemically synthesized gypsum. Natural gypsum refers to gypsum stone (minerals whose main components are calcium sulfate dihydrate or anhydrous calcium sulfate) contained in nature, mainly sediments of ancient salt lakes or lagoons. It is usually white, sometimes gray, light yellow, slightly reddish or light brown due to impurities, and is an important non-metallic mineral resource. Although my country's reserves of natural gypsum are very rich, the proportion of high-quality natural gypsum is very small, and as the national environmental protection policy becomes more and more stringent, the scope and intensity of its mining are greatly limited, which invisibly affects the supply of high-quality gypsum market. Chemically synthesized gypsum, also known as industrial by-product gypsum, is a by-product produced in the industrial production process with calcium sulfate dihydrate (CaSO4·2H2O) as the main component, called industrial by-product gypsum, such as phosphogypsum, flue gas desulfurization gypsum, citric acid gypsum, titanium gypsum, etc. Due to the presence of a large amount of impurities, industrial by-product gypsum has problems such as low purity, poor whiteness, or odor, and its application scenarios are greatly limited. Phosphogypsum and desulfurization gypsum have been gradually developed and utilized by people, with large fluctuations in quality and generally limited to low-level applications in the construction industry.

[0003] Therefore, it is urgent to develop a process method to provide high-quality chemical gypsum with high purity and good whiteness to replace high-quality natural gypsum, so as to solve the problem of shortage of natural resources and meet the demand of the high-quality gypsum market. Summary of the invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for producing high-quality chemical gypsum. The present invention is based on the existing salt and nitrate making industries, and adopts ammonia-soda method alkali-making calcium clearing liquid or calcium chloride brine containing calcium ions and nitrate brine with different sodium sulfate contents as raw materials. Through the setting of the process, gypsum with high purity and excellent whiteness is obtained, and the quality is stable and controllable.

[0005] The present invention is achieved through the following technical solutions: A method for producing high-quality chemical gypsum comprises the following steps: (1) After the material 1 providing the calcium source and the material 2 providing the sulfate ion are mixed and stirred in a reactor, the slurry at the bottom of the reactor continuously enters the gypsum slurry barrel or the clarification barrel, and the turbid liquid at the top of the reactor continuously enters the clarification barrel; (2) After the turbid liquid continues to react and clarify in the clarification tank, the underflow is continuously discharged into the gypsum slurry tank in an appropriate amount. The slurry concentration (referring to the volume concentration of calcium sulfate dihydrate) in the gypsum slurry tank is controlled at 10-35%; the overflow enters the storage tank of the reaction completion liquid to be recycled; (3) The slurry in the gypsum slurry is transferred to the cyclone, and the top flow of the cyclone returns to the reaction barrel; the bottom flow is sent to the washing and dehydrating machine, and the slurry concentration is controlled at 30-60%; (4) Using a washing and dehydrating machine, the slurry is graded and filtered, rinsed with fresh water and filtered 2-3 times, and the filter material is transferred to a fresh water washing bucket with an agitator for washing; (5) The slurry in the washing barrel is transferred to the cyclone. Part of the top flow of the cyclone returns to the waste water barrel and part is discharged to the slag injection system; the bottom flow is sent to the washing and dehydrating machine. The slurry concentration is controlled at 40-60%; (6) Use a washing and dehydrating machine to dehydrate the slurry and rinse it with fresh water and washing water for no less than 3 times, and then transfer the filtered material to a screw feeder with a disperser; (7) The material is fed evenly into the low-temperature dryer through a screw feeder, and the dried material enters the collecting hopper of the flash dryer; then it is transferred to the finished product high-level silo and packaged individually into finished products; if the moisture content is kept low, it can be packaged directly without entering the dryer.

[0006] A further improvement of the present invention is: The material 1 is selected from the ammonia-soda process alkali-making and calcium-clearing liquid or the calcium chloride-type brine prepared with the calcium-clearing liquid, or a mixture of the two; the main components of the alkali-making and calcium-clearing liquid are 35-65g / l sodium chloride and 80-120g / l calcium chloride, and the main components of the prepared calcium chloride-type brine are 240-295g / l sodium chloride and 15-80g / l calcium chloride.

[0007] Further, the material 2 is selected from one or more of Glauber's salt type brine, salt making mother liquor produced in the process of making salt using Glauber's salt type brine, high nitrate brine or nitrate brine with different sodium sulfate contents. The main components of the Glauber's salt type brine are 280-305g / l sodium chloride and 10-35g / l sodium sulfate; the main components of the salt making mother liquor are 270-295g / l sodium chloride and 35-65g / l sodium sulfate; the main components of the nitrate brine are 150-330g / l sodium sulfate and 20-150g / l sodium chloride; the main components of the high nitrate brine are 150-280g / l sodium chloride and 65-150g / l sodium sulfate. Further, the "calcium-sulfur ratio" (referring to the molar ratio of calcium chloride to sodium sulfate) of material 1 and material 2 is 1:1.2~1.8.

[0008] Furthermore, the stirring reaction time in step (1) is 15-120 minutes; and the reaction time in step (2) is 5-15 hours.

[0009] Furthermore, in step (4), the mother liquor after filtration is collected in a filtrate bucket and then pumped back to the reactor; the waste liquid after filtration after fresh water elution is collected in a wastewater bucket and can be intermittently transferred to the workshop sewage treatment system.

[0010] Furthermore, in step (6), the filtered waste liquid is collected in a waste liquid barrel, part of which is returned to the reactor and part of which is discharged to the slag injection system.

[0011] Furthermore, the moisture content of the filter material in step (4) and step (6) is lower than 20%.

[0012] Compared with the prior art, the present invention has the following beneficial effects: Since the intrinsic quality of synthetic dihydrate gypsum raw materials is relatively stable, and the feeding method, proportion, stirring intensity, reaction time, separation method, washing times, etc. are all controllable, the quality of synthetic gypsum is relatively stable.

[0013] The process method of the present invention can organize production continuously and on a large scale, and the quality of the product is stable and controllable; the purity and whiteness of the product are better than all by-product gypsum, and can replace the first-grade and above natural stone raw materials.

[0014] The comprehensive utilization rate of resources in the present invention is higher, the reaction product is washed and purified into a high-quality product, the reaction completion liquid can also be used as a general industrial brine raw material, and the wastewater generated in the washing process is used as a water medium for mining. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a process flow chart of embodiments 1 to 8 of the present invention; Figure 2 Process flow chart for embodiments 7 to 16 of the present invention DETAILED DESCRIPTION

[0016] The present invention is described in detail below in conjunction with specific embodiments. Example 1

[0017] The process flow chart of this embodiment is as follows Figure 1 : Step 1: Put material 1 - the alkali-calcium clearing liquid made by the ammonia-soda method (sodium chloride 35-65g / l, calcium chloride 80-120g / l) as material 1 into the calcium source barrel; and put material 2 - the salt-making mother liquor (sodium chloride 270-280g / l, sodium sulfate 35-65g / l) into the nitrate source barrel.

[0018] Step 2: Mix material 1 and material 2 from the calcium source barrel and the nitrate source barrel according to a calcium-sulfur ratio of 1:1.5, and put them into a reactor with an agitator. Control the reaction at 55-75 minutes at room temperature, and continuously discharge the slurry from the bottom of the reactor into a gypsum slurry barrel (equipped with a stirring mechanism), and the solid-liquid ratio of the slurry is controlled at 10-35%; continuously discharge the turbid liquid from the top of the reactor into a clarification barrel, continue to react in the clarification barrel for 5-15 hours, and then clarify; after clarification, continuously discharge the bottom flow of the clarification barrel into the gypsum slurry barrel in an appropriate amount, and the solid-liquid ratio is controlled at 10-35%; the overflow of the clarification barrel enters the storage barrel of the reaction completion liquid as the raw material for other processes.

[0019] Step 3: Use the transfer pump 1 to transfer the slurry in the gypsum slurry 2 to the cyclone 1. The top flow of the cyclone 1 returns to the reaction barrel (the particle size of fine particles is less than 5 mm); the bottom flow is fed to the washing and dehydrating machine 1, and the slurry concentration is controlled at 40-60%.

[0020] Step 4: Use the washing and dehydrating machine 1 to grade and filter the slurry, rinse with fresh water and filter 2-3 times; the filtered mother liquor is collected in the filtrate bucket and then pumped back to the reaction bucket; the filtered waste liquid after fresh water rinsing is collected in the wastewater bucket 1, which can be intermittently transferred to the workshop slag injection system; the filter material (water content is controlled below 20%) is transferred to the fresh water washing bucket with a stirrer for washing.

[0021] Step 5: After washing, the slurry in the washing barrel is transferred to the cyclone 2 by using the transfer pump 2. The top flow of the cyclone 2 can be partially returned to the waste water barrel 1 and partially discharged to the slag injection system (the particle size of fine particles is less than 5 mm); its bottom flow is fed to the washing and dehydrating machine 2, and the concentration is controlled at 40-60%; the slurry is dehydrated by using the washing and dehydrating machine 2 and rinsed with fresh water and washing water for no less than 3 times; the filtered liquid is collected in the waste liquid barrel 1, or partially discharged to the slag injection system; the filter material (the moisture content is controlled below 20%) is transferred to the screw feeder 1 with a disperser.

[0022] Step 6: The filtered material from the spiral feeder 1 is evenly fed into the dryer, and the dried material enters the collecting hopper of the flash dryer; then it is transferred to the finished product high-level silo through the spiral feeder 2 or the bucket elevator 1, and then packaged into various finished products; the powder of the dust removal system is finally collected in the powder silo (the moisture content of the powder is controlled below 8%), and can be packaged separately into finished products.

[0023] The gypsum products produced by this process can have a moisture content of attached water below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 2

[0024] In this embodiment, the ammonia-soda process alkali-calcification solution (sodium chloride 35-65 g / l, calcium chloride 80-120 g / l) is used as material 1, and high nitrate brine (sodium chloride 150-280 g / l, sodium sulfate 65-15 g / l) is used as material 2, and other operations are roughly the same as those in Example 1.

[0025] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 3

[0026] In this embodiment, ammonia-soda process alkali-calcium clearing liquid (sodium chloride 35-65 g / l, calcium chloride 80-120 g / l) is used as material 1, nitrate brine (sodium sulfate 150-330 g / l, sodium chloride 20-15 g / l) is used as material 2, and other operations are roughly the same as those in Example 1.

[0027] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 4

[0028] In this embodiment, the ammonia-soda process alkali-calcification solution (sodium chloride 35-65 g / l, calcium chloride 80-120 g / l) is used as material 1, and the mirabilite-type brine (sodium chloride 280-305 g / l, sodium sulfate 10-35 g / l) is used as material 2. Other operations are roughly the same as those in Example 1.

[0029] The gypsum product produced in this embodiment has a moisture content (adherent water) that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 5

[0030] In this embodiment, calcium chloride brine (sodium chloride 240-295 g / l, calcium chloride 15-80 g / l) is used as material 1, and salt-making mother liquor (sodium chloride 270-280 g / l, sodium sulfate 35-65 g / l) is used as material 2. Other operations are roughly the same as those in Example 1.

[0031] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 6

[0032] In this embodiment, calcium chloride brine (sodium chloride 240-295g / l, calcium chloride 15-80g / l) is used as material 1, and high nitrate brine (sodium chloride 150-280g / l, sodium sulfate 65-150g / l) is used as material 2. Other operations are roughly the same as those in Example 1.

[0033] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 7

[0034] In this embodiment, calcium chloride brine (sodium chloride 250-260g / l, calcium chloride 60-75g / l) is used as material 1, nitrate brine (sodium chloride 240-15g / l, sodium sulfate 100-330g / l) is used as material 2, and other operations are roughly the same as those in Example 1.

[0035] The gypsum products produced by this process can have a moisture content of attached water below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 8

[0036] In this embodiment, calcium chloride type brine (sodium chloride 250-260g / l, calcium chloride 60-75g / l) is used as material 1, and sodium salt type brine (sodium chloride 280-305g / l, sodium sulfate 10-35g / l) is used as material 2. Other operations are roughly the same as those in Example 1.

[0037] The gypsum products produced by this process can have a moisture content of attached water below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 9

[0038] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 1. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 1.

[0039] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 10

[0040] The process flow chart of this embodiment is as follows Figure 2As shown, the raw materials in this embodiment are the same as those in Example 1. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 1.

[0041] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Embodiment 11

[0042] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 2. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 2.

[0043] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 12

[0044] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 3. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 3.

[0045] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 13

[0046] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 4. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 4.

[0047] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Embodiment 14

[0048] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 5. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 5.

[0049] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Embodiment 15

[0050] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 6. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 6.

[0051] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Example 16

[0052] The process flow chart of this embodiment is as follows Figure 2 As shown, the raw materials in this embodiment are the same as those in Example 7. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 7.

[0053] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis). Embodiment 17

[0054] The process flow chart of this embodiment is as follows Figure 2As shown, the raw materials in this embodiment are the same as those in Example 8. The bottom and overflow of the materials after the reaction in the reactor both enter the clarification tank, and the overflow and bottom flow rate are determined according to the needs of material balance control. The turbid liquid entering the clarification tank is clarified and subsequently reacted for 5-15 hours, and then the bottom flow of the clarification tank is continuously discharged into the gypsum slurry tank in an appropriate amount. Other operations are roughly the same as those in Example 8.

[0055] The gypsum product produced in this embodiment has a moisture content of attached water that can be controlled below 10%, a chloride ion content of ≤200ppm, and a calcium sulfate dihydrate content of ≥98% (dry basis).

[0056] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for producing high-quality chemical gypsum, characterized in that: The following steps are involved: (1) After mixing and stirring the material 1 providing the calcium source and the material 2 providing the sulfate ion in the reactor, the turbid liquid at the top of the reactor continuously enters the clarification tank, and the slurry at the bottom of the reactor is intermittently or continuously discharged into the gypsum slurry tank; (2) After the turbid liquid continues to react and clarify in the clarification tank, the underflow is continuously discharged into the gypsum slurry tank in an appropriate amount. The slurry concentration in the gypsum slurry tank is controlled at 10-35%; the overflow enters the storage tank of the reaction completed liquid to be recycled; (3) The slurry in the gypsum slurry barrel is transferred to the cyclone, and the top flow of the cyclone returns to the reaction barrel; the bottom flow is sent to the first-level dehydration washing machine, and the slurry concentration is controlled at 30-60%; (4) Using a primary dehydration washing machine, the slurry is graded for dehydration and fresh water washing, and the filter material is transferred to a fresh water washing bucket with an agitator for washing; (5) The slurry in the washing tank is transferred to the cyclone for solid-liquid analysis, and the top flow of the cyclone is returned to the waste water tank or discharged to the waterless treatment system; Its underflow goes to the secondary dewatering washing machine, and the pulp concentration is controlled at 30-60%; (6) Use a secondary washing and dehydrating machine to grade and dehydrate the slurry, rinse it with fresh water, and transfer the filter material to a screw feeder with a disperser; (7) The material is fed evenly into the low-temperature dryer through a screw feeder. The material enters the collecting hopper after the moderate dryer; then it is transferred to the finished product high-level silo and individually packaged into finished products.

2. The method for producing high-quality chemical gypsum according to claim 1, characterized in that: The material 1 is selected from the ammonia-soda process alkali-making and calcium-clearing liquid or the calcium chloride-type brine prepared with the calcium-clearing liquid, or a mixture of the two; the main components of the alkali-making and calcium-clearing liquid are 35-65g / l sodium chloride and 80-120g / l calcium chloride, and the main components of the prepared calcium chloride-type brine are 240-295g / l sodium chloride and 15-80g / l calcium chloride.

3. The method for producing high-quality chemical gypsum according to claim 1, characterized in that: The material 2 is selected from one or more of Glauber's salt brine, salt-making mother liquor produced in the process of making salt using Glauber's salt brine, high nitrate brine or nitrate brine with different sodium sulfate contents; the main components of the Glauber's salt brine are 280-305g / l sodium chloride and 10-35g / l sodium sulfate; the main components of the salt-making mother liquor are 270-295g / l sodium chloride and 35-65g / l sodium sulfate; the main components of the nitrate brine are 150-330g / l sodium sulfate and 20-150g / l sodium chloride; the main components of the high nitrate brine are 150-280g / l sodium chloride and 65-150g / l sodium sulfate.

4. A method for producing high-quality chemical gypsum according to any one of claims 1 to 3, characterized in that: Material 1 and material 2 are fed in a calcium-sulfur ratio of 1:0.8~1.

6.

5. The method for producing high-quality chemical gypsum according to claim 1, characterized in that: The stirring reaction time in step (1) is 15-120 minutes; the subsequent reaction and clarification time in step (2) is 5-15 hours.

6. The method for producing high-quality chemical gypsum according to claim 1, characterized in that: In step (4), the filtered liquid is collected in a filtrate bucket and then pumped back to the reactor; the waste liquid after fresh water washing is collected in a wastewater bucket and can be intermittently transferred to the workshop waterless treatment system.

7. The method for producing high-quality chemical gypsum according to claim 1, characterized in that: In steps (5) and (6), the filtered liquid is collected in a waste liquid bucket, and the waste liquid after washing is discharged into a waterless treatment system.

8. The method for producing high-quality chemical gypsum according to claim 1, characterized in that: The moisture content of the filter material in step (4) and step (6) is both lower than 20%.

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