A processing system for calcium and magnesium-containing leaching solution by-product of chemical beneficiation

Abstract

The utility model discloses a chemical ore dressing byproduct's calcium magnesium containing leaching solution processing system, including leaching solution pretreatment subsystem, magnesium oxide production subsystem and nitric acid circulation subsystem, leaching solution pretreatment subsystem includes the decalcification reaction tank, filter press, evaporimeter, mixer and concentration tower that connect gradually, magnesium oxide production subsystem includes centrifugal separation device, dewatering device and pyrogenation device that connect gradually, centrifugal separation device is connected with concentration tower, nitric acid circulation subsystem includes bleaching tower, cooler, finished product nitric acid storage tank and condenser, bleaching tower with concentration tower is connected, cooler and condenser with bleaching tower is connected, finished product nitric acid storage tank with cooler is connected. The utility model discloses a chemical ore dressing byproduct's calcium magnesium containing leaching solution processing system can realize calcium magnesium effective separation, improve product utilization value, reduce pollution and recover nitric acid.

Description

Technical Field

[0001] This utility model relates to the field of chemical mineral processing by-product treatment technology, specifically to a calcium- and magnesium-containing leaching solution treatment system for chemical mineral processing by-products. Background Technology

[0002] With the development of chemical beneficiation technology, the comprehensive utilization of calcium-magnesium leaching solution, a byproduct of the chemical beneficiation process, has received increasing attention. Calcium-magnesium leaching solution is typically obtained from pressure filtration separation during the preparation of low-magnesium phosphate concentrate from medium- and low-grade phosphate rock, and contains a large amount of valuable elements such as calcium and magnesium. How to efficiently recover these valuable elements and achieve comprehensive resource utilization is currently a hot research topic.

[0003] Traditional processing methods, due to the lack of separation of calcium and magnesium, result in a magnesium-containing calcium carbonate mixture with low utilization value, significantly limiting its application. Furthermore, practical production is difficult, with low filtrate conversion rates and unstable product content, making it impossible to effectively utilize the currently produced magnesium-containing calcium carbonate. In addition, nitric acid in the magnesium nitrate solution is often not effectively recovered during the processing, leading to resource waste and environmental pollution. Therefore, how to effectively treat calcium-magnesium leaching solutions, improve product utilization value, and simultaneously recover nitric acid has become an urgent technical problem to be solved. Utility Model Content

[0004] In order to overcome the shortcomings of the existing technology, this utility model provides a calcium-magnesium leaching solution treatment system for chemical mineral processing by-products, which can achieve effective separation of calcium and magnesium, improve the utilization value of products, reduce pollution and recover nitric acid.

[0005] The technical solution adopted by this utility model to solve its technical problem is:

[0006] A system for treating calcium- and magnesium-containing leaching solutions, a byproduct of chemical mineral processing, includes a leaching solution pretreatment subsystem, a magnesium oxide production subsystem, and a nitric acid circulation subsystem. The leaching solution pretreatment subsystem comprises a decalcification reaction tank, a filter press, an evaporator, a mixer, and a concentration tower connected in sequence. The concentration tower includes a stripping section and a rectification section, with the feed end of the rectification section connected to the top discharge end of the stripping section. The magnesium oxide production subsystem includes a centrifugal separator, a dehydration device, and a pyrolysis device connected in sequence, with the feed end of the centrifugal separator connected to the bottom discharge end of the stripping section. The nitric acid circulation subsystem includes a bleaching tower, a cooler, a finished nitric acid storage tank, and a condenser. The feed end of the bleaching tower is connected to the discharge end of the rectification section. The feed ends of the cooler and condenser are respectively connected to the liquid discharge end and gas discharge end of the bleaching tower. The feed end of the finished nitric acid storage tank is connected to the discharge end of the cooler.

[0007] The decalcification reaction vessel is used to receive calcium-magnesium leaching solution and magnesium sulfate solution and to perform decalcification treatment on the calcium-magnesium leaching solution.

[0008] The filter press is used to filter the products from the decalcification reaction vessel to obtain filter cake and filtrate;

[0009] The evaporator is used to evaporate and crystallize the filtrate filtered by the filter press;

[0010] The mixer is used to receive the dilute nitric acid solution and the product of the evaporator and to mix and react the two.

[0011] The concentration tower is used to receive the product of the mixer. The concentration tower includes a stripping section and a rectification section. The stripping section is used to further concentrate the nitric acid vapor obtained from the reaction in the mixer and then send it to the rectification section, where the rectification section further concentrates the nitric acid vapor.

[0012] The centrifugal separation device is used to separate the solid-liquid mixture obtained from the reaction in the mixer and transported in the stripping section.

[0013] The dehydration device is used to heat the solid magnesium nitrate obtained by the centrifugal separation device;

[0014] The pyrolysis device is used to process the anhydrous magnesium nitrate obtained from the dehydration device;

[0015] The bleaching tower is used to bleach the nitric acid vapor output from the rectification section;

[0016] The cooler is used to cool the hot nitric acid liquid obtained from the bleaching tower;

[0017] The condenser is used to cool the nitric acid vapor output from the pyrolysis tower.

[0018] As a further improvement to the above technical solution, the leaching solution pretreatment subsystem also includes a magnesium sulfate dissolving tank, and the feed end of the decalcification reaction tank is connected to the discharge end of the magnesium sulfate dissolving tank.

[0019] As a further improvement to the above technical solution, the leaching solution pretreatment subsystem further includes a first cleaning device and a second cleaning device. The feed end of the first cleaning device is connected to the solid discharge end of the filter press, the feed end of the second cleaning device is connected to the solid discharge end of the first cleaning device, the liquid discharge end of the first cleaning device is connected to the feed end of the magnesium sulfate dissolving tank, and the liquid discharge end of the second cleaning device is connected to the feed end of the first cleaning device.

[0020] As a further improvement to the above technical solution, the leaching solution pretreatment subsystem further includes a dilute magnesium tank, the feed end of which is connected to the liquid discharge end of the filter press, and the discharge end of which is connected to the feed end of the evaporator.

[0021] As a further improvement to the above technical solution, the discharge end of the centrifugal separation device is connected to the feed end of the magnesium sulfate dissolving tank and the dilute magnesium tank.

[0022] As a further improvement to the above technical solution, the leaching solution pretreatment subsystem also includes a magnesium concentration tank, the feed end of which is connected to the discharge end of the evaporator, and the discharge end of which is connected to the feed end of the mixer.

[0023] As a further improvement to the above technical solution, the gas outlet of the pyrolysis device is connected to the feed end of the rectification section.

[0024] As a further improvement to the above technical solution, the gas outlet end of the pyrolysis device is connected to a recovery chamber, which is used to recover the gas generated by the pyrolysis device.

[0025] As a further improvement to the above technical solution, the nitric acid circulation subsystem also includes a distribution valve, the discharge end of the condenser is connected to the distribution valve, and the feed end of the rectification section and the feed end of the bleaching tower are respectively connected to the two discharge ends of the distribution valve.

[0026] As a further improvement to the above technical solution, the nitric acid circulation subsystem also includes a dilution tank, the discharge end of the condenser is connected to the inlet end of the dilution tank, and the discharge end of the dilution tank is connected to the inlet end of the mixer.

[0027] The beneficial effects of this invention are: the device of this invention can separate calcium and magnesium leaching solution, a byproduct of chemical mineral processing, to obtain calcium sulfate, magnesium oxide and nitric acid, thereby achieving effective separation of calcium and magnesium, obtaining calcium sulfate, magnesium oxide and nitric acid, improving the utilization value of the product and reducing pollution. Attached Figure Description

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Figure 1 This is a structural block diagram of a calcium-magnesium leaching solution treatment system for a byproduct of chemical mineral processing in Embodiment 1 of this utility model;

[0030] Figure 2 This is a structural block diagram of a calcium-magnesium leaching solution treatment system for a byproduct of chemical mineral processing in Embodiment 2 of this utility model;

[0031] Figure 3 This is a structural block diagram of a calcium-magnesium leaching solution treatment system for a byproduct of chemical mineral processing, as described in Embodiment 3 of this utility model.

[0032] Reference numerals in the attached diagram: 1. Magnesium sulfate dissolving tank; 2. Decalcification reaction vessel; 3. Filter press; 4. First cleaning device; 5. Second cleaning device; 6. Dilute magnesium tank; 7. Evaporator; 8. Concentrated magnesium tank; 9. Mixer; 10. Concentration tower; 101. Stripping section; 102. Rectifying section; 11. Centrifugal separation device; 12. Dehydration device; 13. Pyrolysis device; 14. Recovery chamber; 15. Bleaching tower; 16. Cooler; 17. Finished nitric acid storage tank; 18. Condenser; 19. Concentrated nitric acid storage tank; 20. Distribution valve; 21. Dilution tank. Detailed Implementation

[0033] The following will clearly and completely describe the concept, specific structure, and technical effects of this utility model in conjunction with embodiments and accompanying drawings, so as to fully understand the purpose, features, and effects of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are all within the scope of protection of this utility model. Furthermore, all connections / linkages involved in the patent do not simply refer to direct connection of components, but rather to connections that can be made using pipes, conveyor belts, etc., depending on the specific implementation. The various technical features in this utility model can be combined interactively without contradicting each other.

[0034] Reference Figure 1 Embodiment 1 of this utility model provides a calcium-magnesium leaching solution treatment system for by-products of chemical mineral processing, including a leaching solution pretreatment subsystem, a magnesium oxide production subsystem, and a nitric acid recycling subsystem.

[0035] The leaching solution pretreatment subsystem includes a magnesium sulfate dissolving tank 1, a decalcification reaction tank 2, a filter press 3, a first cleaning device 4, a second cleaning device 5, a dilute magnesium tank 6, an evaporator 7, a concentrated magnesium tank 8, a mixer 9, and a concentration tower 10. The concentration tower 10 includes a stripping section 101 and a rectification section 102. The feed end of the rectification section 102 is connected to the top discharge end of the stripping section 101.

[0036] The feed end of the decalcification reaction tank 2 is connected to the discharge end of the magnesium sulfate dissolving tank 1; the feed end of the filter press 3 is connected to the discharge end of the decalcification reaction tank 2; the feed end of the first cleaning device 4 is connected to the solid discharge end of the filter press 3; the feed end of the second cleaning device 5 is connected to the solid discharge end of the first cleaning device 4; the liquid discharge end of the first cleaning device 4 is connected to the feed end of the magnesium sulfate dissolving tank 1; the liquid discharge end of the second cleaning device 5 is connected to the feed end of the first cleaning device 4; the feed end of the dilute magnesium tank 6 is connected to the liquid discharge end of the filter press 3; the feed end of the evaporator 7 is connected to the discharge end of the dilute magnesium tank 6; the feed end of the concentrated magnesium tank 8 is connected to the discharge end of the evaporator 7; the feed end of the mixer 9 is connected to the discharge end of the concentrated magnesium tank 8; and the feed end of the stripping section 101 is connected to the discharge end of the mixer 9.

[0037] It can be understood that the decalcification reaction tank 2 is used to receive calcium-magnesium leaching solution and magnesium sulfate solution. The calcium-magnesium leaching solution and magnesium sulfate solution react in the decalcification reaction tank 2, and then are filtered by the filter press 3 to obtain filter cake and filtrate. The filter cake is mainly calcium sulfate, and the filtrate is mainly decalcification solution containing dilute magnesium nitrate.

[0038] The filter cake is washed twice with water by the first washing device 4 and the second washing device 5 to obtain calcium sulfate product. The washing liquid after washing with water by the first washing device 4 is collected and used to prepare magnesium sulfate solution. The washing liquid after washing with water by the second washing device 5 can be used as the water source for the first washing device 4 when washing the next batch of filter cake, forming a closed loop utilization, reducing water consumption and improving resource utilization.

[0039] The filtrate is discharged into a dilute magnesium tank 6 for subsequent treatment. The dilute magnesium tank 6 is a storage container with a volume of approximately 5-10 cubic meters, made of corrosion-resistant stainless steel or polypropylene, used to temporarily store the decalcified filtrate containing magnesium ions. The decalcified filtrate is then sent from the dilute magnesium tank 6 to an evaporator 7 for evaporation and concentration, yielding a solid-liquid mixture containing 72-76% magnesium nitrate crystals. This solid-liquid mixture is discharged into a concentrated magnesium tank 8 for temporary storage.

[0040] The mixer 9 is used to receive a 60% dilute nitric acid solution and a solid-liquid mixture containing 72-76% magnesium nitrate crystals discharged from the concentrated magnesium tank 8. The 60% dilute nitric acid solution and the solid-liquid mixture containing 72-76% magnesium nitrate crystals react in the mixer 9 at a ratio of 1:3.5. The water of crystallization in the magnesium nitrate crystals interacts with the dilute nitric acid, causing the nitric acid to concentrate and vaporize. At the same time, the concentration of magnesium nitrate crystals decreases, thereby obtaining a solid-liquid mixture of nitric acid vapor with a nitric acid concentration of more than 68.4% and magnesium nitrate crystals of 52-56%. The nitric acid vapor with a concentration of more than 68.4% is further vaporized in the stripping section 101 of the concentration tower 10 to obtain nitric acid vapor with a nitric acid concentration of more than 80%. Then, the nitric acid vapor with a concentration of more than 80% is sent to the rectification section 102. Under the action of reflux acid in the rectification section 102, nitric acid vapor with a nitric acid concentration of more than 98% is obtained.

[0041] The magnesium oxide production subsystem includes a centrifugal separator 11, a dehydration device 12, and a pyrolysis device 13. The feed end of the centrifugal separator 11 is connected to the bottom discharge end of the distillation section 101. The feed end of the dehydration device 12 is connected to the solid discharge end of the centrifugal separator 11. The feed end of the pyrolysis device 13 is connected to the discharge end of the dehydration device 12.

[0042] It can be understood that the solid-liquid mixture of 52-56% magnesium nitrate crystals obtained in the mixer 9 is transported to the concentration tower 10 through a pipeline, and then enters the centrifugal separation device 11 for separation after passing through the bottom of the stripping section 101, to obtain mother liquor and magnesium nitrate crystals. The magnesium nitrate crystals are sent to the dehydration device 12 for dehydration treatment to obtain anhydrous magnesium nitrate. Then, the anhydrous magnesium nitrate is sent to the pyrolysis device 13 for thermal decomposition to obtain magnesium oxide and a gas mixture. The gas mixture mainly contains nitrogen dioxide and oxygen. The gas mixture is sent to the distillation tower for continued recycling reaction, thereby avoiding gas pollution.

[0043] The mother liquor separated in the centrifugal separation device 11 is tested. The mother liquor with a calcium content of less than 0.3% is sent to the dilute magnesium tank 6 for continued circulation reaction, while the mother liquor with a calcium content of more than 0.3% is sent to the decalcification reaction tank 2 for continued decalcification treatment.

[0044] In summary, this invention can effectively separate calcium and magnesium to obtain calcium sulfate and magnesium oxide products, thereby improving the utilization value of the products.

[0045] The nitric acid circulation subsystem includes a bleaching tower 15, a cooler 16, a finished nitric acid storage tank 17, a condenser 18, a concentrated nitric acid storage tank 19, and a distribution valve 20. The feed end of the bleaching tower 15 is connected to the discharge end of the rectification section 102. The feed end of the cooler 16 is connected to the liquid discharge end of the bleaching tower 15. The feed end of the finished nitric acid storage tank 17 is connected to the discharge end of the cooler 16. The feed end of the condenser 18 is connected to the gas discharge end of the bleaching tower 15. The feed end of the concentrated nitric acid storage tank 19 is connected to the discharge end of the condenser 18. The feed end of the distribution valve 20 is connected to the discharge end of the concentrated nitric acid storage tank 19. One discharge end of the distribution valve 20 is connected to the feed end of the rectification section 102, and the other discharge end of the distribution valve 20 is connected to the feed end of the bleaching tower 15.

[0046] Understandably, the nitric acid vapor with a concentration of 98% or higher obtained from the rectification section 102 is transported to the bleaching tower 15 through a pipeline and reacts with the cold nitric acid liquid added to the bleaching tower 15 to obtain hot nitric acid liquid and nitric acid vapor. The hot nitric acid liquid is cooled by the cooler 16 to obtain finished nitric acid. The finished nitric acid is discharged to the finished nitric acid storage tank 17 for storage. The nitric acid vapor discharged from the top of the bleaching tower 15 is transported to the condenser 18 through a pipeline for condensation. After condensation, concentrated nitric acid is obtained and discharged to the concentrated nitric acid storage tank 19 for storage.

[0047] Furthermore, the concentrated nitric acid in the concentrated nitric acid storage tank 19 is proportioned via the distribution valve 20. One-third of the concentrated nitric acid is returned to the bleaching tower 15 through a pipeline, serving as cold nitric acid liquid in contact with nitric acid vapor, thus achieving nitric acid recycling. This reduces the amount of cold nitric acid liquid added to the bleaching tower 15 and increases the production yield of finished nitric acid. The remaining two-thirds of the concentrated nitric acid is returned to the rectification section 102 through a pipeline as reflux acid, further reducing the amount of reflux acid added to the subsequent rectification section 102 and achieving nitric acid recycling.

[0048] In summary, this invention enables the recycling and recovery of nitric acid, reducing production costs and pollution emissions.

[0049] Reference Figure 2Embodiment 2 of this utility model provides a system for treating calcium-magnesium leaching solution, a byproduct of chemical mineral processing. The difference from Embodiment 1 is that the magnesium oxide production subsystem further includes a recovery chamber 14. The gas outlet of the pyrolysis device 13 is connected to the feed inlet of the recovery chamber 14. The recovery chamber 14 is equipped with nozzles to spray water. The gas (nitrogen dioxide and oxygen) generated by the pyrolysis device 13 reacts with water to obtain 18% dilute nitric acid. This 18% dilute nitric acid can be recycled in production processes, such as phosphate rock leaching. This avoids pollution from gas emissions, recovers and reuses the gas, and improves resource utilization.

[0050] Reference Figure 3 Embodiment 3 of this utility model provides a treatment system for calcium-magnesium leaching solution, a byproduct of chemical mineral processing. The difference from Embodiment 1 is that the nitric acid circulation subsystem further includes a dilution tank 21. The concentrated nitric acid in the concentrated nitric acid storage tank 19 is discharged to the dilution tank 21. The concentrated nitric acid is diluted to 60% dilute nitric acid in the dilution tank 21 before being sent to the mixer 9. This can reduce the amount of 60% dilute nitric acid added to the mixer 9, thereby realizing the circulation of nitric acid and reducing production costs.

[0051] The above is a detailed description of the preferred embodiments of the present utility model. However, the present utility model is not limited to the described embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present utility model. All such equivalent modifications or substitutions are included within the scope defined by the claims of this application.

Claims

1. A system for treating calcium- and magnesium-containing leaching solutions as byproducts of chemical mineral processing, characterized in that: The system includes a leaching solution pretreatment subsystem, a magnesium oxide production subsystem, and a nitric acid circulation subsystem. The leaching solution pretreatment subsystem comprises a decalcification reaction tank, a filter press, an evaporator, a mixer, and a concentration tower connected in sequence. The concentration tower includes a stripping section and a rectification section, with the feed end of the rectification section connected to the top discharge end of the stripping section. The magnesium oxide production subsystem includes a centrifugal separator, a dehydration device, and a pyrolysis device connected in sequence, with the feed end of the centrifugal separator connected to the bottom discharge end of the stripping section. The nitric acid circulation subsystem includes a bleaching tower, a cooler, a finished nitric acid storage tank, and a condenser. The feed end of the bleaching tower is connected to the discharge end of the rectification section. The feed ends of the cooler and condenser are respectively connected to the liquid discharge end and gas discharge end of the bleaching tower. The feed end of the finished nitric acid storage tank is connected to the discharge end of the cooler.

2. The system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 1, characterized in that: The leaching solution pretreatment subsystem also includes a magnesium sulfate dissolving tank, and the feed end of the decalcification reaction tank is connected to the discharge end of the magnesium sulfate dissolving tank.

3. The system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 2, characterized in that: The leaching solution pretreatment subsystem further includes a first cleaning device and a second cleaning device. The feed end of the first cleaning device is connected to the solid discharge end of the filter press, the feed end of the second cleaning device is connected to the solid discharge end of the first cleaning device, the liquid discharge end of the first cleaning device is connected to the feed end of the magnesium sulfate dissolving tank, and the liquid discharge end of the second cleaning device is connected to the feed end of the first cleaning device.

4. The system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 3, characterized in that: The leachate pretreatment subsystem also includes a dilute magnesium tank, the feed end of which is connected to the liquid discharge end of the filter press, and the discharge end of which is connected to the feed end of the evaporator.

5. A system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 4, characterized in that: The discharge end of the centrifugal separator is connected to the feed end of the magnesium sulfate dissolving tank and the dilute magnesium tank.

6. The system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 1, characterized in that: The leaching solution pretreatment subsystem also includes a magnesium concentration tank, the feed end of which is connected to the discharge end of the evaporator, and the discharge end of which is connected to the feed end of the mixer.

7. A system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 1, characterized in that: The gas outlet of the pyrolysis device is connected to the feed inlet of the rectification section.

8. A system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 1, characterized in that: The gas outlet of the pyrolysis device is connected to a recovery chamber, which is used to recover the gas generated by the pyrolysis device.

9. A system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 1, characterized in that: The nitric acid circulation subsystem also includes a distribution valve, the discharge end of the condenser is connected to the distribution valve, and the feed end of the rectification section and the feed end of the bleaching tower are respectively connected to the two discharge ends of the distribution valve.

10. A system for treating calcium- and magnesium-containing leaching solutions as a byproduct of chemical mineral processing according to claim 1, characterized in that: The nitric acid circulation subsystem also includes a dilution tank, with the discharge end of the condenser connected to the inlet end of the dilution tank, and the discharge end of the dilution tank connected to the inlet end of the mixer.

Images