Phosphate plant dam backwater neutralization system
Patent Information
- Application Number
- CN202522308006.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-10-23
- Estimated Expiration
- 2035-10-31
AI Technical Summary
[0003]如果直接循环利用上述渣场回水至生产系统，氟离子与磷酸盐会在循环系统内持续富集，若后续处理不及时，存在环保处罚风险；强酸性回水若密封不当或发生泄漏，会对土壤、地下水造成酸化污染；而且强酸性回水会对生产设备造成腐蚀，缩短设备使用寿命；另外，回水直接回用会损失五氧化二磷和氟资源
[0010]本实用新型的优点：利用一部分回水用于调制石灰乳，并通过石灰乳来中和回水母管返回的回水，石灰乳中的氢氧化钙与回水中的酸性物质发生中和反应，提高回水PH值，氢氧化钙与磷酸反应生成磷酸钙，氢氧化钙与氟离子反应生成氟化钙沉淀，氢氧化钙与硫酸根反应生成硫酸钙沉淀；沉淀物通过污泥泵输送至反应槽，富集有磷和氟的沉淀物可作为原料，返回磷酸装置进行再利用；而分离出的清液可用作磷酸厂、磷肥厂生产设备的冷却水，拓展水利用途径。
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Figure CN224883882U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of phosphoric acid production wastewater treatment technology, and in particular to a phosphoric acid plant slag dam wastewater neutralization treatment system. Background Technology
[0002] The source of the slag dam return water in the phosphate plant is the phosphogypsum slag produced by the reaction of phosphate rock and sulfuric acid in the wet process of phosphate production. It is transported to the slag yard for storage through the wet slag discharge system and enters the process drainage of the slag yard along with the slag body, as well as the collected rainwater. The slag yard return water is a strongly acidic industrial wastewater with a pH value of 2-3. It also contains a small amount of sulfate. According to the test, it contains about 0.6% phosphorus pentoxide and about 500 ppm fluorine.
[0003] If the wastewater from the slag heap is directly recycled back to the production system, fluoride ions and phosphates will continue to accumulate in the recycling system. If subsequent treatment is not timely, there is a risk of environmental penalties. If the highly acidic wastewater is not properly sealed or leaks, it will cause acidification pollution to the soil and groundwater. Moreover, the highly acidic wastewater will corrode the production equipment and shorten its service life. In addition, direct reuse of the wastewater will result in the loss of phosphorus pentoxide and fluorine resources.
[0004] Therefore, how to effectively treat and reuse this wastewater has become an urgent problem to be solved. Utility Model Content
[0005] The purpose of this invention is to provide a neutralization treatment system for phosphate plant slag dam return water, which neutralizes the return water from the slag yard, reduces the content of phosphorus, fluoride, sulfate and other elements in the return water, increases the pH value, and makes the treated return water neutral for efficient reuse.
[0006] This utility model is implemented by the following technical solution: a phosphate plant slag dam return water neutralization treatment system, which includes a return water main pipe, a quicklime tank, a lime slurry mixing tank, a neutralization tank, and a thickener; a belt scale is installed below the discharge port of the quicklime tank, and the unloading end of the belt scale is placed above the lime slurry mixing tank; the return water main pipe is connected to the lime slurry mixing tank, and a mixer is installed in the lime slurry mixing tank; the lime slurry mixing tank is connected to the neutralization tank through a feed pump, and the neutralization tank is connected to the return water main pipe through a return water branch pipe; the neutralization tank is connected to the thickener through a neutralization return water conveying pump, the bottom of the thickener is connected to the reaction tank through an underflow pump, the upper overflow tank of the thickener is connected to the return water buffer tank through an overflow pipe, and the return water buffer tank is connected to the return water return pump.
[0007] Furthermore, the return water main pipe is connected to the lime slurry mixing tank through a mixing branch pipe, and a manual valve, a regulating valve, and a flow meter are installed on the mixing branch pipe.
[0008] Furthermore, a butterfly valve and a flow meter are installed on the return water branch pipe.
[0009] Furthermore, a level gauge is installed inside the thickener, and the level gauge is electrically connected to the return water transfer pump via a DCS.
[0010] The advantages of this invention are as follows: A portion of the recycled water is used to prepare lime slurry, which neutralizes the recycled water returning from the main pipe. The calcium hydroxide in the lime slurry neutralizes the acidic substances in the recycled water, increasing the pH value. Calcium hydroxide reacts with phosphoric acid to form calcium phosphate, calcium hydroxide reacts with fluoride ions to form calcium fluoride precipitate, and calcium hydroxide reacts with sulfate ions to form calcium sulfate precipitate. The precipitate is transported to the reaction tank by a sludge pump. The precipitate enriched with phosphorus and fluoride can be used as raw material and returned to the phosphoric acid unit for reuse. The separated clear liquid can be used as cooling water for the production equipment of phosphoric acid plants and phosphate fertilizer plants, expanding the ways of water utilization. Attached Figure Description
[0011] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0012] Figure 1 This is a schematic diagram of the structure of this utility model.
[0013] The components in the attached diagram are labeled as follows: 1. Quicklime silage tank; 2. Belt scale; 3. Lime slurry mixing tank; 4. Return water main pipe; 5. Feed pump; 6. Neutralization tank; 7. Return water branch pipe; 8. Neutralization return water conveying pump; 9. Thickener; 10. Underflow pump; 11. Reaction tank; 12. Overflow pipe; 13. Return water buffer tank; 14. Return water return pump; 15. Mixing branch pipe; 16. Manual valve; 17. Regulating valve; 18. Butterfly valve; 19. Level gauge. Detailed Implementation
[0014] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0015] like Figure 1 As shown in the figure, this embodiment provides a phosphate plant slag dam return water neutralization treatment system, which includes a return water header 4, a quicklime tank 1, a lime slurry mixing tank 3, a neutralization tank 6, and a thickener 9.
[0016] A belt scale 2 is installed below the outlet of the quicklime silage tank 1, and the unloading end of the belt scale 2 is positioned above the lime slurry mixing tank 3. According to the process requirements, a certain amount of quicklime is transported to the lime slurry mixing tank 3 using the belt scale 2. The return water main pipe 4 is connected to the lime slurry mixing tank 3 through the mixing branch pipe 15. A mixer is installed in the lime slurry mixing tank 3, and a manual valve 16, a regulating valve 17, and a flow meter are installed on the mixing branch pipe 15. The return water is sent into the lime slurry mixing tank 3 through the mixing branch pipe 15 and mixed with the quicklime to form a lime slurry solution. The flow rate of the returned water is detected in real time by the flow meter, and the signal is fed back to the DCS in real time. The DCS controls the opening of the regulating valve 17, thereby adjusting the amount of return water sent into the lime slurry mixing tank 3. Thus, a portion of the return water is used to prepare the lime slurry.
[0017] The lime slurry mixing tank 3 is connected to the neutralization tank 6 via the feed pump 5. The neutralization tank 6 is connected to the return water main pipe 4 via the return water branch pipe 7. A mixer is installed inside the neutralization tank 6. The prepared lime slurry solution is transported to the neutralization tank 6 by the feed pump 5. Under the action of stirring, it undergoes a neutralization reaction with a large amount of return water sent in by the return water branch pipe 7. A butterfly valve 18 and a flow meter are installed on the return water branch pipe 7. The flow meter detects the return water flow rate sent into the neutralization tank 6 in real time and feeds the signal back to the DCS in real time.
[0018] The calcium hydroxide in lime slurry neutralizes the acidic substances in the return water, increasing the pH value of the return water. Calcium hydroxide reacts with phosphoric acid to form calcium phosphate, calcium hydroxide reacts with fluoride ions to form calcium fluoride precipitate, and calcium hydroxide reacts with sulfate ions to form calcium sulfate precipitate.
[0019] Neutralization tank 6 is connected to thickener 9 via neutralization return water pump 8. The bottom of thickener 9 is connected to reaction tank 11 via underflow pump 10. The upper overflow tank of thickener 9 is connected to return water buffer tank 13 via overflow pipe 12. Return water buffer tank 13 is connected to return water header 4 via return water return pump 14. The mixed liquid after neutralization reaction is sent to thickener 9 via neutralization return water pump 8. Utilizing the principle of gravity sedimentation, the generated calcium phosphate, calcium fluoride, calcium sulfate and other precipitate particles sink to the bottom to form sludge sediment. Part of the sediment is transported to reaction tank 11 via sludge pump. The sediment enriched with phosphorus and fluorine can be used as raw material and returned to the phosphoric acid unit for reuse. The upper part is the clarified liquid, which is returned to return water buffer tank 13 via overflow tank and overflow pipe 12, and then sent back to the next filtration process via return water return pump 14. The separated clear liquid can be used as cooling water for production equipment in phosphoric acid plants and phosphate fertilizer plants, expanding the water utilization pathways.
[0020] A level gauge 19 is installed inside the thickener 9. The level gauge 19 is electrically connected to the return water transfer pump through the DCS. The level gauge 19 monitors the liquid level inside the thickener 9 in real time and feeds the signal back to the DCS, thereby controlling the start and stop of the return water transfer pump.
[0021] 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 phosphate plant slag dam backwater neutralization treatment system, characterized in that, It includes a return water header, quicklime silage tank, lime slurry mixing tank, neutralization tank, and thickener; A belt scale is installed below the discharge port of the quicklime silage tank, and the unloading end of the belt scale is positioned above the lime slurry mixing tank; the return water header is connected to the lime slurry mixing tank, and a mixer is installed inside the lime slurry mixing tank; The lime slurry mixing tank is connected to the neutralization tank via a feed pump, and the neutralization tank is connected to the return water main pipe via a return water branch pipe. The neutralization tank is connected to the thickener via a neutralization return water pump. The bottom of the thickener is connected to the reaction tank via a bottom flow pump. The upper overflow tank of the thickener is connected to the return water buffer tank via an overflow pipe. The return water buffer tank is connected to the return water return pump.
2. The phosphate plant slag dam backwater neutralization treatment system according to claim 1, characterized in that, The return water main pipe is connected to the lime slurry mixing tank through the mixing branch pipe, and the mixing branch pipe is equipped with a manual valve, a regulating valve, and a flow meter.
3. The phosphate plant slag dam backwater neutralization treatment system according to claim 1, characterized in that, A butterfly valve and a flow meter are installed on the return water branch pipe.
4. The phosphate plant slag dam backwater neutralization treatment system according to claim 3, characterized in that, The thickener is equipped with a level gauge, which is electrically connected to the return water pump via a DCS.