A system for removing impurity metal ions from a sodium pyrophosphate crude product
By treating crude sodium pyrophosphate with hydrogen peroxide and a composite settling agent in a dissolving vessel, combined with pH adjustment and centrifugal separation, the problems of poor quality and high cost of crude sodium pyrophosphate recovery products were solved, and high-purity sodium pyrophosphate was prepared.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- FUHUA TONGDA CHEM CO LTD
- Filing Date
- 2025-06-30
- Publication Date
- 2026-07-31
AI Technical Summary
There are few existing technologies for utilizing crude sodium pyrophosphate, and the quality of the recovered products is poor and the cost is high, resulting in low value and making it difficult to promote and apply in industry.
The crude sodium pyrophosphate is imported into a dissolving vessel and oxidized by hydrogen peroxide to remove low-valence iron and manganese ions to high-valence states. A composite settling agent, such as ethylenediaminetetraacetic acid and dimercaprol, is used to bind the heavy metal ions. A pH adjuster is also used to remove the precipitate. High-purity sodium pyrophosphate is obtained through crystallization and centrifugation.
The preparation of high-purity sodium pyrophosphate has been achieved, reducing production costs and improving product quality and economic efficiency.
Smart Images
Figure CN224578041U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of crude sodium pyrophosphate refining technology, specifically relating to a system for removing impurity metal ions from crude sodium pyrophosphate. Background Technology
[0002] With the Ministry of Industry and Information Technology's Announcement No. 1158 explicitly prohibiting the sale of glyphosate aqueous solutions with an effective ingredient content of less than 30%, more than 1.5 million tons / year of high-concentration glyphosate wastewater in China cannot be sold as a commodity (containing more than 35,000 tons / year of phosphorus). The common practice of glyphosate manufacturers is to incinerate the wastewater, where the organic components are pyrolyzed, and a crude pyrophosphate byproduct with a content of about 80% is obtained. Crude sodium pyrophosphate contains a large amount of heavy metals and cannot be used directly.
[0003] Currently, there are few technologies for utilizing crude sodium pyrophosphate, and the existing technologies for utilizing crude sodium pyrophosphate produce poor-quality recycled products, which are all industrial-grade products (such as patents CN106809812A and CN106335889A). Therefore, the product value is very low. In addition, the recycling methods themselves are costly. As a result, these recycling solutions are not economical or practical, making it difficult to promote and apply them in industry and failing to solve the technical problem of the difficulty in recycling large quantities of crude sodium pyrophosphate.
[0004] Chinese patent CN111646448A, published on September 11, 2020, discloses a method for preparing food-grade sodium pyrophosphate from glyphosate byproduct crude sodium pyrophosphate, comprising the following steps: S1, dissolving crude sodium pyrophosphate in water at a volume ratio of 1:3 to 5 at 80–90°C under stirring, controlling the system temperature at 70–95°C, reacting for 30–60 minutes, and then allowing the mixture to stand at this temperature for 10–30 minutes after the reaction is complete to obtain a first reaction solution; S2, filtering to remove insoluble mechanical impurities from the first reaction solution. The mixture is purified to obtain a clear liquid. Then, 0.1–1% hydrogen peroxide (by mass) is added to the clear liquid until the pH reaches 8–9, at which point the addition of hydrogen peroxide is stopped. Next, K₂S or Na₂S is added, with a mass ratio of K₂S to the clear liquid of 0.05–0.1:100. The system temperature is then raised to 70–95°C and stirred at 20–30 r / min for 5–20 min. Finally, polyaluminum chloride (PAC) is added, with a mass ratio of PAC to the clear liquid of 0.05–0.1:100. After thorough dispersion, let stand for 10-30 minutes to obtain the second reaction solution; S3, filter the second reaction solution to obtain the filtrate, evaporate and concentrate the filtrate, evaporating 30-60% of the total mass of the second reaction solution to obtain the concentrate, then cool the concentrate with chilled water at 0-5°C. After the first crystallization occurs, separate the first crystallization, and the residual liquid phase is the first mother liquor; S4, mix the first crystallization with deionized water at 80-90°C at a volume ratio of 1:3-5. The solution is dissolved under stirring, with the system temperature controlled at 70–95°C, and reacted for 30–60 minutes. After the reaction is complete, it is kept at this temperature and allowed to stand for 10–30 minutes to obtain the third reaction solution. The third reaction solution is then cooled with chilled water at 0–5°C until a second crystal is formed. The second crystal is then separated, and the residual liquid phase is the second mother liquor. S5. The second crystal is heated to 350–400°C for 60–100 minutes to obtain the heated product. The heated product is then ground to obtain sodium pyrophosphate. This patent uses hydrogen peroxide + K2S or Na2S + polyaluminum chloride to remove heavy metals and organic impurities; however, the sodium pyrophosphate prepared by this patent has the disadvantages of low purity and high production cost. Utility Model Content
[0005] The purpose of this invention is to solve the problems of the prior art and provide a system for removing impurity metal ions from crude sodium pyrophosphate. Crude sodium pyrophosphate is added to a dissolving vessel through a crude sodium pyrophosphate inlet, followed by demineralized water added to the dissolving vessel through an inlet pipe. The crude sodium pyrophosphate dissolves to obtain a sodium pyrophosphate solution. Hydrogen peroxide is then added through a hydrogen peroxide inlet pipe to oxidize the low-valence iron and manganese ions in the sodium pyrophosphate solution to high-valence states. Finally, a composite settling agent (comprising ethylenediaminetetraacetic acid and dimercaprol) is added through a composite settling agent inlet pipe. Ethylenediaminetetraacetic acid (EDTA) exhibits high selectivity and strong chelating ability for oxidized high-valence iron, manganese, and lead ions. Dimercaprol effectively binds mercury ions. A pH adjuster is added through the pH inlet pipe, and the solution flows into the filter through the feed pipe, achieving efficient removal of various heavy metal impurities. The solution used to remove the precipitate flows into a crystallizer, where crystallization occurs. The crystals are then separated by centrifugation to obtain sodium pyrophosphate crystals. The sodium pyrophosphate crystals are washed three times with a small amount of deionized water and dried in an oven to obtain a high-purity sodium pyrophosphate product. This invention can produce a high-purity sodium pyrophosphate product.
[0006] This utility model is achieved through the following technical solution:
[0007] A system for removing impurity metal ions from crude sodium pyrophosphate includes a dissolving vessel, which is equipped with a water inlet pipe, a crude sodium pyrophosphate inlet, a hydrogen peroxide inlet pipe, a composite flocculant inlet pipe, a pH adjuster inlet pipe, and a discharge pipe. The discharge pipe is connected to a filter, the filter is connected to a crystallizer via a connecting pipe, the crystallizer is connected to a centrifugal separator, and the centrifugal separator is connected to an oven.
[0008] Preferably, the dissolving vessel is provided with a temperature control unit, which includes a temperature sensor and a heat exchange jacket. The heat exchange jacket is provided with a heat exchange inlet pipe and a heat exchange outlet pipe, and a heat exchange valve is provided on the heat exchange inlet pipe.
[0009] Preferably, the dissolving vessel is equipped with a stirring device.
[0010] Preferably, the dissolving vessel is equipped with a pH meter.
[0011] Preferably, the filter is a plate and frame filter.
[0012] Preferably, the water inlet pipe, hydrogen peroxide inlet pipe, composite flocculant inlet pipe, pH adjuster inlet pipe, and discharge pipe are all equipped with on / off valves.
[0013] Preferably, flow meters are installed on the water inlet pipe, hydrogen peroxide inlet pipe, composite flocculant inlet pipe, and pH adjuster inlet pipe.
[0014] Compared with the prior art, this utility model has the following advantages and beneficial effects:
[0015] I. This utility model provides a system for removing impurity metal ions from crude sodium pyrophosphate. The crude sodium pyrophosphate is added to a dissolving vessel through a crude sodium pyrophosphate inlet. Subsequently, demineralized water is added to the dissolving vessel through an inlet pipe. The crude sodium pyrophosphate dissolves to obtain a sodium pyrophosphate solution. Then, hydrogen peroxide is added through a hydrogen peroxide inlet pipe to oxidize the low-valence iron and manganese ions in the sodium pyrophosphate solution to high-valence ions. Next, a composite settling agent (comprising ethylenediaminetetraacetic acid and dimercaprol) is added through a composite settling agent inlet pipe. The acid exhibits high selectivity and strong chelating ability for oxidized high-valence iron, manganese, and lead ions. Dimercaprol can effectively bind mercury ions. A pH adjuster is added through the pH adjuster inlet pipe, and the solution flows into the filter through the feed pipe, achieving efficient removal of various heavy metal impurities. The solution used to remove the precipitate flows into a crystallizer, where crystallization occurs. The crystals are then separated by centrifugation to obtain sodium pyrophosphate crystals. The sodium pyrophosphate crystals are washed three times with a small amount of deionized water and dried in an oven to obtain a high-purity sodium pyrophosphate product. This invention can produce a high-purity sodium pyrophosphate product.
[0016] II. The present invention provides a system for removing impurity metal ions from crude sodium pyrophosphate. The temperature control unit facilitates the adjustment of the temperature inside the dissolving vessel, resulting in more thorough dissolution of crude sodium pyrophosphate and better precipitation of metal impurities.
[0017] III. The present invention provides a system for removing impurity metal ions from crude sodium pyrophosphate. The pH meter and the pH adjuster inlet pipe facilitate the adjustment of the pH value in the dissolving vessel.
[0018] IV. The present invention provides a system for removing impurity metal ions from crude sodium pyrophosphate, with the addition of a switching valve and a flow meter for convenient feeding and unloading. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the structure of this utility model;
[0020] Figure 2 This is a schematic diagram of the structure of Embodiment 2 of this utility model.
[0021] The components include: 1. Dissolving vessel; 2. Hydrogen peroxide inlet pipe; 3. Composite flocculant inlet pipe; 4. pH adjuster inlet pipe; 5. Feed pipe; 6. Filter; 7. Connecting pipe; 8. Crystallizer; 9. Centrifugal separator; 10. Oven; 11. Temperature sensor; 12. Heat exchange jacket; 13. Heat exchange inlet pipe; 14. Heat exchange outlet pipe; 15. Heat exchange valve; 16. Stirring device; 17. pH meter; 18. Switch valve; 19. Flow meter; 20. Sodium pyrophosphate crude product inlet; 21. Water inlet pipe. Detailed Implementation
[0022] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.
[0023] Example 1
[0024] like Figure 1 As shown, this embodiment provides a system for removing impurity metal ions from crude sodium pyrophosphate, including a dissolving vessel 1. The dissolving vessel 1 is equipped with a water inlet pipe 21, a crude sodium pyrophosphate inlet 20, a hydrogen peroxide inlet pipe 2, a composite flocculant inlet pipe 3, a pH adjuster inlet pipe 4, and a feed pipe 5. The feed pipe 5 is connected to a filter 6. The filter 6 is connected to a crystallizer 8 through a connecting pipe 7. The crystallizer 8 is connected to a centrifugal separator 9. The centrifugal separator 9 is connected to an oven 10.
[0025] Example 2
[0026] A system for removing impurity metal ions from crude sodium pyrophosphate includes a dissolving vessel 1. The dissolving vessel 1 is equipped with a water inlet pipe 21, a crude sodium pyrophosphate inlet 20, a hydrogen peroxide inlet pipe 2, a composite flocculant inlet pipe 3, a pH adjuster inlet pipe 4, and a feed pipe 5. The feed pipe 5 is connected to a filter 6. The filter 6 is connected to a crystallizer 8 via a connecting pipe 7. The crystallizer 8 is connected to a centrifugal separator 9. The centrifugal separator 9 is connected to an oven 10.
[0027] The melting vessel 1 is equipped with a temperature control unit, which includes a temperature sensor 11 and a heat exchange jacket 12. The heat exchange jacket 12 is equipped with a heat exchange inlet pipe 13 and a heat exchange outlet pipe 14, and a heat exchange valve 15 is equipped with the heat exchange inlet pipe 13.
[0028] The dissolving vessel 1 is equipped with a stirring device 16.
[0029] A pH meter 17 is installed on the dissolving vessel 1.
[0030] The filter 6 is a plate and frame filter.
[0031] The water inlet pipe 21, hydrogen peroxide inlet pipe 2, composite flocculant inlet pipe 3, pH adjuster inlet pipe 4, and discharge pipe 5 are all equipped with switch valves 18.
[0032] Flow meters 19 are installed on the water inlet pipe 21, hydrogen peroxide inlet pipe 2, composite flocculant inlet pipe 3 and pH adjuster inlet pipe 4.
[0033] Among them, temperature sensor 11, heat exchange valve 15, stirring device 16, pH meter 17, switching valve 18 and flow meter 19 are all existing technologies and will not be described in detail here.
[0034] Compared with the prior art, this utility model has the following advantages and beneficial effects:
[0035] I. This utility model provides a system for removing impurity metal ions from crude sodium pyrophosphate. The crude sodium pyrophosphate is added to a dissolving vessel 1 through the crude sodium pyrophosphate inlet 20. Subsequently, demineralized water is added to the dissolving vessel 1 through the water inlet pipe 21. The crude sodium pyrophosphate dissolves to obtain a sodium pyrophosphate solution. Then, hydrogen peroxide is added through the hydrogen peroxide inlet pipe 2 to oxidize the low-valence iron and manganese ions in the sodium pyrophosphate solution to high-valence ions. Next, a composite settling agent (comprising ethylenediaminetetraacetic acid and dimercaprol) is added through the composite settling agent inlet pipe 3. The acid exhibits high selectivity and strong chelating ability for oxidized high-valence iron, manganese, and lead ions. Dimercaprol can effectively bind mercury ions. A pH adjuster is added through the pH adjuster inlet pipe 4, and the solution flows into the filter 6 through the feed pipe 5, achieving efficient removal of various heavy metal impurities. The solution used to remove the precipitate flows into the crystallizer 8, where crystallization is performed. The crystals are then separated by centrifugation using the centrifuge separation device 9 to obtain sodium pyrophosphate crystals. The sodium pyrophosphate crystals are washed three times with a small amount of deionized water and dried in the oven 10 to obtain a high-purity sodium pyrophosphate product. This invention can obtain a high-purity sodium pyrophosphate product.
[0036] II. The present invention provides a system for removing impurity metal ions from crude sodium pyrophosphate. The temperature control unit facilitates the adjustment of the temperature inside the dissolving vessel 1, resulting in more thorough dissolution of crude sodium pyrophosphate and better precipitation of metal impurities.
[0037] III. The present invention provides a system for removing impurity metal ions from crude sodium pyrophosphate. The pH meter 17 and the pH adjuster inlet pipe 4 facilitate the adjustment of the pH value in the dissolving vessel 1.
[0038] IV. The present invention provides a system for removing impurity metal ions from crude sodium pyrophosphate. The setting of the switching valve 18 and the flow meter 19 facilitates material feeding and unloading.
[0039] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present utility model shall fall within the protection scope of the present utility model.
Claims
1. A system for removing impurity metal ions from a crude sodium pyrophosphate, characterized by: The equipment includes a dissolving vessel (1), which is equipped with a water inlet pipe (21), a crude sodium pyrophosphate inlet (20), a hydrogen peroxide inlet pipe (2), a composite precipitant inlet pipe (3), a pH adjuster inlet pipe (4), and a feed pipe (5). The feed pipe (5) is connected to a filter (6), which is connected to a crystallizer (8) via a connecting pipe (7). The crystallizer (8) is connected to a centrifugal separator (9), which is connected to an oven (10).
2. The system for removing impurity metal ions from sodium pyrophosphate crude product according to claim 1, characterized in that: The melting vessel (1) is equipped with a temperature control unit, which includes a temperature sensor (11) on the melting vessel (1) and a heat exchange jacket (12) on the melting vessel (1). The heat exchange jacket (12) is equipped with a heat exchange inlet pipe (13) and a heat exchange outlet pipe (14). The heat exchange inlet pipe (13) is equipped with a heat exchange valve (15).
3. The system for removing impurity metal ions from sodium pyrophosphate crude product according to claim 1, characterized in that: The dissolving vessel (1) is equipped with a stirring device (16).
4. The system for removing impurity metal ions from sodium pyrophosphate crude product according to claim 1, characterized in that: A pH meter (17) is installed on the dissolving vessel (1).
5. The system for removing impurity metal ions from crude sodium pyrophosphate according to claim 1, characterized in that: The filter (6) is a plate and frame filter.
6. The system for removing impurity metal ions from crude sodium pyrophosphate according to claim 1, characterized in that: The water inlet pipe (21), hydrogen peroxide inlet pipe (2), composite flocculant inlet pipe (3), pH adjuster inlet pipe (4) and discharge pipe (5) are all equipped with switch valves (18).
7. The system for removing impurity metal ions from crude sodium pyrophosphate according to claim 1, characterized in that: Flow meters (19) are installed on the water inlet pipe (21), hydrogen peroxide inlet pipe (2), composite flocculant inlet pipe (3) and pH adjuster inlet pipe (4).