Method for improving yield of urea phosphate prepared from wet-process phosphoric acid
By adding a crystallizer during the wet-process phosphoric acid preparation of urea phosphate and controlling the reaction and crystallization conditions, the problem of low yield of wet-process phosphoric acid was solved, and the yield of urea phosphate was significantly improved and the mother liquor was reduced, producing crystalline urea phosphate particles that meet industrial standards.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- WENGFU (GRP) CO LTD
- Filing Date
- 2024-04-16
- Publication Date
- 2026-06-09
AI Technical Summary
The wet process for preparing urea phosphate from phosphoric acid has a low yield, produces a large amount of mother liquor, and is difficult to utilize at high value. Existing technologies have failed to effectively improve the yield.
The yield of urea phosphate can be improved by mixing crystallizers such as ethylene glycol methyl ether, ethylenediaminetetraacetic acid, or citric acid with wet-process phosphoric acid and urea, and by controlling the reaction conditions and crystallization process.
It significantly increases the yield of urea phosphate by 5-15%, reduces the production of mother liquor, and produces urea phosphate in the form of crystalline particles that meet industrial standards. It is low in cost and easy to industrialize.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of fine chemical production technology, specifically relating to a method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation. Background Technology
[0002] Urea phosphate (UP), with the molecular formula CO(NH2)2·H3PO4, is a colorless, transparent prismatic crystal that is readily soluble in water. Urea phosphate is widely used in industrial, agricultural, and livestock sectors. Thermal phosphoric acid production is costly; therefore, wet phosphoric acid production is the primary method for urea phosphate production. However, the yield of urea phosphate produced by the wet phosphoric acid process is low, only around 40-50% industrially, and it generates a large volume of mother liquor with high nutrient content that cannot be utilized for high-value purposes.
[0003] Liu Xiao (Research on the Process of Preparing Industrial-Grade Urea Phosphate from Wet-Process Phosphoric Acid) used purified phosphoric acid (wet-process phosphoric acid purified from phthalic acid) as raw material, which increased the yield of urea phosphate by 2.6%. Zhang Chuntao et al. proposed a method for producing urea phosphate by wet-process phosphoric acid dissolution coupled with cooling crystallization. This method is complex, requires the addition of a large amount of acetone, and the resulting urea phosphate mother liquor and acetone are difficult to separate.
[0004] However, there are currently no reports on technologies for improving the yield of urea phosphate in the wet process of phosphoric acid production. Based on this, this application was developed. Summary of the Invention
[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation. This method improves the yield of urea phosphate by using a crystallizer to reduce the solubility of urea phosphate.
[0006] To achieve the above objectives, the present invention adopts the following technical solution:
[0007] A method for improving the yield of urea phosphate in the preparation of wet-process phosphoric acid involves mixing a crystallizer with wet-process phosphoric acid and urea, reacting the mixture, and then cooling, crystallizing, filtering, and drying to obtain urea phosphate after the reaction is complete.
[0008] Alternatively, wet-process phosphoric acid can be mixed with urea and reacted. After the reaction is complete, a crystallizer or a mother liquor containing a crystallizer is added, and urea phosphate is obtained by cooling, crystallizing, filtering, and drying.
[0009] Specifically, the crystallizing agent is one or a mixture of two or more of ethylene glycol methyl ether, ethylenediaminetetraacetic acid, and citric acid in any proportion.
[0010] Specifically, the amount of crystallizer added can be 0.01%-5% of the sum of the mass of wet-process phosphoric acid and urea, or the sum of the mass of wet-process phosphoric acid, urea, and urea phosphate mother liquor. More preferably, the amount of crystallizer added is 0.1%-3%. The amount of urea added is 90%-110% of the theoretical reaction amount with wet-process phosphoric acid.
[0011] Furthermore, in the method for increasing the yield of urea phosphate, it is preferable to react at 50-90°C for 1-3 hours.
[0012] Specifically, when urea phosphate mother liquor containing a crystallizer is added, the system is concentrated and then cooled for crystallization.
[0013] Furthermore, the wet-process phosphoric acid (H3PO4) contains 20%-70% P2O5 by mass. That is, the wet-process phosphoric acid is wet-process phosphoric acid with a P2O5 mass fraction of 20%-70%, preferably wet-process phosphoric acid with a P2O5 mass fraction of 30%-60%, and can be directly purchased from ordinary commercial products.
[0014] The reaction formula for the preparation of urea phosphate from wet-process phosphoric acid and urea is as follows:
[0015] H3PO4+ CO(NH2)2= CO(NH2)2·H3PO4
[0016] Compared with existing technologies, the method of the present invention has the following advantages:
[0017] 1) The crystallizer used in this invention can improve the yield of urea phosphate prepared by wet phosphoric acid, and the yield of urea phosphate can be increased by about 5-15%, which meets the market requirements for urea phosphate.
[0018] 2) The crystallizer added in this invention helps to reduce the amount of urea phosphate mother liquor produced;
[0019] 3) The crystallizer selected in this invention requires a small amount, is low in cost, and is easy to add, which facilitates the industrial production of urea phosphate;
[0020] 4) The urea phosphate produced by the method of this invention is in the form of crystalline particles (particle size 0.1-0.5 mm). The produced urea phosphate meets the industrial urea phosphate standard (GB / T27805-2011), can meet market demand, has low crystallization agent cost, flexible addition method, and is very convenient for actual production;
[0021] The urea phosphate produced by the method of this invention is in the form of crystalline particles, meeting the industrial urea phosphate standard (GB / T27805-2011), which can meet market demand. The crystallizer has low cost and flexible addition method, making it very convenient for actual production. Attached Figure Description
[0022] Figure 1The diagram shows the phase composition of urea phosphate produced by this invention; as can be seen from the diagram, urea phosphate is a crystalline phase.
[0023] Figure 2 This is a morphological image of the urea phosphate produced by this invention. As can be seen from the image, the urea phosphate is granular with a particle size of 0.1-0.5 mm. Detailed Implementation
[0024] The technical solution of the present invention will be further described in detail below with reference to the embodiments, but the scope of protection of the present invention is not limited thereto.
[0025] Unless otherwise stated, all percentages used in this invention are mass percentages.
[0026] Unless otherwise specified, all raw materials used in the following examples are common commercially available products that can be purchased directly. For example, the wet-process phosphoric acid with a P2O5 mass fraction of 30%-60% was purchased from Wengfu (Group) Co., Ltd., and its specific composition is shown in Table 1 below.
[0027]
[0028] The following comparative examples and embodiments use the production of urea phosphate by cooling crystallization as an example for relevant description.
[0029] Comparative Example 1
[0030] 50% P2O5 wet-process phosphoric acid (Fe 0.30%, Mg 0.70%, Al 0.60%, SO42-) 2- 200g of 1.50% urea and 88.7g of urea were mixed and reacted at 70℃ for 2 hours. The mixture was cooled to crystallize (cooled to 30-40℃), filtered, and the mother liquor and filter residue of urea phosphate were obtained. The filter residue was dried to obtain 111.3g of urea phosphate product. The yield of urea phosphate was 50%, and the purity of urea phosphate was ≥98%.
[0031] Example 1
[0032] A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation is as follows:
[0033] Take 3g of ethylene glycol methyl ether and add it to 200g of the urea phosphate mother liquor obtained in Comparative Example 1 (N and P2O5 mass fractions are 10% and 30%, respectively), and set aside; add 30% P2O5 wet-process phosphoric acid (Fe 0.10%, Mg 0.10%, Al 0.10%, SO42-) 2-330g of 0.20% urea and 88g of urea were mixed and reacted at 70℃ for 2 hours. Then, the mixture was concentrated to 600g with urea phosphate crystallization mother liquor containing ethylene glycol methyl ether to obtain a concentrated solution. The concentrated solution was cooled and crystallized (cooled to 30-40℃), filtered, and dried to obtain 124.5g of urea phosphate product, with a yield of about 55% and a purity of ≥98%.
[0034] Example 2
[0035] A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation is as follows:
[0036] 40% P2O5 wet-process phosphoric acid (Fe 0.20%, Mg 0.50%, Al 0.30%, SO42-) 2- 250g of 0.80% urea and 88.7g of urea were mixed at 70℃ and reacted for 2 hours. Then, 2.5g of ethylenediaminetetraacetic acid was added to the solution. The mixture was cooled to crystallize (cooled to 30-40℃), filtered, and dried to obtain 129g of urea phosphate product. The yield of urea phosphate was 58%, and the purity of urea phosphate was ≥98%.
[0037] Example 3
[0038] A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation is as follows:
[0039] Take 3.1g of citric acid and add it to 50% P2O5 wet-process phosphoric acid (Fe 0.30%, Mg 0.80%, Al 0.50%, SO42-). 2- 1.20%) 200g; then add 88.7g of urea and mix and react at 70℃ for 2 hours; cool to crystallize (cool to 30-40℃), filter and dry to obtain 124.6g of urea phosphate product, with a urea phosphate yield of 56% and a urea phosphate purity ≥98%.
[0040] Example 4
[0041] A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation is as follows:
[0042] Take 2.5 g each of ethylene glycol methyl ether and ethylenediaminetetraacetic acid, and add them to 60% P2O5 wet-process phosphoric acid (Fe 0.40%, Mg 1.40%, Al 0.80%, SO42-). 2- 166g of urea (2.0%) was mixed with 88.4g of urea and reacted at 70℃ for 2 hours; the mixture was cooled to crystallize (cooled to 30-40℃), filtered, and dried to obtain 121.9g of urea phosphate product. The yield of urea phosphate was 55%, and the purity of urea phosphate was ≥98%.
[0043] Example 5
[0044] A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation is as follows:
[0045] Take 6g each of ethylenediaminetetraacetic acid and citric acid, and add them to 300g of urea phosphate mother liquor (N and P2O5 mass fractions are 10% and 30% respectively), for later use; prepare 60% P2O5 wet-process phosphoric acid (Fe 0.60%, Mg 2.0%, Al 1.0%, SO42-). 2- 166g of 4.0% urea and 88.8g of urea were mixed at 70℃ and reacted for 2 hours. Then, the mixture was concentrated to 500g with a mother liquor of urea phosphate containing ethylenediaminetetraacetic acid and citric acid to obtain a concentrated solution. The concentrated solution was cooled and crystallized (cooled to 30-40℃), filtered, and dried to obtain 127g of urea phosphate product. The yield of urea phosphate was 57%, and the purity of urea phosphate was ≥98%.
[0046] Example 6
[0047] A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation is as follows:
[0048] 50% P2O5 wet-process phosphoric acid (Fe 0.30%, Mg 0.70%, Al 0.60%, SO42-) 2- 200g of 1.50% urea and 88.7g of urea were mixed at 70℃ and reacted for 2 hours. Then, 3.5g each of ethylene glycol methyl ether, ethylenediaminetetraacetic acid and citric acid were added to the solution. The mixture was cooled to crystallize (cooled to 30-40℃), filtered and dried to obtain 133.5g of urea phosphate product. The yield of urea phosphate was 60%, and the purity of urea phosphate was ≥98%.
Claims
1. A method for improving the yield of urea phosphate in the wet process of phosphoric acid preparation, characterized in that, The crystallizer was mixed with wet-process phosphoric acid and urea and reacted. After the reaction was completed, the mixture was cooled and crystallized, filtered, and dried to obtain urea phosphate. Alternatively, wet-process phosphoric acid can be mixed with urea and reacted. After the reaction is complete, a crystallizer or a urea phosphate mother liquor containing a crystallizer is added. Urea phosphate is then obtained by cooling, crystallizing, filtering, and drying. The crystallizing agent is one or more of ethylene glycol methyl ether and citric acid in any proportion; the purity of the prepared urea phosphate is ≥98%.
2. The method for improving the yield of urea phosphate as described in claim 1, characterized in that, The amount of crystallizer added is 0.01%-5% of the sum of the mass of wet-process phosphoric acid and urea, or the sum of the mass of wet-process phosphoric acid, urea, and urea phosphate mother liquor.
3. The method for improving the yield of urea phosphate as described in claim 1, characterized in that, React at 50-90℃ for 1-3 hours.
4. The method for improving the yield of urea phosphate as described in claim 1, characterized in that, When a mother liquor containing a crystallizer, urea phosphate, is added, the system is concentrated and then cooled for crystallization.
5. The method for improving the yield of urea phosphate as described in any one of claims 1 to 4, characterized in that, The mass fraction of P2O5 in the wet-process phosphoric acid is 20%-70%.