Production system for reducing water-soluble phosphorus of phosphogypsum by using wet-process phosphoric acid

Abstract

The utility model provides a production system for reducing phosphogypsum water-soluble phosphorus by using wet-process phosphoric acid, which comprises a membrane filtering device and is characterized in that a concentrated water outlet of the membrane filtering device is communicated with a pulping tank through a pipeline via a concentrated water delivery pump; a discharging port of the pulping tank is communicated with a feeding port of the thickener through a pipeline via an ore pulp conveying pump, a discharging port of the thickener is communicated with the reaction tank through a pipeline via a thickener underflow pump, and a discharging port of the reaction tank is communicated with the filter through a pipeline via a feeding pump. The device disclosed by the utility model can reduce water-soluble phosphorus and water-soluble fluorine in ardealite produced in the wet-process phosphoric acid industry, and has great benefits for protecting the environment and improving the phosphorus yield.

Description

Technical Field

[0001] The utility model is applied to the wet-process phosphoric acid industry, and particularly relates to a production system for reducing water-soluble phosphorus in phosphogypsum by using wet-process phosphoric acid. Background Art

[0002] Phosphogypsum is a major solid waste from the wet-process phosphoric acid industry. Conventional phosphogypsum is not treated harmlessly before being dumped in slag dumps, or the existing treatment methods are inappropriate, causing environmental pollution. Therefore, reducing the amount of water-soluble phosphorus and water-soluble fluoride in phosphogypsum produced by the wet-process phosphoric acid industry is of great benefit to environmental protection and improving phosphorus yield. Utility Model Content

[0003] In order to solve the above problems, the utility model aims to provide a production system for reducing water-soluble phosphorus in phosphogypsum by using wet-process phosphoric acid.

[0004] The technical solution of this utility model is as follows:

[0005] A production system for reducing water-soluble phosphorus in phosphogypsum by using wet-process phosphoric acid, the system comprising a membrane filtration device, wherein a concentrated water outlet of the membrane filtration device is connected to a pulping tank via a pipeline via a concentrated water delivery pump, a discharge port of the pulping tank is connected to a thickener inlet via a pipeline via a slurry delivery pump, a discharge port of the thickener is connected to a reaction tank via a pipeline via a thickener underflow pump, and a discharge port of the reaction tank is connected to a filter via a pipeline via a feed pump.

[0006] Preferably, the water outlet of the membrane filtration device is connected to the filter through a pipeline via a water delivery pump.

[0007] Preferably, the reaction tank is provided with an acid adding pipeline; and the slurrying tank is provided with a phosphate rock feeding port.

[0008] Preferably, a concentrated water delivery pump is provided on the pipeline connecting the membrane filtration device and the pulping tank, a slurry delivery pump is provided on the pipeline connecting the pulping tank and the thickener, a thickener underflow pump is provided on the pipeline connecting the thickener and the reaction tank, a fourth delivery device feeding pump is provided on the pipeline connecting the reaction tank and the filter, and a produced water delivery pump is provided on the pipeline connecting the membrane filtration device and the filter.

[0009] Preferably, the membrane filtration device is composed of a vertical flow sedimentation tank, a water purifier, a homogenization regulating tank, an ultrafiltration component, and a reverse osmosis component connected in sequence; the membrane filtration device can treat high-phosphorus wastewater with a P2O5 concentration between 10,000 and 20,000 ppm.

[0010] The method using the system includes the following steps:

[0011] (1) The wastewater generated during the wet-process phosphoric acid production process is treated by a membrane filtration device to obtain concentrated water and product water;

[0012] (2) mixing the concentrated water obtained in step (1) with phosphate rock to obtain phosphate rock slurry;

[0013] (3) thickening the phosphate concentrate slurry obtained in step (2) to obtain phosphate concentrate slurry;

[0014] (4) mixing the phosphate concentrate slurry obtained in step (3) with acid to produce wet-process phosphoric acid slurry;

[0015] (5) filtering the slurry obtained in step (4) to obtain wet-process phosphoric acid;

[0016] (6) The produced water obtained in step (1) is added to the filter as the third washing water to clean the phosphogypsum.

[0017] Preferably, the mass concentration of the phosphate slurry in step (2) is 50%-60%.

[0018] Preferably, the solid content of the concentrate slurry in step (3) is 62%-70%.

[0019] Preferably, the solid content of the wet-process phosphoric acid slurry in step (4) is 25%-30%.

[0020] Preferably, the mass ratio of the concentrate slurry to the acid in step (4) is 1-1.5:1

[0021] Preferably, the acid in step (4) is concentrated sulfuric acid with a mass concentration of 98%-98.5%.

[0022] The beneficial effects of the utility model are:

[0023] The wastewater generated during the wet-process phosphoric acid production process is treated by a membrane filtration device. The resulting concentrated water is mixed with phosphate rock to obtain phosphate rock slurry, which is then thickened to obtain phosphate concentrate slurry. The phosphate concentrate slurry is mixed with acid to obtain wet-process phosphoric acid slurry. The slurry is filtered to obtain wet-process phosphoric acid. The produced water obtained after treatment by the membrane filtration device is added to the filter as third-wash water to clean the phosphogypsum, thereby reducing the water-soluble phosphorus content of the phosphogypsum. Both the concentrated water and the produced water are utilized, reducing the water-soluble phosphorus and water-soluble fluorine produced in the phosphogypsum in the wet-process phosphoric acid industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the utility model system;

[0025] In the figure: membrane filtration device 1, concentrated water delivery pump 2, pulping tank 3, phosphate rock feeding port 3-1, slurry delivery pump 4, thickener 5, thickener underflow pump 6, reaction tank 7, feeding pump 8, filter 9, produced water delivery pump 10. DETAILED DESCRIPTION

[0026] The following will be combined with the specific embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Phosphate rock: from the Yidu Xingfa beneficiation unit, with a P2O5 content of 31.5%, an Al2O3 content of 1.98%, a MgO content of 0.78%, and a SiO2 content of 10.77%;

[0028] The high-phosphorus wastewater comes from the sewage regulating tank of Yidu Xingfa phosphogypsum reservoir, with a P2O5 content of 13200ppm, a COD content of 150mg / L, and a pH of 2.2.

[0029] Example 1

[0030] A production system for reducing water-soluble phosphorus in phosphogypsum by using wet-process phosphoric acid, the system comprising a membrane filtration device 1, wherein a concentrated water outlet of the membrane filtration device 1 is connected to a pulping tank 3 via a pipeline through a concentrated water delivery pump 2, a discharge port of the pulping tank 3 is connected to an inlet of a thickener 5 via a pipeline through a slurry delivery pump 4, a discharge port of the thickener 5 is connected to a reaction tank 7 via a pipeline through a thickener underflow pump 6, and a discharge port of the reaction tank 7 is connected to a filter 9 via a pipeline through a feed pump 8.

[0031] Preferably, the produced water outlet of the membrane filtration device 1 is connected to the filter 9 through a pipeline via a produced water delivery pump 10 .

[0032] Preferably, the reaction tank 7 is provided with an acid adding pipeline; and the slurry making tank 3 is provided with a phosphate rock feeding port.

[0033] Preferably, a concentrated water delivery pump 2 is provided on the pipeline connecting the membrane filtration device 1 and the pulping tank 3, a slurry delivery pump 4 is provided on the pipeline connecting the pulping tank 3 and the thickener 5, a thickener underflow pump 6 is provided on the pipeline connecting the thickener 5 and the reaction tank 7, a fourth delivery device feeding pump 8 is provided on the pipeline connecting the reaction tank 7 and the filter 9, and a produced water delivery pump 10 is provided on the pipeline connecting the membrane filtration device 1 and the filter 9.

[0034] Preferably, the membrane filtration device 1 is composed of a vertical flow sedimentation tank, a water purifier, a homogenization regulating tank, an ultrafiltration component, and a reverse osmosis component connected in sequence; the membrane filtration device 1 can treat high-phosphorus wastewater with a P2O5 concentration between 10,000 and 20,000 ppm.

[0035] Example 2

[0036] Method for reducing water-soluble phosphorus in phosphogypsum using the above device:

[0037] (1) The wastewater generated during the wet-process phosphoric acid production process is treated by a membrane filtration device to obtain concentrated water with a P2O5 content of 26,000 ppm and produced water with a P2O5 content of 150 ppm;

[0038] (2) mixing the concentrated water obtained in step (1) with phosphate rock to obtain a phosphate rock slurry with a solid content of 60%;

[0039] (3) thickening the phosphate concentrate slurry obtained in step (2) to obtain a phosphate concentrate slurry having a phosphorus content of 32.1%;

[0040] (4) mixing the phosphate concentrate slurry obtained in step (3) with acid to produce a wet-process phosphoric acid slurry having a solid content of 27%;

[0041] (5) filtering the slurry obtained in step (4) to obtain wet-process phosphoric acid;

[0042] (6) The produced water obtained in step (1) is added to a filter as the third washing water to clean the phosphogypsum, thereby obtaining phosphogypsum with a water-soluble phosphorus content of 0.41%.

[0043] It has been calculated that for every 100 tons of phosphoric acid (equivalent to P2O5) produced, 321.7 tons of phosphate concentrate (dry basis) are consumed, the phosphorus recovery rate is 96.89%, and the total phosphorus content of phosphogypsum is 0.68%.

[0044] Example 3

[0045] The method and steps are the same as those in Example 1, except that the solid content of the concentrate slurry in step (1) is adjusted to 50% to prepare wet-process phosphoric acid.

[0046] It has been calculated that for every 100 tons of phosphoric acid (equivalent to P2O5) produced, 320 tons of phosphate concentrate (dry basis) are consumed, the phosphorus yield is 97.25%, the water-soluble phosphorus in phosphogypsum is 0.32%, and the total phosphorus is 0.6%.

[0047] Comparative Example 1

[0048] The method and steps are the same as those in Example 1, except that the third wash water in step (6) is replaced with high-phosphorus wastewater from the sewage regulating tank of the Yidu Xingfa phosphogypsum depot to prepare wet-process phosphoric acid.

[0049] It has been calculated that for every 100 tons of phosphoric acid (equivalent to P2O5) produced, 328.2 tons of phosphate concentrate (dry basis) are consumed, the phosphorus yield is 94.97%, the water-soluble phosphorus in phosphogypsum is 0.9%, and the total phosphorus is 1.1%.

[0050] The above embodiments are used to explain the technical solutions of the present invention. However, the present invention is not limited to the above embodiments, which does not mean that the present invention must rely on the above specific embodiments to be implemented. Any improvements made by those skilled in the art based on the present invention, or equivalent replacement of materials used in the present invention, etc., shall fall within the scope of protection of the patent.

Claims

1. A production system for reducing water-soluble phosphorus in phosphogypsum using wet-process phosphoric acid, the system comprising a membrane filtration device (1), characterized in that: The concentrated water outlet of the membrane filtration device (1) is connected to the pulping tank (3) through a pipeline via a concentrated water delivery pump (2); the discharge port of the pulping tank (3) is connected to the feed port of the thickener (5) through a pipeline via a slurry delivery pump (4); the discharge port of the thickener (5) is connected to the reaction tank (7) through a pipeline via a thickener underflow pump (6); and the discharge port of the reaction tank (7) is connected to the filter (9) through a pipeline via a feeding pump (8).

2. The production system for reducing water-soluble phosphorus in phosphogypsum using wet-process phosphoric acid according to claim 1, characterized in that: The water outlet of the membrane filtration device (1) is connected to the filter (9) via a pipeline through a water delivery pump (10).

3. The production system for reducing water-soluble phosphorus in phosphogypsum using wet-process phosphoric acid according to claim 1, characterized in that: The reaction tank (7) is provided with an acid adding pipeline; the pulping tank (3) is provided with a phosphate rock feeding port.

4. The production system for reducing water-soluble phosphorus in phosphogypsum using wet-process phosphoric acid according to claim 2, characterized in that: A concentrated water delivery pump (2) is provided on the pipeline connecting the membrane filtration device (1) and the pulping tank (3), a slurry delivery pump (4) is provided on the pipeline connecting the pulping tank (3) and the thickener (5), a thickener underflow pump (6) is provided on the pipeline connecting the thickener (5) and the reaction tank (7), a fourth delivery device feeding pump (8) is provided on the pipeline connecting the reaction tank (7) and the filter (9), and a produced water delivery pump (10) is provided on the pipeline connecting the membrane filtration device (1) and the filter (9).

5. The production system for reducing water-soluble phosphorus in phosphogypsum using wet-process phosphoric acid according to claim 1, characterized in that: The membrane filtration device (1) is composed of a vertical flow sedimentation tank, a water purifier, a homogenization regulating tank, an ultrafiltration component, and a reverse osmosis component connected in sequence; the membrane filtration device (1) is capable of treating high-phosphorus wastewater with a P2O5 concentration between 10,000 and 20,000 ppm.

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