Enhanced refined phosphoric acid arsenic removal device and arsenic removal method thereof

Abstract

The invention provides an intensified refined phosphoric acid arsenic removal device and an arsenic removal method thereof.The device comprises a multi-stage intensified refining tower, a plurality of intensified units are vertically arranged in the multi-stage intensified refining tower, and a gas outlet is formed in the top of the multi-stage intensified refining tower; a liquid phase feed port and a solid phase feed port are formed in the bottom of the multi-stage reinforced refining tower, a circulating feed port is further formed in the middle section of the multi-stage reinforced refining tower, and a discharge port is formed in the bottom of the multi-stage reinforced refining tower. The multi-stage reinforced refining tower is used, so that the contact area between the raw materials is increased, the mass transfer efficiency and the reaction efficiency are improved, the raw materials are converted into microbubbles through the reinforced unit while the hydrolysis of the raw materials is accelerated, the residence time between the raw materials is greatly prolonged, and the arsenic removal reaction is fully carried out.

Description

Technical Field

[0001] The invention belongs to the technical field of purification, and in particular relates to an enhanced refined phosphoric acid arsenic removal device and an arsenic removal method thereof. Background Art

[0002] Food phosphoric acid has a wide range of uses in many fields such as edible gelatin and medical capsules, monosodium glutamate, toothpaste, beverages, and brewing, and is in great demand. Food phosphoric acid is usually obtained by refining industrial phosphoric acid. However, in the production process of general industrial phosphoric acid, impurities such as arsenic and chlorine are contained. To prepare food phosphoric acid, the arsenic element must be reduced to below 0.5ppm. The basic principle of the existing dearsenicization process is to add sulfide to the system, react it with trivalent arsenic to convert it into arsenic trisulfide precipitation, and then remove it by filtration. The source of sulfide mostly comes from hydrogen sulfide, sodium sulfide, phosphorus pentasulfide, etc. In order to prevent the introduction of sodium ion impurities, sodium sulfide is no longer used in phosphoric acid refining. Hydrogen sulfide is a very dangerous gas and is not suitable for industrial applications. Therefore, the ideal sulfide donor is phosphorus pentasulfide. The principle is based on the hydrolysis of phosphorus pentasulfide and then reacting with arsenic. However, phosphorus pentasulfide is a solid, and its hydrolysis rate in cold and hot phosphoric acid is relatively slow. Moreover, a large part of the converted hydrogen sulfide gas directly escapes from the system into the tail gas under heating conditions, which not only wastes the sulfur element, but also increases the cost of tail gas treatment and safety control costs. In addition, the contact time between the hydrogen sulfide gas converted by its hydrolysis and phosphoric acid is relatively short, resulting in incomplete arsenic removal reaction, affecting the arsenic removal effect of phosphoric acid.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The first object of the present invention is to provide an enhanced refined phosphoric acid arsenic removal device, which uses a multi-stage enhanced refining tower to enhance the contact area between raw materials, improve mass transfer efficiency and reaction efficiency, and accelerate the hydrolysis of raw materials while converting the raw materials into microbubbles through the enhanced unit, thereby greatly extending the residence time between the raw materials, so that the arsenic removal reaction can be fully carried out.

[0005] The second object of the present invention is to provide a method for removing arsenic. The method adopts phosphorus pentasulfide as a raw material, hydrolyzes it to form hydrogen sulfide gas, and breaks the hydrogen sulfide gas into microbubbles so that the method can be carried out more fully and thoroughly.

[0006] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted: A device for removing arsenic from enhanced refined phosphoric acid comprises a multi-stage enhanced refining tower, wherein a plurality of enhanced units are vertically arranged in the multi-stage enhanced refining tower, a gas outlet is arranged at the top of the multi-stage enhanced refining tower, a liquid phase feed inlet and a solid phase feed inlet are arranged at the bottom of the multi-stage enhanced refining tower, a circulating feed inlet is also arranged on the multi-stage enhanced refining tower, and a discharge port is arranged at the bottom of the multi-stage enhanced refining tower.

[0007] In the present invention, phosphoric acid dearsenication is achieved by adopting a multi-stage enhanced refining tower, wherein the present invention adopts phosphorus pentasulfide as a raw material, and introduces phosphorus pentasulfide and phosphoric acid into the refining tower through a solid phase feed port and a liquid phase feed port arranged at the bottom of the multi-stage enhanced refining tower. Since phosphorus pentasulfide is in a solid phase before entering the refining tower, it will be hydrolyzed when introduced into the refining tower to quickly form hydrogen sulfide gas. Subsequently, the hydrogen sulfide gas and phosphoric acid are treated by the enhanced unit, so that the hydrogen sulfide gas is broken into microbubbles, so that it is evenly dispersed in the phosphoric acid liquid, thereby increasing the contact area and contact time between phosphoric acid and hydrogen sulfide, and further improving the dearsenication effect of hydrogen sulfide on phosphoric acid. The enhanced refined phosphoric acid dearsenication device provided by the present invention has good safety itself, and the arrangement of the enhanced unit and the multi-stage enhanced refining tower can greatly reduce the use of phosphorus pentasulfide, thereby greatly improving the utilization rate of hydrogen sulfide and reducing the emission of hydrogen sulfide, so that the device itself has better safety.

[0008] Preferably, as a further implementable solution, the multi-stage enhanced refining tower is a two-stage enhanced refining tower, and the two-stage enhanced refining tower includes a primary refining tower and a secondary refining tower.

[0009] Preferably, as a further implementable scheme, two strengthening units are arranged in the first-level refining tower, wherein the two strengthening units are respectively a first strengthening unit and a second strengthening unit, the first strengthening unit is arranged at the bottom of the first-level refining tower, and the second strengthening unit is arranged at the top of the first-level refining tower; the circulating feed port is arranged above the second strengthening unit; the liquid phase feed port and the solid phase feed port lead into the first strengthening unit; a sieve plate is arranged above the first strengthening unit, and a spray layer is arranged above the second strengthening unit.

[0010] Preferably, as a further implementable scheme, a third strengthening unit is provided on the top of the secondary refining tower, a feed port is provided on the secondary refining tower, the feed port leads to the third strengthening unit, and the feed port is connected to the gas outlet; a first circulation feed port and a second circulation feed port are respectively provided on the middle sections on both sides of the secondary refining tower, and a discharge port is also provided at the bottom of the secondary refining tower.

[0011] In the present invention, a two-stage enhanced refining tower is mainly adopted, wherein the two-stage enhanced refining tower mainly includes a primary refining tower and a secondary refining tower, and two enhanced units are arranged inside the primary refining tower, and the two enhanced units are respectively a first enhanced unit and a second enhanced unit, the first enhanced unit is arranged at the bottom of the primary refining tower, and the second enhanced unit is arranged at the top of the primary refining tower, at this time, phosphorus pentasulfide and phosphoric acid are introduced into the primary enhanced refining tower through a liquid phase feed port and a solid phase feed port arranged at the bottom of the primary refining tower, and then phosphorus pentasulfide will be violently hydrolyzed when it meets water when introduced into the primary refining tower, thereby generating a large amount of hydrogen sulfide gas, hydrogen sulfide gas and phosphoric acid The hydrogen sulfide gas is introduced into the first strengthening unit together. At this time, after being processed by the first strengthening unit, the hydrogen sulfide gas is broken into microbubbles so that it can be evenly dispersed in the phosphoric acid liquid. By reducing the size of the hydrogen sulfide gas, the contact area and reaction time between hydrogen sulfide and phosphoric acid are increased, so that the arsenic removal reaction is more sufficient and thorough. The present invention also arranges a sieve plate above the first strengthening unit. Since the sieve plate has evenly distributed trumpet-shaped guide ports with guiding functions, it is ensured that the hydrogen sulfide broken into microbubbles can be dispersed to both sides, avoiding the irregular dispersion of hydrogen sulfide due to excessive accumulation of microbubbles in the center of the reactor, thereby affecting the arsenic removal effect of phosphoric acid.

[0012] Subsequently, after being treated in the primary refining tower, the reaction liquid gradually rises, and then passes through the second enhanced unit arranged at the top of the primary enhanced refining tower again to further improve the arsenic removal efficiency of hydrogen sulfide for phosphoric acid. At the same time, when the first circulation pump extracts the reaction liquid in the reaction tower and enters the primary enhanced refining tower again through the circulation feed port, the reaction liquid will be sprayed through the spray layer arranged above the second enhanced unit, thereby achieving preliminary crushing of the reaction liquid, and then the reaction liquid circulating from the top can be sprayed to initially form a stable gas-liquid mixture, so that the residence time of the hydrogen sulfide gas in the phosphoric acid can be increased during the descent of the reaction liquid in the primary refining tower, and then when the reaction liquid circulates into the primary refining tower, the hydrogen sulfide gas can be more evenly dispersed in the phosphoric acid after being treated by the second enhanced unit, thereby further improving the arsenic removal effect of phosphoric acid.

[0013] Subsequently, the incompletely reacted hydrogen sulfide gas will flow out from the gas outlet arranged at the top of the first refining tower, and then be introduced into the second refining tower through the feed port arranged at the top of the second refining tower, and then be introduced into the third enhanced unit together with the reaction liquid introduced from the first circulation feed port, so that the incompletely reacted hydrogen sulfide gas is broken into microbubbles, which are mixed with the introduced reaction liquid to increase the residence time of hydrogen sulfide in phosphoric acid and increase the contact area between the two, thereby improving the arsenic removal effect of phosphoric acid.

[0014] Therefore, the present invention sets a multi-stage enhanced refining tower, combined with the setting of sieve plates and spray layers to further increase the contact area and contact time between the raw materials, thereby greatly improving the efficiency of the arsenic removal reaction. Compared with the prior art, the arsenic removal device used in the present invention can well avoid the danger caused by direct use of hydrogen sulfide, and has excellent arsenic removal effect, fast reaction rate, and excellent arsenic removal effect.

[0015] Preferably, as a further implementable solution, a first circulation pump is further provided between the circulation feed port and the discharge port, and the first circulation pump is connected to the first circulation feed port.

[0016] Preferably, as a further implementable solution, the discharge port arranged at the bottom of the secondary refining tower is connected to the second circulation feed port, and a second circulation pump is further arranged between the discharge port and the second circulation feed port.

[0017] Preferably, as a further implementable solution, a separation tower is further included; the separation tower is connected to the secondary refining tower via the second circulation pump.

[0018] Preferably, as a further implementable solution, a tail gas outlet is provided at the top of the separation tower, and a discharge port and a circulating pump feed port are respectively provided on both sides of the bottom of the separation tower, and the circulating pump feed port is connected to the second circulating pump.

[0019] Preferably, as a further implementable solution, a packing is provided in the separation tower, and the distance between the packing and the top of the separation tower is 2-3 times the distance between the packing and the bottom of the separation tower.

[0020] The present invention also provides a method for removing arsenic by the enhanced carbon dioxide capture system, comprising the following steps: After phosphoric acid and phosphorus pentasulfide are introduced in sequence, the hydrogen sulfide produced by the hydrolysis of phosphorus pentasulfide is broken into microbubbles and mixed to perform an enhanced arsenic removal reaction.

[0021] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention provides an enhanced refined phosphoric acid arsenic removal device, which uses a multi-stage enhanced refining tower to enhance the contact area between raw materials, improve mass transfer efficiency and reaction efficiency, and accelerate the hydrolysis of raw materials while converting the raw materials into microbubbles through the enhanced unit, thereby greatly extending the residence time between the raw materials, so that the arsenic removal reaction can be fully carried out.

[0022] (2) The present invention provides a method for removing arsenic from phosphorus pentasulfide. The method uses phosphorus pentasulfide as a raw material to hydrolyze it to form hydrogen sulfide gas, and breaks the hydrogen sulfide gas into microbubbles so that the method for removing arsenic from phosphorus pentasulfide is more thorough. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] By reading the detailed description of the preferred embodiment below, various other advantages and benefits will become clear to those of ordinary skill in the art. The accompanying drawings are only used for the purpose of illustrating the preferred embodiment and are not considered to be limitations of the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. Figure 1 This is a structural diagram of an enhanced refined phosphoric acid arsenic removal device of the present invention. In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Primary refining tower; 2. First strengthening unit; 3. Spray layer; 4. Second strengthening unit; 5. Sieve plate; 6. First circulation pump; 7. Secondary refining tower; 8. Third strengthening unit; 9. Second circulation pump; 10. Packing; 11. Separation tower. DETAILED DESCRIPTION

[0024] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0025] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0027] In order to more clearly explain the technical solution of the present invention, it is described in the form of specific embodiments below.

[0028] Example 1 See also Figure 1 The present invention is an enhanced refined phosphoric acid arsenic removal device, which includes 1. a primary refining tower; 2. a first enhanced unit; 3. a spray layer; 4. a second enhanced unit; 5. a sieve plate; 6. a first circulation pump; 7. a secondary refining tower; 8. a third enhanced unit; 9. a second circulation pump; 10. a filler; and 11. a separation tower.

[0029] The enhanced refined phosphoric acid arsenic removal device of the present invention mainly comprises a primary refining tower 1 and a secondary refining tower 7, wherein two strengthening units are arranged in the primary refining tower, wherein the two strengthening units are respectively a first strengthening unit 2 and a second strengthening unit 4, and the first strengthening unit 2 is arranged below the circulating feed port, and a liquid phase feed port and a solid phase feed port are arranged at the bottom of the primary refining tower, and a sieve plate 5 is arranged below the first strengthening unit, and a spray layer 3 is arranged above the second strengthening unit; A third strengthening unit 8 is provided at the top of the secondary refining tower 7, a feed port is provided above the third strengthening unit 8, and the feed port above the third strengthening unit 8 is connected to the discharge port provided at the top of the primary refining tower 1, wherein the middle sections on both sides of the secondary refining tower 7 are respectively provided with a first circulation feed port and a second circulation feed port, and a discharge port is also provided at the bottom of the secondary refining tower 7; A first circulation pump 6 is provided between the circulation feed port provided on the first refining tower and the discharge port provided at the bottom of the first refining tower, and the first circulation pump 6 is connected to the first circulation feed port provided on the side of the middle section of the second refining tower 7; The discharge port at the bottom of the secondary refining tower 7 is connected to the second circulation feed port on the side of the primary refining tower, and a second circulation pump 9 is provided between the discharge port and the second circulation feed port; The present invention also includes a separation tower 11, which is connected to the secondary refining tower 7 through the second circulating pump 9, and a tail gas outlet is also provided at the top of the separation tower, and a feed port and a circulating pump feed port are respectively provided on both sides of the bottom of the separation tower, and the circulating pump feed port is connected to the second circulating pump 9; and a packing 10 is also provided inside the separation tower, and the distance between the packing and the bottom of the separation tower 10 is twice the distance between the packing and the top of the separation tower 10; The arsenic removal method of the present invention specifically comprises the following steps: phosphoric acid and phosphorus pentasulfide are introduced into the primary refining tower 1 through the liquid phase feed port and the solid phase feed port provided on the side of the primary refining tower 1; phosphorus pentasulfide is then hydrolyzed in the primary refining tower 1 to produce hydrogen sulfide, which enters the first strengthening unit 2 located at the bottom of the primary refining tower 1 together with the phosphoric acid; the hydrogen sulfide gas is broken into microbubbles by the treatment of the first strengthening unit, and then the hydrogen sulfide is evenly dispersed in the phosphoric acid through the sieve plate 5 provided above the first strengthening unit; in this way, the residence time and contact area of ​​hydrogen sulfide in the phosphoric acid can be well increased; Then, the first circulation pump 6 will draw the reaction liquid from the bottom of the primary refining tower 1 and re-enter the primary refining tower 1 from the circulation feed port set at the top of the primary refining tower 1, and the reaction liquid will be preliminarily crushed by the spray layer 3 set above the second strengthening unit 4, so that the hydrogen sulfide gas is dispersed in the reaction liquid to form a uniform mixture, and then enter the second strengthening unit 4 together. After being processed by the second strengthening unit 4, the hydrogen sulfide gas can be further evenly dispersed in the reaction liquid, further improving the arsenic removal effect; The unreacted hydrogen sulfide gas will flow out from the gas outlet provided at the top of the primary refining tower 1, enter the secondary refining tower 7 through the feed port provided at the top of the secondary refining tower 7, and enter the secondary refining tower 7 together with the reaction liquid pumped out by the first circulation pump 6. After being processed by the third strengthening unit 8, the hydrogen sulfide gas is evenly dispersed in the reaction liquid, so that the hydrogen sulfide can further react completely. Then the second circulation pump 9 will pump out the reaction liquid inside the secondary refining tower 7, and enter the secondary refining tower 7 from the second circulation feed port set at the top of the secondary refining tower 7 for further arsenic removal reaction; The reaction liquid treated by the secondary refining tower 7 is pumped out by the second circulation pump 9 and sent to the separation tower 11. The reaction liquid is separated into gas and liquid through the setting of the filler 10. The reaction liquid after arsenic removal is discharged from the discharge port set at the bottom of the separation tower 10, and the exhaust gas is discharged from the exhaust gas outlet set at the top.

[0030] Example 2 The enhanced refined phosphoric acid arsenic removal device of the present invention mainly comprises a primary refining tower 1 and a secondary refining tower 7, wherein two strengthening units are arranged in the primary refining tower, wherein the two strengthening units are respectively a first strengthening unit 2 and a second strengthening unit 4, and the first strengthening unit 2 is arranged below the circulating feed port, and a liquid phase feed port and a solid phase feed port are arranged at the bottom of the primary refining tower, and a sieve plate 5 is arranged below the first strengthening unit, and a spray layer 3 is arranged above the second strengthening unit; A third strengthening unit 8 is provided at the top of the secondary refining tower 7, a feed port is provided above the third strengthening unit 8, and the feed port above the third strengthening unit 8 is connected to the discharge port provided at the top of the primary refining tower 1, wherein the middle sections on both sides of the secondary refining tower 7 are respectively provided with a first circulation feed port and a second circulation feed port, and a discharge port is also provided at the bottom of the secondary refining tower 7; A first circulation pump 6 is provided between the circulation feed port provided on the first refining tower and the discharge port provided at the bottom of the first refining tower, and the first circulation pump 6 is connected to the first circulation feed port provided on the side of the middle section of the second refining tower 7; The discharge port at the bottom of the secondary refining tower 7 is connected to the second circulation feed port on the side of the primary refining tower, and a second circulation pump 9 is provided between the discharge port and the second circulation feed port; The present invention also includes a separation tower 11, which is connected to the secondary refining tower 7 through the second circulating pump 9, and a tail gas outlet is also provided at the top of the separation tower, and a feed port and a circulating pump feed port are respectively provided on both sides of the bottom of the separation tower, and the circulating pump feed port is connected to the second circulating pump 9; and a packing 10 is also provided inside the separation tower, and the distance between the packing and the bottom of the separation tower 10 is 3 times the distance between the packing and the top of the separation tower 10; The arsenic removal method of the present invention specifically comprises the following steps: phosphoric acid and phosphorus pentasulfide are introduced into the primary refining tower 1 through the liquid phase feed port and the solid phase feed port provided on the side of the primary refining tower 1; phosphorus pentasulfide is then hydrolyzed in the primary refining tower 1 to produce hydrogen sulfide, which enters the first strengthening unit 2 located at the bottom of the primary refining tower 1 together with the phosphoric acid; the hydrogen sulfide gas is broken into microbubbles by the treatment of the first strengthening unit, and then the hydrogen sulfide is evenly dispersed in the phosphoric acid through the sieve plate 5 provided above the first strengthening unit; in this way, the residence time and contact area of ​​hydrogen sulfide in the phosphoric acid can be well increased; Then, the first circulation pump 6 will draw the reaction liquid from the bottom of the primary refining tower 1 and re-enter the primary refining tower 1 from the circulation feed port set at the top of the primary refining tower 1, and the reaction liquid will be preliminarily crushed by the spray layer 3 set above the second strengthening unit 4, so that the hydrogen sulfide gas is dispersed in the reaction liquid to form a uniform mixture, and then enter the second strengthening unit 4 together. After being processed by the second strengthening unit 4, the hydrogen sulfide gas can be further evenly dispersed in the reaction liquid, further improving the arsenic removal effect; The unreacted hydrogen sulfide gas will flow out from the gas outlet provided at the top of the primary refining tower 1, enter the secondary refining tower 7 through the feed port provided at the top of the secondary refining tower 7, and enter the secondary refining tower 7 together with the reaction liquid pumped out by the first circulation pump 6. After being processed by the third strengthening unit 8, the hydrogen sulfide gas is evenly dispersed in the reaction liquid, so that the hydrogen sulfide can further react completely. Then the second circulation pump 9 will pump out the reaction liquid inside the secondary refining tower 7, and enter the secondary refining tower 7 from the second circulation feed port set at the top of the secondary refining tower 7 for further arsenic removal reaction; The reaction liquid treated by the secondary refining tower 7 is pumped out by the second circulation pump 9 and sent to the separation tower 11. The reaction liquid is separated into gas and liquid through the setting of the filler 10. The reaction liquid after arsenic removal is discharged from the discharge port set at the bottom of the separation tower 10, and the exhaust gas is discharged from the exhaust gas outlet set at the top.

[0031] Experimental Example 1: Verification of the feasibility of phosphorus pentasulfide arsenic removal experiment The liquid temperature is 75-80°C. Calculate P according to the reaction equation 2 S 5 The theoretical demand was then tested with 4 times, 8 times, 12 times and 16 times the amount of feed, with a reaction time of 30 minutes. 2 S 5 The arsenic removal effect is shown in Table 1: Table 1 Different P 2 S 5 Effect of feed amount on arsenic removal effect

[0032] From the results analysis, it can be found that 16 times the amount is close to the requirement but still cannot fully meet the arsenic removal requirements, while 4 times, 8 times and 12 times the amount have poor arsenic removal effects. 2 S 5 Hydrolysis is performed by first hydrolyzing with hot water to produce H 2 S has more escape and is wasted. On the other hand, due to P 2 S 5 Excess, that is, there is excess S in phosphoric acid 2- , the remaining As 2 S 3 Therefore, from the above experimental results, it can be known that phosphorus pentasulfide has a certain effect on arsenic removal from phosphate, but due to its low hydrolysis efficiency and H 2 The S utilization rate is low, resulting in low arsenic removal efficiency of phosphorus pentasulfide.

[0033] Table 2 Verification of arsenic removal performance under enhanced unit By debugging the equipment and improving P 2 S 5 The feeding method, etc., ultimately achieved continuous and stable operation of the equipment. On this basis, the equipment was continuously monitored for several days, sampling was performed every 30min / 60min, and As was removed by membrane separation. 2 S3 The arsenic content in phosphoric acid after precipitation is shown in Table 2 below.

[0034] Table 2 Continuous arsenic removal test results of arsenic removal equipment

[0035] The data in Table 2 show that the removal of arsenic from crude phosphoric acid can be achieved continuously and stably by setting up an enhanced unit. Compared with the arsenic removal equipment without an enhanced unit, the arsenic removal time of the enhanced unit is about 30-35 minutes. Therefore, it can be known that the setting of the enhanced unit can shorten the arsenic removal reaction time. This is because the use of the enhanced unit can effectively improve the hydrolysis efficiency of phosphorus pentasulfide, and increase the gas-liquid contact reaction speed during the reaction of sulfur and arsenic, improve the reaction efficiency, and thus shorten the reaction time.

[0036] The second experimental data in Table 2 also show that about 16 times the amount of P required in Experimental Example 1 2 S 5 In order to achieve a better arsenic removal effect, the device of the present invention can greatly reduce P 2 S 5 Therefore, based on the pilot arsenic removal test results, in the industrial production process, the arsenic removal equipment provided by the present invention can effectively reduce P 2 S 5 It can also reduce the dosage, improve equipment safety, and reduce pollutant gas emissions; it can also shorten the reaction residence time and improve the processing efficiency of the equipment.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An enhanced refined phosphoric acid arsenic removal device, characterized in that: It comprises a multi-stage enhanced refining tower, wherein a plurality of enhancing units are vertically arranged in the multi-stage enhanced refining tower, a gas outlet is arranged at the top of the multi-stage enhanced refining tower, a liquid phase feed inlet and a solid phase feed inlet are arranged at the bottom of the multi-stage enhanced refining tower, a circulating feed inlet is also arranged on the multi-stage enhanced refining tower, and a discharge port is arranged at the bottom of the multi-stage enhanced refining tower.

2. The enhanced refined phosphoric acid arsenic removal device according to claim 1, characterized in that: The multi-stage enhanced refining tower is a two-stage enhanced refining tower, and the two-stage enhanced refining tower includes a primary refining tower and a secondary refining tower.

3. The enhanced refined phosphoric acid arsenic removal device according to claim 2, characterized in that: Two strengthening units are arranged in the first-level refining tower, wherein the two strengthening units are respectively a first strengthening unit and a second strengthening unit, the first strengthening unit is arranged at the bottom of the first-level refining tower, and the second strengthening unit is arranged at the top of the first-level refining tower; the circulating feed port is arranged above the second strengthening unit; the liquid phase feed port and the solid phase feed port lead into the first strengthening unit; a sieve plate is arranged above the first strengthening unit, and a spray layer is arranged above the second strengthening unit.

4. The enhanced refined phosphoric acid arsenic removal device according to claim 2, characterized in that: A third strengthening unit is arranged on the top of the secondary refining tower, a feed port is arranged on the secondary refining tower, the feed port leads to the third strengthening unit, and the feed port is connected to the gas outlet; a first circulation feed port and a second circulation feed port are respectively arranged in the middle sections on both sides of the secondary refining tower, and a discharge port is also arranged at the bottom of the secondary refining tower.

5. The enhanced refined phosphoric acid arsenic removal device according to claim 4, characterized in that: A first circulation pump is also provided between the circulation feed port and the discharge port, and the first circulation pump is connected to the first circulation feed port.

6. The enhanced refined phosphoric acid arsenic removal device according to claim 4, characterized in that: The discharge port arranged at the bottom of the secondary refining tower is connected to the second circulating feed port, and a second circulating pump is also arranged between the discharge port and the second circulating feed port.

7. The enhanced refined phosphoric acid arsenic removal device according to claim 6, characterized in that: It also includes a separation tower; the separation tower is connected to the secondary refining tower through the second circulation pump.

8. The enhanced refined phosphoric acid arsenic removal device according to claim 7, characterized in that: The top of the separation tower is provided with an exhaust gas outlet, and both sides of the bottom of the separation tower are respectively provided with a discharge port and a circulating pump feed port, and the circulating pump feed port is connected to the second circulating pump.

9. The enhanced refined phosphoric acid arsenic removal device according to claim 8, characterized in that: A packing is arranged in the separation tower, and the distance between the packing and the bottom of the separation tower is 2-3 times the distance between the packing and the top of the separation tower.

10. A method for removing arsenic from a reinforced refined phosphoric acid by using the arsenic removal device according to any one of claims 1 to 9, characterized in that: The following steps are involved: After phosphoric acid and phosphorus pentasulfide are introduced in sequence, the hydrogen sulfide produced by the hydrolysis of phosphorus pentasulfide is broken into microbubbles and mixed to perform an enhanced arsenic removal reaction.

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