Liquid phosphorus production system, yellow phosphorus furnace gas treatment system, and phosphoric acid production method

Abstract

The application discloses a liquid phosphorus production system, a yellow phosphorus furnace gas treatment system and a phosphoric acid production method. The liquid phosphorus production system is used for treating yellow phosphorus furnace gas and outputting liquid phosphorus, and comprises a heating device used for heating treatment of the furnace gas and outputting heated gas, a feeding device used for inputting conditioning powder into the heated gas and outputting mixed gas, wherein the conditioning powder comprises inorganic oxide powder used for absorbing moisture and acidic components in the heated gas, a filtering device used for gas-solid separation treatment of the mixed gas and outputting clean gas, and a condensing device used for condensing phosphorus vapor in the clean gas into liquid phosphorus. The liquid phosphorus production system of the application can absorb moisture and acidic components in the furnace gas by adding conditioning powder into the furnace gas, can inhibit occurrence of side reactions, can effectively prevent filter medium from forming a film, adsorption or phase change, can delay filter medium blockage, and can significantly reduce operation cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of yellow phosphorus and phosphoric acid, and in particular to a yellow phosphorus production system, a yellow phosphorus furnace gas treatment system and a phosphoric acid production method. BACKGROUND

[0002] The wet-process phosphoric acid process uses sulfuric acid to decompose phosphate rock to obtain dilute phosphoric acid and solid waste residues (referred to as phosphogypsum) mainly in the form of CaSO4·nH2O. The P2O5 concentration of the product phosphoric acid is generally 25-35%. The main disadvantages of this process are: 1. A large amount of sulfuric acid is consumed; 2. A large amount of harmful waste residue phosphogypsum is produced (4-5 tons of phosphogypsum are generally produced per ton of phosphoric acid), and the sulfuric acid, phosphoric acid and soluble fluoride contained in the phosphogypsum are dissolved in water, which is washed away by rainwater after natural piling, causing serious pollution to the environment (soil and water source); 3. The impurity content of the product phosphoric acid is high, and it is generally only used for producing fertilizers; and 4. The low product concentration leads to high transportation cost of the phosphoric acid.

[0003] Due to the above problems of the wet-process phosphoric acid process, the main phosphoric acid production methods currently used are the thermal-process phosphoric acid process and the kiln-process phosphoric acid process, both of which use phosphate rock, silica and carbonaceous reducing agents as raw materials.

[0004] The thermal-process phosphoric acid process first reduces the phosphorus in the phosphate rock into elemental phosphorus vapor and converts the carbonaceous reducing agent into CO in an electric furnace, then washes and cools the gas discharged from the electric furnace, which is mainly composed of elemental phosphorus vapor and CO, so that the elemental phosphorus vapor is cooled to separate the solid from the gas phase, obtaining the product yellow phosphorus, which is heated to a liquid phase and then reacts with the air introduced into a hydration tower to obtain phosphoric anhydride P2O5, which is then absorbed with water to obtain phosphoric acid.

[0005] The kiln-process phosphoric acid, also known as KPA method, is carried out in a rotary kiln. First, the phosphorus in the phosphate rock is reduced and volatilized in the form of elemental phosphorus vapor, which is then oxidized into phosphorus pentoxide in the middle space of the kiln by the air introduced into the kiln, and finally the kiln gas containing phosphorus pentoxide is obtained, which is then absorbed as phosphoric acid after being washed and dedusted.

[0006] Although the thermal-process phosphoric acid process does not produce a large amount of waste residue, the gas discharged from the electric furnace contains a large amount of dust, and the condensation temperature of the phosphorus vapor is low, which will cause the elemental phosphorus vapor to condense and integrate with the dust after being washed and cooled, seriously affecting the quality of the yellow phosphorus. Although the kiln-process phosphoric acid process saves a large amount of electric energy, there is a large amount of dust in the rotary kiln, which seriously affects the oxidation reaction of the phosphorus vapor, and although the condensation temperature of the phosphorus pentoxide vapor is relatively high, washing and dedusting the kiln gas will not only cause part of the phosphorus pentoxide vapor to condense, but also the dedusting effect is poor, and there is still a lot of dust in the gas after washing, so high-purity phosphoric acid cannot be obtained.

[0007] To this end, the applicant of the present application proposes a patent application with application number 2020106145565 and title of production system and production method of high-purity phosphoric acid, which physically intercepts dust in the second gas through a first filtering unit to obtain phosphorus vapor with high concentration and high purity, and then oxidizes and absorbs the phosphorus vapor to obtain high-purity phosphoric acid. However, it is found in practice that the moisture and acidic components in the furnace gas are prone to condensation, adsorption or phase change when passing through the first filtering unit, thereby causing difficulty in filtration. When the phosphorus vapor is treated by the hot process for producing phosphoric acid, the tail gas after hydration absorption is usually treated by an alkali washing tower, which requires a large amount of alkali liquor and has high tail gas treatment cost. SUMMARY

[0008] The main purpose of the present application is to provide a liquid phosphorus production system, a liquid phosphorus treatment system, a yellow phosphorus furnace gas treatment system and a phosphoric acid production method to solve the technical problems of difficult furnace gas treatment and high tail gas treatment cost in the prior art.

[0009] To achieve the above-mentioned purpose, the present application first provides a liquid phosphorus production system, and the technical scheme is as follows:

[0010] The liquid phosphorus production system is used for treating yellow phosphorus electric furnace gas and outputting liquid phosphorus, and comprises: a heating device used for heating treatment of the furnace gas and outputting heated gas; a feeding device used for inputting conditioning powder into the heated gas and outputting mixed gas; the conditioning powder comprises inorganic oxide powder used for absorbing moisture and acidic components in the heated gas; a filtering device used for gas-solid separation treatment of the mixed gas and outputting clean gas; and a condensing device used for condensing phosphorus vapor in the clean gas into liquid phosphorus.

[0011] As a further improvement of the above-mentioned liquid phosphorus production system, the heating device comprises a first heater and a second heater, and part of particulate matters in the furnace gas are naturally settled into an ash tank in the first heater.

[0012] As a further improvement of the above-mentioned liquid phosphorus production system, the temperature of the furnace gas is 130-170℃; the first heater heats the furnace gas to 170-210℃; and the second heater heats the furnace gas to 200-240℃.

[0013] As a further improvement of the above-mentioned liquid phosphorus production system, the conditioning powder comprises CaO powder and SiO2 powder.

[0014] As a further improvement of the above-mentioned liquid phosphorus production system, the mass ratio of the CaO powder and the SiO2 powder is (2-4):1.

[0015] To achieve the above-mentioned purpose, the present application further provides a liquid phosphorus treatment system, and the technical scheme is as follows:

[0016] The liquid phosphorus treatment system comprises: a combustion tower for oxidizing and combusting liquid phosphorus to generate P2O5 and output a first gas; a hydration tower for hydrating P2O5 in the first gas to generate H3PO4 and output a second gas and a first acid liquid; an absorption tower for absorbing P2O5 in the second gas and output a third gas and a second acid liquid; a tail gas treatment assembly for treating the third gas and discharging tail gas; a filtration assembly for filtering part of the first acid liquid and output finished phosphoric acid; and a reflux mechanism for flowing part of the second acid liquid into the hydration tower as an absorbent.

[0017] As a further improvement of the above liquid phosphorus treatment system, the system further comprises a compressed air pump for atomizing the liquid phosphorus and inputting the atomized liquid phosphorus into the combustion tower.

[0018] As a further improvement of the above liquid phosphorus treatment system, the system further comprises a secondary air pump for inputting secondary air into the combustion tower.

[0019] As a further improvement of the above liquid phosphorus treatment system, the system further comprises a first heat exchanger for cooling the first acid liquid.

[0020] As a further improvement of the above liquid phosphorus treatment system, the system further comprises a first spraying mechanism for spraying part of the first acid liquid into the hydration tower as an absorbent.

[0021] As a further improvement of the above liquid phosphorus treatment system, the system further comprises a second spraying mechanism for spraying part of the second acid liquid into the absorption tower as an absorbent.

[0022] As a further improvement of the above liquid phosphorus treatment system, the first gas enters from the top of the hydration tower, the second gas is discharged from the bottom of the hydration tower and then flows into the absorption tower through an upward pipeline; and the system further comprises a Venturi tube arranged between the upward pipeline and the absorption tower.

[0023] As a further improvement of the above liquid phosphorus treatment system, the system further comprises a third spraying mechanism for spraying part of the first acid liquid into the upward pipeline as an absorbent; a cooling water circulation mechanism for flowing cooling water in a jacket between the combustion tower and the Venturi tube; and the upward pipeline has a larger diameter than an inlet pipe of the absorption tower.

[0024] As a further improvement of the above liquid phosphorus treatment system, the tail gas treatment assembly comprises a mist eliminator and a separator for treating the third gas in sequence; and the filtration assembly comprises any one of a plate-and-frame filter, a metal filter cartridge, and a ceramic filter cartridge.

[0025] In order to achieve the above object, the present application further provides a yellow phosphorus furnace gas treatment system, and the technical scheme is as follows:

[0026] The yellow phosphorus furnace gas treatment system comprises the liquid phosphorus production system and / or the liquid phosphorus treatment system.

[0027] In order to achieve the above object, the present application further provides a yellow phosphorus furnace gas treatment system, and the technical scheme is as follows:

[0028] The yellow phosphorus furnace gas treatment system comprises the liquid phosphorus production system and / or the liquid phosphorus treatment system.

[0029] Firstly, the liquid phosphorus production system of the present application can effectively prevent the filter medium from being pasted, adsorbed or phase changed by adding the conditioning powder into the furnace gas to absorb the moisture and acidic components in the furnace gas and inhibit the occurrence of side reactions, thereby delaying the plugging of the filter medium and significantly reducing the operation cost. Secondly, the liquid phosphorus treatment system of the present application can reduce the use of alkali liquor and the cost of tail gas treatment by using the absorption tower to treat the tail gas after hydration absorption and using the second acid liquor after absorption as the hydration tower absorbent. The liquid phosphorus production system and the liquid phosphorus treatment system have a very simple structure, and the yellow phosphorus furnace gas treatment system formed by the two systems can directly convert the yellow phosphorus electric furnace gas into high-purity phosphoric acid, has low energy consumption, is green and environmentally friendly, and has high economic benefits. Therefore, the liquid phosphorus production system, the liquid phosphorus treatment system, the yellow phosphorus furnace gas treatment system and the phosphoric acid production method of the present application have strong practicability.

[0030] The present application will be further described below in conjunction with the drawings and specific embodiments. The additional aspects and advantages of the present application will be partially given in the following description, partially become obvious from the following description, or be understood through the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0031] The drawings that form a part of the present application are used to assist the understanding of the present application, and the content provided by the drawings and the related description in the present application can be used to explain the present application, but do not constitute an improper limitation on the present application. In the drawings:

[0032] Figure 1 It is a structure schematic view of an embodiment of the liquid phosphorus production system of the present application.

[0033] Figure 2 It is a structure schematic view of an embodiment of the liquid phosphorus treatment system of the present application.

[0034] The related marks in the above drawings are as follows:

[0035] 100 - electric furnace, 111 - first heater, 112 - second heater, 113 - ash tank, 120 - feeding device, 130 - filtering device, 140 - condensing device, 141 - phosphorus receiving tank, 150 - induced draft fan, 210 - combustion tower, 211 - compressed air pump, 212 - secondary air pump, 213 - phosphorus compression tank, 220 - hydration tower, 221 - updraft pipe, 222 - venturi, 223 - first heat exchanger, 230 - absorption tower, 241 - demister, 242 - separator, 251 - filtering assembly, 252 - finished product acid tank, 260 - reflux mechanism, 271 - soft water tank, 270 - second heat exchanger, 281 - first spraying mechanism, 282 - second spraying mechanism, 283 - third spraying mechanism. DETAILED DESCRIPTION

[0036] The present application will be described in connection with the preferred embodiments thereof as more fully illustrated in the accompanying drawings. Those skilled in the art will appreciate that the description herein is by way of illustration and not by way of limitation. Before explaining the present application in detail, it is to be understood that the application is not limited in its application to the details set forth in the following description or exemplified criteria. The application is capable of other embodiments and of being practiced or carried out in various ways.

[0037] The technical solutions and technical features provided in the present application in various parts including the following description can be combined with each other without conflict.

[0038] In addition, the embodiments of the present application involved in the following description are generally only a part of the embodiments of the present application, not all the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments in the present application without creative labor should belong to the scope of protection of the present application.

[0039] Regarding the terms and units in the present application. The terms "include", "have" and any variations thereof in the description and claims of the present application and related parts are intended to cover non-exclusive inclusion.

[0040] Figure 1 Structure schematic diagram of an embodiment of the liquid phosphorus production system of the present application.

[0041] As shown in Figure 1 The liquid phosphorus production system is used for processing the furnace gas of the yellow phosphorus electric furnace 100 and outputting liquid phosphorus, and includes a heating device, a feeding device 120, a filtering device 130 and a condensing device 140. The heating device is used for heating treatment of the furnace gas and outputs heated gas; the feeding device 120 is used for inputting conditioning powder into the heated gas and outputs mixed gas; the conditioning powder includes inorganic oxide powder for absorbing moisture and acidic components in the heated gas; the filtering device 130 is used for gas-solid separation treatment of the mixed gas and outputs clean gas; and the condensing device 140 is used for condensing phosphorus vapor in the clean gas into liquid phosphorus.

[0042] The heating device includes a primary heater 111 and a secondary heater 112. Some particulate matter in the furnace gas naturally settles into the ash container 113 in the primary heater 111, which reduces the dust content and allows for a more complete reaction between the conditioning powder and the furnace gas. The temperature of the furnace gas is 130–170°C; the primary heater 111 heats the furnace gas to 170–210°C; and the secondary heater 112 heats the furnace gas to 200–240°C. This ensures a thorough reaction between the conditioning powder and the furnace gas while minimizing phase change.

[0043] The primary heater 111 and the secondary heater 112 are electric heaters or jacketed hot gas heaters, and the hot gas is an inert gas. The feeding device 120 is a screw feeder or an inert gas feeding device.

[0044] The feeding port of the feeding device 120 is located near the gas inlet of the secondary heater 112, so that the conditioning powder can be more evenly dispersed under the action of gas turbulence.

[0045] The main components of the flue gas overflowing from the yellow phosphorus electric furnace 100 are gases such as CO, CO2, O2, N2, HF, P4, H2, H2S, and PH3, as well as dust solids such as P2O5, SiO2, and CaO. Due to the 2-5% surface moisture introduced from raw materials such as phosphate rock, silica, and reducing agents, the flue gas will contain water vapor (H2O). (g) and liquid water H2O (i) This causes the yellow phosphorus to directly convert to H3PO4 during the furnace temperature drop.

[0046] 2P4+H2O (g) →3H3PO4 + 5PH3↑

[0047] The escaped P2O5 hydrolyzes and transforms into H3PO4:

[0048] P₂O₅ + 6H₂O (g) →4H3PO4

[0049] In actual operation, electric furnace 100 occasionally creates a negative pressure state, which allows O2 from the air to mix in, leading to an increase in the escape of P2O5, which is even more pronounced in the early stages of material collapse.

[0050] P4 + O2 → P2O5

[0051] This further exacerbated the formation of H3PO4, while the polymerization reaction of H3PO4 also occurred during the production process in electric furnace 100.

[0052] 2H3PO4→H4P2O7+H2O

[0053] 3H3PO4→H5P3O 10 +2H2O

[0054] 4H3PO4→(HPO3)4+4H2O

[0055] Therefore, to avoid the occurrence of paste film and phase change when the furnace gas passes through the filter medium of the filter device 130, the conditioning powder is added before the furnace gas enters the filter device 130 to condition the furnace gas.

[0056] The conditioning powder used in the embodiment includes CaO powder and SiO2 powder; wherein:

[0057] The CaO powder can absorb the moisture and acidic components in the furnace gas, including the following reactions:

[0058] CaO+2H2O→Ca(OH)2

[0059] CaO+2H3PO4→Ca(H2PO4)2+H2O

[0060] CaO+H3PO4→CaHPO4+H2O

[0061] 3CaO+2H3PO4→Ca3(PO4)2+3H2O

[0062] CaO+2HF→CaF2+H2O

[0063] Ca(OH)2+H2S→CaS+2H2O

[0064] Ca(OH)2+2HF→CaF2+H2O

[0065] The SiO2 powder can react with CaF2 and promote SiF4 to pass through in the form of gas, so that the phase change does not occur on the surface of the filter medium, including the following reaction:

[0066] 2CaF2+3SiO2→2CaSiO3+SiF4↑

[0067]

[0068] When the mass ratio of the CaO powder and the SiO2 powder is (2-4): 1, the best conditioning effect can be achieved.

[0069] The filter device 130 preferably uses a porous metal film, which can withstand a relatively high filtration temperature. A circulating fan is required to insulate the filter device 130, which can further prevent phase change.

[0070] The condensing device 140 is preferably a washing tower, which condenses the phosphorus vapor in the clean gas into liquid phosphorus by spraying cooling water, and the liquid phosphorus falls into the phosphorus receiving tank 141 in the washing tower.

[0071] Figure 2 This is a schematic diagram of an embodiment of the liquid phosphorus treatment system of the present invention.

[0072] like Figure 2 As shown, the liquid phosphorus treatment system includes a combustion tower 210, a hydration tower 220, an absorption tower 230, a tail gas treatment component, a filter component 251, a reflux mechanism 260, a compressed air pump 211, a secondary air pump 212, a first heat exchanger 223, a first spray mechanism 281, a second spray mechanism 282, a third spray mechanism 283, a venturi tube 222, and a cooling water circulation mechanism.

[0073] The combustion tower 210 is used to oxidize and burn liquid phosphorus to generate P2O5, outputting a first gas. The compressed air pump 211 is used to atomize the liquid phosphorus and input the atomized liquid phosphorus into the combustion tower 210. The compressed air pump 211 uses compressed air to atomize the liquid phosphorus. The secondary air pump 212 is used to input secondary air into the combustion tower 210. Thus, atomizing the liquid phosphorus before oxidizing and burning it with air to generate P2O5 can significantly improve the conversion rate. The feed pipe of the combustion tower 210 is Y-shaped, with a main pipe and two branch pipes. One branch pipe serves as the inlet for compressed air and liquid phosphorus, and the other branch pipe serves as the inlet for secondary air. The mixture is then introduced into the combustion tower 210 after mixing in the main pipe. The liquid phosphorus is preferably produced by pressurizing to generate pressurized phosphorus water, which is then fed into the feed pipe. The liquid phosphorus is preferably, but not limited to, produced by the above-described liquid phosphorus production system.

[0074] The hydration tower 220 is used to hydrate P2O5 in the first gas to generate H3PO4, and outputs a second gas and a first acid solution. The first spray mechanism 281 is used to spray a portion of the first acid solution into the hydration tower 220 as an absorbent. The nozzles of the first spray mechanism 281 are located in the middle and top of the hydration tower 220. The first gas enters from the top of the hydration tower 220, and the second gas exits from the bottom of the hydration tower 220 and then flows into the absorption tower 230 through the riser pipe 221. The diameter of the riser pipe 221 is larger than the inlet pipe diameter of the absorption tower 230, the purpose of which is to reduce the gas flow rate in the riser pipe 221 and allow the absorbed liquid phosphorus to flow back into the hydration tower 220. The third spray mechanism 283 is used to spray a portion of the first acid solution into the riser pipe 221 as an absorbent. Thus, the degree of hydration reaction can be significantly improved. The first heat exchanger 223 is used to cool the first acid solution, thereby spraying the cooled first acid solution onto the hydration tower 220 and the rising pipe 221, which can both recover heat and further enhance the degree of hydration reaction.

[0075] The Venturi tube 222 is located between the rising pipe 221 and the absorption tower 230, and is used to accelerate the gas flow rate in the pipe and cause the liquid phase carried by the gas to condense.

[0076] The cooling water circulating mechanism is used for flowing cooling water in the jacket between the combustion tower 210 and the venturi 222 (the combustion tower 210, the first gas flow pipeline, the hydration tower 220, the riser and the venturi 222 all have jackets), thereby taking away reaction heat and helping to improve conversion rate. The cooling water circulating mechanism comprises a soft water tank 271 and a second heat exchanger 270, hot soft water in the soft water tank 271 is first treated by the second heat exchanger 270 to obtain cooling water, then flows into the jacket to take away reaction heat, and finally flows back into the soft water tank 271 for circulation.

[0077] The absorption tower 230 is used for absorbing P2O5 in the second gas, and outputs third gas and second acid liquid; the second spraying mechanism 282 is used for spraying part of the second acid liquid into the absorption tower 230 for use as an absorbent; and the reflux mechanism 260 is used for flowing part of the second acid liquid into the hydration tower 220 for use as an absorbent; thereby, the second acid liquid with low concentration is reused, high-concentration phosphoric acid can be obtained, and high production efficiency is ensured. With the reflux of the second acid liquid, soft water is input into the absorption tower 230 at a certain rate for use as an absorbent. Two distributors 231 are arranged in the absorption tower 230, and the second spraying mechanism 282 is arranged between the two distributors 231, thereby uniformly distributing the gas entering and leaving the absorption tower 230 and achieving more sufficient absorption.

[0078] The tail gas treatment assembly is used for treating the third gas and discharging tail gas; preferably, the tail gas treatment assembly comprises a demister 241 and a separator 242 which treat the third gas in sequence, thereby realizing two-stage gas-liquid separation to completely remove acid mist brought by the third gas.

[0079] The filtering assembly 251 is used for filtering part of the first acid liquid to remove various solid impurities in system operation, and outputs high-quality finished phosphoric acid; the filtering assembly 251 comprises any one of a plate-and-frame filter, a metal filter element and a ceramic filter element, and the product phosphoric acid is stored in a finished acid tank 252.

[0080] The embodiment of the yellow phosphorus furnace gas treatment system of the application is a liquid phosphorus production system and a liquid phosphorus treatment system as described above, the first heater 111 is connected with an exhaust pipeline of the yellow phosphorus electric furnace 100, the furnace gas enters the first heater 111 under the action of the induced draft fan 150, is temporarily stored in the pressurized phosphorus tank 213 in a pressurized manner (i.e. pressurized phosphorus water) by the liquid phosphorus in the phosphorus tank 141, and then is pressed into the combustion tower 210.

[0081] The embodiment of the phosphoric acid production method of the application adopts the yellow phosphorus furnace gas treatment system as described above.

[0082] The phosphoric acid prepared by the yellow phosphorus furnace gas treatment system and the phosphoric acid production method has a concentration of 85% or more and high purity, no dangerous waste mud phosphorus and phosphogypsum are generated, no harmful chemical waste liquid is generated, tail gas is discharged up to standard, operation cost is low and economic benefit is good, and the economic value of the phosphate rock can be significantly improved, and the environmental protection value is significantly improved.

[0083] The above describes the relevant content of the present application. Those skilled in the art will be able to implement the present application based on these descriptions. Based on the above content of the present application, all other embodiments obtained by those skilled in the art without creative labor shall fall within the scope of protection of the present application.

Claims

1. A liquid phosphorus production system for treating yellow phosphorus furnace gas from a yellow phosphorus furnace (100) and outputting liquid phosphorus, characterized by: The system comprises: a heating device for heating treatment of the furnace gas, and outputting heated gas; a feeding device (120) for inputting conditioning powder into the heated gas, and outputting mixed gas; the conditioning powder comprises inorganic oxide powder for absorbing moisture and acidic components in the heated gas; the conditioning powder comprises CaO powder and SiO2 powder; a filtering device (130) for gas-solid separation treatment of the mixed gas, and outputting clean gas; a condensing device (140) for condensing phosphorus vapor in the clean gas into liquid phosphorus; the heating device comprises a first heater (111) and a second heater (112), and part of particles in the furnace gas naturally settle into an ash tank (113) in the first heater (111); the temperature of the furnace gas is 130-170 ℃; the first heater (111) heats the furnace gas to 170-210 ℃; the second heater (112) heats the furnace gas to 200-240 ℃; and the mass ratio of the CaO powder to the SiO2 powder is (2-4):

1.

2. A yellow phosphorus furnace gas treatment system, characterized by: The system comprises: the liquid phosphorus production system of claim 1; a liquid phosphorus treatment system for reacting the liquid phosphorus to generate finished phosphoric acid.

3. The yellow phosphorus furnace gas treatment system of claim 2, wherein: The liquid phosphorus treatment system comprises: a combustion tower (210) for oxidizing and combusting the liquid phosphorus to generate P2O5, and outputting first gas; a hydration tower (220) for hydrating reaction of the P2O5 to generate H3PO4, and outputting second gas and first acid liquid; an absorption tower (230) for absorbing P2O5 in the second gas, and outputting third gas and second acid liquid; a tail gas treatment assembly for treating the third gas and discharging tail gas; a filtering assembly (251) for filtering part of the first acid liquid and outputting finished phosphoric acid; a reflux mechanism (260) for flowing part of the second acid liquid into the hydration tower (220) to be used as absorbent.

4. The yellow phosphorus furnace gas treatment system of claim 3, wherein: The system further comprises a first spraying mechanism (281) for spraying part of the first acid liquid into the hydration tower (220) to be used as absorbent.

5. The yellow phosphorus furnace gas treatment system of claim 3, wherein: The system further comprises a second spraying mechanism (282) for spraying part of the second acid liquid into the absorption tower (230) to be used as absorbent.

6. A process for the production of phosphoric acid, characterized by: The system adopts the yellow phosphorus furnace gas treatment system of any one of claims 2-5.

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