Sulfuric acid production system based on high-content phosphogypsum-based super-adiabatic porous high-temperature-resistant material

Abstract

The invention belongs to the technical field of ardealite, and provides a sulfuric acid production system based on a high-content ardealite-based super-adiabatic porous high-temperature-resistant material, which comprises a super-adiabatic porous high-temperature-resistant material preparation system, a recovery treatment system and an acid making system, according to the sulfuric acid production system, furnace gas generated in the process of preparing the high-content phosphogypsum-based super-adiabatic porous high-temperature-resistant material is subjected to cooling recovery, electric precipitation, waste heat recovery, cooling and acid pickling in sequence to obtain pretreated furnace gas; and preparing sulfuric acid by using the pretreated furnace gas through a two-conversion and two-absorption contact method. According to the sulfuric acid production system provided by the invention, the dust content of the furnace gas is ultralow while the recovery of high-concentration SO2 is ensured, 80% of impurity components in the furnace gas can be reduced, the maximum concentration of the prepared initial sulfuric acid can reach 22.7%, the new field of phosphogypsum material utilization is widened, and a heat insulation material with ultralow heat conductivity is provided for high-temperature industry. Meanwhile, the impurity removal process and cost of acid making are reduced, and the purity is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of phosphogypsum, and in particular to a sulfuric acid production system based on a high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material. Background Art

[0002] Phosphogypsum is the main by-product in the production of wet-process phosphoric acid. For every ton of phosphoric acid produced, 4 to 5 tons of phosphogypsum are usually produced. With the rapid development of the phosphate fertilizer and phosphorus chemical industries, the annual output of phosphogypsum in the world has increased year by year, and the stockpile of phosphogypsum has increased year by year. This not only occupies a large amount of land resources, but also brings serious environmental problems. Phosphogypsum contains a small amount of impurities such as soluble phosphorus, fluoride and heavy metals. If it is stored for a long time, it will not only pollute the soil and water sources, but also may cause dust pollution and potential radioactive threats. Therefore, how to efficiently treat and recycle phosphogypsum has become a topic that needs to be urgently solved in the current field of environmental protection and resource utilization.

[0003] Although the main component of phosphogypsum is calcium sulfate dihydrate (CaSO4·2H2O), it theoretically has a high utilization potential. However, in practical applications, due to its high impurity content and unstable properties, its dosage in building materials, soil conditioners and other fields is not high, and its large-scale utilization is limited. In addition, the large-scale utilization of phosphogypsum also faces the technical difficulty of impurity removal. Therefore, promoting the research on the high value and large-scale utilization of phosphogypsum is not only of great significance to the recycling of resources, but also can effectively alleviate the ecological and environmental threats caused by its storage.

[0004] In recent years, the comprehensive utilization of phosphogypsum has received extensive attention at home and abroad, among which the use of it to produce building materials such as lightweight wallboards, insulation boards, and cementitious materials has gradually become a research hotspot. However, due to the presence of impurities in phosphogypsum, these applications often require complex pretreatment processes, which increases production costs. At the same time, in the chemical industry, research on the use of phosphogypsum to co-produce sulfuric acid and other high-value-added products has also gradually emerged, which provides new possibilities for the resource utilization of phosphogypsum.

[0005] A phosphogypsum-coal gangue-based lightweight heat-insulating and high-temperature resistant material and its preparation method CN116621562B, the invention uses all solid waste as raw materials to prepare lightweight heat-insulating and high-temperature resistant materials and its preparation method, realizing the high-value utilization of bulk solid waste. The problem of resource utilization of phosphogypsum is the biggest problem of all solid wastes. The amount of phosphogypsum doping is small, and the effect of large-scale utilization is small; at the same time, during high-temperature calcination, the exhaust gas generated by calcination is not collected for secondary recycling, which wastes SO2 gas resources;

[0006] A production method for producing cement and sulfuric acid from phosphogypsum CN112694067A provides a coupled production method for producing cement and sulfuric acid from phosphogypsum, which uses mechanical dehydration and does not need to be dried separately to remove free water in the phosphogypsum. This invention saves drying fuel, reduces the amount of reducing coal and burned coal, and improves the product quality of cement clinker, achieving energy conservation, reducing the amount of reducing coal and burned coal, and improving the product quality of cement clinker. However, it uses a water washing method to remove impurities from phosphogypsum, which can achieve a certain impurity removal effect, but correspondingly produces a large amount of sewage, which will cause secondary pollution.

[0007] A separate dual system and production method for preparing sulfuric acid and cement from phosphogypsum CN114772559A, to a certain extent, solves the technical problems of poor universality of phosphogypsum, great difficulty in production control, and low SO2 content in acid-making flue gas in the existing technology of acid-making and cement-making process outside the kiln. However, this technology has the following problems. First, the increase in production process lines leads to complex processes and excessively high investment costs for equipment; second, the heat loss is serious, which is not conducive to energy-saving production.

[0008] The device and method for co-producing sulfuric acid by using high-temperature liquid blast furnace slag to produce cement with phosphogypsum / desulfurized gypsum CN114014565A realizes the high-value and efficient resource utilization of blast furnace slag, phosphogypsum and desulfurized gypsum. However, this technology is difficult to control the weak reducing atmosphere, including 3% to 5% CO, 25% to 35% CO2, and a volume ratio of 0.5 to 2.0 carbon and sulfur. The production conditions may affect the uniformity of the reaction process and the quality of the product.

[0009] A method and device for producing sulfuric acid and cement clinker by oxygen-enriched calcination of phosphogypsum CN115432670A provides a sulfuric acid production system and production process based on the phosphogypsum furnace method to solve the technical defects of low calcium sulfate decomposition rate, low sulfur dioxide concentration, and excessive energy consumption in the production of sulfuric acid using phosphogypsum. Improvements have been made in the calcium sulfate decomposition rate and sulfur dioxide concentration, but the invention will take away the temperature of the furnace gas through the primary and secondary air, and at the same time increase the content of dust particles in the furnace gas. In addition, due to the large temperature difference between the ventilation temperature and the temperature in the furnace, the life of the furnace lining refractory material will be greatly reduced. It completely isolates the reduction zone and the oxidation zone to ensure that the combustion reduction reaction of the phosphogypsum can be carried out in an independent reduction zone, which makes the process complicated and difficult to control. Summary of the invention

[0010] The purpose of the present invention is to overcome the defects in the prior art and provide a sulfuric acid production system based on a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material.

[0011] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0012] The present invention provides a sulfuric acid production system based on a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material, comprising a super-insulating porous high-temperature resistant material preparation system, a recovery and processing system, and an acid production system.

[0013] Preferably, the super-insulating porous high-temperature resistant material preparation system includes an industrial kiln 1, a first gate 3, a second gate 4, a condensing device 5, and an exhaust fan 6.

[0014] Preferably, a gas outlet channel is provided on the top of the industrial kiln 1 , the industrial kiln 1 is connected to the exhaust fan 6 through an exhaust pipe, the exhaust pipe is provided with a first gate 3 and a second gate 4 , and the condensing device 5 is connected to the exhaust fan 6 .

[0015] Preferably, the recycling system includes a dust removal device 9, a washing device 10 and a drying device 11.

[0016] Preferably, the exhaust fan 6 is connected to the dust removal device 9 , the washing device 10 is connected to the dust removal device 9 , and the drying device 11 is connected to the washing device 10 .

[0017] Preferably, the acid production system includes a conversion tower 12 , a heat conversion device 13 , a fuming sulfuric acid absorption tower 14 , and a concentrated sulfuric acid absorption tower 15 .

[0018] Preferably, the conversion tower 12 is connected to the drying device 11 , and the conversion tower 12 is connected to the heat conversion device 13 ; the conversion tower 12 is connected to the oleum absorption tower 14 , and the oleum absorption tower 14 is connected to the concentrated sulfuric acid absorption tower 15 .

[0019] The present invention provides a sulfuric acid production system based on a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material, comprising a super-insulating porous high-temperature resistant material preparation system, a recovery and treatment system, and an acid-making system. The super-insulating porous high-temperature resistant material preparation system comprises an industrial kiln, a first gate, a second gate, a condensing device, and an exhaust fan; the recovery and treatment system comprises a dust removal device, a washing device, and a drying device; the acid-making system comprises a conversion tower, a heat conversion device, a fuming sulfuric acid absorption tower, and a concentrated sulfuric acid absorption tower. Through the sulfuric acid production system, the present invention sequentially cools and recovers the furnace gas generated in the process of preparing a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material, electrostatically precipitates, recovers waste heat, cools, and acid-washes to obtain pre-treated furnace gas; and uses the pre-treated furnace gas to prepare sulfuric acid by a two-transformation and two-absorption contact method. The sulfuric acid production system provided by the present invention ensures the recovery of high-concentration SO2 while having ultra-low dust content in the furnace gas, which can reduce 80% of the impurity components in the furnace gas. The initial sulfuric acid concentration prepared can reach up to 22.7%, which broadens the new field of phosphogypsum material utilization and provides ultra-low thermal conductivity insulation materials for high-temperature industries. At the same time, it reduces the impurity removal process and cost of acid production and greatly improves the purity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of a sulfuric acid production system based on a high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material according to the present invention;

[0021] Among them, 1 is an industrial kiln, 2 is a furnace, 3 is a first gate, 4 is a second gate, 5 is a condensing device, 6 is an exhaust fan, 7 is a gas concentration detector, 8 is a temperature detector, 9 is a dust removal device, 10 is a washing device, 11 is a drying device, 12 is a conversion tower, 13 is a heat conversion device, 14 is a fuming sulfuric acid absorption tower, 15 is a concentrated sulfuric acid absorption tower, 16 is a first circulating acid storage tank, 17 is a second circulating acid storage tank, 18 is a deacidification tank, 19 is a stratified atomization device, and 20 is a sensor. DETAILED DESCRIPTION

[0022] The present invention provides a sulfuric acid production system based on a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material, comprising a super-insulating porous high-temperature resistant material preparation system, a recovery and processing system, and an acid production system.

[0023] The present invention also provides a high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material, which is prepared from raw materials containing the following parts by mass:

[0024] Phosphogypsum A 30-45 parts;

[0025] Phosphogypsum B 30-45 parts;

[0026] 5-16 parts of fly ash;

[0027] Rice husk ash 0-10 parts;

[0028] 0-5 parts of shrimp shell powder;

[0029] Binder 0-13 parts;

[0030] 4-15 parts water;

[0031] The particle size of the phosphogypsum A is less than 30 μm, and the particle size of the phosphogypsum B is in the range of 30 to 75 μm;

[0032] The contents of the rice husk ash, shrimp shell powder and binder are not all 0 at the same time.

[0033] In the present invention, the content of the phosphogypsum A is preferably 35 to 40 parts by mass, and more preferably 40 parts by mass.

[0034] In the present invention, the content of the phosphogypsum B is preferably 35 to 40 parts by mass, and more preferably 40 parts by mass.

[0035] In the present invention, the content of the fly ash is preferably 8 to 12 parts by mass, and more preferably 10 parts by mass.

[0036] In the present invention, the content of the rice husk ash is preferably 2 to 9 parts by mass, and more preferably 5 to 8 parts by mass.

[0037] In the present invention, the content of the binder is preferably 3 to 9 parts by mass, and more preferably 4 to 7 parts by mass.

[0038] In the present invention, the content of water is preferably 8 to 12 parts by mass, and more preferably 10 parts by mass.

[0039] In the present invention, the particle size of the fly ash is preferably ≤75μm, the C content in the fly ash is 6-12wt%, preferably 8-10wt%; the Al2O3 content is 25-45wt%, preferably 30-40wt%; the SiO2 content is 40-60wt%, preferably 45-55wt%.

[0040] In the present invention, the CaSO4 content in the phosphogypsum A and the phosphogypsum B is 75-95wt%, preferably 80-90wt%, and more preferably 85wt%.

[0041] In the present invention, the particle size of the rice husk ash is preferably ≤2 μm, and the content of SiO2 in the rice husk ash is ≥70wt%.

[0042] In the present invention, the binder is preferably phosphogypsum treated at a high temperature of 200°C.

[0043] In the present invention, the particle size of the shrimp shell powder is preferably ≤30 μm.

[0044] The present invention provides a method for preparing a high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material, comprising the following steps:

[0045] (1) mixing phosphogypsum A, phosphogypsum B, fly ash, rice husk ash and shrimp shell powder to obtain an initial mixture;

[0046] (2) mixing the initial mixture, the binder and water to obtain a mixture;

[0047] (3) pressing the mixed material into a shape and drying it to obtain an initial green body;

[0048] (4) The initial green body is subjected to programmed temperature calcination to obtain a high-doped phosphogypsum-based ultra-insulating porous high-temperature resistant material.

[0049] In the present invention, the time of trapping the material is 0.5 to 5 hours, preferably 2 to 4 hours; the pressure of pressing is 5 to 8 MPa, preferably 6 MPa; the temperature of drying is 60 to 110° C., preferably 90 to 100° C.; the time of drying is 18 to 36 hours, preferably 24 hours.

[0050] In the present invention, the programmed temperature calcination specifically comprises: heating the initial green body from 20 to 30 ° C to 300 ° C at a rate of 1 to 2 ° C / min, heating from 300 ° C to 800 to 1000 ° C at a rate of 2 to 5 ° C / min, and then heating to 1100 to 1400 ° C at a rate of 5 to 8 ° C / min, and keeping warm for 2 to 5 hours; preferably, the initial green body is first heated from 25 ° C to 300 ° C at a rate of 1 ° C / min, heated from 300 ° C to 900 ° C at a rate of 3 ° C / min, and then heated to 1200 ° C at a rate of 8 ° C / min, and kept warm for 4 hours.

[0051] In the present invention, in step (1) and step (2), the mixing is carried out under stirring until the mixture is uniform.

[0052] In the present invention, the initial green body is placed in the furnace 2 of the industrial kiln 1 for programmed temperature calcination, so that sulfuric acid can be produced while obtaining a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material.

[0053] In the present invention, the super-insulating porous high-temperature resistant material preparation system includes an industrial kiln 1, a first gate 3, a second gate 4, a condensing device 5, and an exhaust fan 6.

[0054] In the present invention, the internal refractory layer of the industrial kiln 1 is coated with a high temperature and corrosion resistant layer, the hot end inside the furnace is densely filled with refractory cement in the furnace lining gaps, the outside of the refractory material is filled with high-density refractory wool, and the outside of the furnace lining is sealed with a thickened steel plate to seal the entire furnace body.

[0055] In the present invention, a gas outlet channel is arranged on the top of the industrial kiln 1, and an exhaust pipe is arranged in the gas outlet channel for conveying the gas generated in the industrial kiln 1. A condensing device 5 is arranged at the port of the gas outlet channel so that the gas can be cooled in the initial stage of being discharged from the industrial kiln 1. The industrial kiln 1 is connected to the exhaust fan 6 through the exhaust pipe.

[0056] In the present invention, the initial end of the exhaust pipe is provided with a first gate 3 and a second gate 4 through a tee. Sensors are provided at the gates to detect the SO2 gas concentration and temperature. When the temperature is lower than 200°C, the gas mainly discharged is water vapor, and when the temperature is 200-300°C, it is mainly part of the impurity gas. At this time, the air is directly discharged from the first gate 3. At 300°C, the gas begins to be collected and discharged from the second gate 4. The switches of the first gate 3 and the second gate 4 are set as automatic switches and are connected to the kiln program. When the kiln program is heated to 300°C, the first gate 3 is automatically closed and the second gate 4 is opened for gas recovery and treatment. At this time, the SO2 gas content is relatively high, and the furnace gas is subsequently treated through the exhaust pipe.

[0057] In the present invention, the condensing device 5 is connected to the exhaust fan 6 .

[0058] In the present invention, the exhaust fan 6 is provided with a gas concentration detector 7 and a temperature detector 8 for detecting the physical properties of the gas.

[0059] In the present invention, the recycling system includes a dust removal device 9, a washing device 10 and a drying device 11.

[0060] In the present invention, the exhaust fan 6 is connected to the dust removal device 9 , the washing device 10 is connected to the dust removal device 9 , and the drying device 11 is connected to the washing device 10 .

[0061] In the present invention, the gas delivered by the exhaust fan 6 enters the dust removal device 9, where fine dust is removed by electrostatic dust removal; then the gas is delivered to the washing device 10, where the impurities in the gas are removed by acid washing; the gas after acid washing is dried by the drying device 11, and the gas is dried by concentrated sulfuric acid. The drying rate can be increased by increasing the contact area. The gas contacts from bottom to top and the concentrated sulfuric acid contacts from top to bottom in countercurrent, so as to obtain a relatively pure SO2 gas.

[0062] In the present invention, the drying device 11 comprises a layered atomization device 19, which atomizes the concentrated sulfuric acid in batches to increase the contact area and contact times between the concentrated sulfuric acid and the gas, thereby improving the drying efficiency.

[0063] In the present invention, the acid production system includes a conversion tower 12 , a heat conversion device 13 , an oleum absorption tower 14 , and a concentrated sulfuric acid absorption tower 15 .

[0064] In the present invention, the conversion tower 12 is connected to the drying device 11, and the relatively pure SO2 gas transported from the drying device 11 is converted into SO3 in the conversion tower 12 with oxygen.

[0065] In the present invention, the conversion tower 12 is provided with multiple conversion layers, and the multiple conversion layers are connected to the heat conversion device 13 .

[0066] In the present invention, the heat conversion device 13 is a tubular heat exchanger, which disperses the heat to increase the contact area and improve the heat exchange rate.

[0067] In the present invention, the conversion tower 12 is connected to the oleum absorption tower 14 , and the SO 3 generated in the conversion tower 12 enters the oleum absorption tower 14 .

[0068] In the present invention, a sensor 20 is provided between the conversion tower 12 and the oleum absorption tower 14 for detecting the concentrations of SO2, SO3, and O2 in the furnace gas at this time to verify the conversion rate of SO2 to SO3.

[0069] In the present invention, SO3 is in the oleum absorption tower 14 in a gas-liquid countercurrent contact mode, with gas entering from the bottom of the tower and concentrated sulfuric acid spraying from the top of the tower, and the two are in countercurrent contact. The driving force for mass transfer is increased by increasing the gas-liquid temperature difference, and the temperature of the sulfuric acid out of the tower is controlled by the spraying amount, so that the temperature of the sulfuric acid out of the tower is less than 60°C, which is convenient for transportation and storage.

[0070] In the present invention, the oleum absorption tower 14 is connected to the concentrated sulfuric acid absorption tower 15, and the sulfuric acid generated in the oleum absorption tower 14 enters the concentrated sulfuric acid absorption tower 15 for subsequent treatment.

[0071] In the present invention, the acid production system further includes a first circulating acid storage tank 16, a second circulating acid storage tank 17 and an acid removal tank 18 for transporting and storing sulfuric acid.

[0072] The schematic diagram of the sulfuric acid production system based on high-doped phosphogypsum-based super-insulating porous high-temperature resistant material in the present invention is as follows Figure 1 shown.

[0073] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0074] Example 1

[0075] (1) firstly add 30 parts of phosphogypsum A (particle size ≤ 30 μm), 45 parts of phosphogypsum B (30 μm ≤ particle size ≤ 75 μm), 10 parts of fly ash (particle size ≤ 2 μm, 12 wt% ≥ C content ≥ 6 wt%), 10 parts of rice husk ash (particle size ≤ 2 μm) and 5 parts of shrimp shell powder (particle size ≤ 30 μm), stir evenly to obtain an initial mixture; then add 4 parts of deionized water, stir evenly to obtain a mixture;

[0076] (2) trapping the mixture for 2 hours, pressing and molding, and drying at 110° C. for 24 hours to obtain an initial green body;

[0077] (3) The initial green body is first heated from room temperature to 300°C at a rate of 1°C / min, then heated to 800°C at a rate of 2°C / min, and then heated to 1100°C at a rate of 5°C / min, kept warm for 2 hours, and furnace cooled to room temperature to obtain a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material.

[0078] 50m 3 The initial blank is placed in the furnace of an industrial kiln for calcination. When the temperature of the furnace is lower than 300°C, the furnace gas is discharged through the first gate. When the temperature is higher than 300°C, the furnace gas is discharged through the second gate. Then, it is cooled by a condensing device and exhausted by an exhaust fan. The gas concentration and temperature are detected by a gas concentration detector and a temperature detector respectively. Then, the dust removal device is used to remove dust to obtain a relatively pure furnace gas, which is then passed into a washing device for pickling, and then passed into a drying device for drying. Then, it is passed into a conversion tower to convert pure SO2 into SO3. During the conversion process, the heat conversion device is used for cooling treatment, and SO3 is passed into a fuming sulfuric acid absorption tower. The gas-liquid reverse contact method is adopted, and the conversion gas enters from the bottom of the tower, and concentrated sulfuric acid is sprayed from the top of the tower, and the two are in countercurrent contact. The temperature of the gas entering the tower is about 140°C. The temperature of the sprayed sulfuric acid is controlled at below 40°C. The driving force for mass transfer is increased by increasing the temperature difference between gas and liquid, so that the temperature of the sulfuric acid out of the tower is less than 80°C. It is initially obtained that 49.8m 3 Super-insulating porous high-temperature resistant material and 15% concentration of sulfuric acid; then passed into the concentrated sulfuric acid absorption tower for further absorption and concentration, temporarily stored in the first circulation acid storage tank and the second circulation acid storage tank, and the prepared acid is transported through the deacidification tank.

[0079] Example 2

[0080] (1) firstly add 35 parts of phosphogypsum A (particle size ≤ 30 μm), 40 parts of phosphogypsum B (30 μm ≤ particle size ≤ 75 μm), 14 parts of fly ash (particle size ≤ 2 μm, 12 wt% ≥ C content ≥ 6 wt%), 9 parts of rice husk ash (particle size ≤ 2 μm) and 4 parts of shrimp shell powder (particle size ≤ 30 μm), stir evenly to obtain an initial mixture; then add 3 parts of a binder and 4 parts of deionized water, stir evenly to obtain a mixture;

[0081] (2) trapping the mixture for 2 hours, pressing and molding, and drying at 110° C. for 24 hours to obtain an initial green body;

[0082] (3) The initial green body is first heated from room temperature to 300°C at a rate of 1°C / min, then heated to 900°C at a rate of 3°C / min, and then heated to 1200°C at a rate of 6°C / min, kept warm for 2 hours, and furnace cooled to room temperature to obtain a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material.

[0083] 75m 3The initial blank is placed in the furnace of an industrial kiln for calcination. When the temperature of the furnace is lower than 300°C, the furnace gas is discharged through the first gate. When the temperature is higher than 300°C, the furnace gas is discharged through the second gate. Then, it is cooled by a condensing device and exhausted by an exhaust fan. The gas concentration and temperature are detected by a gas concentration detector and a temperature detector respectively. Then, the dust is removed by a dust removal device to obtain a relatively pure furnace gas, which is then passed into a washing device for pickling, and then passed into a drying device for drying. Then, it is passed into a conversion tower to convert pure SO2 into SO3. During the conversion process, the temperature is reduced by a heat conversion device, and SO3 is passed into a fuming sulfuric acid absorption tower. The gas-liquid reverse contact method is adopted, and the conversion gas enters from the bottom of the tower, and concentrated sulfuric acid is sprayed from the top of the tower, and the two are in countercurrent contact. The temperature of the gas entering the tower is about 140°C. The temperature of the sprayed sulfuric acid is controlled at below 40°C. The driving force for mass transfer is increased by increasing the gas-liquid temperature difference, so that the temperature of the sulfuric acid out of the tower is less than 80°C. It is initially obtained that 73.8m 3 Super-insulating porous high-temperature resistant material and 18% concentration of sulfuric acid; then passed into the concentrated sulfuric acid absorption tower for further absorption and concentration, temporarily stored in the first circulation acid storage tank and the second circulation acid storage tank, and the prepared acid is transported through the deacidification tank.

[0084] Example 3

[0085] (1) firstly add 40 parts of phosphogypsum A (particle size ≤ 30 μm), 35 parts of phosphogypsum B (30 μm ≤ particle size ≤ 75 μm), 14 parts of fly ash (particle size ≤ 2 μm, 12 wt% ≥ C content ≥ 6 wt%), 8 parts of rice husk ash (particle size ≤ 2 μm) and 4 parts of shrimp shell powder (particle size ≤ 30 μm), stir evenly to obtain an initial mixture; then add 4 parts of a binder and 4 parts of deionized water, stir evenly to obtain a mixture;

[0086] (2) The mixed material is trapped for 2 hours, pressed into a shape, and dried at 100° C. for 24 hours to obtain an initial green body;

[0087] (3) The initial green body is first heated from room temperature to 300°C at a rate of 2°C / min, then heated to 1000°C at a rate of 4°C / min, and then heated to 1300°C at a rate of 6°C / min, kept warm for 2 hours, and furnace cooled to room temperature to obtain a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material.

[0088] 100m 3The initial blank is placed in the furnace of an industrial kiln for calcination. When the temperature of the furnace is lower than 300°C, the furnace gas is discharged through the first gate. When the temperature is higher than 300°C, the furnace gas is discharged through the second gate. Then, it is cooled by a condensing device and exhausted by an exhaust fan. The gas concentration and temperature are detected by a gas concentration detector and a temperature detector respectively. Then, the dust removal device is used to remove dust to obtain a relatively pure furnace gas, which is then passed into a washing device for pickling, and then passed into a drying device for drying. Then, it is passed into a conversion tower to convert pure SO2 into SO3. During the conversion process, the heat conversion device is used for cooling treatment, and SO3 is passed into a fuming sulfuric acid absorption tower. The gas-liquid reverse contact method is adopted, and the conversion gas enters from the bottom of the tower, and concentrated sulfuric acid is sprayed from the top of the tower, and the two are in countercurrent contact. The temperature of the gas entering the tower is about 140°C. The temperature of the sprayed sulfuric acid is controlled at below 40°C. The driving force for mass transfer is increased by increasing the temperature difference between gas and liquid, so that the temperature of the sulfuric acid out of the tower is less than 80°C. Preliminary results show that 96.2m 3 Super-insulating porous high-temperature resistant material and 20% concentration of sulfuric acid; then pass into the concentrated sulfuric acid absorption tower for further absorption and concentration, temporarily stored in the first circulation acid storage tank and the second circulation acid storage tank, and the prepared acid is transported through the deacidification tank.

[0089] Example 4

[0090] (1) firstly add 40 parts of phosphogypsum A (particle size ≤ 30 μm), 35 parts of phosphogypsum B (30 μm ≤ particle size ≤ 75 μm), 15 parts of fly ash (particle size ≤ 2 μm, 12 wt% ≥ C content ≥ 6 wt%), 6 parts of rice husk ash (particle size ≤ 2 μm) and 2 parts of shrimp shell powder (particle size ≤ 30 μm), stir evenly to obtain an initial mixture; then add 7 parts of a binder and 8 parts of deionized water, stir evenly to obtain a mixture;

[0091] (2) trapping the mixture for 3 hours, pressing and molding, and drying at 100° C. for 24 hours to obtain an initial green body;

[0092] (3) The initial green body is first heated from room temperature to 300°C at a rate of 2°C / min, then heated to 900°C at a rate of 4°C / min, and then heated to 1400°C at a rate of 5°C / min, kept warm for 3 hours, and furnace cooled to room temperature to obtain a high-doped phosphogypsum-based super-insulating porous high-temperature resistant material.

[0093] 125m 3The initial blank is placed in the furnace of an industrial kiln for calcination. When the temperature of the furnace is lower than 300°C, the furnace gas is discharged through the first gate. When the temperature is higher than 300°C, the furnace gas is discharged through the second gate. Then, it is cooled by a condensing device and exhausted by an exhaust fan. The gas concentration and temperature are detected by a gas concentration detector and a temperature detector respectively. Then, the dust removal device is used to remove dust to obtain a relatively pure furnace gas, which is then passed into a washing device for pickling, and then passed into a drying device for drying. Then, it is passed into a conversion tower to convert pure SO2 into SO3. During the conversion process, the heat conversion device is used for cooling treatment, and SO3 is passed into a fuming sulfuric acid absorption tower. The gas-liquid reverse contact method is adopted, and the conversion gas enters from the bottom of the tower, and concentrated sulfuric acid is sprayed from the top of the tower, and the two are in countercurrent contact. The temperature of the gas entering the tower is about 140°C. The temperature of the sprayed sulfuric acid is controlled at below 40°C. The driving force for mass transfer is increased by increasing the gas-liquid temperature difference, so that the temperature of the sulfuric acid out of the tower is less than 80°C. Preliminary results show that 119.3m 3 Super-insulating porous high-temperature resistant material and 22.7% concentration of sulfuric acid; then passed into the concentrated sulfuric acid absorption tower for further absorption and concentration, temporarily stored in the first circulation acid storage tank and the second circulation acid storage tank, and the prepared acid is transported through the deacidification tank.

[0094] It can be seen from the above embodiments that the present invention provides a sulfuric acid production system based on high-doped phosphogypsum-based super-insulating porous high-temperature resistant materials, including a super-insulating porous high-temperature resistant material preparation system, a recovery and processing system, and an acid production system. Sulfuric acid can be co-produced while producing high-temperature resistant materials, and the furnace gas generated during the calcination process is recovered to prepare sulfuric acid. There is no need to adopt a separate dual-system production, which saves equipment investment. The concentration of the co-produced sulfuric acid is 15-23%, which maximizes the high value and resource utilization of phosphogypsum.

[0095] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A sulfuric acid production system based on high-doped phosphogypsum-based super-insulating porous high-temperature resistant materials, characterized in that: It includes a super-insulating porous high-temperature resistant material preparation system, a recycling and processing system, and an acid production system.

2. The sulfuric acid production system based on high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material according to claim 1, characterized in that: The super-insulating porous high-temperature resistant material preparation system comprises an industrial kiln (1), a first gate (3), a second gate (4), a condensing device (5), and an exhaust fan (6).

3. The sulfuric acid production system based on high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material according to claim 2, characterized in that: A gas outlet channel is arranged at the top of the industrial kiln (1); the industrial kiln (1) is connected to an exhaust fan (6) via an exhaust pipe; the exhaust pipe is provided with a first gate (3) and a second gate (4); and a condensing device (5) is connected to the exhaust fan (6).

4. The sulfuric acid production system based on high-doped phosphogypsum-based super-insulating porous high-temperature resistant material according to any one of claims 1 to 3, characterized in that: The recycling system comprises a dust removal device (9), a washing device (10) and a drying device (11).

5. The sulfuric acid production system based on high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material according to claim 4, characterized in that: The exhaust fan (6) is connected to the dust removal device (9), the washing device (10) is connected to the dust removal device (9), and the drying device (11) is connected to the washing device (10).

6. The sulfuric acid production system based on high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material according to claim 1 or 5, characterized in that: The acid production system comprises a conversion tower (12), a heat conversion device (13), a fuming sulfuric acid absorption tower (14), and a concentrated sulfuric acid absorption tower (15).

7. The sulfuric acid production system based on high-dosage phosphogypsum-based super-insulating porous high-temperature resistant material according to claim 6, characterized in that: The conversion tower (12) is connected to a drying device (11), and the conversion tower (12) is connected to a heat conversion device (13); the conversion tower (12) is connected to an oleum absorption tower (14), and the oleum absorption tower (14) is connected to a concentrated sulfuric acid absorption tower (15).

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