A fluidized bed based sodium fluosilicate and cryolite synergistic recovery device

Abstract

The utility model provides a kind of sodium fluorosilicate and cryolite collaborative recovery device based on fluidized bed, the recovery device includes reactor body;From the direction perpendicular to ground upward, the reactor body includes water distribution unit, sodium fluorosilicate crystallization unit and cryolite crystallization unit.The utility model can simultaneously recover sodium fluorosilicate and cryolite by setting layered structure, realizes the staged recovery of fluorine resource, effectively reduces the energy consumption of fluorine resource recovery;And the structure of the recovery device is simple, easy to operate, conducive to industrial application.

Description

Technical Field

[0001] This utility model belongs to the field of fluoride recovery and treatment technology in fluoride-containing wastewater, and particularly relates to a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. Background Technology

[0002] Fluorides are a non-renewable mineral resource with uneven global distribution. Although China has large reserves, long-term mining could lead to resource depletion. Secondly, improper handling of fluorides can cause serious environmental pollution. For example, hydrogen fluoride gas is toxic, fluoride-containing wastewater pollutes water bodies, affects plant and animal growth, and can even harm human health through the food chain. Furthermore, fluoride recycling can promote a circular economy, reduce production costs, and decrease dependence on primary resources, aligning with sustainable development requirements. Currently, the most widely used fluoride recycling technology is the recovery technology for calcium fluoride (fluorite), which has relatively simple chemical reactions and low reaction condition requirements. However, there are fewer technologies for the recovery of sodium fluorosilicate and cryolite.

[0003] Wastewater from optoelectronic companies (such as photovoltaic glass and LED chip manufacturing) contains high concentrations of fluoride ions (F). - ), silicates (SiO3) 2- ) and aluminum ions (Al 3+ Traditional treatment processes (such as chemical precipitation) have many drawbacks: First, fluorosilicates and aluminum salts are prone to co-precipitation, resulting in low purity of the treated products, which is difficult to meet the high-quality requirements for resource recycling; second, the precipitated sludge produced during the treatment process has an excessively high water content, requiring a large amount of energy for subsequent separation and treatment, thus increasing treatment costs; third, traditional processes cannot achieve graded recovery of fluorine, silicon, and aluminum resources, resulting in resource waste and hindering the development of a circular economy.

[0004] Therefore, there is an urgent need to develop a technology that can effectively solve the above problems and achieve simultaneous graded recovery of sodium fluorosilicate and cryolite. Utility Model Content

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a fluidized bed-based co-recovery device for sodium fluorosilicate and cryolite. This invention, through a layered structure, can simultaneously recover sodium fluorosilicate and cryolite, achieving graded recovery of fluorine resources and effectively reducing energy consumption in fluorine resource recovery. Furthermore, the recovery device has a simple structure, is easy to operate, and is conducive to industrial application.

[0006] To achieve this objective, the present invention adopts the following technical solution: This invention provides a fluidized bed-based device for the synergistic recovery of sodium fluorosilicate and cryolite, the recovery device comprising a reactor body; The reactor body includes a water distribution unit, a sodium fluorosilicate crystallization unit, and a cryolite crystallization unit, which are located in the direction perpendicular to the ground and pointing upwards.

[0007] The wastewater treated by this invention is wastewater from an optoelectronic enterprise, and its main component is fluoride ions (F). - ), silicates (SiO3) 2- ) and aluminum ions (Al 3+ This invention achieves the recovery of fluoride and silicate ions in the sodium fluorosilicate crystallization unit and the recovery of fluoride and aluminum ions in the cryolite crystallization unit by setting a layered structure. The recycling device provided by this utility model realizes the graded recycling of fluorine resources and effectively reduces the energy consumption of fluorine resource recycling.

[0008] As a preferred embodiment of this invention, the water distribution unit, the sodium fluorosilicate crystallization unit, and the cryolite crystallization unit are connected by a filtration device.

[0009] The sidewalls of the water distribution unit, sodium fluorosilicate crystallization unit, and cryolite crystallization unit are each independently provided with a manhole-observation hole.

[0010] In this invention, the manhole-observation hole in the water distribution unit is used to observe the size of the seed crystals and the overall height of the crystals in the fluidized bed, and to determine whether crystal removal is necessary; the manhole-observation hole on the side wall of the sodium fluorosilicate crystallization unit and the cryolite crystallization unit is used to observe the grain size, and to obtain sodium fluorosilicate grains and cryolite grains.

[0011] As a preferred technical solution of this utility model, the height of the water distribution unit is 12~13m, for example, it can be 12m, 12.2m, 12.4m, 12.6m, 12.8m or 13m, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0012] Preferably, a drain pipe is provided at the bottom end of the side wall of the water distribution unit.

[0013] Preferably, a fluoride-containing wastewater inlet pipe is provided at the top of the side wall of the water distribution unit.

[0014] Preferably, the side wall of the water distribution unit is provided with a circulating water inlet pipe.

[0015] Preferably, the vertical height of the fluoride-containing wastewater inlet pipe and the circulating water inlet pipe is 0.5~1.0m, for example, it can be 0.5m, 0.6m, 0.7m, 0.8m, 0.9m or 1.0m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0016] As a preferred technical solution of this utility model, the height of the sodium fluorosilicate crystallization unit is 4~5m, for example, it can be 4m, 4.2m, 4.4m, 4.6m, 4.8m or 5m, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] Preferably, the bottom end of the sidewall of the sodium fluorosilicate crystallization unit is provided with a first row of crystal openings.

[0018] Preferably, the sidewall of the sodium fluorosilicate crystallization unit is provided with a first temperature control and dosing device.

[0019] Preferably, the vertical distance between the first temperature control and dosing device and the first crystal outlet is 0.3~0.8m, for example, it can be 0.3m, 0.4m, 0.4m, 0.5m, 0.6m, 0.7m or 0.8m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0020] It is worth noting that the purpose of the first temperature control and dosing device includes: (1) controlling the temperature in the sodium fluorosilicate crystallization unit to 40~60℃; (2) adding acid-base regulators to make the pH value of the system 2~4; (3) adding sodium element to ensure the crystallization of sodium fluorosilicate.

[0021] As a preferred technical solution of this utility model, the height of the cryolite crystallization unit is 6~7m, for example, it can be 6m, 6.2m, 6.4m, 6.6m, 6.8m or 7m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, a second row of crystal openings is provided at the bottom end of the sidewall of the cryolite crystallization unit.

[0023] Preferably, the cryolite crystallization unit is provided with a second temperature control and dosing device on its sidewall.

[0024] Preferably, the distance between the second temperature control and dosing device and the second crystal outlet is 0.3~0.8m, for example, it can be 0.3m, 0.4m, 0.4m, 0.5m, 0.6m, 0.7m or 0.8m, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] It is worth noting that the second temperature control and dosing device has the following uses: (1) controlling the temperature in the cryolite crystallization unit to 70~80℃; (2) adding acid-base regulators to make the pH value of the system 5~6; (3) adding aluminum to ensure the crystallization of cryolite (Na3AlF6).

[0026] As a preferred technical solution of this utility model, the top of the side wall of the cryolite crystallization unit is provided with a circulating water outlet pipe and a wastewater outlet pipe.

[0027] Preferably, the cryolite crystallization unit is equipped with a circulating water storage tank and a wastewater storage tank.

[0028] Preferably, the circulating water storage tank is connected to the circulating water outlet pipe, and the wastewater storage tank is connected to the wastewater outlet pipe.

[0029] As a preferred technical solution of this utility model, the distance between the overflow weir of the circulating water storage tank and the top of the cryolite crystallization unit is 1200~1600mm, for example, it can be 1200mm, 1300mm, 1400mm, 1500mm or 1600mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, the distance between the overflow weir of the wastewater storage tank and the top of the cryolite crystallization unit is 1200~1800mm, for example, it can be 1200mm, 1400mm, 1600mm or 1800mm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] It is worth noting that the distance between the overflow weir of the circulating water storage tank and the top of the cryolite crystallization unit in this utility model is smaller than the distance between the overflow weir of the wastewater storage tank and the top of the cryolite crystallization unit.

[0032] As a preferred embodiment of this utility model, the circulating water outlet pipe is connected to the circulating water inlet pipe.

[0033] As a preferred technical solution of this utility model, the filtration device, from the direction away from the inlet pipe of fluoride-containing wastewater, includes a filter plate, a filter and a filter screen arranged in sequence.

[0034] Preferably, a check plate is provided at the end of the filter near the filter screen.

[0035] As a preferred technical solution of this utility model, the average pore size of the filter plate is 30~40mm, for example, it can be 30mm, 32mm, 34mm, 36mm, 38mm or 40mm, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0036] Preferably, the pore size of the filter screen is 40 to 60 mesh, for example, it can be 40 mesh, 45 mesh, 50 mesh, 55 mesh or 60 mesh, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] It is worth noting that this invention achieves dual filtration through the setting of a filter and a filter screen, preventing crystallized particles from passing through the filter plate during the reaction process, thus reducing the purity of the products generated in the upper and middle parts of the reactor.

[0038] The method for resource recovery of fluoride-containing wastewater using the above-mentioned fluidized bed-based sodium fluorosilicate and cryolite co-recovery device includes the following steps: (1) Fluorine-containing wastewater and circulating water are mixed in the water distribution unit to obtain a mixed liquid, ensuring that the water distribution unit reaches a fluidized state; the mixed liquid is transported to the sodium fluorosilicate crystallization unit through a filtration device; (2) Using the first temperature control and dosing device, acid-base regulator and sodium element are added to the inside of the sodium fluorosilicate crystallization unit, and the temperature is controlled to obtain sodium fluorosilicate crystals and fluorine-containing mixed liquid; (3) The fluorine-containing mixed liquid obtained in step (2) is transported to the cryolite crystallization unit through a filtration device, and then acid-base regulator and aluminum element are added to the sodium fluorosilicate crystallization unit through the second temperature control and dosing device, and the temperature is controlled to obtain cryolite crystals, discharge wastewater and circulating water.

[0039] Preferably, the flow rate of the fluoride-containing wastewater in step (1) is 8~12m. 3 / h, for example, could be 8m 3 / h、9m 3 / h, 10m 3 / h、11m 3 / h or 12m 3 / h, etc., but not limited to the listed values, other unlisted values ​​within the range also apply.

[0040] Preferably, the conveying speed of the circulating water in step (1) is 280~320m. 3 / h, for example, could be 280m 3 / h、290m 3 / h, 300m 3 / h、310m 3 / h or 320m 3 / h, etc., but not limited to the listed values, other unlisted values ​​within the range also apply.

[0041] Preferably, the endpoint temperature for temperature control in step (2) is 40~60℃, for example, it can be 40℃, 45℃, 50℃, 55℃ or 60℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0042] Preferably, the endpoint of supplementing the acid-base regulator in step (2) is a pH value of 2 to 4 in the system. For example, it can be 2, 2.4, 2.8, 3.2, 3.6 or 4, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0043] Preferably, in step (2), the growth state of sodium fluorosilicate crystals is observed using a manhole-observation hole, and the sodium fluorosilicate crystals are discharged from the reactor through the first crystal outlet.

[0044] Preferably, the endpoint temperature for temperature control in step (3) is 70~80℃, for example, it can be 70℃, 72℃, 74℃, 76℃, 78℃ or 80℃, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0045] Preferably, the endpoint of supplementing the acid-base regulator in step (3) is a system pH value of 5 to 6, for example, it can be 5, 5.2, 5.4, 5.6, 5.8 or 6, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0046] Preferably, in step (3), the growth state of cryolite grains is observed using a manhole-observation hole, and the sodium fluorosilicate grains are discharged from the reactor through the second row of crystal outlets.

[0047] Preferably, in step (3), the wastewater is discharged from the reactor through the wastewater outlet pipe; the circulating water is connected to the circulating water outlet pipe through the circulating water outlet pipe, so that the circulating water circulates in the reactor and forms a fluidized state.

[0048] In this invention, by limiting the reaction temperature, pH and other conditions in the sodium fluorosilicate crystallization unit and the cryolite crystallization unit, the efficient recovery of fluoride resources in wastewater is achieved, resulting in high-purity sodium fluorosilicate crystals and cryolite crystals with large particles. After natural air drying, the moisture content can be reduced to below 10%, without the need for additional dehydration.

[0049] It is worth noting that, depending on the volume of fluoride-containing wastewater to be treated, those skilled in the art can increase or decrease the number of reaction units according to the actual reaction conditions. For example, the single-unit treatment capacity of this unit is 500m³. 3 / d, if the wastewater volume is 1000m³ 3 When the fluorine resource is / d, two units can be used in parallel to ensure efficient recovery of fluorine resources.

[0050] The numerical range described in this utility model includes not only the point values ​​listed above, but also any point values ​​within the numerical range not listed above. Due to space limitations and for the sake of brevity, this utility model will not exhaustively list the specific point values ​​included in the range.

[0051] The system refers to an equipment system, device system, or production device.

[0052] Compared with the prior art, the present invention has the following beneficial effects: (1) By setting up a layered structure, this utility model can simultaneously recover sodium fluorosilicate and cryolite, realizing the graded recovery of fluorine resources and effectively reducing the energy consumption of fluorine resource recovery; (2) The sodium fluorosilicate and cryolite obtained by the recycling device provided by this utility model have high purity and large particle size. After natural air drying, the moisture content can be reduced to below 10%, without the need for additional dehydration. (3) The recycling device provided by this utility model has a simple structure and is easy to operate, which is conducive to industrial application. Attached Figure Description

[0053] Figure 1 A front view of the fluidized bed-based sodium fluorosilicate and cryolite co-recovery device provided by this utility model; Figure 2 A cross-sectional view of the filtration device provided by this utility model; Figure 3 This is an installation diagram of the circulating water storage tank and wastewater storage tank provided by this utility model.

[0054] Wherein: 1 is the reactor body, 2 is the reactor body, 3 is the sodium fluorosilicate crystallization unit, 4 is the cryolite crystallization unit, 5 is the manhole-observation hole, 6-1 is the filter plate, 6-2 is the filter, 6-3 is the check plate, 6-4 is the filter screen, 7 is the fluoride wastewater inlet pipe, 8 is the circulating water inlet pipe, 9 is the vent pipe, 10 is the first crystal outlet, 11 is the first temperature control and dosing device, 12 is the second crystal outlet, 13 is the second temperature control and dosing device, 14 is the circulating water outlet pipe, 15 is the wastewater outlet pipe, 16 is the circulating water storage tank, and 17 is the wastewater storage tank. Detailed Implementation

[0055] It should be understood that in the description of this utility model, the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0056] It should be noted that, in the description of this utility model, unless otherwise explicitly specified and limited, the terms "set," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0057] The technical solution of this utility model will be further described below with reference to the accompanying drawings and specific embodiments.

[0058] Example 1 This embodiment provides a fluidized bed-based device for the synergistic recovery of sodium fluorosilicate and cryolite, such as... Figure 1 As shown, the recycling device includes a reactor body 1; From a direction perpendicular to the ground upwards, the reactor body 1 includes a water distribution unit 2, a sodium fluorosilicate crystallization unit 3, and a cryolite crystallization unit 4; The water distribution unit 2, sodium fluorosilicate crystallization unit 3 and cryolite crystallization unit 4 are connected by a filtration device; each of the water distribution unit 2, sodium fluorosilicate crystallization unit 3 and cryolite crystallization unit 4 has an independent manhole-observation hole 5 on its side wall; The height of the water distribution unit 2 is 1.2m; an vent pipe 9 is provided at the bottom of the side wall of the water distribution unit; a fluoride-containing wastewater inlet pipe 7 is provided at the top of the side wall of the water distribution unit 2; a circulating water inlet pipe 8 is provided on the side wall of the water distribution unit 2; the vertical height of the fluoride-containing wastewater inlet pipe 7 and the circulating water inlet pipe 8 is 12.5m. The height of the sodium fluorosilicate crystallization unit 3 is 4.5m; a first crystal outlet 10 is provided at the bottom of the side wall of the sodium fluorosilicate crystallization unit 3; a first temperature control and dosing device 11 is provided on the side wall of the sodium fluorosilicate crystallization unit 3; the vertical distance between the first temperature control and dosing device 11 and the first crystal outlet 10 is 0.8m. The height of the cryolite crystallization unit 4 is 6.5m; a second row of crystal openings 12 is provided at the bottom of the side wall of the cryolite crystallization unit 4; a second temperature control and dosing device 13 is provided on the side wall of the cryolite crystallization unit 4; the distance between the second temperature control and dosing device 13 and the second row of crystal openings 12 is 0.5m; The top of the four-element sidewall of the cryolite crystal is provided with a circulating water outlet pipe 14 and a wastewater outlet pipe 15; such as Figure 3As shown, a circulating water storage tank 16 and a wastewater storage tank 17 are fixedly installed inside the cryolite crystallization unit 4; the circulating water storage tank 16 is connected to the circulating water outlet pipe 14, and the wastewater storage tank 17 is connected to the wastewater outlet pipe 15; the distance between the top of the overflow weir of the circulating water storage tank 16 and the top of the overflow weir of the circulating water storage tank is 1600mm; the distance between the top of the overflow weir of the wastewater storage tank 17 and the top of the overflow weir of the circulating water storage tank is 1200mm. The circulating water outlet pipe 14 is connected to the circulating water inlet pipe 8; From the direction away from the fluoride-containing wastewater inlet pipe 7, such as Figure 2 As shown, the filtration device includes a filter plate 6-1, a filter 6-2, and a filter screen 6-4 arranged in sequence; a check plate 6-3 is provided at one end of the filter 6-2 near the filter screen 6-4; the average pore size of the filter plate 6-1 is 35 mm; and the pore size of the filter screen 6-4 is 40 to 60 mesh.

[0059] Example 2 This embodiment provides a fluidized bed-based device for the synergistic recovery of sodium fluorosilicate and cryolite, such as... Figure 1 As shown, the recycling device includes a reactor body 1; From a direction perpendicular to the ground upwards, the reactor body 1 includes a water distribution unit 2, a sodium fluorosilicate crystallization unit 3, and a cryolite crystallization unit 4; The water distribution unit 2, sodium fluorosilicate crystallization unit 3 and cryolite crystallization unit 4 are connected by a filtration device; each of the water distribution unit 2, sodium fluorosilicate crystallization unit 3 and cryolite crystallization unit 4 has an independent manhole-observation hole 5 on its side wall; The height of the water distribution unit 2 is 12m; an vent pipe 9 is provided at the bottom of the side wall of the water distribution unit; a fluoride-containing wastewater inlet pipe 7 is provided at the top of the side wall of the water distribution unit 2; a circulating water inlet pipe 8 is provided on the side wall of the water distribution unit 2; the vertical height of the fluoride-containing wastewater inlet pipe 7 and the circulating water inlet pipe 8 is 0.5m. The height of the sodium fluorosilicate crystallization unit 3 is 4m; a first crystal outlet 10 is provided at the bottom of the side wall of the sodium fluorosilicate crystallization unit 3; a first temperature control and dosing device 11 is provided on the side wall of the sodium fluorosilicate crystallization unit 3; the vertical distance between the first temperature control and dosing device 11 and the first crystal outlet 10 is 0.3m. The height of the cryolite crystallization unit 4 is 6m; a second row of crystal openings 12 is provided at the bottom of the side wall of the cryolite crystallization unit 4; a second temperature control and dosing device 13 is provided on the side wall of the cryolite crystallization unit 4; the distance between the second temperature control and dosing device 13 and the second row of crystal openings 12 is 0.3m; The top of the four-element sidewall of the cryolite crystal is provided with a circulating water outlet pipe 14 and a wastewater outlet pipe 15; such as Figure 3 As shown, a circulating water storage tank 16 and a wastewater storage tank 17 are fixedly installed inside the cryolite crystallization unit 4; the circulating water storage tank 16 is connected to the circulating water outlet pipe 14, and the wastewater storage tank 17 is connected to the wastewater outlet pipe 15; the distance between the top of the overflow weir of the circulating water storage tank 16 and the top of the overflow weir of the circulating water storage tank is 1800mm; the distance between the top of the overflow weir of the wastewater storage tank 17 and the top of the overflow weir of the circulating water storage tank is 1600mm. The circulating water outlet pipe 14 is connected to the circulating water inlet pipe 8; From the direction away from the fluoride-containing wastewater inlet pipe 7, such as Figure 2 As shown, the filtration device includes a filter plate 6-1, a filter 6-2, and a filter screen 6-4 arranged in sequence; a check plate 6-3 is provided at one end of the filter 6-2 near the filter screen 6-4; the average pore size of the filter plate 6-1 is 30 mm; and the pore size of the filter screen 6-4 is 40 to 60 mesh.

[0060] Example 3 This embodiment provides a fluidized bed-based device for the synergistic recovery of sodium fluorosilicate and cryolite, such as... Figure 1 As shown, the recycling device includes a reactor body 1; From a direction perpendicular to the ground upwards, the reactor body 1 includes a water distribution unit 2, a sodium fluorosilicate crystallization unit 3, and a cryolite crystallization unit 4; The water distribution unit 2, sodium fluorosilicate crystallization unit 3 and cryolite crystallization unit 4 are connected by a filtration device; each of the water distribution unit 2, sodium fluorosilicate crystallization unit 3 and cryolite crystallization unit 4 has an independent manhole-observation hole 5 on its side wall; The height of the water distribution unit 2 is 13m; an vent pipe 9 is provided at the bottom of the side wall of the water distribution unit; a fluoride-containing wastewater inlet pipe 7 is provided at the top of the side wall of the water distribution unit 2; a circulating water inlet pipe 8 is provided on the side wall of the water distribution unit 2; the vertical height of the fluoride-containing wastewater inlet pipe 7 and the circulating water inlet pipe 8 is 1.0m. The height of the sodium fluorosilicate crystallization unit 3 is 5m; a first crystal outlet 10 is provided at the bottom of the side wall of the sodium fluorosilicate crystallization unit 3; a first temperature control and dosing device 11 is provided on the side wall of the sodium fluorosilicate crystallization unit 3; the vertical distance between the first temperature control and dosing device 11 and the first crystal outlet 10 is 0.8m. The height of the cryolite crystallization unit 4 is 7m; a second row of crystal openings 12 is provided at the bottom of the side wall of the cryolite crystallization unit 4; a second temperature control and dosing device 13 is provided on the side wall of the cryolite crystallization unit 4; the distance between the second temperature control and dosing device 13 and the second row of crystal openings 12 is 0.8m; The top of the four-element sidewall of the cryolite crystal is provided with a circulating water outlet pipe 14 and a wastewater outlet pipe 15; such as Figure 3 As shown, a circulating water storage tank 16 and a wastewater storage tank 17 are fixedly installed inside the cryolite crystallization unit 4; the circulating water storage tank 16 is connected to the circulating water outlet pipe 14, and the wastewater storage tank 17 is connected to the wastewater outlet pipe 15; the distance between the top of the overflow weir of the circulating water storage tank 16 and the top of the overflow weir of the circulating water storage tank is 1400mm; the distance between the top of the overflow weir of the wastewater storage tank 17 and the top of the overflow weir of the circulating water storage tank is 1200mm. The circulating water outlet pipe 14 is connected to the circulating water inlet pipe 8; From the direction away from the fluoride-containing wastewater inlet pipe 7, such as Figure 2 As shown, the filtration device includes a filter plate 6-1, a filter 6-2, and a filter screen 6-4 arranged in sequence; a check plate 6-3 is provided at one end of the filter 6-2 near the filter screen 6-4; the average pore size of the filter plate 6-1 is 40 mm; and the pore size of the filter screen 6-4 is 40 to 60 mesh.

[0061] Example 4 This embodiment provides a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. The only difference between this recovery device and that of Embodiment 1 is: This embodiment omits the filter and screen in the filtration device.

[0062] Example 5 This embodiment provides a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. The only difference between this recovery device and that of Embodiment 1 is: This embodiment omits the inclusion of a check plate in the filter.

[0063] Example 6 This embodiment provides a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. The only difference between this recovery device and that of Embodiment 1 is: This embodiment omits the manhole-observation hole configuration.

[0064] Example 7 This embodiment provides a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. The only difference between this recovery device and that of Embodiment 1 is: In this embodiment, the height difference between the overflow weir of the circulating water storage tank and the overflow weir of the wastewater storage tank is adjusted to 0, that is, the two are set on the same horizontal plane.

[0065] Comparative Example 1 This comparative example provides a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. The only difference between this recovery device and Example 1 is that: This comparative example omits the filtration device installed between the water replenishment unit and the sodium fluorosilicate crystallization unit.

[0066] Comparative Example 2 This comparative example provides a fluidized bed-based synergistic recovery device for sodium fluorosilicate and cryolite. The only difference between this recovery device and Example 1 is that: This comparative example omits the filtration device installed between the sodium fluorosilicate crystallization unit and the cryolite crystallization unit.

[0067] Application examples This application example provides a method for the resource recovery treatment of fluoride-containing wastewater using the fluidized bed-based sodium fluorosilicate and cryolite co-recovery device provided in the above embodiments and comparative examples. The method includes the following steps: (1) Fluorine-containing wastewater and circulating water are mixed in the water distribution unit to obtain a mixed liquid, ensuring that the water distribution unit reaches a fluidized state; the mixed liquid is transported to the sodium fluorosilicate crystallization unit through a filtration device; The flow rate of the fluoride-containing wastewater is 10 m / s. 3 The circulating water is transported at a rate of 300 m / h. 3 / h; The endpoint temperature for temperature control is 50°C, and the endpoint for supplementing the acid-base regulator is a system pH of 3. (2) Using the first temperature control and dosing device, acid-base regulator and sodium element are added to the inside of the sodium fluorosilicate crystallization unit, and the temperature is controlled to obtain sodium fluorosilicate crystals and fluorine-containing mixed liquid; The endpoint temperature for temperature control is 75°C, and the endpoint for supplementing the acid-base regulator is a system pH value of 5.5. (3) The fluorine-containing mixed liquid obtained in step (2) is transported to the cryolite crystallization unit through a filtration device, and then acid-base regulator and aluminum element are added to the sodium fluorosilicate crystallization unit through the second temperature control and dosing device, and the temperature is controlled to obtain cryolite crystals, discharge wastewater and circulating water.

[0068] Performance testing: The performance of cryolite and sodium fluorosilicate grains obtained by the fluidized bed-based sodium fluorosilicate and cryolite co-recovery device provided in the above embodiments and comparative examples is shown in Table 1. The performance testing includes purity testing and moisture content testing; The moisture content was measured by testing the grains after they had been air-dried for 5 hours.

[0069] Table 1 According to Table 1, the following points can be observed: (1) Analysis of Examples 1-3 shows that the recycling device provided by this utility model can simultaneously generate high-purity sodium fluorosilicate and cryolite, thereby realizing the recycling of fluorine resources; (2) Comprehensive analysis of Examples 1 and 4-5 shows that the setting of the filtration device will affect the purity of the obtained cryolite crystals and sodium fluorosilicate crystals; (3) Comprehensive analysis of Examples 1 and 6 shows that when the manhole-observation hole is omitted, it is impossible to judge the growth rate and extent of the grains in the reaction unit in time, which makes it impossible to discharge the grains in time or to discharge the grains in advance, which may result in the product particle size being too small. (4) Comprehensive analysis of Examples 1 and 7 shows that when the overflow weir heights of the circulating water storage tank and the wastewater storage tank are at the same level, the treated wastewater and circulating water in the reaction unit cannot be separated, which may lead to the circulating water level being too low, the water pump not working properly, resulting in no circulating water input in the water distribution unit, thus affecting the crystallization reaction. (5) Comprehensive analysis of Example 1 and Comparative Examples 1-2 shows that omitting the filtration device will cause the crystallization of sodium fluorosilicate and cryolite to affect each other, resulting in a decrease in the purity of both.

[0070] In summary, this invention, through its layered structure, can simultaneously recover sodium fluorosilicate and cryolite, achieving graded recovery of fluorine resources and effectively reducing energy consumption in fluorine resource recovery. Furthermore, the recovery device has a simple structure, is easy to operate, and is conducive to industrial application.

[0071] The applicant declares that the above description is only a specific embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present utility model fall within the protection and disclosure scope of the present utility model.

Claims

1. A fluidized bed-based device for the co-recovery of sodium fluorosilicate and cryolite, characterized in that, The recovery device includes a reactor body; The reactor body includes a water distribution unit, a sodium fluorosilicate crystallization unit, and a cryolite crystallization unit, which are located in the direction perpendicular to the ground and pointing upwards.

2. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 1, characterized in that, The water distribution unit, sodium fluorosilicate crystallization unit, and cryolite crystallization unit are connected by a filtration device. The sidewalls of the water distribution unit, sodium fluorosilicate crystallization unit, and cryolite crystallization unit are each independently provided with a manhole-observation hole.

3. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 1, characterized in that, The height of the water distribution unit is 12~13m; An vent pipe is provided at the bottom of the side wall of the water distribution unit; A fluoride-containing wastewater inlet pipe is provided at the top of the side wall of the water distribution unit. The side wall of the water distribution unit is provided with a circulating water inlet pipe; The vertical height of the fluoride-containing wastewater inlet pipe and the circulating water inlet pipe is 0.5~1m.

4. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 1, characterized in that, The height of the sodium fluorosilicate crystallization unit is 4~5m; The bottom end of the sidewall of the sodium fluorosilicate crystallization unit is provided with a first crystal outlet; The sidewall of the sodium fluorosilicate crystallization unit is provided with a first temperature control and dosing device; The vertical distance between the first temperature control and dosing device and the first crystal port is 0.3~0.8m.

5. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 1, characterized in that, The height of the cryolite crystallization unit is 6~7m; The bottom end of the sidewall of the cryolite crystallization unit is provided with a second row of crystal openings; The cryolite crystallization unit is equipped with a second temperature control and dosing device on its side wall. The distance between the second temperature control and dosing device and the second crystal outlet is 0.3~0.8m.

6. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 5, characterized in that, The top of the sidewall of the cryolite crystallization unit is provided with a circulating water outlet pipe and a wastewater outlet pipe. The cryolite crystallization unit is equipped with a circulating water storage tank and a wastewater storage tank. The circulating water storage tank is connected to the circulating water outlet pipe, and the wastewater storage tank is connected to the wastewater outlet pipe.

7. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 6, characterized in that, The distance between the overflow weir of the circulating water storage tank and the top of the cryolite crystallization unit is 1200~1600mm; The distance between the overflow weir of the wastewater storage tank and the top of the cryolite crystallization unit is 1200~1800mm; The distance between the overflow weir of the circulating water storage tank and the top of the cryolite crystallization unit is smaller than the distance between the overflow weir of the wastewater storage tank and the top of the cryolite crystallization unit.

8. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 6, characterized in that, The circulating water outlet pipe is connected to the circulating water inlet pipe.

9. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 2, characterized in that, From the direction away from the inlet pipe of fluoride-containing wastewater, the filtration device includes a filter plate, a filter, and a filter screen arranged in sequence; A check plate is provided at the end of the filter near the filter screen.

10. The fluidized bed-based sodium fluorosilicate and cryolite co-recovery device according to claim 9, characterized in that, The average pore size of the filter plate is 30~40mm; The filter screen has a pore size of 40-60 mesh.

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