A process device for extracting elemental iodine from a fluosilicic acid solution

Abstract

The utility model relates to fluorine chemical industry technical field, concretely is a kind of process device for extracting iodine element from fluosilicic acid solution, including fluosilicic acid groove (1), micropore filter (2), resin adsorption tower (3), circulating pump (4) and compressed air backwashing system (5), the discharge outlet of fluosilicic acid groove (1) is connected to the inlet of circulating pump (4) by pipeline, the outlet of circulating pump (4) is connected to the inlet of micropore filter (2) by pipeline, the filtrate outlet of micropore filter (2) is connected to the inlet of resin adsorption tower (3) by pipeline, the outlet of resin adsorption tower (3) is connected back to fluosilicic acid groove (1) by pipeline, constitute a closed loop circulating system, compressed air backwashing system (5) is connected to micropore filter (2) by pipeline, for the back blow of micropore filter (2) is carried out clear residue, the utility model provides the device of high efficiency removal iodine.

Description

Technical Field

[0001] This utility model relates to the technical field of the fluorochemical industry, specifically to a process device for extracting elemental iodine from a fluorosilicic acid solution. Background Technology

[0002] In the production of phosphoric acid, iodine is a byproduct of the process. The raw phosphate rock (such as apatite) contains iodine, which enters the fluorosilicic acid solution during processing. The presence of large amounts of iodine can negatively impact the subsequent production of other chemical products using fluorosilicic acid as a raw material. For example, iodine may adhere to heat exchanger pipes or walls in the condensation system, causing blockages, or it may escape from the scrubbing system under the action of oxidizing agents, forming "red smoke" and potentially causing environmental incidents.

[0003] Existing technologies remove iodine from fluorosilicic acid solutions using microporous filtration and activated carbon adsorption. For example, patent CN222368559U describes a microporous filter for efficient deiodination of concentrated fluorosilicic acid. The microporous filter intercepts solid particles and colloidal substances in the solution. The intercepted filtrate reacts with hydrogen peroxide solution and is then pumped to fully contact activated carbon for iodine removal. However, traditional activated carbon deiodination efficiency is low, and it is easily affected by the high acidity of fluorosilicic acid, resulting in limited adsorption capacity. Therefore, there is an urgent need for a highly efficient and precisely targeted iodine removal device. Utility Model Content

[0004] This invention provides a process apparatus for extracting elemental iodine from a fluorosilicic acid solution, aiming to solve the problem of low iodine removal efficiency in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a process device for extracting iodine from a fluorosilicic acid solution, comprising a fluorosilicic acid tank (1), a microporous filter (2), a resin adsorption tower (3), a circulating pump (4), and a compressed air backflushing system (5); the outlet of the fluorosilicic acid tank (1) is connected to the inlet of the circulating pump (4) via a pipe; the outlet of the circulating pump (4) is connected to the inlet of the microporous filter (2) via a pipe; the filtrate outlet of the microporous filter (2) is connected to the inlet of the resin adsorption tower (3) via a pipe; the outlet of the resin adsorption tower (3) is connected back to the fluorosilicic acid tank (1) via a pipe, forming a closed-loop circulation system; the compressed air backflushing system (5) is connected to the microporous filter (2) via a pipe for backflushing and cleaning the microporous filter (2).

[0006] Furthermore, the resin adsorption tower (3) is filled with a targeted resin for adsorbing iodine.

[0007] Furthermore, it also includes a slag tank (6), and the slag discharge port of the microporous filter (2) and the waste liquid discharge port of the resin adsorption tower (3) are both connected to the slag tank (6) through pipelines.

[0008] Furthermore, regulating valves (7) for controlling flow rate are provided on the pipeline between the circulating pump (4) and the resin adsorption tower (3).

[0009] Furthermore, it also includes a cleaning system (8), which is connected to the resin adsorption tower (3) via a pipeline and is used to deliver cleaning liquid into the resin adsorption tower (3).

[0010] Furthermore, it also includes a flow sensor (9) installed on the pipeline and a differential pressure monitor (10) installed in the resin adsorption tower (3). The flow sensor (9) is connected to the compressed air backflushing system (5) and the differential pressure monitor (10) is connected to the cleaning system (8).

[0011] Furthermore, it also includes an iodine concentration monitor (11), which is installed on the outlet pipe of the resin adsorption tower (3) for monitoring the iodine concentration; the iodine concentration monitor (11) is connected to the cleaning system (8) via a signal.

[0012] Compared with existing technologies, the beneficial effects of this solution are: 1. Highly efficient iodine removal and precise targeted adsorption: Existing technologies using traditional activated carbon or activated fiber membranes have low iodine removal efficiency and are easily affected by the high acidity of fluorosilicic acid (pH≤2), resulting in limited adsorption capacity. This solution uses a strongly basic anion exchange resin or a functionalized resin with specific adsorption function for iodine, specifically designed for iodine ions / elemental substances, with an adsorption capacity ≥1.1mol / L. It can reduce iodine in fluorosilicic acid from 20ppm to ≤0.1ppm (removal rate ≥99.5%), far exceeding industry standards.

[0013] 2. Optimized pretreatment to avoid resin contamination: Direct adsorption in resin adsorption towers is prone to clogging due to the high solid content of fluorosilicic acid (silica gel), requiring frequent replacement and resulting in high operating costs. This solution uses microporous filtration pretreatment (precision ≤50μm) to remove silica and scum, significantly reducing the risk of resin encapsulation and extending resin life (efficiency remains above 90% after ≥50 regeneration cycles).

[0014] 3. High regeneration rate and low operating cost: In existing technologies, activated carbon cannot be regenerated and needs to be replaced regularly; activated fiber membranes are complex to clean and waste liquid is difficult to treat. This solution uses resin that can be regenerated stepwise with sodium bisulfite and hydrochloric acid, resulting in a small amount of waste liquid (only 2 BV), and it can be co-recovered with silica filter cake to the phosphoric acid unit, realizing resource utilization and reducing overall costs by more than 40%.

[0015] 4. Closed-loop circulation throughout the entire process, with significant environmental advantages: This solution achieves zero wastewater discharge, recycling of regenerated waste liquid, and no new pollution; iodine removal is thorough, and there is no "red smoke" phenomenon in the exhaust gas in summer (iodine content ≤1ppm), and the exhaust gas meets the standards.

[0016] 5. High degree of automation and convenient maintenance: This solution adopts intelligent control, automatically triggering backflushing and cleaning through flow monitoring (e.g., when the flow rate drops to 5m³ / h). 3 (Starts at / h); and adopts a modular design, allowing for quick disassembly and maintenance of the microporous filter and resin adsorption tower, reducing downtime by 70%. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall structure of a process device for extracting elemental iodine from a fluorosilicic acid solution according to the present invention.

[0018] In the diagram: 1-Fluorosilicic acid tank; 2-Microporous filter; 3-Resin adsorption tower; 4-Circulating pump; 5-Compressed air backflushing system; 6-Slag tank; 7-Regulating valve; 8-Cleaning system; 9-Flow sensor; 10-Differential pressure monitor; 11-Iodine concentration monitor. Detailed Implementation

[0019] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0020] Implementation, for example, attached Figure 1As shown: This embodiment is a process apparatus for extracting elemental iodine from a fluorosilicic acid solution, including a fluorosilicic acid tank 1, a microporous filter 2, a resin adsorption tower 3, a circulating pump 4, and a compressed air backflushing system 5. The outlet of the fluorosilicic acid tank 1 is connected to the inlet of the circulating pump 4 via a pipeline. The outlet of the circulating pump 4 is connected to the inlet of the microporous filter 2 via a pipeline. The filtrate outlet of the microporous filter 2 is connected to the inlet of the resin adsorption tower 3 via a pipeline. The outlet of the resin adsorption tower 3 is connected back to the fluorosilicic acid tank 1 via a pipeline, forming a closed-loop circulation system. Flow control valves 7 are installed on the pipelines between the circulating pump 4 and the resin adsorption tower 3. The compressed air backflushing system 5 is connected to the microporous filter 2 via a pipeline for backflushing and cleaning the microporous filter 2 to prevent clogging. In fluorosilicic acid solution, iodine may exist as iodide ions or complex anions formed through oxidation. The resin adsorption tower 3 is filled with a strong base anion exchange resin or a functionalized resin with specific adsorption function for iodine. The active groups of the strong base anion exchange resin (such as quaternary ammonium type) can effectively exchange with these anions to achieve adsorption, thus achieving precise targeted adsorption of iodine.

[0021] This device also includes a slag tank 6, a cleaning system 8, a flow sensor 9, a differential pressure monitor 10, and an iodine concentration monitor 11. The slag discharge port of the microporous filter 2 and the waste liquid discharge port of the resin adsorption tower 3 are both connected to the slag tank 6 via pipelines. The cleaning system 8 is connected to the resin adsorption tower 3 via a pipeline. The cleaning system 8 contains different cleaning solutions and delivers the cleaning solutions to the resin adsorption tower 3. The waste liquid after cleaning is discharged into the slag tank 6 through the waste liquid discharge port of the resin adsorption tower 3. A flow sensor 9 is installed on the circulation pipeline, which is connected to the compressed air backflushing system 5. The flow rate is monitored by the flow sensor 9, and the compressed air backflushing system 5 is automatically triggered. A differential pressure monitor 10 is installed inside the resin adsorption tower 3 and connected to the cleaning system 8. The monitor monitor 10 monitors the pressure difference generated by the fluid flowing through the bed of the resin adsorption tower 3. During circulation, if the resin bed is blocked by suspended solids, or if the resin particles break or agglomerate, reducing the bed porosity, the resistance to fluid flow increases, and the pressure difference between the inlet and outlet of the resin adsorption tower 3 rises. When an increase in the pressure difference between the inlet and outlet of the resin adsorption tower 3 is detected, the cleaning system 8 is triggered to perform online chemical cleaning of the resin adsorption tower 3. An iodine concentration monitor 11 is installed on the outlet pipe of the resin adsorption tower 3 and connected to the cleaning system 8. It monitors the iodine concentration. During circulation, when the resin adsorption decreases or approaches saturation, the iodine concentration on the outlet pipe increases (exceeding a preset threshold) or remains unchanged, triggering the cleaning system 8 to start the resin regeneration program.

[0022] Working principle: The fluorosilicic acid solution to be treated is stored in the fluorosilicic acid tank 1. The circulation pump 4 is started to pump the fluorosilicic acid solution into the microporous filter 2. The microporous filter 2 preferably has a filtration accuracy of ≤50μm, used to remove fine particles of silica and foam from the solution. The pretreated filtrate enters the resin adsorption tower 3, which is filled with a strongly basic anion exchange targeted resin with high selectivity and high adsorption capacity (≥1.1mol / L) for iodide ions / elements. As the fluorosilicic acid solution flows through the resin bed, iodine is efficiently adsorbed. The purified liquid after iodine removal returns to the fluorosilicic acid tank 1, completing one cycle. The feed flow rate can be controlled between 10~20m³ by adjusting valve 7. 3 Within the optimized range of / h. When the flow rate of the microporous filter 2 decreases due to filter cake accumulation (e.g., drops to 50%~60% of the initial value), the compressed air backflushing system 5 is triggered based on the signal from the flow sensor 9. At this time, the regulating valve 7 is closed, and the filter cake is blown to the slag tank 6 for centralized treatment. Alternatively, when the adsorption efficiency of the resin adsorption tower 3 decreases or after adsorption saturation, the iodine concentration monitor 11 detects an increase or no change in the iodine concentration on the outlet pipe, triggering the cleaning system 8 to start the resin regeneration program to clean the resin adsorption tower 3. When the pressure difference of the resin adsorption tower 3 increases, the pressure difference monitor 10 can also trigger the cleaning system 8 to start. The cleaning system 8 mainly uses sodium bisulfite and hydrochloric acid solutions sequentially to clean the resin in the resin adsorption tower 3, restoring the resin activity and achieving stepwise regeneration. The regeneration waste liquid and rinsing liquid are discharged into the slag tank 6 together.

[0023] The entire device operates in a closed-loop cycle, achieving highly efficient iodine extraction.

[0024] The above descriptions are merely embodiments of this utility model, and common knowledge regarding specific structures and characteristics is not elaborated upon here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the structure of this utility model, and these should also be considered within the scope of protection of this utility model. These modifications will not affect the effectiveness of the implementation of this utility model or the practicality of the patent. The scope of protection claimed in this application shall be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A process apparatus for extracting elemental iodine from a fluorosilicic acid solution, characterized in that, include: The system comprises a fluorosilicic acid tank (1), a microporous filter (2), a resin adsorption tower (3), a circulating pump (4), and a compressed air backflushing system (5); the outlet of the fluorosilicic acid tank (1) is connected to the inlet of the circulating pump (4) via a pipe; the outlet of the circulating pump (4) is connected to the inlet of the microporous filter (2) via a pipe; the filtrate outlet of the microporous filter (2) is connected to the inlet of the resin adsorption tower (3) via a pipe; the outlet of the resin adsorption tower (3) is connected back to the fluorosilicic acid tank (1) via a pipe, forming a closed-loop circulation system; the compressed air backflushing system (5) is connected to the microporous filter (2) via a pipe for backflushing and cleaning the microporous filter (2).

2. The apparatus for extracting elemental iodine from a fluorosilicic acid solution according to claim 1, characterized in that: The resin adsorption tower (3) is filled with a targeted resin for adsorbing iodine.

3. The apparatus for extracting elemental iodine from a fluorosilicic acid solution according to claim 1, characterized in that: It also includes a slag tank (6), and the slag discharge port of the microporous filter (2) and the waste liquid discharge port of the resin adsorption tower (3) are all connected to the slag tank (6) through pipelines.

4. The apparatus for extracting elemental iodine from a fluorosilicic acid solution according to claim 1, characterized in that: A regulating valve (7) for controlling the flow rate is provided on the pipeline between the circulating pump (4) and the resin adsorption tower (3).

5. The apparatus for extracting elemental iodine from a fluorosilicic acid solution according to claim 1, characterized in that: It also includes a cleaning system (8), which is connected to the resin adsorption tower (3) via a pipeline and is used to deliver cleaning liquid to the resin adsorption tower (3).

6. The apparatus for extracting elemental iodine from a fluorosilicic acid solution according to claim 5, characterized in that: It also includes a flow sensor (9) installed on the pipeline and a differential pressure monitor (10) installed in the resin adsorption tower (3). The flow sensor (9) is connected to the compressed air backflushing system (5) and the differential pressure monitor (10) is connected to the cleaning system (8).

7. The apparatus for extracting elemental iodine from a fluorosilicic acid solution according to claim 6, characterized in that: It also includes an iodine concentration monitor (11), which is installed on the outlet pipe of the resin adsorption tower (3) for monitoring the iodine concentration; the iodine concentration monitor (11) is connected to the cleaning system (8) via signal connection.

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