A device for adsorbing metal ions in brine

Abstract

The utility model provides a device of adsorbing metal ions in brine, including brine main pipe, brine main pipe connects weak cation resin tower, weak cation resin tower is connected through brine discharge pipeline strong cation resin tower. Weak cation resin tower and strong cation resin tower are connected through the regeneration liquid discharge pipeline alkali waste water storage tank and acidic waste water storage tank. The utility model discloses a change adsorbs metal ions in brine's craft, adopts the mode of increasing the resin selection of purification tower, makes full use of weak positive resin and strong positive resin characteristics, effectively avoids the problem of the metal ions in brine, the frequent regeneration cycle, the unstable process control.

Description

Technical Field

[0001] This utility model relates to the field of high-purity chemical production in chlor-alkali chemical industry, specifically to a device for adsorbing metal ions in brine. Background Technology

[0002] In the chlor-alkali industry, resin towers are typically used for primary brine purification and filtration. Traditionally, three resin towers operate in series, with one tower being removed for regeneration after its adsorption capacity becomes saturated. However, traditional brine typically uses quaternary ammonium-type strong cation exchange resins. These resins contain a large number of strongly acidic groups, such as sulfonic acid groups (-SO3H), which readily dissociate into H+ in solution. + When cations in the solution (such as sodium, calcium, magnesium, and ammonium ions) come into contact with the resin, the functional groups on the resin surface, which have a certain positive charge, will adsorb and exchange negatively charged ions. Currently, in the production process of tetramethylammonium hydroxide (TMAH), the raw material is usually recycled waste liquid from the developing stage of upstream panel manufacturers. This waste liquid contains a large number of metal ions, including lithium, sodium, magnesium, aluminum, potassium, calcium, chromium, manganese, iron, cobalt, nickel, copper, zinc, arsenic, silver, cadmium, barium, thallium, lead, and more than twenty others. However, electronic-grade TMAH products have very high quality requirements, with a main content deviation of ±0.1% and a metal ion content requirement of below 5 ppb. Using traditional resin towers for filtration directly leads to frequent exceedances of heavy metal ions in the product, resulting in unstable process control. Utility Model Content

[0003] To address the aforementioned problems, this invention provides a device for adsorbing metal ions from brine, comprising a brine main pipe connected to a weak cation exchange resin tower, and the weak cation exchange resin tower connected to a strong cation exchange resin tower via a brine outlet pipeline.

[0004] Furthermore, both the weakly cationic resin tower and the strongly cationic resin tower are connected to the alkaline wastewater storage tank and the acidic wastewater storage tank through regenerated liquid discharge pipelines.

[0005] Furthermore, the brine main pipe is equipped with a flow meter, a pH meter, and a control valve.

[0006] Furthermore, both the weakly cationic resin tower and the strongly cationic resin tower are connected to the regenerated liquid feed pipeline.

[0007] Furthermore, both the weakly cationic resin tower and the strongly cationic resin tower are resin towers made of steel lined with PTFE.

[0008] Furthermore, the pipelines connected to both the weak cation-type resin tower and the strong cation-type resin tower are made of steel lined with PTFE.

[0009] Furthermore, the number of the weakly cationic resin towers is no less than three, and the weakly cationic resin towers are connected in series.

[0010] Furthermore, the number of strong cation-type resin towers is not less than two, and the strong cation-type resin towers are connected in series.

[0011] Furthermore, valves are provided at the inlet and outlet ends of the weak cation type resin tower and the strong cation type resin tower, as well as at the inlet ends of the alkaline wastewater storage tank and the acidic wastewater storage tank.

[0012] Furthermore, pressure sensors and flow meters are installed at the inlets of both the weak cation type resin tower and the strong cation type resin tower.

[0013] The beneficial effects of this utility model are as follows: By modifying the process for adsorbing metal ions in brine and increasing the selection of resins in the purification tower, the characteristics of weakly positive and strongly positive resins are fully utilized, effectively avoiding problems such as high metal ion content in brine, frequent regeneration cycles, and unstable process control. Attached Figure Description

[0014] Figure 1 Schematic diagram of the device described in this utility model.

[0015] The markings in the diagram are as follows: Weak cationic resin tower 101, strong cationic resin tower 102, alkaline wastewater storage tank 2, acidic wastewater storage tank 3, brine main pipe 4, brine discharge pipeline 5, regenerated liquid discharge pipeline 6, regenerated liquid inlet pipeline 7, flow meter 401, pH meter 402, and control valve 403.

[0016] A / B / C represent the numbers of multiple identical weak cationic resin towers; D / E represent the numbers of multiple identical strong cationic resin towers. Detailed Implementation

[0017] The embodiments of this utility model will be described in detail below with reference to the examples. The following examples are only used to illustrate this utility model and should not be regarded as limiting the scope of this utility model.

[0018] Example 1 like Figure 1 As shown, an apparatus for adsorbing metal ions in brine includes a brine main pipe 4, which is connected to a weak cation exchange resin tower 101. The weak cation exchange resin tower 101 is connected to a strong cation exchange resin tower 102 via a brine outlet pipeline 5.

[0019] Furthermore, both the weakly cationic resin tower 101 and the strongly cationic resin tower 102 are connected to the alkaline wastewater storage tank 2 and the acidic wastewater storage tank 3 through the regenerated liquid discharge pipeline 6.

[0020] Furthermore, the brine main pipe 4 is equipped with a flow meter 401, a pH meter 402, and a control valve 403.

[0021] Furthermore, both the weakly cationic resin tower 101 and the strongly cationic resin tower 102 are connected to the regenerated liquid feed line 7.

[0022] Furthermore, both the weakly cationic resin tower 101 and the strongly cationic resin tower 102 are resin towers made of steel lined with PTFE.

[0023] Furthermore, the pipelines connected to the weak cation type resin tower 101 and the strong cation type resin tower 102 are all made of steel lined with PTFE.

[0024] Furthermore, the number of the weakly cationic resin towers 101 is not less than three, and the weakly cationic resin towers 101 are connected in series.

[0025] Furthermore, the number of strong cation-type resin towers 102 is not less than two, and the strong cation-type resin towers 102 are connected in series.

[0026] Furthermore, valves are provided at the inlet and outlet ends of the weak cation type resin tower 101 and the strong cation type resin tower 102, as well as at the inlet ends of the alkaline wastewater storage tank 2 and the acidic wastewater storage tank 3.

[0027] Furthermore, pressure sensors and flow meters are installed at the inlets of both the weak cation type resin tower 101 and the strong cation type resin tower 102.

[0028] Example 2 use Figure 1 The device shown operates as follows: A primary brine solution sequentially enters columns A, B, and C of a weakly cationic resin column 101, containing cations (such as Na+). + Ca 2+ Mg 2+ When brine (e.g., salt water) flows through a weakly cationic ion exchange resin, the cations in the brine are reacted with H+ ions on the resin. + Ions are attracted and exchanged; subsequently, the brine enters the D and E towers of the strong cation exchange resin tower 102 sequentially through the brine outlet pipeline 5, where the strong cation exchange resin adsorbs and filters the chelated brine again; finally, the brine flows out of the strong cation exchange resin tower 102 and enters the subsequent electrolysis process.

[0029] Tower A, acting as a primary tower, experiences higher adsorption pressure and a relatively faster saturation time. Once the adsorption drops to the target value, it needs to be switched off for regeneration. The regeneration process is as follows: Tetramethylammonium hydroxide, hydrochloric acid, or pure water enters tower A sequentially via regeneration feed line 7. The regeneration solution flows out from the bottom of tower A and exits via regeneration discharge line 6 into alkaline wastewater storage tank 2 or acidic wastewater storage tank 3. During regeneration, tower B acts as a primary tower, with the primary brine sequentially flowing through towers B, C, D, and E. After regeneration, tower A is reconnected to the weak cation exchange resin tower in the purification system as a secondary tower, meaning the brine flows sequentially through towers B, C, A, D, and E.

[0030] Similarly, when tower B becomes saturated, it is shut off for regeneration. At this point, tower C becomes tower one, and the refined brine sequentially flows into towers C, A, D, and E. After regeneration, tower B is reintegrated into the weak cation exchange resin tower of the purification system as tower three, meaning the brine flows sequentially through towers C, A, B, D, and E. When tower D becomes saturated, it is shut off for regeneration. The brine flowing from the third weak cation exchange resin tower 101 enters tower E via brine outlet pipeline 5. After tower D's regeneration is complete, it is reintegrated into the strong cation exchange resin tower system, and the brine flowing through brine outlet pipeline 5 sequentially flows through towers E and D, completing the adsorption purification.

[0031] right Figure 1The device shown was tested for one week: the control valves at the inlet and outlet of A / B / C / D / E were opened, the pipeline connection valves between the towers were opened, all regeneration valves were checked to be closed, and the liquid level in brine storage tank 7 was monitored to see if it rose. Start the brine pump to feed the resin towers, adjusting the flow rate to 0.8-1 m³ / h. Observe the inlet pressure of tower A (55 kPa), tower B (35 kPa), tower C (25 kPa), tower D (18 kPa), and tower E (14 kPa). The resin towers can withstand pressures within 160 kPa. ICP testing is performed on brine samples taken from the outlets of each tower. The overall metal ion content at the outlet of tower A is approximately 22 ppb, tower B is approximately 11 ppb, tower C is approximately 6 ppb, tower D is below 5 ppb, and tower E is approximately 1 ppb. Some indicators, such as iron, sodium, calcium, and magnesium, are below 0.5 ppb or even lower. Due to the characteristics of weakly and strongly cationized resins, the pH requirement for the upstream brine is relatively high, ideally controlled between 8.5 and 11, with zero free chlorine. If the pH is too high, it will cause the precipitation of silver and aluminum elements in the weak cation exchange resin, affecting the normal operation of subsequent processes. If the pH is below 7 or free chlorine enters, the metal ions adsorbed on the resin will directly detach, resulting in substandard brine process. In severe cases, the electrolyzer needs to be shut down urgently. According to ICP analysis results, the pH of the brine entering the weak cation exchange resin tower 101 is 8.5-11, and the pH of the brine entering the strong cation exchange resin tower 102 is 7-11.

[0032] After the trial run, statistics were compiled, and the results are as follows: After one week, the ICP index at the outlets of resin towers D and E were both below 1 ppb, the operating flow rate and tower pressure were stable, and the metal content of the product was below 1 ppb, meeting the G3 level for electronic chemicals. The operational results indicate that changing the adsorption method of the two resins in the resin towers can effectively remove a large number of metal ions from the raw materials, improve product quality, and stabilize the brine quality control in the brine process. This modification was successful.

Claims

1. A device for adsorbing metal ions from salt water, characterized in that, It includes a brine main pipe (4), which is connected to a weak cation resin tower (101), and the weak cation resin tower (101) is connected to a strong cation resin tower (102) through a brine discharge pipeline (5).

2. The device for adsorbing metal ions in salt water according to claim 1, characterized in that, Both the weak cationic resin tower (101) and the strong cationic resin tower (102) are connected to the alkaline wastewater storage tank (2) and the acidic wastewater storage tank (3) through the regenerated liquid discharge pipeline (6).

3. The device for adsorbing metal ions in salt water according to claim 1, characterized in that, The brine main pipe (4) is equipped with a flow meter (401), a pH meter (402) and a control valve (403).

4. The device for adsorbing metal ions in salt water according to claim 1, characterized in that, Both the weak cationic resin tower (101) and the strong cationic resin tower (102) are connected to the regenerated liquid feed line (7).

5. The device for adsorbing metal ions in salt water according to claim 1, characterized in that, Both the weak cation type resin tower (101) and the strong cation type resin tower (102) are resin towers made of steel lined with PTFE.

6. The apparatus for adsorbing metal ions in brine according to claim 1, characterized in that, The pipelines connected to the weak cation type resin tower (101) and the strong cation type resin tower (102) are all made of steel lined with PTFE.

7. The apparatus for adsorbing metal ions in brine according to claim 1, characterized in that, The number of weak cationic resin towers (101) is not less than 3, and the weak cationic resin towers (101) are connected in series.

8. The apparatus for adsorbing metal ions in salt water according to claim 1, characterized in that, The number of strong cation-type resin towers (102) is not less than two, and the strong cation-type resin towers (102) are connected in series with each other.

9. The apparatus for adsorbing metal ions in brine according to claim 1, characterized in that, Valves are provided at the inlet and outlet ends of the weak cation type resin tower (101) and the strong cation type resin tower (102), as well as at the inlet ends of the alkaline wastewater storage tank (2) and the acidic wastewater storage tank (3).

10. The apparatus for adsorbing metal ions in brine according to claim 1, characterized in that, Pressure sensors and flow meters are installed at the inlets of both the weak cation type resin tower (101) and the strong cation type resin tower (102).

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