Comprehensive recovery device system for lithium precipitation mother liquor

Abstract

The utility model provides a comprehensive recovery device system for lithium precipitation mother liquor, which comprises a cooling unit, a primary nanofiltration unit, a secondary nanofiltration unit, a lithium adsorption and desorption unit, a lithium refining unit and a lithium precipitation unit, the comprehensive recovery device system has the advantages of no pollution, few chemicals, high recovery rate and good quality of the recovered product in the recovery process, the comprehensive recovery device system can utilize the existing equipment, the investment is saved, the lithium precipitation unit and the lithium adsorption and desorption unit can also utilize the existing equipment, the lithium concentration unit can also utilize a reverse osmosis device of a lithium refining workshop, and the investment is low.

Description

Technical Field

[0001] The utility model belongs to the technical field of resource recovery, and in particular relates to a comprehensive recovery device system for lithium precipitation mother liquor. Background Art

[0002] Lithium carbonate is widely used in aerospace, military, ceramics, glass, batteries, medical and other industries. With the rise of new energy in recent years, the demand for lithium carbonate has been increasing. There are great development opportunities for lithium extraction from salt lakes.

[0003] At present, the mainstream process of extracting lithium from salt lakes is adsorption. After the brine is adsorbed by lithium adsorbent, it is analyzed with fresh water to obtain qualified liquid. The qualified liquid is then removed and concentrated to obtain a lithium refined liquid with a high concentration and purity. The lithium refined liquid is added with saturated sodium carbonate to form lithium carbonate precipitation at about 80°C. After the lithium refined liquid is precipitated with lithium, the remaining lithium precipitation mother liquor still contains a high concentration of Li + But due to Na + and CO3 2- The content is very high, making it difficult to recycle the lithium precipitation mother liquor.

[0004] At present, the traditional methods for treating lithium precipitate mother liquor include: (1) adding hydrogen fluoride to lithium precipitate mother liquor to produce lithium fluoride, the lithium extraction rate is only about 70%, and the lithium extraction mother liquor contains a large amount of fluoride ions, which puts great pressure on the environment. (2) Preparation of battery-grade lithium dihydrogen phosphate: CN102351160BA undergoes preliminary lithium extraction and deep lithium extraction, and then adds phosphoric acid to generate lithium dihydrogen phosphate solution, which is evaporated and concentrated, cooled and crystallized, centrifuged, saturated washed and dried to obtain lithium dihydrogen phosphate. This method is complex and energy-intensive, and is mostly a by-product of the lithium carbonate production process.

[0005] CN117965906A discloses a method for recycling lithium from waste ternary lithium batteries, which includes adding an extractant to a lithium-precipitated mother liquor to extract lithium, separating a lithium-containing extractant, and then stripping lithium, and continuing to add carbonate to the stripping solution to precipitate lithium carbonate. The extraction process is used for recycling, and the extractant has a certain loss during the extraction-stripping process and needs to be replenished regularly. The extractant has a complex composition and is easy to pollute the environment. The extraction-stripping process consumes a large amount of acid and alkali, and the extractant is easily ineffective if not handled carefully, and the processing cost is high.

[0006] The lithium precipitation mother liquor recovery method described in the above scheme has the problems of difficulty in recovering the lithium precipitation mother liquor, high pollution and high reagent consumption, and is difficult to be applied in industrial production. Utility Model Content

[0007] In view of the shortcomings of the prior art, the utility model aims to provide a comprehensive recovery device system for lithium precipitation mother liquor, which greatly reduces the consumption of reagents in the recovery process, and achieves a pollution-free, low-reagent, high-recovery and high-quality method for recovering lithium precipitation mother liquor. The lithium recovery rate in the lithium precipitation mother liquor can reach more than 93%, and CO3 in the lithium precipitation mother liquor can be recovered at the same time. 2- The product lithium carbonate meets the requirements of battery-grade lithium carbonate, with a purity of over 99.5%.

[0008] To achieve this purpose, the utility model adopts the following technical solutions:

[0009] The utility model provides a comprehensive recovery device system for lithium precipitation mother liquor, including a cooling unit, a primary nanofiltration unit, a secondary nanofiltration unit, a lithium adsorption and analysis unit, a lithium refining unit and a lithium precipitation unit;

[0010] The cooling unit comprises a cooling device;

[0011] A raw material box is arranged between the cooling unit and the primary nanofiltration unit;

[0012] The primary nanofiltration unit comprises a primary nanofiltration device, the primary nanofiltration device comprises a divalent ion nanofiltration membrane, a lithium precipitation mother liquor feed port, a primary nanofiltration water production discharge port and a primary nanofiltration concentrated water discharge port, the lithium precipitation mother liquor feed port is connected to a raw material box, the primary nanofiltration water production discharge port and the primary nanofiltration concentrated water discharge port are arranged on the primary nanofiltration device on a side away from the lithium precipitation mother liquor feed port, and a divalent ion nanofiltration membrane is arranged between the lithium precipitation mother liquor feed port and the primary nanofiltration water production discharge port and the primary nanofiltration concentrated water discharge port;

[0013] The secondary nanofiltration unit comprises a secondary nanofiltration device, the secondary nanofiltration device comprises a divalent ion nanofiltration membrane, a primary nanofiltration produced water feed inlet, a secondary nanofiltration produced water discharge port and a secondary nanofiltration concentrated water discharge port, the primary nanofiltration produced water feed inlet is connected to the primary nanofiltration produced water discharge port, the secondary nanofiltration produced water discharge port and the secondary nanofiltration concentrated water discharge port are arranged on the secondary nanofiltration device on a side away from the primary nanofiltration produced water feed inlet, and a divalent ion nanofiltration membrane is arranged between the primary nanofiltration produced water feed inlet and the secondary nanofiltration produced water discharge port and the secondary nanofiltration concentrated water discharge port;

[0014] The lithium adsorption and analysis unit comprises a lithium adsorption device and a lithium analysis device connected to each other;

[0015] The lithium refining unit comprises an evaporation and concentration device, and a lithium refined liquid discharge port is arranged on the side of the evaporation and concentration device away from the lithium adsorption device;

[0016] The primary nanofiltration concentrated water discharge port and the lithium refined liquid discharge port are independently connected to the lithium precipitation unit.

[0017] The main function of the primary sodium filter unit of the utility model is to separate CO3 2- The cooled lithium precipitation mother liquor is separated into primary sodium filtration concentrated water and primary sodium filtration produced water. The primary sodium filtration concentrated water contains a high concentration of CO3 2- , reaching 60g / L or more. The primary sodium filtration concentrated water forms a lithium carbonate-saturated sodium carbonate solution after adding sodium carbonate, which can be used for lithium precipitation. The secondary sodium filtration unit converts the CO3 in the primary sodium filtration produced by the primary nanofiltration unit into 2- Then separate into secondary sodium filtration produced water and secondary sodium filtration concentrated water. The secondary sodium filtration produced water contains CO3 2- Drop to below 0.2g / L, the secondary sodium filtration concentrated water CO3 2- It is concentrated to about 20g / L. The lithium adsorption and analysis unit is mainly a lithium adsorbent, which adsorbs the lithium in the lithium-containing brine into the adsorbent, and analyzes the adsorbed lithium through pure water washing. After the secondary sodium filtration water enters the adsorption stage, the lithium in the secondary sodium filtration water is adsorbed into the interior of the adsorbent by the adsorbent, and the secondary sodium filtration water is adsorbed to form a tail liquid that is discharged. The adsorbent saturated with adsorption is then washed with pure water to wash out the lithium to form a qualified liquid. The lithium precipitation unit reacts the lithium refined liquid with the lithium carbonate-saturated sodium carbonate to form a lithium carbonate precipitate at high temperature. The lithium carbonate-saturated sodium carbonate solution is configured using the primary sodium filtration concentrated water.

[0018] As a preferred technical solution of the present utility model, the cooling device includes a cooling tower and / or a heat exchanger.

[0019] As a preferred technical solution of the utility model, the cooling device is provided with a feed port for introducing the lithium precipitation mother solution and a discharge port for discharging the cooled lithium precipitation mother solution.

[0020] As a preferred technical solution of the utility model, a dialysis nanofiltration device is arranged between the primary nanofiltration concentrated water outlet and the lithium precipitation unit.

[0021] As an optimal technical solution of the present utility model, the dialysis nanofiltration device includes a dialysis nanofiltration feed port, a pure water feed port, a dialysis nanofiltration produced water outlet port and a dialysis nanofiltration concentrated water outlet port, and the dialysis nanofiltration feed port and the pure water feed port are independently arranged on one side of the dialysis nanofiltration device.

[0022] As a preferred technical solution of the utility model, the dialysis nanofiltration water outlet and the dialysis nanofiltration concentrated water outlet are independently arranged on the dialysis nanofiltration device at a side away from the dialysis nanofiltration feed port and the pure water feed port.

[0023] In the utility model, a dialysis nanofiltration device is arranged between the first-stage nanofiltration concentrate outlet and the lithium precipitation unit. The first-stage nanofiltration concentrate flowing out of the first-stage nanofiltration concentrate outlet enters the dialysis nanofiltration device through the dialysis nanofiltration feed port. The carbonate ions recovered through the dialysis nanofiltration are purer, but pure water needs to be introduced through the pure water feed port. If the dialysis times are too many, the lithium concentration in the produced water is too low and has no recovery value.

[0024] As a preferred technical solution of the utility model, the dialysis nanofiltration feed port is connected to the primary nanofiltration concentrated water discharge port of the primary nanofiltration device.

[0025] As a preferred technical solution of the utility model, the dialysis nanofiltration water outlet is connected to the primary nanofiltration water inlet.

[0026] As a preferred technical solution of the utility model, the dialysis nanofiltration concentrated water outlet is connected to a lithium precipitation unit.

[0027] As a preferred technical solution of the utility model, a pH adjustment unit is arranged between the secondary nanofiltration device and the lithium adsorption and analysis unit.

[0028] As a preferred technical solution of the utility model, the secondary nanofiltration concentrated water outlet of the secondary nanofiltration device is connected to the raw material box.

[0029] As a preferred technical solution of the utility model, the lithium adsorption device includes a tail liquid discharge device and a lithium adsorption liquid discharge port.

[0030] As a preferred technical solution of the utility model, the tail liquid discharge device and the lithium adsorption liquid discharge port are independently arranged on the side of the lithium adsorption device away from the secondary nanofiltration device.

[0031] As a preferred technical solution of the utility model, the lithium analysis device includes a lithium adsorption liquid feed port, a lithium analysis liquid discharge port and a pure water feed port.

[0032] As a preferred technical solution of the utility model, the lithium adsorption liquid feed port is connected to the lithium adsorption liquid discharge port of the lithium adsorption device.

[0033] As a preferred technical solution of the utility model, the lithium analysis solution outlet and the pure water feed port are independently arranged on the lithium analysis device at a side away from the lithium adsorption solution feed port.

[0034] As a preferred technical solution of the utility model, a pure water recovery device system is arranged between the lithium adsorption and analysis unit and the lithium refining unit.

[0035] As a preferred technical solution of the present utility model, the pure water recovery device system includes a reverse osmosis device.

[0036] As a preferred technical solution of the utility model, the reverse osmosis device includes a lithium analysis solution feed port, a reverse osmosis produced water discharge port and a reverse osmosis concentrated water discharge port.

[0037] As a preferred technical solution of the present utility model, the lithium analysis solution feed port is connected to the lithium analysis solution discharge port of the lithium analysis device.

[0038] As a preferred technical solution of the utility model, the reverse osmosis produced water outlet and the reverse osmosis concentrated water outlet are independently arranged on the reverse osmosis device at a side away from the lithium analysis solution feed port.

[0039] As a preferred technical solution of the utility model, the pure water recovery device system also includes a primary pure water reverse osmosis device and a secondary pure water reverse osmosis device.

[0040] As a preferred technical solution of the utility model, the primary pure water reverse osmosis device includes a reverse osmosis water production feed inlet and a primary pure water reverse osmosis water production outlet.

[0041] As a preferred technical solution of the utility model, the two-stage pure water reverse osmosis device includes a first-stage pure water reverse osmosis water inlet and a second-stage pure water reverse osmosis water outlet.

[0042] As a preferred technical solution of the utility model, the primary pure water reverse osmosis water outlet is respectively connected to the primary pure water reverse osmosis water inlet and the lithium analysis solution feed inlet of the secondary pure water reverse osmosis device.

[0043] As a preferred technical solution of the utility model, the secondary pure water reverse osmosis water outlet is respectively connected to the primary pure water reverse osmosis water inlet and the lithium analysis device.

[0044] As a preferred technical solution of the utility model, the evaporation concentration device also includes a reverse osmosis concentrated water feed port and a condensed water discharge port.

[0045] As a preferred technical solution of the utility model, the reverse osmosis concentrated water feed port is connected to the reverse osmosis concentrated water discharge port of the reverse osmosis device.

[0046] As a preferred technical solution of the present utility model, the condensed water outlet is connected to the reverse osmosis water outlet of the reverse osmosis device.

[0047] As a preferred technical solution of the present utility model, the lithium sinking unit includes a lithium sinking device.

[0048] As a preferred technical solution of the utility model, the lithium refined liquid discharge port of the evaporation concentration device and the primary nanofiltration concentrated water discharge port of the primary nanofiltration device are respectively connected to the lithium precipitation device.

[0049] As a preferred technical solution of the utility model, a sodium hydroxide and sodium carbonate adding unit is arranged between the primary nanofiltration concentrated water discharge port and the lithium precipitation device.

[0050] Compared with the prior art, the beneficial effects of the utility model are:

[0051] (1) The comprehensive recovery device system of lithium precipitation mother liquor of the utility model reduces the consumption of reagents in the recovery process, achieves no pollution, less reagents, high recovery rate, and good product quality. The lithium recovery rate in lithium precipitation mother liquor can reach more than 93%, and CO3 in lithium precipitation mother liquor can be recovered at the same time. 2- The product lithium carbonate meets the requirements of battery-grade lithium carbonate, and the purity reaches more than 99.5%. The comprehensive recovery device system can use existing equipment to save investment. The lithium precipitation unit and lithium adsorption and analysis unit can also use existing equipment. Lithium concentration can also use the reverse osmosis device of the lithium refining workshop, which requires less investment.

[0052] (2) The lithium recovery in the comprehensive recovery device system of the utility model can be divided into two routes. One route is synchronized with carbonate recovery (i.e., sodium carbonate and sodium hydroxide are added to the primary nanofiltration concentrated water to precipitate lithium), accounting for about 35% of the total lithium recovery, and directly participates in the recovery in the form of Li2CO3, with a high recovery rate of up to 100%. The other route is recovered through an adsorption-analysis process, with a recovery rate of more than 90%. The comprehensive recovery rate of the two lines is more than 95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic diagram of the comprehensive recovery device system of the lithium precipitation mother liquor of the utility model, wherein 1 is a cooling unit, 2 is a raw material box, 3 is a primary nanofiltration unit, 3a is a primary sodium filtration concentrated water, 4 is a secondary nanofiltration unit, 4a is a secondary sodium filtration produced water, 4b is a secondary sodium filtration concentrated water, 5 is a lithium adsorption and analysis unit, 5-1 is a lithium adsorption device, 5-2 is a lithium analysis device, 5a is a lithium analysis solution, 6 is a lithium refining unit, 6a is a lithium refining solution, 6b is condensed water, 7 is a lithium precipitation unit, 8 is a dialysis nanofiltration device, 8a is dialysis nanofiltration water, 8b is dialysis nanofiltration concentrated water, 9 is a reverse osmosis device, 9a is reverse osmosis water, 9-1 is a primary pure water reverse osmosis device, 9-1a is primary pure water reverse osmosis water, 9-2 is a secondary pure water reverse osmosis device, 9-2a is secondary pure water reverse osmosis water, 9-2b is secondary pure water reverse osmosis concentrated water, 10 is a pH adjustment unit, and 11 is a sodium hydroxide and sodium carbonate adding unit. DETAILED DESCRIPTION

[0054] It should be understood that, in the description of the present utility model, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, which is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0055] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0056] The technical solution of the utility model is further explained below with reference to the accompanying drawings and through specific implementation methods.

[0057] In a specific embodiment, the utility model provides a Figure 1 The comprehensive recovery device system of lithium precipitation mother liquor shown includes a cooling unit 1, a primary nanofiltration unit 3, a secondary nanofiltration unit 4, a lithium adsorption and analysis unit 5, a lithium refining unit 6 and a lithium precipitation unit 7, and a raw material box 2 is arranged between the cooling unit 1 and the primary nanofiltration unit 3;

[0058] The cooling unit comprises a cooling device;

[0059] A raw material box 2 is arranged between the cooling unit 1 and the primary nanofiltration unit 3;

[0060] The primary nanofiltration unit 3 includes a primary nanofiltration device, which includes a divalent ion nanofiltration membrane, a lithium precipitation mother liquor feed port, a primary nanofiltration water production outlet, and a primary nanofiltration concentrated water outlet. The lithium precipitation mother liquor feed port is connected to a raw material box, and the primary nanofiltration water production outlet and the primary nanofiltration concentrated water outlet are arranged on the primary nanofiltration device on a side away from the lithium precipitation mother liquor feed port. A divalent ion nanofiltration membrane is arranged between the lithium precipitation mother liquor feed port and the primary nanofiltration water production outlet and the primary nanofiltration concentrated water outlet.

[0061] The secondary nanofiltration unit 4 includes a secondary nanofiltration device, which includes a divalent ion nanofiltration membrane, a primary nanofiltration water production feed port, a secondary nanofiltration water production discharge port, and a secondary nanofiltration concentrated water discharge port. The primary nanofiltration water production feed port is connected to the primary nanofiltration water production discharge port, and the secondary nanofiltration water production discharge port and the secondary nanofiltration concentrated water discharge port are arranged on the secondary nanofiltration device on a side away from the primary nanofiltration water production feed port. A divalent ion nanofiltration membrane is arranged between the primary nanofiltration water production feed port and the secondary nanofiltration water production discharge port and the secondary nanofiltration concentrated water discharge port.

[0062] The lithium adsorption and analysis unit 5 comprises a lithium adsorption device and a lithium analysis device connected to each other;

[0063] The lithium refining unit 6 includes an evaporation and concentration device, and the evaporation and concentration device includes a lithium refined liquid discharge port;

[0064] The primary nanofiltration concentrated water outlet and the lithium refined liquid outlet are independently connected to the lithium precipitation unit 7 .

[0065] The main function of the primary sodium filter unit of the utility model is to separate CO3 2- The cooled lithium precipitation mother liquor is separated into primary sodium filtration concentrated water and primary sodium filtration produced water. The primary sodium filtration concentrated water contains a high concentration of CO3 2- , reaching 60g / L or more. The primary sodium filtration concentrated water forms a lithium carbonate-saturated sodium carbonate solution after adding sodium carbonate, which can be used for lithium precipitation. The secondary sodium filtration unit converts the CO3 in the primary sodium filtration produced by the primary nanofiltration unit into 2- Then separate into secondary sodium filtration produced water and secondary sodium filtration concentrated water. The secondary sodium filtration produced water contains CO3 2- Drop to below 0.2g / L, the secondary sodium filtration concentrated water CO3 2-It is concentrated to about 20g / L. The lithium adsorption and analysis unit is mainly a lithium adsorbent, which adsorbs the lithium in the lithium-containing brine into the adsorbent, and analyzes the adsorbed lithium through pure water washing. After the secondary sodium filtration water enters the adsorption stage, the lithium in the secondary sodium filtration water is adsorbed into the interior of the adsorbent by the adsorbent, and the secondary sodium filtration water is adsorbed to form a tail liquid that is discharged. The adsorbent saturated with adsorption is then washed with pure water to wash out the lithium to form a qualified liquid. The lithium precipitation unit reacts the lithium refined liquid with the lithium carbonate-saturated sodium carbonate to form a lithium carbonate precipitate at high temperature. The lithium carbonate-saturated sodium carbonate solution is configured using the primary sodium filtration concentrated water.

[0066] The comprehensive recovery device system of lithium precipitation mother liquor described in the utility model recovers almost all carbonate radicals in lithium precipitation mother liquor through the primary sodium filter unit and the secondary sodium filter unit, removes carbonate radicals with pH buffering effect in the lithium precipitation mother liquor, and only needs a small amount of hydrochloric acid to adjust the pH of the lithium precipitation mother liquor to neutrality, thereby reducing the amount of acid used. Since the pH value of the lithium precipitation mother liquor itself is above 12, the sodium filtration separation process does not change the pH value of the lithium precipitation mother liquor itself, and the pH value of the primary sodium filtration concentrated water is also above 12, so the comprehensive recovery device system uses less sodium hydroxide, thereby reducing the amount of alkali used. The comprehensive recovery device system can recover lithium and carbonate radicals in the lithium precipitation mother liquor, reduce the discharge of the lithium precipitation mother liquor, and reduce pollution. Since the lithium precipitation mother liquor is strongly alkaline, direct discharge will destroy the fragile ecosystem of the salt lake. The comprehensive recovery device system described in the utility model only needs to discharge a small amount of tail liquid (main component NaCl, neutral, pollution-free), thereby greatly reducing pollutant discharge.

[0067] Furthermore, the cooling device includes a cooling tower and / or a heat exchanger.

[0068] Furthermore, the cooling device is provided with a feed port for introducing the lithium precipitation mother solution and a discharge port for discharging the cooled lithium precipitation mother solution.

[0069] Furthermore, a dialysis nanofiltration device is arranged between the primary nanofiltration concentrated water outlet and the lithium precipitation unit.

[0070] Furthermore, the dialysis nanofiltration device comprises a dialysis nanofiltration feed port, a pure water feed port, a dialysis nanofiltration produced water discharge port and a dialysis nanofiltration concentrated water discharge port.

[0071] Furthermore, the dialysis nanofiltration feed port and the pure water feed port are independently arranged on one side of the dialysis nanofiltration device.

[0072] Furthermore, the dialysis nanofiltration produced water outlet and the dialysis nanofiltration concentrated water outlet are independently arranged on the dialysis nanofiltration device at a side away from the dialysis nanofiltration feed inlet and the pure water feed inlet.

[0073] In the utility model, a dialysis nanofiltration device is arranged between the first-stage nanofiltration concentrate outlet and the lithium precipitation unit. The first-stage nanofiltration concentrate flowing out of the first-stage nanofiltration concentrate outlet enters the dialysis nanofiltration device through the dialysis nanofiltration feed port. The carbonate ions recovered through the dialysis nanofiltration are purer, but pure water needs to be introduced through the pure water feed port. If the dialysis times are too many, the lithium concentration in the produced water is too low and has no recovery value.

[0074] Furthermore, the dialysis nanofiltration feed port is connected to the primary nanofiltration concentrated water discharge port of the primary nanofiltration device.

[0075] Furthermore, the dialysis nanofiltration water output port is connected to the primary nanofiltration water output port.

[0076] Furthermore, the dialysis nanofiltration concentrated water outlet is connected to a lithium precipitation unit.

[0077] Furthermore, a pH adjustment unit is provided between the secondary nanofiltration device and the lithium adsorption and analysis unit.

[0078] Furthermore, the secondary nanofiltration concentrate outlet of the secondary nanofiltration device is connected to the raw material box.

[0079] Furthermore, the lithium adsorption device comprises a tail liquid discharge device and a lithium adsorption liquid discharge port.

[0080] Furthermore, the tail liquid discharge device and the lithium adsorption liquid discharge port are independently arranged on a side of the lithium adsorption device away from the secondary nanofiltration device.

[0081] Furthermore, the lithium analysis device comprises a lithium adsorption solution feed port, a lithium analysis solution discharge port and a pure water feed port.

[0082] Furthermore, the lithium adsorption liquid feed port is connected to the lithium adsorption liquid discharge port of the lithium adsorption device.

[0083] Furthermore, the lithium analysis solution outlet and the pure water feed port are independently arranged on the lithium analysis device at a side away from the lithium adsorption solution feed port.

[0084] Furthermore, a pure water recovery device system is arranged between the lithium adsorption and analysis unit and the lithium refining unit.

[0085] Furthermore, the pure water recovery device system includes a reverse osmosis device.

[0086] The reverse osmosis device of the utility model mainly concentrates the qualified liquid with low concentration. After the qualified liquid is concentrated by reverse osmosis, the lithium content is higher than 6g / L, and a very low concentration of RO produced water is formed. The MVR further concentrates the RO concentrated water by evaporation, and the condensed water generated by the MVR is mixed with the RO produced water for reuse.

[0087] Furthermore, the reverse osmosis device comprises a lithium analysis solution feed port, a reverse osmosis produced water discharge port and a reverse osmosis concentrated water discharge port.

[0088] Furthermore, the lithium analysis solution feed port is connected to the lithium analysis solution discharge port of the lithium analysis device.

[0089] Furthermore, the reverse osmosis produced water outlet and the reverse osmosis concentrated water outlet are independently arranged on a side of the reverse osmosis device away from a lithium analysis solution feed port.

[0090] Furthermore, the pure water recovery device system also includes a primary pure water reverse osmosis device and a secondary pure water reverse osmosis device.

[0091] Furthermore, the primary pure water reverse osmosis device includes a reverse osmosis water feed inlet and a primary pure water reverse osmosis water outlet.

[0092] Furthermore, the secondary pure water reverse osmosis device includes a primary pure water reverse osmosis water inlet and a secondary pure water reverse osmosis water outlet.

[0093] Furthermore, the primary pure water reverse osmosis water outlet is respectively connected to the primary pure water reverse osmosis water inlet and the lithium analysis solution feed inlet of the secondary pure water reverse osmosis device.

[0094] Furthermore, the secondary pure water reverse osmosis water outlet is respectively connected to the primary pure water reverse osmosis water inlet and the lithium analysis device.

[0095] Furthermore, the evaporation concentration device also includes a reverse osmosis concentrated water feed port and a condensed water discharge port.

[0096] Furthermore, the reverse osmosis concentrated water feed port is connected to the reverse osmosis concentrated water discharge port of the reverse osmosis device.

[0097] Furthermore, the condensed water outlet is connected to the reverse osmosis water outlet of the reverse osmosis device.

[0098] Furthermore, the lithium deposition unit includes a lithium deposition device.

[0099] Furthermore, the lithium refined liquid discharge port of the evaporation concentration device and the primary nanofiltration concentrated water discharge port of the primary nanofiltration device are respectively connected to the lithium precipitation device.

[0100] Furthermore, a sodium hydroxide and sodium carbonate adding unit is arranged between the primary nanofiltration concentrated water discharge port and the lithium precipitation device.

[0101] The lithium recovery in the comprehensive recovery device system of the utility model can be divided into two routes. One route is synchronized with carbonate recovery (i.e., sodium carbonate and sodium hydroxide are added to the primary nanofiltration concentrated water to precipitate lithium), accounting for about 35% of the total lithium recovery, and directly participates in the recovery in the form of Li2CO3, with a high recovery rate of up to 100%. The other route is recovered through the adsorption-analysis process, and the recovery rate can reach more than 90%. The comprehensive recovery rate of the two lines is more than 95%.

[0102] Example 1

[0103] This embodiment provides a comprehensive recovery device system for lithium precipitation mother liquor, which comprises a cooling unit 1, a primary nanofiltration unit 3, a secondary nanofiltration unit 4, a lithium adsorption and analysis unit 5, a lithium refining unit 6 and a lithium precipitation unit 7, wherein a raw material box 2 is arranged between the cooling unit 1 and the primary nanofiltration unit 3;

[0104] The nanofiltration membranes in the primary nanofiltration unit 3 and the secondary nanofiltration unit 4 are both divalent ion nanofiltration membranes that can filter carbonate ions. The lithium precipitation mother liquor is cooled to 30°C by the cooling unit 1 and then enters the raw material box 2. The primary sodium filtration unit 3 removes CO3 in the lithium precipitation mother liquor. 2- Concentrate more than 3 times to obtain the primary sodium filtration concentrated water 3a containing Li + 、Na + and CO3 2- The pH value of the primary sodium filtration concentrated water 3a is about 12.5. The primary sodium filtration concentrated water 3a can be added with sodium carbonate to obtain a lithium carbonate-saturated sodium carbonate solution. The lithium carbonate-saturated sodium carbonate solution can provide CO3 for the lithium precipitation unit 2- , and can also provide a small amount of Li for the lithium sink unit + , achieving a small amount of Li + and most of CO3 2- of reuse.

[0105] The primary sodium filtration product water 3b is further separated by the secondary sodium filtration unit 4 to obtain secondary sodium filtration product water 4a and secondary sodium filtration concentrated water 4b. The secondary sodium filtration concentrated water 4b is separated from the CO3 in the lithium precipitation mother liquor. 2- The concentration is consistent and can be returned to the raw material box 2 to re-enter the device system. The secondary sodium filtration produces water 4a, and its CO3 2- The concentration is low and can reach below 0.2g / L.

[0106] Further, the primary nanofiltration concentrated water 3a obtained by the primary nanofiltration unit 3 can also enter the dialysis nanofiltration device 8, and the dialysis nanofiltration product water 8a obtained by the dialysis nanofiltration device 8 is mixed with the primary nanofiltration product water 3b and enters the secondary nanofiltration unit 4. The dialysis nanofiltration concentrated water 8b obtained by the dialysis nanofiltration device 8 enters the lithium precipitation unit 7 through the sodium hydroxide and sodium carbonate adding unit 11;

[0107] The secondary nanofiltration concentrated water 4b obtained by the secondary nanofiltration unit 4 reenters the raw material box, and the secondary sodium filtration produced water 4a obtained contains Li + 、Na + and Cl - , whose Na + The content is very high, reaching about 40g / L. The lithium content is relatively high, reaching about 1.5g / L, and the lithium-sodium ratio is very low. The secondary nanofiltration water 4a passes through the pH adjustment unit 10, and after adding acid to adjust the pH value to neutral, it enters the lithium adsorption device 5-1 of the lithium adsorption analysis unit 5. The obtained lithium adsorption liquid enters the lithium analysis device 5-2. The lithium adsorption device 5-1 is adsorbed by a lithium adsorbent to adsorb the lithium in the secondary sodium filtration water 4a into the adsorbent to form a saturated lithium adsorbent. After the secondary sodium filtration water 4a passes through the lithium adsorption device 5-1, a tail liquid is discharged, and the tail liquid contains a large amount of Na + and Cl - The lithium analysis device 5-2 washes the saturated lithium adsorbent with pure water to elute the lithium in the saturated lithium adsorbent to obtain a lithium analysis solution 5a, wherein the lithium content of the lithium analysis solution 5a is greater than 0.6 g / L and the lithium-sodium ratio is greater than 3:1.

[0108] The obtained lithium analysis solution 5a enters the reverse osmosis device 9, the obtained reverse osmosis product water 9a enters the primary pure water reverse osmosis device 9-1, the obtained primary pure water reverse osmosis product water 9-1a enters the secondary pure water reverse osmosis device 9-2, the obtained primary pure water reverse osmosis concentrated water 9-1b is mixed with the lithium analysis solution 5a, the secondary pure water reverse osmosis product water 9-2a obtained by the secondary pure water reverse osmosis device 9-2 is injected into the lithium analysis device 5-2 as pure water for lithium analysis, and the secondary pure water reverse osmosis concentrated water 9-2b obtained by the secondary pure water reverse osmosis device 9-2 is mixed with the reverse osmosis product water 9a;

[0109] The reverse osmosis product water 9b obtained by the reverse osmosis device 9 enters the lithium refining unit 6 for evaporation and concentration, and the obtained condensed water 6b is mixed with the reverse osmosis product water 9a to obtain a lithium refined liquid 6a, wherein the lithium content of the lithium refined liquid 6a is greater than 20g / L;

[0110] The lithium refined liquid 6a enters the lithium precipitation unit 7 and is added with the above-mentioned lithium carbonate-saturated sodium carbonate solution, and then sodium hydroxide is added to adjust the pH value to 12.5, and the temperature is increased to 80°C to form lithium carbonate precipitation. The lithium carbonate precipitation is then eluted and dried to obtain battery-grade lithium carbonate.

[0111] The applicant declares that the above is only a specific implementation method of the present utility model, but the protection scope of the present utility model is not limited thereto. The technicians in the relevant technical field should understand that any changes or substitutions that can be easily thought of by the technicians in the relevant technical field within the technical scope disclosed in the present utility model fall within the protection scope and disclosure scope of the present utility model.

Claims

1. A comprehensive recovery device system for lithium precipitation mother liquor, characterized in that: It includes a cooling unit, a primary nanofiltration unit, a secondary nanofiltration unit, a lithium adsorption and analysis unit, a lithium refining unit and a lithium precipitation unit; The cooling unit comprises a cooling device; A raw material box is arranged between the cooling unit and the primary nanofiltration unit; The primary nanofiltration unit comprises a primary nanofiltration device, the primary nanofiltration device comprises a divalent ion nanofiltration membrane, a lithium precipitation mother liquor feed port, a primary nanofiltration water production discharge port and a primary nanofiltration concentrated water discharge port, the lithium precipitation mother liquor feed port is connected to a raw material box, the primary nanofiltration water production discharge port and the primary nanofiltration concentrated water discharge port are arranged on the primary nanofiltration device on a side away from the lithium precipitation mother liquor feed port, and a divalent ion nanofiltration membrane is arranged between the lithium precipitation mother liquor feed port and the primary nanofiltration water production discharge port and the primary nanofiltration concentrated water discharge port; The secondary nanofiltration unit comprises a secondary nanofiltration device, the secondary nanofiltration device comprises a divalent ion nanofiltration membrane, a primary nanofiltration produced water feed inlet, a secondary nanofiltration produced water discharge port and a secondary nanofiltration concentrated water discharge port, the primary nanofiltration produced water feed inlet is connected to the primary nanofiltration produced water discharge port, the secondary nanofiltration produced water discharge port and the secondary nanofiltration concentrated water discharge port are arranged on the secondary nanofiltration device on a side away from the primary nanofiltration produced water feed inlet, and a divalent ion nanofiltration membrane is arranged between the primary nanofiltration produced water feed inlet and the secondary nanofiltration produced water discharge port and the secondary nanofiltration concentrated water discharge port; The lithium adsorption and analysis unit comprises a lithium adsorption device and a lithium analysis device connected to each other; The lithium refining unit comprises an evaporation and concentration device, and a lithium refined liquid discharge port is arranged on the side of the evaporation and concentration device away from the lithium adsorption device; The primary nanofiltration concentrated water discharge port and the lithium refined liquid discharge port are independently connected to the lithium precipitation unit.

2. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 1 is characterized in that: The cooling device comprises a cooling tower and / or a heat exchanger; The cooling device is provided with a feed port for introducing the lithium precipitation mother solution and a discharge port for discharging the cooled lithium precipitation mother solution.

3. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 1 is characterized in that: A dialysis nanofiltration device is arranged between the primary nanofiltration concentrated water outlet and the lithium precipitation unit.

4. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 3 is characterized in that: The dialysis nanofiltration device comprises a dialysis nanofiltration feed port, a pure water feed port, a dialysis nanofiltration produced water discharge port and a dialysis nanofiltration concentrated water discharge port, wherein the dialysis nanofiltration feed port and the pure water feed port are independently arranged on one side of the dialysis nanofiltration device, and the dialysis nanofiltration produced water discharge port and the dialysis nanofiltration concentrated water discharge port are independently arranged on the dialysis nanofiltration device away from the dialysis nanofiltration feed port and the pure water feed port; The dialysis nanofiltration feed port is connected to the primary nanofiltration concentrated water discharge port of the primary nanofiltration device; The dialysis nanofiltration water output port is connected to the primary nanofiltration water output port; The dialysis nanofiltration concentrated water outlet is connected to the lithium precipitation unit.

5. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 1, characterized in that: A pH adjustment unit is provided between the secondary nanofiltration device and the lithium adsorption and analysis unit; The secondary nanofiltration concentrated water outlet of the secondary nanofiltration device is connected to the raw material box.

6. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 1, characterized in that: The lithium adsorption device comprises a tail liquid discharge device and a lithium adsorption liquid discharge port; The tail liquid discharge device and the lithium adsorption liquid discharge port are independently arranged on a side of the lithium adsorption device away from the secondary nanofiltration device; The lithium analysis device comprises a lithium adsorption liquid feed port, a lithium analysis liquid discharge port and a pure water feed port; The lithium adsorption liquid feed port is connected to the lithium adsorption liquid discharge port of the lithium adsorption device; The lithium analysis solution outlet and the pure water feed port are independently arranged on the lithium analysis device at a side away from the lithium adsorption solution feed port.

7. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 6 is characterized in that: A pure water recovery device system is arranged between the lithium adsorption and analysis unit and the lithium refining unit; The pure water recovery device system includes a reverse osmosis device; The reverse osmosis device comprises a lithium analysis solution feed port, a reverse osmosis produced water discharge port and a reverse osmosis concentrated water discharge port; The lithium analysis solution feed port is connected to the lithium analysis solution discharge port of the lithium analysis device; The reverse osmosis produced water outlet and the reverse osmosis concentrated water outlet are independently arranged on a side of the reverse osmosis device away from a lithium analysis solution feed port.

8. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 7, characterized in that: The pure water recovery device system also includes a primary pure water reverse osmosis device and a secondary pure water reverse osmosis device; The primary pure water reverse osmosis device comprises a reverse osmosis water feed inlet and a primary pure water reverse osmosis water outlet; The secondary pure water reverse osmosis device comprises a primary pure water reverse osmosis water inlet and a secondary pure water reverse osmosis water outlet; The primary pure water reverse osmosis water outlet is respectively connected to the primary pure water reverse osmosis water inlet and the lithium analysis solution feed inlet of the secondary pure water reverse osmosis device; The secondary pure water reverse osmosis water outlet is connected to the primary pure water reverse osmosis water inlet and the lithium analysis device respectively.

9. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 7, characterized in that: The evaporation concentration device also includes a reverse osmosis concentrated water feed port and a condensed water discharge port; The reverse osmosis concentrated water feed port is connected to the reverse osmosis concentrated water discharge port of the reverse osmosis device; The condensed water outlet is connected to the reverse osmosis water outlet of the reverse osmosis device.

10. The comprehensive recovery device system of lithium precipitation mother liquor according to claim 1, characterized in that: The lithium sinking unit comprises a lithium sinking device; The lithium refined liquid discharge port of the evaporation concentration device and the primary nanofiltration concentrated water discharge port of the primary nanofiltration device are respectively connected to the lithium precipitation device; A sodium hydroxide and sodium carbonate adding unit is arranged between the primary nanofiltration concentrated water discharge port and the lithium precipitation device.

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