A production system for brine treatment and for the preparation of lithium carbonate

Abstract

This invention relates to the field of lithium carbonate preparation from brine. It addresses the problem of organic matter accumulation and difficulty in treatment when directly producing lithium carbonate from brine, ultimately affecting product quality. This invention provides a production system for brine treatment and lithium carbonate preparation, including a brine transfer tank, a high-pressure pump, a heating unit, a wet oxidation unit, a separator, a purification unit, a sodium precipitation unit, and a lithium precipitation unit. The brine transfer tank, high-pressure pump, heating unit, and wet oxidation unit are sequentially connected. The feed end of the separator is connected to the discharge end of the wet oxidation unit; the discharge end of the separator is connected to the feed end of the purification unit; the purification unit is connected to the sodium precipitation unit; and the sodium precipitation unit is connected to the lithium precipitation unit. This invention avoids the continuous accumulation of organic matter in the lithium carbonate preparation system, thereby preventing the organic matter from affecting the subsequent lithium separation efficiency and adversely affecting the quality of the lithium carbonate product.

Description

Technical Field

[0001] This utility model relates to the field of brine preparation of lithium carbonate, and more specifically, to a production system for brine treatment and preparation of lithium carbonate. Background Technology

[0002] Salt lake brine is an important source of lithium resources. Its composition is complex, containing not only lithium but also various elements such as sodium, potassium, magnesium, and boron, as well as organic matter (such as colloids, microorganisms, and humic acid). These organic substances can affect the separation efficiency of subsequent lithium products, equipment operation, and even product quality. Therefore, when using brine as a raw material to prepare lithium products, it is usually necessary to treat the brine for organic matter. Current technology generally uses hypochlorous acid as an oxidant to break down the molecular structure of organic matter, thereby decomposing it. However, using hypochlorous acid introduces new impurities or residues, such as hypochlorites, which are difficult to remove in the subsequent lithium carbonate preparation process, thus affecting the purity and quality of the product. Furthermore, hypochlorous acid treatment alters the chemical composition and properties of the brine, such as pH and ion concentration. These changes can affect the lithium carbonate preparation process, such as precipitation conditions and filtration efficiency, further increasing production difficulty and energy consumption.

[0003] Based on the above description, there is an urgent need for a brine treatment and production system for preparing lithium carbonate. Utility Model Content

[0004] The purpose of this invention is to provide a production system for preparing lithium carbonate from brine, which aims to solve the technical problem that organic matter accumulates and is difficult to handle when directly producing lithium carbonate from brine, ultimately affecting product quality.

[0005] The embodiments of this utility model are achieved through the following technical solutions:

[0006] A production system for treating brine and preparing lithium carbonate includes a brine transfer tank, a high-pressure pump, a heating unit, a wet oxidation unit, a separator, a purification unit, a sodium precipitation unit, and a lithium precipitation unit. The brine transfer tank, high-pressure pump, heating unit, and wet oxidation unit are connected in sequence. The feed end of the separator is connected to the discharge end of the wet oxidation unit. The discharge end of the separator is connected to the feed end of the purification unit. The purification unit is connected to the sodium precipitation unit. The sodium precipitation unit is connected to the lithium precipitation unit.

[0007] Preferably, the heating unit includes a preheater assembly and a heater; the discharge end of the high-pressure pump is connected to the feed end of the preheater assembly; the discharge end of the preheater assembly is connected to the heater; and the discharge end of the heater is connected to the feed end of the wet oxidation unit.

[0008] Preferably, the wet oxidation unit includes an oxygen supply mechanism and a wet oxidation reaction tower; the oxygen supply mechanism is connected to the bottom of the wet oxidation reaction tower; and the discharge end of the heater is connected to the bottom of the wet oxidation reaction tower.

[0009] Preferably, the top of the wet oxidation reaction tower is connected to the inlet of a steam generator; the outlet of the steam generator is connected to the preheater group; and the preheater group is connected to the feed end of the separator.

[0010] Preferably, the steam generator is connected to the shell side of the preheater group; the high-pressure pump is connected to the tube side of the preheater group.

[0011] Preferably, a condenser is provided between the preheater group and the separator.

[0012] Preferably, the discharge end of the condenser is connected to the separator; the top of the separator is connected to a tail gas absorption tower; and the discharge end of the separator is connected to the impurity removal unit.

[0013] Preferably, the feed end of the impurity removal unit is connected to a sodium sulfate mother liquor feed pipe.

[0014] Preferably, the discharge end of the impurity removal unit is connected to a filtration unit; the slag discharge end of the filtration unit is connected to a washing unit; and the liquid discharge end of the washing unit is connected to the feed end of the impurity removal unit.

[0015] The technical solution of this utility model embodiment has at least the following advantages and beneficial effects:

[0016] This invention employs a high-pressure pump, heating unit, wet oxidation unit, separator, etc., to pretreat the brine for organic matter, thereby preventing the continuous accumulation of organic matter in the lithium carbonate preparation system. This avoids the impact of organic matter on the subsequent lithium separation efficiency and prevents adverse effects on the quality of lithium carbonate products (such as particle size, color, solubility, etc.). Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the device system of this utility model;

[0018] Figure 2 This is a schematic diagram of the system flow of this utility model;

[0019] Figure 3 for Figure 2 A schematic diagram of the connection of the middle part of the device.

[0020] Icons: 1-Brine transfer tank, 2-High pressure pump, 3-Heating unit, 31-Preheater group, 32-Heater, 4-Wet oxidation unit, 41-Oxygen supply mechanism, 42-Wet oxidation reaction tower, 5-Separator, 6-Impurity removal unit, 61-Reaction vessel, 7-Sodium precipitation unit, 8-Lithium precipitation unit, 9-Condenser, 10-Tail gas absorption tower, 11-Sodium sulfate mother liquor feed pipe, 12-Filter unit, 13-Agitation and washing unit, 14-Steam generator, 15-Brine buffer tank, 16-Transfer tank. Detailed Implementation

[0021] The specific implementation method is described below with reference to the accompanying drawings.

[0022] Example 1

[0023] Please see Figures 1 to 3 The present invention provides the following technical solution: a production system for brine treatment and preparation of lithium carbonate, which is suitable for situations where the brine is pretreated with organic matter before preparing lithium carbonate.

[0024] Specifically, such as Figures 1 to 3 As shown, a production system for brine treatment and lithium carbonate preparation includes a brine transfer tank 1, a high-pressure pump 2, a heating unit 3, a wet oxidation unit 4, a separator 5, a purification unit 6, a sodium precipitation unit 7, and a lithium precipitation unit 8. The brine transfer tank 1, high-pressure pump 2, heating unit 3, and wet oxidation unit 4 are connected in sequence. The feed end of the separator 5 is connected to the discharge end of the wet oxidation unit 4. The discharge end of the separator 5 is connected to the feed end of the purification unit 6. The purification unit 6 is connected to the sodium precipitation unit 7. The sodium precipitation unit 7 is connected to the lithium precipitation unit 8.

[0025] In this embodiment, natural brine is first introduced into the brine transfer tank 1, then pressurized by the high-pressure pump 2 and pumped to the heating unit 3 for heating. After heating, it is pumped into the wet oxidation unit 4 for oxidation reaction to oxidize and decompose the organic matter in the brine. It is then further introduced into the separator 5 to separate the residual oxygen and other exhaust gases. The brine after organic matter treatment is introduced into the impurity removal unit 6 for impurity removal, then into the sodium precipitation unit 7 for sodium chloride precipitation separation, and finally into the lithium precipitation unit 8 for lithium carbonate preparation.

[0026] Unlike using natural brine directly as a raw material to prepare lithium carbonate, this embodiment pre-treats organic matter, which can prevent the continuous accumulation of organic matter in the lithium carbonate preparation system. This avoids the impact of organic matter on the subsequent lithium separation efficiency and prevents adverse effects on the quality of lithium carbonate products (such as particle size, color, solubility, etc.).

[0027] Specifically, such as Figure 1As shown, the heating unit 3 includes a preheater group 31 and a heater 32; the discharge end of the high-pressure pump 2 is connected to the feed end of the preheater group 31; the discharge end of the preheater group 31 is connected to the heater 32; and the discharge end of the heater 32 is connected to the feed end of the wet oxidation unit 4.

[0028] In this embodiment, the preheater group 31 uses multiple series-connected shell and tube preheater groups 31 for heating. The brine, pressurized by the high-pressure pump 2, flows through the tube side, while the heat exchange medium flows through the shell side. After preheating, the brine passes through the heater 32 again.

[0029] Specifically, such as Figure 1 As shown, the wet oxidation unit 4 includes an oxygen supply mechanism 41 and a wet oxidation reaction tower 42; the oxygen supply mechanism 41 is connected to the bottom of the wet oxidation reaction tower 42; the discharge end of the heater 32 is connected to the bottom of the wet oxidation reaction tower 42.

[0030] In this embodiment, the oxygen supply mechanism 41 uses a liquid oxygen storage tank to directly supply liquid oxygen as an oxidant, or it uses an oxygen generator or the like to supply oxygen as an oxidant.

[0031] In this embodiment, the reaction conditions in the wet oxidation reaction tower 42 are: pressure 6MPa, temperature 260℃.

[0032] Specifically, such as Figure 1 As shown, the top of the wet oxidation reaction tower 42 is connected to the inlet end of a steam generator 14; the outlet end of the steam generator 14 is connected to the preheater assembly 31; the preheater assembly 31 is connected to the feed end of the separator 5. The shell side of the steam generator 14 is connected to the preheater assembly 31; the high-pressure pump 2 is connected to the tube side of the preheater assembly 31. A condenser 9 is provided between the preheater assembly 31 and the separator 5.

[0033] In this embodiment, the steam generator 14 further heats up the vaporized brine and uses it as a heat exchange medium in the shell side of the preheater group 31 to preheat the brine that will be introduced later. The brine is then further condensed and recovered by the condenser 9, which effectively saves production energy consumption.

[0034] Specifically, such as Figure 1 As shown, the discharge end of the condenser 9 is connected to the separator 5; the top of the separator 5 is connected to the tail gas absorption tower 10; and the discharge end of the separator 5 is connected to the impurity removal unit 6.

[0035] In this embodiment, after the brine is condensed by the condenser 9, it is introduced into the separator 5 for gas-liquid separation, and then passed through the tail gas absorption tower 10 to absorb the tail gas generated after the decomposition of organic matter, namely carbon dioxide, using sodium hydroxide solution as the absorbent.

[0036] Specifically, such as Figure 2 and Figure 3 As shown, the feed end of the impurity removal unit 6 is connected to the sodium sulfate mother liquor feed pipe 11.

[0037] In this embodiment, the brine treated with organic matter is transferred to the brine buffer tank 15 via the transfer tank 16 for supplying the lithium carbonate production system.

[0038] In this embodiment, in the impurity removal unit 6, brine is introduced into the reaction vessel 61, and the mother liquor from the sodium sulfate production workshop is used to replace sodium sulfate and is introduced into the reaction vessel 61 for precipitation and calcium removal of the brine. This not only effectively utilizes the sodium sulfate in the mother liquor, but also allows sodium sulfate to be used directly as a product, effectively reducing production costs.

[0039] Specifically, such as Figure 1 As shown, the discharge end of the impurity removal unit 6 is connected to the filter unit 12; the slag discharge end of the filter unit 12 is connected to the agitation and washing unit 13; and the liquid discharge end of the agitation and washing unit 13 is connected to the feed end of the impurity removal unit 6.

[0040] In this embodiment, the filtration unit 12 adopts a multi-stage plate and frame filter press to filter the brine after precipitation and impurity removal. The filtered filtrate is sent to the sodium precipitation unit 7 for cooling and centrifugation. The clear liquid after centrifugation is passed into the lithium precipitation unit 8 for the preparation of lithium carbonate. The lithium precipitation unit 8 includes a lithium precipitation reactor. After the brine is passed into the lithium precipitation reactor, the prepared soda ash in the alkali tank is passed in. After the reaction, lithium carbonate is precipitated.

Claims

1. A production system for brine treatment and for the preparation of lithium carbonate, characterized by: The system includes a brine transfer tank (1), a high-pressure pump (2), a heating unit (3), a wet oxidation unit (4), a separator (5), a purification unit (6), a sodium precipitation unit (7), and a lithium precipitation unit (8); the brine transfer tank (1), the high-pressure pump (2), the heating unit (3), and the wet oxidation unit (4) are connected in sequence; the feed end of the separator (5) is connected to the discharge end of the wet oxidation unit (4); the discharge end of the separator (5) is connected to the feed end of the purification unit (6); the purification unit (6) is connected to the sodium precipitation unit (7); and the sodium precipitation unit (7) is connected to the lithium precipitation unit (8).

2. The brine treatment and lithium carbonate production system according to claim 1, characterized in that: The heating unit (3) includes a preheater group (31) and a heater (32); the discharge end of the high-pressure pump (2) is connected to the feed end of the preheater group (31); the discharge end of the preheater group (31) is connected to the heater (32); and the discharge end of the heater (32) is connected to the feed end of the wet oxidation unit (4).

3. The brine treatment and lithium carbonate production system according to claim 2, characterized in that: The wet oxidation unit (4) includes an oxygen supply mechanism (41) and a wet oxidation reaction tower (42); the oxygen supply mechanism (41) is connected to the bottom of the wet oxidation reaction tower (42); the discharge end of the heater (32) is connected to the bottom of the wet oxidation reaction tower (42).

4. The brine treatment and lithium carbonate production system according to claim 3, characterized in that: The top of the wet oxidation reaction tower (42) is connected to the inlet end of a steam generator (14); the outlet end of the steam generator (14) is connected to the preheater group (31); and the preheater group (31) is connected to the feed end of the separator (5).

5. The brine treatment and lithium carbonate production system according to claim 4, characterized in that: The steam generator (14) is connected to the shell side of the preheater group (31); the high-pressure pump (2) is connected to the tube side of the preheater group (31).

6. The brine treatment and lithium carbonate production system according to claim 5, characterized in that: A condenser (9) is provided between the preheater group (31) and the separator (5).

7. The brine treatment and lithium carbonate production system according to claim 6, characterized in that: The discharge end of the condenser (9) is connected to the separator (5); the top of the separator (5) is connected to the tail gas absorption tower (10); the discharge end of the separator (5) is connected to the impurity removal unit (6).

8. The production system for the treatment of brines and for the preparation of lithium carbonate according to any one of claims 1 to 7, characterized by the fact that: The feed end of the impurity removal unit (6) is connected to the sodium sulfate mother liquor feed pipe (11).

9. The brine treatment and lithium carbonate production system according to claim 8, characterized in that: The discharge end of the impurity removal unit (6) is connected to the filter unit (12); the slag discharge end of the filter unit (12) is connected to the agitation and washing unit (13); the liquid discharge end of the agitation and washing unit (13) is connected to the feed end of the impurity removal unit (6).

Images