CN-224220779-U - Energy-saving device for freezing and crystallizing lithium carbonate

CN224220779UCN 224220779 UCN224220779 UCN 224220779UCN-224220779-U

Abstract

The utility model discloses an energy-saving device for freezing and crystallizing lithium carbonate, and relates to a device for recycling cold energy by LNG gasification and a heat exchange device for freezing and crystallizing lithium carbonate. The LNG gasification recycling cold energy device uses propane as an intermediate heat exchange medium to exchange heat with LNG and glycol solution, and the glycol solution after heat exchange cools materials in a lithium carbonate freezing crystallization process. According to the utility model, the refrigerant for recycling the cold energy is adopted, the cryogenic cold energy of LNG can be absorbed by utilizing the lower freezing point temperature of the refrigerant, and the partial cold energy is utilized in the lithium carbonate freezing crystallization process, so that not only can the steam used during LNG vaporization be avoided, but also the refrigerant can be combined with the lithium carbonate freezing crystallization process, so that the cold energy is fully and reasonably utilized, the energy consumption is reduced, the environment is more friendly, the energy consumption and the carbon emission of the whole production process are reduced, and the utilization of liquefied natural gas in factories and the lithium carbonate freezing crystallization process form good energy utilization and recycling, and the production cost is reduced.

Inventors

LI JING
WANG HONGWEI
HUANG YUHUA
CHEN CHONGSHAN
CHEN YIHENG
MENG QING
FU XIAOJUN

Assignees

湖南紫金锂多金属新材料有限公司

Dates

Publication Date: 20260512
Application Date: 20250428

Claims (8)

1. The energy-saving device for freezing and crystallizing lithium carbonate is characterized by comprising an IFV heat exchanger (1), an ethylene glycol mixing tank (2), a refrigerating unit (3), a freezing and crystallizing heat exchanger (4), a condenser (5) and an ethylene glycol storage tank (6) which are sequentially connected through pipelines, a refrigerating pump and an ethylene glycol storage tank (6) which are respectively arranged among the ethylene glycol mixing tank (2) and the refrigerating unit (3), and a conveying pump (7) arranged among the IFV heat exchanger (1), wherein a heat exchange medium is filled in the IFV heat exchanger (1), an LNG pipeline is communicated with the IFV heat exchanger (1), an ethylene glycol solution circulates in the IFV heat exchanger (1), the ethylene glycol mixing tank (2), the refrigerating unit (3), the freezing and crystallizing heat exchanger (4), the condenser (5) and the ethylene glycol storage tank (6), freezing and crystallizing materials are subjected to cooling treatment through the freezing and LNG is gasified through the IFV heat exchanger (1).
2. The energy-saving device for freezing and crystallizing lithium carbonate according to claim 1, wherein the IFV heat exchanger (1) is provided with a double-layer heat exchange tube and a heat exchange tank (11), the double-layer heat exchange tube comprises an upper heat exchange tube (12) and a lower heat exchange tube (13), the upper heat exchange tube (12) is arranged at the upper part of the heat exchange tank (11), the lower heat exchange tube (13) is arranged at the lower part of the heat exchange tank (11), an inlet and an outlet of the upper heat exchange tube (12) are communicated with an inlet and outlet pipeline of LNG, and an inlet of the lower heat exchange tube (13) is communicated with a conveying pump (7) and an outlet of the lower heat exchange tube is communicated with the ethylene glycol mixing tank (2).
3. The energy-saving device for freezing and crystallizing lithium carbonate according to claim 1, wherein the boiling point of the heat exchange medium is-52 ℃ to-40 ℃, and the ethylene glycol solution is 50-60% by mass.
4. An energy saving device for the freeze crystallization of lithium carbonate according to claim 1, wherein the heat exchange medium is propane, R507 refrigerant or R410 refrigerant.
5. The energy-saving device for freezing and crystallizing lithium carbonate according to claim 1, wherein a glycol reflux pipe (8) is arranged between the freezing and crystallizing heat exchanger (4) and the glycol mixing tank (2).
6. The energy-saving device for freezing and crystallizing lithium carbonate according to claim 2, wherein the temperature of LNG entering the IFV heat exchanger (1) is-162 ℃ to-160 ℃, the temperature of an outlet of the lower heat exchange tube (13) is-22 ℃ to-18 ℃, and the temperature of the ethylene glycol mixing tank (2) is-10 ℃ to-8 ℃.
7. The energy-saving device for freezing and crystallizing lithium carbonate according to claim 1, wherein the freezing unit (3) starts or stops running according to the quantity of frozen crystallization materials or the quantity of cold required, so as to realize accurate control of crystallization temperature.
8. The energy-saving device for freezing and crystallizing lithium carbonate according to claim 1, wherein the temperature of the glycol solution in the glycol storage tank (6) is 2-5 ℃.

Description

Energy-saving device for freezing and crystallizing lithium carbonate Technical Field The application belongs to the technical field of recovery, and particularly relates to an energy-saving device for freezing and crystallizing lithium carbonate. Background With the rapid development of power batteries and energy storage devices in the new energy field, the demand of lithium carbonate as an important raw material is increasing, wherein the extraction of lithium from lithium ores is an important way for industrially obtaining lithium carbonate. In the process of extracting lithium by using lepidolite ore, the lithium precipitation mother liquor is firstly subjected to acid regulation and decarbonization, and then is conveyed into an evaporation crystallizer by a raw material pump to be evaporated and crystallized, and part of sodium sulfate decahydrate is dissolved. The material evaporated by the evaporation crystallizer enters a centrifugal machine for centrifugal separation, the separated crystals are subjected to a drying process, and the separated mother solution returns to the evaporation crystallizer for continuous evaporation crystallization. And (3) after lithium is concentrated by evaporation and crystallization, the concentrated lithium enters a flash crystallizer for flash crystallization, the material subjected to flash crystallization enters a centrifugal machine for centrifugal separation, the separated crystal is leached by leaching liquid and enters a drying process, and the separated mother solution enters a freezing crystallizer for freezing crystallization. The frozen and crystallized materials are subjected to primary flash evaporation and secondary flash evaporation, the temperature of the materials is reduced from 90 ℃ to 35 ℃, the materials are frozen to-5 ℃ for crystallization through a refrigerating unit, and the crystallized mirabilite is subjected to hot melting and then is sent to sodium sulfate evaporation crystallization equipment, and the byproduct anhydrous sodium sulfate is obtained after drying. And (5) freezing and crystallizing potassium and sodium mixed salt, drying and returning to a roasting workshop for recycling. As can be seen from the temperature required by the process, the required refrigeration energy is larger and the energy consumption is higher. In industrial application, a refrigerating machine is generally adopted to exchange heat for a refrigerant, the refrigerant exchanges heat for a crystallization material, so that the frozen crystallization material reaches the crystallization temperature of the material, crystallization and growth of crystals are finished, and the crystals are sent to sodium sulfate evaporation crystallization equipment after hot melting, and are dried to obtain a byproduct anhydrous sodium sulfate. In the traditional freezing crystallization process, the temperature of a primary flash material is reduced from 90 ℃ to 45 ℃, the vapor obtained by flash evaporation is cooled by circulating water to obtain condensed water, the temperature of a secondary flash material is reduced from 45 ℃ to 35 ℃, and the vapor obtained by flash evaporation exchanges heat with a refrigerant discharged from a refrigerator and is cooled to obtain the condensed water. The frozen crystallization material is subjected to heat exchange and cooling by a refrigerant discharged from a refrigerator, the temperature is reduced from 35 ℃ to-5 ℃, mirabilite is crystallized, and the product sodium sulfate is delivered to sodium sulfate evaporation crystallization equipment after hot melting, and is dried to obtain a byproduct anhydrous sodium sulfate. The production process needs more cold energy consumption, has large carbon emission and large refrigerating fluid circulation. Therefore, how to reduce the energy consumption of the freezing crystallization is of great significance to the lithium carbonate freezing crystallization process. Disclosure of utility model In view of the above problems, the present application provides an energy-saving device for freezing and crystallizing lithium carbonate, which can solve the problems of large energy consumption and low production efficiency caused by close freezing in the lithium carbonate production process. According to the energy-saving device for freezing and crystallizing lithium carbonate, which is provided by the application, the energy-saving device comprises an IFV heat exchanger, an ethylene glycol mixing tank, a refrigerating unit, a freezing and crystallizing heat exchanger, a condenser, an ethylene glycol storage tank, a refrigerating pump arranged between the ethylene glycol mixing tank and the refrigerating unit, a conveying pump arranged between the ethylene glycol storage tank and the IFV heat exchanger, wherein a heat exchange medium is filled in the IFV heat exchanger, an LNG pipeline is communicated with the IFV heat exchanger, an ethylene glycol solution circulates in the IFV heat exchanger, the ethyle