Method and system for preparing high-purity lithium carbonate

Abstract

The invention discloses a method and system for preparing high-purity lithium carbonate. The method for preparing the high-purity lithium carbonate includes the following steps that carbonic acid type salt lake brine is concentrated and then warmed, lithium carbonate is saturated and crystallized out, and crystals are collected to obtain lithium carbonate refined salt; distilled water recovered when brine with the temperature of 60 DEG C or above is evaporated and concentrated is utilized to flush the collected lithium carbonate refined salt, and then sodium sylvite in the refined salt is dissolved; drying is conducted to obtain the high-purity lithium carbonate. According to the process, a chemical reagent is not needed, the lithium carbonate can be purified only through physical operation, the purity of the purified lithium carbonate reaches 95% or above, and therefore transportation cost in later periods and cost of further purification are beneficially reduced. The process is low in requirements for transportation and can not pollute the environment.

Description

technical field

[0001] The invention relates to a process and system for purifying lithium carbonate. Background technique

[0002] Due to its strong electrochemical activity and being a light metal, lithium has a wide range of uses. At present, the application fields of lithium include: ceramics and glass, synthetic rubber, aluminum production, plastics, pharmaceuticals, lubricants, air conditioners, televisions (fluorescent screens), lithium batteries, lithium alloys and nuclear industry, etc.; consumption reaches tens of thousands of tons per year , and still growing.

[0003] In the world's total lithium resources, brine lithium ore accounts for about 75%, and hard rock lithium ore accounts for 25%. In my country's total lithium resources, brine lithium ore accounts for about 72%, and hard rock lithium ore accounts for 28%. Before the 1960s, lithium resources mainly came from hard salt lithium ore. The cost of extracting lithium from salt lakes is 1-1.5 times lower th...

Examples

preparation example Construction

[0040] The preparation method of high-purity lithium carbonate comprises the steps:

[0041] 1) Concentrate the carbonated salt lake brine, then raise the temperature to precipitate lithium carbonate saturated crystals, collect the crystals to obtain lithium carbonate refined salt;

[0042] 2) Rinse the collected lithium carbonate fine salt with the distilled water recovered when the brine is evaporated and concentrated above 60°C, and dissolve the sodium potassium salt therein;

[0043] 3) drying to obtain high-purity lithium carbonate.

[0044] Preferably, the salt lake brine is concentrated by evaporation under reduced pressure, and then the temperature is raised to above 60°C, preferably above 65°C or 70°C to precipitate lithium carbonate crystals. The higher the crystallization temperature, the more conducive to the precipitation of higher-purity lithium carbonate refined salt, which is conducive to reducing the difficulty of subsequent purification operations.

[0045]...

Embodiment 1

[0059] Li ion concentration 1.29g / L brine, above 60°C crystallization precipitates coarse lithium salt and brine mixed wet salt, simply removes the supernatant and weighs 897.6g, mixes with 80°C distilled water 3000g at one time and fully stirs for 3 minutes, after Suction filtration and oven dry, obtain the lithium carbonate 47.4g that purity is 62%, obtain lithium carbonate yield from thick lithium salt and be 73.5%.

[0060]

Embodiment 2

[0062] Li ion concentration 1.29g / L brine, above 60°C crystallizes and precipitates coarse lithium salt and brine mixed wet salt, simply removes the supernatant and weighs 877.9g, uses 70°C distilled water 2250g, respectively 1200g, 600g, 300g, 150g A total of 4 times were rinsed in the manner of Example 1, and each fully stirred for 30 seconds for a total of 2 minutes. After suction filtration and drying, the dry purity obtained was 91.3% Lithium Retard 37.56g, and Lithium Retard yield was obtained from the thick lithium salt. was 85.7%.

[0063]

technical field

[0001] The invention relates to a process and system for purifying lithium carbonate. Background technique

[0002] Due to its strong electrochemical activity and being a light metal, lithium has a wide range of uses. At present, the application fields of lithium include: ceramics and glass, synthetic rubber, aluminum production, plastics, pharmaceuticals, lubricants, air conditioners, televisions (fluorescent screens), lithium batteries, lithium alloys and nuclear industry, etc.; consumption reaches tens of thousands of tons per year , and still growing.

[0003] In the world's total lithium resources, brine lithium ore accounts for about 75%, and hard rock lithium ore accounts for 25%. In my country's total lithium resources, brine lithium ore accounts for about 72%, and hard rock lithium ore accounts for 28%. Before the 1960s, lithium resources mainly came from hard salt lithium ore. The cost of extracting lithium from salt lakes is 1-1.5 times lower th...

Examples

preparation example Construction

[0040] The preparation method of high-purity lithium carbonate comprises the steps:

[0041] 1) Concentrate the carbonated salt lake brine, then raise the temperature to precipitate lithium carbonate saturated crystals, collect the crystals to obtain lithium carbonate refined salt;

[0042] 2) Rinse the collected lithium carbonate fine salt with the distilled water recovered when the brine is evaporated and concentrated above 60°C, and dissolve the sodium potassium salt therein;

[0043] 3) drying to obtain high-purity lithium carbonate.

[0044] Preferably, the salt lake brine is concentrated by evaporation under reduced pressure, and then the temperature is raised to above 60°C, preferably above 65°C or 70°C to precipitate lithium carbonate crystals. The higher the crystallization temperature, the more conducive to the precipitation of higher-purity lithium carbonate refined salt, which is conducive to reducing the difficulty of subsequent purification operations.

[0045]...

Embodiment 1

[0059] Li ion concentration 1.29g / L brine, above 60°C crystallization precipitates coarse lithium salt and brine mixed wet salt, simply removes the supernatant and weighs 897.6g, mixes with 80°C distilled water 3000g at one time and fully stirs for 3 minutes, after Suction filtration and oven dry, obtain the lithium carbonate 47.4g that purity is 62%, obtain lithium carbonate yield from thick lithium salt and be 73.5%.

[0060]

Embodiment 2

[0062] Li ion concentration 1.29g / L brine, above 60°C crystallizes and precipitates coarse lithium salt and brine mixed wet salt, simply removes the supernatant and weighs 877.9g, uses 70°C distilled water 2250g, respectively 1200g, 600g, 300g, 150g A total of 4 times were rinsed in the manner of Example 1, and each fully stirred for 30 seconds for a total of 2 minutes. After suction filtration and drying, the dry purity obtained was 91.3% Lithium Retard 37.56g, and Lithium Retard yield was obtained from the thick lithium salt. was 85.7%.

[0063]

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