Method for extracting lithium carbonate from carbonate brine

Technical Field

The invention relates to a method for extracting of inorganic salts, more precisely, relates to a kind of from carbonate type bittern method of extracting lithium carbonate.

Background Art

High performance lithium material with the development and application of the, lithium of the world's increasing demand. In recent years, has been gradually replace the salt lake bittern the hard crag lithium ore raises the lithium process, a method for the production of the lithium salt. My lithium resources are abundant, and mainly distributed in the salt lake in a plateau region, wherein tibet saltlake bittern lithium resources mainly carbonate type, for extracting from bittern, using lithium study is a very meaningful work.

Chinese Patent 99105828.3 (from carbonate type bittern method for extracting lithium salt) discloses a from carbonate type bittern method of extracting lithium salt. The method utilizes kogen cold natural advantages, a large amount of Glauber's salt to precipitate, from saltlake extracting high-lithium low sulfate brine as raw materials, the multi-stage freezing sun and around the-control-mechanism-mother liquor pool, the stone salt, Glauber's salt precipitate in a large amount of the sun around the separation, lithium in the brine and reach the pre-concentration, then concentrated to the control cell, the lithium content in the brine up to 1.5-2.8 grams per litro, and the temperature in the 5 above [...] , control pours the halogen to crystalline pool, the pool is enriched in the high-grade, thickness daichi gao Lihun salt , grade lithium carbonate containing the same in 5% or more.

Chinese Patent 02129355.4 (from carbonate-type bittern by means a method of crystallization precipitated lithium carbonate) provides a pool as crystallization of the solar pond from carbonate type bittern method of separation by crystallization in lithium carbonate. Clay is enclosed directly in the solar pond, plastic film and hydromagnesite is at the bottom of the tank a sandwich structure, the inner wall of a tank body with black geotechnological film or high-density polyethylene, polyvinyl chloride as a gasket, the thermal storage process of the solar pond with the lithium carbonate precipitation of the integration of the process, the available grade of 60% of the mixed salt is lithium carbonate, this kind of method of low cost, simple structure of the tank bodies, full utilization of solar energy, high economic returns.

Chinese Patent 200620172864.2 (for extracting lithium from brine solar cell device) provides a solar pond for extracting lithium from brine device. A tank body comprises a main body structure layer, the layer along the sidewalls and the bottom of the tank upward are sequentially distributed with a water-proof moisture-proof layer, insulating layer, corrosion-resistant and water-proof heat sink. Device is composed of four layers or five-layer structure, the most upper layer is corrosion-resistant and water-proof heat sink, absorbing effectively the selected good anti-corrosion material and special insulation structure, the heat insulation of the solar pond heat storage effect is better, by 20-40 absorbing solar heat storage after day, winter temperature can reach at the bottom of the tank the 30-50 [...] , summer and fall seasons can reach the temperature at the bottom of the tank the 50-80 [...] , thereby accelerating crystallization from carbonate type brine precipitated lithium carbonate, improving the crystallization rate, improving the production efficiency, continuous operation can be realized.

On the basis of the above-mentioned method, the invention further exploration from carbonate type bittern extracting high efficiency and low cost in the technical means of high-grade lithium carbonate.

In a plateau region under high altitude conditions, lithium salts in the carbonate type bittern is not easy to be concentrated is separated out, and the sun is the evaporation of the brine precipitated dispersed in the process, this extremely detrimental to the extraction of high-grade lithium carbonate. Research shows that, the solubility of the lithium carbonate with negative temperature effect, that is, the solubility of the lithium carbonate in the water is reduced with the rise of the temperature the, and carbonate type brines in the majority of the other salts with positive temperature effect, that is, its solubility is increased with the rise of the temperature of the. Therefore, when the brine in the lithium content of the reach or approach the saturation point, temperature will become the control indicators precipitated lithium carbonate, the temperature can be utilized the principle of heating brine from carbonate type bittern sinks the lithium extracting high-grade lithium carbonate.

The artificial heating method or carbonization method, while can concentrate on precipitated lithium carbonate, but need to consume a large number of fossil fuel, the energy shortage tibet plateau region is not feasible. Radiation heating by solar energy, while a single form of the solar pond brine crystalline analyzes the lithium , while heating the brine and substantially no evaporation, but the brine is relatively slow rate of rise of temperature, resulting in longer production period, in the solar pond to harvesting fills the halogen from lithium mixed salt take up to more than two months time. And, the current taken against the thermal insulation measures not only the cost is high, but also is not able to meet the process requirements, in particular poor heat accumulating capacity of the pool body, so that the brine of the large temperature difference between day and night, during the day under the irradiation of strong of the sun, brine can be lifted to the highest temperature of the 40 [...] , however, the temperature of brine at night will be lowered significantly, cause rock salt, borax, and the crystallization of salts separated from the low-temperature brine, from the high-temperature brine of which have been precipitated in the part of the lithium carbonate will also re-meltaback to the salt brine, seriously affected the grade of lithium carbonate. Furthermore, adopting the above-mentioned patented method (99105828.3, 02129355.4, 200620172864.2) the lithium mixes the salt the outputs, because of the high-quality, long-distance transportation is required only to the mainland can be purified, in this way each year will consume a large number of freight and energy.

Content of the invention

This invention, in order to solve the problems existing in the prior art, from the center to provide a method of extracting lithium carbonate brine, fully consider saltlake of the geographical and resource advantages, the salt gradient thermal insulation of the solar pond-geothermal water heat exchange-temperature fresh water scrubbing polytechniques, in from carbonate type brine and pollution-free high-efficiency and low-cost to extract high-grade lithium carbonate.

Technical solution of this invention is:

In order to is provided with a heat exchange of the pipeline insulation solar pond as perabrodil gradient method, crystallization of from carbonate type brine precipitated lithium carbonate, the working medium of the sun is prepared by freezing brine lithiated. The salt gradient thermal insulation of the solar pond is built directly from the clay, lighting area 1000-10000m², pool deep 3-4m, bottom of the pool and the inner wall of a tank body are made of plastic and a heat insulation material to form the heat insulation layer of the sandwich structure, black surface can be provided with in the pool-propylene water-proof material, or high density polyethylene geomembrane as gasket sprayplastic canvas and the like. High at the bottom of the tank at a distance of 0.5-1m is provided with a U-shaped or spiral heat exchange pipeline. The heat transfer efficiency of the heat exchanging pipe of high corrosion-resistant material, such as stainless steel, or PE-RT PP-R and other materials, the high temperature geothermal hot water can flow through, the particular U-shaped or spiral structure enhances the heat transfer efficiency of the heat exchange pipe.

Prepared by freezing the sun directly into the pool of the lithiated the brine, the brine surface laying a layer of fresh water, is formed between the spring and the tube blank supporting salt gradient layer of a certain thickness, play the role of preventing heat loss upwards, mechanism is as follows: 1, the structure comprises a layer of the solar pond by the plastic film and insulation material to form a thermal insulation layer, the better the insulating effect of the solar pond; 2, compared with the ordinary solar cell, the solar pond of this Patent is not completely dependent on the radiation effect of the sun, but to rely mainly on high temperature circulating heat exchange of the hot water in the continued supply of heat, the solar pond of this Patent therefore changes of air temperature and season by day and night the impact of the replacement is relatively small, so the heating and insulating effect is better.

The different refractive index of the fresh water and brine, the stored heat of the absorbed solar energy in the brine at the bottom of the tank, forming stored energy area , so as to raise and maintain the temperature of the lower layer of brine. At the same time, by the heat exchange pipe to the inlet of the hot water of high temperature is introduced, the geothermal hot water in the process of flowing through the whole pipeline to carry out heat exchange with the brine outside the pipe, outside the tube to the temperature of the brine in a short time and can be rapidly raised greatly reduced temperature, and the geothermal water after cooling by the heat exchange flows out of the outlet of the pipeline and is recharged into the underground. The solar radiation and geothermal water heat exchange of the double role, bittern on the center of the pipeline is provided with a heat exchange salt gradient thermal insulation solar pool heating rate is not only clearly accelerated, the temperature range is also increased, greatly shortens the production period, in other words from the salt gradient thermal insulation solar the pond fills the halogen to harvesting lithium mixed salt only 10 days of time, and obtain lithium mixed salt in high grade is of lithium carbonate (temperature control is a key factor in grade precipitated lithium carbonate. Find through the experiment, the temperature of the tube blank supporting 50 the above [...] the high grade is the precipitation of the lithium carbonate. ), And the product yield of production efficiency can be also remarkably improved.

Shallow pool of opening up to the temperature of fresh water as a heat storage tank. The clay is built directly from the shallow pool, area 1000-10000m², pool deep 1-2m, bottom of the pool and the inner wall of a tank body are made of plastic and a heat insulation material to form the heat insulation layer of the sandwich structure. Filling in the pool and maintain a certain amount of fresh water, fresh water under irradiation of the sun which is heated absorbs the solar heat, the temperature of the fresh water will be elevated temperature (the temperature of the 20 more than [...]) scrubbing the above-mentioned by salt gradient thermal insulation solar pool of high-grade the lithium mixes the salt harvesting, other salts to remove the impurity, thereby further increasing the lithium mixed salt grade of lithium carbonate (because the solubility of the lithium carbonate with negative temperature effect, and the most of the solubility of the other salts with positive temperature effect, therefore, the higher the temperature of fresh water for scrubbing lithium mixed salt, lithium carbonate is not easy to be dissolved, and other salts by washing away it will be easier, to improve the grade lithium carbonate. ), Finally obtain the lithium carbonate concentrate.

The advantage of this invention is to:

Full use of the plateau region abundant solar energy resources and carbonate type saltlake vicinity of geothermal energy and other new energy, is provided with a heat exchange pipe in the salt gradient thermal insulation solar pond as a mechanism of lithium carbonate, the solar radiation and geothermal water heat exchange temperature under the dual effect of the brine, so that it is easy to disperse in the evaporation process in a large amount of the concentrated precipitate lithium carbonate, improving the production efficiency and product yield, shorten the production period, to realize uninterrupted throughout the year producing lithium carbonate.

Salt gradient thermal insulation solar pond adopts a plastic film and insulation material to form the heat insulation layer of the sandwich structure, the inner surface of the pool with black-propylene water-proof material, or high density polyethylene geomembrane as gasket sprayplastic canvas and the like. High at the bottom of the tank and at a distance of 0.5-1m is provided with a heat exchange pipe is, the high-temperature circulation flow in the pipe to the hot water can be continuously supplying heat to the brine, the changes of air temperature and season by day and night the impact of the replacement is relatively small, and the brine amplitude and the temperature rise rate of rise of temperature can be greatly enhanced; geothermal water after cooling can be recycled or be recharged into the underground, without any environmental pollution and loss of resources, and can greatly reduce the production cost, and reducing the consumption of fossil fuels;

Natural heating fresh water by using solar energy, in order to open as a shallow pool of water heat, the thermal insulation shallow pool similarly adopts the plastic film and insulation material to form a sandwich structure, saves construction cost; the temperature of the fresh water will be elevated temperature scrubbing lithium mixed salt, a good effect of washing, the product quality is high, lithium carbonate concentrate can be obtained.

The method fully utilizes the abundant solar energy resources in high altitude area, geothermal resources and saltlake resources, , the salt gradient thermal insulation solar pond, the geothermal water heat exchange and sensors is combined with fresh water scrubbing method, applied to extracting lithium carbonate carbonate type bittern, greatly improves the production efficiency and product quality, shorten the production cycle, the production cost is reduced, can be used in local to directly obtain lithium carbonate concentrate.

Description of drawings

Figure 1 shows a method of extracting lithium carbonate of this invention flow schematic diagram of the process.

Mode of execution

Combining the Figure below Mode of execution of this invention further description.

With reference to Figure 1, this invention discloses a method for extracting lithium carbonate, is provided with a heat exchange pipe in the salt gradient thermal insulation solar pond as crystallization pool from carbonate type brines separation by crystallization in lithium carbonate. Said salt gradient thermal insulation of the solar pond is built directly from the clay, lighting area 1000-10000m², pool deep 3-4m, bottom of the pool and the inner wall of a tank body are made of plastic and a heat insulation material to form the heat insulation layer of the sandwich structure, black surface can be provided with in the pool-propylene water-proof material, or high density polyethylene geomembrane as gasket sprayplastic canvas and the like, in order to prevent the brine infiltration; high at the bottom of the tank at a distance of 0.5-1m is provided with a U-shaped or spiral heat exchange pipeline. The heat transfer efficiency of the heat exchanging pipe of high corrosion-resistant material, such as stainless steel, or PE-RT PP-R and other materials, the high temperature geothermal hot water can flow through, the particular U-shaped or spiral structure enhances the heat transfer efficiency of the heat exchange pipe.

To carbonate-type lithium-containing brine is used as a raw material, the lithium enriched Chineses brine obtained after freezing the sun (Li+ concentration 1.5-2.8 grams per litro), directly into the salt gradient in the thermal insulation of the solar pond to a depth of about 1.5-2.5m; laying the brine surface a layer of fresh water of about 0.3-0.5m, (here -0.3 0.5m to the depth of the tube blank supporting 1.5-2.5m more suitable spring depth. If the spring is more than 0.5m, not only will the lower part of the dilution of the brine, the lithium concentration is reduced, and the forming of the total thickness of the transition layer of the spring and will also increase, thereby preventing the lower tube blank supporting the absorption of the solar heat, the temperature effect is not remarkable in brine. ) At this time in salt gradient thermal insulation of the solar pond and the tube blank supporting spring of the total depth of about 1.8-3.0 meter Formed between the spring and the tube blank supporting salt gradient layer of a certain thickness, play the role of preventing heat loss upwards, mechanism is as follows: 1, the structure comprises a layer of the solar pond by the plastic film and insulation material to form a thermal insulation layer, the better the insulating effect of the solar pond; 2, compared with the ordinary solar cell, the solar pond of this Patent is not completely dependent on the radiation effect of the sun, but to rely mainly on high temperature circulating heat exchange of the hot water in the continued supply of heat, the solar pond of this Patent therefore changes of air temperature and season by day and night the impact of the replacement is relatively small, so the heating and insulating effect is better.

The different refractive index of the fresh water and brine, the stored heat of the absorbed solar energy in the brine at the bottom of the tank, forming stored energy area , so as to raise and maintain the temperature of the lower layer of brine. At the same time, by the heat exchange pipe to the inlet of the hot water of high temperature is introduced, the geothermal hot water in the process of flowing through the whole pipeline to carry out heat exchange with the brine outside the pipe, outside the tube to the temperature of the brine in a short time and can be rapidly raised greatly reduced temperature, and the geothermal water after cooling by the heat exchange flows out of the outlet of the pipeline and is recharged into the underground. The solar radiation and geothermal water heat exchange of the double role, bittern on the center of the pipeline is provided with a heat exchange salt gradient thermal insulation solar pool heating rate is not only clearly accelerated, the temperature range is also increased, greatly shortens the production period.

The inlet of the heat exchanger comprises a heat exchange pipe to inject the high-temperature hot water (the temperature of the 60 [...] the above, according to the solubility of the lithium carbonate is reduced by the temperature rise of the law, the higher the temperature of geothermal water, the more the separation quantity of lithium carbonate, the higher the yield of the product. ), The geothermal hot water flowing through the pipeline in the process of low temperature brine to carry out heat exchange with the fluid, at the same time, low temperature brine by salt gradient thermal insulation of the solar pond and storage of solar energy for the heating of the geothermal water for the double role, in the short term (approximately 10 days the time of the right and left) can be warmed up rapidly, and the highest temperature can be up to 60 the above [...] , at the same time also lithium carbonate precipitated heavily concentrated in the pool, the lithium mixed salt up to grade lithium carbonate 75-85%.

At the same time, in order to open as a shallow pool of water heat fresh water temperature rise. The clay is built directly from the shallow pool, area 1000-10000m², pool deep 1-2m, bottom of the pool and the inner wall of a tank body are made of plastic and a heat insulation material to form the heat insulation layer of the sandwich structure. Filling in the pool and maintain a certain amount of fresh water, fresh water under irradiation of the sun which is heated absorbs the solar heat, the temperature of the fresh water will be elevated temperature (the temperature of the 20 more than [...]) scrubbing the above-mentioned by salt gradient thermal insulation solar pool of high-grade the lithium mixes the salt harvesting, other salts to remove the impurity, thereby further increasing the lithium mixed salt grade of lithium carbonate (because the solubility of the lithium carbonate with negative temperature effect, and the most of the solubility of the other salts with positive temperature effect, therefore, the higher the temperature of fresh water for scrubbing lithium mixed salt, lithium carbonate is not easy to be dissolved, and other salts by washing away it will be easier, to improve the grade lithium carbonate. ), The grade can be obtained finally 90% more lithium carbonate concentrate.

The method of the present invention, full use of the plateau region abundant solar energy resources and carbonate type saltlake vicinity of geothermal energy and other new energy, is provided with a heat exchange pipe in the salt gradient thermal insulation solar pond as a mechanism of lithium carbonate, the solar radiation and geothermal water heat exchange temperature under the dual effect of the brine, so that it is easy to disperse in the evaporation process in a large amount of the concentrated precipitate lithium carbonate, improving the production efficiency and product yield, shorten the production period, to realize uninterrupted throughout the year producing lithium carbonate.

Salt gradient thermal insulation solar pond adopts a plastic film and insulation material to form the heat insulation layer of the sandwich structure, the inner surface of the pool with black-propylene water-proof material, or high density polyethylene geomembrane as gasket sprayplastic canvas and the like. High at the bottom of the tank and at a distance of 0.5-1m is provided with a heat exchange pipe is, the high-temperature circulation flow in the pipe to the hot water can be continuously supplying heat to the brine, the changes of air temperature and season by day and night the impact of the replacement is relatively small, and the brine amplitude and the temperature rise rate of rise of temperature can be greatly enhanced; geothermal water after cooling can be recycled or be recharged into the underground, without any environmental pollution and loss of resources, and can greatly reduce the production cost, and reducing the consumption of fossil fuels;

Natural heating fresh water by using solar energy, in order to open as a shallow pool of water heat, the thermal insulation shallow pool similarly adopts the plastic film and insulation material to form a sandwich structure, saves construction cost; the temperature of the fresh water will be elevated temperature scrubbing lithium mixed salt, a good effect of washing, the product quality is high, lithium carbonate concentrate can be obtained.

The method fully utilizes the abundant solar energy resources in high altitude area, geothermal resources and saltlake resources, , the salt gradient thermal insulation solar pond, the geothermal water heat exchange and sensors is combined with fresh water scrubbing method, applied to extracting lithium carbonate carbonate type bittern, greatly improves the production efficiency and product quality, shorten the production cycle, the production cost is reduced, can be used in local to directly obtain lithium carbonate concentrate.