CN109019642B - Method for extracting lithium carbonate from salt lake brine - Google Patents
Method for extracting lithium carbonate from salt lake brine Download PDFInfo
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- CN109019642B CN109019642B CN201811183552.5A CN201811183552A CN109019642B CN 109019642 B CN109019642 B CN 109019642B CN 201811183552 A CN201811183552 A CN 201811183552A CN 109019642 B CN109019642 B CN 109019642B
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01D—COMPOUNDS OF ALKALI METALS, i.e. LITHIUM, SODIUM, POTASSIUM, RUBIDIUM, CAESIUM, OR FRANCIUM
- C01D15/00—Lithium compounds
- C01D15/08—Carbonates; Bicarbonates
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2006/00—Physical properties of inorganic compounds
- C01P2006/80—Compositional purity
Abstract
The invention provides a method for extracting lithium carbonate from salt lake brine, which comprises the following steps: the temperature is kept constant through a gas inlet arranged at the lower end of the heating deviceContaining CO at a temperature below 500 DEG C2The gas is input into the heating device; inputting lithium-rich brine with pH of 7-9 into a heating device through a liquid inlet arranged at the upper end of the heating device, wherein the lithium-rich brine contains CO2The gas and the lithium-rich brine are convected in the heating equipment; CO22Entering into lithium-rich brine to form CO3 2‑And the lithium-rich brine absorbs the heat of the gas and is heated; lithium carbonate particles are precipitated from the lithium-rich brine after the temperature is raised, and a suspension containing the lithium carbonate particles is formed; discharging the suspension containing lithium carbonate particles into at least one filter unit, wherein the lithium carbonate particles are retained by a filter screen in the filter unit; and when the amount of the lithium carbonate particles intercepted by the filter screen reaches a preset threshold value, discharging the lithium carbonate concentrated salt slurry through the particle discharge port. The scheme provided by the invention can effectively improve the production efficiency of the lithium carbonate.
Description
Technical Field
The invention relates to the technical field of salt chemical engineering, in particular to a method for extracting lithium carbonate from salt lake brine.
Background
With the increasingly wide application of lithium metal and compounds thereof in aerospace, new materials, energy sources, chemical engineering, metallurgy, ceramics and other aspects, especially the rapid development of electric automobiles, the demand of lithium is increasing day by day. The extraction of lithium salts from salt lake brines has become the major production route for lithium salts.
Because the salt lake with more lithium resources in China is distributed in provinces such as Qinghai, Tibet, Xinjiang and the like in plateau areas with incomplete infrastructure, serious restriction is brought to the development and utilization of the lithium resources. At present, natural solarization, evaporative crystallization and chemical precipitation are mainly adopted for extracting lithium salts from salt lake water in the plateau regions, and lithium precipitation is carried out, but the sunshine solarization time consumption is usually 3-6 months, so that the production efficiency of the lithium salts is severely limited.
Disclosure of Invention
The embodiment of the invention provides a method for extracting lithium carbonate from salt lake brine, which can effectively improve the production efficiency of lithium carbonate, and meanwhile, lithium-rich brine flows from top to bottom and contains CO2The process of combustion gas rising from bottom to top, water produced after risingThe steam is condensed after meeting the lithium-rich brine, thereby greatly reducing the evaporation capacity of the brine and effectively avoiding the precipitation of sodium chloride due to supersaturation.
A method for extracting lithium carbonate from salt lake brine comprises the following steps:
the gas inlet arranged at the lower end of the heating device is used for containing CO at the temperature of not less than 500 DEG C2The combustion gas of (a) is fed into the heating device;
inputting lithium-rich brine with the pH value of 7-9 into the heating equipment through a liquid inlet arranged at the upper end of the heating equipment, wherein the lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine without magnesium ions and chloride type lithium-rich brine without magnesium ions;
said gas containing CO2Is convected with the lithium-rich brine in the heating apparatus;
the CO is2Into the brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas and is heated;
precipitating lithium carbonate particles from the lithium-rich brine after the temperature is raised to form a suspension containing the lithium carbonate particles;
discharging the suspension containing lithium carbonate particles into at least one filtering device, wherein the lithium carbonate particles are retained by a filter screen in the filtering device;
and when the amount of the lithium carbonate particles intercepted by the filter screen reaches a preset threshold value, discharging the lithium carbonate concentrated salt slurry through a particle discharge port.
Alternatively,
the gas inlet contains CO2The linear velocity of the combustion gas of (a) is not more than 1.5 m/s.
Alternatively,
in the water heating apparatus, the contained gas contains CO2The contact time of the combustion gas with the lithium-rich brine is not less than 2s and not more than 10 s.
Alternatively,
the temperature of the lithium-rich brine after being heated is not lower than (local boiling point-20 ℃) and not higher than the local boiling point.
Alternatively,
the above method further comprises:
heating each filtering device, wherein the temperature in each filtering device is not lower than the temperature of the lithium-rich brine after temperature rise and is not higher than the local boiling point.
Alternatively,
the longitudinal section of the filter device is of a conical structure, wherein a turbid liquid inlet is positioned on the side wall of the filter device at the lower part of the filter screen, a clear liquid outlet is positioned on the side wall of the filter device at the upper part of the filter screen, and a particle outlet is positioned at the bottom of the filter device;
discharging the suspension containing lithium carbonate particles into at least one filtration device comprising:
the suspension containing lithium carbonate particles enters the filtering device through the suspension inlet;
and the supernatant brine of the suspension passes through the filter screen and is discharged from the clear liquid discharge port.
Alternatively,
the above method further comprises:
spraying the supernatant brine discharged from the filtering device into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again;
and adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into the heating equipment.
Alternatively,
the above method further comprises:
respectively inputting the supernatant brine discharged by the filtering device and the external lithium-rich brine with the pH value of 7-9 into a heat exchange device, and exchanging heat between the supernatant brine and the lithium-rich brine with the pH value of 7-9 to reduce the temperature of the supernatant brine and preliminarily heat the lithium-rich brine with the pH value of 7-9;
spraying the supernatant brine with the reduced temperature into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again;
adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into the heat exchange device;
and inputting the lithium-rich brine with the pH value of 7-9 after the initial temperature rise into the heating equipment.
Alternatively,
the flow rate of the discharged lithium carbonate concentrated salt slurry is 5 kg/h-500 kg/h;
alternatively,
the solid density of the discharged lithium carbonate concentrated salt slurry is 1500kg/m3～3000kg/m3。
Alternatively,
the aperture of the filter screen is 3-5 mu m.
Alternatively,
the above method further comprises: setting a corresponding switch valve for each filtering device, wherein the filtering devices correspond to the switch valves one by one;
when the number of the filtering devices is at least two, constructing a linkage relation among the switch valves;
discharging the suspension containing lithium carbonate particles into at least one filtration device comprising: discharging the suspension containing the lithium carbonate particles into a filtering device corresponding to the switch valve in an open state;
when the amount of the lithium carbonate particles intercepted by the filter screen in the filtering device corresponding to the switch valve in the opening state reaches a preset threshold value, triggering the switch valve in the opening state to be in the closing state according to the linkage relation, and triggering the switch valve in the closing state to be in the opening state in a linkage way.
The embodiment of the invention provides a method for extracting lithium carbonate from salt lake brine, which comprises the steps of enabling the temperature to be not lower than 500 ℃ and CO to be contained through a gas inlet arranged at the lower end of heating equipment2The combustion gas is input into the heating device; inputting lithium-rich brine with pH of 7-9 into a liquid inlet arranged at the upper end of a heating deviceHeating equipment, wherein the lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine from which magnesium ions are removed and chloride type lithium-rich brine from which magnesium ions are removed; containing CO2The combustion gas and the lithium-rich brine are convected in the heating equipment; CO22Entering into lithium-rich brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas and is heated; lithium carbonate particles are precipitated from the lithium-rich brine after the temperature is raised, and a suspension containing the lithium carbonate particles is formed; discharging the suspension containing lithium carbonate particles into at least one filter unit, wherein the lithium carbonate particles are retained by a filter screen in the filter unit; when the amount of lithium carbonate particles retained by the filter screen reaches a preset threshold value, the lithium carbonate concentrated salt slurry is discharged through the particle discharge port, and compared with electric heating or solar heating, the lithium carbonate concentrated salt slurry is obtained by containing CO2The combustion gas and the lithium-rich brine convect in the heating equipment, so that the lithium-rich brine is heated, the heating time of the lithium-rich brine can be greatly shortened, the solubility of lithium carbonate is reduced due to the temperature rise of the brine, the heating time is shortened, lithium carbonate can be rapidly separated out, and therefore the production efficiency of lithium carbonate can be effectively improved.
In addition, the lithium-rich brine flows from top to bottom and contains CO2The process that rises from the bottom to the process of burning gas, the vapor that produces after the intensification meets lithium-rich brine, and the condensation makes lithium-rich brine evaporation capacity greatly reduced at the intensification in-process, and the reduction of the evaporation capacity of brine then can avoid sodium chloride to appear because of the supersaturation effectively to the purity of lithium carbonate has been improved effectively.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
Fig. 1 is a flow chart of a method for extracting lithium carbonate from salt lake brine according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a heating apparatus according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a filter apparatus according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of a heat exchange device according to an embodiment of the present invention;
fig. 5 is a schematic structural diagram of a system for extracting lithium carbonate from salt lake brine according to an embodiment of the present invention;
fig. 6 is a schematic structural diagram of a system for extracting lithium carbonate from salt lake brine according to another embodiment of the present invention;
fig. 7 is a schematic structural diagram of a system for extracting lithium carbonate from salt lake brine according to another embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer and more complete, the technical solutions in the embodiments of the present invention will be described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention, and based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative efforts belong to the scope of the present invention.
As shown in fig. 1, an embodiment of the present invention provides a method for extracting lithium carbonate from salt lake brine, which may include the following steps:
step 101: the gas inlet arranged at the lower end of the heating device is used for containing CO at the temperature of not less than 500 DEG C2The combustion gas of (a) is fed into the heating device;
step 102: inputting lithium-rich brine with the pH value of 7-9 into the heating equipment through a liquid inlet arranged at the upper end of the heating equipment, wherein the lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine without magnesium ions and chloride type lithium-rich brine without magnesium ions;
step 103: said gas containing CO2Is convected with the lithium-rich brine in the heating apparatus;
step 104: the CO is2Into the brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas and is heated;
step 105: precipitating lithium carbonate particles from the lithium-rich brine after the temperature is raised to form a suspension containing the lithium carbonate particles;
step 106: discharging the suspension containing lithium carbonate particles into at least one filtering device, wherein the lithium carbonate particles are retained by a filter screen in the filtering device;
step 107: and when the amount of the lithium carbonate particles intercepted by the filter screen reaches a preset threshold value, discharging the lithium carbonate concentrated salt slurry through a particle discharge port.
Wherein the temperature is not lower than 500 ℃ and contains CO2The combustion gas source can be generated by burning fuel oil such as gasoline, diesel oil, etc. in a hot blast stove, and the combustion gas generated in the hot blast stove contains CO2May be fed directly into the heating device to heat the water in the heating device.
The lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine for removing magnesium ions and chloride type lithium-rich brine for removing magnesium ions, wherein,
the carbonate type lithium-rich brine can be obtained by concentrating carbonate type salt lake water in an evaporation mode or other existing modes such as spray concentration and the like;
the sulfate type lithium-rich brine from which magnesium ions are removed can be removed by an evaporation mode or other existing modes, such as spray concentration and other sulfate type salt lake water, and magnesium ions can be removed by adding carbonate ions with the amount equivalent to that of the magnesium ions into the concentrated sulfate type salt lake water;
the chloride type lithium-rich brine from which magnesium ions are removed can be used for separating out sodium chloride by an evaporation mode or other existing modes such as spray concentration and other chloride type salt lake water, and removing the magnesium ions by adding carbonate ions with the amount equivalent to that of the magnesium ions into the concentrated chloride type salt lake water.
The structure of the heating apparatus may be as shown in fig. 2, and includes: a heating tank body 201, a gas inlet 202 arranged on the side wall of the lower end of the heating tank body, a liquid inlet 203 arranged on the side wall of the upper end of the heating tank body and a liquid outlet 204 arranged at the bottom of the heating tank body, wherein,
the temperature is not lower than 500 ℃ and contains CO2The combustion gas enters the heating tank body 201 through the gas inlet 202, and lithium-rich brine with the pH value of 7-9 enters the heating tank body 201 through the liquid inlet 203 and contains CO2The combustion gas upwards flows, the lithium-rich brine with the pH of 7-9 downwards flows, and CO is contained2The combustion gas and the lithium-rich brine are convected in the heating tank body 201, heat exchange occurs, and the lithium-rich brine absorbs and contains CO2Heat and CO of combustion gas2Increasing the temperature and forming CO3 2-(ii) a As the temperature of the lithium-rich brine increases, the solubility of lithium carbonate decreases, and lithium carbonate particles are precipitated from the lithium-rich brine after the temperature increases, thereby forming a suspension containing lithium carbonate particles, which is discharged to the filtration device through the liquid outlet 204. In the process, the water vapor formed by heating is condensed when meeting the lithium-rich brine. Thereby avoiding or greatly reducing the evaporation of water to avoid the precipitation of sodium chloride.
In addition, a liquid distributor is arranged in the heating tank body 201 to disperse the lithium-rich brine, so that the contact area between the lithium-rich brine and the combustion gas is increased.
In addition, the rich filler can be dispersed by providing a filler zone in the heating tank body 201, and filling the filler zone with a dispersing filler such as Raschig ring filler, pall ring filler, rectangular saddle filler, cascade ring, structured filler, metal Intel rock filler, theta net ring, ammonium net, or the likeLithium brine and lithium-containing lithium salt composition containing CO2To further increase the contact area of the lithium-rich brine with the combustion gas containing CO 2.
It is understood that there is no strict sequence between the steps 101 and 102, and the steps can be performed simultaneously, and in addition, when the heating device contains CO2After the combustion gas and the lithium-rich brine have formed a convection current, steps 101 to 107 can be performed simultaneously, except that in addition to steps 101 and 102, each of steps 103 to 107 is affected by the previous step or steps.
In the embodiment shown in FIG. 1, CO is contained at a temperature of not less than 500 ℃ through a gas inlet provided at the lower end of the heating apparatus2The combustion gas is input into the heating device; inputting lithium-rich brine with the pH value of 7-9 into heating equipment through a liquid inlet arranged at the upper end of the heating equipment, wherein the lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine from which magnesium ions are removed and chloride type lithium-rich brine from which magnesium ions are removed; CO 2-containing combustion gas is convected with the lithium-rich brine in the heating apparatus; CO22Entering into lithium-rich brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas and is heated; lithium carbonate particles are precipitated from the lithium-rich brine after the temperature is raised, and a suspension containing the lithium carbonate particles is formed; discharging the suspension containing lithium carbonate particles into at least one filter unit, wherein the lithium carbonate particles are retained by a filter screen in the filter unit; when the amount of lithium carbonate particles retained by the filter screen reaches a preset threshold value, the lithium carbonate concentrated salt slurry is discharged through the particle discharge port, and compared with electric heating or solar heating, the lithium carbonate concentrated salt slurry is obtained by containing CO2The combustion gas and the lithium-rich brine convect in the heating equipment, so that the lithium-rich brine is heated, the heating time of the lithium-rich brine can be greatly shortened, the solubility of lithium carbonate is reduced due to the temperature rise of the brine, the heating time is shortened, lithium carbonate can be rapidly separated out, and therefore the production efficiency of lithium carbonate can be effectively improved.
In addition, the lithium-rich brine flows from top to bottom and contains CO2From combustion gas ofIn the next ascending process, the water vapor generated after the temperature rise meets the lithium-rich brine, and is condensed, so that the evaporation capacity of the lithium-rich brine in the temperature rise process is greatly reduced, and the reduction of the evaporation capacity of the brine can effectively avoid the precipitation of sodium chloride due to supersaturation.
In addition, because the lithium-rich brine flows from top to bottom, the water vapor generated by heat absorption can meet the lithium-rich brine again and be condensed, so that the evaporation capacity of the lithium-rich brine is effectively reduced, the precipitation of sodium chloride is reduced and even avoided, and the purity of the precipitated lithium carbonate is effectively improved.
In order to ensure that the lithium-rich brine can be heated to a set temperature range and avoid carrying away the lithium-rich brine due to excessive combustion gas flow, in another embodiment of the present invention, the gas inlet comprises CO2The linear velocity of the combustion gas of (a) is not more than 1.5 m/s.
In order to ensure that the lithium-rich brine can be heated to a set temperature range, in another embodiment of the invention, in the hot water device, the water containing CO2The contact time of the combustion gas with the lithium-rich brine is not less than 2s and not more than 10 s. The contact time can be controlled by controlling the height of the hot water device, controlling the gas flow rate, controlling the flow rate of the lithium-rich brine, controlling the height of the packing area or the type of the packing in the packing area, etc., and the user can adjust the height of the lithium-rich brine and the type of the packing in the packing area according to the need, but the CO is ensured to be contained2Is not less than 2s and not more than 10s, and an excessively long contact time, the precipitated lithium carbonate particles may be deposited in the heating apparatus in the form of scale, and the CO-containing solution2The contact time of the combustion gas and the lithium-rich brine is not less than 2s and not more than 10s, so that the heating temperature can be ensured, and the deposition of lithium carbonate particles can be avoided.
In another embodiment of the invention, in order to ensure the precipitation amount of lithium carbonate, the temperature of the lithium-rich brine after being heated is not lower than (local boiling point-20 ℃) and not higher than the local boiling point. For example, the local boiling point is 80 ℃, and the temperature range of the heated lithium-rich brine can be 60-80 ℃.
In another embodiment of the present invention, in order to avoid re-dissolution of precipitated lithium carbonate particles caused by a decrease in temperature of the discharged suspension, the method further includes: heating each filtering device, wherein the temperature in each filtering device is not lower than the temperature of the lithium-rich brine after temperature rise and is not higher than the local boiling point. For example, the temperature of the heated lithium-rich brine is 70 ℃, and the temperature in each filtering device is not lower than 70 ℃.
In another embodiment of the present invention, the filter device has a tapered longitudinal section, and the tapered longitudinal section is a conical section
The suspension filter is characterized by comprising a filter device, a suspension inlet, a clear liquid outlet, a particle outlet and a particle outlet, wherein the suspension inlet is positioned on the side wall of the filter device at the lower part of the filter screen, the clear liquid outlet is positioned on the side wall of the filter device at the upper part of the filter screen, and the particle outlet is positioned at the bottom of the; discharging the suspension containing lithium carbonate particles into at least one filtration device comprising: the suspension containing lithium carbonate particles enters the filtering device through the suspension inlet; and the supernatant brine of the suspension passes through the filter screen and is discharged from the clear liquid discharge port. Turbid liquid gets into filter equipment from the turbid liquid entry of filter screen lower part promptly, and lithium carbonate granule is being held back by the filter screen, because action of gravity can be to sinking, and can not block up the filter screen to guarantee that the clear liquid discharge port that passes filter screen upper portion that supernatant brine can be more smooth and easy discharges, simultaneously, also make remaining on the filter screen of lithium carbonate granule as few as possible or in filter equipment, also further guaranteed the productivity of lithium carbonate salt. Meanwhile, the filtering device is selected for filtering, so that the filtering smoothness is guaranteed.
As shown in fig. 3, the filter device includes: the suspension filter comprises a filter body 301, a suspension inlet 302, a filter screen 303, a clear liquid outlet 304 and a particle outlet 305, wherein the suspension inlet 302 is positioned on the side wall of the filter body 301 at the lower part of the filter screen 303, the clear liquid outlet 304 is positioned on the side wall of the filter body 301 at the upper part of the filter screen 303, and the particle outlet 305 is positioned at the bottom of the filter body 301.
In order to completely extract lithium carbonate from the salt lake brine as much as possible, the lithium carbonate in the salt lake brine is extracted circularly, and the circular extraction can be realized by the following two ways.
The first way of realizing the cyclic extraction is as follows:
spraying the supernatant brine discharged from the filtering device into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again; and adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into heating equipment.
The process of inputting the reformed lithium-rich brine after the pH adjustment into the heating equipment may be inputting the reformed lithium-rich brine together with other lithium-rich brine, where the other lithium-rich brine may be lithium-rich brine directly obtained from salt lake water, or lithium-rich brine obtained through two or more cycles.
And a second mode for realizing cyclic extraction:
respectively inputting the supernatant brine discharged by the filtering device and the external lithium-rich brine with the pH value of 7-9 into a heat exchange device, and exchanging heat between the supernatant brine and the lithium-rich brine with the pH value of 7-9 to reduce the temperature of the supernatant brine and preliminarily heat the lithium-rich brine with the pH value of 7-9; generally, the temperature of the supernatant brine is reduced to about 40 ℃;
spraying the supernatant brine with the reduced temperature into a pool in a spraying manner, evaporating and cooling water, and precipitating sodium chloride crystals to form lithium-rich brine again;
adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into a heat exchange device;
and inputting the lithium-rich brine with the pH value of 7-9 after the initial temperature rise into heating equipment.
The process of inputting the reformed lithium-rich brine after the pH adjustment into the heat exchange device may be inputting the reformed lithium-rich brine together with other lithium-rich brine, where the other lithium-rich brine may be lithium-rich brine directly obtained from salt lake water, or lithium-rich brine obtained through two or more cycles.
Can make rich lithium brine have a preliminary preheating on the one hand through this heat transfer device promptly to improve the rate of rising temperature of rich lithium brine in firing equipment, on the other hand can make the preliminary cooling of supernatant brine, thereby improve the rate of falling temperature of supernatant brine, with the rate of appearing of improvement sodium chloride salt, improve the rate of forming rich lithium brine again simultaneously, thereby guarantee the production efficiency of lithium carbonate.
One structure of the heat exchange device can be as shown in fig. 4, the heat exchange device includes a housing 400 and two pipelines located in the guest, which are a first pipeline 401 and a second pipeline 402, respectively, the first pipeline 401 is a straight pipeline, the second pipeline 402 is wound on the first pipeline 401, wherein a water inlet 4011 of the first pipeline 401 and a water outlet 4022 of the second pipeline 402 are provided at a first end of the guest; the water outlet 4012 of the first pipeline 401 and the water inlet 4021 of the second pipeline 402 are arranged at the second end part of the object; a water inlet 4011 of the first pipeline 401 is communicated with a supernatant brine discharge port of the filter device, supernatant brine enters the first pipeline 401 through the water inlet 4011 of the first pipeline 401, lithium-rich brine (the lithium-rich brine can be directly obtained from salt lake water, or can be formed by mixing reformed lithium-rich brine with other lithium-rich brine, the other lithium-rich brine can be obtained directly from salt lake water, or can be obtained by circulating twice or more) enters the second pipeline 402 through a water inlet 4021 of the second pipeline 402, the supernatant brine and the lithium-rich brine run relatively, the supernatant brine is preliminarily cooled, the lithium-rich brine is preliminarily heated, and the preliminarily cooled supernatant brine is discharged from a water outlet 4012 of the first pipeline 401 to the spray device so as to be sprayed into a pool in a spray manner; the lithium-rich brine after the preliminary temperature rise is discharged from the water outlet 4022 of the second pipeline 402, and then enters the heating device through the liquid inlet of the heating device. The straight pipe is selected from the supernatant brine, so that the temperature of the supernatant brine can be prevented from being reduced too much, and the formation of spraying is ensured.
Understandably, the cooling rate of the supernatant brine can be improved by spraying the supernatant brine into a pool in a spraying mode, and in addition, because the temperature of the supernatant brine is higher (not lower than the local boiling point of-20 ℃), the supernatant brine has larger evaporation capacity by adopting the spraying mode, the evaporation of water can further promote the precipitation of sodium chloride crystals, and meanwhile, the supernatant brine becomes lithium-rich brine again, and the concentration of lithium in the lithium-rich brine is generally 800-1600 mg/L.
In another embodiment of the invention, in order to reduce the formation of scale in the lithium carbonate in the filter device as much as possible, the flow rate of the lithium carbonate concentrated salt slurry is discharged at 5kg/h to 500 kg/h.
In still another embodiment of the present invention, in order to ensure the use efficiency of the filtering device, the solid density of the discharged lithium carbonate concentrated salt slurry is 1500kg/m3～3000kg/m3。
That is, the above-mentioned preset threshold value may be that the solid density of the lithium carbonate concentrated salt slurry reaches 1500kg/m3～3000kg/m3。
In another embodiment of the present invention, the method further includes: setting a corresponding switch valve for each filtering device, wherein the filtering devices correspond to the switch valves one by one;
when the number of the filtering devices is at least two, constructing a linkage relation among the switch valves;
discharging the suspension containing lithium carbonate particles into at least one filtration device comprising: discharging the suspension containing the lithium carbonate particles into a filtering device corresponding to the switch valve in an open state;
when the amount of the lithium carbonate particles intercepted by the filter screen in the filtering device corresponding to the switch valve in the opening state reaches a preset threshold value, triggering the switch valve in the opening state to be in the closing state according to the linkage relation, and triggering the switch valve in the closing state to be in the opening state in a linkage way.
Wherein, the linkage relation means that any two switch valves are set to be opened/closed simultaneously or any two switch valves are set to be opened/closed asynchronously, such as: when two filtering devices are respectively a filtering device A and a filtering device B, and a switch valve corresponding to the filtering device A is set to be opened, a switch valve corresponding to the filtering device B is correspondingly closed, for example, when four filtering devices are respectively a filtering device C, a filtering device D, a filtering device E and a filtering device F, a switch valve corresponding to the filtering device C can be set to be opened, a switch valve corresponding to the filtering device D is synchronously opened, a switch valve corresponding to the filtering device E and a switch valve corresponding to the filtering device F are correspondingly closed, correspondingly, when a switch valve corresponding to the filtering device C is closed, a switch valve corresponding to the filtering device D is synchronously closed, a switch valve corresponding to the filtering device E and a switch valve corresponding to the filtering device F are correspondingly opened, so that the alternative use of the filtering devices is realized, and the continuous filtering is ensured.
In another embodiment of the present invention, the aperture of the filter screen is 3 to 5 μm.
The lithium carbonate concentrated salt slurry discharged from each of the above examples may be dried by evaporation, airing, natural air drying, or the like to obtain a lithium carbonate solid.
To further illustrate the method of extracting lithium carbonate from salt lake brine, several specific examples are described below.
Example 1:
the system provided by the figure 5 is used for extracting lithium carbonate from plateau salt lake brine with the altitude of 4600m, and the specific implementation process is as follows: the gas inlet 5011 arranged at the lower end of the heating device 501 is used for introducing CO into the heating device at a linear velocity of 1.5m/s and at a temperature of not lower than 500 deg.C2The combustion gas of (a) is input into the heating device 501; the carbonate type lithium-rich brine with the pH of 7-9 is fed into the heating equipment 501 through a liquid inlet 5012 arranged at the upper end of the heating equipment 501 at a mass flow rate of 500kg/h, wherein the carbonate type lithium-rich brine contains CO2The input of the combustion gas and the input of the carbonate type lithium-rich brine are synchronously carried out;
containing CO2The convective contact time of the combustion gas and the lithium-rich brine in the heating device 501 is 2s, and the time of the convective contact of the combustion gas and the lithium-rich brine is CO2Into brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gasHeating to 60 ℃, and precipitating lithium carbonate particles from the heated lithium-rich brine to form a suspension containing the lithium carbonate particles;
discharging the suspension containing lithium carbonate particles into the filtering device 502 through the liquid outlet 5014 at the bottom of the heating apparatus, the connecting line, and the suspension inlet 5021 of the filtering device 502, wherein the lithium carbonate particles are retained by the filter screen 5022 with the pore size of 3 μm in the filtering device; the supernatant brine of the suspension passes through the filter screen and is discharged from the clear liquid discharge port 5023 of the filter 502, and when the amount of lithium carbonate particles retained by the filter screen 5022 reaches a preset threshold value (the solid density of the lithium carbonate concentrated salt slurry is 1500 kg/m)3) At the time, the opening/closing valve 5024 corresponding to the filter device 502 closes the suspension inlet 5021, stops the input of the suspension into the filter device 502, discharges the concentrated lithium carbonate salt slurry through the particle discharge port 5024 of the filter device 502 at a flow rate of 5kg/h, and opens the opening/closing valve 5034 corresponding to the filter device 503 according to the linkage relationship to input the suspension into the filter device 503 through the suspension inlet 5031 for filtration, i.e., lithium carbonate particles are retained by the filter net 5032 with a pore size of 4 μm in the filter device 503; the supernatant brine of the suspension passes through the filter 5032 and is discharged from the clear liquid outlet 5033 of the filter 503, and when the amount of lithium carbonate particles retained by the filter 5032 reaches a predetermined threshold (the solid density of the lithium carbonate concentrated salt slurry is 1800 kg/m)3) During the operation, the suspension inlet 5031 is closed through the on-off valve 5034 corresponding to the filter device 503, the suspension input into the filter device 503 is stopped, the lithium carbonate concentrated salt slurry is discharged through the particle discharge port 5034 of the filter device 503 at a flow rate of 50kg/h, and simultaneously, the on-off valve 5024 corresponding to the filter device 502 is opened according to the linkage relationship, so that the linkage use of the filter device is realized, and the continuous and uninterrupted filtration is ensured;
spraying the discharged supernatant brine into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again; and adjusting the pH value of the reformed lithium-rich brine to 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into heating equipment. And drying the discharged lithium carbonate concentrated salt slurry to obtain a lithium carbonate solid. In this example, 5kg of lithium carbonate solid can be obtained from each ton of lithium-rich brine, the recovery rate of lithium carbonate per pass reaches 40%, and the purity of lithium carbonate reaches 95% or more.
Example 2:
the system shown in fig. 6 is used for extracting lithium carbonate from salt lake brine with the altitude of 4600m, and the specific implementation process is as follows: the gas inlet 6011 arranged at the lower end of the heating apparatus 601 is used to introduce CO into the mixture at a temperature of not less than 500 deg.C and a linear velocity of 1.0m/s2The combustion gas of (a) is input into the heating device 501; feeding the sulfate type lithium-rich brine with pH of 7-9 and without magnesium ions into the heating equipment 601 at a mass flow rate of 500kg/h through a liquid inlet 6012 arranged at the upper end of the heating equipment 601, wherein the lithium-rich brine contains CO2The input of the combustion gas and the input of the sulfate type lithium-rich brine from which the magnesium ions are removed are synchronously carried out;
said gas containing CO2The convection contact time of the combustion gas and the lithium-rich sulfate brine without magnesium ions in the heating equipment 601 is 4s, and the CO is2Into the brine to form CO3 2-Absorbing the heat of the combustion gas by the lithium-rich brine, heating to 70 ℃, and separating lithium carbonate particles from the heated lithium-rich brine to form a suspension containing lithium carbonate particles;
discharging the suspension containing the lithium carbonate particles into the filtering device 602 and the filtering device 604 through a liquid outlet 6014 at the bottom of the heating apparatus, the connecting pipeline, a suspension inlet 6021 of the filtering device 602 and a suspension inlet 6041 of the filtering device 604, wherein the lithium carbonate particles entering the filtering device 602 are retained by a filter screen 6022 with a pore size of 5 μm, and the lithium carbonate particles entering the filtering device 604 are retained by a filter screen 6042 with a pore size of 4 μm; the supernatant brine of the suspension passes through the filter screen and is discharged from the clear liquid discharge port 6023 of the filter unit 602 and the clear liquid discharge port 6043 of the filter unit 604 respectively, when the amount of lithium carbonate particles retained by the filter screen 6022 reaches a preset threshold (i.e. the solid density of the lithium carbonate concentrated salt slurry is 3000 kg/m)3) Or when the amount of the lithium carbonate particles retained by the filter screen 6042 reaches a preset threshold value (namely the solid density of the lithium carbonate concentrated salt slurry is 2000 kg/m)3) In this case, only the filter device 602 and the filter device 6 need to be used04, when any one of the amounts of lithium carbonate particles retained by the filter screen reaches a preset threshold value, the suspension inlet 6021 is closed by the on-off valve 6024 corresponding to the filter device 602, the supply of the suspension to the filter device 602 is stopped, the lithium carbonate concentrated salt slurry was discharged through the particle discharge port 6024 of the filter unit 602 at a flow rate of 100kg/h, and in an interlocking relationship, the suspension inlet 6041 is closed by the open/close valve 6044 corresponding to the filter 604, the suspension is stopped from being supplied to the filter 604, the lithium carbonate concentrated salt slurry was discharged through the particle discharge port 6044 of the filter 604 at a flow rate of 500kg/h, meanwhile, according to the linkage relationship, the switch valve 6034 corresponding to the filtering device 603 is opened to input the suspension into the filtering device 603 through the suspension inlet 6031 for filtering, and the lithium carbonate particles are intercepted by the filter screen 6032 with the aperture of 3 μm in the filtering device 603 in the filtering process; the supernatant brine of the suspension passes through the filter screen 6032 and is discharged from a clear liquid discharge port 6033 of the filter device 603, and when the amount of lithium carbonate particles retained by the filter screen 6032 reaches a preset threshold value (the solid density of the lithium carbonate concentrated salt slurry is 1500 kg/m)3) When in use, the switch valve 6034 corresponding to the filter device 603 closes the suspension inlet 6031, stops inputting the suspension into the filter device 603, discharges the lithium carbonate concentrated salt slurry at the flow rate of 200kg/h through the particle discharge port 6034 of the filter device 603, and simultaneously opens the switch valve 6024 corresponding to the filter device 602 and the switch valve 6024 corresponding to the filter device 602 according to the linkage relationship, namely, the linkage use of the filter device is realized, and the continuous and uninterrupted filtration is ensured;
spraying the discharged supernatant brine into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again; and adjusting the pH value of the reformed lithium-rich brine to 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into heating equipment. And drying the discharged lithium carbonate concentrated salt slurry to obtain a lithium carbonate solid. In this example, 6kg of lithium carbonate solid can be obtained per ton of lithium-rich brine, the recovery rate of lithium carbonate per pass reaches 45%, and the purity of lithium carbonate reaches 95% or more.
Example 3
Obtaining chlorination for removing magnesium ions through plateau salt lake brine with altitude of 4600mThe physical lithium-rich brine is prepared by extracting lithium carbonate from chloride lithium-rich brine from which magnesium ions are removed by using the system shown in fig. 7, and the specific implementation process comprises the following steps: the gas inlet 7011 arranged at the lower end of the heating device 701 is used for introducing CO into the gas at a linear velocity of 0.8m/s and at a temperature of not lower than 500 deg.C2The combustion gas of (a) is input into the heating apparatus 701; the chloride type lithium-rich brine with pH of 7-9 and without magnesium ions is fed into the heating equipment 701 through a liquid inlet 7012 arranged at the upper end of the heating equipment 701 at a mass flow rate of 50kg/h, wherein the chloride type lithium-rich brine contains CO2The input of the combustion gas and the input of the chloride type lithium-rich brine for removing magnesium ions are synchronously carried out;
containing CO2The convection contact time of the combustion gas and the chloride type lithium-rich brine for removing magnesium ions in the heating equipment 501 is 6s, and CO is2Into brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas, the temperature is raised to 80 ℃, lithium carbonate particles are separated out from the lithium-rich brine after the temperature is raised, and suspension containing the lithium carbonate particles is formed;
discharging the suspension containing lithium carbonate particles into the filtering device 702 through a liquid outlet 7014 at the bottom of the heating device, a connecting pipeline and a suspension inlet 7021 of the filtering device 702, wherein the lithium carbonate particles are retained by a filter screen 7022 with a pore size of 3 μm in the filtering device; the supernatant brine of the suspension passes through the filter screen and is discharged from a clear liquid discharge port 7023 of the filter unit 702, and when the amount of lithium carbonate particles retained by the filter screen 7022 reaches a preset threshold value (the solid density of the lithium carbonate concentrated salt slurry is 1500 kg/m)3) When the lithium carbonate slurry is filtered, the switch valve 7024 corresponding to the filtering device 702 is used for closing the suspension inlet 7021, stopping inputting the suspension into the filtering device 702, discharging the lithium carbonate concentrated salt slurry through the particle discharge port 7024 of the filtering device 702 at the flow rate of 10kg/h, and simultaneously, the switch valve 7034 corresponding to the filtering device 703 is opened according to the linkage relation, so that the suspension is input into the filtering device 703 through the suspension inlet 7031 for filtering, wherein the lithium carbonate particles are intercepted by the filter screen 7032 with the aperture of 4 μm in the filtering device 703 in the filtering process; supernatant brine of the suspension passes through a filter screen 7032 and is discharged from a supernatant discharge port 7033 of the filter device 703, and when lithium carbonate particles are trapped by the filter screen 7032The amount of granules reaches a preset threshold value (the solid density of the lithium carbonate concentrated salt slurry is 1800 kg/m)3) When the lithium carbonate concentrated salt slurry is used, the suspension inlet 7031 is closed through the switch valve 7034 corresponding to the filtering device 703, the suspension is stopped being input into the filtering device 703, the lithium carbonate concentrated salt slurry is discharged through the particle discharge port 7034 of the filtering device 703 at the flow rate of 50kg/h, and meanwhile, the switch valve 7024 corresponding to the filtering device 702 is opened according to the linkage relation, so that the linkage use of the filtering device is realized, and the continuous and uninterrupted filtering is ensured;
supernatant brine discharged by the filtering device 702/703 enters the first pipeline 7041 through a water inlet of the first pipeline 7041 of the heat exchange device 704, lithium-rich brine (the lithium-rich brine can be directly obtained from salt lake water, or can be formed again to be mixed with other lithium-rich brine, the other lithium-rich brine can be directly obtained from salt lake water, or can be obtained through twice or more than twice circulation) enters the second pipeline 7042 through a water inlet of the second pipeline 7042 of the heat exchange device 704, the supernatant brine and the lithium-rich brine relatively run, the supernatant is preliminarily cooled, the lithium-rich brine is preliminarily heated, and the supernatant brine after preliminary cooling is discharged from a water outlet of the first pipeline 7041 to the spraying device 705 so as to be sprayed into a pool in a spraying manner; the lithium-rich brine after the initial temperature rise is discharged from the water outlet of the second pipeline 7042, and enters the heating device through the liquid inlet of the heating device.
After the supernatant brine is discharged from a water outlet of the first pipeline to a spraying device, spraying the supernatant brine into a pool in a spraying mode, evaporating and cooling water, separating out sodium chloride crystals, and reforming lithium-rich brine; and adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into a second pipeline of the heat exchange device as the lithium-rich brine. And drying the discharged lithium carbonate concentrated salt slurry to obtain a lithium carbonate solid. In this example, 7kg of lithium carbonate solid can be obtained per ton of lithium-rich brine, the recovery rate of lithium carbonate per pass reaches 50%, and the purity of lithium carbonate reaches 95% or more.
Example 4
Through an altitude of 4600mObtaining carbonate type lithium-rich brine from plateau salt lake brine, and extracting lithium carbonate from the carbonate type lithium-rich brine by using the system shown in figure 5, wherein the lithium carbonate contains CO2The linear velocity of the combustion gas is 0.6m/s, the mass flow of the chloride type lithium-rich brine is 25kg/h, the convection contact time in the heating equipment is 10s, and the temperature is raised to 80 ℃. And discharging the lithium carbonate concentrated salt slurry at the flow rate of 50kg/h by using the filtering device, and drying the discharged lithium carbonate concentrated salt slurry to obtain a lithium carbonate solid. In this example, 7.4kg of lithium carbonate solid can be obtained per ton of lithium-rich brine, the recovery rate of single-pass lithium carbonate reaches 52%, and the purity of lithium carbonate reaches 97% or more.
It should be noted that, in the above embodiments, when the heating device discharges the suspension to the filtering device, the flow rate of the suspension is controlled by the drainage pump.
The above embodiments can achieve at least the following advantages:
1. the gas inlet arranged at the lower end of the heating device is used for containing CO at the temperature of not less than 500 DEG C2The combustion gas is input into the heating device; inputting lithium-rich brine with the pH value of 7-9 into heating equipment through a liquid inlet arranged at the upper end of the heating equipment, wherein the lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine from which magnesium ions are removed and chloride type lithium-rich brine from which magnesium ions are removed; containing CO2The combustion gas and the lithium-rich brine are convected in the heating equipment; CO22Entering into lithium-rich brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas and is heated; lithium carbonate particles are precipitated from the lithium-rich brine after the temperature is raised, and a suspension containing the lithium carbonate particles is formed; discharging the suspension containing lithium carbonate particles into at least one filter unit, wherein the lithium carbonate particles are retained by a filter screen in the filter unit; when the amount of lithium carbonate particles retained by the filter screen reaches a preset threshold value, the lithium carbonate concentrated salt slurry is discharged through the particle discharge port, and compared with electric heating or solar heating, the lithium carbonate concentrated salt slurry is obtained by containing CO2The combustion gas and the lithium-rich brine are convected in the heating equipment, so that the temperature of the lithium-rich brine is raised, and the temperature rise of the lithium-rich brine can be greatly shortenedThe lithium carbonate solution is low in solubility and short in temperature rise time along with the rise of the temperature of the brine, so that the lithium carbonate can be rapidly separated out, and the production efficiency of the lithium carbonate salt can be effectively improved.
2. The lithium-rich brine flows from top to bottom and contains CO2The process that rises from the bottom of burning gas, the steam that produces after the intensification meets behind the rich lithium brine, the condensation, because rich lithium brine flows from the top down promptly, can meet rich lithium brine again and condense because of the steam that the heat absorption produced, make the evaporation capacity greatly reduced of rich lithium brine in the intensification process, and the reduction of the evaporation capacity of brine, then can avoid sodium chloride to appear because of the supersaturation effectively to the purity of the lithium carbonate of appearing has been improved effectively.
3. In the embodiment of the invention, the CO is contained by controlling2The combustion gas and the contact time of lithium-rich brine are not less than 2s and not more than 10s, so that the heating temperature can be ensured, and the deposition of lithium carbonate particles can be avoided, thereby avoiding the deposition of the lithium carbonate particles in the heating equipment to form scale.
4. In the embodiment of the invention, each filtering device is heated, wherein the temperature in each filtering device is not lower than the temperature of the lithium-rich brine after being heated and is not higher than the local boiling point, so that the re-dissolution of the precipitated lithium carbonate particles can be effectively avoided.
5. In the embodiment of the invention, the selected filtering device can enable the suspension to enter the filtering device from the suspension inlet at the lower part of the filter screen, and lithium carbonate particles can sink due to the action of gravity after being intercepted by the filter screen, so that the filter screen cannot be blocked, and the supernatant brine can smoothly pass through the filter screen and be discharged from the clear liquid outlet at the upper part of the filter screen.
6. In the embodiment of the invention, the discharged supernatant brine is sprayed into a pool in a spraying mode, water is evaporated and cooled, sodium chloride crystals are separated out, and lithium-rich brine is formed again; and adjusting the pH value of the reformed lithium-rich brine to 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into the heating equipment, so that lithium carbonate in the salt lake brine can be completely extracted as far as possible.
7. In the embodiment of the invention, the supernatant brine discharged from a filtering device and the external lithium-rich brine with the pH value of 7-9 are respectively input into a heat exchange device, heat exchange is carried out between the supernatant brine and the lithium-rich brine with the pH value of 7-9, the temperature of the supernatant brine is reduced, and the temperature of the lithium-rich brine with the pH value of 7-9 is preliminarily increased; generally, the temperature of the supernatant brine is reduced to about 40 ℃; spraying the supernatant brine with the reduced temperature into a pool in a spraying manner, evaporating and cooling water, and precipitating sodium chloride crystals to form lithium-rich brine again; adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into a heat exchange device; and inputting the lithium-rich brine with the pH value of 7-9 after the initial temperature rise into heating equipment. Can make rich lithium brine have a preliminary preheating on the one hand through this heat transfer device promptly to improve the rate of rising temperature of rich lithium brine in firing equipment, on the other hand can make the preliminary cooling of supernatant brine, thereby improve the rate of falling temperature of supernatant brine, with the rate of appearing of improvement sodium chloride salt, improve the rate of forming rich lithium brine again simultaneously, thereby guarantee the production efficiency of lithium carbonate. Meanwhile, the energy can be saved to the maximum extent by preliminarily preheating the lithium-rich brine and preliminarily cooling the supernatant brine, and the energy consumption is further reduced.
8. In the embodiment of the invention, the lithium-rich brine can be rapidly heated through the heating equipment, and the precipitated lithium carbonate is filtered through the filtering device.
9. In the embodiment of the invention, the discharged supernatant brine is sprayed into a pool in a spraying manner, water is evaporated and cooled, sodium chloride crystals are separated out, and simultaneously the extraction of sodium chloride is realized.
10. In the embodiment of the invention, because the combustion gas is in convective contact with the lithium-rich brine in the heating equipment, the contact time is generally 2-10 s, the driving force of heat transfer between the combustion gas and the lithium-rich brine is relatively large, meanwhile, the lithium-rich brine can re-condense water vapor, the evaporation of the lithium-rich brine is avoided, and the energy consumption in the whole temperature rise and lithium carbonate particle precipitation process is relatively low.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a" does not exclude the presence of other similar elements in a process, method, article, or apparatus that comprises the element.
Finally, it is to be noted that: the above description is only a preferred embodiment of the present invention, and is only used to illustrate the technical solutions of the present invention, and not to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.
Claims (8)
1. A method for extracting lithium carbonate from salt lake brine is characterized by comprising the following steps:
the gas inlet arranged at the lower end of the heating device is used for containing CO at the temperature of not less than 500 DEG C2The combustion gas of (a) is fed into the heating device;
inputting lithium-rich brine with the pH value of 7-9 into the heating equipment through a liquid inlet arranged at the upper end of the heating equipment, wherein the lithium-rich brine is any one of carbonate type lithium-rich brine, sulfate type lithium-rich brine without magnesium ions and chloride type lithium-rich brine without magnesium ions;
said gas containing CO2Is convected with the lithium-rich brine in the heating apparatus;
the CO is2Into the brine to form CO3 2-And the lithium-rich brine absorbs the heat of the combustion gas and is heated;
precipitating lithium carbonate particles from the lithium-rich brine after the temperature is raised to form a suspension containing the lithium carbonate particles;
discharging the suspension containing lithium carbonate particles into at least one filtering device, wherein the lithium carbonate particles are retained by a filter screen in the filtering device;
when the amount of the lithium carbonate particles intercepted by the filter screen reaches a preset threshold value, discharging lithium carbonate concentrated salt slurry through a particle discharge port;
said gas inlet containing CO2The linear velocity of the combustion gas of (a) is not more than 1.5 m/h;
in the heating apparatus, the gas containing CO2The contact time of the combustion gas with the lithium-rich brine is not less than 2s and not more than 10 s.
2. The method of claim 1, further comprising:
heating each filtering device, wherein the temperature in each filtering device is not lower than the temperature of the lithium-rich brine after temperature rise and is not higher than the local boiling point.
3. The method of claim 1,
the longitudinal section of the filter device is of a conical structure, wherein a turbid liquid inlet is positioned on the side wall of the filter device at the lower part of the filter screen, a clear liquid outlet is positioned on the side wall of the filter device at the upper part of the filter screen, and a particle outlet is positioned at the bottom of the filter device;
discharging the suspension containing lithium carbonate particles into at least one filtration device comprising:
the suspension containing lithium carbonate particles enters the filtering device through the suspension inlet;
and the supernatant brine of the suspension passes through the filter screen and is discharged from the clear liquid discharge port.
4. The method according to any one of claims 1 to 3,
the temperature of the lithium-rich brine after being heated is not lower than the local boiling point of-20 ℃ and not higher than the local boiling point.
5. The method of any of claims 1 to 3, further comprising:
spraying the supernatant brine discharged by the filtering device into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again;
and adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into the heating equipment.
6. The method of any of claims 1 to 3, further comprising:
respectively inputting the supernatant brine discharged by the filtering device and the external lithium-rich brine with the pH value of 7-9 into a heat exchange device, and exchanging heat between the supernatant brine and the lithium-rich brine with the pH value of 7-9 to reduce the temperature of the supernatant brine and preliminarily heat the lithium-rich brine with the pH value of 7-9;
spraying the supernatant brine with the reduced temperature into a pool in a spraying manner, evaporating and cooling water, and separating out sodium chloride crystals to form lithium-rich brine again;
adjusting the pH value of the reformed lithium-rich brine to be 7-9, and inputting the reformed lithium-rich brine after the pH value is adjusted into the heat exchange device;
and inputting the lithium-rich brine with the pH value of 7-9 after the initial temperature rise into the heating equipment.
7. The method according to claim 1 or 3,
the flow rate of the discharged lithium carbonate concentrated salt slurry is 5 kg/h-500 kg/h;
and/or the presence of a gas in the gas,
the solid density of the discharged lithium carbonate concentrated salt slurry is 1500kg/m3～3000kg/m3；
And/or the presence of a gas in the gas,
the aperture of the filter screen is 3-5 μm.
8. The method according to any one of claims 1 to 3,
further comprising: setting a corresponding switch valve for each filtering device, wherein the filtering devices correspond to the switch valves one by one;
when the number of the filtering devices is at least two, constructing a linkage relation among the switch valves;
discharging the suspension containing lithium carbonate particles into at least one filtration device comprising: discharging the suspension containing the lithium carbonate particles into a filtering device corresponding to the switch valve in an open state;
when the amount of the lithium carbonate particles intercepted by the filter screen in the filtering device corresponding to the switch valve in the opening state reaches a preset threshold value, triggering the switch valve in the opening state to be in the closing state according to the linkage relation, and triggering the switch valve in the closing state to be in the opening state in a linkage way.
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| CN102275956A (en) * | 2011-07-21 | 2011-12-14 | 清华大学 | Method for extracting lithium carbonate from salt lake brine with high magnesium/lithium ratio |
| CN102976367A (en) * | 2012-12-20 | 2013-03-20 | 青海锂业有限公司 | Method for preparing battery-level lithium carbonate by using salt lake brine |
| CN103787374A (en) * | 2012-10-31 | 2014-05-14 | 西藏国能矿业发展有限公司 | Method for extracting lithium carbonate from salt lake bittern |
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| CN107640779A (en) * | 2017-11-15 | 2018-01-30 | 天元锂电材料河北有限公司 | Spodumene produces lithium carbonate technique |
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| US9028789B2 (en) * | 2012-05-14 | 2015-05-12 | Pedro Manuel Brito da Silva Correia | Process to produce lithium carbonate directly from the aluminosilicate mineral |
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| CN102275956A (en) * | 2011-07-21 | 2011-12-14 | 清华大学 | Method for extracting lithium carbonate from salt lake brine with high magnesium/lithium ratio |
| CN103787374A (en) * | 2012-10-31 | 2014-05-14 | 西藏国能矿业发展有限公司 | Method for extracting lithium carbonate from salt lake bittern |
| CN102976367A (en) * | 2012-12-20 | 2013-03-20 | 青海锂业有限公司 | Method for preparing battery-level lithium carbonate by using salt lake brine |
| CN104386715A (en) * | 2014-10-17 | 2015-03-04 | 金川集团股份有限公司 | Method for preparing low-magnetism high-purity lithium carbonate by using saline lithium salt |
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