System and method for leaching alkaline-earth metal ions

Abstract

The present invention relates to the technical field of comprehensive utilization of solid waste, and in particular to a system and method for leaching alkaline-earth metal ions. The system comprises a leaching reactor, the leaching reactor comprising a tower body, a leaching cylinder and a downcomer, wherein an ammonia gas exhaust outlet is provided at the top of the tower body, and a slag discharge outlet is provided at the bottom of the tower body; the leaching cylinder is fixedly arranged inside the tower body by means of a support member, and a heat exchange coil is fixedly arranged inside the leaching cylinder; and the downcomer is fixedly arranged at the top of the interior of the tower body and is sleeved outside the leaching cylinder; and a clear-liquid outlet is provided at the upper part of the tower body, a solid-liquid feeding pipe is provided at the lower part of the tower body, and the tail end of the solid-liquid feeding pipe extends into the leaching cylinder. The present invention uses the concept of reaction-separation coupling, and uses an ammonium chloride solution as a leaching agent; and the reaction time of alkaline-earth metals and a leaching solution is prolonged by means of a circulating flow, and an ammonia gas produced during the reaction can also be exhausted in a timely manner, thereby promoting the progress of the reaction and increasing the leaching rate of calcium out of calcium-containing silicates.

Description

A system and method for leaching alkaline earth metal ions This application claims priority to the Chinese patent application filed with the Patent Office of China on December 26, 2023, with application number 202311808339.X and invention name “A system and method for leaching alkaline earth metal ions”, the entire contents of which are incorporated by reference into this application. Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of solid waste, and in particular to a system and method for leaching alkaline earth metal ions. Background Art

[0002] Utilizing calcium and magnesium-containing raw materials from nature and industrial solid waste to react with industrially emitted CO2 to produce calcium carbonate and magnesium carbonate can not only achieve the capture and utilization of CO2 and the comprehensive utilization of calcium and magnesium resources, but also replace the existing industrial process of decomposing limestone to prepare precipitated calcium carbonate, thereby reducing carbon emissions from limestone mining and processes.

[0003] Currently, a viable technical approach for producing precipitated carbonates using alkaline earth metals containing calcium and magnesium from natural and industrial solid waste as raw materials and reacting them with industrially emitted CO₂ is to first extract the calcium and magnesium from the raw materials into a solution, then pass industrially emitted CO₂ through the extracted solution for a gas-liquid absorption reaction to produce precipitated calcium carbonate. Numerous prior art documents and patents report on different technical solutions for extracting calcium and magnesium components from raw materials and their mineralization reactions with CO₂. These solutions can be broadly categorized into the following three types:

[0004] First, use acid to dissolve and extract calcium and magnesium components, and use alkali to assist the reaction of CO2 with calcium and magnesium. For example, patent CN101134155A and literature Ding W, Fu L, Ouyang J, et al. (2014) CO2 mineral sequestration by wollastonite carbonation. Physics and Chemistry of Minerals 41(7): 489-496 reported using inorganic acids (HCl, H2SO4, HNO3) and organic acids (HCOOH, CH3COOH) as auxiliary agents to leaching serpentine and mineralize CO2 under alkaline conditions.

[0005] Second, salt decomposition is used to produce acid and base, with the acid solution extracting calcium and magnesium components. A base is then used to assist the reaction of CO2 with calcium and magnesium. The resulting salt is then pyrolyzed and recycled. For example, patent CN104284707A reports the pyrolysis of hydrated magnesium chloride to produce hydrochloric acid and basic magnesium chloride / magnesium hydroxide. Hydrochloric acid is used to extract the calcium and magnesium components from the silicate, and basic magnesium chloride / magnesium hydroxide is used to adjust the alkalinity of the solution, allowing the CO2 to react with carbonate. Another example is the research team of Gretta Larisa Aurora Arce Ferrufino at the Brazilian Space Research Institute, which used serpentine as a raw material, hydrochloric acid as a leaching agent, and ammonia as a precipitant to mineralize CO2. The resulting mineralized mother liquor is an aqueous solution of NH4Cl. The mother liquor is evaporated, concentrated, and crystallized at high temperature, followed by thermal decomposition to recover HCl and NH3. The main problems with this route are that salts typically require pyrolysis or electrolysis to produce acids and bases, which consumes a lot of energy, the pyrolysis temperature is usually high, and the equipment has high requirements for corrosion resistance and other performance. Furthermore, the large amount of solid / molten salt involved is involved, making the process complex and difficult to engineer.

[0006] Third, calcium and magnesium components are extracted and dissolved using a recyclable solvent or solution, and the solvent or solution can be regenerated when reacting with CO2. This type of circulating solvent is mainly a weak acid solution or a solution of a strong acid and weak base salt with an acidity higher than silicic acid but lower than carbonic acid. For example, patent CN101134155A proposes to leach calcium-containing silicate with acetic acid to obtain a calcium acetate solution, which is further mineralized in a CO2 atmosphere to generate calcium carbonate and acetic acid. The acetic acid is extracted by adding an organic solvent such as tributyl phosphate (TBP) to promote the forward direction of the mineralization reaction, and the acetic acid is recycled after stripping; for example, patents CN106745146A and CN105197975A report a route using ammonium chloride solution as a circulating solution to extract calcium contained in calcium silicate in steel slag. The process flow of this route is relatively simple, and the use of a circulating solvent or solution solves the problem of acid and alkali consumption, which has great industrial practical value.

[0007] However, there are few reports on proprietary equipment for steel slag leaching. In industry, reactors with stirring devices are generally used to leach steel slag. However, this method has a low steel slag leaching rate and a long leaching time. At the same time, there is a leaching passivation problem when treating steel slag with ammonium chloride solution.

[0008] In order to solve the above problems, patent CN105197975A discloses a method for preparing light calcium carbonate using converter steel slag, which uses microwave irradiation as an auxiliary means in the leaching process. Although this method greatly shortens the leaching time by using the microwave field, the temperature of the reaction system rises significantly during the reaction process, and the solution boils after a period of reaction, which easily leads to changes in the reaction system. In addition, the energy consumption during the reaction is large, the steel slag composition is complex, the physical phase is variable, and the degree of crushing difficulty varies, which brings uncertainty to the treatment of the steel slag. Patent CN115779844A discloses a slag reactor, which mainly extends the action time of the steel slag and the leaching solution by setting a horizontal cylinder, spikes and baffles, and avoids the formation of an inert layer on the surface of the particles during the leaching process. Although this method improves the element leaching efficiency, the concentration of ammonia generated during the reaction gradually increases, which seriously inhibits the smooth progress of the leaching reaction to a certain extent.

[0009] In view of this, the present invention is proposed. Summary of the Invention

[0010] The object of the present invention is to provide a system and method for leaching alkaline earth metal ions. The system not only prolongs the reaction time between the alkaline earth metal and the leaching solution by circulating, but also can promptly remove ammonia generated by the reaction, thereby promoting the reaction and improving the leaching rate of calcium in calcium silicate.

[0011] In a first aspect, the present invention provides a leaching reactor comprising:

[0012] The tower body has an ammonia discharge port at the top, a slag discharge port at the bottom, a clear liquid outlet at the top, and a feed port at the bottom.

[0013] The leaching cylinder is arranged in the tower body, and the leaching reactor can be divided into a leaching area and a sedimentation area through the leaching cylinder. The leaching area is inside the leaching cylinder, and the area between the leaching cylinder and the inner wall of the tower body is the sedimentation area.

[0014] In a second aspect, the present invention further provides a leaching reactor comprising:

[0015] The tower body has an ammonia discharge port at the top, a slag discharge port at the bottom, a clear liquid outlet at the top, and a feed port at the bottom.

[0016] An extraction cylinder is arranged in the tower body;

[0017] A heating body is used to heat the leaching cylinder.

[0018] As a preferred embodiment of the present technical solution, it further comprises a downcomer, which is fixedly arranged on the top of the tower body and sleeved on the outside of the leaching cylinder;

[0019] Preferably, a plurality of second through holes are arranged around the side wall of the downcomer, and the apertures of the second through holes gradually increase from bottom to top.

[0020] As a preferred embodiment of the present invention, a plurality of first through holes are arranged around the side wall of the leaching cylinder, and the apertures of the first through holes gradually increase from bottom to top;

[0021] Preferably, the upper end opening of the leaching cylinder is tapered;

[0022] Preferably, the downcomer is fixedly arranged at the top of the tower body and sleeved on the outside of the tapered portion of the leaching tube.

[0023] As a preferred embodiment of the present technical solution, it further comprises a solid-liquid feeding pipe, the solid-liquid feeding pipe is arranged through the feeding port, and the end of the solid-liquid feeding pipe extends to the interior of the leaching cylinder;

[0024] Preferably, a nozzle is provided at the end of the solid-liquid feeding pipe.

[0025] As a preferred embodiment of the present technical solution, the heating body includes any one of a heat exchange coil and a heat exchange jacket.

[0026] As a preferred embodiment of the present technical solution, it further comprises a deflection baffle, wherein the deflection baffle is arranged in the sedimentation area and mounted on the inner side wall of the tower body, and the angle between the deflection baffle and the inner side wall of the tower body is 5-30°;

[0027] An overflow weir may also be provided inside the tower body, and the overflow weir is located below the clear liquid outlet;

[0028] Preferably, the bottom of the tower body is a conical structure, and the slag discharge port is arranged at the bottom of the conical structure;

[0029] The leaching reactor is used for leaching alkaline earth metal ions, preferably, for leaching calcium ions and magnesium ions.

[0030] In a third aspect, the present invention further provides a system for leaching alkaline earth metal ions comprising the above-mentioned leaching reactor, comprising a heat pump compressor, wherein the inlet end of the heat pump compressor is connected to the ammonia exhaust port, and the outlet end of the heat pump compressor is connected to the inlet end of the heat exchange coil;

[0031] Preferably, the heat pump compressor includes any one of a screw compressor, a centrifugal compressor, a reciprocating compressor and an axial flow compressor.

[0032] As a preferred technical solution, the invention further comprises a clear liquid cooler and an ammonia absorber, wherein the outlet end of the heat exchange coil is connected to the bottom of the ammonia absorber; the inlet end of the clear liquid cooler is connected to the clear liquid outlet, and the outlet end of the clear liquid cooler is connected to the top of the ammonia absorber;

[0033] Preferably, the ammonia absorber comprises any one of an absorption tank, a bubbling tower, a spray tower, a plate tower and a packed tower.

[0034] Finally, the present invention also provides a method for leaching alkaline earth metal ions using the above-mentioned leaching reactor or system for leaching alkaline earth metal ions, comprising the following steps:

[0035] S1. Adding a solid-liquid mixture of alkaline earth metal and ammonium chloride solution into a leaching reactor, the ammonia generated by the reaction overflows from the ammonia outlet after heating, and the solution after the leaching reaction overflows from the top of the leaching reactor, circulates to the tower settling area under the action of the downcomer, undergoes solid-liquid separation in the tower settling area, and the leached supernatant flows out from the supernatant outlet, and the unreacted slag is discharged from the slag discharge port;

[0036] S2. Ammonia gas overflowing from the ammonia outlet enters the heat pump compressor for pressurization and temperature increase, then enters the heat exchange coil, and after heat exchange, enters the ammonia absorber from the bottom; the leached clear liquid is cooled by the clear liquid cooler and then enters the ammonia absorber from the top, where the leached clear liquid absorbs ammonia to obtain CO2 mineralized absorption liquid;

[0037] Preferably, in step S1, during the leaching reaction, the reaction temperature is controlled to be 40-110° C., the time is 1-6 hours, and the molar concentration ratio of calcium and magnesium ions to ammonium ions in the leaching reactor is 1:(2.1-6.0);

[0038] Preferably, in step S2, the compression ratio of the heat pump compressor is 2-8.

[0039] The system and method for leaching alkaline earth metal ions of the present invention have at least the following technical effects:

[0040] 1. The present invention adopts a reaction-separation coupling approach, using ammonium chloride solution as the leaching agent to extract calcium and magnesium ions from alkaline earth metals in an extraction reactor. During the leaching process, ammonia generated by the reaction is evaporated from the solution by evaporation, thereby promoting the reaction.

[0041] 2. The leaching reactor of the present invention comprises a tower body, a leaching tube, and a downcomer, wherein the leaching tube is fixedly mounted inside the tower body via a support, and the downcomer is fixed to the top of the tower body and sleeved onto the outside of the leaching tube. A solid-liquid mixture of alkaline earth metals and ammonium chloride solution enters the leaching tube through a solid-liquid feed pipe, and the solid-liquid mixture forms a circulation within the leaching tube, the downcomer, and the tower body. Calcium and magnesium ions in the alkaline earth metals are leached into the solution by the ammonium chloride solution, generating ammonia gas. The ammonia gas generated by the reaction, heated by a heat exchange coil, can overflow from an ammonia gas outlet at the top of the tower body, while the leaching reaction liquid overflows from the top of the leaching tube and circulates to the tower body settling zone under the action of the downcomer. After solid-liquid separation in the tower body settling zone, the leached supernatant flows out from the supernatant outlet, and the unreacted slag is discharged from the slag outlet. Therefore, the arrangement of the tower body, the leaching cylinder and the downcomer in the leaching reactor of the present invention not only prolongs the action time of the alkaline earth metal and the leaching solution by circulating, thereby improving the separation effect of the slag and the solution, but also can promptly remove the ammonia generated by the reaction, thereby promoting the reaction and improving the leaching rate of calcium in the calcium silicate.

[0042] 3. The leaching reactor of the present invention utilizes ammonium chloride solution to react with calcium-containing silicate raw materials, which can not only extract calcium from the relatively insoluble raw silicate, but also avoid equipment corrosion and acid and alkali consumption problems caused by strong acids such as hydrochloric acid and sulfuric acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0044] FIG1 is a schematic structural diagram of a system for leaching alkaline earth metal ions according to the present invention;

[0045] FIG2 is a schematic structural diagram of the leaching reactor of the present invention.

[0046] Reference numerals:

[0047] 1: Tower body; 2: Extraction tube; 3: Downcomer; 4: Ammonia outlet; 5: Slag outlet; 6: Heat exchange coil; 7: Clear liquid outlet; 8: Solid-liquid feed pipe; 9: Heat pump compressor; 10: Clear liquid cooler; 11: Ammonia absorber; 12: Overflow weir; 13: Baffle; 14: Nozzle. DETAILED DESCRIPTION

[0048] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0049] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular also includes the plural. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0051] Example 1

[0052] As shown in Figures 1-2, this embodiment provides a system for leaching alkaline earth metal ions, including a leaching reactor, and the leaching reactor specifically includes a tower body 1, a leaching cylinder 2 and a downcomer 3, wherein an ammonia outlet 4 is provided at the top of the tower body 1 to timely discharge ammonia generated during the reaction, and a slag outlet 5 is provided at the bottom of the tower body 1 for slag discharge and draining the tower body 1; the leaching cylinder 2 is fixedly arranged inside the tower body 1 through a support, and the upper end opening of the leaching cylinder 2 is tapered to reduce the overflow of the leaching solution, and then circulates to the sedimentation area of ​​the tower body 1 under the action of the downcomer 3; in addition, a heat exchange coil 6 is fixedly provided inside the leaching cylinder 2, and the heat exchange coil 6 can be used to heat the leaching system to evaporate the ammonia generated by the reaction. Ammonia evaporates from the solution; the downcomer 3 is fixedly arranged at the top of the tower body 1 and is sleeved on the outside of the tapered part of the leaching tube 2. The solution after the leaching reaction flows out from the top of the leaching tube 2, and further circulates to the sedimentation area of ​​the tower body 1 under the action of the downcomer 3. After the leaching solution is separated into solid and liquid, the leaching clear liquid flows out from the clear liquid outlet 7 opened on the top of the tower body 1, and the solid residue is discharged from the slag discharge port 5 below the tower body 1. In addition, a solid-liquid feed pipe 8 is also provided at the bottom of the tower body 1. The end of the solid-liquid feed pipe 8 extends to the interior of the leaching tube 2, and a nozzle 14 is provided at the end of the solid-liquid feed pipe 8. The solid-liquid mixture composed of alkaline earth metal and ammonium chloride solution is sprayed into the leaching tube 2 through the solid-liquid feed pipe 8 to facilitate the reaction of alkaline earth metal and sodium chloride solution in the leaching reactor.

[0053] The present invention does not strictly limit the specific shape of the tower body 1. In order to improve the solid-liquid separation effect, the tower body 1 can be set to a conical structure. Specifically, the bottom of the tower body 1 is a conical structure, and the slag discharge port 5 is set at the bottom of the conical structure to facilitate the discharge of the tower body 1; the top of the tower body 1 is also a conical structure, and the diameter of the small end of the conical structure is consistent with the diameter of the main structure of the tower body 1, thereby providing sufficient accommodation space for the leaching clear liquid.

[0054] The leaching system of this embodiment also includes a heat pump compressor 9, a clear liquid cooler 10, and an ammonia absorber 11. The inlet end of the heat pump compressor 9 is connected to the ammonia exhaust port 4, the outlet end of the heat pump compressor 9 is connected to the inlet end of the heat exchange coil 6, and the outlet end of the heat exchange coil 6 is connected to the bottom of the ammonia absorber 11. The configuration of the heat pump compressor 9 realizes the recovery and utilization of the heat of the discharged ammonia, greatly reducing the energy consumption of the treatment system. The inlet end of the clear liquid cooler 10 is connected to the clear liquid outlet 7, and the outlet end of the clear liquid cooler 10 is connected to the top of the ammonia absorber 11. After condensing in the clear liquid cooler 10, the leached clear liquid enters the ammonia absorber 11 from the top of the ammonia absorber 11. After heat exchange in the heat exchange coil 6, the ammonia enters the ammonia absorber 11 from the bottom of the ammonia absorber 11, leaching, cleaning and absorbing the ammonia, thereby obtaining an alkaline calcium chloride and magnesium chloride CO2 mineralization absorption liquid. The setting of this system not only improves the leaching rate of calcium and magnesium ions in alkaline earth metals, but also the prepared CO2 mineralization absorption liquid can be directly used for CO2 capture and utilization.

[0055] On the basis of the above technical solution, it is further preferred that a plurality of first through holes are arranged around the side wall of the leaching cylinder 2, and the aperture of the first through holes gradually increases from bottom to top, and the reaction material is sprayed into the leaching cylinder 2 from the bottom, forming an upward circulation in the leaching cylinder 2. At the same time, the reaction material can overflow from the plurality of first through holes on the side wall and the top of the leaching cylinder 2 to the sedimentation area of ​​the tower body 1 (the annular area between the tower body 1 and the leaching cylinder 2); in addition, a plurality of second through holes are also arranged around the side wall of the downcomer 3, and the aperture of the second through holes gradually increases from bottom to top, and its function is also to drain the material overflowing from the upper part of the leaching cylinder 2 to the sedimentation area of ​​the tower body 1.

[0056] In addition, in this embodiment, an overflow weir 12 is further provided inside the tower body 1. Specifically, the overflow weir 12 is located below the clear liquid outlet 7 to further improve the solid-liquid separation effect.

[0057] On the basis of the above technical solution, more preferably, a plurality of downward-inclined deflection baffles 13 are spirally arranged on the inner side wall of the tower body 1, and the angle between the deflection baffles 13 and the inner side wall of the tower body 1 is 5-30°. The provision of the deflection baffles 13 prolongs the action time of the leaching agent and the alkaline earth metal, thereby improving the leaching efficiency and leaching rate of calcium and magnesium ions.

[0058] In this embodiment, the heat pump compressor 9 includes but is not limited to a screw compressor, a centrifugal compressor, a reciprocating compressor and an axial flow compressor; and the ammonia absorber 11 includes but is not limited to an absorption tank, a bubble tower, a spray tower, a plate tower and a packed tower.

[0059] In another specific embodiment of the present invention, the leaching reactor is divided into an leaching area and a settling area by an leaching cylinder 2 in the leaching reactor. Specifically, the total volume of the leaching reactor is 20L, and the height-to-diameter ratio is 1.6. The leaching area is 8L, and the leaching area is provided with a built-in heat exchange coil 6; the heat pump compressor 9 is a screw compressor; the clear liquid cooler 10 is a shell and tube heat exchanger with a heat exchange area of ​​5m 2 ; Ammonia absorber 11 is a spray tower with a height of 1.5 meters. The tower is filled with ball ring packing with a packing layer height of 0.6 meters.

[0060] Example 2

[0061] The most preferred leaching system was used to treat wollastonite collected from Hubei Province. The wollastonite was first ground to 100 mesh, and then its main composition was determined by melt X-ray fluorescence spectrometry. The results are shown in Table 1.

[0062] Table 1 Main element composition of wollastonite

[0063]

[0064] The solid-liquid mixture of wollastonite and ammonium chloride solution is added to the leaching reactor at a rate of 2.0 kg / h, comprising 200 g / h of wollastonite and 1.8 kg / h of ammonium chloride solution (15.2% by mass). The leaching system is heated to 95°C by heat exchange coil 6 within the leaching drum 2 of the leaching reactor. Ammonia gas generated by the reaction is discharged through the ammonia exhaust port and then enters the heat pump compressor 9 for pressure increase to 0.28 MPa. The pressurized gas temperature rises to 152.1°C. After heat exchange in the leaching reactor heat exchange coil 6, it is cooled to 105°C and enters the ammonia absorber 11 from the bottom. The supernatant in the leaching reactor is cooled to 40°C by supernatant cooler 10 and enters the ammonia absorber 11 from the top, where it is countercurrently contacted with the ammonia gas entering from the bottom. The total hydraulic retention time (HRT) of the reaction materials in the leaching reactor is 4 hours.

[0065] The mass fraction of calcium in the leaching solution was determined to be 2.07%, and the extraction rate of calcium in wollastonite was calculated to be 63%.

[0066] Example 3

[0067] The most preferred leaching system was used to treat concrete collected from a construction site in Beijing. Wollastonite was first ground to 100 mesh, and then its main composition was determined by melt X-ray fluorescence spectrometry. The results are shown in Table 2.

[0068] Table 2 Main element composition of concrete

[0069]

[0070] After mixing the concrete with the ammonium chloride solution, the mixture was added to the leaching reactor at a rate of 2.0 kg / h, with 200 g / h of concrete and 1.8 kg / h of ammonium chloride solution (15.2% by mass). The leaching system was heated to 105°C by the heat exchange coil 6 within the leaching reactor's leaching drum 2. The ammonia produced by the reaction was discharged through the ammonia exhaust port and then entered the heat pump compressor 9 to be pressurized to 0.284 MPa. The pressurized gas temperature rose to 155.4°C. After heat exchange in the leaching reactor's heat exchange coil 6, it was cooled to 115°C and entered the ammonia absorber 11 from the bottom. The supernatant in the leaching reactor was cooled to 40°C by the supernatant cooler 10 and entered the ammonia absorber 11 from the top, where it came into countercurrent contact with the ammonia gas entering from the bottom. The total hydraulic retention time (HRT) of the reaction materials in the leaching reactor was 4 hours.

[0071] The mass fraction of calcium in the extract from the leaching reactor was determined to be 1.02%, and the extraction rate of calcium in the concrete was calculated to be 61%.

[0072] Example 4

[0073] The most preferred leaching system was used to treat steel slag from a steel plant in Tangshan. The slag was first ground to 200 mesh, and then its main composition was determined by melt X-ray fluorescence spectrometry. The results are shown in Table 3.

[0074] Table 3 Main element composition of steel slag from a steel plant in Tangshan

[0075]

[0076] After mixing the steel slag and ammonium chloride solution, the mixture is added to the leaching reactor at a flow rate of 2.0 kg / h, with 200 g / h of steel slag and 1.8 kg / h of ammonium chloride solution (with a mass fraction of 15.2%). The leaching system is heated to 95°C by the heat exchange coil 6 in the leaching tube 2 of the leaching reactor. The ammonia produced by the reaction is discharged through the ammonia exhaust port and enters the heat pump compressor 9 to be pressurized to 0.26 MPa. The pressurized gas temperature rises to 135°C. After heat exchange in the leaching reactor heat exchange coil 6, it is cooled to 115°C and enters the ammonia absorber 11 from the bottom. The supernatant in the leaching reactor is cooled to 40°C by the supernatant cooler 10 and enters the ammonia absorber 11 from the top, where it contacts the ammonia gas entering from the bottom in countercurrent. The total hydraulic retention time (HRT) of the reaction materials in the leaching reactor is 4 hours.

[0077] The mass fraction of calcium in the extract from the leaching reactor was determined to be 1.81%, and the mass fraction of magnesium was 0.234%. The extraction rates of calcium and magnesium in the steel slag were calculated to be 65% and 63%.

[0078] Comparative Example 1

[0079] The wollastonite in Example 2 was treated using a conventional kettle agitator. The specific treatment method is as follows:

[0080] 200 g of wollastonite and 1.8 kg of 15.2% ammonium chloride solution were added to the reactor. The temperature of the leaching system was controlled at 95°C and the reaction time was 4 h.

[0081] After the reaction is completed, the leaching liquid is discharged from the upper discharge port, and the slag is discharged from the lower discharge port.

[0082] The mass fraction of calcium in the leaching solution was determined to be 1.48%, and the extraction rate of calcium in wollastonite was calculated to be 45%.

[0083] Comparative Example 2

[0084] The concrete in Example 3 was processed using a conventional kettle mixer, and the specific processing method was as follows:

[0085] 200g of concrete and 1.8kg of 15.2% ammonium chloride solution were added to the reactor, the temperature of the leaching system was controlled at 105°C, and the reaction was carried out for 4h.

[0086] After the reaction is completed, the leaching liquid is discharged from the upper discharge port, and the slag is discharged from the lower discharge port.

[0087] The mass fraction of calcium in the leaching solution was determined to be 0.719%, and the calcium extraction rate in the concrete was calculated to be 43%.

[0088] Comparative Example 3

[0089] The slag reactor disclosed in patent CN115779844A was used to treat the wollastonite in Example 2. The specific treatment method is as follows:

[0090] S1. Take 200 g of wollastonite and 1.8 kg of 15.2% ammonium chloride solution, mix them in a slurry mixing tank, and add them into a horizontal cylinder inner cylinder reactor (22 cm in diameter and 197 cm in length) through the feed port. The horizontal cylinder starts to rotate at 50 rpm.

[0091] S2. The temperature of the mixed slurry is controlled at 95°C by the temperature control jacket. After the discharge buffer tank reaches a certain liquid level, the ultrasonic power is turned on at 200W, the aperture of the filter is 200 mesh, and the reaction is carried out for 4 hours;

[0092] S3. After the reaction is completed, the slurry is discharged from the discharge port and filtered, and the filtered clear liquid is pumped into the mineralization tower.

[0093] The mass fraction of calcium in the clear liquid was determined to be 1.28%, and the extraction rate of calcium from wollastonite was calculated to be 39%.

[0094] Comparative Example 4

[0095] The concrete in Example 3 was treated using the slag reactor disclosed in patent CN115779844A. The specific treatment method is as follows:

[0096] S1. Take 200g of concrete and 1.8kg of 15.2% ammonium chloride solution, mix them in a slurry mixing tank, and then add them into the inner cylinder reactor (22cm in diameter and 197cm in length) of a horizontal cylinder through the feed port. The horizontal cylinder starts to rotate at 50rpm.

[0097] S2. The temperature of the mixed slurry is controlled at 105°C by the temperature control jacket. After the discharge buffer tank reaches a certain liquid level, the ultrasonic power is turned on at 200W, the aperture of the filter is 200 mesh, and the reaction is carried out for 4 hours;

[0098] S3. After the reaction is completed, the slurry is discharged from the discharge port and filtered, and the filtered clear liquid is pumped into the mineralization tower.

[0099] The mass fraction of calcium in the clear liquid was determined to be 0.635%, and the extraction rate of calcium in the concrete was calculated to be 38%.

[0100] In summary, the use of the leaching system of the present invention for extracting calcium and magnesium ions from alkaline earth metals not only shortens the leaching time and reduces energy consumption, but also improves the leaching rate of calcium from calcium-containing silicates.

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An extraction reactor, characterized in that, Comprising: A tower body (1) with an ammonia discharge port (4) opened at its top, a slag discharge port (5) opened at its bottom, a clear liquid outlet (7) opened above the tower body (1), and a feed port opened below the tower body (1); An extraction cylinder (2) disposed inside the tower body (1), and the extraction reactor can be divided into an extraction area and a sedimentation area by the extraction cylinder (2). The inside of the extraction cylinder (2) is the extraction area, and the area between the extraction cylinder (2) and the inner wall of the tower body (1) is the sedimentation area.

2. An extraction reactor, characterized in that, Comprising: A tower body (1) with an ammonia discharge port (4) opened at its top, a slag discharge port (5) opened at its bottom, a clear liquid outlet (7) opened above the tower body, and a feed port opened below the tower body (1); An extraction cylinder (2) disposed inside the tower body (1); A heating body for heating the extraction cylinder (2).

3. The leaching reactor according to any one of claims 1 or 2, characterized in that It further includes a downcomer (3) fixedly arranged at the top inside the tower body (1) and sleeved outside the extraction cylinder (2); Preferably, a plurality of second through holes are circumferentially arranged on the side wall of the downcomer (3), and the aperture of the second through holes gradually increases from bottom to top.

4. The leaching reactor according to claim 3, characterized in that, A plurality of first through holes are circumferentially arranged on the side wall of the extraction cylinder (2), and the aperture of the first through holes gradually increases from bottom to top; Preferably, the upper end opening of the extraction cylinder (2) is of a gradually shrinking type; Preferably, the downcomer (3) is fixedly arranged at the top inside the tower body (1) and sleeved outside the gradually shrinking part of the extraction cylinder (2).

5. The leaching reactor according to any one of claims 1 or 2, characterized in that, It further includes a solid-liquid feed pipe (8) passing through the feed port, and the end of the solid-liquid feed pipe (8) extends into the inside of the extraction cylinder (2); Preferably, a nozzle (14) is arranged at the end of the solid-liquid feed pipe (8).

6. The leaching reactor according to claim 2, wherein The heating body includes any one of a heat exchange coil (6) and a heat exchange jacket.

7. The leaching reactor according to any one of claims 1 or 2, characterized in that It further includes a baffle (13) disposed in the sedimentation area and installed on the inner side wall of the tower body (1), and the included angle between the baffle (13) and the inner side wall of the tower body (1) is 5 - 30°; An overflow weir (12) can also be arranged inside the tower body (1), and the overflow weir (12) is located below the clear liquid outlet (7); Preferably, the bottom of the tower body (1) is of a conical structure, and the slag discharge port (5) is arranged at the bottom of the conical structure; The extraction reactor is used for extracting alkaline earth metal ions, preferably for extracting calcium ions and magnesium ions.

8. A system for leaching alkaline earth metal ions using the leaching reactor according to any one of claims 1-7, characterized in that, Comprising a heat pump compressor (9), the inlet end of the heat pump compressor (9) is communicated with the ammonia discharge port (4), and the outlet end of the heat pump compressor (9) is communicated with the inlet end of the heat exchange coil (6); Preferably, the heat pump compressor (9) includes any one of a screw compressor, a centrifugal compressor, a reciprocating compressor, and an axial flow compressor.

9. The system for leaching alkaline earth metal ions according to claim 8, wherein, It further includes a clear liquid cooler (10) and an ammonia absorber (11), the outlet end of the heat exchange coil (6) is communicated with the bottom of the ammonia absorber (11); the inlet end of the clear liquid cooler (10) is communicated with the clear liquid outlet (7), and the outlet end of the clear liquid cooler (10) is communicated with the top of the ammonia absorber (11); Preferably, the ammonia absorber (11) includes any one of an absorption tank, a bubble column, a spray column, a plate column, and a packed column.

10. A method for leaching alkaline earth metal ions using the leaching reactor according to any one of claims 1-7 or the system for leaching alkaline earth metal ions according to any one of claims 8-9, characterized in that, The method includes the following steps: S1. Add the solid-liquid mixture of alkaline earth metal and ammonium chloride solution into the leaching reactor. The generated ammonia overflows from the ammonia discharge port (4) after heating. The solution after the leaching reaction overflows from the top of the leaching reactor, and under the action of the downcomer (3), it circulates to the settling zone of the tower body (1), and is subjected to solid-liquid separation in the settling zone of the tower body (1). The leaching clear liquid flows out from the clear liquid outlet (7), and the unreacted slag is discharged from the slag discharge port (5); S2. The ammonia overflowing from the ammonia discharge port (4) enters the heat pump compressor (9) to be pressurized and heated, then enters the heat exchange coil (6), and after heat exchange, enters the ammonia absorber (11) from the bottom; the leaching clear liquid is cooled by the clear liquid cooler (10) and then enters the ammonia absorber (11) from the top. The leaching clear liquid absorbs ammonia to obtain the CO2 mineralization absorption liquid; Preferably, in step S1, during the leaching reaction, the reaction temperature is controlled to be 40 - 110 °C, the time is 1 - 6 h, and in the leaching reactor, the molar concentration ratio of the sum of calcium and magnesium ions to ammonium ions is 1:(2.1 - 6.0); Preferably, in step S2, the compression ratio of the heat pump compressor (9) is 2 - 8.

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