A 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, including a leaching reactor, the leaching reactor including a tower body, a leaching tube and a downcomer; an ammonia discharge port is provided at the top of the tower body, and a slag discharge port is provided at the bottom of the tower body; the leaching tube is fixedly arranged inside the tower body through a support, and a heat exchange coil is fixed inside the leaching tube; the downcomer is fixedly arranged at the top of the tower body and sleeved on the outside of the leaching tube; a clear liquid outlet is provided above the tower body, and a solid-liquid feed pipe is provided below the tower body, and the end of the solid-liquid feed pipe extends to the inside of the leaching tube. The present invention adopts the idea of ​​reaction-separation coupling, and uses ammonium chloride solution as the leaching agent, which not only prolongs the action time of alkaline earth metals and leaching liquid by circulating, but also can timely remove ammonia generated by the reaction, promotes the reaction, and improves the leaching rate of calcium in calcium silicate.

Description

Technical Field

[0001] The 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] Utilize calcium and magnesium raw materials from nature and industrial solid waste, and CO2 emitted by industry 2 The reaction to prepare calcium carbonate and magnesium carbonate can not only realize CO 2 It can capture and utilize calcium and magnesium resources, and can replace the existing industrial process of limestone decomposition to prepare precipitated calcium carbonate, reducing carbon emissions from limestone mining and processes.

[0003] At present, the use of alkaline earth metals containing calcium and magnesium in nature and industrial solid waste as raw materials and industrial emissions of CO 2 A feasible technical route for preparing precipitated carbonate is to first extract calcium and magnesium from the raw materials into solution, and then 2 The extract is introduced into the gas-liquid absorption reaction to obtain precipitated calcium carbonate. In the prior art, there are a large number of literatures and patents reporting on the calcium and magnesium components in different extraction raw materials, as well as the 2 Specific technical solutions for mineralization reactions can be roughly divided into the following three types.

[0004] First, use acid to dissolve and extract calcium and magnesium components, and use alkali to assist CO 2 Reacts with calcium and magnesium. For example, patent CN101134155A, literature Ding W, Fu L, Ouyang J, et al. (2014) CO 2 Mineral sequestration by wollastonite carbonation. Physics and Chemistry of Minerals 41(7):489-496 reported that inorganic acids (HCl, H 2 SO4、HNO 3 ) and organic acids (HCOOH, CH 3 COOH) as an auxiliary agent to leaching serpentine, and mineralization of CO under alkaline conditions 2 .

[0005] Second, use salt to decompose to obtain acid and alkali, use acid solution to extract calcium and magnesium components, and use alkali to assist CO 2React with calcium and magnesium, and the salt generated after the reaction is pyrolyzed again and recycled. For example, the patent CN104284707A reports that pyrolysis of hydrated magnesium chloride generates hydrochloric acid and basic magnesium chloride / magnesium hydroxide, and hydrochloric acid is used to extract the calcium and magnesium components in the silicate, and basic magnesium chloride / magnesium hydroxide is used to adjust the alkalinity of the solution for CO 2 Another example is the reaction of producing carbonates; for example, Gretta LarisaAurora Arce Ferrufino's team at the Brazilian Space Research Institute reported the use of serpentine as raw material, hydrochloric acid as leaching agent, and ammonia as precipitant to mineralize CO 2 The mineralization mother liquor obtained is NH 4 The mother liquor can be evaporated, concentrated and crystallized at high temperature and then thermally decomposed to recover HCl and NH 3 The main problems with this route are that salt usually needs to be pyrolyzed or electrolyzed to prepare acids and bases, which consumes a lot of energy. The pyrolysis temperature is usually high, and the performance requirements for equipment corrosion resistance are high. It also involves a large amount of solid / molten salt operations, and the process is complex and difficult to engineer.

[0006] Third, a recyclable solvent or solution is used to extract and dissolve the calcium and magnesium components, and the solvent or solution can be used in the presence of CO 2 Regeneration during the reaction. 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 that of silicic acid but lower than that of carbonic acid. For example, patent CN101134155A proposes to leach calcium-containing silicates with acetic acid to obtain a calcium acetate solution, which is further leached in CO 2 The atmosphere is mineralized to generate calcium carbonate and acetic acid, and acetic acid is extracted by adding organic solvents such as tributyl phosphate (TBP) to promote the forward mineralization reaction, and the acetic acid is recycled after stripping; another example is the route reported in patents CN106745146A and CN105197975A, which uses ammonium chloride solution as a circulating solution to extract calcium contained in calcium silicate in steel slag. This route has a relatively simple process flow, 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, and microwave irradiation is used as an auxiliary means in the leaching process. Although the 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 is different, which brings uncertainty to the treatment of steel slag. Patent CN115779844A discloses a slag reactor, which mainly prolongs the action time of steel slag and leaching liquid by setting a horizontal cylinder, spikes and baffles, and avoids the generation of an inert layer on the surface of 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, which not only prolongs the action time of alkaline earth metal and leaching solution by circulating, but also can timely remove ammonia generated by the reaction, promotes the reaction, and improves 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 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 tube;

[0019] Preferably, a plurality of second through holes are disposed 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 technical solution, 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 tube 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 baffle plate, wherein the baffle plate is arranged in the settling area and mounted on the inner side wall of the tower body, and the angle between the baffle plate 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 outlet, 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 communicated with the bottom of the ammonia absorber; the inlet end of the clear liquid cooler is communicated with the clear liquid outlet, and the outlet end of the clear liquid cooler is communicated with 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 the 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, the solution after the leaching reaction overflows from the top of the leaching reactor, circulates to the tower sedimentation area under the action of the downcomer, undergoes solid-liquid separation in the tower sedimentation area, the leached clear liquid flows out from the clear liquid outlet, and the unreacted slag is discharged from the slag outlet;

[0036] S2, the ammonia gas overflowing from the ammonia outlet enters the heat pump compressor for pressurization and temperature increase, and then enters the heat exchange coil. After heat exchange, it enters the ammonia absorber from the bottom; the leached clear liquid is cooled by the clear liquid cooler and enters the ammonia absorber from the top. The leached clear liquid absorbs ammonia to obtain CO 2 Mineralized absorption fluid;

[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 the idea of ​​reaction-separation coupling, uses ammonium chloride solution as the leaching agent, and leaches calcium and magnesium ions in alkaline earth metals in the leaching reactor. During the leaching, the 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 cylinder and a downcomer, wherein the leaching cylinder is fixedly arranged inside the tower body through a support, and the downcomer is fixed at the top of the tower body and sleeved on the outside of the leaching cylinder. The solid-liquid mixture of alkaline earth metal and ammonium chloride solution enters the leaching cylinder through a solid-liquid feed pipe, and the solid-liquid mixture forms a circulation in the leaching cylinder, the downcomer and the tower body. The calcium and magnesium ions in the alkaline earth metal are leached into the solution by the ammonium chloride solution and generate ammonia. The ammonia generated by the reaction can overflow from the ammonia outlet at the top of the tower body under the heating of the heat exchange coil, and the leaching reaction liquid overflows from the top of the leaching cylinder, circulates to the tower body sedimentation area under the action of the downcomer, and is separated into solid and liquid in the tower body sedimentation area. The leached clear liquid flows out from the clear liquid 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 timely 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 realize the extraction of calcium from the relatively insoluble raw silicate, but also avoid the equipment corrosion and acid-base 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 implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 It is a schematic diagram of the structure of the alkaline earth metal ion leaching system of the present invention;

[0045] Figure 2 It is a schematic diagram of the structure of the leaching reactor of the present invention.

[0046] Reference numerals:

[0047] 1: tower body; 2: extraction cylinder; 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 are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those 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 form also includes the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this description, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0050] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Example 1

[0052] like Figure 1-2 As shown, the present 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 to discharge slag and drain 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 arranged inside the leaching cylinder 2, and the setting of the heat exchange coil 6 can be used to heat the leaching system to evaporate the ammonia generated by the reaction from 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 at the bottom of the tower body 1. In addition, a solid-liquid feeding pipe 8 is also arranged at the bottom of the tower body 1, and the end of the solid-liquid feeding pipe 8 extends to the inside of the leaching tube 2, and a nozzle 14 is arranged at the end of the solid-liquid feeding pipe 8. The solid-liquid mixture composed of the alkaline earth metal and the ammonium chloride solution is sprayed into the leaching tube 2 through the solid-liquid feeding pipe 8, so that the alkaline earth metal and the sodium chloride solution react 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 mouth 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, wherein the inlet end of the heat pump compressor 9 is connected to the ammonia outlet 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 setting of the heat pump compressor 9 realizes the recovery and utilization of the heat of the discharged ammonia, which greatly reduces 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. The leached clear liquid enters the ammonia absorber 11 from the top of the ammonia absorber 11 after condensation by the clear liquid cooler 10, and the ammonia after heat exchange by the heat exchange coil 6 enters the ammonia absorber 11 from the bottom of the ammonia absorber 11, and the ammonia is absorbed by the leaching, cleaning and absorption, thereby obtaining alkaline calcium chloride, magnesium chloride CO 2 The setting of this system not only improves the leaching rate of calcium and magnesium ions in alkaline earth metals, but also the prepared CO 2 The mineralized absorption liquid can be directly used for CO 2 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 to form 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 of the leaching cylinder 2 and the top 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 guide 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 downwardly inclined baffles 13 are spirally arranged on the inner wall of the tower body 1, and the angle between the baffle 13 and the inner wall of the tower body 1 is 5-30°. The setting of the baffle 13 prolongs the action time of the leaching agent and the alkaline earth metal, and improves 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 bubbling 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 a 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, wherein the leaching area is 8L, and the leaching area is provided with a built-in heat exchange coil 6; the heat pump compressor 9 adopts a screw compressor; the clear liquid cooler 10 is a shell and tube heat exchanger with a heat exchange area of ​​5m 2 ; The ammonia absorber 11 is a spray tower with a height of 1.5 meters. The tower is filled with ball ring packing and the packing layer height is 0.6 meters.

[0060] Example 2

[0061] The most preferred leaching system was used to process 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 flow rate of 2.0 kg / h, wherein wollastonite is 200 g / h and ammonium chloride solution is 1.8 kg / h (mass fraction of ammonium chloride is 15.2%). The leaching system is heated to 95°C through the heat exchange coil 6 in the leaching cylinder 2 of the leaching reactor. The ammonia generated by the reaction is discharged through the ammonia exhaust port and enters the heat pump compressor 9 to be pressurized to 0.28 MPa. The temperature of the pressurized gas is increased to 152.1°C. After entering the heat exchange coil 6 of the leaching reactor for heat exchange, it is cooled to 105°C and enters the ammonia absorber 11 from the bottom; the leaching clear liquid in the leaching reactor is cooled to 40°C through the clear liquid cooler 10, enters the ammonia absorber 11 from the top, and contacts with the ammonia entering from the bottom in countercurrent. The total hydraulic retention time (HRT) of the reaction raw 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 above most preferred leaching system was used to treat concrete collected from a construction site in Beijing. First, the wollastonite was ground to 100 mesh, and then its main composition was determined by melting X-ray fluorescence spectrometry. The results are shown in Table 2.

[0068] Table 2 Main element composition of concrete

[0069]

[0070] After the concrete and the ammonium chloride solution are mixed, they are added to the leaching reactor at a flow rate of 2.0 kg / h, wherein the concrete is 200 g / h and the ammonium chloride solution is 1.8 kg / h (the mass fraction of ammonium chloride is 15.2%). The leaching system is heated to 105°C through the heat exchange coil 6 in the leaching cylinder 2 of the leaching reactor. The ammonia generated by the reaction is discharged through the ammonia exhaust port and enters the heat pump compressor 9 to be pressurized to 0.284 MPa. The temperature of the pressurized gas is increased to 155.4°C. After entering the heat exchange coil 6 of the leaching reactor for heat exchange, it is cooled to 115°C and enters the ammonia absorber 11 from the bottom; the leaching clear liquid in the leaching reactor is cooled to 40°C through the clear liquid cooler 10, enters the ammonia absorber 11 from the top, and contacts with the ammonia entering from the bottom in countercurrent. The total hydraulic retention time (HRT) of the reaction raw materials in the leaching reactor is 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 steel slag was first ground to 200 mesh, and then its main composition was determined by melting 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 the steel slag and the ammonium chloride solution are mixed, they are added to the leaching reactor at a flow rate of 2.0 kg / h, wherein the steel slag is 200 g / h and the ammonium chloride solution is 1.8 kg / h (the mass fraction of ammonium chloride is 15.2%). The leaching system is heated to 95°C through the heat exchange coil 6 in the leaching cylinder 2 of the leaching reactor. The ammonia generated 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 temperature of the pressurized gas is increased to 135°C. After entering the heat exchange coil 6 of the leaching reactor for heat exchange, it is cooled to 115°C and enters the ammonia absorber 11 from the bottom; the leaching clear liquid in the leaching reactor is cooled to 40°C through the clear liquid cooler 10, enters the ammonia absorber 11 from the top, and contacts with the ammonia entering from the bottom in countercurrent. The total hydraulic retention time (HRT) of the reaction raw 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, and the specific treatment method was 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 clear 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 continued for 4h.

[0086] After the reaction is completed, the leaching clear 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 extraction rate of calcium 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 the inner cylinder reactor (22 cm in diameter and 197 cm in length) of a horizontal cylinder through the feed port. The horizontal cylinder starts to rotate at 50 rpm.

[0091] S2. The temperature of the mixed slurry is controlled to 95°C by the temperature control jacket. After the discharge buffer tank reaches a certain liquid level, ultrasound is turned on. The ultrasonic power is 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 in 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 to 105°C by the temperature control jacket. After the discharge buffer tank reaches a certain liquid level, ultrasound is turned on. The ultrasonic power is 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by 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. A leaching reactor, characterized in that: include: The tower body (1) has an ammonia discharge port (4) at the top and a slag discharge port (5) at the bottom. A clear liquid outlet (7) is provided above the tower body (1), and a feed port is provided below the tower body (1); An extraction cylinder (2) is arranged in the tower body (1), and the extraction reactor is divided into an extraction area and a sedimentation area by the extraction cylinder (2), wherein 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; It also comprises a downcomer (3), wherein the downcomer (3) is fixedly arranged at the top of the tower body (1) and sleeved on the outside of the leaching cylinder (2); A plurality of second through holes are arranged around the side wall of the downcomer (3), and the apertures of the second through holes gradually increase from bottom to top; A plurality of first through holes are arranged around the side wall of the leaching cylinder (2), and the diameters of the first through holes gradually increase from bottom to top; The upper end opening of the leaching cylinder (2) is tapered; The downcomer (3) is fixedly arranged at the top of the tower body (1) and sleeved on the outside of the tapered portion of the leaching tube (2); It also comprises a baffle plate (13), the baffle plate (13) being arranged in the sedimentation area and mounted on the inner side wall of the tower body (1), and the included angle between the baffle plate (13) and the inner side wall of the tower body (1) is 5°. o -30 o ; An overflow weir (12) is provided inside the tower body (1), and the overflow weir (12) is located below the clear liquid outlet (7); The bottom of the tower body (1) is in a conical structure, and the slag discharge port (5) is arranged at the bottom of the conical structure; The leaching reactor is used to leach alkaline earth metal ions.

2. A leaching reactor, characterized in that: include: The tower body (1) has an ammonia discharge port (4) at the top, a slag discharge port (5) at the bottom, a clear liquid outlet (7) at the top of the tower body, and a feed port at the bottom of the tower body (1); An extraction cylinder (2) is arranged in the tower body (1); A heating body, used for heating the leaching cylinder (2); It also comprises a downcomer (3), wherein the downcomer (3) is fixedly arranged at the top of the tower body (1) and sleeved on the outside of the leaching cylinder (2); A plurality of second through holes are arranged around the side wall of the downcomer (3), and the apertures of the second through holes gradually increase from bottom to top; A plurality of first through holes are arranged around the side wall of the leaching cylinder (2), and the diameters of the first through holes gradually increase from bottom to top; The upper end opening of the leaching cylinder (2) is tapered; The downcomer (3) is fixedly arranged at the top of the tower body (1) and sleeved on the outside of the tapered portion of the leaching tube (2); It also comprises a baffle plate (13), the baffle plate (13) being arranged in the sedimentation area and mounted on the inner side wall of the tower body (1), and the included angle between the baffle plate (13) and the inner side wall of the tower body (1) is 5°. o -30 o ; An overflow weir (12) is provided inside the tower body (1), and the overflow weir (12) is located below the clear liquid outlet (7); The bottom of the tower body (1) is in a conical structure, and the slag discharge port (5) is arranged at the bottom of the conical structure; The leaching reactor is used to leach alkaline earth metal ions.

3. The leaching reactor according to any one of claims 1 or 2, characterized in that: It also comprises a solid-liquid feed pipe (8), the solid-liquid feed pipe (8) is arranged through the feed port, and the end of the solid-liquid feed pipe (8) extends to the interior of the leaching cylinder (2); A nozzle (14) is provided at the end of the solid-liquid feeding pipe (8).

4. The leaching reactor according to claim 2, characterized in that: The heating body comprises any one of a heat exchange coil (6) and a heat exchange jacket.

5. A system for leaching alkaline earth metal ions using the leaching reactor according to claim 4, characterized in that: It comprises a heat pump compressor (9), wherein the inlet end of the heat pump compressor (9) is connected to the ammonia outlet (4), and the outlet end of the heat pump compressor (9) is connected to the inlet end of the heat exchange coil (6); The heat pump compressor (9) comprises any one of a screw compressor, a centrifugal compressor, a reciprocating compressor and an axial compressor.

6. The system for leaching alkaline earth metal ions according to claim 5, characterized in that: It also includes a clear liquid cooler (10) and an ammonia absorber (11), wherein the outlet end of the heat exchange coil (6) is in communication with the bottom of the ammonia absorber (11); the inlet end of the clear liquid cooler (10) is in communication with the clear liquid outlet (7), and the outlet end of the clear liquid cooler (10) is in communication with the top of the ammonia absorber (11); The ammonia absorber (11) comprises any one of an absorption tank, a bubbling tower, a spray tower, a plate tower and a packed tower.

7. A method for leaching alkaline earth metal ions using the system for leaching alkaline earth metal ions according to claim 6, characterized in that: The following steps are involved: S1, adding a solid-liquid mixture of alkaline earth metal and ammonium chloride solution into a leaching reactor, and the ammonia generated by the reaction overflows from the ammonia outlet (4) after being heated, and the solution after the leaching reaction overflows from the top of the leaching reactor, circulates to the sedimentation area of ​​the tower body (1) under the action of the downcomer (3), undergoes solid-liquid separation in the sedimentation area of ​​the tower body (1), and the leached clear liquid flows out from the clear liquid outlet (7), and the unreacted slag is discharged from the slag outlet (5); S2, ammonia gas overflowing from the ammonia outlet (4) enters the heat pump compressor (9) for pressurization and temperature increase, and then enters the heat exchange coil (6). After heat exchange, it enters the ammonia absorber (11) from the bottom; the leached clear liquid is cooled by the clear liquid cooler (10), and then enters the ammonia absorber (11) from the top. The leached clear liquid absorbs ammonia gas to obtain a CO2 mineralization absorption liquid; 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); In step S2, the compression ratio of the heat pump compressor (9) is 2-8.

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