Method and system for separating calcined dolomite from dolomite

Abstract

The invention relates to a dolomite calcined dolomite separation method and system, and belongs to the technical field of dolomite calcined dolomite separation, the method comprises the following steps: digesting dolomite calcined dolomite to obtain a first emulsion; spraying out the carbon dioxide mixed gas with set pressure by using a spraying method so as to form a high-speed carbon dioxide mixed gas jet flow; under the action of negative pressure generated around the high-speed carbon dioxide mixed gas jet flow, the first emulsion is sucked and subjected to a first carbonization reaction with the carbon dioxide mixed gas with set pressure intensity, and second emulsion is obtained. According to the characteristics of calcium and magnesium separation and carbonization, negative pressure is formed under the blowing condition of carbon dioxide compressed gas by using a spraying method, and the negative pressure drives the calcined dolomite emulsion and the carbon dioxide mixed gas to be rapidly mixed and collided, so that the purpose of efficient carbonization is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of dolomite calcined white separation, and in particular to a method and system for separating calcined dolomite. Background Art

[0002] The main components of dolomite are calcium carbonate and magnesium carbonate, which can be used as raw materials for smelting magnesium metal and extracting magnesium oxide. When using dolomite as raw material to produce magnesium metal by aluminothermic process, the dolomite must first be separated into calcium and magnesium by carburization, and then the magnesium oxide is mixed with aluminum powder and reduced. In actual production, carburization is one of the key processes for separating calcium and magnesium. This process requires a large amount of carbon dioxide gas, which affects the industrial production cost to a certain extent.

[0003] At present, the process of calcium-magnesium separation by dolomite carbonization mainly includes: calcining dolomite at high temperature to obtain calcined dolomite, the main components of which are magnesium oxide and calcium oxide; obtaining an emulsion through digestion and pulping; introducing CO2 into the emulsion in a carbonization tower for carbonization to convert Ca(OH)2 into CaCO3 and then filter and remove the precipitate. The filtrate is refined heavy magnesium water, mainly containing Mg(HCO3)2. After pyrolysis, filtration and calcination of the filtrate, basic magnesium carbonate, magnesium oxide and other products can be obtained. In this process of calcium-magnesium separation, emulsion carbonization is an important step, which directly affects the effect of calcium-magnesium separation. Commonly used carbonization equipment mainly includes bubbling carbonization tower, intermittent stirring carbonization tower, spray carbonization tower and supergravity carbonization device. However, experiments have found that bubbling carbonization, spray carbonization and supergravity bed carbonization are not ideal for separating calcium and magnesium. The magnesium oxide content in calcium carbonate is more than 10%. When using an intermittent stirring carbonization tower, it must be carried out under pressure and stirring, and the separation effect can only be achieved after multiple carbonizations. It has the disadvantages of high production cost, large area of ​​carbonization tower, and difficulty in control. In addition, the particle size of the separated calcium carbonate product is generally 2 to 10 μm, which does not reach the nanometer level, and the product market price is low. Summary of the invention

[0004] The present application provides a method and system for separating calcined dolomite to solve the following technical problem: how to improve the calcium and magnesium separation effect of calcined dolomite.

[0005] In a first aspect, the present application provides a method for separating calcined dolomite, the method comprising:

[0006] The dolomite is subjected to a digestion treatment to obtain a first emulsion;

[0007] The carbon dioxide mixed gas with a set pressure is ejected by using a jet method to form a high-speed carbon dioxide mixed gas jet;

[0008] Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion is inhaled and the carbon dioxide mixed gas with a set pressure is subjected to a first carbonization reaction to obtain a second emulsion.

[0009] Optionally, the set pressure is 0.5 MPa to 0.8 MPa.

[0010] Optionally, the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 30% to 35%.

[0011] Optionally, the temperature of the first carbonization reaction is 10°C to 30°C.

[0012] Optionally, the volume ratio of the carbon dioxide mixed gas with a set pressure to the first emulsion is (110-150) Nm 3 :1m 3 .

[0013] Optionally, a digestion agent is used for the digestion treatment, and the weight ratio of the dolomite to the digestion agent is 1:(30-35).

[0014] Optionally, the method further includes:

[0015] The second emulsion is subjected to a buffering treatment so as to allow the second emulsion to undergo a second carbonization reaction to obtain a target emulsion.

[0016] Optionally, the buffering treatment time is 1 h to 2 h.

[0017] In a second aspect, the present application provides a system for separating dolomite from calcined dolomite, the system being used to implement the method described in any one of the first aspects, the system comprising:

[0018] Milk making tank 1, used for digestion of calcined dolomite;

[0019] The carbonization reaction part 2 is connected to the emulsion making tank 1 and is used for the first emulsion to undergo a first carbonization reaction with a carbon dioxide mixed gas having a set pressure. The carbonization reaction part 2 includes an injector 21 .

[0020] Optionally, the carbonization reaction unit 2 further includes a buffer tank 22, which is connected to the injector 21 and is used for buffering the second emulsion.

[0021] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0022] The method for separating calcined dolomite provided in the embodiment of the present application comprises: digesting the calcined dolomite to obtain a first emulsion; using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; under the action of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion is inhaled and the carbon dioxide mixed gas with a set pressure is subjected to a first carbonization reaction to obtain a second emulsion. The calcined dolomite is digested to obtain a first emulsion containing calcium hydroxide and magnesium hydroxide; using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet, and negative pressure is generated around the high-speed carbon dioxide mixed gas jet, and under the action of the negative pressure, the first emulsion and the carbon dioxide mixed gas are driven to mix and collide quickly, thereby achieving the purpose of efficient carbonization and fully improving the calcium-magnesium separation effect of the calcined dolomite. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0025] Figure 1 A schematic flow chart of a method for separating calcined dolomite provided in an embodiment of the present application;

[0026] Figure 2 A schematic diagram of the system structure of dolomite calcining separation provided in an embodiment of the present application; wherein, 1-milk making tank, 2-carbonization reaction unit, 21-ejector, 22-buffer tank, 3-compressor, 4-gas storage tank, 5-delivery pump, 6-pressure pump, 7-filter;

[0027] Figure 3 A schematic diagram of the structure of an ejector provided in an embodiment of the present application; wherein 211 is a nozzle, 212 is an inlet area, 213 is a mixing area, and 214 is a diffusion area;

[0028] Figure 4 A schematic diagram of the system structure of dolomite calcining separation provided in the embodiment of the present application (two-stage carbonization); wherein,

[0029] 1-milk making tank, 2-carbonization reaction unit, 21-1-first-stage ejector, 22-1-first-stage buffer tank, 5-1-first-stage delivery pump, 2-1-first-stage carbonization reaction unit, 21-2-second-stage ejector, 22-2-second-stage buffer tank, 3-compressor, 4-gas storage tank, 5-2-second-stage delivery pump, 2-2-second-stage carbonization reaction unit, 6-pressure pump, 7-filter. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0031] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0032] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In the proportional relationship involved in this article, the parameters that need to be described by the ratio should be understood as the antecedent of the proportional formula in the order of description, and the proportional numbers are understood as the latter of the proportional formula. For example, the mass ratio of substance A, substance B and substance C is 1:2:3, then substance A, substance B and substance C should correspond to the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0033] In this document, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation. In addition, in addition to being used to indicate an orientation or positional relationship, some of the above terms may also be used to indicate other meanings. For example, the term "upper" may also be used to indicate a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in the present invention can be understood according to the specific circumstances. In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0034] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0035] In a first aspect, the present application provides a method for separating calcined dolomite. Figure 1 A schematic diagram of a method for separating dolomite calcined white provided in the embodiment of the present application; see Figure 1 , the method comprising:

[0036] S1, digesting the calcined dolomite to obtain a first emulsion;

[0037] In some embodiments, the digestion treatment is carried out using a digestant, and the weight ratio of the dolomite to the digestant is 1:(30-35).

[0038] In the embodiment of the present application, the main components of dolomite are calcium carbonate and magnesium carbonate, which can be used as raw materials for smelting magnesium metal and extracting magnesium oxide. Dolomite is calcined at high temperature to obtain dolomite calcined white, and the main components of the dolomite calcined white include CaO·MgO. The digestion treatment of dolomite calcined white can be to use a digestant to digest the dolomite calcined white, and the weight ratio of dolomite calcined white to the digestant can be 1: (30-35), so as to ensure the full reaction of dolomite calcined white and the digestant, which is conducive to the smooth progress of the subsequent carbonization reaction. Exemplarily, the weight ratio of dolomite calcined white to the digestant can be 1:30, 1:31, 1:32, 1:33, 1:34, 1:35, etc. Generally speaking, the digestant can be water, and the CaO·MgO in the dolomite calcined white reacts chemically with H2O, that is, CaO·MgO+H2O=Ca(OH)2+Mg(OH)2.

[0039] S2. using a jet method to eject the carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet;

[0040] In some embodiments, the set pressure is 0.5 MPa to 0.8 MPa.

[0041] In the embodiment of the present application, the injection method is a method that utilizes the injection effect of a high-speed fluid to achieve a specific process purpose. The injection method is mainly based on the conservation of momentum and the Bernoulli principle in fluid mechanics. A high-speed jet is formed by ejecting a working fluid (usually a gas or liquid) with a high pressure and speed at high speed. According to the Bernoulli principle, a low-pressure area will be generated around a high-speed flowing fluid, thereby generating a suction effect, which can inhale other fluids or substances. At the same time, the high-speed jet mixes and collides with the inhaled fluid to achieve energy transfer and momentum exchange, thereby achieving a specific process effect. The set pressure can be 0.5MPa to 0.8MPa, and the carbon dioxide mixed gas with the set pressure can be ejected using the injection method to form a high-speed carbon dioxide mixed gas jet, and a negative pressure is generated around the high-speed carbon dioxide mixed gas jet. Under the action of the negative pressure, the first emulsion and the carbon dioxide mixed gas are driven to mix and collide rapidly, thereby achieving the purpose of efficient carbonization and fully improving the calcium-magnesium separation effect of dolomite calcined white. Specific chemical reactions include:

[0042] Ca(OH)2+CO2=CaCO3+H2O

[0043] Mg(OH)2+CO2=MgCO3+H2O

[0044] MgCO3+H2O+CO2=Mg(HCO3)2

[0045] If the set pressure is higher than 0.8 MPa, the cost of compressed gas may increase, and the negative pressure formed in the injection method may be large, and too much first emulsion may be sucked in. A large amount of the first emulsion may not have time to undergo carbonization reaction, resulting in poor carbonization effect; if the set pressure is lower than 0.5 MPa, the negative pressure formed in the injection method is small, the amount of sucked emulsion is small, the carbonization efficiency is low, resulting in low carbon dioxide utilization rate and increased cost. Exemplarily, the set pressure can be 0.5 MPa, 0.6 MPa, 0.7 MPa, 0.8 MPa, etc.

[0046] In some embodiments, the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 30% to 35%.

[0047] In the embodiment of the present application, the mass fraction of carbon dioxide in the carbon dioxide mixed gas can be 30% to 35%. During the mixing and collision of the carbon dioxide mixed gas and the first emulsion, the carbonization reaction can be fully achieved, thereby achieving an ideal calcium-magnesium separation effect. If the mass fraction of carbon dioxide in the carbon dioxide mixed gas is higher than 35%, a wrapping phenomenon may occur during the carbonization reaction, that is, MgCO3 has not had time to react to generate Mg(HCO3)2, and is wrapped by the rapidly generated CaCO3, which is difficult to further carbonize and causes a high magnesium content in calcium; if the mass fraction of carbon dioxide in the carbon dioxide mixed gas is lower than 30%, it may cause the time required for carbonization to be extended, resulting in a carbonization reaction that is too late to occur or insufficient carbonization reaction, and an increase in production costs. Exemplarily, the mass fraction of carbon dioxide in the carbon dioxide mixed gas can be 30%, 31%, 32%, 33%, 34%, 35%, etc. In addition, the remaining gas in the carbon dioxide mixed gas can be air.

[0048] S3, under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion is inhaled and the carbon dioxide mixed gas with a set pressure is subjected to a first carbonization reaction to obtain a second emulsion.

[0049] In some embodiments, the temperature of the first carbonization reaction is 10°C to 30°C.

[0050] In the embodiment of the present application, the temperature of the carbonization reaction can be 10°C to 30°C. At a certain temperature, Mg(HCO3)2 has a certain saturation in water. Considering the exothermic reaction of carbonization, the ideal calcium-magnesium separation effect is achieved in the temperature range of 10°C to 30°C; if the temperature of the carbonization reaction is higher than 30°C, the saturation of Mg(HCO3)2 in the emulsion is reduced. After the carbonization reaction reaches a certain degree, the dissolution of Mg(HCO3)2 in the emulsion is close to saturation, which will inhibit the remaining MgCO3 in the emulsion from further carbonization reaction to generate Mg(HCO3)2, resulting in poor calcium-magnesium separation effect; if the temperature of the carbonization reaction is lower than 10°C, the first emulsion needs to be forced to cool during production, resulting in high carbonization production costs. Exemplarily, the temperature of the carbonization reaction can be 10°C, 15°C, 20°C, 25°C, 30°C, etc. In addition, the time of the first carbonization reaction can be 20s to 30s.

[0051] In some embodiments, the volume ratio of the carbon dioxide mixed gas with a set pressure to the first emulsion is (110-150) Nm 3 :1m 3 .

[0052] In the embodiment of the present application, the volume ratio of the carbon dioxide mixed gas with a set pressure to the first emulsion can be (110-150) Nm 3 :1m 3 , so that the carbon dioxide mixed gas with the set pressure can fully react with the first emulsion to achieve the ideal calcium-magnesium separation effect. Exemplarily, the volume ratio of the carbon dioxide mixed gas with the set pressure to the first emulsion can be 110Nm 3 :1m 3 , 115Nm 3 :1m 3 , 120Nm 3 :1m 3 、125Nm 3 :1m 3 、130Nm 3 :1m 3 、135Nm 3 :1m 3 、140Nm 3 :1m 3 、145Nm 3 :1m 3 、150Nm 3 :1m 3 wait.

[0053] In some embodiments, the method further comprises:

[0054] S4, subjecting the second emulsion to a buffer treatment so as to allow the second emulsion to undergo a second carbonization reaction to obtain a target emulsion.

[0055] In some embodiments, the buffer treatment time is 1 h to 2 h.

[0056] In an embodiment of the present application, the second emulsion is buffered to provide reaction time and space for the materials in the second emulsion that have not had time to carbonize, thereby realizing the second carbonization reaction, and at the same time, the excess gas escapes, further improving the calcium-magnesium separation effect. The buffering time can be 1h to 2h, so that the second carbonization reaction is fully carried out. Exemplarily, the buffering time can be 1h, 1.2h, 1.4h, 1.6h, 1.8h, 2h, etc. After the above-mentioned first carbonization reaction and the first carbonization reaction, the target emulsion can be separated into solid and liquid, and the filter cake calcium carbonate (wt%) ≥ 97.04; magnesium ions in the filtrate (g / L) ≥ 6.15 can be achieved. In order to further improve the calcium-magnesium separation effect, the first carbonization reaction and the second carbonization reaction can be repeated many times.

[0057] In summary, the method for separating dolomite from calcined dolomite provided in the embodiments of the present application has the following advantages:

[0058] 1. The first carbonization reaction: A high-speed carbon dioxide mixed gas jet is formed by the injection method, and negative pressure is used to drive the first emulsion and the carbon dioxide mixed gas to mix and collide quickly to achieve efficient carbonization; the injection method can produce a high-speed jet, which enhances the power of the reaction and increases the reaction rate; the negative pressure promotes the full contact of the two reactants, ensures the efficient carbonization reaction, and fully improves the calcium and magnesium separation effect of dolomite calcined white.

[0059] 2. Second carbonization reaction: The second emulsion is buffered to encourage the incompletely reacted materials to continue the carbonization reaction, while allowing excess gas to escape, providing some materials that have not had time to fully react in the first carbonization reaction with an opportunity for further reaction, thereby increasing the conversion rate of the reaction. The overflow of excess gas helps to improve the purity of the target emulsion and further enhance the calcium-magnesium separation effect.

[0060] In a second aspect, the present application provides a system for separating dolomite from calcined dolomite, wherein the system is used to implement the method described in any one of the first aspects. Figure 2 A schematic diagram of the system structure of dolomite calcined white separation provided in the embodiment of the present application; see Figure 2 , the system comprising:

[0061] Milk making tank 1, used for digestion of calcined dolomite;

[0062] The carbonization reaction part 2 is connected to the emulsion making tank 1 and is used for the first emulsion to undergo a first carbonization reaction with a carbon dioxide mixed gas having a set pressure. The carbonization reaction part 2 includes an injector 21 .

[0063] In an embodiment of the present application, the emulsion making tank 1 is used for digestion treatment of calcined dolomite to obtain a first emulsion; the carbonization reaction unit 2 is used for a first carbonization reaction of the first emulsion with a carbon dioxide mixed gas with a set pressure to obtain a second emulsion, and the carbonization reaction unit 2 includes an injector 21. Figure 3 A schematic diagram of the structure of an ejector provided in an embodiment of the present application; see Figure 3 The ejector 21 includes a nozzle 211, an inhalation zone 212, a mixing zone 213 and a diffusion zone 214, wherein the inhalation zone 212 accommodates the nozzle 211. In the ejector, the nozzle 211 ejects a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; the first emulsion is inhaled under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet in the inhalation zone 212, and mixed and collided with the carbon dioxide mixed gas with a set pressure in the mixing zone 213 to perform a first carbonization reaction (the carbon dioxide in the mixed gas contacts and reacts with Ca(OH)2 and Mg(OH)2 in the emulsion to produce CaCO3 and MgCO3 respectively, and MgCO3 contacts and reacts with CO2 again to produce Mg(HCO3)2), and the reaction materials are mixed and collided more intensely and frequently in the diffusion zone 214, and the carbonization reaction is further promoted because the diffusion temperature of the materials passing through the mixing zone 213 is reduced.

[0064] In some embodiments, the carbonization reaction unit 2 further includes a buffer tank 22, which is connected to the injector 21 and is used for buffering the second emulsion.

[0065] In the embodiment of the present application, in order to ensure the reaction degree of the reaction materials, a buffer tank 22 is set to extend the carbonization reaction time, so that the materials of the second emulsion that have not had time to carbonize in the buffer tank 22 have reaction time and space, and the excess gas escapes, further improving the separation effect of calcined white calcium magnesium. In addition, a stirrer can also be set inside the buffer tank 22.

[0066] Exemplarily, the system for separating dolomite from calcined white also includes: a compressor 3, a gas storage tank 4, a delivery pump 5, a pressure pump 6 and a filter 7. Among them, the inlet end of the gas storage tank 4 is connected to the compressor 3, and the outlet end is connected to the air inlet of the ejector 21. The carbon dioxide mixed gas passes through the compressor 3 and is compressed to 0.5-0.8 MPa of compressed gas, which is temporarily stored in the gas storage tank 4; the outlet of the gas storage tank 4 is connected to the ejector 21. The outlet of the milking tank 1 is connected to the feed port of the delivery pump 5; the calcined white dolomite and water are added to the milking tank 1, stirred to make milk and refined to obtain the first emulsion. The ejector 21 has two feed ports, which are connected to the gas storage tank 4 and the delivery pump 5 respectively. The outlet of the ejector 21 is connected to the buffer tank 22. The compressed mixed gas in the gas storage tank 4 passes through the nozzle 211 of the ejector 21, and forms a negative pressure in the suction area 212 of the ejector 21. At the same time, the first emulsion prepared in the emulsion tank 1 enters the ejector 21 through the delivery pump 5. Under the action of the negative pressure, the mixed gas and the first emulsion are mixed and collided in the mixing area 213 to undergo a carbonization reaction. In the diffusion area 214, the temperature of the two decreases and further collides and carbonizes. The reacted material (the second emulsion) enters the buffer tank 22 for further carbonization reaction and releases excess gas. The inlet of the pressure pump 6 is connected to the buffer tank 22, and the outlet is connected to the filter 7. The reacted material (target emulsion) in the buffer tank 22 is transported to the filter 7 by the pressure pump 6, and the solid-liquid separation of the target emulsion is achieved by the filter 7, thereby separating calcium and magnesium. Calcium is solid in the form of calcium carbonate and is insoluble in water; magnesium is in the form of magnesium bicarbonate and is easily soluble in water.

[0067] As an implementation method in the embodiment of the present application, the above-mentioned carbonization reaction unit 2 can be set in multiple, and a single carbonization reaction unit 2 can include a delivery pump 5, an ejector 21 and a buffer tank 22. The three are used in series to form a primary carbonization reaction unit. A secondary or multi-stage carbonization of the emulsion can also be set to further improve the calcium-magnesium separation effect and further reduce the magnesium content in calcium carbonate, with obvious benefits. Figure 4 A schematic diagram of the system structure of dolomite calcining separation provided in the embodiment of the present application (two-stage carbonization); see Figure 4 The first-stage ejector 21-1, the first-stage buffer tank 22-1 and the first-stage delivery pump 5-1 constitute the first-stage carbonization reaction section 2-1, and the first-stage ejector 21-2, the first-stage buffer tank 22-2 and the first-stage delivery pump 5-2 constitute the second-stage carbonization reaction section 2-2, thereby realizing the second-stage carbonization of the emulsion.

[0068] The system for separating calcined dolomite from calcined white is realized based on the above-mentioned method for separating calcined dolomite. The specific steps of the method for separating calcined dolomite from calcined white can refer to the above-mentioned embodiment. Since the system for separating calcined dolomite from calcined white adopts part or all of the technical solutions of the above-mentioned embodiment, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiment, which will not be described one by one here.

[0069] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for the unrecorded specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, then carry out according to general international standards, normal conditions or according to the conditions recommended by the manufacturer.

[0070] Example 1

[0071] A method for separating calcined dolomite, comprising:

[0072] Using water to digest the calcined dolomite to obtain a first emulsion; wherein the weight ratio of the calcined dolomite to water is 1:30;

[0073] Using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; wherein the set pressure is 0.5 MPa, and the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 30%;

[0074] Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion and the carbon dioxide mixed gas with a set pressure are inhaled to perform a first carbonization reaction to obtain a second emulsion; wherein the temperature of the first carbonization reaction is 20°C, the time of the first carbonization reaction is 30s; the volume ratio of the carbon dioxide mixed gas to the first emulsion is 150Nm 3 :1m 3 ;

[0075] The second emulsion is subjected to a buffer treatment so as to undergo a second carbonization reaction to obtain a target emulsion; wherein the buffer treatment time is 2 hours.

[0076] Example 2

[0077] A method for separating calcined dolomite, comprising:

[0078] Using water to digest the calcined dolomite to obtain a first emulsion; wherein the weight ratio of the calcined dolomite to water is 1:30;

[0079] Using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; wherein the set pressure is 0.5 MPa, and the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 34%;

[0080] Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion and the carbon dioxide mixed gas with a set pressure are inhaled to perform a first carbonization reaction to obtain a second emulsion; wherein the temperature of the first carbonization reaction is 30°C, the time of the first carbonization reaction is 30s; the volume ratio of the carbon dioxide mixed gas to the first emulsion is 130Nm 3 :1m 3 ;

[0081] The second emulsion is subjected to a buffer treatment so as to undergo a second carbonization reaction to obtain a target emulsion; wherein the buffer treatment time is 1.5 hours.

[0082] Example 3

[0083] A method for separating calcined dolomite, comprising:

[0084] Using water to digest the calcined dolomite to obtain a first emulsion; wherein the weight ratio of the calcined dolomite to water is 1:35;

[0085] Using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; wherein the set pressure is 0.5 MPa, and the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 32%;

[0086] Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion and the carbon dioxide mixed gas with a set pressure are inhaled to perform a first carbonization reaction to obtain a second emulsion; wherein the temperature of the first carbonization reaction is 24°C, the time of the first carbonization reaction is 30s; the volume ratio of the carbon dioxide mixed gas to the first emulsion is 120Nm 3 :1m 3 ;

[0087] The second emulsion is subjected to a buffer treatment so as to undergo a second carbonization reaction to obtain a target emulsion; wherein the buffer treatment time is 1 hour.

[0088] Example 4

[0089] A method for separating calcined dolomite, comprising:

[0090] Using water to digest the calcined dolomite to obtain a first emulsion; wherein the weight ratio of the calcined dolomite to water is 1:30;

[0091] Using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; wherein the set pressure is 0.8 MPa, and the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 30%;

[0092] Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion and the carbon dioxide mixed gas with a set pressure are inhaled to perform a first carbonization reaction to obtain a second emulsion; wherein the temperature of the first carbonization reaction is 28°C, the time of the first carbonization reaction is 20s; the volume ratio of the carbon dioxide mixed gas to the first emulsion is 150Nm 3 :1m 3 ;

[0093] The second emulsion is subjected to a buffer treatment so as to undergo a second carbonization reaction to obtain a target emulsion; wherein the buffer treatment time is 2 hours.

[0094] Example 5

[0095] A method for separating calcined dolomite, comprising:

[0096] Using water to digest the calcined dolomite to obtain a first emulsion; wherein the weight ratio of the calcined dolomite to water is 1:35;

[0097] Using a jet method to eject a carbon dioxide mixed gas with a set pressure to form a high-speed carbon dioxide mixed gas jet; wherein the set pressure is 0.8 MPa, and the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 35%;

[0098] Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion and the carbon dioxide mixed gas with a set pressure are inhaled to perform a first carbonization reaction to obtain a second emulsion; wherein the temperature of the first carbonization reaction is 22°C, the time of the first carbonization reaction is 20s; the volume ratio of the carbon dioxide mixed gas to the first emulsion is 110Nm 3 :1m 3 ;

[0099] The second emulsion is subjected to a buffer treatment so as to undergo a second carbonization reaction to obtain a target emulsion; wherein the buffer treatment time is 1 hour.

[0100] Comparative Example 1

[0101] Based on the disclosure of Example 1, the difference between Comparative Example 1 and Example 1 is that the pressure is set to 0.9 MPa.

[0102] Comparative Example 2

[0103] Based on the disclosure of Example 1, Comparative Example 2 is different from Example 1 in that the mass fraction of carbon dioxide in the carbon dioxide mixed gas is 60%.

[0104] For the final target emulsion in the method for separating dolomite calcined white provided in Examples 1 to 5 and Comparative Examples 1 to 2, solid-liquid separation was performed, and the filter cake and filtrate were analyzed. Please refer to the analysis results of the filter cake and filtrate shown in Table 1.

[0105] Table 1 Analysis results of filter cake and filtrate

[0106] Serial number Filter cake calcium carbonate (wt%) <![CDATA[Filter liquor Mg 2+ (g / L)]]> Example 1 98.33 7.22 Example 2 97.04 6.96 Example 3 98.52 6.18 Example 4 97.93 7.14 Example 5 98.37 6.15 Comparative Example 1 91.33 5.72 Comparative Example 2 89.38 5.26

[0107] As shown in Table 1, the quality of calcium carbonate obtained in Examples 1 to 5 and the Mg content of the filtrate 2+ The quality of calcium carbonate and filtrate obtained in Comparative Examples 1 to 2 is higher than that in Comparative Examples 1 to 2, indicating that the method for separating calcined dolomite provided in the embodiments of the present application can achieve better calcium and magnesium separation effects.

[0108] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0109] (1) In view of the characteristics of calcium and magnesium separation and carbonization, a negative pressure is formed under the condition of blowing compressed carbon dioxide gas by using the injection method. The negative pressure drives the calcined white emulsion and the carbon dioxide mixed gas to mix and collide quickly, thereby achieving the purpose of carbonization;

[0110] (2) Buffering treatment further prolongs the carbonization time; at the same time, in order to improve the quality and purity of calcium and magnesium, a two-stage or multi-stage carbonization series method can be used to separate calcium and magnesium more thoroughly;

[0111] (3) The mixed gas of CaO and MgO in the calcined dolomite is subjected to carbonization reaction after emulsification and compression through an ejector, and calcium carbonate and magnesium bicarbonate solution are obtained after solid-liquid separation, thereby achieving an ideal separation effect without the need for other additional treatments, realizing the green and environmentally friendly separation of calcium and magnesium in the calcined dolomite, and improving the value of the product; and the method is simple, low-cost, and easy to promote;

[0112] (4) The method of separating dolomite from calcined dolomite can not only realize calcium and magnesium carbide better, but also realize continuous and automated production, while improving the carbonization quality and efficiency, reducing production investment, floor space, etc.

[0113] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A method for separating calcined dolomite, characterized in that: The method comprises: The dolomite is subjected to a digestion treatment to obtain a first emulsion; The carbon dioxide mixed gas with a set pressure is ejected by using a jet method to form a high-speed carbon dioxide mixed gas jet; Under the effect of negative pressure generated around the high-speed carbon dioxide mixed gas jet, the first emulsion is inhaled and the carbon dioxide mixed gas with a set pressure is subjected to a first carbonization reaction to obtain a second emulsion.

2. The method according to claim 1, characterized in that The set pressure is 0.5MPa to 0.8MPa.

3. The method according to claim 1 or 2, characterized in that: The mass fraction of carbon dioxide in the carbon dioxide mixed gas is 30% to 35%.

4. The method according to claim 1, characterized in that: The temperature of the first carbonization reaction is 10°C to 30°C.

5. The method according to claim 1, characterized in that The volume ratio of the carbon dioxide mixed gas with a set pressure to the first emulsion is (110-150) Nm 3 :1m 3 .

6. The method according to claim 1, characterized in that The digestion treatment is carried out using a digestion agent, and the weight ratio of the dolomite to the digestion agent is 1:(30-35).

7. The method according to claim 1, characterized in that The method further comprises: The second emulsion is subjected to a buffering treatment so as to allow the second emulsion to undergo a second carbonization reaction to obtain a target emulsion.

8. The method according to claim 7, characterized in that The buffer treatment time is 1 h to 2 h.

9. A system for separating dolomite from calcined dolomite, characterized in that: The system is used to implement the method described in any one of claims 1 to 8, and the system includes: A milk making tank (1) is used for digestion of calcined dolomite; The carbonization reaction section (2) is connected to the emulsion making tank (1) and is used for performing a first carbonization reaction between the first emulsion and a carbon dioxide mixed gas with a set pressure. The carbonization reaction section (2) includes an ejector (21).

10. The system according to claim 9, characterized in that The carbonization reaction section (2) further comprises a buffer tank (22) which is in communication with the injector (21) and is used for buffering the second emulsion.

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