Opposed even nozzle composite carbonization device and method for producing nanometer calcium carbonate

Abstract

The application discloses an opposed even-nozzle composite carbonization device for producing nano calcium carbonate, which comprises a pre-carbonization kettle body; a cleaning nozzle is arranged at the top end of the pre-carbonization kettle body, and a seed outlet is arranged at the bottom end of the pre-carbonization kettle; a carbonization agent nozzle and a calcium source nozzle are arranged in the pre-carbonization kettle, and the carbonization agent nozzle and the calcium source nozzle are centrally symmetrical to the center of the pre-carbonization kettle body. The unique structure of the pre-carbonization kettle is that a pair of nozzles which are in the same plane, coaxial, opposite and symmetrical, or two pairs of nozzles which are in the same plane, coaxial, opposite and symmetrical respectively are formed, each pair of nozzles sprays the same amount of carbonization agent and calcium source, and a stirring device is not arranged. The pre-carbonization reaction is greatly intensified by the spray impact, a large number of crystal nuclei can be formed instantaneously, the product particle size can be effectively controlled, the product quality and the production efficiency are improved, the energy consumption is obviously reduced without the stirring device, and the utilization rate of carbon dioxide is obviously improved by adopting a three-stage continuous carbonization process.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of chemical production, in particular to a device and method for producing nano calcium carbonate by using a compound carbonization device with an even number of opposed nozzles. BACKGROUND

[0002] Calcium carbide is an important bulk chemical product. According to statistics, the total production of calcium carbide in China in 2021 was 28.25 million tons. When calcium carbide is used to produce acetylene and downstream chemical products such as PVC, vinylon, lime nitrogen, dicyandiamide, chlorobutyl rubber, carbon black, polyvinyl chloride, polyvinyl alcohol, etc., a large amount of calcium carbide waste residue will be discharged. 1 ton of calcium carbide reacts with water to produce about 6 tons of wet calcium carbide slurry, which is equivalent to about 1.2 tons of dry calcium carbide residue. In 2021, the total amount of dry calcium carbide residue produced nationwide was as high as 33.9 million tons. The main components of calcium carbide residue are: calcium hydroxide content of 85-90%, which is a highly alkaline substance with a pH value of 12.5, and also contains silicon oxide, aluminum oxide, a small amount of calcium carbonate, iron trioxide, magnesium oxide, titanium dioxide, carbon residue, calcium sulfide and other impurities. The calcium carbide residue slurry has a high water content, high alkalinity and large flow, and is a key pollution source of the sewage pipe network, so the calcium carbide residue problem has become a major bottleneck affecting the expansion and production development of calcium carbide downstream product manufacturers such as PVC. How to comprehensively recycle calcium carbide residue and turn waste into treasure is an urgent task for many enterprises.

[0003] The comprehensive utilization of calcium carbide residue has no mature, sustainable, low-cost and high-value resource treatment method at home and abroad. The main application fields are as follows: first, it is used as building materials and roadbed materials, which is a simple utilization of calcium carbide residue, and requires a near principle, otherwise the transportation cost is too high, and it is difficult to stably consume and utilize calcium carbide residue for a long time; second, it is applied to the treatment of acid wastewater and acid waste gas, such as a large amount of acid wastewater in the metallurgical industry, sulfur-containing waste gas in sulfuric acid plants and thermal power plants, fluoride-containing hydrogen chloride or hydrogen chloride waste gas in phosphate fertilizer industry and chlor-alkali industry, etc. This also requires a near principle, and it is better to use pipeline or belt conveying, but this method will produce new calcium salt waste residue, causing new environmental problems; third, it is used to produce cement, which requires dry calcium carbide residue, because the water content of wet calcium carbide residue is too high to be suitable for cement production; at the same time, cement production in the major calcium carbide production areas in the northwest of China is greatly affected by seasons, and usually cannot be produced in winter due to the suspension of the construction industry; fourth, it is used to replace calcium hydroxide to produce some ordinary chemical products, such as calcium oxide, bleaching powder, light calcium carbonate, potassium chlorate, epoxy chloropropane, etc. Due to the high content of harmful impurities in calcium carbide residue, the production process of replacing calcium hydroxide will cause continuous accumulation of harmful impurities, making this replacement unsustainable and affecting product quality. Many research institutions are now studying high-value utilization methods of calcium carbide residue, and the most important research direction is to use calcium carbide residue to produce nano calcium carbonate, but most of them are still in the experimental research and pilot stage, and no industrialization reports have been seen.

[0004] In the process of producing nano calcium carbonate with carbide slag as raw material, first, the carbide slag is leached with ammonium chloride or ammonium nitrate solution as leaching agent, then filtered and washed to obtain calcium chloride (calcium nitrate)-ammonia solution; finally, carbonation reaction is carried out with carbon dioxide to obtain light calcium carbonate. The calcium chloride (calcium nitrate)-ammonia system is completely different from the lime milk system, and the carbonation process and mechanism of the two in producing light calcium carbonate are also completely different.

[0005] In the process of carbonation reaction for producing calcium carbonate with the ammonia solution of calcium chloride (calcium nitrate) as calcium source and carbon dioxide as carbonation agent, if no dispersant and modifier is added, it is found that the particle size of the produced calcium carbonate is obviously larger than the average particle size of the light calcium carbonate produced by the traditional method, and the agglomeration phenomenon is very serious, the D 50 value is up to 27.61 μm, not to mention for producing nano calcium carbonate. It is proved that, compared with the simple CO2 carbonation process, the calcium chloride (calcium nitrate)-ammonia system has long time, slow speed, coarse particles and serious agglomeration. The root cause lies in that, although the calcium ion concentration in the calcium chloride (calcium nitrate)-ammonia system is very large, the solution pH value is low, the CO2 absorption reaction speed is slow, and a large number of calcium carbonate crystal nuclei cannot be formed in the initial stage of carbonation, thus being not conducive to the ultra-fining of the particles.

[0006] Although the new concept of composite carbonation is proposed in the prior art, the whole carbonation process is carried out in two steps. In the first stage, a proper amount of ammonium bicarbonate is added in the calcium chloride (calcium nitrate)-ammonia system to carry out composite reaction, a large amount of calcium bicarbonate is formed, and further converted into calcium carbonate crystal nuclei, so as to realize the ultra-fining of the calcium carbonate particles. In the second stage, carbon dioxide is introduced to carry out carbonation reaction, and finally sub-nano calcium carbonate with an average particle size of 340 nm is obtained, which is still not the nano calcium carbonate in the strict sense of less than 100 nm. It can be seen that the actual effect of the composite carbonation described in the literature is still not satisfactory.

[0007] The Chinese invention with publication number CN102531017A discloses a carbonator and method for producing nano calcium carbonate. The scheme adopts two-time carbonation pipe reaction to prepare nano calcium carbonate. Although the method can prepare nano calcium carbonate with uniform particle size, it still cannot stably control the particle size of the product.

[0008] The Chinese invention with publication number CN104891545A discloses a carbonation reaction device and method for producing nano calcium carbonate. The scheme adopts a carbonation tower to carry out two-time carbonation. Although the device solves the problems of dispersibility and oil absorption value of the nano calcium carbonate, the quality of the nano calcium carbonate prepared by the scheme still cannot meet the requirements, and the particle size of the nano calcium carbonate cannot be controlled.

[0009] The patent with the application number 20182004325.1 discloses a nano calcium carbonate production reactor for neutral transparent silicone glue, which uses neutral transparent silicone glue for the production of nano calcium carbonate. Since an emulsifier is used, the power consumption is high, and it is not suitable for the production of low-cost nano calcium carbonate.

[0010] The utility model patent with the patent number CN 209866034U discloses a carbonization kettle for nano calcium carbonate production, which increases the gas-liquid mixing contact area through high-speed propeller stirring. However, the device is not suitable for the production of nano calcium carbonate from liquid raw materials, and still has the problem of high energy consumption.

[0011] Therefore, it is an urgent technical problem for those skilled in the art to provide a device and method for producing nano calcium carbonate by opposing even nozzle composite carbonization, which can control the particle size of the product, improve the product quality, and improve the production efficiency. SUMMARY

[0012] The present application aims to at least partially solve one of the above technical problems in the prior art.

[0013] To this end, one object of the present application is to provide a device for producing nano calcium carbonate by opposing even nozzle composite carbonization, comprising a pre-carbonization kettle body;

[0014] Preferably, the top end of the pre-carbonization kettle body is provided with a cleaning nozzle, and the bottom end of the pre-carbonization kettle is provided with a seed outlet.

[0015] The pre-carbonization kettle is internally provided with carbonization agent nozzles and calcium source nozzles, and the carbonization agent nozzles and calcium source nozzles are centrally symmetric with the center inside the pre-carbonization kettle body.

[0016] Preferably, the cleaning nozzle is provided with a plurality of cleaning nozzles.

[0017] Preferably, the carbonization agent nozzles and the calcium source nozzles are provided with a plurality of carbonization agent nozzles and a plurality of calcium source nozzles, and the number of carbonization agent nozzles and calcium source nozzles is the same.

[0018] The present application also provides a method for producing nano calcium carbonate by opposing even nozzle composite carbonization, comprising the following steps:

[0019] (1) Dry calcium carbide slag or wet calcium carbide slag after pressure filtration is added as a calcium source to a sealed leaching tank containing a leaching agent, the amount of leaching agent is 105-110% of the amount of substance of calcium hydroxide in calcium carbide slag, and the leaching reaction is carried out under the condition of electric stirring, and a clear and transparent calcium source solution without solid impurities is obtained after filtration;

[0020] (2) Dissolve the soluble carbonate in water to prepare a carbonization agent;

[0021] (3) the amount of calcium ions in the calcium source solution is calculated, and the amount of carbonate material in the carbonizing agent is equal to the amount of calcium ions; then the above device is used to spray the calcium source solution through the calcium source nozzle and the carbonizing agent through the carbonizing agent nozzle into the pre-carbonization kettle body, and the calcium source solution and the carbonizing agent complete the pre-carbonization reaction in an instant through the impact of the opposite spraying, forming a calcium carbonate seed slurry;

[0022] (4) immediately after the pre-carbonization reaction is completed, the calcium carbonate seed slurry is discharged, and then the cleaning nozzle at the top of the pre-carbonization kettle is opened to spray clean water for washing, and the cleaning liquid is mixed into the seed slurry;

[0023] (5) a three-stage continuous bubbling carbonization kettle is used:

[0024] 1) the calcium carbonate seed slurry is poured into the first-stage carbonization kettle, calcium source solution is added again, carbon dioxide is introduced, and the stirring device in the first-stage carbonization kettle is turned on, and at the same time, the calcium ion concentration and pH value detection instrument are turned on, when the calcium ion concentration in the first-stage carbonization kettle reaction is reduced to less than one third of the inlet concentration, the first-stage carbonization slurry is discharged and sent to the first-stage slurry tank;

[0025] 2) the carbonization slurry in the first-stage slurry tank is sent to the second-stage carbonization kettle, and at the same time, the carbon dioxide from the top of the first-stage carbonization kettle is sent to the bottom of the second-stage carbonization kettle for carbonization reaction again, when the calcium ion concentration in the second-stage carbonization kettle is reduced to less than one third of the inlet concentration, the slurry from the second-stage carbonization kettle is discharged and temporarily stored in the second-stage slurry tank;

[0026] 3) the slurry in the second-stage slurry tank is transferred to the third-stage carbonization kettle, and at the same time, the carbon dioxide from the top of the second-stage carbonization kettle is sent to the bottom of the third-stage carbonization kettle for carbonization reaction again, and ammonia water is added before the reaction to ensure that the calcium ions can react completely, until the calcium ion concentration is reduced to less than 0.0001 mol / L, to obtain a nano calcium carbonate slurry;

[0027] (6) the nano calcium carbonate slurry obtained in step (5) is concentrated, activated, filtered, dried, and ground to obtain a modified nano calcium carbonate.

[0028] Further, the leaching agent in step (1) is an ammonium chloride solution or an ammonium nitrate solution.

[0029] Further, the soluble carbonate in step (2) is one or a mixture of more than one of sodium carbonate, potassium carbonate, lithium carbonate, ammonium carbonate, and ammonium bicarbonate.

[0030] Further, the amount of soluble carbonate material in step (3) is the same as the amount of calcium hydroxide.

[0031] Further, the amount of calcium source solution added in step (5) is 1.5-21 times the amount of the pre-carbonization calcium source solution in step (3).

[0032] Further, the carbon dioxide volume concentration in step (5) is 30-99%.

[0033] Further, the pressure resistance of the three-stage continuous bubbling carbonization kettle in step (5) is 3 kg / cm 2 .

[0034] The beneficial effects of the present application are that the unique structure of the pre-carbonization kettle provided by the present application is key to forming a pair of nozzles in the same plane, coaxial, opposite, and symmetric, or a plurality of pairs of nozzles in the same plane, coaxial, opposite, and symmetric, respectively, each pair of nozzles spraying the same amount of carbonization agent solution and calcium source solution. The pre-carbonization kettle does not need to be provided with a stirring device, only a cleaning nozzle needs to be provided at the top, which is beneficial to shorten the reaction time and reduce the power consumption. Then, the intermittent bubbling carbonization tower or the three-stage continuous pressurized bubbling carbonization reaction technology is adopted, which strengthens the pre-carbonization reaction by impingement, is beneficial to the instantaneous formation of a large number of crystal nuclei, can effectively control the product particle size, improve the product quality, and improve the production efficiency, and the three-stage continuous carbonization process significantly improves the utilization rate of high-concentration carbon dioxide.

[0035] The pre-carbonization reaction is strengthened by impingement, which is beneficial to the instantaneous formation of a large number of crystal nuclei, can effectively control the product particle size, improve the product quality, and improve the production efficiency, and the three-stage continuous carbonization process significantly improves the utilization rate of high-concentration carbon dioxide BRIEF DESCRIPTION OF DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor on the basis of the provided drawings.

[0037] Figure 1 The accompanying drawings are process flow diagrams for producing nano calcium carbonate provided by the present application;

[0038] Figure 2 The accompanying drawings are schematic diagrams of the pre-carbonization kettle structure provided by the present application;

[0039] In the drawings, the structure represented by each reference numeral is listed as follows: 1-pre-carbonization kettle, 2-crystal seed slurry tank, 3-first stage carbonization kettle, 4-second stage carbonization kettle, 5-third stage carbonization kettle, 6-first stage slurry tank, 7-second stage slurry tank, 8-third stage slurry tank, 9-concentration tank, 10-saponification kettle, 11-activation kettle, 12-concentrated slurry tank, 13-carbonization agent nozzle, 14-calcium source nozzle, 15-cleaning nozzle, 16-crystal seed outlet. DETAILED DESCRIPTION

[0040] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0041] In the description of this invention, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0042] Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0043] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0044] Example 1

[0045] An apparatus for producing nano-calcium carbonate by composite carbonization with opposing even-numbered nozzles, comprising a pre-carbonization kettle body 1.

[0046] The pre-carbonization kettle 1 has a cleaning nozzle 15 at the top and a seed outlet 16 at the bottom.

[0047] The pre-carbonization kettle 1 is equipped with a carbonizing agent nozzle 13 and a calcium source nozzle 14, and the carbonizing agent nozzle 13 and the calcium source nozzle 14 are centrally symmetrical about the center of the pre-carbonization kettle body.

[0048] In one embodiment, the cleaning nozzle 15 is provided with several.

[0049] In another embodiment, the carbonizing agent nozzle 13 is provided with several, the calcium source nozzle 14 is provided with several; The number of carbonizing agent nozzle 13 and calcium source nozzle 14 is the same.

[0050] Embodiment 2

[0051] (1) The wet-process calcium carbide slag after pressure filtration is used as a calcium source and added to a sealed leaching tank containing an ammonium chloride leaching agent. Under the condition of electric stirring, the leaching reaction is carried out, and after filtration, a clear and transparent calcium chloride solution with a concentration of 2 mol / L and saturated with ammonia is obtained, which does not contain solid impurities;

[0052] (2) The sodium carbonate solution is configured into a 2 mol / L carbonizing agent;

[0053] (3) A pre-carbonation kettle device is used to spray 10L of calcium source solution through the calcium source nozzle and 10L of carbonizing agent through the carbonizing agent nozzle into the inside of the pre-carbonation kettle body. The calcium source solution and the carbonizing agent complete the pre-carbonation reaction in an instant through the impact of the opposite spraying, forming a calcium carbonate seed slurry;

[0054] (4) Immediately after the pre-carbonation reaction is completed, the calcium carbonate seed slurry is discharged, and then the cleaning nozzle at the top of the pre-carbonation kettle is opened to spray clean water for washing. The cleaning liquid is mixed into the seed slurry;

[0055] (5) A three-stage continuous bubbling carbonation kettle is used:

[0056] 1) The calcium carbonate seed slurry and 90L of calcium source solution are poured into the first-stage carbonation kettle, carbon dioxide with a concentration of 90% is introduced, and the stirring device in the first-stage carbonation kettle is turned on. At the same time, the calcium ion concentration and pH value detection instrument are opened. When the calcium ion concentration in the first-stage carbonation kettle is reduced to below 0.67 mol / L, the first-stage carbonation slurry is discharged and sent to the first-stage slurry tank;

[0057] 2) The carbonation slurry in the first-stage slurry tank is sent to the second-stage carbonation kettle, and the carbon dioxide coming out of the top of the first-stage carbonation kettle is sent to the bottom of the second-stage carbonation kettle for carbonation reaction again. When the calcium ion concentration in the second-stage carbonation kettle is reduced to below 0.22 mol / L, the slurry coming out of the second-stage carbonation kettle is discharged and temporarily stored in the second-stage slurry tank;

[0058] 3) The slurry in the second-stage slurry tank is transferred to the third-stage carbonation kettle, and the carbon dioxide coming out of the top of the second-stage carbonation kettle is sent to the bottom of the third-stage carbonation kettle for carbonation reaction again. Ammonia is added before the reaction to ensure that the calcium ions can react completely, until the calcium ion concentration is reduced to below 0.0001 mol / L, and the nano calcium carbonate slurry is obtained;

[0059] (6) The nano calcium carbonate slurry obtained in step (5) is concentrated, activated, filtered, dried, and ground to obtain modified nano calcium carbonate. The product quantity is 19.3 kg, and the average particle size is 80 nm. The mother liquor obtained after filtration is an ammonium chloride solution, which can be recycled for leaching.

[0060] Example 3

[0061] (1) Dry carbide slag is used as a calcium source and added to a sealed leaching tank containing an ammonium nitrate leaching agent. Under the condition of electric stirring, the leaching reaction is carried out, and after filtration, a clear and transparent calcium source solution is obtained, which does not contain solid impurities, has a calcium nitrate concentration of 3 mol / L, and ammonia water is in a saturated state;

[0062] (2) The ammonium carbonate solution is prepared into a 3 mol / L carbonizing agent;

[0063] (3) The 16 L calcium source solution is sprayed into the pre-carbonation kettle through the calcium source nozzle, and the 16 L carbonizing agent is sprayed into the pre-carbonation kettle through the carbonizing agent nozzle. The calcium source solution and the carbonizing agent complete the pre-carbonation reaction in an instant through impingement, forming a calcium carbonate seed slurry;

[0064] (4) Immediately after the pre-carbonation reaction is completed, the calcium carbonate seed slurry is discharged, and then the cleaning nozzle at the top of the pre-carbonation kettle is opened to spray clean water for washing. The cleaning liquid is mixed into the seed slurry;

[0065] (5) A three-stage continuous bubbling carbonation kettle is used:

[0066] 1) The calcium carbonate seed slurry and 84 L of calcium source solution are poured into the first-stage carbonation kettle, carbon dioxide with a concentration of 99% is introduced, and the stirring device in the first-stage carbonation kettle is turned on. At the same time, the calcium ion concentration and pH value detection instrument are opened. When the calcium ion concentration in the first-stage carbonation kettle is reduced to below 1 mol / L, the first-stage carbonation slurry is discharged and sent to the first-stage slurry tank;

[0067] 2) The carbonation slurry in the first-stage slurry tank is sent to the second-stage carbonation kettle, and the carbon dioxide from the top of the first-stage carbonation kettle is sent to the bottom of the second-stage carbonation kettle for further carbonation reaction. When the calcium ion concentration in the second-stage carbonation kettle is reduced to below 0.33 mol / L, the slurry from the second-stage carbonation kettle is discharged and temporarily stored in the second-stage slurry tank;

[0068] 3) The slurry in the second-stage slurry tank is transferred to the third-stage carbonation kettle, and the carbon dioxide from the top of the second-stage carbonation kettle is sent to the bottom of the third-stage carbonation kettle for further carbonation reaction. Before the reaction, ammonia water is added to ensure that the calcium ions can react completely. Until the calcium ion concentration is reduced to below 0.0001 mol / L, nano calcium carbonate slurry is obtained. The carbon dioxide in the tail gas after the third-stage carbonation kettle is reduced to about 10%;

[0069] (6) The nano calcium carbonate slurry obtained in step (5) is concentrated, activated, filtered, dried, and ground to obtain modified nano calcium carbonate. The product quantity is 29.2 kg, and the average particle size is 60 nm. The mother liquor obtained after filtration is an ammonium nitrate solution, which can be recycled for leaching.

[0070] Example 4

[0071] (1) Dry carbide slag is used as a calcium source and added to a sealed leaching tank containing an ammonium chloride leaching agent. Under the condition of electric stirring, the leaching reaction is carried out, and after filtration, a clear and transparent calcium chloride solution with a concentration of 2 mol / L and saturated ammonia water is obtained, which does not contain solid impurities;

[0072] (2) The potassium carbonate solution is prepared into a 2 mol / L carbonizing agent;

[0073] (3) The 6L calcium source solution is sprayed into the pre-carbonation kettle through the calcium source nozzle, and the 6L carbonizing agent is sprayed into the pre-carbonation kettle through the carbonizing agent nozzle. The calcium source solution and the carbonizing agent complete the pre-carbonation reaction in an instant through impingement, forming a calcium carbonate seed slurry;

[0074] (4) Immediately after the pre-carbonation reaction is completed, the calcium carbonate seed slurry is discharged, and then the cleaning nozzle at the top of the pre-carbonation kettle is opened to spray clean water for washing. The cleaning liquid is mixed with the seed slurry;

[0075] (5) A three-stage continuous bubbling carbonation kettle is used:

[0076] 1) The calcium carbonate seed slurry and 94L calcium source solution are poured into the first-stage carbonation kettle, and 80% carbon dioxide is introduced while the stirring device in the first-stage carbonation kettle is turned on. At the same time, the calcium ion concentration and pH value detection instruments are turned on. When the calcium ion concentration in the first-stage carbonation kettle is reduced to below 0.67 mol / L, the first-stage carbonation slurry is discharged and poured into the first-stage slurry tank;

[0077] 2) The carbonation slurry in the first-stage slurry tank is poured into the second-stage carbonation kettle, and the carbon dioxide from the top of the first-stage carbonation kettle is poured into the bottom of the second-stage carbonation kettle for further carbonation reaction. When the calcium ion concentration in the second-stage carbonation kettle is reduced to below 0.22 mol / L, the slurry from the second-stage carbonation kettle is discharged and temporarily stored in the second-stage slurry tank;

[0078] 3) The slurry in the second-stage slurry tank is transferred to the third-stage carbonation kettle, and the carbon dioxide from the top of the second-stage carbonation kettle is poured into the bottom of the third-stage carbonation kettle for further carbonation reaction. Before the reaction, ammonia water is added to ensure that the calcium ions can react completely, until the calcium ion concentration is reduced to below 0.0001 mol / L, obtaining a nano calcium carbonate slurry;

[0079] (6) The nano calcium carbonate slurry obtained in step (5) is concentrated, activated, filtered, dried, and ground into powder to obtain modified nano calcium carbonate. The product is 19.4 kg in quantity and 130 nm in average particle size. The mother liquor obtained after filtration is an ammonium chloride solution, which can be recycled for the leaching process.

[0080] In the description of the present specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and integrate different embodiments or examples described in the present specification.

[0081] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method for producing nano-sized calcium carbonate by a compound carbonization of an opposite type even nozzle, characterized in that, The device for producing nano calcium carbonate by adopting the opposed even nozzle composite carbonization includes a pre-carbonization kettle body; The top end of the pre-carbonization kettle body is provided with a cleaning nozzle, and the bottom end of the pre-carbonization kettle is provided with a seed outlet; the inside of the pre-carbonization kettle is provided with carbonization agent nozzles and calcium source nozzles, and the carbonization agent nozzles and the calcium source nozzles are centrally symmetric with the center inside the pre-carbonization kettle body; The cleaning nozzle is provided with a plurality of cleaning nozzles; the carbonization agent nozzles are provided with a plurality of carbonization agent nozzles, and the calcium source nozzles are provided with a plurality of calcium source nozzles; the number of the carbonization agent nozzles and the calcium source nozzles is the same; It includes the following steps: (1) Dry carbide slag or wet carbide slag after pressure filtration is added as a calcium source into a sealed leaching tank containing a leaching agent, the amount of substance of ammonium ion in the leaching agent is 105-110% of the amount of substance of calcium hydroxide, and the leaching reaction is carried out under the condition of electric stirring, and after filtration, a clear and transparent calcium source solution without solid impurities is obtained; the leaching agent is an ammonium chloride solution or an ammonium nitrate solution; (2) Dissolve the soluble carbonate in water to prepare a carbonization agent; (3) Calculate the amount of calcium ions in the calcium source solution, and the amount of substance of carbonate in the carbonization agent is equal to the amount of substance of calcium ions; then the calcium source solution passes through the calcium source nozzle, and the carbonization agent passes through the carbonization agent nozzle to spray into the inside of the pre-carbonization kettle body, and the calcium source solution and the carbonization agent complete the pre-carbonization reaction in an instant by impinging and colliding, forming a calcium carbonate seed slurry; (4) Immediately after the pre-carbonization reaction is completed, the calcium carbonate seed slurry is discharged, and then the cleaning nozzle at the top of the pre-carbonization kettle is opened to spray clean water for washing, and the cleaning liquid is mixed into the seed slurry; (5) A three-stage continuous bubbling carbonization kettle is used: 1) The calcium carbonate seed slurry is poured into the first-stage carbonization kettle, and the calcium source solution is added again, the amount of substance of the added calcium source solution is 1.5-21 times of the pre-carbonization calcium source solution in step (3), carbon dioxide is introduced, and the stirring device in the first-stage carbonization kettle is started, at the same time, the calcium ion concentration and pH value detection instrument are opened, when the calcium ion concentration in the first-stage carbonization kettle is reduced to less than one third of the inlet concentration, the first-stage carbonization slurry is discharged and sent to the first-stage slurry tank; 2) The carbonization slurry in the first-stage slurry tank is sent to the second-stage carbonization kettle, at the same time, the carbon dioxide from the top of the first-stage carbonization kettle is sent to the bottom of the second-stage carbonization kettle for carbonization reaction again, when the calcium ion concentration in the second-stage carbonization kettle is reduced to less than one third of the inlet concentration, the slurry from the second-stage carbonization kettle is discharged and temporarily stored in the second-stage slurry tank; 3) The slurry in the second-stage slurry tank is transferred to the third-stage carbonization kettle, at the same time, the carbon dioxide from the top of the second-stage carbonization kettle is sent to the bottom of the third-stage carbonization kettle for carbonization reaction again, ammonia water is added before the reaction to ensure that the calcium ions can be completely reacted, until the calcium ion concentration is reduced to less than 0.0001 mol / L, and a nano calcium carbonate slurry is obtained; (6) The nano calcium carbonate slurry obtained in step (5) is concentrated, activated, filtered, dried, and ground to obtain modified nano calcium carbonate.

2. The method of claim 1, wherein the method is a method of producing nano-sized calcium carbonate by a complex carbonation using an even number of opposed nozzles, and The soluble carbonate in step (2) is one or more of sodium carbonate, potassium carbonate, lithium carbonate, ammonium carbonate, and ammonium bicarbonate.

3. The method for producing nano-calcium carbonate by composite carbonization with opposing even-numbered nozzles according to claim 1, characterized in that, The carbon dioxide concentration in step (5) is 30-99% by volume.

4. The method of claim 1, wherein the method is a method of producing nano-sized calcium carbonate by a complex carbonation using an even number of opposed nozzles, and The pressure resistance of the three-stage continuous bubbling carbonization kettle in step (5) is 3 kg / cm 2 .

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