Method and system for producing calcium carbonate

Abstract

Provided are a method and a system for producing calcium carbonate with which it is possible to control the content of alkali contained in the obtained calcium carbonate using calcium-containing waste. A method for producing calcium carbonate by producing calcium carbonate from calcium-containing waste, the method comprising: a calcium dissolution step for dissolving calcium by adding hydrochloric acid water to the calcium-containing waste to produce an aqueous solution containing calcium ions; a separation step for adjusting the hydrogen ion concentration index of the aqueous solution containing calcium ions and separating Mg and the like from the aqueous solution; and a calcium carbonate preparation step in which an aqueous solution containing potassium carbonate and / or sodium carbonate is added to the calcium ion-containing aqueous solution obtained by the separation step, and calcium carbonate is produced by reacting the aqueous solution with the calcium ion-containing aqueous solution. Kappa represented by a specific formula is set to 3000 or less by controlling the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate.

Description

Technical Field

[0001] The present invention relates to a method and a system for producing calcium carbonate, and in particular to a method and a system for producing calcium carbonate, which control the alkali content in the obtained calcium carbonate by controlling the reaction rate of a calcium ion-containing solution and an alkali solution. Background Art

[0002] Calcium carbonate is used in a wide range of industrial fields, including fillers such as plastics, paper, and paints, soil conditioners such as pesticides and fertilizers, food additives, and cosmetic raw materials.

[0003] Calcium carbonate is synthesized by blowing carbon dioxide into an aqueous solution of calcium hydroxide, or by mixing an aqueous solution containing calcium ions such as calcium chloride and an aqueous solution of sodium carbonate.

[0004] As shown in Japanese Patent Publication No. 2012-96975 (Patent Document 1), in order to reduce carbon dioxide as a greenhouse gas, calcium carbonate is sometimes generated in the process of fixing carbon dioxide. In Patent Document 1, in order to supply a large amount of calcium, waste materials such as waste concrete or steel slag or calcium-containing wastes such as rocks are utilized.

[0005] In addition, in Patent Document 1, nitric acid is used as a method for dissolving calcium from calcium-containing waste, but at this stage, not only calcium is dissolved, but other elements such as magnesium are also dissolved in the aqueous solution. In Patent Document 1, an aqueous solution of sodium carbonate generated by contacting sodium hydroxide with carbon dioxide is introduced into an aqueous solution containing calcium nitrate or magnesium nitrate, so that calcium carbonate or magnesium carbonate is precipitated.

[0006] In Japanese Patent Gazette No. 2021-79377 (Patent Document 2), a method for fixing carbon dioxide is disclosed, which includes a first contact step and a second contact step, in which a solution containing sodium hydroxide is brought into contact with a gas containing carbon dioxide, and in the second contact step, after the first contact step, at least one of a chloride of a Group 2 element and a chloride of a divalent metal element is added to the solution.

[0007] However, if calcium solution containing calcium waste is simply mixed with a sodium carbonate solution obtained by contacting a solution containing sodium hydroxide with a gas containing carbon dioxide to synthesize calcium carbonate without control, there is a technical problem that a large amount of alkali is contained in the obtained product.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2012-96975

[0011] Patent Document 2: Japanese Patent Application Publication No. 2021-79377 Summary of the invention

[0012] Problem that the invention aims to solve

[0013] The technical problem to be solved by the present invention is to solve the above-mentioned problems, thereby providing a method and a system for producing calcium carbonate that can control the content of alkali contained in the obtained calcium carbonate by using calcium-containing waste.

[0014] Solutions for solving problems

[0015] In order to solve the above-mentioned technical problems, the manufacturing method and manufacturing system of calcium carbonate of the present invention have the following technical features.

[0016] (1) The method for producing calcium carbonate of the present invention is a method for producing calcium carbonate from calcium-containing waste, characterized in that the method comprises: a calcium dissolution step of adding hydrochloric acid water to the calcium-containing waste to dissolve calcium and generate an aqueous solution containing calcium ions; a separation step of adjusting the hydrogen ion concentration index of the aqueous solution containing calcium ions to separate a component containing at least one selected from the group consisting of Si, Al, Mg and heavy metals from the aqueous solution; and a calcium carbonate preparation step of adding an aqueous solution containing potassium carbonate and / or sodium carbonate to the calcium ion-containing aqueous solution obtained in the separation step to react with each other to prepare calcium carbonate, wherein the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate is controlled so that κ represented by the following formula becomes 3000 or less.

[0017] κ=(CaCO3 generation rate (γcc)×(potassium or sodium concentration in the solution after the reaction)) / (1-α)

[0018] Among them, in the above formula,

[0019] CaCO3 generation rate (γcc) = [(addition rate of aqueous solution containing potassium carbonate and / or sodium carbonate) × (concentration of aqueous solution containing potassium carbonate and / or sodium carbonate)] / amount of solution after reaction (mmol-CaCO3 / L / min)

[0020] α (calcium reaction rate) = CO3 / Ca (α≤1, CO3 is the carbonate ion content in potassium carbonate and / or sodium carbonate solution, Ca is the calcium content in calcium ion solution)

[0021] (2) The method for producing calcium carbonate according to (1) above, wherein the addition rate and concentration of the aqueous solution containing potassium carbonate and / or sodium carbonate are controlled so that κ becomes 30 or less.

[0022] (3) The method for producing calcium carbonate according to (1) above, wherein hydrochloric acid water is added to the calcium-containing waste to dissolve the calcium and generate an aqueous solution containing calcium ions.

[0023] (4) The method for producing calcium carbonate according to (1) or (3) above, characterized in that the aqueous solution of potassium carbonate and / or sodium carbonate used in the step of preparing calcium carbonate is produced by contacting carbon dioxide with an aqueous solution containing potassium hydroxide and / or sodium hydroxide.

[0024] (5) The method for producing calcium carbonate according to (4) above, wherein the carbon dioxide is combustion waste gas containing carbon dioxide discharged from a cement manufacturing facility.

[0025] (6) The method for producing calcium carbonate according to (1) or (3) above, wherein the calcium-containing waste contains desalinated dust obtained from a desalination bypass portion of a cement manufacturing facility.

[0026] (7) The calcium carbonate production system of the present invention is a calcium carbonate production system for producing calcium carbonate from calcium-containing waste, characterized in that the calcium carbonate production system comprises: a calcium carbonate dissolving mechanism for adding hydrochloric acid water to the calcium-containing waste to dissolve calcium and produce an aqueous solution containing calcium ions; a separation mechanism for adjusting the hydrogen ion concentration index of the aqueous solution containing calcium ions to separate components containing at least one selected from the group consisting of Si, Al, Mg and heavy metals from the aqueous solution; and a calcium carbonate preparation mechanism for preparing calcium carbonate using the aqueous solution obtained by the separation mechanism and an aqueous solution containing potassium carbonate and / or sodium carbonate, wherein the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate is controlled by the calcium carbonate preparation mechanism so that κ represented by the following formula becomes less than 3000.

[0027] κ=(CaCO3 generation rate (γcc)×(potassium or sodium concentration in the solution after the reaction)) / (1-α)

[0028] Among them, in the above formula,

[0029] CaCO3 generation rate (γcc) = [(addition rate of aqueous solution containing potassium carbonate and / or sodium carbonate) × (concentration of aqueous solution containing potassium carbonate and / or sodium carbonate)] / amount of solution after reaction (mmol-CaCO3 / L / min)

[0030] α (calcium reaction rate) = CO3 / Ca (α≤1, CO3 is the carbonate ion content in potassium carbonate and / or sodium carbonate solution, Ca is the calcium content in calcium ion solution)

[0031] (8) The calcium carbonate production system according to (7) above is characterized in that the addition rate and concentration of the aqueous solution containing potassium carbonate and / or sodium carbonate are controlled so that κ becomes 30 or less.

[0032] (9) The calcium carbonate manufacturing system according to (7) or (8) above is characterized in that it also has a potassium carbonate and / or sodium carbonate generating mechanism: the potassium carbonate and / or sodium carbonate aqueous solution used in the calcium carbonate manufacturing mechanism used in the manufacturing mechanism is generated by bringing carbon dioxide into contact with an aqueous solution containing potassium hydroxide and / or sodium hydroxide.

[0033] (10) The calcium carbonate production system according to (9) above is characterized in that the carbon dioxide used is carbon dioxide exhausted from cement production equipment.

[0034] (11) The calcium carbonate production system according to (7) above is characterized in that the calcium-containing waste contains desalinated dust obtained from a desalination bypass portion of a cement production facility.

[0035] Effects of the Invention

[0036] The production method of the present invention can control the amount of alkali contained in the prepared calcium carbonate to produce calcium carbonate containing a desired amount of alkali, and in particular, can produce calcium carbonate with a reduced alkali content.

[0037] Therefore, the calcium carbonate with a reduced alkali content obtained by the method of the present invention can be used as a cement raw material or the like.

[0038] Furthermore, when calcium carbonate is produced, calcium is produced using calcium-containing waste, and carbon dioxide can also be produced using combustion waste gas, thereby promoting effective utilization of waste.

[0039] In particular, impurities such as Mg can be easily removed from an aqueous solution containing calcium simply by adjusting the hydrogen ion concentration index, and thus the production process of calcium carbonate will not be complicated.

[0040] Furthermore, the manufacturing system of the present invention can effectively implement the above-mentioned manufacturing method of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a flow chart of an example of the method for producing calcium carbonate of the present invention.

[0042] Figure 2 This is a diagram showing an example of producing calcium carbonate using calcium carbonate and carbon dioxide according to the present invention.

[0043] Figure 3 This is a graph showing the relationship between κ, which is an index when preparing calcium carbonate, and the alkali content (Na2O) contained in the obtained calcium carbonate.

[0044] Figure 4 It is a magnified representation Figure 3 Part of the diagram. DETAILED DESCRIPTION

[0045] Hereinafter, with reference to the accompanying drawings, the method for producing calcium carbonate of the present invention and a production system will be described by way of preferred examples.

[0046] like Figure 1 As shown, the production method of the present invention is a calcium carbonate production method (calcium carbonate production system) for producing calcium carbonate from calcium (Ca)-containing waste, which comprises: a calcium dissolution step (calcium dissolution mechanism), in which hydrochloric acid water is added to the calcium-containing waste to dissolve calcium and produce an aqueous solution containing calcium ions; a separation step (separation mechanism), in which the hydrogen ion concentration index of the aqueous solution containing calcium ions is adjusted to separate a component containing at least one selected from the group consisting of Si, Al, Mg and heavy metals from the aqueous solution; and a calcium carbonate preparation step (calcium carbonate preparation mechanism), in which calcium carbonate is prepared using the aqueous solution obtained by the separation step (separation mechanism) and an aqueous solution containing potassium carbonate and / or sodium carbonate.

[0047] in addition, Figure 1 In the figure, double-line arrows represent the flow of solids, and single-line arrows represent the flow of liquids.

[0048] In particular, in the above-mentioned manufacturing method (manufacturing system) of the present invention, when an aqueous solution containing potassium carbonate and / or sodium carbonate is added to an aqueous solution containing calcium ions and reacted to generate calcium carbonate (in a calcium carbonate preparation mechanism), the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate is controlled so that κ represented by the following formula becomes less than 3000, preferably less than 30.

[0049] κ=〔(addition rate of aqueous solution containing potassium carbonate and / or sodium carbonate)×(concentration of aqueous solution containing potassium carbonate and / or sodium carbonate)〕 / (1-α)

[0050] Among them, in the above formula,

[0051] CaCO3 generation rate (γcc) = (Na2CO3 solution addition rate × Na2CO3 solution concentration) / solution volume after reaction (mmol-CaCO3 / L / min)

[0052] α (calcium reaction rate) = CO3 / Ca (α≤1, CO3 is the carbonate ion content in potassium carbonate and / or sodium carbonate solution, Ca is the calcium content in calcium ion solution)

[0053] By setting such an index κ to control the rate and concentration of adding the aqueous solution containing potassium carbonate and / or sodium carbonate to the aqueous solution containing calcium ions, the alkali content in the prepared calcium carbonate can be controlled and reduced.

[0054] The slower the addition speed and the more dilute the concentration, the smaller the index κ is, and the less alkali content is contained in the obtained calcium carbonate.

[0055] The calcium material used to prepare the aqueous solution containing calcium ions used in the present invention is not particularly limited as long as it is a material containing calcium. For example, calcium (Ca)-containing waste can be used, and examples thereof include incineration ash of general garbage or industrial garbage, fly ash discharged from thermal power plants, waste slag, waste concrete, ready-mixed concrete sludge, bioash, and desalinated dust obtained from the desalination bypass part of cement manufacturing equipment.

[0056] In particular, as described later, the desalinated dust obtained from the desalination bypass portion of a cement manufacturing facility also contains potassium chloride components and can be preferably used in the present invention.

[0057] The particle size of the Ca-containing waste is adjusted to be within the range of 1000 μm or less (more preferably 500 μm or less) and 100 μm or more. This makes it easy to extract Ca.

[0058] In the Ca dissolution step (Ca dissolution mechanism), hydrochloric acid water is added to the Ca-containing waste after the particle size is adjusted, preferably so that the hydrogen ion concentration index is within the range of pH 5 or less and pH 0.5 or more.

[0059] At this time, washing water may be added as needed. Washing is performed to replace the liquid contained in the solid component with clean water during solid-liquid separation.

[0060] The reaction time required for extracting Ca from the Ca-containing waste is, for example, 120 minutes or less, more preferably 30 minutes or more and 60 minutes or less. Furthermore, the dissolution extraction may be performed in multiple stages (particularly, in a multi-stage countercurrent method).

[0061] The temperature of the aqueous solution containing hydrochloric acid when extracting Ca is preferably above room temperature, more preferably within the range of 20° C. to 70° C. For example, in the case of performing the bipolar membrane electrodialysis (BMED) treatment described later, since the membrane used is an organic membrane, it is preferred to set the temperature of the aqueous solution in consideration of the heat resistance temperature of the membrane.

[0062] In the Ca dissolution step (Ca dissolution mechanism), separation is performed into a residue and a Ca ion-containing aqueous solution, and the residue can be used as a cement raw material in a cement manufacturing facility, for example.

[0063] The aqueous solution containing Ca ions obtained in the Ca dissolution step (Ca dissolution mechanism) contains impurity ions other than Ca. In the separation step (separation mechanism), the impurity ions can be separated by adjusting the hydrogen ion concentration index.

[0064] By adjusting the pH of the aqueous solution containing Ca ions obtained from the Ca dissolution step (Ca dissolution mechanism) to, for example, pH 5 to 6 using sodium hydroxide or potassium hydroxide, Si or Al ions contained in the aqueous solution containing Ca ions can be removed as a gel. Furthermore, washing water such as clean water can be added as needed to wash the solid component. These gels can be used as cement raw materials.

[0065] Then, the pH of the Ca ion-containing aqueous solution after Si or Al ions are removed is adjusted to, for example, pH 7 to 10 using sodium hydroxide or potassium hydroxide, so that heavy metals such as Pb or Cr ions can be separated. Furthermore, washing water such as clean water can be added as needed to wash the solid component.

[0066] In addition, a coagulant may be added to the Ca ion-containing aqueous solution as needed before heavy metal removal. For example, a polymer coagulant or an inorganic coagulant may be cited. As an inorganic coagulant, there are iron salts such as polyferrous sulfate or aluminum salts such as aluminum sulfate and polyaluminum chloride. As a polymer coagulant, as long as a coagulant more suitable for pH and particle properties such as anionic, nonionic, and cationic is used, examples of which include polyacrylamide, sodium polyacrylate, and polyacrylate.

[0067] Furthermore, by adjusting the pH of the Ca ion-containing aqueous solution after the heavy metal ions are removed to 11 to 12 using sodium hydroxide or potassium hydroxide, the contained Mg ions can be removed as a gel. Furthermore, washing water such as clean water can be added as needed to wash the solid component.

[0068] When adding an aqueous solution containing potassium carbonate and / or sodium carbonate to an aqueous solution after separating and removing the above-mentioned unnecessary impurities from an aqueous solution containing Ca ions, the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate is controlled so that the pH of the mixed solution becomes 11.5 to 13 (preferably 12 to 12.5), and calcium carbonate (calcium carbonate manufacturing mechanism) with a controlled alkali (Na2O, K2O) content is manufactured. Next, calcium carbonate and an aqueous solution of potassium chloride and / or sodium chloride are separated, and calcium carbonate is recovered. In fact, if a thermal analyzer (TG) is used to calculate the purity of calcium carbonate based on the weight loss at 550°C to 800°C, a value of 95.7% is obtained.

[0069] Figure 2 It is generalized Figure 1 A schematic diagram of the process (system) for fixing carbon dioxide to produce potassium carbonate / sodium carbonate is also included.

[0070] in addition, Figure 2 In the figure, double-line arrows represent the flow of solids, single-line arrows represent the flow of liquids, and dotted lines represent the flow of gases.

[0071] The hydrochloric acid water used in the Ca dissolution step (Ca dissolution mechanism) as an example for preparing an aqueous solution containing calcium ions is not particularly limited as long as it is hydrochloric acid water. For example, hydrochloric acid water used to generate an aqueous solution containing potassium chloride and / or sodium chloride by bipolar membrane electrodialysis (BMED) treatment (BMED treatment mechanism) can also be exemplified.

[0072] Furthermore, the potassium chloride and / or sodium chloride can also be recycled. Figure 1 An aqueous solution containing potassium chloride and / or sodium chloride after the calcium carbonate.

[0073] The potassium chloride and / or sodium chloride separated from the calcium carbonate after the calcium carbonate production step may be subjected to pretreatment such as removal of fine particles using an MF membrane (filtration membrane) and concentration of the aqueous solution using an RO membrane (reverse osmosis membrane) as required.

[0074] For example, bipolar membrane electrodialysis (BMED) operates by electricity to generate an aqueous solution containing potassium hydroxide and / or sodium hydroxide in addition to hydrochloric acid water.

[0075] And, if Figure 2 As shown, carbon dioxide is brought into contact with an aqueous solution containing potassium hydroxide and / or sodium hydroxide to absorb the carbon dioxide and generate an aqueous solution containing potassium carbonate and / or sodium carbonate.

[0076] The aqueous solution containing potassium carbonate and / or sodium carbonate is suitable for Figure 1 It is used to make calcium carbonate in the calcium carbonate manufacturing process.

[0077] The carbon dioxide may be contained in, for example, combustion exhaust gas from thermal power plants or exhaust gas from cement manufacturing plants, or may be directly absorbed and utilized by absorbing carbon dioxide in the atmosphere.

[0078] In the above-mentioned calcium carbonate manufacturing process (manufacturing mechanism) of the above-mentioned manufacture method of the present invention, by controlling the reaction rate (specifically, addition rate and concentration) of the aqueous solution containing calcium ions and the aqueous solution containing potassium carbonate and / or sodium carbonate, the alkali (Na2O, K2O) content contained in the obtained calcium carbonate can be controlled.

[0079] Specifically, by making the index κ represented by the following formula 3000 or less (preferably 30 or less), calcium carbonate having a reduced alkali content can be produced, and can be effectively used as a cement raw material or the like.

[0080] κ=(CaCO3 generation rate (γcc)×(potassium or sodium concentration in the solution after the reaction)) / (1-α)

[0081] Among them, in the above formula,

[0082] CaCO3 generation rate (γcc) = [(addition rate of aqueous solution containing potassium carbonate and / or sodium carbonate) × (concentration of aqueous solution containing potassium carbonate and / or sodium carbonate)] / amount of solution after reaction (mmol-CaCO3 / L / min)

[0083] α (calcium reaction rate) = CO3 / Ca (α≤1, CO3 is the carbonate ion content in potassium carbonate and / or sodium carbonate solution, Ca is the calcium content in calcium ion solution)

[0084] The following is an example in which sodium carbonate was added to a calcium ion solution, and the results are shown in Table 1. Figure 3 and Figure 4 . Figure 4 It is a magnified representation Figure 3 Part of the diagram.

[0085] In addition, in Table 1, although sodium carbonate is added in excess, if α>1, calcium carbonate will not be generated, so the increase of alkali metal oxide in calcium carbonate is zero. In addition, in the above formula, when α is 1, 1-α is 0, so in the example of Table 1, for convenience, when α=1, it is calculated in the form of (1.001-α).

[0086] [Table 1]

[0087]

[0088] Table 1 Figure 3 and Figure 4 The sodium oxide content value in the calcium carbonate in the present invention refers to the value measured by an energy dispersive fluorescent X-ray analyzer (Epsilon 3, manufactured by Malvern Panalytical Ltd).

[0089] According to Table 1, Figure 3 and Figure 4 The results show that the closer the calcium reaction rate (α) is to 1, the more the sodium content absorbed in the obtained calcium carbonate increases. That is, by slowing down the addition rate of the aqueous solution containing sodium carbonate to the aqueous solution containing calcium ions, the formation rate of calcium carbonate is slowed down, and the alkali content contained in the obtained calcium carbonate is reduced.

[0090] The calcium carbonate obtained by the method (system) of the present invention can be obtained as calcium carbonate with high purity and controlled alkali content without impurities such as magnesium carbonate. If the alkali content in the obtained calcium carbonate is below 0.13% (preferably below 0.1%, more preferably below 0.8%), the calcium carbonate with reduced alkali content can be effectively used as a cement raw material, etc.

[0091] Industrial Applicability

[0092] As described above, according to the method (system) of the present invention, it is possible to produce calcium carbonate which can utilize calcium-containing waste to generate calcium carbonate with high purity and controlled alkali content, and the obtained calcium carbonate can be suitable for filling materials (fillers) such as plastics, paper, coatings, or cosmetic raw materials, etc.

[0093] Also, the calcium carbonate with reduced alkali content can be used not only as a cement raw material but also as an extender material of cement.

Claims

1. A method for producing calcium carbonate, which is a method for producing calcium carbonate from calcium-containing waste, characterized in that: The method comprises: a calcium dissolution step, in which hydrochloric acid water is added to calcium-containing waste to dissolve calcium and generate an aqueous solution containing calcium ions; a separation step, in which the hydrogen ion concentration index of the aqueous solution containing calcium ions is adjusted to separate a component containing at least one selected from the group consisting of Si, Al, Mg and heavy metals from the aqueous solution; and a calcium carbonate preparation step, in which an aqueous solution containing potassium carbonate and / or sodium carbonate is added to the aqueous solution containing calcium ions obtained by the separation step to react with each other to prepare calcium carbonate, wherein the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate is controlled so that κ represented by the following formula becomes less than 3000, κ=(CaCO3 generation rate (γcc)×(potassium or sodium concentration in the solution after the reaction)) / (1-α) Wherein, CaCO3 generation rate (γcc) = [(addition rate of aqueous solution containing potassium carbonate and / or sodium carbonate) × (concentration of aqueous solution containing potassium carbonate and / or sodium carbonate)] / amount of solution after reaction (mmol-CaCO3 / L / min) α (calcium reaction rate) = CO3 / Ca, wherein α≤1, CO3 is the carbonate ion content in the potassium carbonate and / or sodium carbonate solution, and Ca is the calcium content in the calcium ion solution.

2. The method for producing calcium carbonate according to claim 1, wherein The addition rate and concentration of the aqueous solution containing potassium carbonate and / or sodium carbonate are controlled so that κ becomes 30 or less.

3. The method for producing calcium carbonate according to claim 1, wherein Hydrochloric acid water is added to the waste containing calcium to dissolve the calcium, thereby generating an aqueous solution containing calcium ions.

4. The method for producing calcium carbonate according to claim 1 or 3, wherein The aqueous solution of potassium carbonate and / or sodium carbonate used in the step of preparing calcium carbonate is produced by bringing carbon dioxide into contact with an aqueous solution containing potassium hydroxide and / or sodium hydroxide.

5. The method for producing calcium carbonate according to claim 4, wherein As the carbon dioxide, combustion exhaust gas containing carbon dioxide exhausted from cement manufacturing facilities is used.

6. The method for producing calcium carbonate according to claim 1 or 3, wherein The calcium-containing waste comprises desalination dust obtained from the desalination bypass section of a cement manufacturing plant.

7. A calcium carbonate production system, which is a calcium carbonate production system for producing calcium carbonate from calcium-containing waste, characterized in that: The calcium carbonate manufacturing system comprises: a calcium carbonate dissolving mechanism for adding hydrochloric acid water to calcium-containing waste to dissolve calcium and generate an aqueous solution containing calcium ions; a separation mechanism for adjusting the hydrogen ion concentration index of the aqueous solution containing calcium ions to separate a component containing at least one selected from the group consisting of Si, Al, Mg and heavy metals from the aqueous solution; and a calcium carbonate preparation mechanism for preparing calcium carbonate using the aqueous solution obtained by the separation mechanism and an aqueous solution containing potassium carbonate and / or sodium carbonate, wherein the addition rate of the aqueous solution containing potassium carbonate and / or sodium carbonate is controlled by the calcium carbonate preparation mechanism so that κ represented by the following formula becomes less than 3000, κ=(CaCO3 generation rate (γcc)×(potassium or sodium concentration in the solution after the reaction)) / (1-α) Wherein, CaCO3 generation rate (γcc) = [(addition rate of aqueous solution containing potassium carbonate and / or sodium carbonate) × (concentration of aqueous solution containing potassium carbonate and / or sodium carbonate)] / amount of solution after reaction (mmol-CaCO3 / L / min) α (calcium reaction rate) = CO3 / Ca, wherein α≤1, CO3 is the carbonate ion content in the potassium carbonate and / or sodium carbonate solution, and Ca is the calcium content in the calcium ion solution.

8. The calcium carbonate manufacturing system according to claim 7, characterized in that: The addition rate and concentration of the aqueous solution containing potassium carbonate and / or sodium carbonate are controlled so that κ becomes 30 or less.

9. The calcium carbonate manufacturing system according to claim 7 or 8, characterized in that, It also has a potassium carbonate and / or sodium carbonate generating mechanism: The aqueous solution of potassium carbonate and / or sodium carbonate used in the calcium carbonate production mechanism used in the production mechanism is produced by contacting carbon dioxide with an aqueous solution containing potassium hydroxide and / or sodium hydroxide.

10. The calcium carbonate manufacturing system according to claim 9, characterized in that: The carbon dioxide used was carbon dioxide exhausted from cement manufacturing facilities.

11. The calcium carbonate manufacturing system according to claim 10, characterized in that: The calcium-containing waste comprises desalination dust obtained from the desalination bypass section of a cement manufacturing plant.

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