KR20190071423A - Method and manufacture equipment for calcium carbonate and sodium hydrogen carbonate - Google Patents

Abstract

The present invention relates to a method for manufacturing calcium carbonate and sodium bicarbonate comprising steps of: supplying an elution agent and carbon dioxide to a calcium-containing material and eluting calcium ions to produce a calcium ion-containing solution; supplying sodium hydroxide to the calcium ion-containing solution to produce calcium carbonate; recovering the calcium carbonate and supplying carbon dioxide-containing gas to remaining filtrate to produce sodium bicarbonate; and recovering the sodium bicarbonate and reusing remaining filtrate as the elution agent. According to the present invention, by increasing extraction efficiency of calcium ions from industrial waste and the like, there is an effect to increase manufacturing efficiency of calcium carbonate and sodium bicarbonate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing calcium carbonate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing calcium carbonate and a calcium carbonate and a manufacturing facility thereof.

Warming caused by global warming is becoming a serious environmental problem, and the main cause of this global warming is the increase of atmospheric greenhouse gases. Carbon dioxide is a typical greenhouse gas that is emitted to the atmosphere in large quantities by the use of fossil fuels. In order to solve environmental problems, it is necessary to develop a technology that treats carbon dioxide stably and economically.

There are thermal power generation, cement industry and petrochemical industry that emit a large amount of carbon dioxide. In the downstream of these industries, a technique of selectively absorbing or adsorbing carbon dioxide in the exhaust gas using a liquid or solid absorbent capable of massive carbon dioxide treatment has been applied. However, as the absorbent is deformed or the energy required to regenerate the absorbent is required, there is a disadvantage that the operation cost is excessively high, and further cost for processing the collected carbon dioxide is required, which limits the industrial utilization.

As a technique to overcome the limitations of such carbon dioxide capture technology, studies have been made to convert carbon dioxide to stable carbonates (CaCO ₃ , NaHCO ₃ ) at the same time.

As a related prior art, Patent Document 1 discloses a method for producing calcium carbonate and sodium bicarbonate by using industrial wastes, and reusing the filtrate after recovering the mineral bubbles as an eluting agent. However, in the filtrate, NaHCO ₃ remains in the solution due to the solubility problem and exists as Na ⁺ and HCO ₃ ^- , and reacts with the CaO component in the industrial waste and precipitates on the surface of the industrial waste in the form of CaCO ₃ . Thus, there is a problem that the extraction of CaO is disturbed.

Patent Document 2 discloses a process for manufacturing a carbon dioxide-stabilized carbon dioxide by using sodium hydroxide produced by electrolysis of sodium chloride as a technique for immobilizing carbon dioxide. This method uses a conventional sodium chloride electrolysis method (Chlor-alkali process) and describes that it can save energy when sodium hydroxide is produced by recovering electricity from hydrogen produced as a by-product in the process. However, Technology.

Patent Document 3 discloses a process for producing calcium carbonate, which is a raw material of cement, from waste cement by using a sodium bicarbonate produced using an electrolysis process of sodium chloride as a rapid precipitant. In this method, hydrogen produced from the anode of the electrolysis cell of sodium chloride is supplied to the anode having the platinum electrode catalyst to produce hydrochloric acid. When the pH is maintained below 14 by supplying carbon dioxide to the anode, the potential difference required for electrolysis is reduced Theoretically, it is suggested that the production power of sodium bicarbonate can be lowered.

However, in order to obtain the potential difference for producing the same current density, the pH difference between the positive electrode and the negative electrode does not greatly affect the reduction of the proposed power cost. In addition, when sodium bicarbonate is directly added to waste cement, there is a problem that elution of alkaline ions is difficult in the production of calcium carbonate.

Patent Document 1: Korean Patent No. 10-1758518 Patent Document 2: U.S. Patent No. 7,732,375 Patent Document 3: U.S. Published Patent Application No. 2010/0230293

An object of the present invention is to provide a method for manufacturing calcium carbonate and a calcium carbonate which can increase the extraction efficiency of calcium ions from a substance containing calcium ions such as industrial wastes, and improve the production efficiency of calcium carbonate and sodium chloride, and a manufacturing facility thereof.

According to an aspect of the present invention, there is provided a method for producing a calcium ion-containing material, comprising: supplying an excipient and carbon dioxide to a calcium-containing material and eluting calcium ions to produce a calcium ion- Supplying sodium hydroxide to the calcium ion-containing solution to produce calcium carbonate; Recovering the calcium carbonate and supplying a carbon dioxide-containing gas to the filtrate to generate a mesophase; And recovering the dyestuff and reusing the remaining filtrate as an eluting agent.

The concentration of carbon dioxide in the calcium ion-containing solution may be 0.02 to 0.2 mol.

The pH of the step of producing calcium carbonate may be 10 or more.

Wherein the calcium-containing material may be at least one selected from lung cement, waste concrete, coal ash, fly ash, steel slag, lower calcium oxide (CaO), calcium chloride (CaCl _2), wollastonite, limestone, olivine, serpentine, asbestos and de mukhoe.

The eluent may be an ammonium salt.

Wherein the carbon dioxide-containing gas is at least one selected from the group consisting of FOG, FINEX off gas, FINT tail gas, BFG (blast furnace gas), converter gas, coal power plant exhaust gas, , Glass-dissolved flue gas, thermal facility flue gas, petrochemical process flue gas, petrochemical process gas, pre-combustion flue gas, and gasifier flue gas.

According to another aspect of the present invention, there is provided an elution reactor in which calcium ions are eluted from a calcium-containing material supplied with an eluent and carbon dioxide; A calcium carbonate reactor in which the calcium ion-containing solution and sodium hydroxide are supplied to produce calcium carbonate; A calcium carbonate reactor in which a calcium carbonate is recovered and a carbon dioxide-containing gas is supplied to the filtrate to produce a carbon dioxide gas; and the filtrate remaining after recovering the carbon dioxide is re-supplied to the elution reactor, And a manufacturing facility for a bamboo tank are provided.

And a solid-liquid separator for separating the calcium carbonate produced in the calcium carbonate reactor.

The solid-liquid separator may further include a solid-liquid separator for separating the neutralizer produced in the neutralization reactor.

According to the present invention, it is possible to increase the extraction efficiency of calcium ions from calcium-containing substances such as industrial wastes, and to improve the production efficiency of calcium carbonate and sodium bicarbonate.

FIG. 1 schematically shows a manufacturing process of calcium carbonate and a sodium bicarbonate according to an embodiment of the present invention.
Figure 2 shows that the carbon dioxide dissolved in water changes speciation with pH.
FIG. 3 shows the dissolution amount of CaCO ₃ according to CO ₂ dissolution amount under the conditions of 0.1 M CaCO ₃ , 1 NH ₄ Cl 1 M, and ₁ M NaHCO ₃ .

Hereinafter, preferred embodiments of the present invention will be described with reference to various embodiments. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing calcium carbonate and a calcium carbonate and a manufacturing facility thereof.

The conventional process for producing bicarbonate and calcium carbonate is a process for producing carbon dioxide and carbon dioxide by forming carbon dioxide or carbon dioxide-captured exhaust gas, industrial by-products containing calcium, and a process of fusing sodium hydroxide (NaOH) NaHCO ₃ ) and calcium carbonate (CaCO ₃ ) at the same time.

Specifically, calcium ions are eluted from industrial by-products containing calcium by using an eluent, and the pH is adjusted by supplying sodium hydroxide to the supernatant containing the eluted calcium ions. Thereafter, calcium carbonate is produced by supplying carbon dioxide. The filtrate remaining after recovering the calcium carbonate is reacted with carbon dioxide in a bath reactor to produce a crude bath. That is, the sodium hydroxide added for the pH control is recycled as the raw material of the sodium bicarbonate, so that the calcium carbonate and the sodium bicarbonate are produced together.

On the other hand, sodium ions (Na ⁺ ) and bicarbonate ions (HCO ₃ ^- ) still remain in the remaining filtrate after recovering the precipitate, which is precipitated due to the high solubility of the sodium hydroxide solution, that is, the solubility in the range of 20 to 96 g / It is present in high concentration. When re-use of the filtrate is the bicarbonate ion contained at a high concentration of the elution agent, industrial by-product this process a hydroxyl group (OH ^-) are generated by eluting with pH rises and the bicarbonate ions due to the carbonate ion (CO ₃ ^2-) . The converted carbonate ion reacts with the calcium ions eluted from the industrial by-products to form calcium carbonate. Such calcium carbonate has a problem in that the calcium ion covers the surface of industrial byproducts such as slag and makes the elution of additional calcium ions difficult.

According to an aspect of the present invention, there is provided a method for producing a calcium ion-containing material, comprising: supplying an excipient and carbon dioxide to a calcium-containing material and eluting calcium ions to produce a calcium ion-containing solution; Supplying sodium hydroxide to the calcium ion-containing solution to produce calcium carbonate; Recovering the calcium carbonate and supplying a carbon dioxide-containing gas to the filtrate to generate a mesophase; And recovering the dyestuff and reusing the remaining filtrate as an eluting agent.

The calcium-containing material is not particularly limited as long as it is a material capable of eluting calcium ions by a leaching agent. For example, industrial waste such as waste cement, waste concrete, coal ash, fly ash, steel slag, It may be at least one selected from calcium chloride (CaCl ₂ ), wollastonite, limestone, olivine, serpentine, asbestos and myrtle.

The leaching agent reacts with the calcium-containing substance and contributes to elution of calcium contained in the calcium-containing substance in the form of calcium ions (Ca ^{2 +} ). The kind of the leaching agent is not particularly limited, but it may be an ammonium salt, The ammonium is preferably at least one selected from ammonium chloride, ammonium nitrate, and ammonium acetate, for example.

When ammonium chloride is used as an eluent to elute calcium ions contained in the steel slag, a calcium ion-containing solution can be produced by the following reaction.

Calcium-containing material + NH ₄ Cl CaCl ₂ + NH ₄ OH (1)

The present invention includes a step of dissolving carbon dioxide by supplying a carbon dioxide-containing gas to the calcium ion-containing solution. As described above, when the filtrate containing the high concentration of bicarbonate ions is reused as the eluting agent, sodium ion (Na ⁺ ) and bicarbonate ion (HCO ₃ ^- ) exist at a high concentration in the filtrate remaining after recovering the medium- (OH < "& gt ^; ) eluted from the calcium-containing substance such as industrial by-products, and the bicarbonate ion is converted to carbonate ion (CO ₃ ^2- ). The converted carbonate ion reacts with the calcium ions eluted from the industrial by-products to form calcium carbonate. Such calcium carbonate covers the surface of industrial byproducts such as slag and makes it difficult to elute additional calcium ions, There are restrictions on the simultaneous production of calcium and sodium bicarbonate.

However, as in the present invention, when a solvent is supplied to a calcium-containing substance and calcium ions are eluted to generate a calcium ion-containing solution, when the carbon dioxide-containing gas is supplied to the calcium ion-containing solution to dissolve the carbon dioxide, The pH of the solution is lowered by the hydrogen ion (H ⁺ ) generated by the industrial waste and the CaCO ₃ formed on the surface of the industrial waste is converted into the Ca ^{2 +} and HCO ₃ ^- forms by the following reaction, by dissolving the CaCO ₃ contained in the material surface is possible to increase the concentration of Ca ²⁺ in the solution. As a result, the elution efficiency of calcium ions is increased. In addition, by converting CO ₃ ^2- , which generates CaCO ₃ in the solution, to HCO ₃ ^- , it is possible to prevent the production of CaCO ₃ .

CaCO ₃ + H ₂ CO ₃ Ca ^{2 +} + 2HCO ₃ ^- (2)

The carbon dioxide-containing gas can be pure carbon dioxide, and if it is a gas containing carbon dioxide, industrial by-product gas or power plant flue gas can also be suitably used. Examples are pure carbon dioxide, FINEX off gas, FINT tail gas, blast furnace gas, converter gas, coal power plant flue gas, gas power plant flue gas, incinerator At least one selected from the group consisting of flue gas, glass-dissolved flue gas, thermal facility flue gas, petrochemical process flue gas, petrochemical process process gas, pre-combustion flue gas, and gasifier flue gas.

The concentration of carbon dioxide dissolved in the calcium ion-containing solution may be 0.2 mol or less (excluding 0), preferably 0.02 to 0.15 mol. If the carbon dioxide concentration is less than 0.02 mol, the number of low amount of dissolution of Ca ^{2 +} and the energy consumed for the dissolution of the dissolved amount of increase in Ca ^{2 +} low carbon dioxide than the carbon dioxide is injected in the case of more than 0.2 mol (pressure, etc.) There is a possibility of excessive consumption.

Next, sodium hydroxide is supplied to the calcium ion-containing solution in which the carbon dioxide is dissolved to adjust the pH to produce the solid calcium carbonate. That is, the present invention is different from a general manufacturing calcium carbonate process, excessive injection of CO ₂ to a process for the dissolution of Ca ^{2 +} and by giving to adjust the pH after the extraction of the Ca ^{2 +} Ca ^{2 +} a HCO used to extract ^_3- To CO ₃ ^2- to produce CaCO ₃ .

Figure 2 shows that the carbon dioxide dissolved in water changes speciation with pH. That is, if the pH range is more than 10, the dissolved carbon dioxide is converted from HCO ₃ ^- to CO ₃ ^2- , and most of the carbonate may be present as carbonate ion (CO ₃ ^2- ) at pH 11 or higher. Therefore, for the formation of calcium carbonate, a condition of pH 10 or more is required, and preferably a pH of at least 11, in which HCO ₃ ^- in the solution is converted to CO ₃ ^2- , is required in the step of forming calcium carbonate.

In the step of producing calcium carbonate, calcium carbonate, which is a high value-added substance, can be produced, and calcium carbonate, which is a solid substance, can be recovered using a solid-liquid separator. The carbon dioxide in the carbon dioxide-containing gas and the sodium ion in the filtrate may be subjected to a reaction as described below to supply the carbon dioxide-containing gas to the filtrate remaining after the calcium carbonate is recovered by the solid-liquid separator.

NH ₃ + NaCl + CO ₂ + H ₂ O NaHCO ₃ + NH ₄ Cl (3)

Since the inside of the reactor in which the helium is produced has a weak basicity of less than pH 11 due to ammonia, the equilibrium state in which the concentration of bicarbonate ions (HCO ₃ ^- ) is relatively higher than the concentration of carbonic acid ions (CO ₃ ^2- ) The bicarbonate ions may be generated through reaction with sodium. The solubility of the mesophilic water in 20 water is 96 g / L, and when the mesophase is formed above the solubility, it is difficult to dissolve in water and can be precipitated. Therefore, the precipitated sodium bicarbonate can be recovered using a solid-liquid separation apparatus.

The filtrate remaining after recovering the dyestuff can be reused as an eluting agent since it contains an ammonium salt. Recovering the sodium bicarbonate and the remaining filtrate, the sodium ions (Na ⁺⁾ and bicarbonate ion (HCO ₃ ^-) may be present, and bicarbonate ion (HCO ₃ ^-) hydroxyl group is supplied as a molten material containing the calcium supplied to the elution reactor (OH ^-) it can be converted by a carbonate ion (CO ₃ ^2-). Further, calcium contained in the calcium-containing material may react with the carbonate ion to produce calcium carbonate. However, as described above, by supplying and dissolving carbon dioxide in the calcium ion dissolution reaction as described above, the pH of the solution is lowered and the CaCO ₃ formed on the surface of the industrial waste is converted into the Ca ^{2 +} and HCO ₃ ^- forms It is possible to dissolve CaCO ₃ on the surface of the calcium-containing material such as industrial by-products to prevent such problems.

According to another aspect of the present invention, there is provided a method for preparing a calcium ion-containing ionic liquid which comprises dissolving calcium ions from a calcium-containing substance by an eluent to produce a calcium ion-containing solution, Elution reactor; A calcium carbonate reactor in which the calcium ion-containing solution and sodium hydroxide are supplied to produce calcium carbonate; A calcium carbonate reactor in which a calcium carbonate is recovered and a carbon dioxide-containing gas is supplied to the filtrate to produce a carbon dioxide gas; and the filtrate remaining after recovering the carbon dioxide is re-supplied to the elution reactor, And a manufacturing facility for a bamboo tank are provided.

The apparatus may further comprise a solid-liquid separator for separating the calcium carbonate produced in the calcium carbonate reactor and a solid-liquid separator for separating the calcium carbonate produced in the neutralization reactor.

The processes performed in the elution reactor, the calcium carbonate reactor, and the heattreator have been described in detail hereinabove, and a detailed description thereof will be omitted.

Example

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples are intended to further illustrate the present invention and are not intended to limit the present invention.

The calcium ion contained in the iron slag was eluted by using ₁ M ammonium chloride (NH ₄ Cl) as an elution agent in a steel slag as an industrial waste.

Calcium carbonate and sodium bicarbonate were prepared using the above calcium ion elution, and the filtrate after recovering the sodium bicarbonate was found to have a concentration of 97 g / L of the sodium bicarbonate dissolved therein due to the solubility of the sodium bicarbonate and the ammonium chloride 1M used as the eluent was present .

Were charged into a leaching tank in order to reuse the filtrate, eluting zero _{CaCO 3 0.1M, NH 4 Cl 1M} , NaHCO 3 1M while dissolving carbon dioxide into 0 ~ 0.6mol level under the conditions shown in Figure 3 and then measuring the Ca ^{2 +} fraction .

Referring to FIG. 3, it can be seen that as the amount of dissolved carbon dioxide increases, the concentration of dissolved Ca ^{2 +} increases.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be obvious to those of ordinary skill in the art.

Claims (9)

Supplying an excipient and carbon dioxide to the calcium-containing material and eluting calcium ions to produce a calcium ion-containing solution;
Supplying sodium hydroxide to the calcium ion-containing solution to produce calcium carbonate;
Recovering the calcium carbonate and supplying a carbon dioxide-containing gas to the filtrate to generate a mesophase; And
And recovering the blanched tank and reusing the remaining filtrate as an eluting agent.
The method according to claim 1,
Wherein the concentration of carbon dioxide in the calcium ion-containing solution is 0.02 to 0.2 mol.
The method according to claim 1,
Wherein the pH of the step of producing calcium carbonate is 10 or more.
The method according to claim 1,
Wherein said calcium-containing material at least one member selected from the group consisting of lung cement, waste concrete, coal ash, fly ash, steel slag, lower calcium oxide (CaO), calcium chloride (CaCl _2), wollastonite, limestone, olivine, serpentine, asbestos and de mukhoe ≪ / RTI >
The method according to claim 1,
Wherein the eluting agent is an ammonium salt.
The method according to claim 1,
Wherein the carbon dioxide-containing gas is at least one selected from the group consisting of FOG, FINEX off gas, FINT tail gas, BFG (blast furnace gas), converter gas, coal power plant exhaust gas, , Glass-dissolved gas, thermal facility exhaust gas, petrochemical process exhaust gas, petrochemical process gas, pre-combustion exhaust gas, and gasifier exhaust gas.
An elution reactor in which calcium ions are eluted from the calcium-containing material to which an eluent and carbon dioxide are supplied;
A calcium carbonate reactor in which the calcium ion-containing solution and sodium hydroxide are supplied to produce calcium carbonate; And
And a neutralization reactor in which calcium carbonate is recovered from the calcium carbonate reactor and the remaining filtrate and carbon dioxide-containing gas are supplied to produce a mesophase,
Wherein the filtrate is recovered and the remaining filtrate is fed back to the elution reactor.
8. The method of claim 7,
Further comprising a solid-liquid separator for separating the calcium carbonate produced in the calcium carbonate reactor.
8. The method of claim 7,
Further comprising a solid-liquid separator for separating the sodium bicarbonate produced in the bath reactor.

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