Manufacturing material of sodium bicarbonate and gypsum and manufacturing method for sodium bicarbonate and gypsum using same

Abstract

The present invention relates to a manufacturing method for sodium bicarbonate and gypsum, comprising the steps of: preparing sodium bicarbonate (NaHCO3) by carbonating a raw material including sodium sulfate Na2SO4), an impurity leaching inhibitor, and impurities; and preparing gypsum (CaSO4) by using waste liquid generated in the step of preparing the sodium bicarbonate, wherein the impurity leaching inhibitor includes a sulfur (S)-containing material. According to the present invention, impurities such as mercury (Hg) and lead (Pb) may be prevented from being leached in waste generated during a process of manufacturing sodium bicarbonate and gypsum. Accordingly, as designated waste can now be treated as general waste, a reduction in waste treatment costs can be expected.

Description

Raw materials for manufacturing sodium bicarbonate and gypsum and methods for manufacturing sodium bicarbonate and gypsum using the same

[0001] The present invention relates to a raw material for manufacturing sodium bicarbonate and gypsum containing sodium sulfate, an impurity dissolution inhibitor, and impurities, and a method for manufacturing sodium bicarbonate and gypsum therefrom.

[0002] Sodium bicarbonate (NaHCO3) is used in a variety of applications, including glass manufacturing, water treatment, and food additives. It is also used to remove harmful gases such as sulfur oxides (SOx) emitted from various factories, thermal power plants, and incinerators. Currently, sintering plants at steel mills use sodium bicarbonate as an adsorbent to remove sulfur oxides, and its use is increasing annually to meet increasingly stringent environmental regulations. Importing industrial sodium bicarbonate poses a challenge, as its import price fluctuates significantly depending on overseas economic conditions.

[0003] The reaction that removes sulfur oxides using sodium bicarbonate produces carbon dioxide and sodium sulfate (sodium sulfate, Na2SO4). Currently, this material is being landfilled, resulting in high disposal costs and secondary environmental problems. Therefore, the development of technologies for sodium sulfate regeneration is urgently needed.

[0004] When regenerative brazing of waste from the smelting process is performed, some waste is generated, containing impurities such as mercury (Hg) and lead (Pb). Waste generated during the process is classified as designated waste if it does not undergo further treatment. According to the current Waste Management Act, mercury and lead must be dissolved at levels below 0.005 mg / L and 3 mg / L, respectively, to be classified as general waste. These toxic metals, which are harmful to the human body, require containment of leakage and conversion to less soluble materials for landfill and storage.

[0005] The present invention has been devised in consideration of the above circumstances, and can provide a method for manufacturing sodium bicarbonate and gypsum, which suppresses the generation of carbon dioxide and recycles sodium sulfate.

[0006] The present invention can provide a raw material for manufacturing sodium bicarbonate and gypsum, in which the elution of impurities such as mercury and lead is suppressed, and a method for manufacturing sodium bicarbonate and gypsum using the raw material.

[0007] According to one embodiment of the present invention, raw materials for manufacturing sodium bicarbonate and gypsum include sodium sulfate (Na2SO4), an impurity dissolution inhibitor, and impurities.

[0008] The above raw material may contain an impurity release inhibitor in an amount of 0.01 wt% or more and 5 wt% or less based on the total weight of the raw material.

[0009] The above impurity dissolution inhibitor may contain a sulfur-containing substance in an amount of 10 wt% or more and 90 wt% or less based on the total weight of the impurity dissolution inhibitor.

[0010] The above sulfur-containing substance may be one selected from sodium hydrogen sulfide, sodium sulfide, and ICX (Sodium Cellulose Xanthate).

[0011] The above impurities may include at least one selected from the group consisting of lead (Pb), copper (Cu), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), cyanide (CN), potassium (K), calcium (Ca), iron (Fe), and chlorine (Cl).

[0012] A method for producing sodium bicarbonate and gypsum according to another embodiment of the present invention comprises the steps of producing sodium bicarbonate (NaHCO3) by carbonating a raw material including sodium sulfate (Na2SO4), an impurity dissolution inhibitor, and impurities; and the step of producing gypsum (CaSO4) using a waste liquid generated in the step of producing sodium bicarbonate, wherein the impurity dissolution inhibitor includes a sulfur (S)-containing substance.

[0013] The above raw material may contain an impurity release inhibitor in an amount of 0.01 wt% or more and 5 wt% or less based on the total weight of the raw material.

[0014] The above impurity dissolution inhibitor may contain a sulfur-containing substance in an amount of 10 wt% or more and 90 wt% or less based on the total weight of the impurity dissolution inhibitor.

[0015] The above sulfur-containing substance may be one selected from sodium hydrogen sulfide, sodium sulfide, and ICX (Sodium Cellulose Xanthate).

[0016] The above impurities may include at least one selected from the group consisting of lead (Pb), copper (Cu), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), cyanide (CN), potassium (K), calcium (Ca), iron (Fe), and chlorine (Cl).

[0017] In the step of manufacturing the above-mentioned sodium bicarbonate, primary waste containing 3 mg / L or less of the above-mentioned impurities may be generated.

[0018] In the step of manufacturing the above gypsum, secondary waste containing 1.1 mg / L or less of the above impurities may be generated.

[0019] The step of manufacturing the above-mentioned sodium bicarbonate may include a step of manufacturing a mixture by dissolving desulfurized waste in water and then adding an impurity dissolution inhibitor; a step of obtaining a raw material by separating the mixture into solids and liquids; and a step of manufacturing the sodium bicarbonate by carbonating the raw material by adding ammonia water and carbon dioxide to the raw material.

[0020] The step of manufacturing the gypsum may include a step of adding a calcium-containing material to the waste liquid to obtain a slurry; a step of removing ammonia from the slurry and then adding an acidic solution to obtain a second mixture; and a step of separating the second mixture into solid and liquid to manufacture the gypsum.

[0021] According to the method for manufacturing sodium bicarbonate and gypsum using the raw materials for manufacturing sodium bicarbonate and gypsum of the present invention, impurities such as mercury (Hg) and lead (Pb) are prevented from being dissolved in the waste generated during the manufacturing process of sodium bicarbonate and gypsum. Accordingly, designated waste can be treated as general waste, which can be expected to result in a reduction in waste disposal costs.

[0022] Figure 1 is a flow chart schematically showing a method for manufacturing sodium bicarbonate and gypsum according to one embodiment of the present invention.

[0023] Hereinafter, preferred embodiments of the present invention will be described with reference to various examples. However, the embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

[0024] The present invention relates to a method for producing sodium bicarbonate and gypsum from a raw material containing sodium sulfate and an impurity dissolution inhibitor.

[0025] Flue gases from steel mills and sintering plants contain sulfur oxides (SOx). Desulfurization using sodium bicarbonate generates waste desulfurization agents. This desulfurization process using sodium bicarbonate offers the advantage of increased desulfurization efficiency and reduced chemical costs. The heat from the flue gas releases one H2O and one CO2 from two sodium bicarbonate molecules, activating them to form Na2CO3, which has a larger contact surface area.

[0026] 2NaHCO3(s) a Na2CO3(s) + CO2(g) + H2O (g)

[0027] Na2CO3(s) + SO2(g) + 1 / 2O2(g) a Na2SO4(s) + CO2(g)

[0028] However, in the desulfurization process using sodium bicarbonate, carbon dioxide is emitted, as shown in the reaction equation above. Furthermore, when sulfur oxides are removed using sodium bicarbonate, waste converted to sodium sulfate (Na2SO4) is generated.

[0029] Because Mangwha contains sodium, it can be used to produce sodium bicarbonate. Its relatively high pH also facilitates the dissolution of carbon dioxide (CO2), which is necessary during the sodium bicarbonate production process. Using Mangwha waste to regenerate sodium bicarbonate can simultaneously address a variety of issues, including minimizing waste generation, achieving carbon neutrality through carbon dioxide reduction, and stabilizing operations through the internal circulation of sodium bicarbonate.

[0030] Mercury (Hg) and lead (Pb) exist within waste desulfurizers, and in waste generated during the baking soda and gypsum production processes, they exist in the form of mercuric chloride (HgCl2) and lead chloride (PbCl2). Table 1 shows the temperature-dependent solubility of impurities, including mercury and lead. The solubility shown in Table 1 represents the mass (g) of the substance dissolved per 100 mL of water.

[0031] Substance 20 ℃ 40 ℃ 60 ℃ 80 ℃ Mercury chloride (HgCl2) 6.6 10.2 16.3 30.0 Lead chloride (PbCl2) 1.1 1.4 1.9 2.5 Mercury sulfide (HgS) 2.9 x 10 -25 ---Lead sulfide (PbS)6.8 x 10 -13 ---

[0032] As shown in Table 1, mercuric chloride and lead chloride have high solubility. Mercury is classified as designated waste if it is dissolved at 0.005 mg / L or more, and lead is classified as designated waste if it is dissolved at 3 mg / L or more.

[0033] Meanwhile, as can be seen in Table 1, mercury sulfide and lead sulfide have very low solubility and are hardly dissolved.

[0034] The content of mercury and lead present in the waste desulfurizer is in ppm units, and the amount of sulfide ions introduced is also small. The sulfide ions introduced are mercury ions (Hg) present in the solution. 2+ ) and lead ions (Pb 2+ ) to react well with the waste desulfurizer, it is necessary to add sulfide ions when dissolving the waste desulfurizer or to mix it with other substances in the raw material.

[0035] The method for producing sodium bicarbonate and gypsum of the present invention comprises the steps of producing sodium bicarbonate (NaHCO3) by carbonating a raw material including sodium sulfate (Na2SO4), an impurity dissolution inhibitor, and impurities; and the step of producing gypsum (CaSO4) using the waste liquid generated in the step of producing sodium bicarbonate.

[0036] In order to manufacture the above raw material, first, the desulfurization waste including the desulfurization agent and the nitrate can be dissolved in a dissolving agent to manufacture a solution. The dissolving agent can be water (H2O). When the desulfurization waste is dissolved in water, the highly soluble mercuric chloride and lead chloride are converted to mercury (Hg 2+ ) and lead (Pb) 2+ ) can exist in solution in the form of ions.

[0037] Afterwards, an impurity dissolution inhibitor can be added to the solution and stirred. The impurity dissolution inhibitor includes a sulfur (S)-containing substance.

[0038] Sulfur-containing substances contain sulfide ions (S 2- ), if an impurity dissolution inhibitor is added to the solution, mercury sulfide and lead sulfide may be generated. The solution must be alkaline for the mercury sulfide and lead sulfide generation reaction to occur easily. The waste desulfurization agent is alkaline (pH>9), which provides good conditions for generating mercury sulfide and lead sulfide.

[0039] After stirring, the mixture is separated into solid and liquid to obtain solid desulfurization waste (primary waste) and raw material (sodium elution solution).

[0040] The above raw material contains sodium sulfate (Na2SO4), an impurity dissolution inhibitor and impurities.

[0041] The above impurity release inhibitor may contain 10 wt% or more and 100 wt% or less of a sulfur (S)-containing substance. By utilizing the impurity release inhibitor of the present invention, mercury and lead, etc. are not released from waste generated during the process, and thus, designated waste can be treated as general waste, thereby reducing waste disposal costs.

[0042] The above sulfur-containing material may be one selected from sodium bisulfide, sodium sulfide, and sodium cellulose xanthate (ICX). Sulfide ions can exist in various forms. Considering the purity of sodium bisulfide, sodium bisulfide (NaHS), sodium sulfide (Na2S), and sodium cellulose xanthate (ICX) have the advantage of being able to use sodium ions as a raw material for sodium bisulfide.

[0043] The above impurities may include at least one selected from the group consisting of sodium sulfate (Na2SO4), lead (Pb), copper (Cu), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), cyanide (CN), potassium (K), calcium (Ca), iron (Fe), and chlorine (Cl).

[0044] The method for producing sodium bicarbonate and gypsum of the present invention includes a step of producing sodium bicarbonate (NaHCO3) by carbonating a raw material.

[0045] Ammonia water and carbon dioxide can be added to raw materials, reacted in a carbonation reactor to obtain a slurry, and the slurry can be separated into solids and liquids to obtain solids and waste liquid. The solids can be washed and dried to produce sodium bicarbonate.

[0046] The purity of the sodium bicarbonate produced from the step of producing the sodium bicarbonate of the present invention may be 97% or more, and the yield of the sodium bicarbonate may be 75% or more.

[0047] During the manufacturing process of the above-mentioned sodium bicarbonate, primary waste containing the above-mentioned impurities at levels of 3 mg / L or less may be generated. When the impurity content of the primary waste is 3 mg / L or less, the leakage of toxic metals harmful to the human body can be suppressed, and waste disposal costs can be reduced.

[0048] During the above-mentioned gypsum manufacturing step, secondary waste containing the above-mentioned impurities at levels of 1.1 mg / L or less may be generated. If the impurity content in the secondary waste is 1.1 mg / L or less, the leakage of toxic metals harmful to the human body can be suppressed, and waste disposal costs can be reduced.

[0049] The method for producing sodium bicarbonate and gypsum of the present invention includes a step of producing gypsum (CaSO4) using waste liquid generated in the step of producing sodium bicarbonate.

[0050] The step of manufacturing the gypsum may include a step of adding a calcium-containing material to the waste liquid to obtain a slurry. The calcium-containing material may be quicklime. After removing ammonia from the slurry, an acidic solution may be added and stirred to obtain a second mixture. The acidic solution may be a sulfuric acid aqueous solution. Alternatively, the slurry may be subjected to solid / liquid separation to obtain a second solid and a second waste liquid. After aeration of the second waste liquid to remove ammonia, the second solid may be mixed again, and then a sulfuric acid aqueous solution may be added and stirred to obtain a third mixture. Thereafter, the second mixture or the third mixture may be subjected to solid / liquid separation to obtain gypsum and waste water.

[0051] When manufacturing gypsum using waste liquid generated during the manufacturing process of sodium bicarbonate, there are advantages in that the cost of gypsum production can be reduced by recycling raw materials, and the amount of waste discharged can be reduced, thereby preventing environmental pollution.

[0052] The purity of the gypsum manufactured from the step of manufacturing the gypsum of the present invention may be 95% or more, and the yield of the gypsum may be 75% or more.

[0053] Example

[0054] Hereinafter, the present invention will be described in more detail with examples. The following examples are intended to further illustrate the present invention, but are not intended to limit the present invention.

[0055] Example 1

[0056] Steps for manufacturing a bicarbonate

[0057] A solution was prepared by adding 99.93 g of desulfurized waste and 200 mL of water and stirring at 40°C for 1 hour. 0.7 g of sodium sulfide (Na2S) was added to the solution as an impurity dissolution inhibitor so that the weight ratio of sodium sulfide was 0.7 wt% based on the sum of the masses of the desulfurized waste and sodium sulfide, and stirring was further performed at 40°C for 1 hour. After stirring, the mixture was separated into solid and liquid to obtain solid desulfurized waste (primary waste) and raw material (sodium dissolution solution).

[0058] The raw material manufacturing process was repeated until 100 g of primary waste was obtained.

[0059] 100 g of primary waste and 1 L of water were added. The pH was adjusted to between 5.8 and 6.3 using hydrochloric acid. After stirring at room temperature and pressure for 6 hours, the filtrate was filtered (Glass filter GF-B 1 μm).

[0060] The amount of lead (Pb) in the filtrate was confirmed using the Inductively Coupled Plasma (ICP) method, and the amount of mercury (Hg) was confirmed using the Atomic Absorption (AA) method. The results of the mercury (Hg) and lead (Pb) extraction experiments for 100 g of primary waste are shown in Table 2.

[0061] Meanwhile, 90 g of ammonia water and 100 g of carbon dioxide were added to 500 g of the above raw material and reacted in a carbonation reactor to obtain a slurry. The slurry was separated into solid and liquid to obtain solids and waste liquid.

[0062] After washing the above first solid, it was dried in an oven at 50°C for more than 12 hours to obtain sodium bicarbonate.

[0063] The yield and purity of sodium bicarbonate are shown in Table 3. The yield of sodium bicarbonate is determined by the amount of Na in the waste desulfurizer and the produced sodium bicarbonate. + It was calculated based on mol. The purity of the sodium bicarbonate was measured using ICP equipment and XRD (X-ray Powder Diffraction) equipment.

[0064] Steps in making plaster

[0065] 350 g of 25% quicklime slurry was added to 500 g of the waste liquid obtained in the above-mentioned sodium bicarbonate manufacturing step and stirred for 1 hour. After stirring, the slurry was separated into solid and liquid to obtain a second solid and a second waste liquid.

[0066] The above second waste liquid was heated to 80°C and aerated using an inert gas to recover NH3 within the slurry. The second waste liquid from which NH3 was removed through aeration was mixed with the second solid obtained after the solid / liquid separation, and 110 g of a 30 wt% sulfuric acid aqueous solution was added and stirred. Thereafter, solid / liquid separation was performed to obtain gypsum and waste water.

[0067] The yield and purity of gypsum are shown in Table 4. The yield of gypsum is determined by the SO4 content of the waste desulfurizer and the produced gypsum. 2- Calculated on a mol basis. The yield of gypsum was measured by ICP, and the purity of gypsum was measured by XRD.

[0068] Secondary waste was obtained by evaporating and concentrating 1000 g of wastewater obtained in the above plaster manufacturing step for 1 hour at a temperature of 80°C or higher and a pressure of 0.1 bar or lower.

[0069] 100 g of secondary waste and 1 L of water were added. The pH was adjusted to between 5.8 and 6.3 using hydrochloric acid. After stirring at room temperature and pressure for 6 hours, the filtrate was filtered (Glass filter GF-B 1 μm).

[0070] The amount of lead (Pb) in the residue was determined using the ICP method, and the amount of mercury (Hg) was determined using the AA method. The results of the mercury (Hg) and lead (Pb) extraction experiments for 100 g of secondary waste are shown in Table 5.

[0071] Examples 2 to 5

[0072] Sodium bicarbonate and gypsum were manufactured in the same manner as in Example 1, except that 98.7, 98, 97.7, and 96.7 g of desulfurized waste were added, respectively, and 1.3, 2.0, 2.3, and 3.3 g of sodium sulfide were added, respectively.

[0073] Comparative Example 1

[0074] Sodium bicarbonate and gypsum were manufactured in the same manner as in Example 1, except that 100 g of desulfurized waste was added and sodium sulfide was not added.

[0075] Experimental example

[0076] The amount of lead (Pb) in the filtrates of the primary wastes of Examples 2 to 5 and Comparative Example 1 was confirmed using the ICP method, and the amount of mercury (Hg) was confirmed using the AA method. The results of the mercury (Hg) and lead (Pb) elution experiments for 100 g of primary waste are shown in Table 2.

[0077] Na2S (wt%)Hg (mg / L)Pb (mg / L)Comparative Example 10.00.10873.1221Example 10.70.00312.1055Example 21.30.00121.0522Example 32.0Not detectedNot detectedExample 42.3Not detectedNot detectedExample 53.3Not detectedNot detected

[0078] It can be confirmed that in the primary waste of Examples 1 to 5, mercury is detected at 0.005 mg / L or less and lead is detected at 3 mg / L or less.

[0079] The yield and purity of the sodium bicarbonate of Examples 2 to 5 and Comparative Example 1 are shown in Table 3.

[0080] Na2S (wt%)Sodium bicarbonate purity (%)Sodium bicarbonate yield (%)Comparative Example 10.098.577Example 10.798.380Example 21.398.279Example 32.097.981Example 42.398.178Example 53.399.177

[0081] It can be confirmed that there is no difference in the purity and yield of the sodium bicarbonate in Comparative Example 1 and Examples 1 to 5. It can be confirmed that the presence or absence of sodium sulfide does not affect the purity and yield of the sodium bicarbonate.

[0082] The yield and purity of the gypsum of Examples 2 to 5 and Comparative Example 1 are shown in Table 4.

[0083] Na2S (wt%) Gypsum Purity (%) Gypsum Yield (%) Comparative Example 10.095.280 Example 10.797.181 Example 21.396.379 Example 32.095.178 Example 42.396.182 Example 53.397.375

[0084] It can be confirmed that there is no difference in the purity and yield of gypsum between Comparative Example 1 and Examples 1 to 5. It can be confirmed that the presence or absence of sodium sulfide does not affect the purity and yield of gypsum.

[0085] The amount of lead (Pb) in the filtrates of the secondary wastes of Examples 2 and 3 and Comparative Example 1 was confirmed using the ICP (Inductively Coupled Plasma) method, and the amount of mercury (Hg) was confirmed using the AA (Atomic Absorption) method. The results of the mercury (Hg) and lead (Pb) elution experiments for 100 g of secondary waste are shown in Table 5.

[0086] Na2S (wt%)Hg (mg / L)Pb (mg / L)Comparative Example 10.00.06232.7922Example 10.70.01221.0022Example 21.30.00150.0556Example 32.0Not detectedNot detectedExample 42.3Not detectedNot detectedExample 53.3Not detectedNot detected

[0087] It can be confirmed that mercury is detected at 0.005 mg / L or less and lead is detected at 3 mg / L or less in the waste of Examples 1 and 2.

[0088] Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and it will be apparent to those skilled in the art that various modifications and variations are possible within a scope that does not depart from the technical spirit of the present invention described in the claims.

Claims

1. Raw materials for manufacturing sodium bicarbonate and gypsum, including sodium sulfate (Na2SO4), impurity dissolution inhibitors, and impurities.

2. In paragraph 1, A raw material containing 0.01 wt% or more and 5 wt% or less of an impurity release inhibitor based on the total weight of the raw material.

3. In paragraph 1, The above impurity release inhibitor is a raw material containing 10 wt% or more and 100 wt% or less of a sulfur-containing substance based on the total weight of the impurity release inhibitor.

4. In paragraph 3, The above sulfur-containing material is a raw material selected from sodium bisulfide, sodium sulfide, and ICX (Sodium Cellulose Xanthate).

5. A step of producing sodium bicarbonate (NaHCO3) by carbonating a raw material containing sodium sulfate (Na2SO4), an impurity dissolution inhibitor, and impurities; and It includes a step of manufacturing gypsum (CaSO4) using waste liquid generated in the step of manufacturing the above-mentioned sodium bicarbonate. The above impurity release inhibitor comprises a sulfur (S)-containing substance. Method for manufacturing sodium bicarbonate and gypsum.

6. In paragraph 5, A method for manufacturing sodium bicarbonate and gypsum, wherein the above raw material contains an impurity release inhibitor in an amount of 0.01 wt% to 5 wt% based on the total weight of the raw material.

7. In paragraph 5, A method for manufacturing sodium bicarbonate and gypsum, wherein the impurity release inhibitor comprises a sulfur-containing material in an amount of 10 wt% or more and 100 wt% or less based on the total weight of the impurity release inhibitor.

8. In paragraph 5, A method for manufacturing baking soda and gypsum, wherein the sulfur-containing substance is one selected from sodium bisulfide, sodium sulfide and ICX (Sodium Cellulose Xanthate).

9. In paragraph 5, A method for producing sodium bicarbonate and gypsum, wherein the impurities include at least one selected from the group consisting of lead (Pb), copper (Cu), arsenic (As), mercury (Hg), cadmium (Cd), chromium (Cr), cyanide (CN), potassium (K), calcium (Ca), iron (Fe), and chlorine (Cl).

10. In paragraph 5, In the step of manufacturing the above-mentioned solution, A method for manufacturing sodium bicarbonate and gypsum, wherein primary waste containing 3 mg / L or less of the above impurities is generated.

11. In paragraph 5, In the step of manufacturing the above plaster, A method for manufacturing sodium bicarbonate and gypsum, which produces secondary waste containing 1.1 mg / L or less of the above impurities.

12. In paragraph 5, The steps for manufacturing the above-mentioned solution are: A step of preparing a mixture by dissolving desulfurized waste in water and then adding an impurity release inhibitor; A step of obtaining a raw material by separating the solid / liquid of the mixture; and A method for manufacturing sodium bicarbonate and gypsum, comprising a step of manufacturing sodium bicarbonate by adding ammonia water and carbon dioxide to the raw material to carbonate the raw material.

13. In paragraph 5, The steps for manufacturing the above plaster are: A step of obtaining a slurry by adding a calcium-containing material to the above waste liquid; A step of removing ammonia from the above slurry, and then adding an acidic solution to obtain a second mixture; and A method for producing baking soda and gypsum, comprising the step of producing gypsum by separating a second mixture into solid and liquid.

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