KR20160000480A - Method and apparatus of NaHCO3 production from filtered solution of desulfurized crude waste - Google Patents

Abstract

The present invention relates to a method and an apparatus for producing sodium bicarbonate (NaHCO_3) by using desulfurized wastewater from a steel mill and, more specifically, to a method and an apparatus for producing sodium bicarbonate (NaHCO_3) which increases a sodium bicarbonate yield by including an evaporation step or a cooling step before a reaction step of sodium bicarbonate, and has high purity and high efficiency by controlling appropriate reaction temperature, pressure, materials, and the amount of the materials in the reaction step.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for synthesizing sodium bicarbonate (NaHCO3) from a desulfurization waste liquid,

The present invention relates to a method and apparatus for synthesizing sodium bicarbonate from a desulfurization waste solution from a steel mill, and more particularly, to a method for producing sodium bicarbonate from a desulfurization waste solution, The present invention relates to a method and an apparatus for synthesizing sodium bicarbonate with high purity and high efficiency by controlling an appropriate reaction temperature, a pressure, a substance to be added, and an amount thereof.

In the desulfurization process at the steelworks, an excessive amount of sodium bicarbonate is used to remove SOx, and after the desulfurization, it is buried as it is, resulting in a great environmental problem. Therefore, it is very important to reduce waste disposal and reduce environmental pollution by collecting spent sodium bicarbonate in the above process. In addition, from the economical point of view, it is also becoming a very important task to obtain a high economic efficiency by developing a process for recovering sodium bicarbonate from a desulfurized waste to be disposed of after use.

Solvay process is known as the recovery process. The Solvay process is a process in which a sodium cation dissolved in waste is reacted with sulfuric acid to convert it to sodium sulfate and then reacted with ammonia and carbon dioxide to convert it to sodium hydrogencarbonate. However, the recovery rate of sodium is unsatisfactory Bichel et al. Developed a process for recovering sodium hydrogencarbonate and ammonium sulfate, but the recovery of sodium was still unsatisfactory.

Therefore, there is an urgent need to develop a simple process capable of regenerating sodium bicarbonate from a desulfurization waste liquid, and a new synthesis apparatus capable of recycling the remaining effluent after the regeneration of sodium bicarbonate is also required.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide sodium bicarbonate from sodium- And a method for synthesizing sodium bicarbonate and an apparatus therefor.

Still another object of the present invention is to provide a new method and apparatus for synthesizing sodium bicarbonate from ammonia and a desulfurization waste liquid used in the present reaction process and recycling the remaining effluent.

The method for synthesizing sodium bicarbonate according to the present invention comprises: a concentration step of concentrating a desulfurization waste liquid; A reaction step in which ammonium bicarbonate or an ammonia solution and carbon dioxide are injected into the concentrated desulfurization waste solution in the concentration step to react; And separating sodium bicarbonate (NaHCO3) and a supernatant from the reaction product produced in the reaction step. At this time, the volume of the supplied desulfurization waste liquid can be concentrated to 40 to 60 vol% by evaporation.

The present invention also provides a process for producing a deasphalted waste liquid, comprising: a cooling step of cooling the desulfurization waste liquid to 2-5 DEG C; A sodium source separation step of separating the sodium source and the supernatant which have been cooled and crystallized in the cooling step; A reaction step in which water, ammonium bicarbonate or ammonia solution and carbon dioxide are injected into the sodium source separated in the separation step and reacted; Separating the reaction product produced in the reaction step into sodium bicarbonate (NaHCO3) and a supernatant; . ≪ / RTI >

In the present invention, the reaction is carried out at a reaction temperature of 25 to 80 ° C., a reaction pressure of 3 to 7 atm, and a reaction molar ratio of sodium source to ammonia may be 1: 0.9 to 1: 1.1.

Further, the present invention may further include, after the separation step, mixing the separated sodium bicarbonate with methanol to improve the purity, and then re-separating the sodium bicarbonate and the supernatant with sodium bicarbonate, Thereafter, further separation and recovery of methanol and ammonia using distillation in the separated supernatant liquid may be further performed. The recovered methanol may be reused in the re-separation step and the ammonia may be reused in the reaction step.

On the other hand, an ammonia stripping step of stripping ammonia from the separated supernatant after the separation step; Separating the sodium sulfate contained in the supernatant from which ammonia has been removed by crystallization and separating the sodium sulfate into a supernatant; And the separated ammonia and sodium sulfate are re-introduced into the reaction step, and the remaining supernatant may be reused to make a desulfurization waste liquid.

An apparatus for synthesizing sodium bicarbonate according to the present invention comprises: a desulfurization waste liquid storage tank (1) storing a desulfurization waste liquid; An evaporator (2) for evaporating and concentrating the desulfurization waste liquid supplied from the desulfurization waste liquid reservoir (1); A reactor (3) for injecting ammonium bicarbonate or ammonia and carbon dioxide into the concentrated desulfurization waste liquid in the evaporator (2) and reacting the same; And a first separator (4) for separating sodium bicarbonate (NaHCO3) and a supernatant from the reaction product produced in the reactor (3)

A desulfurization waste liquid storage tank (1) storing a desulfurization waste liquid; A cooling crystallization tank (15) for cooling the desulfurization waste liquid supplied from the desulfurization waste liquid storage tank (1) to crystallize the sodium source; A fourth separator (16) for separating the supernatant and the sodium source crystallized in the cooling crystallization tank (15); A reactor (3) injecting water and ammonium bicarbonate or ammonia and carbon dioxide into the sodium source separated in the fourth separator (16) and reacting; A first separator (4) for separating sodium bicarbonate (NaHCO3) and a supernatant from the reactant produced in the reactor (3); As shown in FIG.

Further, the present invention may further include a second separator (5) for mixing methanol with sodium bicarbonate separated from the first separator (4) to improve the purity and re-separating the sodium bicarbonate and the sodium bicarbonate into a supernatant.

Also, in the present invention, an ammonia stripper 8 for removing ammonia contained in the supernatant separated from the first separator 4; A crystallization tank (9) for crystallizing sodium sulfate contained in the supernatant from which ammonia is removed from the ammonia stripper (8); And a third separator (10) for separating the sodium sulfate and the supernatant liquid crystallized in the crystallization tank (9); The ammonia separated from the ammonia stripper 8 and the sodium sulfate separated from the third separator 10 are circulated to the reactor 3 for reuse and the supernatant separated from the third separator 10 It can be stored in the supernatant storage tank 11 and reused for producing a desulfurization waste liquid.

The present invention utilizes a method of concentrating a waste liquid by evaporating or cooling the desulfurization waste liquid or a method of cooling the sodium source to crystallize the sodium source. At this time, sodium bicarbonate is synthesized with high purity and high efficiency by appropriately controlling the volume of the desulfurization waste liquid or the cooling temperature There is an effect that can be.

In addition, in the present invention, sodium bicarbonate having higher purity and higher efficiency can be obtained by controlling the reaction temperature, the reaction pressure, the amount of the input material, and the amount of the input material in the reaction step for synthesis of sodium bicarbonate.

In addition, the present invention has the effect of synthesizing sodium bicarbonate having higher purity by mixing and separating methanol from the separated sodium bicarbonate.

Brief Description of the Drawings Fig. 1 is a schematic view showing a method of synthesizing sodium bicarbonate including a process of evaporating a solvent of a de-
2 is a schematic view showing a method of synthesizing sodium bicarbonate including a process of cooling a solvent of a desulfurization waste liquid

A method for synthesizing sodium bicarbonate from a desulfurization waste liquid according to the present invention comprises: a concentration step of concentrating a desulfurization waste liquid; A reaction step in which ammonium bicarbonate or an ammonia solution and carbon dioxide are injected into the concentrated desulfurization waste solution in the concentration step to react; And separating sodium bicarbonate (NaHCO3) and a supernatant from the reaction product produced in the reaction step.

If the concentration of the supplied desulfurization waste liquid is adjusted to be 40 to 60 vol%, the concentration of the desulfurization waste solution is preferably 65 to 90 wt%, more preferably 50 vol% Is best.

In the meantime, the cooling method may be used instead of the method of concentrating the desulfurization waste liquid, wherein the cooling method includes a cooling step of cooling the desulfurization waste liquid to 2 to 5 DEG C instead of the concentration step; And a sodium source separation step of separating the crystallized sodium source and the supernatant after cooling in the cooling step. The subsequent step, the reaction step and the separation step are the same, but when the ammonium bicarbonate is injected in the reaction step, water should be further supplied. Further, the supernatant separated in the sodium source separation step may be stored in the supernatant storage tank 11 and reused as a solvent for dissolving the desulfurization waste.

In the present invention, the reaction step preferably has a reaction temperature of 25 to 80 ° C and a reaction pressure of 3 to 7 atm, and most preferably a reaction temperature of 35 to 38 ° C. . Also, the reaction molar ratio of the sodium source to the ammonia in the reaction step is most preferably 1: 0.9 to 1: 1.1.

In addition, in the present invention, after the separation step, the separated sodium bicarbonate may be mixed with methanol to improve purity, and then re-separated into sodium bicarbonate and a supernatant. Thereafter, further separation and recovery of methanol and ammonia by distillation in the separated supernatant liquid is preferably carried out, so that methanol is reused in the re-separation step, and ammonia is reused in the reaction step.

After the separating step, ammonia stripping is performed to strip ammonia from the separated supernatant. Separating the sodium sulfate contained in the supernatant from which ammonia has been removed by crystallization and separating the sodium sulfate into a supernatant; And the separated ammonia and sodium sulfate are recycled to the reaction step and the remaining supernatant is recycled to make a desulfurization waste liquid.

Hereinafter, the technical idea of the present invention will be described more specifically with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the technical concept of the present invention, are incorporated in and constitute a part of the specification, and are not intended to limit the scope of the present invention.

Figure 1 shows a sodium bicarbonate synthesis process involving evaporation of the desulfurization waste liquid to contain an appropriate amount of water. Hereinafter, the present invention will be described with reference to FIG. 1 and including an evaporation process.

First, a desulfurization waste liquid which has been analyzed for the concentration of sodium source relative to the amount of water contained therein is evaporated in an evaporator 2 and concentrated. Usually, the degree of concentration can be easily adjusted by necessity, but the desulfurization waste liquid supplied to the evaporator 2 is preferably evaporated so that the amount thereof is about 40 to 60 vol%. The volume of the desulfurized waste liquid, which has been reduced to 40 to 60 vol%, is effective in increasing the yield of synthesized sodium bicarbonate to 65 to 90 wt%. At this time, the volume of the optimized water is 50 vol%.

The desulfurized waste liquid concentrated in the evaporator 2 is transferred to the reactor 3. In the reactor (3), ammonium bicarbonate or ammonia solution and carbon dioxide are injected into a desulfurization waste liquid containing a sodium source to react. At this time, the reaction ratio of sodium source to ammonia can be appropriately adjusted, but when the molar ratio is controlled to about 1: 9-1: 1.1, the yield of sodium bicarbonate can be obtained to almost 91 wt%. Previously, ammonia gas was used, but it was not easy to control the ratio of sodium source to ammonia and high yield could not be obtained. Therefore, the present invention using an ammonia solution and CO2 or ammonium bicarbonate is very effective because it can obtain a yield of almost 91 wt%.

The temperature of the reactor 3 is a factor that greatly affects the yield of sodium bicarbonate synthesis. When the temperature is maintained at 25 to 80 캜, more preferably 35 to 38 캜, high purity and a high yield of sodium bicarbonate of 65 to 92 wt% Can be obtained. When ammonia solution and carbon dioxide are used in the reactor 3, they are supplied to the reactor 3 in the ammonia storage tank 13 and the carbon dioxide storage tank 12, respectively.

Keeping the pressure in the reactor 3 at 3-7 atm helps to synthesize sodium bicarbonate with a purity of approximately 92%.

After the reaction is completed in the reactor (3), the produced reactant is transferred to a first separator (4) for separating solid sodium bicarbonate. Particularly, in the present invention, when a solid sodium bicarbonate separated from the first separator 4 is transferred to the second separator 5 and then a small amount of methanol is added thereto, sodium bicarbonate having a higher purity can be obtained . The solid sodium bicarbonate obtained through the second separator 5 is transferred to the dryer 7 and dried and the methanol used in the second separator 5 is filtered and distilled in the still 14 About 95% is recovered and transferred to the methanol storage tank 6 for storage. It is then reused to improve the purity of sodium bicarbonate.

The supernatant separated by the first separator (4) is transferred to an ammonia stripper (8) to store ammonia in the form of ammonium sulfate. Further, the remaining supernatant, from which methanol has been removed from the distiller 14, is also transferred to the ammonia stripper 8. At this time, suitable means may be used for stripping the ammonia, and the stripped ammonia is pressurized and stored in the ammonia storage tank 13. The remaining supernatant after stripping the ammonia in the ammonia stripper 8 is cooled to crystallize the remaining sodium sulfate in the crystallization tank 9. Although the cooling temperature of the crystallization tank can be suitably regulated, it is preferably cooled to 2 to 6 ° C, and most preferably to 5 ° C. The remaining sodium sulphate is separated by maintaining the appropriate temperature in the third separator 10. The separated sodium sulfate is circulated to the reactor (3) and used again for sodium bicarbonate synthesis. Further, the supernatant having a pH of 4 to 5 separated in the third separator 10 can be transferred to the desulfurization waste liquid storage tank 1 and used to dissolve the desulfurization waste.

In the meantime, each separator used in the present invention can be appropriately selected and used according to a person skilled in the art by various means using a centrifugal separation such as a peeler type decanter and a filtration method such as a filter press.

FIG. 2 shows another example of separating the sodium source from the desulfurization waste liquid containing the cooling process of the present invention and synthesizing sodium bicarbonate, and also shows a process of reusing the solvent for dissolving the desulfurization waste. In this case, the same reference numerals are used for the components corresponding to those in Fig.

In the method shown in Fig. 2, a cooling crystallization tank 15 is used instead of the evaporator 2 shown in Fig. 1 for separating the sodium source from the desulfurization waste liquid. The temperature of the cooling crystallization tank 15 is maintained at 2 to 5 캜 for separation of an effective sodium source. The desulfurized waste liquid is transferred from the desulfurization waste liquid storage tank 1 to the cooling crystallization tank 15 to be cooled to crystallize the sodium source and transferred to the fourth separator 16 to separate the sodium source. The separated solid sodium source is transferred to reactor 3 where sodium bicarbonate synthesis requires water and ammonium bicarbonate or ammonia solution and CO2 as described in Figure 1 for synthesis. At this time, the supernatant separated from the fourth separator 16 is immediately transferred to the supernatant reservoir 11 to be used for dissolving the desulfurization waste. The subsequent process is the same as the process described with reference to FIG. 1, and thus will be omitted.

Hereinafter, a specific embodiment of the present invention will be described by way of example, and the present invention is not limited to the following embodiments.

[Example 1]

 11.1 kg of steel desulfurization waste was put into 22 L of water, adjusted to pH 6 with concentrated sulfuric acid, and stirred at 45 캜 for 30 minutes. Then, 0.5 kilogram of non-dissolved component was removed by using a peeler-type decanter equipped with 800 meshes filter at 3500 rpm while maintaining the temperature at 45 ° C, and 20 L of the supernatant was recovered. The recovered solution was analyzed by ICP analysis to determine SO4-2, HCO3-1, and CO3-2 through Na +, IC analysis, and the recovered weights of various Na salts such as NaSO4, Na2CO3, and NaHCO3 were determined. Respectively. As shown in Table 1, the total weight of sodium salt contained in 20 L was 8.269 kg, and 78% of 10.6 kg, excluding 0.5 kg of insoluble impurities, was recovered from 11.1 kg of the desulfurized wastes.

 Then, 8.72 L of 28% NH4OH solution and 13.31 kg of CO2 were added to 20 L of the recovered solution containing the recovered Na salt to synthesize sodium bicarbonate (NaHCO3), reacted at 35 ° C to 38 ° C for 1 hour, 9.713 kg of NaHCO3 precipitates were separated using a peeler type decanter under the same conditions as those used for separating solids from the desulfurization wastes. The major cations and anions contained in the precipitates were quantified using ICP and IC, and the purity of NaHCO3 The ratios of NH4 +, SO4-2, CO3-2 and the like are shown in Table 2.

As shown in Table 2, the purity of NaHCO3 was 85.23%. In the 11.1 kg of the desulfurized waste, the reaction yield was 91.63% converted to NaHCO3 from 10.6 kg excluding 0.5 kg of the insoluble solid.

Desulfurization Waste Weight 11.1kg Volume of water 22L Separation temperature 45 ° C Insoluble fraction separation method peeler type decanter Insoluble Weight 0.5kg Volume of recovered solution 20L The amount of Na salts contained in the recovered solution NaSO ₄ = 6.175 kg
Na ₂ CO ₃ = 1.44 kg
NaHCO ₃ = 0.95kg Total weight of Na salt recovered 8.269kg Na salt recovery 78%

Recovery solution volume for NaHCO ₃ synthesis 20L The amount of CO ₂ for synthesis of NaHCO ₃ 13.31kg NaHCO ₃ 28% NH ₄ OH Volume 8.72L Weight of synthesized NaHCO ₃ 9.71 kg The synthesized NaHCO ₃ Composition NaHCO ₃ = 85.23%
NH ₄ ⁺ = 5.75%
SO ₄ ^-2 = 5.21%
CO ₃ ^-2 = 2.21% The yield of NaHCO ₃ produced relative to the Na salt in the recovered solution 91.63%
9.71 / (11.1-0.5)

[Example 2]

 11.1 kg of steel desulfurization waste was added to 24.2 L of water and stirred at 45 캜 for 30 minutes without pH adjustment. Next, by using a peeler type decanter and a filter press, the non-dissolved components were removed and the supernatant was recovered. The operation conditions of the peeler type decanter were the same as in Example 1, and the filter press was operated at 45 ° C and 4 atm. Table 3 shows the weight of the insolubles, the volume of the recovered solution and the composition of the Na salt in the recovered solution. The analytical method for determining the composition is the same as in Example 1.

 As shown in Table 3, the recovery rate of the 11.1 kg Na salt of the desulfurized waste was 91.93%, the filter press was 90.78%, and the recovered solution volume was 21.2 L and 23.12 L, respectively, as calculated in the same manner as in Example 1.

 To synthesize NaHCO3, 1.42 L and 1.40 L of 28% NH4OH solution were added to 21.2 L and 23.12 L recovered solutions, respectively, as shown in Table 4, and 2 kg and 4.74 kg of CO2 were added, followed by reaction at 35 ° C to 38 ° C for 1 hour The NaHCO3 precipitates synthesized under the conditions of 45 ° C and 3500rpm were separated using an after-peeler type decanter. The precipitates were quantitatively analyzed in the same manner as in Example 1, and the composition of the Na salts was shown in Table 4.

As shown in Table 4, the weight of synthesized NaHCO3 was 8.34 kg and the purity was 92.25%.

Desulfurization Waste Weight 11.1kg Volume of water 24.12L Separation temperature 45 ° C Insoluble fraction separation method peeler type decanter 필터 press Volume of recovered solution 21.2L 23.12L Total weight of insoluble matter 1.68kg 1.21kg Weight of Na salt contained in recovered solution Na ₂ SO ₄ = 7.37 kg
Na ₂ CO ₃ = 0.51 kg
NaHCO ₃ = 0.78kg Na ₂ SO ₄ = 7.66
Na ₂ CO ₃ = 0.99 kg
NaHCO ₃ = 0.33kg Weight of recovered Na salt 8.66 kg 8.98kg Na salt recovery 91.93%
8.66 / (11.1-1.68) 90.78%
8.98 / (11.1-1.21)

Recovery solution volume for NaHCO ₃ synthesis 21.2L 23.12L The amount of CO ₂ for NaHCO ₃ synthesis 10.87 kg 11.68kg 28% NHOH volume for synthetic NaHCO ₃ 7.75L 8.32L Weight of synthesized NaHCO ₃ 7.73kg 8.34kg NaHCO ₃ yield versus Na salt in recovery solution 82.06% 84.33% The synthesized NaHCO ₃ Composition NaHCO ₃ = 82.23%
NH ₄ ⁺ = 1.75
SO ₄ ^-2 = 10.36
CO3 ^-2 = 5.78 NaHCO ₃ = 92.25%
NH ₄ ⁺ = 1.2
SO ₄ ^-2 = 2.3
CO3 ^-2 = 3.28

[Example 3]

 11.1 kg of steel desulfurization waste was charged into 26.2 liters of water and stirred at 45 ° C and 80 ° C for 30 minutes to determine the effect of temperature without pH adjustment. Subsequently, the insoluble components were separated and removed by applying a pressure of 4 atm at 45 ° C and 80 ° C using a filter press, and the supernatant was recovered. The results and conditions are shown in Table 5. At 45 ° C, the weight of the insoluble matter was 3.66 kg, which was much smaller than 6.04 kg at 80 ° C. The weight of the various Na salts contained in the recovered solution was analyzed in the same manner as in the previous examples and shown in Table 5 The total weight of Na salt contained in the solution recovered at 45 캜 was 6.44 kg, which was greater than 4.03 kg at 80 캜.

To synthesize NaHCO 3, 24.24 L of the recovered solution at 45 ° C. and 21.35 L of the recovered solution at 80 ° C. were charged with 6.25 L and 4.16 L of 28% NH 4 OH, 8.78 kg and 5.83 kg of CO2, respectively, After the reaction, the synthesized NaHCO3 precipitates were separated by peeler type decanter under the same conditions as in Examples 1 and 2. The weights of the NaHCO3 precipitates were 4.93 kg and 3.45 kg, respectively, and the purity of NaHCO3 was 90.21% and 85.21% Detailed results are shown.

Desulfurization Waste Weight 11.1Kg Volume of water 26.2L Insoluble fraction separation method 필터 press Separation temperature 45 ° C 80 ℃ Insoluble gross weight 3.66kg 6.04 kg Volume of recovered solution 24.24L 21.35L Weight of Na salts in recovery solution Na ₂ SO ₄ = 5.38 kg
Na ₂ CO ₃ = 0.76 kg
NaHCO ₃ = 0.29kg Na ₂ SO ₄ = 3.99 kg
Na ₂ CO ₃ = 0.12 kg
NaHCO ₃ = 0.1kg Total weight of Na salt recovered 6.44kg 4.03kg Na salt recovery 86.5%
6.44 / (11.1-3.6) 79.64%
4.03 / (11.1-6.04)

Recovery solution volume for NaHCO ₃ synthesis 24.24L 21.35L CO2 amount for NaHCO ₃ Synthesis 8.78kg 5.83kg 28% NH4OH volume for synthetic NaHCO ₃ 6.25L 4.16L Total weight of synthesized NaHCO ₃ 4.93kg 3.45kg Composition of synthesized NaHCO ₃ NaHCO ₃ = 90.21%
NH ₄ ⁺ = 2.75%
SO ₄ ^-2 = 3.56%
CO ₃ ^-2 = 0.00% NaHCO ₃ = 85.21%
NH ₄ ⁺ = 1.20%
SO ₄ ^-2 = 7.89%
CO ₃ ^-2 = 1.2% The yield of NaHCO ₃ produced relative to the Na salt in the recovered solution 66.26%
4.93 / (11.1-3.66) 68.18%
3.45 / (11.1-6.04)

[Example 4]

22L, 23.1L and 24.3L were added to each 11.1kg of steel desulfurization waste to examine the effects of the amount of water supplied to the steel desulfurization waste, and the mixture was stirred at 45 ° C for 30 minutes without pH adjustment.

 Subsequently, the insoluble matter was removed by filtration under the conditions of 45 ° C. and 4 atm, and the supernatant was recovered. The results and conditions are shown in Table 7. The weight of insolubles was 2.33 kg, 2.03 kg and 1.18 kg, respectively. The weight and total weight of various Na salts contained in the recovered solution are shown in Table 7 .

Then, 28% NH4OH solution volume and CO2 amount were added to 20.2L, 22.01L, and 23.4L of each recovery solution obtained by adding 22L, 23.1L, and 24.3L of water to synthesize NaHCO3 as shown in Table 8 After reacting for 1 hour at 35 ~ 38 ℃, the synthesized NaHCO3 precipitates were separated by peeler type decanter under the same conditions as in the previous example. The weights of 7.17kg, 6.73kg and 7.14kg were respectively weighed and NaHCO3 purity was 92.4%, 96.31 %, 98.04%.

Desulfurization waste
weight 11.1kg Separation temperature 45 ° C Insoluble fraction separation method 필터 press Volume of water 22L 23.1L 24.3L Insoluble Weight 2.33kg 2.03kg 1.18kg Volume of recovered solution 20.2L 22.01L 23.40L The amount of Na salts contained in the recovered solution Na ₂ SO ₄ = 4.39 kg
Na ₂ CO ₃ = 1.05 kg
NaHCO ₃ = 2.5kg Na ₂ SO ₄ = 4.52 kg
Na ₂ CO ₃ = 1.25 kg
NaHCO ₃ = 2.59kg Na ₂ SO ₄ = 5.9 kg
Na ₂ CO ₃ = 1.32 kg
NaHCO ₃ = 2.13kg Total weight of Na salt recovered 7.94kg 8.35kg 8.73 kg Na salt recovery 90.53%
7.94 / (11.1-2.33) 92.02%
8.35 / (11.1-2.03) 88.0%
8.73 / (11.1-1.18)

The volume of the collected solution for the synthesis NaHCO ₃ 20.2L 22.01L 23.4L The amount of CO ₂ for NaHCO ₃ synthesis 10.03kg 10.44kg 11.52kg 28% NH ₄ OH volume for NaHCO ₃ synthesis 7.15L 7.44L 8.2L Weight of synthesized NaHCO ₃ 7.17kg 6.73kg 7.14 kg The synthesized NaHCO ₃ Composition NaHCO ₃ = 92.4%
NH ⁴⁺ = 1.1%
SO ₄ ^-2 = 5.6%
CO ₃ ^-2 = 1.5% NaHCO ₃ = 96.31%
NH ⁴⁺ = 1.00%
SO ₄ ^-2 = 1.36%
CO ₃ ^-2 = 1.2% 98.04%
0.00%
0.06%
1.56%

[Example 5]

 In order to investigate the influence of the type of the desulfurization waste discharged from the steelworks, 11.1 kg of the desulfurization waste was sampled at different places, and the mixture was stirred at 45 ° C for 30 minutes without pH adjustment, The insolubles were removed by separation at 4 ° C, and the supernatant was recovered. The detailed conditions and results are shown in Table 9.

 As shown in the table, the weight of the insolubles was varied to 1.1kg, 1.65kg, and 2.55kg depending on the type of waste, and the volume of the recovered solution was found to be 22.5L, 20.57L, and 18.89L, respectively.

Next, to synthesize NaHCO 3, the volume of 28% NH 4 OH solution was calculated under the conditions of the ammonia molar ratio relative to the Na salt of 0.9, and the amount of CO 2 was added as shown in Table 10 and reacted at 35 to 38 ° C for 1 hour. The NaHCO3 precipitates were separated using a peeler type decanter under the same conditions as in the previous examples. The synthesized weights were 7.29 kg, 7.05 kg, 7.64 kg, respectively, and NaHCO3 purity was 83.12%, 92.31%, and 93.04%.

Desulfurization Waste Weight 11.1kg Volume of water 23.1L Separation temperature 45 ° C Insoluble fraction separation method 필터 press Type of desulfurization waste Raw material 1 Raw material 2 Raw material 3 Total weight of insoluble matter 1.1kg 1.65kg 2.55kg Volume of recovered solution 22.5L 20.57L 18.89L The amount of Na salts contained in the recovered solution Na ₂ SO ₄ = 7.92 kg
Na ₂ CO ₃ = 0.92 kg
NaHCO ₃ = 0.36kg Na ₂ SO ₄ = 6.73 kg
Na ₂ CO ₃ = 1.2 kg
NaHCO ₃ = 0.76kg Na ₂ SO ₄ = 7.13 kg
Na ₂ CO ₃ = 1.56 kg
NaHCO ₃ = 0.79kg Total weight of Na salt recovered 8.57kg 8.69 kg 9.48kg Na salt recovery 85.7%
8.57 / (11.1-1.1) 91.95%
8.69 / (11.1-16.5) 110.87%
9.48 / (11.1-2.55)

Recovery solution volume for NaHCO ₃ synthesis 22.5L 20.57L 18.89L 28% NH ₄ OH solution volume for NaHCO ₃ synthesis 8.21L 7.96L 8.08L The amount of CO ₂ for NAHCO ₃ synthesis 11.53kg 11.18kg 11.35kg Weight of synthesized NaHCO ₃ 7.29kg 7.05kg 7.64kg The synthesized NaHCO ₃ Composition NaHCO ₃ = 83.12%
NH ⁴⁺ = 5.62%
SO ₄ ^-2 = 5.6%
CO ₃ ^-2 = 4.12% NaHCO ₃ = 92.31%
NH ⁴⁺ = 3.00%
SO ₄ ^-2 = 1.36%
CO ₃ ^-2 = 2.2% NaHCO ₃ = 93.04%
NH ⁴⁺ = 0.00%
SO ₄ ^-2 = 0.1%
CO ₃ ^-2 = 1.56%

[Example 6]

11.1 kg of steel desulfurization waste was added to 22.2 liters of water and stirred at 45 ° C for 30 minutes without adjusting the pH to check the effect of cooling and adjusting the insoluble fraction so that the amount of water suitable for the desulfurization waste solution was contained. Subsequently, insolubles were removed by distillation at 45 ° C and 4atm using a filter press, and the supernatant was recovered. The results and conditions are shown in Table 11. The recovered solution was subjected to a crystallization process at 5 ° C. for 1 hour and the recovered Na salt crystals were dissolved at 45 ° C. to recover 9.5 L of Na salt-containing solution for NaHCO 3 synthesis and the weight of various Na salts was analyzed. Respectively. To synthesize NaHCO3, 6.67 L of 28% NH4OH and 10.90 kg of CO2 were added as shown in Table 12 and reacted at 35-38 DEG C for 1 hour. Then, peeler type decanter was added at 45 DEG C and 3500 rpm as in the previous example. , And then about 3 ~ 5L of methanol was added to the second step to improve the purity of NaHCO3 and to make the particle diameter uniform and small. The yield of NaHCO3 synthesized under the above conditions was 4.7 kg, 66.99%, and the purity was 92.3%.

Desulfurization Waste Weight 11.1kg Volume of water 22.2L Separation temperature 45 ° C Insoluble fraction separation method 필터 press Insoluble gross weight 1.665kg Volume of recovered solution 20.64L Cooling temperature for water ratio control 5 ℃ Recovered solution volume after cooling separation 9.29L Weight of Na salt contained in recovered solution after cooling Na2SO4 = 4.722 kg Na2CO3 = 1,795 kg NaHCO3 = 0.617 kg Total weight of Na salt recovered after cooling 7.135kg Recovery rate of Na salt after cooling 75.62%
7.135 / (11.1-1.665)

Volume of recovered solution for NaHCO3 synthesis 9.29L CO2 amount for NaHCO3 synthesis 10.90 kg For the synthesis of NaHCO3
Volume of 28% NH4OH 6.67L The volume of metal stock 3.3L Weight of synthesized NaHCO3 4.78kg NaHCO3 yield relative to Na salt in recovered solution 66.99% Synthesized NaHCO3 composition
NaHCO ₃ = 92.3%
NH ⁴⁺ = 1.2%
SO ₄ ^-2 = 5.00%
CO ₃ ^-2 = 1.5%

[Example 7]

To investigate the effect of evaporating the solution after insoluble matter separation so that the amount of water in the desulfurization waste solution is different, 11.1 kg of the iron oxide desulfurization waste was put into 22.5 L of water and stirred at 45 ° C for 30 minutes without pH control. Subsequently, the insoluble matter was removed by distillation at 45 ° C and 4atm using a filter press, and the supernatant was recovered. The detailed results and conditions are shown in Table 13. The recovered 21.5 L of solution was evaporated at about 30% water for about 12 hours at 80-90 ° C to remove 12.07 L and make up to 9.34 L for use in NaHCO 3 synthesis.

In order to synthesize NaHCO3, 8.734 L of 28% NH4OH and 14.29 kg of CO2 were added as shown in Table 14 and reacted at 35 to 38 ° C for 1 hour. Then, peeler type decanter And then about 3 ~ 5 L of methanol was added to improve the purity of the produced NaHCO3 and to make the particle diameter uniform and small. As shown in Table 14, NaHCO3 synthesized under the above conditions showed a yield of 86.9% at 9.21 kg and a purity of 92.3%.

Desulfurization Waste Weight 11.1kg Volume of water 22.5L Separation temperature 45 ° C Insoluble fraction separation method 필터 press Insoluble gross weight 0.5kg Volume of recovered solution 21.5L Evaporation temperature for water ratio control 80 to 90 ° C Volume of recovered solution after evaporation 9.43L Weight of Na salt in solution after evaporation Na2SO4 = 6.185 kg Na2CO3 = 1.044 kg NaHCO3 = 0.98 kg Total weight of Na salt recovered after evaporation 8.209kg Recovery rate of Na salt after evaporation 77.44%
8.209 / (11.1-0.5)

Volume of recovered solution for NaHCO3 synthesis 9.34L CO2 amount for NaHCO3 synthesis 14.29 kg 28% NH4OH < / RTI > volume for NaHCO3 synthesis 8.734L Added methanol volume 3.3L Weight of synthesized NaHCO3 9.214L NaHCO3 yields versus Na salt in recovery solution 86.29% Synthesized NaHCO3 composition NaHCO ₃ = 92.3%
NH ⁴⁺ = 3.17%
SO ₄ ^-2 = 2.00%
CO ₃ ^-2 = 2.01%

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

1: Desulfurization waste liquid storage tank 2: Evaporator
3: Reactor 4: First separator
5: Second separator 6: Methanol storage tank
7: dryer 8: ammonia stripper
9: Crystallization tank 10: Third separator
11: supernatant storage tank 12: carbon dioxide storage tank
13: NH3 storage tank 14: still water
15: cooler 16: fourth separator

Claims (12)

A concentration step of concentrating the desulfurization waste liquid;
A reaction step in which ammonium bicarbonate or an ammonia solution and carbon dioxide are injected into the concentrated desulfurization waste solution in the concentration step to react;
Separating the reaction product produced in the reaction step into sodium bicarbonate (NaHCO3) and a supernatant;
≪ / RTI > wherein the sodium bicarbonate is sodium bicarbonate.
A cooling step of cooling the desulfurization waste liquid to 2 to 5 캜;
A sodium source separation step of separating the sodium source and the supernatant which have been cooled and crystallized in the cooling step;
A reaction step of injecting water, ammonium bicarbonate or ammonia solution and carbon dioxide into the sodium source separated in the sodium source separation step, and reacting;
Separating the reaction product produced in the reaction step into sodium bicarbonate (NaHCO3) and a supernatant;
≪ / RTI > wherein the sodium bicarbonate is sodium bicarbonate.
The method according to claim 1,
And the volatilization of the supplied desulfurization waste liquid to be 40 to 60 vol%
A method for synthesizing sodium bicarbonate from a desulfurization waste liquid.
3. The method according to claim 1 or 2,
Wherein the reaction temperature is from 25 to 80 DEG C and the reaction pressure is from 3 to 7 atm,
A method for synthesizing sodium bicarbonate from a desulfurization waste liquid.
3. The method according to claim 1 or 2,
The reaction molar ratio of sodium source to ammonia is 1: 0.9 to 1: 1.1,
A method for synthesizing sodium bicarbonate from a desulfurization waste liquid.
3. The method according to claim 1 or 2,
Separating the separated sodium bicarbonate with methanol to improve the purity, and separating the separated sodium bicarbonate and sodium bicarbonate into a supernatant;
≪ / RTI > further comprising a dehydrogenation catalyst.
7. The method of claim 6,
Further separating and recovering methanol and ammonia using distillation in the separated supernatant,
The recovered methanol is reused in the re-separation step, and ammonia is reused in the reaction step, wherein sodium bicarbonate is synthesized from the desulfurization waste.
3. The method according to claim 1 or 2,
An ammonia stripping step of stripping ammonia from the separated supernatant;
Separating the sodium sulfate contained in the supernatant from which ammonia has been removed by crystallization and separating the sodium sulfate into a supernatant;
Further comprising:
Separated ammonia and sodium sulfate are re-introduced into the reaction step, and the remaining supernatant is reused to make a desulfurization waste solution.
A method for synthesizing sodium bicarbonate.
A desulfurization waste liquid storage tank (1) storing a desulfurization waste liquid;
An evaporator (2) for evaporating and concentrating the desulfurization waste liquid supplied from the desulfurization waste liquid reservoir (1);
A reactor (3) for injecting ammonium bicarbonate or ammonia and carbon dioxide into the concentrated desulfurization waste liquid in the evaporator (2) and reacting the same;
A first separator (4) for separating sodium bicarbonate (NaHCO3) and a supernatant from the reactant produced in the reactor (3);
Wherein the desulfurization waste liquid contains sodium bicarbonate.
A desulfurization waste liquid storage tank (1) storing a desulfurization waste liquid;
A cooling crystallization tank (15) for cooling the desulfurization waste liquid supplied from the desulfurization waste liquid storage tank (1) to crystallize the sodium source;
A fourth separator (16) for separating the supernatant and the sodium source crystallized in the cooling crystallization tank (15);
A reactor (3) injecting water and ammonium bicarbonate or ammonia and carbon dioxide into the sodium source separated in the fourth separator (16) and reacting;
A first separator (4) for separating sodium bicarbonate (NaHCO3) and a supernatant from the reactant produced in the reactor (3);
Wherein the desulfurization waste liquid contains sodium bicarbonate.
The sodium bicarbonate synthesizing apparatus according to claim 9 or 10,
A second separator (5) for separating sodium bicarbonate separated from the first separator (4) into methanol and sodium bicarbonate and then separating the sodium bicarbonate and the sodium bicarbonate into a supernatant;
Further comprising a desulfurization waste liquid containing sodium bicarbonate.
The sodium bicarbonate synthesizing apparatus according to claim 9 or 10,
An ammonia stripper (8) for removing ammonia contained in the supernatant separated in the first separator (4);
A crystallization tank (9) for crystallizing sodium sulfate contained in the supernatant from which ammonia is removed from the ammonia stripper (8); And
A third separator (10) for separating the sodium sulfate and the supernatant liquid crystallized in the crystallization tank (9);
Further comprising:
Ammonia separated from the ammonia stripper 8 and sodium sulfate separated from the third separator 10 are circulated to the reactor 3 for reuse and the supernatant separated from the third separator 10 is returned to the supernatant reservoir 11 ), Which is reusable to make a desulfurization waste liquid,
An apparatus for synthesizing sodium bicarbonate from a desulfurization waste liquid.

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