WO2018088727A1 - Method for purifying waste hydrochloric acid - Google Patents

Abstract

The present invention relates to a method for purifying waste hydrochloric acid and, specifically, to a method for purifying waste hydrochloric acid, comprising the steps of: (S1) preparing an extraction solution by dissolving an extractant in an organic solvent; (S2) extracting a metal component with an organic solvent by injecting the extraction solution into waste hydrochloric acid; (S3) phase separating a water hydrochloric acid layer and the organic solvent containing the metal component; and (S4) obtaining purified hydrochloric acid by recovering the phase separated (fractionated) water hydrochloric acid layer, wherein at least 40 mol of the extractant is used on the basis of 1 mol of Fe contained in the waste hydrochloric acid, and the waste hydrochloric acid and the extraction solution are mixed in a volume ratio of waste hydrochloric acid : extraction solution of 1 to 0.1-1.

Description

Waste hydrochloric acid purification method

Cross Citation with Related Applications

This application claims the benefit of priority based on Korean Patent Application No. 10-2016-0148633 dated November 09, 2016 and Korean Patent Application No. 10-2017-0138499 dated October 24, 2017. All content disclosed in the literature is included as part of this specification.

Technical Field

The present invention relates to a method for purifying waste hydrochloric acid.

Ethylene dichloride (1,2-dichloroethane, EDC) is a substance produced during the reaction of vinyl chloride monomer synthesis (see Scheme 1 below), which is a direct chlorine method through the reaction of ethylene and chlorine, ethylene, hydrogen chloride and air (oxygen). It can be prepared by the chlorine oxide method by the reaction of).

Scheme 1

C ₂ H ₄ + Cl ₂ (or HCl) → CH ₂ = CHCl + CH ₂ ClCH ₂ Cl

CH ₂ ClCH ₂ Cl → CH ₂ = CHCl + HCl

On the other hand, a constant amount of by-products such as spent hydrochloric acid (or dilute hydrochloric acid) are continuously generated in the production of the ethylene dichloride.

When these waste hydrochloric acids are recycled into hydrochloric acid in the chlor-alkali electrolyzer anolyte, or recycled as oxy-chlorination raw materials, the plant can reduce the emissions of hazardous substances and reduce the cost of purchasing hydrogen chloride. Red and economic benefits can occur. Therefore, various methods for purifying and recycling waste hydrochloric acid have been studied in order to reduce manufacturing costs.

In order to recycle the waste hydrochloric acid, various metal components such as Fe, Al, Ca, K, Mg, and Ni remaining in the waste hydrochloric acid need to be removed. If the cations of such metals are present in the anolyte, they react with OH ^- ions on the surface or inside of the membrane in the electrolytic cell, causing hydroxides, which leads to a decrease in voltage rise and current efficiency. .

In particular, most of the metal components, except for Fe, are removed when the water used in the ethylene dichloride process is replaced with de-minerals water, while Fe remains in waste hydrochloric acid because An additional purification process is required to remove Fe from.

Currently, the most common method for removing Fe is to remove free residual chlorine in waste hydrochloric acid, and then separate FeCl ₃ using an ion exchange resin.

Since the free residual chlorine present in the spent hydrochloric acid causes severe deactivation of the active site of the ion exchange resin, the free residual chlorine must be removed before the Fe refining process is performed.

The free residual chlorine is removed by vacuum dechlorination, steam / air stripping, sulfite addition, active carbon, and UV method. Etc. can be used.

The vacuum (decompression) desalting method is a method of removing Cl ₂ through pressure control, and can be combined with the existing anolyte desalting method. However, there are disadvantages in that the process is complicated, high process cost and low removal efficiency. The steam / air stripping method has a disadvantage in that energy consumption is large and additional investment costs are generated by stripping through steam or air. In addition, the sulfite addition method is a method of reducing Cl ₂ through an oxidation reaction of sulfite, such as Na ₂ SO ₃ , NaHSO ₃ , to sulfate, as in Scheme 2 below, and this method also removes free residual chlorine efficiency. This low, existing SRS system (Sulfate Removal System) can overload the sulfate treatment.

 Scheme 2

NaHSO ₃ + HOCl → NaHSO ₄ + HCl

The method of using activated carbon is a method of adsorbing Cl ₂ using activated carbon, and it is troublesome to consider efficiency in a strong acid atmosphere and to consider a gas target and a liquid target.

The UV method is a process of selectively removing free residual chlorine using UV energy as shown in Scheme 3, and it is reported that HOCl is well absorbed at a wavelength of 238 nm. However, this method also has the disadvantage of increased process cost and low free chlorine removal efficiency.

Scheme 3

Cl ₂ + H ₂ O → HOCl + HCl

2HOCl → O ₂ + 2HCl

As described above, various methods for removing free residual chlorine before Fe removal have been proposed, but when the pH is very low, such as waste hydrochloric acid, below 0.8, there is a problem that it is not easy to remove free residual chlorine below 5 ppm. .

In addition, in the general method of separating FeCl ₃ using the ion exchange resin, since the free residual chlorine removed water is regenerated and used, a two-stage purification process is required. Therefore, the process equipment and maintenance costs are increased, it is difficult to apply to the actual process.

As such, the conventional method of removing Fe from waste hydrochloric acid has a problem of not only high energy and cost consumption because of complicated process steps, but also low free chlorine removal efficiency from waste hydrochloric acid.

Therefore, while reducing energy consumption and cost, it is necessary to develop a high purity waste hydrochloric acid purification method.

Prior art literature

(Patent Document 1) US Patent No. 2,787,525

(Patent Document 2) Japanese Patent Publication No. 3511244

In order to solve the above problems, a first object of the present invention is to provide a waste hydrochloric acid purification method using a solvent extraction method.

Specifically, in one embodiment of the present invention

Dissolving the extractant in an organic solvent to prepare an extraction solution (S1);

Injecting the extraction solution into the waste hydrochloric acid to extract metal components in the waste hydrochloric acid with an organic solvent (S2);

Phase separation of the organic solvent containing the metal component and the waste hydrochloric acid layer (S3); And

Recovering the phase separation (fractionated) hydrochloric acid layer to obtain purified hydrochloric acid (S4); and

The amount of the extractant is 40 mol or more based on 1 mol of iron (Fe) ions among the metal components contained in the waste hydrochloric acid,

The waste hydrochloric acid: extract solution is 1: 1 to 1: 1 to provide a waste hydrochloric acid purification method to be mixed.

In the hydrochloric acid purification method of the present invention, the organic solvent used to prepare the extraction solution may include at least one solvent selected from the group consisting of an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent, and an alcohol.

Specifically, the aromatic hydrocarbon solvent may include at least one selected from the group consisting of toluene and xylene.

The aliphatic hydrocarbon solvent is at least one cycloaliphatic hydrocarbon solvent selected from the group consisting of methyl cyclohexane and cyclohexane, or a linear hydrocarbon solvent having 6 to 20 carbon atoms, such as kerosene (kerosene, kerosene), normal hexane, heptane, octane, And one or more selected from the group consisting of nonane, decane, and dodetan.

The alcohol may include a monohydric alcohol having 6 to 20 carbon atoms.

In addition, the extracting agent may be at least one or more selected from the group consisting of trioctylamine, methyl isobutyl ketone, trialkylphosphine oxide and tributyl phosphate, specifically selected from the group consisting of trioctylamine and methyl isobutyl ketone It may be at least one, more specifically trioctylamine.

The amount of the extractant may be 40 mol to 60 mol based on 1 mol of the iron (Fe) ion component among the metal components contained in the waste hydrochloric acid.

As described above, in the case of the waste hydrochloric acid purification method using the solvent extraction method according to the present invention, since the metal component, especially the iron (Fe) ion component can be effectively removed to 1 ppm or less from the waste hydrochloric acid, the recycling efficiency of hydrochloric acid Can improve.

In addition, the waste hydrochloric acid purification method using the solvent extraction method of the present invention can be repeated several times through the regeneration of the solvent used, resulting in a simplification of the process compared to the existing process, thereby reducing energy and manufacturing costs have.

The following drawings, which are attached to this specification, illustrate exemplary embodiments of the present invention, and together with the contents of the present invention serve to further understand the technical idea of the present invention, the present invention is limited to the matters described in such drawings. It is not to be construed as limited.

1 is a flowchart illustrating a waste hydrochloric acid purification method using the solvent extraction method of the present invention.

2 is a process schematic diagram of a method for purifying waste hydrochloric acid using the solvent extraction method of the present invention.

Figure 3 is a photograph comparing the color change of hydrochloric acid before and after purification of the purified hydrochloric acid using the solvent extraction method of the present invention.

Hereinafter, the present invention will be described in more detail.

The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

Conventional methods for removing metal components, particularly iron (Fe) ions, from spent hydrochloric acid are not only costly and energy consuming because of the complex process steps, including free residual chlorine removal, but also free residual chlorine and There is a disadvantage in that the removal efficiency of the iron (Fe) ion component is also low.

Therefore, in the present invention, even if the organic residual chlorine component removal step from the waste hydrochloric acid is not additionally performed using the solvent extraction method, the metal component, particularly the iron (Fe) ion component, can be effectively removed to 1 ppm or less, specifically 0.1 ppm or less. It is possible to reduce the energy consumption and cost, and at the same time provide a method for purifying waste hydrochloric acid with high purity.

Specifically, in one embodiment of the present invention

Dissolving the extractant in an organic solvent to prepare an extraction solution (S1);

Injecting the extraction solution into the waste hydrochloric acid to extract metal components in the waste hydrochloric acid with an organic solvent (S2);

Phase separation of the organic solvent containing the metal component and the waste hydrochloric acid layer (S3); And

Recovering the phase separation (fractionated) hydrochloric acid layer to obtain purified hydrochloric acid (S4); and

The amount of the extractant is 40 mol or more based on 1 mol of iron (Fe) ions among the metal components contained in the waste hydrochloric acid,

The waste hydrochloric acid: extract solution is 1: 1 to 1: 1 to provide a waste hydrochloric acid purification method to be mixed.

Specifically, FIG. 1 is a flowchart illustrating a waste hydrochloric acid purification method using the solvent extraction method of the present invention according to exemplary embodiments. 2 is a process schematic diagram of a method for purifying waste hydrochloric acid using the solvent extraction method of the present invention.

First, the method for purifying hydrochloric acid of the present invention may further include a step (S0) of measuring the concentration of iron (Fe) ion component among the metal components included in the waste hydrochloric acid before the step (S1) of preparing the extraction solution. have.

At this time, the concentration of iron (Fe) ions of the metal components contained in the waste hydrochloric acid can be measured by an inductively coupled plasma mass spectrometry (Inductively coupled plasma mass spectrometry). Specifically, the method measured about 5g of the sample in a corning tube (corning tube) was added as an internal standard, diluted with 25 mL of ultrapure water and analyzed using an ICP-OES (Optima 7300 DV) apparatus.

In addition, referring to Figure 1, the hydrochloric acid purification method of the present invention may include the step of preparing an extraction solution by dissolving the extractant in an organic solvent (S1).

At this time, the organic solvent is a (dilution) solvent used to improve the physical properties such as viscosity, specific gravity, etc. of the organic phase, and to control the concentration of the extractant, and representative examples thereof include aromatic hydrocarbon solvents, aliphatic hydrocarbon solvents, and alcohols. It may include at least one solvent selected from the group consisting of.

Specifically, the aromatic hydrocarbon solvent may include at least one selected from the group consisting of toluene and xylene.

The aliphatic hydrocarbon solvent is at least one cycloaliphatic hydrocarbon solvent selected from the group consisting of methyl cyclohexane and cyclohexane, or a linear hydrocarbon solvent having 6 to 20 carbon atoms, specifically kerosene (kerosene, kerosene), normal hexane, heptane, octane And nonane, decane, and dodetan.

In addition, the alcohol may include a monohydric alcohol having 6 to 20 carbon atoms, and representative examples thereof include 2-ethyl hexanol, 2-dodecanol, and the like.

The organic solvent may be affected by the extraction equilibrium and the extraction rate according to the hydrocarbon content, specifically, the organic solvent is a phase separation with water smoothly, selectivity to the metal (selectivity) ) Is higher than water, and it is preferable to use toluene which shows the lowest value of TOC (total organic carbon) after the extraction process.

At this time, the TOC value is a value that can know how much the extractant or diluent is contained by checking the concentration of organic impurities contained in the purified high purity hydrochloric acid after the extraction process.

In addition, the extractant may be used as a compound for ion exchange reaction, at least one selected from the group consisting of trioctylamine, methyl isobutyl ketone, trialkylphosphine oxide and tributyl phosphate as a representative example, Among them, the phase separation effect is higher than that of the trialkylphosphine oxide or tributyl phosphate, which is a phosphorus-based extractant, and it is easy to remove metal components, particularly iron (Fe) ions, from waste hydrochloric acid, and reuse the organic solvent used in the purification process And it is more preferable to use trioctylamine and methyl isobutyl ketone which can implement a cost-saving effect and the like, more preferably trioctylamine.

Commercially available extractants Alamine 336 or Aliquat 336, which is a nitrogen-based extractant (containing trioctylamine), or Cyanex 923, which is a phosphorus-based extractant (containing trialkylphosphine oxide), may be used alone or in addition. have.

The amount of the extractant is 40 moles or more, specifically 40 moles to 60 moles, more specifically 40 moles to 50 moles, and more specifically 40 moles based on 1 mole of iron (Fe) ions in the metal components included in the spent hydrochloric acid Moles to 45 moles.

When the amount of the extractant is less than 40 moles, the effect of removing metal components, particularly iron (Fe) ions, may be insignificant. In addition, when the amount of the extractant exceeds 60 moles, the effect of removing the metal components, particularly iron (Fe) ions component is not significantly different, but the manufacturing cost may increase because a large amount of the extractant is used. Therefore, considering the proper manufacturing cost and the efficiency of iron (Fe) ion component removal, it can be used in less than 60 moles.

1 and 2, in the hydrochloric acid purification method of the present invention, the waste hydrochloric acid is added to a reaction vessel, and then, an extraction solution is added and the metal component contained in the waste hydrochloric acid is extracted with an organic solvent while stirring. It can be carried out (S2).

In this case, the metal component included in the spent hydrochloric acid mainly contains iron ions, and in addition to the metal components, such as Al ³⁺ , Ca ²⁺ , K ⁺ , Mg ²⁺ , Ni ²⁺ may be further included. .

In addition, the hydrochloric acid: the extraction solution may be mixed in a 1: 0.1 to 1: 1 volume ratio, specifically 1: 1 volume ratio. If the extraction solution is added in less than 0.1 volume ratio (1/10) with respect to the waste hydrochloric acid, there is a disadvantage in that an emulsion occurs in the waste hydrochloric acid layer and thus phase separation is impossible. In addition, when the extraction solution is added in more than 1 volume ratio, there is a disadvantage that the process cost increases.

The extraction step (S2) may be carried out for 10 seconds to 60 seconds, specifically 20 seconds to 60 seconds while stirring the mixed solution of the hydrochloric acid and the extraction solution at a speed of 200 rpm to 600 rpm at an atmospheric temperature.

At this time, the room temperature is the average temperature or the temperature in the atmosphere throughout the year, specifically, means a temperature of 20 ± 5 ℃ range.

When the stirring speed is less than 200 rpm, the mixing is not smooth, there is a disadvantage in that the extraction efficiency of the metal component or the iron ion component is reduced. In addition, when the stirring speed exceeds 600 rpm, the metal component extraction effect is insignificant while the energy consumption may increase.

In addition, when the stirring time is less than 10 seconds, there is a disadvantage that the sufficient time for extracting the metal is not secured, and the metal component extraction efficiency is reduced. On the other hand, even if the stirring time exceeds 60 seconds, the amount of the extracted metal component does not show a big difference, but the process time and cost increases because the amount of waste hydrochloric acid that can be processed in the process is limited.

Various stirring apparatuses may be used for the stirring step, and as a representative example, the stirring step may be performed using a magnetic bar stirring plate or a static mixer.

On the other hand, in the extraction step (S2) of the method of the present invention, not only the metal component contained in the waste hydrochloric acid, specifically the iron (Fe) ion component, but also the yellow component FeCl ₄ ^- and FeCl ₃ are removed together (below) See Scheme 4), the high purity hydrochloric acid obtained after purification can be seen that the color is transparent (see Figure 3)

Scheme 4

R ₃ N (organic phase) + HCl (waste hydrochloric acid) → R ₃ NHCl (organic phase)

FeCl ₄ ^- (aqueous) + R ₃ NHCl (organic phase) → FeCl ₃ R ₃ NHCl (organic phase) + Cl ^- (aqueous)

FeCl ₃ (water layer) + R ₃ NHCl (organic phase) → FeCl ₃ R ₃ NHCl (organic phase)

Next, referring to FIGS. 1 and 2, in the method for purifying waste hydrochloric acid of the present invention, after stirring reaches an equilibrium, the mixed solution of the organic solvent and waste hydrochloric acid is placed in a separator, shaken, and left to stand. Phase separation (fractionation) of the organic solvent containing the component and the waste hydrochloric acid layer as an extract phase (S3).

At this time, the mixing step for the phase separation may be carried out within 20 seconds.

Subsequently, referring to FIGS. 1 and 2, in the hydrochloric acid purification method of the present invention, purified hydrochloric acid may be obtained by recovering the waste hydrochloric acid layer which is an phase separated from the phase separation step (S3) and is located at the bottom (S4). ).

In this case, the purified hydrochloric acid may effectively remove the metal component, particularly the iron (Fe) ion component, the iron (Fe) ion component may remain at a concentration of 1 ppm or less, specifically 0.1 ppm or less.

In addition, referring to Figure 2, the waste hydrochloric acid purification method of the present invention may further comprise the step of purifying the organic solvent used in the waste hydrochloric acid, in order to increase the regeneration efficiency of the organic solvent used in the waste hydrochloric acid purification. .

That is, the waste hydrochloric acid purification method of the present invention after the purified hydrochloric acid obtaining step (S4),

Removing residual metal components in the organic solvent by adding distilled water to the organic solvent containing the metal components separated in the phase separation step (S3) (S5);

Phase separating (fractionating) the stripped organic solvent and the water layer (S6); And

Recovering the phase-separated organic solvent and the water layer, respectively (S7); may further include.

That is, in the method of the present invention, the organic solvent recovered by phase separation after waste hydrochloric acid purification may be added to the reactor once again, and then distilled water may be added to remove metal components remaining in the organic solvent (S5).

By the stripping step, the residual metal component in the organic solvent can be extracted with water.

At this time, the organic solvent: distilled water may be mixed in a volume ratio of 1: 0.1 to 1: 1, specifically 1: 1 volume ratio. If the distilled water is less than 0.1, the extraction effect of the metal component is reduced, and when the distilled water is added in more than 1 volume ratio (1/1), the emulsion may occur and phase separation may not occur.

The stripping step (S5) may be performed for 10 seconds to 60 seconds, specifically 20 seconds to 60 seconds while stirring the mixed solution of the separated organic solvent and distilled water at a speed of 200 rpm to 600 rpm at room temperature.

At this time, the room temperature is the average temperature or the temperature in the atmosphere throughout the year, specifically, means a temperature of 20 ± 5 ℃ range.

If the stirring speed is less than 200 rpm, the mixing is not smooth, there is a disadvantage in that the extraction efficiency of the metal component is reduced. In addition, when the stirring speed exceeds 600 rpm, the metal component extraction effect is insignificant while the energy consumption may be increased.

If the stirring time for the stripping is less than 20 seconds, there is a disadvantage in that sufficient time for extracting the metal is not secured, thereby reducing the extraction efficiency of the metal component. On the other hand, even if the stirring time exceeds 60 seconds, the amount of the extracted metal component does not show a big difference, but the process time and cost increases because the amount of waste organic solvent that can be processed in the process is limited.

The stripping step (S5) may be used a variety of mixing device, as a representative example may use a magnetic bar stirring plate or a static mixer.

Next, referring to FIG. 2, in the method of the present invention, after stirring reaches an equilibrium, the organic solvent and the organic solvent in which the metal component is removed by stirring by stirring the mixed solution of the organic solvent and the distilled water layer in a separator, and iron, Phase separation (fractionation) was carried out with a distilled water layer containing the (Fe) ion component and the like (S6).

At this time, the phase separation step may be carried out within 20 seconds.

Subsequently, in the method of the present invention, the distilled water layer, which is the phase separated and the extracted phase located at the bottom, is removed, and the organic layer located at the top is recovered (S7), thereby effectively regenerating the organic phase used for waste hydrochloric acid purification.

At this time, by measuring the concentration of the residual metal contained in the recovered organic solvent and the water layer, it is possible to determine the degree of regeneration efficiency of the organic solvent according to the present invention.

As described above, in the case of the waste hydrochloric acid purification method using the solvent extraction method according to the method of the present invention, since iron (Fe) ion component can be effectively removed from the waste hydrochloric acid, the energy and cost saving effect according to the process simplification Can be imported. In addition, the method of the present invention further comprises the step of regenerating the organic solvent used in the waste hydrochloric acid purification method, it is possible to repeat the use of the organic solvent several times, significantly reducing the process operating costs and the like compared to the existing process can do.

Example

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Example 1.

The concentration of iron (Fe) ions contained in 100 ml of waste hydrochloric acid was measured by an inductively coupled plasma mass spectrometry (S0).

Subsequently, an extraction solution was prepared by dissolving trioctylamine (an iron (Fe) ion component included in waste hydrochloric acid: extractant = 1 mol: 40 mol) in 100 ml of an organic solvent toluene (S1).

Next, the extraction solution was added to 100 ml of waste hydrochloric acid, and metal components contained in the waste hydrochloric acid were extracted with an organic solvent while stirring at room temperature for 60 seconds at a speed of 200 rpm (S2).

After stirring reached equilibrium, the mixed solution of organic solvent and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a waste hydrochloric acid layer (S3).

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (S4) (see FIG. 3).

The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

At this time, the residual metal concentration was measured using Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-OES), and the total organic carbon (TOC) component was analyzed by a TOC analyzer (analyzer).

Example 2.

Purified hydrochloric acid was obtained in the same manner as in Example 1 except for using the extracting agent in a Fe: extractant = 1: 60 molar ratio included in the waste hydrochloric acid in the step (S1) of Example 1. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 1 below.

Example 3.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that cyclohexane was used instead of toluene in Example 1. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 4.

The hydrochloric acid purified in the same manner as in Example 3 was obtained except that the waste hydrochloric acid layer separated in Example 3 was extracted once more using cyclohexane in which 40 moles of the extractant was dissolved (S2). The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 5.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that xylene was used instead of toluene in Example 1. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 6.

The hydrochloric acid purified in the same manner as in Example 1 was obtained except that the waste hydrochloric acid layer separated in Example 5 was extracted once more using xylene in which 40 moles of the extractant was dissolved (S2). The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 7.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that in Example 1, a mixed solution of octane and 2-ethyl hexanol (1: 1 volume ratio) was used instead of toluene. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 8.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that in Example 1, a mixed solution of decane and 2-ethyl hexanol (1: 1 volume ratio) was used instead of toluene. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 9.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that a mixed solution (1: 1 volume ratio) of dodecane and 2-ethyl hexanol was used instead of toluene in Example 1. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 10.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that a mixed solution of kerosene and 2-ethyl hexanol (1: 1 volume ratio) was used instead of toluene in Example 1. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example 11.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that in Example 1, a mixed solution of kerosene and 2-dodecanol (1: 1 by volume) was used instead of toluene. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example  12.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that in the step (S1) of Example 1, an extraction solution was prepared by dissolving trialkylphosphine oxide instead of trioctylamine as an extractant. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example  13.

Purified hydrochloric acid was obtained in the same manner as in Example 3, except that in the step (S1) of Example 3, an extraction solution was prepared by dissolving trialkylphosphine oxide instead of trioctylamine as an extractant. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Example  14.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that methyl cyclohexane was used instead of toluene when preparing the extraction solution in the step (S1) of Example 1. The residual metal concentration and TOC in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

Comparative Example 1.

10 wt% of an ion exchange resin (IRA-900) was injected into 100 ml of waste hydrochloric acid, and stirred at room temperature for 1 hour at a speed of 200 rpm. The reaction was then filtered to remove the ion exchange resin and to obtain purified hydrochloric acid.

The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 1 below.

Comparative Example 2.

Purified hydrochloric acid was obtained in the same manner as in Comparative Example 1 except for using the ion exchange resin (IRA-910) instead of the ion exchange resin (IRA-900) in Comparative Example 1. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 1 below.

Comparative Example 3.

To remove free residual hydrochloric acid in 100 ml of waste hydrochloric acid, NaSO ₃ was added, stirred at room temperature for 1 hour at a speed of 200 rpm, and then 10% by weight of an ion exchange resin (IRA-910) was injected into the mixture, and 200 rpm. Stirred at room temperature for 1 hour at a rate of.

The reaction was then filtered to remove the ion exchange resin and to obtain purified hydrochloric acid. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 1 below.

Comparative Example 4.

20% by weight of activated carbon was added to 100 ml of waste hydrochloric acid and stirred at room temperature for 1 hour at a speed of 200 rpm, and then the reaction product was filtered to remove activated carbon.

10 wt% of an ion exchange resin (IRA-910) was injected into 100 ml of waste hydrochloric acid obtained by the filtration process, and stirred at room temperature for 1 hour at a speed of 200 rpm.

The reaction was then filtered to remove the ion exchange resin and to obtain purified hydrochloric acid.

The residual metal concentration and TOC in the obtained hydrochloric acid in the purified hydrochloric acid were measured, and the results are shown in Tables 1 and 2 below.

	Extraction solution		Al	Ca	Fe	K	Mg
	Extractant	Organic solvent
Waste hydrochloric acid	-	-	5	15	20	5	5
Example 1	Trioctylamine	toluene	6	16	<0.1	5	5
Example 2	Trioctylamine	toluene	6	17	<0.1	5	5
Example 3	Trioctylamine	Cyclohexane	5	16	<0.1	5	5
Example 4	Trioctylamine	Cyclohexane (twice)	5	16	<0.1	5	5
Example 5	Trioctylamine	xylene	6	16	<0.1	5	5
Example 6	Trioctylamine	Xylene (2 times)	6	17	<0.1	5	5
Example 7	Trioctylamine	Octane + 2-ethyl hexanol	7	17	<0.1	5	5
Example 8	Trioctylamine	Decane + 2-ethyl hexanol	7	16	<0.1	5	5
Example 9	Trioctylamine	Dodecane + 2-ethyl hexanol	7	16	<0.1	5	5
Example 10	Trioctylamine	Kerosene + 2-ethyl hexanol	7	17	<0.1	6	5
Example 11	Trioctylamine	Kerosene + 2-dodecanol	6	16	One	5	5
Example 12	Trialkylphosphine oxide	toluene	3	16	<0.1	3	4
Example 13	Trialkylphosphine oxide	Cyclohexane	4	16	<0.1	4	5
Example 14	Trioctylamine	Methyl cyclohexane	2	8	<0.1	3	2
Comparative Example 1	-	-	4	16	4	4	5
Comparative Example 2	-	-	4	16	4	4	5
Comparative Example 3	-	-	4	18	4	4	6
Comparative Example 4	-	-	N.D	N.D	21	N.D	N.D

* Metal concentration unit (ppm)

As shown in Table 1, in Examples 1 to 14 using the solvent extraction method of the present invention, the concentration of the residual iron (Fe) ion component is 1 ppm or less (95% or more removed) regardless of the type of the organic solvent. You can see that.

Furthermore, during the purification process, FeCl ₄ ⁻ and FeCl ₃ , which are yellow components of the spent hydrochloric acid, were removed together to confirm that the color of the spent hydrochloric acid became transparent after purification (see FIG. 3).

On the other hand, in Comparative Examples 1 to 3 using ion exchange resins to remove iron (Fe) ions in the waste hydrochloric acid, the concentration of residual iron (Fe) ions is 1 ppm or more (about 80%). You can see that. In particular, in the case of Comparative Example 3 in which NaSO ₃ was added to remove free residual chlorine, it was confirmed that the Fe removal efficiency is not affected.

In addition, in the case of the method of Comparative Example 4 using the ion exchange resin after the activated carbon treatment, it was confirmed that the concentration of Fe increased rather than Comparative Examples 1 and 2. These results can be predicted to include excess metal impurities from activated carbon emissions.

	Extraction solution		TOC (total organic carbon)	TIC (total inorganic carbon)	TC (total carbon)
	Extractant	Organic solvent
Waste hydrochloric acid	-	-	67.65	54.64	122.29
Example 1	Trioctylamine	toluene	5.22	64.18	69.4
Example 3	Trioctylamine	Cyclohexane	37.1	54.17	91.27
Example 4	Trioctylamine	Cyclohexane (twice)	14.27	53.85	68.12
Example 5	Trioctylamine	xylene	40.7	54.4	95.1
Example 6	Trioctylamine	Xylene (2 times)	6.28	63.7	69.98
Example 7	Trioctylamine	Octane + 2-ethyl hexanol	45.93	54.84	100.77
Example 8	Trioctylamine	Decane + 2-ethyl hexanol	65.48	140.56	206.04
Example 9	Trioctylamine	Dodecane + 2-ethyl hexanol	66.15	145.06	211.21
Example 10	Trioctylamine	Kerosene + 2-ethyl hexanol	59.51	144.24	203.85
Example 11		Kerosene + 2-dodecanol	53.51	55.05	108.56
Example 14	Trioctylamine	Methyl cyclohexane	53.58	151.7	205.28
Comparative Example 4	-	-	18.79	54.78	73.57

In addition, as shown in Table 2, when comparing the TOC value of the purified hydrochloric acid recovered after extraction, the value when using toluene in the extraction solution was 5.22, showing the lowest TOC content. From these results, it can be seen that when toluene is used, phase separation is most effective, and organic impurities are not included in the waste hydrochloric acid after phase separation.

Example 15.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that 50 ml of the organic solvent was used instead of 100 ml in Example 1. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 3 below.

Example 16.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that 30 ml of the organic solvent was used instead of 100 ml in Example 1. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 3 below.

Example 17.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that 10 ml of the organic solvent was used instead of 100 ml in Example 1. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 3 below.

Comparative example  5.

When using 9 ml instead of 100 ml of the organic solvent in Example 1, while the emulsion (emulsion) occurs in the waste hydrochloric acid layer, phase separation was not easy.

	Organic Solvent Content (ml)	Al	Ca	Fe	K	Mg
Waste hydrochloric acid	-	5	15	20	5	5
Example 15	50	4	16	<0.1	4	5
Example 16	30	4	16	<0.1	4	5
Example 17	10	4	16	<0.1	4	5
Comparative Example 5	9	-	-	-	-	-

As can be seen from Table 3, as a result of measuring the concentration change of the iron (Fe) ions while changing the mixing ratio of the extraction solution and the waste hydrochloric acid, Fe removal even if the amount of the organic solvent in the extraction solution decreases It can be seen that the efficiency does not decrease.

On the other hand, when the mixing ratio of the organic solvent / waste hydrochloric acid is less than 1/10 as in Comparative Example 5, an emulsion phenomenon occurs, it was confirmed that it is difficult to purify pure hydrochloric acid because the phase separation itself is difficult.

Example 18.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the extraction time by stirring the organic solvent and the spent hydrochloric acid in Example 1 was performed at 50 seconds. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 4 below.

Example 19.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the extraction time by stirring the organic solvent and the spent hydrochloric acid in Example 1 was performed for 30 seconds. The concentration of iron (Fe) ions in the purified hydrochloric acid was measured, and the results are shown in Table 4 below.

Example 20.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the extraction time by stirring the organic solvent and the spent hydrochloric acid in Example 1 was performed for 20 seconds. The concentration of iron (Fe) ions in the purified hydrochloric acid was measured, and the results are shown in Table 4 below.

Example 21.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the extraction time by stirring the organic solvent and the spent hydrochloric acid in Example 1 was performed for 10 seconds. The concentration of iron (Fe) ions in the purified hydrochloric acid was measured, and the results are shown in Table 4 below.

	Agitation time (seconds)	Fe
Waste hydrochloric acid	-	20
Example 18	50	<0.1
Example 19	30	<0.1
Example 20	20	<0.1
Example 21	10	0.1

As can be seen from Table 4, as a result of measuring the concentration change of the iron (Fe) ions while changing the mixing time of the organic solvent and waste hydrochloric acid, Fe removal efficiency in the waste hydrochloric acid even if the extraction time is reduced to 20 seconds It can be seen that this is excellent.

However, when the extraction time is 10 seconds, the Fe removal efficiency is reduced, it can be seen that less than 1 ppm of Fe is detected.

Example 22.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the stirring speed of the organic solvent and the hydrochloric acid for extraction in Example 1 was performed at 600 rpm instead of 200 rpm. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 5 below.

Example 23.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the stirring speed of the organic solvent and the hydrochloric acid for extraction in Example 1 was performed at 300 rpm instead of 200 rpm. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 5 below.

Example 24.

Purified hydrochloric acid was obtained in the same manner as in Example 1, except that the stirring speed of the organic solvent and the hydrochloric acid for extraction in Example 1 was performed at 100 rpm instead of 200 rpm. The residual metal concentration in the purified hydrochloric acid was measured and the results are shown in Table 5 below.

	Stirring Speed (rpm)	Al	Ca	Fe	K	Mg
Waste hydrochloric acid	-	5	15	20	5	5
Example 22	600	One	7	<0.1	2	2
Example 23	300	One	7	<0.1	2	2
Example 24	100	One	7	0.7	2	2

As can be seen from Table 5, as a result of experiments while lowering the stirring speed in the stirring process for extraction, intermixing is not smooth when stirring at a speed of 100 rpm lower than 200rpm, ICP measurement results of about 0.7 ppm of Fe It can be seen that is detected.

Example 25.

After measuring the concentration of iron (Fe) ions contained in 100 ml of waste hydrochloric acid, trioctylamine (Fe: extractant in waste hydrochloric acid = 1: 40 mol) was extracted in 100 ml of toluene, an organic solvent. An extraction solution was prepared (S1).

Subsequently, the extraction solution was added to 100 ml of hydrochloric acid, and the metal components contained in the hydrochloric acid were extracted with an organic solvent while stirring at room temperature for 60 seconds at a speed of 200 rpm (S2).

After stirring reached equilibrium, the mixed solution of organic solvent and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a waste hydrochloric acid layer (S3).

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (1) (S4).

Subsequently, 100 ml of distilled water was added to the separated organic solvent, and the remaining metal component was removed from the organic solvent while stirring at room temperature for 1 hour at a speed of 200 rpm (S5).

After completion of the stirring, the mixed solution of the organic solvent (1) and the water layer removed in the separator was phase-separated for about 20 seconds, to separate the organic solvent and the water layer (S6). The separated water layer 1 was recovered (S7).

The residual metal concentration in the purified hydrochloric acid (1) and the water layer (1) was measured, and the results are shown in Table 6 below.

Example 26.

The organic solvent (1) recovered by phase separation from the waste hydrochloric acid layer of Example 25 was re-injected into 100 ml of waste hydrochloric acid, and the organic solvent was mixed with the metal components contained in the waste hydrochloric acid while stirring at room temperature for 1 hour at a speed of 200 rpm. Extracted with (S2-2).

After stirring reached equilibrium, the mixed solution of the re-injected organic solvent (1) and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a waste hydrochloric acid layer. (S3-2).

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (2) (S4-2).

Subsequently, 100 ml of distilled water was added to the phase-separated organic solvent, and the remaining metal component in the organic solvent was removed again while stirring at room temperature for 1 hour at a speed of 200 rpm (S5-2).

After completion of the stirring, the mixed solution of the organic solvent (2) and the water layer removed in the separator was phase-separated for about 20 seconds, the organic solvent and the water layer was phase-separated (S6-2). The phase separated water layer 2 was recovered (S7-2).

The residual metal concentration in the purified hydrochloric acid (2) and the water layer (2) was measured, and the results are shown in Table 6 below.

Example 27.

The organic solvent (2) recovered by phase separation from the waste hydrochloric acid layer of Example 26 was recycled to 100 ml of waste hydrochloric acid, and the metal components contained in the waste hydrochloric acid were stirred at room temperature for 1 hour at 200 rpm. Extracted with (S2-3).

After stirring reached equilibrium, the mixed solution of the re-injected organic solvent and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a waste hydrochloric acid layer (S3-). 3)

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (3) (S4-3).

Subsequently, 100 ml of distilled water was added to the phase-separated organic solvent, and the remaining metal component was removed from the organic solvent while stirring at room temperature for 1 hour at a speed of 200 rpm (S5-3).

After completion of the stirring, the mixed solution of the organic solvent (3) and the water layer removed in the separator was phase-separated for about 20 seconds, to separate the organic solvent and the water layer (S6-3). The separated water layer 3 was recovered (S7-3).

The residual metal concentration in the purified hydrochloric acid (3) and the water layer (3) was measured, and the results are shown in Table 6 below.

Example 28.

The organic solvent (3) recovered by phase separation from the waste hydrochloric acid layer of Example 27 was re-injected into 100 ml of waste hydrochloric acid, and the metal components contained in the waste hydrochloric acid were stirred at room temperature for 1 hour at 200 rpm. Extracted with (S2-4).

After stirring reached equilibrium, the mixed solution of the re-injected organic solvent and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a phosphorus hydrochloric acid (S3-). 4).

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (4) (S4-4).

Subsequently, 100 ml of distilled water was added to the phase-separated organic solvent, and the residual metal component of the organic solvent was removed while stirring at room temperature for 1 hour at a speed of 200 rpm (S5-4).

After completion of the stirring, the mixed solution of the stripped organic solvent 4 and the water layer was put in a separator and phase separated for about 20 seconds to separate the organic solvent and the water layer (S6-4). The separated water layer 4 was recovered (S7-4).

The residual metal concentration in the purified hydrochloric acid (4) and the water layer (4) was measured, and the results are shown in Table 6 below.

	Extraction count	Al	Ca	Fe	K	Mg
Waste hydrochloric acid	-	5	15	20	5	5
Example 25	Purified hydrochloric acid (1)	4	16	<0.1	4	5
	Water Layers (1)	0.6	0.2	20	0.3	<0.1
Example 26	Purified hydrochloric acid (2)	4	16	<0.1	4	5
	Water Layers (2)	0.5	0.2	21	0.2	<0.1
Example 27	Purified hydrochloric acid (3)	4	16	<0.1	4	5
	Water Layers (3)	0.5	0.2	21	0.2	<0.1
Example 28	Purified hydrochloric acid (4)	4	16	<0.1	4	5
	Water Layers (4)	0.5	0.2	21	0.2	<0.1

As shown in Table 6, as a result of repeating the waste hydrochloric acid purification process several times using the removed organic solvent, it can be seen that the iron (Fe) ion component in the waste hydrochloric acid is constantly removed to 0.1 ppm or less.

That is, even when the organic solvent was purified and used in the hydrochloric acid purification step (metal component extraction step) as many times as in Examples 26 to 28, it can be seen that there is no significant difference from the waste hydrochloric acid purification effect of Example 25. Therefore, in the case of the waste hydrochloric acid purification method of the present invention it can be confirmed that the organic solvent can be effectively recycled.

Example 29.

After measuring the concentration of iron (Fe) ions contained in 100 ml of waste hydrochloric acid, trialkylphosphine oxide (Fe: extractant in waste hydrochloric acid = 1: 40 mol) was extracted in 100 ml of toluene, an organic solvent. It was dissolved to prepare an extraction solution (S'1).

Subsequently, the extraction solution was added to 100 ml of waste hydrochloric acid, and metal components contained in the waste hydrochloric acid were extracted with an organic solvent while stirring at room temperature for 60 seconds at a speed of 200 rpm (S'2).

After stirring reached equilibrium, the mixed solution of organic solvent and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a waste hydrochloric acid layer (S'3). ).

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (1) (S'4).

Subsequently, 100 ml of distilled water was added to the separated organic solvent, and the remaining metal component was removed from the organic solvent while stirring at room temperature for 1 hour at a speed of 200 rpm (S'5).

After the stirring was completed, the mixed solution of the organic solvent and the water layer was put in a separator and phase separated for about 20 seconds, and the organic solvent and the water layer were fractionated (S'6). The separated water layer 1 was recovered (S'7).

The residual metal concentration in the purified organic solvent and the water layer 1 was measured, and the results are shown in Table 7 below.

Example 30.

After measuring the concentration of iron (Fe) ions contained in 100 ml of waste hydrochloric acid, trialkylphosphine oxide as an extractant in 100 ml of organic solvent cyclohexane (Fe: extractant in waste hydrochloric acid = 1: 40 mol) Was dissolved to prepare an extraction solution (S'1).

Subsequently, the extraction solution was added to 100 ml of waste hydrochloric acid, and metal components contained in the waste hydrochloric acid were extracted with an organic solvent while stirring at room temperature for 60 seconds at a speed of 200 rpm (S'2).

After stirring reached equilibrium, the mixed solution of organic solvent and waste hydrochloric acid was placed in a separator, shaken for about 20 seconds, and allowed to stand for phase separation (fractionation) into an organic solvent containing a metal component and a waste hydrochloric acid layer (S'3). ).

Subsequently, the separated hydrochloric acid layer was recovered to obtain purified hydrochloric acid (1) (S'4).

Subsequently, 100 ml of distilled water was added to the separated organic solvent, and the remaining metal component was removed from the organic solvent while stirring at room temperature for 1 hour at a speed of 200 rpm (S'5).

After the stirring was completed, the mixed solution of the organic solvent and the water layer was put in a separator and phase separated for about 20 seconds, and the organic solvent and the water layer were fractionated (S'6). The separated water layer 1 was recovered (S'7).

The residual metal concentration in the purified organic solvent and the water layer 1 was measured, and the results are shown in Table 7 below.

	Extraction count	Al	Ca	Fe	K	Mg
Waste hydrochloric acid	-	5	15	20	5	5
Example 29	Organic solvent layer	One	<0.1	9	One	One
	Water Layers (1)	0.4	0.2	11	0.3	<0.1
Example 30	Organic solvent layer	<0.1	<0.1	12	<0.1	<0.1
	Water Layers (1)	0.4	0.1	8	0.2	<0.1

As shown in Table 7, as a result of performing the hydrochloric acid purification and the organic solvent stripping process using trialkylphosphine oxide as an extractant, as shown in Table 1, the metal components in the waste hydrochloric acid, in particular iron (Fe) While the ionic component is removed to 1 ppm or less, it can be seen that there is a limitation in reusing the organic solvent because stripping is not effectively performed in the organic solvent layer.

Claims (15)

1. Dissolving the extractant in an organic solvent to prepare an extraction solution (S1);

   Injecting the extraction solution into the waste hydrochloric acid to extract the metal component in the waste hydrochloric acid with an organic solvent (S2);

   Phase-separating the organic solvent containing the metal component and the waste hydrochloric acid layer (S3); And

   Recovering the phase separation (fractionated) hydrochloric acid layer to obtain purified hydrochloric acid (S4); and

   The amount of the extractant is 40 mol or more based on 1 mol of iron (Fe) ions among the metal components contained in the waste hydrochloric acid,

   The waste hydrochloric acid: extraction solution is a waste hydrochloric acid purification method that is mixed in a 1: 0.1 to 1: 1 volume ratio.
2. The method according to claim 1,

   The waste hydrochloric acid purification method further comprises the step (S0) of measuring the concentration of the iron (Fe) ion component in the metal component contained in the waste hydrochloric acid before preparing the extraction solution.
3. The method according to claim 1,

   The organic solvent is a hydrochloric acid purification method comprising at least one solvent selected from the group consisting of an aromatic hydrocarbon solvent, an aliphatic hydrocarbon solvent and an alcohol.
4. The method according to claim 3,

   The aromatic hydrocarbon solvent comprises at least one selected from the group consisting of toluene, and xylene,

   The aliphatic hydrocarbon solvent includes at least one alicyclic hydrocarbon solvent selected from the group consisting of methyl cyclohexane and cyclohexane, or a linear hydrocarbon solvent having 6 to 20 carbon atoms,

   The alcohol is a hydrochloric acid purification method comprising a monohydric alcohol having 6 to 20 carbon atoms.
5. The method according to claim 1,

   Wherein said extracting agent is at least one selected from the group consisting of trioctylamine, methyl isobutyl ketone, trialkylphosphine oxide and tributyl phosphate.
6. The method according to claim 5,

   The extracting agent is at least one selected from the group consisting of trioctylamine and methyl isobutyl ketone waste hydrochloric acid purification method.
7. The method according to claim 6,

   The extracting agent is trioctylamine waste hydrochloric acid purification method.
8. The method according to claim 1,

   The amount of the extractant is 40 to 60 moles based on 1 mole of iron (Fe) ionic component will waste hydrochloric acid purification method.
9. The method according to claim 8,

   The amount of the extractant is 40 to 50 moles based on 1 mole of iron (Fe) ionic component will waste hydrochloric acid purification method.
10. The method according to claim 1,

    The extraction step (S2) is a waste hydrochloric acid purification method that is carried out at room temperature for 20 seconds to 60 seconds while stirring the mixed solution of waste hydrochloric acid and the extraction solution at a speed of 200 rpm to 600 rpm.
11. The method according to claim 1,

    The phase separation step (S3) is a hydrochloric acid purification method that is carried out within 20 seconds.
12. The method according to claim 1,

    The method after the purified hydrochloric acid step (S4),

    Removing distilled water from the organic solvent containing the separated metal component to remove residual metal components from the organic solvent (S5);

    Phase separating the stripped organic solvent and the water layer (S6); And

    Recovering the phase separated organic solvent and the water layer, respectively (S7); Waste hydrochloric acid purification method further comprising.
13. The method according to claim 12,

    The organic solvent: distilled water is a waste hydrochloric acid purification method of mixing in a volume ratio of 1: 1.
14. The method according to claim 12,

    The stripping step (S5) is a waste hydrochloric acid purification method that is carried out at room temperature for 20 seconds to 60 seconds while stirring the mixed solution of the separated organic solvent and distilled water at a speed of 200 rpm to 600 rpm.
15. The method according to claim 12,

    The phase separation step (S6) is a hydrochloric acid purification method that is carried out within 20 seconds.

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