CN115089999B - Application of a composite extractant in recycling waste acid in chemical polishing liquid of waste aluminum - Google Patents

Abstract

The present invention discloses an application of a composite extractant in the recovery of waste acid in a chemical polishing liquid for waste aluminum. The composite extractant of the present invention is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is (6-9): (1-4). When applied to the chemical polishing liquid for waste aluminum, P=O in tributyl phosphate and C-OH in n-butanol can form hydrogen bonds with the protons of the waste acid in the chemical polishing liquid for waste aluminum, so that the waste acid molecules in the chemical polishing liquid for waste aluminum are extracted into an organic phase, thereby efficiently recovering the waste acid; at the same time, by regulating the volume ratio of tributyl phosphate to n-butanol, the waste acid is effectively separated from the impurity aluminum ions, so that the waste acid recovered by extraction can be recycled for use in the chemical polishing liquid for aluminum.

Description

Application of a composite extractant in recycling waste acid in chemical polishing liquid of waste aluminum

Technical Field

The invention relates to the field of extraction technology, and more specifically to application of a composite extractant in recycling waste acid in chemical polishing liquid for waste aluminum materials.

Background technique

Aluminum and its alloys are excellent metal materials that are widely used in modern society for their bright metallic luster and corrosion resistance. In daily necessities, aluminum and its alloys need to be surface polished to meet the needs of aesthetics or further corrosion protection. During use, as hydrogen ions are consumed, metal parts gradually dissolve, and the concentration of metal ions in the chemical polishing liquid continues to increase, which leads to a gradual deterioration of the polishing effect and the failure of the aluminum chemical polishing liquid. Moreover, the aluminum chemical polishing liquid contains high concentrations of H ₃ PO ₄ , H ₂ SO ₄ and Al ³⁺ , etc., which have been listed in the national hazardous waste list (HW17) and seriously affect the ecological environment, and cannot be directly discharged.

In order to avoid the impact of chemical polishing liquid of waste aluminum on the ecological environment, the traditional treatment method is to treat it as waste, that is, adding alkaline substances or metal ions that can precipitate with waste acid, and converting it into relatively safe solid residue after solid-liquid separation. However, this treatment method cannot achieve the recovery of waste acid in chemical polishing liquid of waste aluminum.

In the prior art, an extraction method is often used to recover waste acid from waste liquid. For example, the prior art discloses a method for recovering electroplating phosphoric acid waste liquid, in which tributyl phosphate is used as an extractant to extract and recover phosphoric acid from the phosphoric acid waste liquid, while reducing the iron and aluminum contents in the phosphoric acid waste liquid. However, this treatment method is only aimed at the separation and recovery of single phosphoric acid and aluminum, and cannot achieve the separation and recovery of _H3PO4 and _Al3 ⁺ when _H2SO4 exists at the same _time .

Summary of the invention

The purpose of the present invention is to overcome the defects and shortcomings of existing extractants that it is difficult to effectively separate high- _{concentration H3PO4 and H2SO4} from impurity Al3 ⁺ in aluminum chemical waste polishing liquid at the same time, and provide an application of a composite extractant in recovering waste acid in waste aluminum chemical polishing liquid. The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is (6-9): (1-4), which can achieve the recovery of high-concentration residual acid in aluminum chemical waste polishing liquid and remove impurity aluminum ions therein.

Another object of the present invention is to provide an aluminum material chemical polishing solution.

The above-mentioned purpose of the present invention is achieved through the following technical solutions:

The invention discloses an application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials. The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of the tributyl phosphate to n-butanol is (6-9):(1-4).

The composite extractant of the invention consists of tributyl phosphate and n-butanol, wherein P=O in _tributyl phosphate can form hydrogen bonds with protons in _H3PO4 and _H2SO4 , and C-OH in n-butanol can also form hydrogen bonds with protons in _H3PO4 and _H2SO4 , that is, _{the composite extractant extracts H3PO4 and H2SO4 in waste liquid} into _an organic phase through hydrogen bonding, and the presence _{of H2SO4 can} also inhibit _{the dissociation of H3PO4 , thereby improving} the extraction effect of phosphoric acid.

Moreover, the composite extractant of the present invention can effectively increase β(H ₃ PO ₄ /Al ³⁺ ) and β(H ₂ SO ₄ /Al ³⁺ ) simultaneously by adding n-butanol to tributyl phosphate, thereby realizing effective separation of H ₃ PO ₄ , H ₂ SO ₄ and Al ³⁺ . The solubility of n-butanol in water is higher than that of tributyl phosphate in water, and n-butanol dissolved in water will bring impurity aluminum ions in the waste liquid into the organic phase. During the stripping process, H ₃ PO ₄ and H ₂ SO ₄ in the organic phase enter the aqueous phase, and the impurity aluminum ions enter the stripping solution along with H ₃ PO ₄ and H ₂ SO ₄ . Therefore, when the content of n-butanol in the composite extractant is too high, the separation effect of H ₃ PO ₄ and H ₂ SO ₄ from impurity aluminum ions will be poor; and when the content of n-butanol in the composite extractant of the present invention is too low, the extraction effect of H ₃ PO ₄ and H ₂ SO ₄ by the composite extractant will be too poor, thereby affecting the recycling application of waste acid in aluminum chemical polishing liquid.

Preferably, the volume ratio of tributyl phosphate to n-butanol is (6-7):(3-4).

In a specific embodiment, the application of the composite extractant of the present invention in recovering waste acid in chemical polishing liquid of waste aluminum comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly, and the extraction phases are separated to obtain a loaded organic phase and a raffinate;

S2. The loaded organic phase and water in S1 are added to an extraction device and mixed thoroughly, and stripped to obtain an organic phase and a stripping solution;

Wherein, the stripping solution in S2 is a mixed solution of H ₃ PO ₄ and H ₂ SO ₄ .

Preferably, the volume ratio of the composite extractant to the chemical polishing liquid for waste aluminum in S1 is (1-4):1.

During the extraction process, with the increase of the amount of composite extractant added, H ₃ PO ₄ and H ₂ SO ₄ in the chemical polishing liquid of scrap aluminum are more easily extracted into the organic phase, thereby increasing the extraction rate of H ₃ PO ₄ and H ₂ SO ₄ ; but when the volume ratio of the composite extractant to the chemical polishing liquid of scrap aluminum is greater than 4:1, the extraction rates of H ₃ PO ₄ and H ₂ SO ₄ basically tend to be stable with the increase of the amount of composite extractant added.

Preferably, the volume ratio of the loaded organic phase to water in S2 is (2-7):1.

In the stripping process, H ₃ PO ₄ and H ₂ SO ₄ in the loaded organic phase are stripped to the water phase. By increasing the volume ratio of the loaded organic phase to water, the purpose of enriching and concentrating H ₃ PO ₄ and H ₂ SO ₄ can be achieved.

In a specific embodiment, the extraction temperature in step S1 of the present invention is 10-50°C, and the back extraction temperature in step S2 is 10-50°C.

In a specific implementation manner, the chemical polishing liquid for waste aluminum materials of the present invention includes H ₃ PO ₄ , H ₂ SO ₄ and Al ³⁺ .

Specifically, the solubility of H ₃ PO ₄ in the waste aluminum chemical polishing liquid is 373.96-378.73 g/L, the concentration of H ₂ SO ₄ is 246.67-268.56 g/L, and the concentration of Al ³⁺ is 24.54-25.95 g/L.

In a specific embodiment, the extraction level of the extraction in step S1 of the present invention is 1 to 8; the extraction level of the back extraction in step S2 is 1 to 8.

The present invention also protects an aluminum material chemical polishing solution prepared by using the stripping solution as a raw material.

Compared with the prior art, the present invention has the following beneficial effects:

The composite extractant of the invention consists of tributyl phosphate and n-butanol. When applied to the chemical polishing liquid of waste aluminum, P=O in the tributyl phosphate and C-OH in the n-butanol can form hydrogen bonds with protons in waste acid in the waste liquid, so that the waste acid molecules in the chemical polishing liquid of waste aluminum are extracted into the organic phase, thereby efficiently recovering the waste acid, the stripping rate of _H3PO4 reaches 94.5%-95.6%, and the stripping rate of _H2SO4 reaches 91.11%-92.38%. At the same time, by adjusting the volume ratio of _tributyl phosphate and n-butanol _, the waste acid and _impurity aluminum ions are effectively separated, β( _H3PO4 /Al3 ⁺ ) reaches 9.68-11.58, and β( _H2SO4 / ^Al3+ ₎ reaches 4.81-5.86, so that the waste acid recovered by extraction can be recycled for use in the chemical polishing liquid of aluminum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a schematic diagram of the application process of the composite extractant of the present invention in recovering waste acid in chemical polishing liquid of waste aluminum.

Detailed ways

The present invention is further described below in conjunction with specific embodiments, but the embodiments do not limit the present invention in any form. Unless otherwise specified, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

The extraction rate, stripping rate, separation coefficient and distribution ratio of the present invention are respectively determined by the following formulas. Stripping rate:/> Distribution ratio: /> Separation factor:/> C ₀ - concentration of each component in the scrap aluminum polishing liquid, mol/L; V ₀ - volume of the scrap aluminum polishing liquid, L;

C _aq - concentration of each component in the raffinate, mol/L; V _aq - volume of the raffinate, L;

C _org - concentration of each component in the loaded organic phase, mol/L; V _org - volume of the loaded organic phase, L;

C _s - concentration of each component in the aqueous phase after stripping, mol/L; V _s - volume of the aqueous phase after stripping, L.

Example 1

The application of a composite extractant in the recovery of waste acid in chemical polishing liquid of waste aluminum includes the following steps (as shown in FIG1 ):

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is 9:1. The main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ^{3 +} 24.90 g/L.

Example 2

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is 8:2. The main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ^{3 +} 24.90 g/L.

Example 3

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is 7:3. The main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ^{3 +} 24.90 g/L.

Example 4

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is 6:4. The main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ^{3 +} 24.90 g/L.

Example 5

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After 5-stage intermittent multi-stage countercurrent extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 2:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly, and subjected to two-stage intermittent multi-stage countercurrent extraction, and the organic phase and the stripping solution are obtained after phase separation, the volume ratio of the organic phase to the aqueous phase is 2:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, the volume ratio of tributyl phosphate to n-butanol is 7:3, and the main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 378.73 g/L, H ₂ SO ₄ 246.67 g/L, and Al ³⁺ 25.95 g/L.

The above raffinate and stripping solution were tested, and the obtained extraction rate and stripping rate are shown in Table 1.

Table 1

Components H ₃ PO _{4 H2SO4 ​} Al ³⁺ Extraction rate 70%-75% 52%-55% <10% Stripping rate 95.6% 92.38% /

Example 6

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly, and subjected to 4-stage intermittent multi-stage countercurrent extraction, and the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant and the chemical polishing liquid of the waste aluminum is 4:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly, and subjected to two-stage intermittent multi-stage countercurrent extraction, and the organic phase and the stripping solution are obtained after phase separation, the volume ratio of the organic phase to the aqueous phase is 5:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is 7:3; the main component contents of the waste aluminum chemical polishing liquid are H ₃ PO ₄ 377.48 g/L, H ₂ SO ₄ 260.56 g/L, and Al ³⁺ 24.54 g/L.

The above raffinate and stripping solution were tested, and the obtained extraction rate and stripping rate are shown in Table 2.

Table 2

Components H ₃ PO _{4 H2SO4 ​} Al ³⁺ Extraction rate 76%-79% 52%-55% <5% Stripping rate 94.5% 91.11% /

Comparative Example 1

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is 9.8:0.2. The main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ³⁺ 24.90 g/L.

Comparative Example 2

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-butanol, the volume ratio of tributyl phosphate to n-butanol is 1:1, and the main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ³⁺ 24.90 g/L.

Comparative Example 3

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and n-octanol, and the volume ratio of tributyl phosphate to n-octanol is 9:1. The main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ^{3 +} 24.90 g/L.

Comparative Example 4

The application of a composite extractant in recovering waste acid in chemical polishing liquid of waste aluminum materials comprises the following steps:

S1. The composite extractant and the chemical polishing liquid of the waste aluminum are added to the extraction device and mixed thoroughly. After primary extraction, the loaded organic phase and the raffinate are obtained after phase separation. The volume ratio of the composite extractant to the chemical polishing liquid of the waste aluminum is 1:1, the extraction temperature is 30°C, and the extraction time is 10min;

S2. The loaded organic phase and water described in S1 are added to the extraction device and mixed thoroughly. After primary extraction, the organic phase and the stripping solution are obtained after phase separation. The volume ratio of the organic phase to the aqueous phase is 1:1, the stripping temperature is 30°C, and the stripping time is 10 min;

The composite extractant is composed of tributyl phosphate and methyl isobutyl ketone, the volume ratio of tributyl phosphate to methyl isobutyl ketone is 9:1, and the main components of the chemical polishing liquid for waste aluminum are H ₃ PO ₄ 373.96 g/L, H ₂ SO ₄ 254.76 g/L, and Al ³⁺ 24.90 g/L.

Table 3 Separation coefficient (β) and distribution ratio (D) of each component in Examples 1 to 4 and Comparative Examples 1 to 4

serial number β(H ₃ PO ₄ /Al ³⁺ ) β(H ₂ SO ₄ /Al ³⁺ ) D(H ₃ PO ₄ ) D(H ₂ SO ₄ ) D(Al ³⁺ ) Example 1 9.81 5.17 0.3603 0.1898 0.0367 Example 2 9.68 4.81 0.3697 0.1838 0.0382 Example 3 11.58 5.86 0.3598 0.1820 0.0311 Example 4 10.64 5.04 0.3854 0.1826 0.0362 Comparative Example 1 7.71 4.06 0.3598 0.1895 0.0467 Comparative Example 2 9.07 5.36 0.3441 0.2036 0.0380 Comparative Example 3 8.13 4.26 0.3175 0.1662 0.0391 Comparative Example 4 9.35 4.26 0.3307 0.1506 0.0354

The distribution ratio (D) is the ratio of the total concentration of the extract in the organic phase to the total concentration in the aqueous phase after the extraction system reaches equilibrium. The higher the distribution ratio of phosphoric acid and sulfuric acid, the stronger the ability of the extractant to extract acid. The separation coefficient (β) is the ratio of the distribution ratios of the two substances during the extraction process. The larger the separation coefficient, the higher the degree of separation, indicating that H ₃ PO ₄ or H ₂ SO ₄ and Al ³⁺ are separated more thoroughly. Considering the distribution ratio and separation coefficient, when the composite extractant is selected to be composed of tributyl phosphate and n-butanol, and the volume ratio of tributyl phosphate to n-butanol is (6-9): (1-4), the extraction separation effect is the best.

The above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims (4)

1. The application of the composite extractant in recycling waste acid in the waste aluminum chemical polishing solution is characterized by comprising the following steps:

s1, adding a composite extractant and a waste aluminum material chemical polishing solution into an extraction device for fully mixing, and extracting and phase-separating to obtain a load organic phase and raffinate; the volume ratio of the composite extractant to the waste aluminum material chemical polishing solution is (1-4) 1;

S2, adding the loaded organic phase and water in the S1 into an extraction device for fully mixing, and carrying out back extraction to obtain an organic phase and a back extraction liquid; wherein the strip liquor in S2 is a mixed solution of H ₃PO₄ and H ₂SO₄;

the composite extractant consists of tributyl phosphate and n-butyl alcohol, wherein the volume ratio of the tributyl phosphate to the n-butyl alcohol is (6-7): (3-4);

The concentration of H ₃PO₄、H₂SO₄ and Al ³⁺,H₃PO₄ in the waste aluminum material chemical polishing solution is 373.96-378.73 g/L, H ₂SO₄, the concentration of 246.67-268.56 g/L, al ³⁺ and the concentration of 24.54-25.95 g/L.

2. The use of the composite extractant for recycling waste acid in chemical polishing liquid of waste aluminum materials as claimed in claim 1, wherein the volume ratio of the loaded organic phase to water in S2 is (2-7): 1.

3. The use of the composite extractant for recycling waste acid in chemical polishing liquid of waste aluminum materials as claimed in claim 1, wherein the temperature of the extraction in S1 is 10-50 ℃, and the temperature of the back extraction in S2 is 10-50 ℃.

4. The application of the composite extractant in recycling waste aluminum product chemical polishing liquid as claimed in claim 1, wherein the extraction stage number of the extraction in S1 is 1-8; and S2, the extraction stage number of the back extraction is 1-8.