A method for recovering sec-octyl alcohol from tantalum-niobium acid wastewater by extraction-azeotropic distillation

Abstract

The application discloses a method for recovering sec-octyl alcohol from tantalum niobium acid wastewater by extraction and azeotropic distillation, and comprises the following steps: step 1, composite extractant preparation: uniformly mixing dodecane and odorless kerosene according to a certain proportion to obtain a composite extractant; step 2, extraction: adding the composite extractant obtained in step 1 into acid wastewater to carry out extraction, and obtaining raffinate and an organic phase containing sec-octyl alcohol; step 3, azeotropic distillation: adding water or water vapor into the organic phase containing sec-octyl alcohol obtained in step 2 in a distillation device to obtain condensate and the composite extractant; and step 4, phase separation: allowing the condensate obtained in step 3 to stand and separate into phases to obtain sec-octyl alcohol and water. The method realizes short-range purification of sec-octyl alcohol in acid wastewater and recycling of dodecane, solves the problem of strong odor of acid wastewater, realizes resource recycling and high-value utilization of sec-octyl alcohol, and has the characteristics of environmental friendliness, high resource utilization rate and simple and easy-to-implement process.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology and relates to a method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation. Background Technology

[0002] In recent years, with the rapid development of electronics, aerospace, and chemical industries, tantalum, with its excellent electrical conductivity and corrosion resistance, and niobium, with its ability to enhance the strength and toughness of steel, have become irreplaceable rare metals in modern industry and technological development. The main production processes for tantalum and niobium include acid leaching, solvent extraction, and electrolysis, with acid leaching currently being the primary method for recovery. CN201410660973 discloses a method for preparing ultra-high purity tantalum oxide, proposing the use of 2-octanol to extract tantalum. Therefore, the method of using 2-octanol to extract tantalum and niobium to prepare high-purity products is widely used; however, this process generates a large amount of acidic wastewater.

[0003] These acidic wastewaters are characterized by complex composition and high 2-octanol content. The treatment of 2-octanol is crucial for the high-value utilization of acidic wastewater. The main reason is that some 2-octanol dissolves in the acidic wastewater, resulting in a strong odor. Simultaneously, 2-octanol, as an organic solvent, has significant economic value; its multifunctionality and wide range of applications make it an important chemical raw material. In recent years, with the rapid development of electronic information technology, the demand for tantalum and niobium has increased year by year. While wet processing of ores recovers valuable metal elements, the discharge of acidic wastewater has shown a rapid growth trend. Among these, the high economic value of 2-octanol and the strong odor of the acidic wastewater have attracted much attention. Traditional 2-octanol recovery technologies face many challenges, such as complex operation, high cost, and low treatment efficiency. CN201910191881 discloses a method for recovering 2-octanol from lincomycin extraction wastewater, proposing the use of an adsorption medium as an adsorbent to recover 2-octanol from wastewater with a recovery rate of 78%. This method requires multiple liquid mixing operations, which is cumbersome; it requires acidification with an acid concentration of 20-60%, resulting in a large amount of acid being added; and the recovery efficiency is only 78%, which is a low recovery rate.

[0004] Therefore, there is an urgent need for an efficient, economical, and environmentally friendly treatment method to address this challenge. Summary of the Invention

[0005] To address the issues of long process duration and low recovery rate, this invention proposes a method for recovering 2-octanol from tantalum-niobium acidic wastewater via extraction-azeotropic distillation. Using n-dodecane as the extractant, 2-octanol is extracted from the acidic wastewater, and high-purity 2-octanol is obtained through azeotropic distillation. This method achieves short-range purification of 2-octanol from acidic wastewater and recycling of n-dodecane, while also solving the problem of strong odor in acidic wastewater and realizing resource recycling and high-value utilization of 2-octanol. Furthermore, this method is environmentally friendly, has high resource utilization, and is simple and easy to implement.

[0006] To achieve the above objectives, this application adopts the following technical solution: A method for recovering 2-octanol from tantalum-niobium acidic wastewater via extraction-azeotropic distillation, wherein the tantalum-niobium acidic wastewater refers to the acidic wastewater generated during the extraction of tantalum and niobium using 2-octanol, comprising the following steps: Step 1, Preparation of composite extractant: Mix n-dodecane and odorless kerosene in a certain proportion to obtain n-dodecane-odorless kerosene composite extractant; Step 2, Extraction: The composite extractant obtained in Step 1 is added to acidic wastewater for extraction to obtain raffinate and an organic phase containing 2-octanol. The raffinate is then centrally treated. Step 3, azeotropic distillation: The organic phase containing 2-octanol obtained in step 2 is fed into a distillation apparatus, water is added or steam is introduced to obtain condensate and composite extractant; Step 4, phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain 2-octanol and water.

[0007] In the above technical solution, in step 1, the proportion of n-dodecane in the odorless kerosene is 20-60%, wherein the boiling range of the odorless kerosene is 195-300 ℃ and the homogenization time is 5-15 min.

[0008] In the above technical solution, in step 2, the ratio of the composite extractant to the acidic wastewater is 0.5:1 to 2:1.

[0009] In the above technical solution, in step 2, the extraction time is 3-10 min and the phase separation time is 4-10 min.

[0010] In the above technical solution, in step 3, the distillation temperature is 80-220 ℃ and the time is 30-100 min.

[0011] In the above technical solution, the composite extractant obtained in step 3 is recycled back to step 2.

[0012] In the above technical solution, the water obtained in step 4 is returned to step 3 for recycling.

[0013] The beneficial effects of this invention are as follows: Compared with the prior art, this invention uses n-dodecane to recover 2-octanol from acidic wastewater, employing n-dodecane as an extractant for one-step extraction of 2-octanol. High-purity 2-octanol is obtained through azeotropic distillation, while the diluted n-dodecane is recycled. This method does not require the addition of other reagents during implementation, achieving short-path purification of 2-octanol and solving the problem of strong odor in acidic wastewater. It features simple and easy-to-implement process, high resource utilization, and environmental friendliness. Attached Figure Description

[0014] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the accompanying drawings are merely schematic illustrations, used to help illustrate the technical solutions and preferred embodiments of the present invention, and do not constitute a limitation on the scope of protection of the technical solutions of the present invention. Within the scope defined by the claims of the present invention, any equivalent transformations or modifications based on the principles of the present invention should be considered to fall within the protection scope of the present invention.

[0015] Figure 1 This is a flowchart of the method for extracting and recovering 2-octanol from acidic tantalum-niobium wastewater according to the present invention. Detailed Implementation

[0016] To better illustrate the objectives, technical solutions, and advantages of this invention, the invention will be further described below in conjunction with specific embodiments. This invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the inventive concept to those skilled in the art. This invention will be defined only by the claims.

[0017] This invention relates to the treatment of acidic wastewater generated during tantalum and niobium production and the purification and recovery technology of 2-octanol, particularly a novel method for extracting 2-octanol from acidic wastewater using n-dodecane organic phase, thereby providing a method for extracting and recovering 2-octanol from tantalum and niobium acidic wastewater.

[0018] Example 1

[0019] A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 40% of odorless kerosene, the boiling point of odorless kerosene is 220 ℃, and the homogenization time is 7 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 2, the extraction time is 7 min, and the phase separation time is 8 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 150 °C and the time is 80 min.

[0020] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0021] The extraction rate of 2-octanol was 99.56%, and the purity of the obtained 2-octanol was 99.12%, which meets the test requirements of the national standard GB / T 9722-2023 General Rules for Gas Chromatography.

[0022] Example 2

[0023] A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 30% of odorless kerosene, the boiling point of odorless kerosene is 250 ℃, and the homogenization time is 10 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 1, the extraction time is 10 min, and the phase separation time is 5 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 160 °C and the time is 90 min.

[0024] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0025] The extraction rate of 2-octanol was 98.97%, and the purity of the obtained 2-octanol was 98.99%, which meets the test requirements of the national standard GB / T 9722-2023 General Rules for Gas Chromatography.

[0026] Example 3

[0027] A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 50% of odorless kerosene, the boiling point of odorless kerosene is 230 ℃, and the homogenization time is 12 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 0.5, the extraction time is 5 min, and the phase separation time is 9 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 170 °C and the time is 100 min.

[0028] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0029] The extraction rate of 2-octanol was 99.43%, and the purity of the obtained 2-octanol was 99.28%, which meets the test requirements of the national standard GB / T 9722-2023 General Rules for Gas Chromatography.

[0030] Example 4

[0031] A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 55% of odorless kerosene, the boiling point of odorless kerosene is 270 ℃, and the homogenization time is 11 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 2, the extraction time is 6 min, and the phase separation time is 8 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 200 °C and the time is 70 min.

[0032] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0033] The extraction rate of 2-octanol was 99.56%, and the purity of the obtained 2-octanol was 99.12%, which meets the test requirements of the national standard GB / T 9722-2023 General Rules for Gas Chromatography.

[0034] Example 5

[0035] A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 50% of odorless kerosene, the boiling point of odorless kerosene is 245 ℃, and the homogenization time is 13 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 2, the extraction time is 10 min, and the phase separation time is 8 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 180 °C and the time is 70 min.

[0036] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0037] The extraction rate of 2-octanol was 99.09%, and the purity of the obtained 2-octanol was 99.37%, which meets the test requirements of the national standard GB / T 9722-2023 General Rules for Gas Chromatography.

[0038] Comparative Example 1 A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 40% of odorless kerosene, the boiling point of odorless kerosene is 180 ℃, and the homogenization time is 10 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 2, the extraction time is 10 min, and the phase separation time is 8 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 180 °C and the time is 70 min.

[0039] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0040] The extraction rate of 2-octanol was 99.46%, and the purity of the obtained 2-octanol was 47.21%, which meets the test requirements of the general rules of gas chromatography in the national standard GB / T 9722-2023. The low purity is due to the kerosene used (boiling point 180 ℃, 2-octanol boiling point 196 ℃), and the azeotropic distillation temperature of 220 ℃, which caused some odorless kerosene to evaporate, resulting in low 2-octanol purity.

[0041] Comparative Example 2 A method for recovering 2-octanol from tantalum-niobium acidic wastewater by extraction-azeotropic distillation includes the following steps: (1) Preparation of composite extractant: Mix odorless kerosene and n-dodecane evenly to obtain composite extractant, wherein n-dodecane accounts for 40% of odorless kerosene, the boiling point of odorless kerosene is 240 ℃, and the homogenization time is 15 min; (2) Extraction: The composite extractant obtained in step (1) is added to the tantalum-niobium acidic wastewater to extract 2-octanol, and the raffinate and the organic phase containing 2-octanol are obtained. The raffinate is centrally treated. The ratio of the composite extractant to the tantalum-niobium acidic wastewater is 2, the extraction time is 8 min, and the phase separation time is 9 min. (3) Azeotropic distillation: The organic phase containing octanol obtained in step (2) is azeotropically distilled to obtain condensate and composite extractant. The composite extractant is recycled back to step (2). The azeotropic distillation temperature is 210 °C and the time is 80 min.

[0042] (4) Phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain octanol and water (return to step 3 for recycling).

[0043] The extraction rate of 2-octanol was 42.31%, and the purity of the obtained 2-octanol was 98.91%, which meets the test requirements of the national standard GB / T 9722-2023 General Rules for Gas Chromatography. The main reason for the low extraction rate is that n-dodecane accounts for only 5% of the odorless kerosene, and the n-dodecane is diluted by the odorless kerosene, resulting in low extraction capacity.

[0044] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for recovering 2-octanol from tantalum-niobium acidic wastewater via extraction-azeotropic distillation, wherein the tantalum-niobium acidic wastewater refers to the acidic wastewater generated during the extraction of tantalum and niobium using 2-octanol, characterized in that: Includes the following steps: Step 1, Preparation of composite extractant: Mix n-dodecane and odorless kerosene in a certain proportion to obtain n-dodecane-odorless kerosene composite extractant; Step 2, Extraction: The composite extractant obtained in Step 1 is added to acidic wastewater for extraction to obtain raffinate and an organic phase containing 2-octanol. The raffinate is then centrally treated. Step 3, azeotropic distillation: The organic phase containing 2-octanol obtained in step 2 is fed into a distillation apparatus, water is added or steam is introduced to obtain condensate and composite extractant; Step 4, phase separation: The condensate obtained in step 3 is allowed to stand and separate to obtain 2-octanol and water.

2. The method according to claim 1, characterized in that: In step 1, the proportion of n-dodecane in the odorless kerosene is 20-60%, wherein the boiling range of the odorless kerosene is 195-300 ℃ and the homogenization time is 5-15 min.

3. The method according to claim 1, characterized in that: In step 2, the ratio of the composite extractant to the acidic wastewater is 0.5:1 to 2:

1.

4. The method according to claim 1, characterized in that: In step 2, the extraction time is 3-10 min and the phase separation time is 4-10 min.

5. The method according to claim 1, characterized in that: In step 3, the distillation temperature is 80-220 ℃ and the time is 30-100 min.

6. The method according to claim 1, characterized in that: The composite extractant obtained in step 3 is recycled back to step 2.

7. The method according to claim 1, characterized in that: The water obtained in step 4 is returned to step 3 for recycling.

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