Process for the treatment of boron-loaded organic phases with metallurgical waste brine back extraction

Abstract

The present application belongs to the field of hydrometallurgy, and particularly relates to a method for treating boron-loaded organic phase by using metallurgical waste brine back extraction, wherein the metallurgical waste brine is pretreated by using a porous material to obtain pretreated waste water, and then the low-boron boron-loaded organic phase is back extracted to obtain a deboronized back-extracted organic phase. The present application innovatively uses metallurgical waste brine as a back extraction agent, and pretreats the same by using a porous material, so that the composition characteristics of the waste water can be optimized and adjusted to adapt to the back extraction characteristics of the low-boron boron-loaded organic phase, thereby enhancing the back extraction selectivity of boron in the boron-loaded organic phase and the organic phase, so as to effectively reduce the boron content in the organic phase and simultaneously reduce the solution loss, and thus realize efficient regeneration of the organic phase. The present application not only realizes the utilization of waste water, but also obtains a more optimal back extraction effect of boron in the organic phase, and realizes high-value utilization of waste water.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgy, and more specifically to the field of boron-supported organic phase treatment. Background Technology

[0002] With the rapid development of the new energy industry, the demand for new energy vehicle batteries is constantly increasing, and the demand for nickel sulfate, one of the important raw materials for ternary cathode materials in batteries, is also showing a significant growth trend. The quality of nickel sulfate directly affects the performance of the battery. Most impurity elements (iron, copper, zinc, etc.) in crude nickel sulfate solutions can be efficiently removed by metallurgical separation methods, but research on the deep removal of trace amounts of boron is not comprehensive. Commonly used boron removal processes include precipitation, adsorption, solvent extraction, and ion exchange. Among them, solvent extraction is considered a technology with great industrial potential due to its simple operation and good separation effect. Commonly used boron extractants include monohydric alcohols and dihydric alcohols. Dihydric alcohols (such as 1,3-dialisic alcohols) are widely used in boron extraction from salt lake brine due to their excellent complexing ability.

[0003] Current research on boric acid extraction focuses on the extraction stage, while in-depth research on the back-extraction stage is insufficient. Practice has shown that organic solvent loss during back-extraction is a key factor affecting the boric acid extraction cycle. Existing processes commonly use pure water or strong acid / base reagents as back-extraction agents, resulting in low back-extraction rates and high costs when using chemical reagents. When the boron content in the organic phase is high, boron can be recovered and utilized through crystallization and other methods; however, when the boron loading in the organic phase is low, the high solvent loss during back-extraction is closely related to decreased extraction rates and increased process costs. Therefore, controlling solvent loss during back-extraction has become a crucial aspect of research on back-extraction of low-concentration boron.

[0004] Therefore, for boron-loaded organic phases with high boron content, back-extraction using pure water, acidic or alkaline stripping agents can effectively enrich the boron, which has good economic value. However, for boron-loaded organic phases with low boron content (i.e., boron content below 200 ppm), due to the low boron content, back-extraction to recover boron is difficult and costly, limiting its industrial application value from an economic perspective. Therefore, the key to treating this type of low-boron-content boron-loaded organic phase lies in how to remove boron in a low-cost and highly selective manner while minimizing the loss of the organic phase; however, existing technologies do not yet offer targeted, low-cost, high-value treatment technologies for this type of low-boron-content boron-loaded organic phase. Summary of the Invention

[0005] To address the problems of low selectivity, low boron removal efficiency, and significant organic phase dissolution in the back-extraction separation of boron and organic phases in low-boron boron-loaded organic phases, the primary objective of this invention is to provide a method for back-extraction treatment of boron-loaded organic phases using metallurgical waste brine. This method aims to remove boron from low-boron boron-loaded organic phases and reduce organic phase dissolution through a waste-to-waste process.

[0006] For boron-loaded organic phases with low boron content (below 200 ppm), the low boron concentration makes boron recovery through back-extraction difficult, and the back-extraction process results in significant organic phase loss and high processing costs. Therefore, achieving low-cost boron removal and near-non-destructive regeneration of the organic phase is crucial for high-value treatment of this type of boron-loaded organic phase. To address this challenge, this invention is the first in the industry to propose using wastewater as a back-extraction agent for low-boron-content organic phases. However, early research revealed that wastewater sources are diverse and complex, making it difficult to achieve the desired boron removal and near-non-destructive organic phase regeneration through direct wastewater back-extraction. To address the implementation difficulties of the wastewater back-extraction approach, this invention, after in-depth research, provides the following improvements:

[0007] A method for back-extracting boron-loaded organic phases using metallurgical waste brine involves pre-treating the metallurgical waste brine with a porous material to obtain pre-treated wastewater, and then using the pre-treated wastewater to back-extract a low-boron boron-loaded organic phase to obtain a deboronized regenerated organic phase.

[0008] This invention innovatively uses metallurgical wastewater as a back-extraction agent and pre-treats it with porous materials. This optimizes the composition of the wastewater to suit the back-extraction characteristics of low-boron boron-loaded organic phases, thereby enhancing the back-extraction selectivity of boron in the boron-loaded organic phase and effectively reducing the boron content in the organic phase while simultaneously reducing its dissolution loss, thus achieving efficient regeneration of the organic phase. This invention not only realizes the utilization of wastewater but also achieves superior boron removal and regeneration effects, realizing the high-value utilization of wastewater.

[0009] In this invention, the metallurgical wastewater is a saline wastewater containing at least one of sulfates and hydrochlorides containing metal M ions, wherein the metal M includes at least one of Na, K, Zn, Ni, and Co.

[0010] In this invention, the metallurgical wastewater is process wastewater generated during the production of nickel sulfate.

[0011] In this invention, the porous material can be at least one of carbon material and resin; the carbon material can further be conventional commercial activated carbon.

[0012] Preferably, the TOC of the pretreated wastewater is below 20 ppm, for example, it can be 5 to 20 ppm.

[0013] In this invention, to obtain good back-extraction efficiency and effect, the salt content, concentration, and pH of the pretreated wastewater can be reasonably controlled as needed. The salt concentration can be achieved by diluting, concentrating, or adding adjusting salts to the pretreated wastewater.

[0014] In this invention, the pH of the pretreated wastewater is controlled between 8.00 and 13.50; more specifically, it can be between 11 and 13. Research in this invention indicates that back-extracting the wastewater at the specified pH helps to further enhance the boron removal effect of the wastewater back-extraction.

[0015] Preferably, alkali metal sulfates are used to control the concentration of alkali metal ions in the pretreated wastewater to 5–25 g / L; more preferably, it can be 5–15 g / L. The alkali metal sulfate is at least one of sodium sulfate and potassium sulfate, preferably potassium sulfate. This invention demonstrates that the innovative use of alkali metal sulfates, particularly potassium sulfate, to control the concentration of alkali metal ions in the pretreated wastewater achieves a synergistic effect, further enhancing the selectivity of wastewater for boron removal, improving the boron removal rate, and effectively reducing the back-extraction loss of the organic phase.

[0016] In this invention, the organic phase in the low-boron boron-loaded organic phase is an alcohol extractant that can form a complex with boron.

[0017] In this invention, the alcohol extractant includes at least one of monohydric alcohol extractants and dihydric alcohol extractants; further, it can be isooctanol. BEPD: EHD:

[0018] TMPD:

[0019] In this invention, the boron content in the low-boron boron-supported organic phase is 1–200 ppm; more specifically, it can be 20–100 ppm.

[0020] In this invention, the O / A volume ratio in the back-extraction stage is 1:1 to 32:1; further, it can be 2 to 10:1; and even further, it can be 3 to 5:1.

[0021] In this invention, the back-extraction method is single-stage back-extraction, cross-flow back-extraction, or multi-stage countercurrent back-extraction.

[0022] Beneficial effects

[0023] This invention is the first to propose a waste-to-waste approach that uses metallurgical waste brine to back-extract low-boron-content organic phases, thereby achieving boron removal and regeneration of the organic phases.

[0024] To improve the back-extraction boron removal and organic phase regeneration effects of metallurgical waste brine, this invention innovatively incorporates carbon treatment of the waste brine, along with combined control of parameters such as salt type and concentration. This approach helps achieve selective boron removal and reduces organic phase loss, enabling waste-to-waste treatment.

[0025] The present invention also shows that controlling the pH of waste brine at 11-13 and further adjusting it with sodium sulfate, potassium sulfate, and especially potassium sulfate can further enhance the boron removal effect. In addition, it also helps to suppress the dissolution loss during the wastewater back-extraction process. Detailed Implementation

[0026] In this invention, the metallurgical waste brine can be any waste process water containing metal salts in the metallurgical field. For example, as an optional solution, in the following case, the waste brine is the back-extraction liquid after the organic phase of nickel-loaded P204 extraction is back-extracted. Its source and characteristics are as follows: P204 extraction is commonly used to remove impurities in the nickel sulfate production process, and the back-extraction liquid after the organic phase is back-extracted with hydrochloric acid is often treated as wastewater. The wastewater used in this invention is the back-extraction liquid from the P204 extraction process in a certain batch of nickel sulfate production, wherein the elemental composition is as follows: Ni: 18.85 mg / L, As: 0.59 mg / L, Ca: 17.15 mg / L, Cd: 0.32 mg / L, Cu: 8.07 mg / L, Fe: 377.40 mg / L, Zn: 873.00 mg / L, Na: 105.60 mg / L. The wastewater has a pH of 4.26, a COD of 516.00 mg / L, and a TOC of 326.00 mg / L.

[0027] In this invention, metallurgical wastewater can be pretreated with a porous material, which can be any known activated carbon in the industry. The pretreatment steps include, for example, filling a cylindrical container with the porous material, inputting the metallurgical wastewater through the inlet, allowing it to flow through the porous material-filled area, and then exiting from the opposite end (outlet), thus obtaining the pretreated wastewater. Optionally, the cylindrical container is a cylindrical glass tube with a height of 54 cm and an inner diameter of 3 cm, and the porous material filling volume can be 120 mL. If necessary, two pretreatment columns filled with porous material can be connected in series. In this invention, the flow rate of the wastewater during the pretreatment process can be 0.5 mL / min.

[0028] Example 1

[0029] Activated carbon was used to pretreat the wastewater, resulting in pretreated wastewater with a TOC of 12.24 mg / L and a pH of 4.26.

[0030] The boron-loaded organic phases of the following groups were mixed with the wastewater after activated carbon pretreatment at a volume ratio of 4:1. The back-extraction temperature was set at 25℃ and the shaking time was 15 min. After shaking, the mixture was placed in an extraction rack and allowed to stand for clarification for 15 min before phase separation. The back-extraction liquid was then taken for analysis.

[0031] The experimental groups were as follows:

[0032] A: The boron-loaded organic phase is a complex formed by isooctanol (Formula 1) and boric acid, with a boron loading of 48.61 ppm.

[0033] B: The boron-loaded organic phase is a complex formed by BEPD (Formula 2) and boric acid, with a boron loading of 77.46 ppm.

[0034] C: The boron-loaded organic phase is a complex formed by EHD (Formula 3) and boric acid, with a boron loading of 81.97 pp m.

[0035] D: The boron-loaded organic phase is a complex formed by TMPD (Formula 4) and boric acid, with a boron loading of 64.28 ppm.

[0036] The results are as follows:

[0037] A: The boric acid back-extraction rate was 67.10%, and the TOC of the back-extraction solution was 362 ppm.

[0038] B: The boric acid back-extraction rate was 72.98%, and the TOC of the back-extraction solution was 468 ppm.

[0039] C: Boric acid back-extraction rate was 70.06%, and the TOC of the back-extraction solution was 452 ppm.

[0040] D: The boric acid back-extraction rate was 65.47%, and the TOC of the back-extraction solution was 470 ppm.

[0041] Comparative Example 1

[0042] Compared with Example 1B, the only difference is that the pretreated waste brine is replaced with the following pure back-extractant for back-extraction. All other operations and parameters are the same as in Example 1. The experimental groups and results are as follows:

[0043] The experimental groups were as follows:

[0044] A: The stripping agent is pure water.

[0045] B: The stripping agent is 0.1M NaOH.

[0046] C: The stripping agent is 0.1M HCl.

[0047] The results are as follows:

[0048] A: The boric acid back-extraction rate is 38.94%, and the TOC of the back-extraction solution is 263.00 ppm.

[0049] B: The boric acid back-extraction rate was 78.90%, and the TOC of the back-extraction solution was 1346.00 ppm.

[0050] C: The boric acid back-extraction rate was 51.04%, and the TOC of the back-extraction solution was 372.00 ppm.

[0051] As can be seen from Example 1 and Comparative Example 1, the waste brine described in this invention can achieve both boron removal and effective control of organic phase loss.

[0052] Example 2

[0053] Compared to Example 1, the only difference is that powdered sodium hydroxide was added to adjust the pH of the wastewater after activated carbon pretreatment to 12.26, and the sodium content in the wastewater was 0.51 g / L. The boron-loaded organic phase was mixed with the pH-adjusted wastewater at a volume ratio of 4:1. The back-extraction temperature was set to 25°C, and the shaking time was 15 min. After shaking, the mixture was placed in an extraction rack and allowed to stand for clarification for 15 min before phase separation. The back-extraction liquid was then taken for analysis.

[0054] The experimental groups were as follows:

[0055] A: A complex formed by isooctyl alcohol (Formula 1) and boric acid, with a loading of 48.61 ppm.

[0056] B: A complex formed by BEPD (Formula 2) and boric acid, with a loading of 77.46 ppm.

[0057] C: A complex formed by EHD (Formula 3) and boric acid, with a loading of 81.97 ppm.

[0058] D: A complex formed by TMPD (Formula 4) and boric acid, with a loading of 64.28 ppm.

[0059] The results are as follows:

[0060] A: The boron back-extraction rate was 79.26%, and the TOC of the back-extraction solution was 666 ppm.

[0061] B: Boron back-extraction rate was 82.38%, and the TOC of the back-extraction solution was 724 ppm.

[0062] C: Boron back-extraction rate was 80.34%, and the TOC of the back-extraction solution was 770 ppm.

[0063] D: Boron back-extraction rate was 78.16%, and the TOC of the back-extraction solution was 774 ppm.

[0064] As can be seen from Examples 1 and 2, better deboronization can be achieved under alkaline conditions, but this will also increase the dissolution loss to some extent.

[0065] Example 3

[0066] Compared to Example 2B, the only difference is that Na2SO4 additive is added to the wastewater to adjust the pH, thereby adjusting the Na content in the wastewater. + The concentrations in the experimental groups were as follows:

[0067] A: Na in the stripping agent + Concentration 4.86 g / L.

[0068] B: Na in the stripping agent + Concentration 8.70 g / L.

[0069] C: Na in the stripping agent + Concentration 14.2 g / L.

[0070] result:

[0071] A: The boron back-extraction rate was 84.70%, and the TOC of the back-extraction solution was 396 ppm.

[0072] B: Boron back-extraction rate was 93.41%, and the TOC of the back-extraction solution was 243 ppm.

[0073] C: The boron back-extraction rate was 96.10%, and the TOC of the back-extraction solution was 229 ppm.

[0074] Compared with Example 2, the use of sodium sulfate as a regulator under alkaline conditions helps to synergistically enhance the boron removal effect of waste brine. Moreover, it can further effectively suppress the dissolution loss caused by alkaline boron removal.

[0075] Example 4

[0076] Compared to Example 3, the only difference is that the additive is changed to K2SO4, and the K in the wastewater is controlled. + Concentration, experimental groups were as follows:

[0077] A: K in the stripping agent + Concentration 4.02 g / L.

[0078] B: K in the stripping agent + Concentration 8.43 g / L.

[0079] C: K in the stripping agent + Concentration 12.84 g / L.

[0080] result:

[0081] A: The boric acid back-extraction rate was 88.79%, and the TOC of the back-extraction solution was 312 ppm.

[0082] B: The boric acid back-extraction rate was 92.46%, and the TOC of the back-extraction solution was 243 ppm.

[0083] C: The boric acid back-extraction rate was 94.96%, and the TOC of the back-extraction solution was 205 ppm.

[0084] As can be seen from Examples 3 and 4, using potassium sulfate as a regulator helps to achieve high boron removal efficiency at lower ion concentrations. In addition, it also helps to effectively suppress the organic phase loss during wastewater back-extraction.

[0085] Example 5

[0086] Compared to Example 3, the pretreated wastewater was first adjusted to pH 13.2 with sodium hydroxide, and then sodium sulfate was added to adjust the sodium content to 10 g / L (sodium-adjusting wastewater). The boron-loaded organic phase was then mixed with the sodium-adjusting wastewater (extraction agent) at a volume ratio of 5:1. The extraction temperature was set at 25°C, and the shaking time was 15 min. After shaking, the mixture was placed in an extraction rack and allowed to stand for clarification for 15 min before phase separation to obtain a regenerated organic phase. This regenerated organic phase was used as the extraction agent and mixed with the boron-containing extraction stock solution (boron-containing nickel sulfate solution, wherein: Ni: 82.0 g / L, Fe: 8.72 g / L, Cu: 13.6 g / L, Zn: 6.86 g / L, B: 50.2 ppm) at a volume ratio of 1:1. The single-stage extraction temperature was set at 25°C, and the shaking time was 15 min. After shaking, the mixture was placed in an extraction rack and allowed to stand for clarification for 15 min before phase separation. This process was repeated 20 times for single-stage cyclic extraction.

[0087] The experimental groups were as follows:

[0088] A: BEPD (Formula 2) as the extractant

[0089] B: EHD (Formula 3) as extractant

[0090] C: TMPD (Formula 4) is used as the extractant.

[0091] result:

[0092] A: The initial single-stage extraction rate was 78.39%, and after 20 cycles, the single-stage extraction rate was 74.16%.

[0093] B: The initial single-stage extraction rate was 81.90%, and after 20 cycles, the single-stage extraction rate was 80.23%.

[0094] C: The initial single-stage extraction rate was 68.85%, and after 20 cycles, the single-stage extraction rate was 63.82%.

Claims

1. A method for back-extracting boron-loaded organic phases using metallurgical waste brine, characterized in that, Metallurgical wastewater was pretreated with porous materials to obtain pretreated wastewater. The pH of the pretreated wastewater was controlled at 8.00~13.

50. Subsequently, the pretreated wastewater was used to back-extract the low boron-loaded organic phase to obtain the deboronized regenerated organic phase. The metallurgical wastewater is a saline wastewater containing at least one of sulfates and hydrochlorides containing metal M ions, wherein the metal M includes at least one of Na, K, Zn, Ni, and Co. The organic phase in the low-boron boron-loaded organic phase is an alcohol extractant that can form a complex with boron; the alcohol extractant includes at least one of monohydric alcohol extractants and dihydric alcohol extractants. The boron content in the low-boron boron-supported organic phase is 1~200 ppm; The TOC of the pretreated wastewater is below 20 ppm.

2. The method for back-extracting boron-supported organic phases using metallurgical waste brine as described in claim 1, characterized in that, The metallurgical wastewater is process wastewater generated during the production of nickel sulfate.

3. The method for back-extracting boron-supported organic phases using metallurgical waste brine as described in claim 2, characterized in that, The porous material is at least one of carbon material and resin.

4. The method for back-extracting boron-supported organic phases using metallurgical waste brine as described in claim 1, characterized in that, Alkali metal sulfates were used to control the concentration of alkali metal ions in the pretreated wastewater to 5-25 g / L.

5. The method for back-extracting boron-supported organic phases using metallurgical waste brine as described in claim 1, characterized in that, The alcohol extractant is isooctanol, BEPD, EHD, or TMPD; Wherein, BEPD is ; EHD is ; TMPD is .

6. The method for back-extracting boron-supported organic phases using metallurgical waste brine as described in claim 1, characterized in that, The O / A volume ratio during the back-extraction stage is 1:1 to 32:

1.

7. The method for back-extracting boron-supported organic phases using metallurgical waste brine as described in claim 1, characterized in that, The back-extraction methods include single-stage back-extraction, cross-flow back-extraction, or multi-stage counter-flow back-extraction.

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