Method for carrying out reverse extraction treatment on boron-loaded organic phase by utilizing metallurgical waste brine

Abstract

The invention belongs to the field of hydrometallurgy, and particularly relates to a method for reverse extraction treatment of a boron-loaded organic phase by using metallurgical waste brine, which comprises the following steps: pretreating the metallurgical waste brine by using a porous material in advance to obtain pretreated wastewater, and then carrying out reverse extraction on a low-boron boron-loaded organic phase to obtain a boron-removed reverse organic phase. According to the method, the metallurgical waste brine is innovatively adopted as a stripping agent and is pretreated by adopting a porous material in advance, so that the characteristics of components in the wastewater can be optimized and adjusted, the wastewater is enabled to adapt to the stripping characteristics of a low-boron boron-loaded organic phase, the stripping selectivity of boron in the boron-loaded organic phase and the organic phase is further enhanced, and the stripping efficiency of the boron-loaded organic phase is improved. Therefore, the content of boron in the organic phase is effectively reduced, the solution loss of the organic phase is synchronously reduced, and efficient regeneration of the organic phase is realized. The method not only realizes the utilization of the wastewater, but also obtains a better reverse extraction effect of the boron in the organic phase, and realizes the high-value utilization of the wastewater.

Description

Technical Field

[0001] The present invention relates to the field of hydrometallurgy, and specifically to the field of treatment of boron-loaded organic phases. Background Art

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

[0003] At present, the research focus on the extraction of boric acid is on the extraction stage, and the in-depth research on the stripping stage is not sufficient. Practice has proved that the organic solvent loss in the stripping process is the key to affecting the boric acid extraction cycle. In the existing process, pure water or strong acid and strong base reagents are commonly used as stripping agents, and the stripping rate is low and the cost is high when using chemical reagents. When the boron content in the organic phase is relatively high, boron can be recycled and utilized through crystallization and other means; while when the boron loading in the organic phase is relatively low, the problems of high loss of the extractant in the stripping process, decline in the extraction rate of cyclic extraction, and increase in process cost are closely related. Therefore, how to control the stripping loss has become the key to the research on stripping low-concentration boron.

[0004] Therefore, for boron-loaded organic phases with a relatively high boron content, stripping with pure water, acidic or alkaline stripping agents can effectively enrich the boron in them, with good economic value. However, for boron-loaded organic phases with a relatively low boron content (i.e., the boron content is below 200 ppm), due to the low boron content in them, it is difficult to recover boron by stripping, and the cost is high. From an economic perspective, its industrial application value is limited. Therefore, the key to treating such boron-loaded organic phases with a low boron content lies in how to remove the boron in them at low cost and with high selectivity, while minimizing the loss of the organic phase; however, for such boron-loaded organic phases with a low boron content, there is no targeted low-cost and high-value treatment technology in the existing technology. Summary of the Invention

[0005] Aiming at the problems of low selectivity in the back-extraction separation of boron and the organic phase in the low-boron boron-loaded organic phase, low boron removal efficiency, and large dissolution loss of the organic phase, the first object of the present invention is to provide a method for back-extracting and treating the boron-loaded organic phase using metallurgical waste brine, aiming to remove boron in the low-boron boron-loaded organic phase and reduce the dissolution loss of the organic phase in a way of turning waste to good use.

[0006] For the boron-loaded organic phase with low boron content (referring to the boron content below 200 ppm), the boron content in it is relatively low, making it difficult to recover boron by back-extraction, and the dissolution loss of the organic phase during back-extraction is relatively large, resulting in high treatment costs. Therefore, for such boron-loaded organic phases, how to achieve boron removal at low cost and realize the almost lossless regeneration of the organic phase is the key and difficulty in achieving high-value treatment. In response to this difficulty, the present invention first proposed the idea of using wastewater as a back-extraction agent to back-extract the low-content boron-loaded organic phase in the industry. However, early research and development showed that wastewater has a wide range of sources and complex compositions, and directly using wastewater for back-extraction is difficult to obtain the expected boron removal and almost lossless regeneration effect of the organic phase. In response to the implementation problems faced by the wastewater back-extraction idea, the present invention has provided the following improvement measures through in-depth research:

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

[0008] The present invention innovatively uses metallurgical waste brine as a back-extraction agent and pre-treats it with a porous material in advance, so as to optimize and adjust the composition characteristics of the wastewater to make it adapt to the back-extraction characteristics of the low-boron boron-loaded organic phase, thereby strengthening the back-extraction selectivity of boron and the organic phase in the boron-loaded organic phase, effectively reducing the boron content in the organic phase, synchronously reducing its dissolution loss, and then realizing the efficient regeneration of the organic phase. The present invention not only realizes the utilization of wastewater, but also obtains a better boron removal and regeneration effect, achieving the high-value utilization of wastewater.

[0009] In the present invention, the metallurgical waste brine is a salt-containing wastewater containing at least one of sulfates and hydrochlorides of metal M ions, where the metal M includes at least one of Na, K, Zn, Ni, and Co.

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

[0011] In the present invention, the porous material can be at least one of carbon materials and resins; the carbon material can further be a conventional commercial activated carbon.

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

[0013] In the present invention, in order to obtain good stripping treatment efficiency and effect, the salt condition, concentration and pH of the pretreated wastewater can be reasonably regulated as needed. The salt concentration can be achieved by diluting, concentrating the pretreated wastewater or adding regulating salts.

[0014] In the present invention, the pH of the pretreated wastewater is controlled at 8.00 - 13.50; further, it can be 11 - 13. Research in the present invention shows that stripping the wastewater at the above pH helps to further enhance the effect of boron stripping from the wastewater.

[0015] Preferably, an alkali metal sulfate is used to regulate the concentration of alkali metal ions in the pretreated wastewater to 5 - 25 g / L; further, it can be 5 - 15 g / L. The alkali metal sulfate is at least one of sodium sulfate and potassium sulfate, and preferably potassium sulfate. Research in the present invention shows that innovatively using an alkali metal sulfate, especially potassium sulfate, to regulate the concentration of alkali metal ions in the pretreated wastewater can achieve synergy, further enhance the selectivity of boron removal from the wastewater, improve the boron removal rate, and moreover, effectively reduce the stripping dissolution loss of the organic phase.

[0016] In the present invention, the organic phase in the low - boron boron - loaded organic phase is an alcohol extractant capable of forming a complex with boron.

[0017] In the present invention, the alcohol extractant includes at least one of a unit alcohol extractant and a diol extractant; further, it can be isooctanol. BEPD: EHD:

[0018] TMPD:

[0019] In the present invention, the boron content in the low - boron boron - loaded organic phase is 1 - 200 ppm; further, it can be 20 - 100 ppm.

[0020] In the present invention, the O / A volume ratio in the stripping stage is 1:1 - 32:1; further, it can be 2 - 10:1; still further, it can be 3 - 5:1.

[0021] In the present invention, the stripping method is single - stage stripping, cross - flow stripping or multi - stage counter - current stripping.

[0022] Beneficial effects

[0023] The present invention first proposes an idea of using metallurgical waste brine to strip a low - content boron - loaded organic phase, thereby achieving boron removal and regenerating the organic phase, which is a waste - to - waste approach.

[0024] In order to improve the stripping of boron from metallurgical waste brine and the regeneration effect of the organic phase, the present invention innovatively conducts carbon treatment on the waste brine and jointly controls parameters such as the type and concentration of salts therein, which can help achieve the selective removal of boron, reduce the dissolution loss of the organic phase, and realize the utilization of waste to treat waste.

[0025] The research of the present invention also shows that by controlling the pH of the waste brine at 11-13 and further regulating it with sodium sulfate, potassium sulfate, especially potassium sulfate, the boron stripping effect can be further enhanced. In addition, it helps to inhibit the dissolution loss during the stripping process of the wastewater. Detailed implementation manners

[0026] In the present 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 cases, the waste brine is the stripping solution after the stripping of the nickel-loaded P204 extraction organic phase. Its source and characteristics are as follows: In the nickel sulfate production process, P204 is commonly used for impurity extraction. Among them, the stripping solution after the stripping of the organic phase with hydrochloric acid is often treated as wastewater. The wastewater used in the present invention is the stripping solution of the P204 extraction process in a batch of nickel sulfate production processes. Among them, the component contents of each element are 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 pH = 4.26, COD = 516.00 mg / L, TOC = 326.00 mg / L.

[0027] In the present invention, the metallurgical waste brine can be pre-treated with a porous material, and the porous material can be any commonly known activated carbon in the industry. The steps of its pretreatment are, for example: First, fill the porous material in a columnar container, input the metallurgical waste brine from the inlet, and let it flow through the area filled with the porous material and then flow out from the opposite end (outlet), which is the pre-treated wastewater. As an optional solution, in the present invention, the columnar container is a cylindrical glass tube, with a height of 54 cm and an inner diameter of 3 cm. The loading amount of the porous material can be 120 mL. When necessary, two pretreatment columns filled with the porous material can be connected in series. In the present invention, the flow rate of the wastewater during the pretreatment process can be 0.5 mL / min.

[0028] Example 1

[0029] Use activated carbon to pre-treat the wastewater to obtain pre-treated wastewater, with wastewater TOC = 12.24 mg / L, pH = 4.26.

[0030] Mix the boron-loaded organic phases of the following groups with the wastewater pretreated with activated carbon in a volume ratio of 4:1, set the stripping temperature at 25 °C, the oscillation time at 15 min, let it stand and clarify in an extraction rack for 15 min after the oscillation ends, then separate the phases, and analyze the stripping solution.

[0031] The experimental groups are as follows:

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

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

[0034] C: The boron-loaded organic phase is the complex formed by EHD (Formula 3) and boric acid, and the boron loading is 81.97 ppm.

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

[0036] The results are as follows:

[0037] A: The stripping rate of boric acid is 67.10%, and the TOC of the stripping solution is 362 ppm.

[0038] B: The stripping rate of boric acid is 72.98%, and the TOC of the stripping solution is 468 ppm.

[0039] C: The stripping rate of boric acid is 70.06%, and the TOC of the stripping solution is 452 ppm.

[0040] D: The stripping rate of boric acid is 65.47%, and the TOC of the stripping solution is 470 ppm.

[0041] Comparative Example 1

[0042] Compared with Example 1B, the difference is only that the following pure stripping agents are used to replace the pretreated waste brine for stripping, and other operations and parameters are the same as those in Example 1. The experimental groups and results are as follows:

[0043] The experimental groups are 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 stripping rate of boric acid is 38.94%, and the TOC of the stripping solution is 263.00 ppm.

[0049] B: The stripping rate of boric acid is 78.90%, and the TOC of the stripping solution is 1346.00 ppm.

[0050] C: The stripping rate of boric acid is 51.04%, and the TOC of the stripping solution is 372.00 ppm.

[0051] From Example 1 and Comparative Example 1, it can be seen that by using the waste brine described in the present invention, it can take into account the boron removal effect, and in addition, it can effectively control the dissolution loss of the organic phase.

[0052] Example 2

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

[0054] The experimental groups are as follows:

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

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

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

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

[0059] The results are as follows:

[0060] A: The boron stripping rate is 79.26%, and the TOC of the stripping solution is 666 ppm.

[0061] B: The boron stripping rate is 82.38%, and the TOC of the stripping solution is 724 ppm.

[0062] C: The boron stripping rate is 80.34%, and the TOC of the stripping solution is 770 ppm.

[0063] D: The boron stripping rate is 78.16%, and the TOC of the stripping solution is 774 ppm.

[0064] From Examples 1 and 2, it can be seen that under alkaline conditions, a better boron removal effect can be obtained, but the dissolution loss will also increase to a certain extent.

[0065] Example 3

[0066] Compared with Example 2B, the difference is only that Na2SO4 additive is added to the wastewater for pH regulation to regulate the concentration of Na in the wastewater. The experimental groups are as follows: + respectively:

[0067] A: The concentration of Na in the stripping agent is 4.86 g / L. +

[0068] B: The concentration of Na in the stripping agent is 8.70 g / L. +

[0069] C: The concentration of Na in the stripping agent is 14.2 g / L. +

[0070] Results:

[0071] A: The boron stripping rate is 84.70%, and the TOC of the stripping solution is 396 ppm.

[0072] B: The boron stripping rate is 93.41%, and the TOC of the stripping solution is 243 ppm.

[0073] C: The boron stripping rate is 96.10%, and the TOC of the stripping solution is 229 ppm.

[0074] Compared with Example 2, under alkaline conditions, further using sodium sulfate as a regulator helps with synergy and further strengthens the boron removal effect of the waste brine. Moreover, it can further effectively inhibit the dissolution problem caused by alkaline boron removal.

[0075] Example 4

[0076] Compared with Example 3, the difference is only that the additive is changed to K2SO4, and the concentration of K in the wastewater is controlled. The experimental groups are as follows: + respectively:

[0077] A: The concentration of K in the stripping agent is 4.02 g / L. +

[0078] B: The concentration of K in the stripping agent is 8.43 g / L. +

[0079] C: The concentration of K in the stripping agent is 12.84 g / L. +

[0080] Results:

[0081] A: The boric acid stripping rate is 88.79%, and the TOC of the stripping solution is 312 ppm.

[0082] B: The boric acid stripping rate is 92.46%, and the TOC of the stripping solution is 243 ppm. ​​​​​​

[0083] C: The stripping rate of boric acid is 94.96%, and the TOC of the stripping solution is 205 ppm.

[0084] It can be seen from Examples 3 and 4 that using potassium sulfate as a regulator is helpful to obtain a high boron removal efficiency at a lower ion concentration. In addition, it is also helpful to effectively inhibit the loss of the organic phase during the stripping process of wastewater.

[0085] Example 5

[0086] Compared with Example 3, the pH of the pretreated waste brine was first adjusted to 13.2 with sodium hydroxide, and then sodium sulfate was added to regulate the sodium content to 10 g / L (sodium-adjusted wastewater). Subsequently, the boron-loaded organic phase was mixed with the sodium-adjusted wastewater (stripping agent) at a volume ratio of 5:1. The stripping temperature was set at 25 °C, the oscillation time was 15 min. After the oscillation ended, it was placed in an extraction rack and allowed to stand and clarify for 15 min, and then phase separation was carried out to obtain the regenerated organic phase. The regenerated organic phase after stripping was used as an extractant and mixed with the boron-containing extraction stock solution (boron-containing nickel sulfate solution, where: 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, the oscillation time was 15 min. After the oscillation ended, it was placed in an extraction rack and allowed to stand and clarify for 15 min, and then phase separation was carried out, and 20 single-stage cyclic extractions were carried out.

[0087] The experimental groups were as follows:

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

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

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

[0091] Results:

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

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

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

Claims

1. A method for treating boron-loaded organic phase by back-extraction using metallurgical waste brine, characterized in that, The metallurgical waste brine is pretreated with a porous material to obtain pretreated wastewater, and then the pretreated wastewater is used to back-extract the low-boron boron-loaded organic phase to obtain a boron-depleted regenerated organic phase.

2. The method for back-extracting and treating the boron-loaded organic phase by using metallurgical waste brine according to claim 1, wherein The metallurgical waste brine is a salt-containing wastewater containing at least one of sulfates and hydrochlorides of metal M ions, wherein the metal M includes at least one of Na, K, Zn, Ni, and Co.

3. The method for counter-extracting and treating the boron-loaded organic phase by using metallurgical waste brine according to claim 2, wherein The metallurgical waste brine is process wastewater generated during the production of nickel sulfate.

4. The method for back-extracting and treating the boron-loaded organic phase by using metallurgical waste brine as claimed in claim 2 or 3, characterized in that, The porous material is at least one of carbon materials and resins; The TOC of the pretreated wastewater is below 20 ppm.

5. The method for back-extracting and treating the boron-loaded organic phase by using metallurgical waste brine as claimed in claim 1, wherein, The pH of the pretreated wastewater is controlled at 8.00 - 13.

50.

6. The method for back-extracting and treating the boron-loaded organic phase by using metallurgical waste brine according to claim 1, characterized in that, Alkali metal sulfates are used to regulate the concentration of alkali metal ions in the pretreated wastewater to 5 - 25 g / L.

7. The method for back-extracting and treating boron-loaded organic phase by using metallurgical waste brine as claimed in claim 1, wherein The organic phase in the low-boron boron-loaded organic phase is an alcohol extractant capable of forming a complex with boron; Preferably, the alcohol extractant includes at least one of a unit alcohol extractant and a diol extractant.

8. The method for back-extracting and treating the boron-loaded organic phase by using metallurgical waste brine according to claim 1, characterized in that, The boron content in the low-boron boron-loaded organic phase is 1 - 200 ppm.

9. The method for counter-extracting and treating boron-loaded organic phase by using metallurgical waste brine as claimed in claim 1, wherein The O / A volume ratio in the back-extraction stage is 1:1 - 32:

1.

10. The method for back-extracting and treating boron-loaded organic phase by using metallurgical waste brine as claimed in claim 1, wherein, The back-extraction method is single-stage back-extraction, cross-flow back-extraction, or multi-stage countercurrent back-extraction.