阅读说明：本技术 一种从废电池回收液的萃余液中回收硫酸钠的方法 (Method for recovering sodium sulfate from raffinate of waste battery recovery liquid ) 是由 刘晨明 林晓 石艳春 曹宏斌 于 2019-04-04 设计创作，主要内容包括：本发明属于废水处理技术领域,涉及一种从废电池回收液的萃余液中回收硫酸钠的方法,所述方法包括如下步骤：(1)使用有机溶剂洗脱萃余液；(2)精馏步骤(1)所述洗脱后得到的有机相,得到的有机溶剂回用于步骤(1)所述洗脱；(3)破乳处理步骤(1)所述洗脱后得到的水相,油水分离后所得水相进行深度吸附除油处理；(4)对步骤(3)深度吸附除油处理后得到的水相进行蒸发结晶处理,得到硫酸钠；其中步骤(2)与步骤(3)不分先后顺序。所述方法简单易行,可充分降低蒸发结晶前水相中的油含量与COD,使最终得到的硫酸钠的纯度不低于99.5％,白度不低于90％。(The invention belongs to the technical field of wastewater treatment, and relates to a method for recovering sodium sulfate from raffinate of waste battery recovery liquid, which comprises the following steps: (1) eluting the raffinate with an organic solvent; (2) rectifying the organic phase obtained after elution in the step (1), and reusing the obtained organic solvent in elution in the step (1); (3) demulsifying the water phase obtained after elution in the step (1), and performing deep adsorption oil removal treatment on the water phase obtained after oil-water separation; (4) carrying out evaporative crystallization treatment on the water phase obtained after deep adsorption and oil removal treatment in the step (3) to obtain sodium sulfate; wherein the step (2) and the step (3) are not in sequence. The method is simple and easy to implement, and can fully reduce the oil content and COD in the water phase before evaporation and crystallization, so that the purity of the finally obtained sodium sulfate is not lower than 99.5 percent, and the whiteness is not lower than 90 percent.)

1. A method for recovering sodium sulfate from raffinate of spent battery recycle liquor, comprising the steps of:

(1) eluting the raffinate with an organic solvent;

(2) rectifying the organic phase obtained after elution in the step (1), and reusing the obtained organic solvent in elution in the step (1);

(3) demulsifying the water phase obtained after elution in the step (1), and performing deep adsorption oil removal treatment on the water phase obtained after oil-water separation;

(4) carrying out evaporative crystallization treatment on the water phase obtained after deep adsorption and oil removal treatment in the step (3) to obtain sodium sulfate;

the step (2) and the step (3) are not in sequence.

2. The process according to claim 1, characterized in that the mass fraction of sodium sulfate in the raffinate of step (1) is 10-20%, preferably 12-18%;

preferably, the oil content of the raffinate in the step (1) is 300mg/L, preferably 150 mg/L;

preferably, the COD of the raffinate in the step (1) is 2000-;

preferably, the pH of the raffinate of step (1) is in the range 5 to 6, preferably 5.4 to 5.8.

3. The method according to claim 1 or 2, wherein the organic solvent of step (1) comprises any one or a combination of at least two of cyclohexane, carbon tetrachloride, dichloromethane, chloroform, n-hexane, n-heptane, ethyl acetate, methyl t-butyl ether, n-butanol, or isobutanol.

4. The process according to any one of claims 1 to 3, wherein the organic solvent of step (1) is cyclohexane and/or carbon tetrachloride.

5. The process according to any one of claims 1 to 4, wherein the volume ratio of the organic solvent to the raffinate in step (1) is (0.05-1):1, preferably (0.3-0.6): 1.

6. The method according to any one of claims 1 to 5, wherein the temperature of the elution of step (1) is 20 to 30 ℃, preferably 25 ℃;

preferably, the elution time in step (1) is 10-30min, preferably 15-25 min.

7. The method according to any one of claims 1 to 6, wherein the demulsification treatment in the step (3) is a demulsification treatment using a resin bed layer;

preferably, the resin bed layer is a polystyrene resin bed layer;

preferably, the height-diameter ratio of the resin bed layer is (1-1.5) to 1, preferably (1.2-1.5) to 1;

preferably, the retention time of the aqueous phase obtained after the elution in step (1) in the resin bed is 30-40min, preferably 32-36 min.

8. The method according to any one of claims 1 to 7, wherein the deep adsorption degreasing treatment in the step (3) is a deep adsorption degreasing treatment using an activated carbon bed;

preferably, the height-diameter ratio of the activated carbon bed layer is (1-2):1, preferably (1.6-2): 1.

9. The method according to any one of claims 1 to 8, wherein the water inlet flow rate in the deep adsorption degreasing treatment in the step (3) is 1 to 3BV/h, preferably 1.5 to 2.5 BV/h;

preferably, during the deep adsorption oil removal treatment in the step (3), the water phase obtained after oil-water separation flows in from the bottom of the activated carbon bed layer, and flows out from the top.

10. A method according to any of claims 1-9, characterized in that the method comprises the steps of:

(1) eluting the raffinate by using an organic solvent, wherein the volume ratio of the organic solvent to the raffinate is (0.05-1) to 1, the elution temperature is 20-30 ℃, and the elution time is 10-30 min;

(2) rectifying the organic phase obtained after elution in the step (1), and reusing the obtained organic solvent in elution in the step (1);

(3) performing demulsification treatment on the water phase obtained after elution in the step (1) by using a coalescent resin bed layer with the height-diameter ratio of (1-1.5):1 for 30-40min, performing deep adsorption oil removal treatment on the water phase obtained after oil-water separation in an activated carbon bed layer with the height-diameter ratio of (1-2):1, wherein the water inlet flow is 1-3BV/h, and the water phase obtained after oil-water separation flows in from the bottom and flows out from the top of the activated carbon bed layer;

(4) carrying out evaporative crystallization treatment on the water phase obtained after deep adsorption and oil removal treatment in the step (3) to obtain sodium sulfate, and recovering condensed water generated by evaporative crystallization for later use;

the step (2) and the step (3) are not in sequence.

Technical Field

The invention belongs to the technical field of wastewater treatment, relates to a treatment method of waste battery recovery liquid, and particularly relates to a method for recovering sodium sulfate from raffinate of the waste battery recovery liquid.

Background

The battery waste is a recyclable precious resource, the main valuable elements comprise cobalt, nickel, manganese and lithium, the recovery liquid of the battery waste contains the valuable elements and organic matters brought by a binder and electrolyte in the battery, and a large amount of oil pollutants are introduced when the cobalt, nickel, manganese and lithium in the recovery liquid of the waste battery are extracted and recovered. For example, CN 108002408A discloses a method for preparing nickel sulfate, manganese, lithium, cobalt and cobaltosic oxide from battery waste, in which a large amount of P204 and P507 are introduced during the process of recovering manganese sulfate, cobalt sulfate, nickel sulfate and lithium sulfate, during the extraction process, hydrogen ions on P204 and P507 are exchanged with nickel, cobalt, manganese or lithium, and along with the extraction, the acidity of the solution gradually increases, which is not favorable for further extraction, so that P204 and P507 are usually saponified, but P204 and P507 after saponification can increase the oil content in the recovered solution, which is not favorable for improving the purity and whiteness of sodium sulfate recovered by the subsequent MVR process.

Sodium sulfate, also known as anhydrous sodium sulfate or mirabilite, is one of the inorganic salt industrial products, is in the form of white uniform fine particles or powder, and is mainly used as a filling material for synthetic detergents, a cooking agent in the paper industry or a laxative in the pharmaceutical industry. The main production methods of sodium sulfate include vacuum evaporation, glauberite, conversion or rayon by-product, which are complicated in process, high in cost, difficult in impurity removal, poor in product color and low in recovery rate.

CN 100463855 a discloses a method for producing sodium sulfite and sodium sulfide by using sodium sulfide reduction wastewater, which uses sodium sulfide reduction wastewater as mother liquor to obtain a mixture of sodium sulfite and sodium sulfide, then prepares the mixture into a saturated solution, uses activated carbon to adsorb, decolor, filter-press and remove residues, further performs vacuum evaporation on the removed saturated solution to obtain anhydrous sodium sulfite, and finally obtains sodium sulfide by a concentration or evaporation method.

CN 1069881 a discloses a method for producing sodium sulfide from glauberite, which comprises mixing glauberite powder with coal powder, calcining at high temperature, leaching with sodium sulfate-containing mirabilite water, evaporating and concentrating to obtain sodium sulfide product, but the yield of the method is low.

CN 102887534 a discloses a method for recovering reagent-grade anhydrous sodium sulfate from raffinate obtained by extracting nickel from a nickel sulfate solution, which requires adding hydrogen peroxide for oxidation, and also requires a large amount of activated carbon for adsorption treatment, and does not recover a small amount of nickel ions present in the raffinate.

Therefore, the method for recovering the sodium sulfate from the raffinate of the waste battery recovery liquid is simple, feasible and environment-friendly, and the prepared sodium sulfate has high purity and whiteness, thereby having important significance.

Disclosure of Invention

The invention aims to provide a method for recovering sodium sulfate from raffinate of waste battery recovery liquid, which is simple and easy to operate, can effectively remove organic matters in the raffinate of the waste battery recovery liquid, and finally obtains sodium sulfate with high purity and whiteness, and condensate water generated by evaporative crystallization can be directly used for other processes.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a method for recovering sodium sulfate from raffinate of waste battery recovery liquid, which comprises the following steps:

(1) eluting the raffinate with an organic solvent;

(2) rectifying the organic phase obtained after elution in the step (1), and reusing the obtained organic solvent in elution in the step (1);

(3) demulsifying the water phase obtained after elution in the step (1), and performing deep adsorption oil removal treatment on the water phase obtained after oil-water separation;

(4) carrying out evaporative crystallization treatment on the water phase obtained after deep adsorption and oil removal treatment in the step (3) to obtain sodium sulfate;

the step (2) and the step (3) are not in sequence.

According to the invention, the organic solvent is used for eluting the raffinate, so that COD and oil in the raffinate can be removed primarily, and the organic solvent of the eluted organic phase can be recovered through rectification treatment, so that the use amount of the organic solvent is reduced, and the pollution of the organic solvent to the environment is reduced. The demulsification treatment and the deep adsorption oil removal treatment can further reduce COD and oil in the water phase, so that the finally obtained sodium sulfate has high purity and whiteness.

The rectification method is a conventional method, and a person skilled in the art can select proper rectification parameters according to different organic solvents.

Preferably, the mass fraction of sodium sulfate in the raffinate in step (1) is 10-20%, for example, 10%, 12%, 14%, 16%, 18% or 20%, preferably 12-18%.

Preferably, the oil content of the raffinate in the step (1) is 100-300mg/L, such as 100mg/L, 150mg/L, 200mg/L, 250mg/L or 300mg/L, preferably 150-250 mg/L. The oil in the raffinate of the invention comprises any one of suspension oil, dispersed oil, emulsified oil or dissolved oil or the combination of at least two of the suspension oil, the dispersed oil, the emulsified oil or the dissolved oil.

Preferably, the COD of the raffinate in step (1) is 2000-3000, such as 2000, 2100, 2200, 2300, 2400, 2500, 2600, 2700, 2800, 2900 or 3000, preferably 2400-.

Preferably, the pH of the raffinate in step (1) is 5 to 6, and may be, for example, 5, 5.2, 5.4, 5.6, 5.8 or 6, preferably 5.4 to 5.8.

Preferably, the organic solvent in step (1) comprises any one or a combination of at least two of cyclohexane, carbon tetrachloride, dichloromethane, chloroform, n-hexane, n-heptane, ethyl acetate, methyl tert-butyl ether, n-butanol or isobutanol.

Preferably, the organic solvent in step (1) is cyclohexane and/or carbon tetrachloride.

Preferably, the volume ratio of the organic solvent to the raffinate in step (1) is (0.05-1):1, and may be, for example, 0.05:1, 0.1:1, 0.2:1, 0.3:1, 0.5:1, 0.6:1, 0.8:1 or 1:1, preferably (0.3-0.6): 1.

Preferably, the temperature of the elution in step (1) is 20-30 ℃, for example 20 ℃, 21 ℃, 22 ℃, 23 ℃, 24 ℃, 25 ℃, 26 ℃, 27 ℃, 28 ℃, 29 ℃ or 30 ℃, preferably 25 ℃.

Preferably, the elution time in step (1) is 10-30min, for example 10min, 15min, 20min, 25min or 30min, preferably 15-25 min.

The method uses the organic solvent to elute the raffinate, and the oil content of the water phase after elution is not more than 10mg/L, and the COD is not more than 200.

Preferably, the demulsification treatment in the step (3) is carried out by using a resin bed layer. The oil in the water phase after elution is dispersed small liquid drops, so that oil and water are not easy to separate, the water phase after elution can be layered after being introduced into a resin bed layer, and then oil and water separation is realized, and the resin bed layer is preferably a polystyrene resin bed layer.

Preferably, the height-to-diameter ratio of the resin bed is (1-1.5):1, for example, 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1, preferably (1.2-1.5): 1.

Preferably, the retention time of the aqueous phase obtained after the elution in step (1) in the resin bed is 30-40min, such as 30min, 32min, 34min, 36min, 38min or 40min, preferably 32-36 min.

The oil content in the water phase obtained after the demulsification treatment is not more than 5mg/L, and the COD is not more than 100.

Preferably, the deep adsorption degreasing treatment in the step (3) is a deep adsorption degreasing treatment by using an activated carbon bed layer.

Preferably, the ratio of height to diameter of the activated carbon bed is (1-2):1, for example 1:1, 1.2:1, 1.4:1, 1.6:1, 1.8:1 or 2:1, preferably (1.6-2): 1.

Preferably, the water inlet flow rate in the deep adsorption degreasing treatment in the step (3) is 1-3BV/h, for example, 1BV/h, 1.5BV/h, 2BV/h, 2.5BV/h or 3BV/h, preferably 1.5-2.5 BV/h.

Preferably, during the deep adsorption oil removal treatment in the step (3), the water phase obtained after oil-water separation flows in from the bottom of the activated carbon bed layer, and flows out from the top.

The oil content in the water phase obtained after deep adsorption oil removal treatment is not more than 1mg/L, and the COD is not more than 30.

Preferably, the condensed water generated by the evaporative crystallization in the step (4) is used for leaching the waste battery. The method for evaporative crystallization is a conventional method, a person skilled in the art can select appropriate evaporative crystallization parameters according to process requirements, and the evaporative crystallization in the step (4) of the invention can obtain condensed water and crystallization mother liquor besides a sodium sulfate product, wherein the COD of the condensed water is not more than 20 and can be recycled for later use, and the COD of the crystallization mother liquor is not more than 100 and can be directly discharged.

As a preferred technical scheme of the method, the method comprises the following steps:

(1) eluting the raffinate by using an organic solvent, wherein the volume ratio of the organic solvent to the raffinate is (0.05-1) to 1, the elution temperature is 20-30 ℃, and the elution time is 10-30 min;

(2) rectifying the organic phase obtained after elution in the step (1), and reusing the obtained organic solvent in elution in the step (1);

(3) performing demulsification treatment on the water phase obtained after elution in the step (1) by using a resin bed layer with the height-diameter ratio of (1-1.5):1 for 30-40min, performing deep adsorption oil removal treatment on the water phase obtained after oil-water separation in an activated carbon bed layer with the height-diameter ratio of (1-2):1, wherein the water inlet flow is 1-3BV/h, and the water phase obtained after oil-water separation flows in from the bottom and flows out from the top of the activated carbon bed layer;

(4) carrying out evaporative crystallization treatment on the water phase obtained after deep adsorption and oil removal treatment in the step (3) to obtain sodium sulfate, and recovering condensed water generated by evaporative crystallization for later use;

the step (2) and the step (3) are not in sequence.

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

(1) according to the invention, the oil content and COD in the raffinate are primarily reduced by adding the organic solvent, and the organic solvent obtained by rectification and recovery can be recycled, so that the use amount of the organic solvent is reduced, the cost is reduced, and the environmental pollution caused in the process of recovering sodium sulfate is also reduced;

(2) the method further reduces oil content and COD in the raffinate after elution treatment by using a resin bed layer and an activated carbon bed layer, so that the content of the oil in a water phase before evaporation crystallization is not more than 1mg/L, the COD is not more than 30mg/L, the purity of the finally obtained sodium sulfate is not less than 99.5%, and the whiteness is not less than 90%;

(3) the invention recovers sodium sulfate by an evaporation crystallization method, COD of crystallization mother liquor is not more than 100mg/L and can be directly discharged, and COD in condensed water is not more than 20mg/L and can be directly reused for leaching waste batteries.

Drawings

FIG. 1 is a flow chart of the process for recovering sodium sulfate from the raffinate of the spent battery recycle liquor provided in example 1.

Detailed Description

The technical solution of the present invention is further explained by the following embodiments. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.