阅读说明：本技术 光刻胶剥离液废液中回收nmf和mdg的方法和装置 (Method and device for recovering NMF and MDG from waste photoresist stripping solution ) 是由 赵瑞红 宋可欣 刘玉敏 李昆杰 谢楠 李凯 于 2021-02-24 设计创作，主要内容包括：本发明涉及一种光刻胶剥离液废液中回收NMF和MDG的方法,其包括如下步骤：(1)光刻胶剥离液废液经过滤后进行脱水处理；(2)对脱水后的光刻胶剥离液废液进行减压精馏,得到NMF和MDG的混合物以及高沸物；(3)对NMF和MDG的混合物进行电解,得到NMF和MDG的回收液；(4)对高沸物进行焚烧处理。本发明还涉用于上述方法的装置。本发明的流程简单、成本低、适于大规模推广。(The invention relates to a method for recovering NMF and MDG from a photoresist stripping solution waste liquid, which comprises the following steps: (1) filtering the waste photoresist stripping solution and then dehydrating; (2) performing reduced pressure rectification on the dehydrated photoresist stripping liquid waste liquid to obtain a mixture of NMF and MDG and a high-boiling-point substance; (3) electrolyzing the mixture of NMF and MDG to obtain a recovery solution of NMF and MDG; (4) and (4) carrying out incineration treatment on the high-boiling-point substances. The invention also relates to a device for the method. The method has the advantages of simple process, low cost and suitability for large-scale popularization.)

1. A method for recovering NMF and MDG from a waste photoresist stripping solution is characterized by comprising the following steps:

(1) filtering the waste photoresist stripping solution and then dehydrating;

(2) performing reduced pressure rectification on the dehydrated photoresist stripping liquid waste liquid to obtain a mixture of NMF and MDG and a high-boiling-point substance;

(3) electrolyzing the mixture of NMF and MDG to obtain a recovery solution of NMF and MDG;

(4) and (4) carrying out incineration treatment on the high-boiling-point substances.

2. The method for recovering NMF and MDG from the waste photoresist stripper solution of claim 1, wherein in the step (1), the filtered waste photoresist stripper solution is dehydrated by a dehydration tower, wherein the pressure at the top of the dehydration tower is 10-12kPa, the temperature at the top of the dehydration tower is 50-75 ℃, and the temperature at the bottom of the dehydration tower is 70-100 ℃.

3. The method for recovering NMF and MDG from the waste photoresist stripper solution of claim 2, wherein the pressure at the top of the dehydration tower is 10kPa, the temperature at the top of the dehydration tower is 71 ℃, and the temperature at the bottom of the dehydration tower is 93 ℃.

4. The method for recovering NMF and MDG from the waste photoresist stripper according to claim 1, wherein in the step (2), the distillation under reduced pressure is performed by using a refining tower; the refining tower is a sieve plate tower, the pressure at the top of the tower is set to be 10-12kPa, the temperature at the top of the tower is 90-120 ℃, and the temperature at the bottom of the tower is 130-160 ℃.

5. The method of claim 4, wherein the top pressure of the refining column is 10kPa, the top temperature is 118 ℃ and the bottom temperature is 156 ℃.

6. The method for recovering NMF and MDG from the waste photoresist stripper according to claim 1, wherein in the step (3), an electrolytic cell is used for electrolysis; the temperature of the electrolytic cell is 30-45 ℃, the distance between polar plates is 9-13mm, and the current density is 8-13mA/cm²Electrolyzing for 20-30min under the condition of (1).

7. The method for recovering NMF and MDG from the waste liquid of photoresist stripper according to claim 6, wherein the temperature of the electrolytic cell is 35 ℃, the distance between the plates is 9mm, and the current density is 8mA/cm²Electrolysis was carried out for 20min under the conditions of (1).

8. An apparatus used in the method for recovering NMF and MDG from the waste photoresist stripper solution of any one of claims 1 to 7, comprising a waste solution tank (1), wherein the waste solution tank (1) is connected to a dehydrating tower (3) through a first connecting pipe (2), a pure water tank (4) is connected to the top of the dehydrating tower (3), a refining tower (6) is connected to the bottom of the dehydrating tower (3) through a second connecting pipe (5), an electrolytic tank (8) is connected to the top of the refining tower (6) through a third connecting pipe (7), a high boiling substance storage tank (9) is connected to the bottom of the refining tower (6), and the electrolytic tank (8) is connected to a recovery tank (11) through a fourth connecting pipe (10).

9. The device according to claim 8, characterized in that centrifugal pumps (12) are arranged on the first connecting duct (2), the second connecting duct (5), the third connecting duct (7) and the fourth connecting duct (10).

Technical Field

The invention relates to treatment of a photoresist stripping solution waste liquid generated in a TFT-LCD production process, in particular to a method for recovering NMF and MDG from the photoresist stripping solution waste liquid.

Background

In recent years, the domestic electronic manufacturing industry has been rapidly developed, and the amount of used electronic chemicals such as stripping liquid has been greatly increased. In the production process of electronic components such as liquid crystal display panels and semiconductor integrated circuits, it is necessary to remove the resist as a mask with a stripping liquid several times. The stripping solution used in industry is usually composed of organic amine and polar organic solvent, and a mixture of N-methylformamide (NMF) and diethylene glycol methyl ether (MDG) is the two solvents commonly used. When the stripping liquid is used, a large amount of stripping waste liquid is generated, and if the waste liquid is directly discharged, not only is serious pollution brought to the environment, but also great waste of resources is caused.

In the prior art, organic components in stripping liquid waste liquid are recovered in an evaporation or rectification mode, wherein the boiling point of NMF is 199 ℃, and the boiling point of MDG is 194 ℃. Because the boiling point of NMF and the boiling point of MDG are very close, the rectification separation needs large energy consumption, and the cost is also greatly increased. Chinese patent CN109970591A discloses a process for recovering high-purity N-methylformamide from waste stripping liquid, which is to rectify the stripping liquid of the waste N-methylformamide and diethylene glycol monomethyl ether to obtain NMF crude product with the mass concentration of 80-90%; and recycling for 1-3 times to perform melt crystallization, partial melting and melting, finally collecting the melt, and cooling and crystallizing to obtain the high-purity NMF. The waste liquid recovery method can obtain high-purity NMF, but causes a great deal of waste of MDG, and is not fully utilized. Meanwhile, the waste liquid contains a small amount of metal ions and suspended impurities which are not removed, so that the quality of the recovered product is influenced.

In addition to the above-mentioned methods, chinese patents CN102951761A and CN108840495A disclose recovery methods using vacuum rectification to obtain a directly usable stripping liquid, although the stripping liquid is mainly composed of a polar organic solvent, an amine and water. However, since the types of stripping solutions used by TFT-LCD companies are complicated and the components of the stripping waste liquid become very complicated, a recovery method of obtaining a stripping solution that can be directly used by rectification under reduced pressure would greatly increase the recovery cost, and it is difficult to popularize the method in actual production.

Disclosure of Invention

The invention aims to provide a method for recovering NMF and MDG from a photoresist stripping solution waste liquid, which has the advantages of simple flow and low cost and is suitable for large-scale popularization.

The invention adopts the following technical scheme:

a method for recovering NMF and MDG from a waste photoresist stripping solution comprises the following steps:

(1) filtering the waste photoresist stripping solution and then dehydrating;

(2) performing reduced pressure rectification on the dehydrated photoresist stripping liquid waste liquid to obtain a mixture of NMF and MDG and a high-boiling-point substance;

(3) electrolyzing the mixture of NMF and MDG to obtain a recovery solution of NMF and MDG;

(4) and (4) carrying out incineration treatment on the high-boiling-point substances.

Further, in the step (1), the filtered photoresist stripping solution waste liquid is dehydrated by using a dehydrating tower, wherein the tower top pressure of the dehydrating tower is set to be 10-12kPa, the tower top temperature is 50-75 ℃, and the tower kettle temperature is 70-100 ℃.

Preferably, the top pressure of the dehydrating tower is set to be 10kPa, the top temperature is 71 ℃, and the bottom temperature is 93 ℃.

Further, in the step (2), a refining tower is used for rectification under reduced pressure; the refining tower is a sieve plate tower, the pressure at the top of the tower is set to be 10-12kPa, the temperature at the top of the tower is 90-120 ℃, and the temperature at the bottom of the tower is 130-160 ℃.

Preferably, the pressure of the top of the refining tower is set to be 10kPa, the temperature of the top of the refining tower is 118 ℃, and the temperature of the bottom of the refining tower is 156 ℃.

Further, in the step (3), an electrolytic cell is adopted for electrolysis; the temperature of the electrolytic cell is 30-45 ℃, the distance between polar plates is 9-13mm, and the current density is 8-13mA/cm²Electrolyzing for 20-30min under the condition of (1).

Preferably, the temperature of the electrolytic cellThe distance between the polar plates is 9mm at the temperature of 35 ℃, and the current density is 8mA/cm²Electrolysis was carried out for 20min under the conditions of (1).

The device for the method for recovering the NMF and the MDG from the photoresist stripping liquid waste liquid comprises a waste liquid tank, wherein the waste liquid tank is connected with a dehydrating tower through a first connecting pipeline, the top of the dehydrating tower is connected with a pure water tank, the bottom of the dehydrating tower is connected with a refining tower through a second connecting pipeline, the top of the refining tower is connected with an electrolytic tank through a third connecting pipeline, the bottom of the refining tower is connected with a high-boiling-point material storage tank, and the electrolytic tank is connected with a recovery tank through a fourth connecting pipeline.

Further, centrifugal pumps are arranged on the first connecting pipeline, the second connecting pipeline, the third connecting pipeline and the fourth connecting pipeline.

The invention has the beneficial effects that: the device and the method of the invention can not only recover and obtain the mixed solution of NMF and MDG with high concentration, but also remove the metal ions and suspended impurities which affect the product quality, the product concentration can reach 99.4 percent, and the recovery rate can reach 95 percent to the maximum. Has the advantages of simple process and low cost. Is beneficial to industrialized large-scale popularization, and simultaneously greatly reduces the pollution of the stripping solution waste liquid to the environment.

Drawings

FIG. 1 is a schematic view of the apparatus of the present invention.

Wherein, 1 waste liquid tank, 2 first connecting pipeline, 3 dehydrating tower, 4 pure water tank, 5 second connecting pipeline, 6 refining tower, 7 third connecting pipeline, 8 electrolytic tank, 9 high boiling residue storage tank, 10 fourth connecting pipeline, 11 recovery tank, 12 centrifugal pump.

Detailed Description

The invention will now be further described with reference to specific examples which are intended to facilitate a better understanding of the present invention and are not intended to limit the scope of the claims appended hereto.

Waste liquid material: the waste liquid is obtained from Tianjin certain liquid crystal display manufacturing factory, and each index is shown in table 1, wherein the percentage represents the mass percentage content.

TABLE 1

。

In order to meet the process requirements and ensure that NMF has certain corrosivity, and considering the economic cost, the dehydration tower and the refining tower adopt sieve plate towers. According to the product purity requirement and the components of waste liquid materials (as shown in table 1), a DSTWU concise design module in ASPEN is used for obtaining a preliminary theoretical plate number, and Aspen plus is used for optimizing the flow to obtain parameters such as a tower plate number, a feeding plate position, a reflux ratio and the like. Under the condition of 10-12kPa of pressure, the number of the tower plates of the dehydration tower is 10-18, the 4 th to 6 th plates are fed with the material, and the reflux ratio is 1.5-3; the number of the tower plates of the refining tower is 12 to 18, the 3 rd to 5 th plates are fed, and the reflux ratio is 0.5 to 1.5.

The following examples 1 to 3 each treated the above waste liquid.

Example 1

A method for recovering NMF and MDG from a waste photoresist stripping solution comprises the following steps:

(1) and filtering the waste photoresist stripping solution and dehydrating.

And dehydrating the filtered photoresist stripping liquid waste liquid by using a dehydrating tower, wherein the dehydrating tower is a sieve plate tower with 10 tower plates, the 4 th plate is fed, the reflux ratio is 1.5, the pressure at the top of the tower is set to be 10kPa, the temperature at the top of the tower is 71 ℃, and the temperature at the bottom of the tower is 93 ℃.

(2) And (3) carrying out reduced pressure rectification on the dehydrated photoresist stripping liquid waste liquid to obtain a mixture of NMF and MDG and a high-boiling-point substance.

Carrying out vacuum rectification by using a refining tower; the refining tower is a sieve plate tower with 12 tower plates, the 3 rd plate is fed, the reflux ratio is 0.5, the tower top temperature is 118 ℃ and the tower bottom temperature is 156 ℃ under the condition of 10kPa, and the organic mixture of NMF and MDG is obtained by rectification and collection.

(3) And electrolyzing the mixture of the NMF and the MDG to obtain the recovery liquid of the NMF and the MDG.

Electrolyzing by adopting an electrolytic cell; the temperature of the electrolytic cell is 35 ℃, the distance between polar plates is 9mm, and the current density is 8mA/cm²Electrolysis was carried out for 20min under the conditions of (1).

(4) And sintering the high-boiling-point substance.

The concentration of the mixture of NMF and MDG recovered in the experiment is 99.4%, the chroma is less than 20 Hazen, the moisture content is less than 0.1wt%, and the metal ion content is less than 20 ppm. The recovery requirement is met, the recovery rate is 95 percent, and higher recovery rate is obtained.

Example 2

A method for recovering NMF and MDG from a waste photoresist stripping solution comprises the following steps:

(1) and filtering the waste photoresist stripping solution and dehydrating.

And dehydrating the filtered photoresist stripping liquid waste liquid by using a dehydrating tower, wherein the dehydrating tower is a sieve plate tower with 13 tower plates, the 5 th plate is fed, the reflux ratio is 3, the pressure at the top of the tower is set to be 12kPa, the temperature at the top of the tower is 72 ℃, and the temperature at the bottom of the tower is 95 ℃.

(2) And (3) carrying out reduced pressure rectification on the dehydrated photoresist stripping liquid waste liquid to obtain a mixture of NMF and MDG and a high-boiling-point substance.

Carrying out vacuum rectification by using a refining tower; the refining tower is a sieve plate tower with 15 tower plates, the 4 th plate is fed, the reflux ratio is 1, the pressure is 12kPa, the tower top temperature is 115 ℃, the temperature in the tower kettle is 141 ℃, and the organic mixture of NMF and MDG is obtained by rectification and collection.

(3) And electrolyzing the mixture of the NMF and the MDG to obtain the recovery liquid of the NMF and the MDG.

Electrolyzing by adopting an electrolytic cell; the temperature of the electrolytic cell is 41 ℃, the distance between the polar plates is 9mm, and the current density is 10mA/cm²Electrolysis was carried out for 25min under the conditions of (1).

(4) And (4) carrying out incineration treatment on the high-boiling-point substances.

The concentration of the recovered mixture of NMF and MDG is 99.1%, the moisture content is less than 0.1wt%, the metal ion content is less than 20ppm, and the chroma is less than 20 Hazen. The recovery rate is 91 percent according with the recovery requirement, and higher recovery rate is obtained.

Example 3

A method for recovering NMF and MDG from a waste photoresist stripping solution comprises the following steps:

(1) and filtering the waste photoresist stripping solution and dehydrating.

And dehydrating the filtered photoresist stripping liquid waste liquid by using a dehydrating tower, wherein the dehydrating tower is a sieve plate tower with 18 tower plates, the 6 th plate is fed, the reflux ratio is 2, the pressure at the top of the tower is set to be 11kPa, the temperature at the top of the tower is 65 ℃, and the temperature at the bottom of the tower is 91 ℃.

(2) And (3) carrying out reduced pressure rectification on the dehydrated photoresist stripping liquid waste liquid to obtain a mixture of NMF and MDG and a high-boiling-point substance.

Carrying out vacuum rectification by using a refining tower; the refining tower is a sieve plate tower with 18 tower plates, the 5 th plate is fed, the reflux ratio is 1.5, the tower top temperature is 110 ℃, the tower bottom temperature is 133 ℃ under the condition that the pressure is 11kPa, and the organic mixture of NMF and MDG is obtained by rectification and collection.

(3) And electrolyzing the mixture of the NMF and the MDG to obtain the recovery liquid of the NMF and the MDG.

Electrolyzing by adopting an electrolytic cell; the temperature of the electrolytic cell is 45 ℃, the distance between polar plates is 13mm, and the current density is 13mA/cm²And electrolyzing for 30min under the condition (1).

(4) And sintering the high-boiling-point substance.

The recovered mixture of NMF and MDG has a concentration of 99.2%, a chroma of less than 20 Hazen, a moisture content of less than 0.1wt%, and a metal ion content of less than 20 ppm. Meets the recovery requirement. The recovery rate is 93 percent, and the recovery rate is higher.

Example 4

The device for the method for recovering the NMF and the MDG from the waste photoresist stripping liquid comprises a waste liquid tank 1, wherein the waste liquid tank 1 is connected with a dehydrating tower 3 through a first connecting pipeline 2, the top of the dehydrating tower 3 is connected with a pure water tank 4, the bottom of the dehydrating tower 3 is connected with a refining tower 6 through a second connecting pipeline 5, the top of the refining tower 6 is connected with an electrolytic tank 8 through a third connecting pipeline 7, the bottom of the refining tower 6 is connected with a high-boiling-point material storage tank 9, and the electrolytic tank 8 is connected with a recovery tank 11 through a fourth connecting pipeline 10. Centrifugal pumps 12 are arranged on the first connecting pipeline 2, the second connecting pipeline 5, the third connecting pipeline 7 and the fourth connecting pipeline 10.

The above-mentioned embodiments are intended to explain the objects, aspects and effects of the present invention in further detail, and the above-mentioned description is only a preferred embodiment of the present invention, and is not intended to limit the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.