阅读说明：本技术 一种锂离子电池隔膜生产设备流出白油的回收再生方法 (Method for recycling white oil flowing out of lithium ion battery diaphragm production equipment ) 是由 袁海朝 徐锋 解悦 于 2019-09-29 设计创作，主要内容包括：本发明公开了一种锂离子电池隔膜生产设备流出白油的回收再生方法,常温下,使用纤维素纤维助滤剂,经过板式压滤机进行液固分离,超高分子聚乙烯杂质最高脱除率为99.5％；常温下,使用凹凸棒土脱色砂进行脱色；使用聚丙烯酸钠吸水纤维除水,节约能耗,降低成本。过滤出白油按照NAS 1638的标椎等级为5和新白油一致。(The invention discloses a method for recycling white oil flowing out of lithium ion battery diaphragm production equipment, which comprises the following steps of performing liquid-solid separation by using a cellulose fiber filter aid through a plate filter press at normal temperature, wherein the highest removal rate of ultrahigh molecular weight polyethylene impurities is 99.5%; at normal temperature, using attapulgite decolorizing sand to decolorize; the sodium polyacrylate water-absorbing fiber is used for removing water, so that the energy consumption is saved, and the cost is reduced. The white oil filtered was consistent with the new white oil according to standard cone rating of NAS1638 of 5.)

1. A method for recycling white oil flowing out of lithium ion battery diaphragm production equipment is characterized by comprising the following steps:

step 1, adding 0.1-0.2 wt% of cellulose fiber filter aid into white oil flowing out of lithium ion battery diaphragm production equipment, stirring, and filtering by using a filter to obtain filtered white oil;

the water content in the white oil flowing out of the lithium ion battery diaphragm production equipment is 0.1-0.5 wt%, and the content of the ultra-high molecular weight polyethylene is 100-1000 ppm;

the cellulose fiber filter aid is a short fiber column with the diameter of 15-20 micrometers and the length of 50-100 micrometers;

step 2, adopting attapulgite decolorizing sand to decolorize the filtered white oil to obtain decolorized white oil;

the particle size of the attapulgite decolorized sand is 30-80 meshes;

step 3, dehydrating the decolored white oil by adopting sodium polyacrylate water-absorbing fibers to obtain dehydrated white oil;

step 4, filtering the dehydrated white oil by using a precision filter to obtain regenerated white oil;

and a polytetrafluoroethylene filter element is arranged in the precision filter.

2. The recycling method according to claim 1, wherein in the step 1, the filter is a plate and frame filter press.

3. The recycling and regenerating method according to claim 1, characterized in that in the step 1, the stirring time is 0.5 to 1 hour.

4. The recycling and regenerating method according to claim 1, characterized in that in the step 2, the decoloring process is performed in a decoloring sand tank, and four layers of attapulgite decoloring sand with a grain size of 30 to 80 meshes are arranged in the decoloring sand tank.

5. The recycling method according to claim 1, wherein the decolorizing sand tank has a height to diameter ratio of 2: 1.

6. The recycling method according to claim 4, wherein only the uppermost attapulgite-colored sand is replaced at each replacement.

7. The recycling method according to claim 1, wherein the sodium polyacrylate water-absorbing fiber has a water absorption capacity of 150.

8. The recycling method according to claim 1, wherein the sodium polyacrylate water-absorbing fiber is dried and recycled at 110 ℃ after use.

9. The recycling and regenerating method according to claim 1, characterized in that a polytetrafluoroethylene filter element with a pore size of 0.1-0.5 microns is arranged in the precision filter.

10. A method for recycling white oil flowing out of lithium ion battery diaphragm production equipment is characterized by comprising the following steps:

step 1, adding 0.2 wt% of cellulose fiber filter aid into white oil flowing out of the lithium ion battery diaphragm production equipment, stirring for 0.5h, and then filtering by adopting a plate-and-frame filter press to obtain filtered white oil;

the water content in the white oil flowing out of the lithium ion battery diaphragm production equipment is 0.1-0.5 wt%, and the content of the ultra-high molecular weight polyethylene is 100-1000 ppm;

the cellulose fiber filter aid is a short fiber column with the diameter of 15-20 micrometers and the length of 50-100 micrometers;

step 2, decoloring the filtered white oil by using a decoloring sand tank, wherein four layers of attapulgite decoloring sand with the particle size of 60-80 meshes are arranged in the decoloring sand tank to obtain the decolored white oil, and the height-diameter ratio of the decoloring sand tank is 2: 1;

step 3, dehydrating the decolored white oil by adopting sodium polyacrylate water-absorbing fibers to obtain dehydrated white oil;

the water absorption multiplying power of the sodium polyacrylate water absorption fiber is 150;

step 4, filtering the dehydrated white oil by using a precision filter to obtain regenerated white oil;

and a polytetrafluoroethylene filter element with the pore diameter of 0.1 micron is arranged in the precision filter.

Technical Field

The invention belongs to the technical field of resource recycling, and particularly relates to a method for recycling white oil flowing out of lithium ion battery diaphragm production equipment.

Background

In the production of the lithium battery diaphragm, the ultrahigh molecular weight polyethylene is used as a raw material, the white oil is used as a pore-forming agent, and the production process comprises the following steps: heating and stirring white oil and ultrahigh molecular polyethylene, passing through an extruder to generate a cast sheet, and stretching the cast sheet into an ultrahigh molecular polyethylene diaphragm by a stretcher. In the process, 10-15% of white oil flows from the cast sheet and the diaphragm to the oil receiving disc and the drawing machine. The white oil flowing out of the production equipment contains 0.1-0.5% of water and 100-1000 ppm of ultra-high molecular weight polyethylene, and is yellowish.

In the prior art of recycling white oil discharged from production equipment, the following two methods are generally used for removing impurities of the ultra-high molecular weight polyethylene: 1. a flocculating agent is used, and the flocculating agent is added into white oil flowing out of production equipment, wherein the highest removal rate of ultrahigh molecular weight polyethylene impurities in the white oil is 90%; the defect is that the recovery rate of the white oil is only 95 percent, and the rest 5 percent of white oil is mixed with the flocculating agent and can not be recovered; 2. the highest removal rate of the ultrahigh molecular polyethylene impurities in the white oil is 99 percent by using a 1 micron bag filter for filtration, but the service life of a filter bag is short and the filter bag is unreasonable in economy; and the filtering temperature of the ultrahigh molecular weight polyethylene impurities in the white oil exceeds 80 ℃, and the ultrahigh molecular weight polyethylene can be dissolved in the white oil, so that the filtering and separating are difficult.

In the prior art of recovering and treating white oil flowing out of production equipment, a powdery activated clay decolorization process is usually adopted for decolorization treatment, the white oil needs to be heated to 80-100 ℃, the white oil temperature of the separated white clay is 60-80 ℃, and the white oil needs to be cooled to prevent oxidation of the white oil, so that the process is complex and the treatment cost is high.

In the prior art of recovering and treating white oil flowing out of production equipment, the dehydration of the white oil is performed by methods such as centrifugal separation, precipitation separation, distillation and the like, and the conditions of high energy consumption and high cost exist.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a method for recovering and regenerating white oil flowing out of lithium ion battery diaphragm production equipment, wherein at normal temperature, a cellulose fiber filter aid is used, liquid-solid separation is carried out by a plate filter press, and the highest removal rate of ultra-high molecular weight polyethylene impurities is 99.5%; at normal temperature, using attapulgite decolorizing sand to decolorize; the sodium polyacrylate water-absorbing fiber is used for removing water, so that the energy consumption is saved, and the cost is reduced.

The invention is realized by the following technical scheme:

a method for recycling white oil flowing out of lithium ion battery diaphragm production equipment comprises the following steps:

step 1, adding 0.1-0.2 wt% of cellulose fiber filter aid into white oil flowing out of lithium ion battery diaphragm production equipment, stirring, and filtering by using a filter to obtain filtered white oil;

the water content in the white oil flowing out of the lithium ion battery diaphragm production equipment is 0.1-0.5 wt%, and the content of the ultra-high molecular weight polyethylene is 100-1000 ppm;

the cellulose fiber filter aid is a short fiber column with the diameter of 15-20 micrometers and the length of 50-100 micrometers;

step 2, adopting attapulgite decolorizing sand to decolorize the filtered white oil to obtain decolorized white oil;

the particle size of the attapulgite decolorized sand is 30-80 meshes;

step 3, dehydrating the decolored white oil by adopting sodium polyacrylate water-absorbing fibers to obtain dehydrated white oil;

step 4, filtering the dehydrated white oil by using a precision filter to obtain regenerated white oil;

and a polytetrafluoroethylene filter element is arranged in the precision filter.

In the above technical scheme, in the step 1, the filter is a plate and frame filter press.

In the technical scheme, in the step 1, the stirring time is 0.5-1 hour.

In the technical scheme, in the step 2, the decoloring process is carried out in a decoloring sand tank, and four layers of attapulgite decoloring sand with the grain diameter of 30-80 meshes are arranged in the decoloring sand tank.

In the technical scheme, the height-diameter ratio of the decolorizing sand tank is 2: 1.

In the technical scheme, the water absorption rate of the sodium polyacrylate water absorption fiber is 150;

in the technical scheme, the sodium polyacrylate water-absorbing fiber is dried and regenerated at 110 ℃ after being used.

In the technical scheme, the precision filter is internally provided with a polytetrafluoroethylene filter element with the aperture of 0.1-0.5 micron.

A method for recycling white oil flowing out of lithium ion battery diaphragm production equipment comprises the following steps:

step 1, adding 0.2 wt% of cellulose fiber filter aid into white oil flowing out of the lithium ion battery diaphragm production equipment, stirring for 0.5h, and then filtering by adopting a plate-and-frame filter press to obtain filtered white oil;

the water content in the white oil flowing out of the lithium ion battery diaphragm production equipment is 0.1-0.5 wt%, and the content of the ultra-high molecular weight polyethylene is 100-1000 ppm;

the cellulose fiber filter aid is a short fiber column with the diameter of 15-20 micrometers and the length of 50-100 micrometers;

step 2, decoloring the filtered white oil by using a decoloring sand tank, wherein four layers of attapulgite decoloring sand with the particle size of 60-80 meshes are arranged in the decoloring sand tank to obtain the decolored white oil, and the height-diameter ratio of the decoloring sand tank is 2: 1;

step 3, dehydrating the decolored white oil by adopting sodium polyacrylate water-absorbing fibers to obtain dehydrated white oil;

the water absorption multiplying power of the sodium polyacrylate water absorption fiber is 150;

step 4, filtering the dehydrated white oil by using a precision filter to obtain regenerated white oil;

and a polytetrafluoroethylene filter element with the pore diameter of 0.1 micron is arranged in the precision filter.

The invention has the advantages and beneficial effects that:

the invention relates to a white oil treatment process containing ultra-high molecular weight polyethylene impurities and water, which uses cellulose fiber filter aid to carry out liquid-solid separation by a plate filter press at normal temperature, wherein the highest removal rate of the ultra-high molecular weight polyethylene impurities is 99.5 percent; at normal temperature, using attapulgite decolorizing sand to decolorize; the sodium polyacrylate water-absorbing fiber is used for removing water, so that the energy consumption is saved, and the cost is reduced.

The cellulose fiber filter aid is a short fiber column with the diameter of 15-20 microns and the length of 50-100 microns, has a certain electrostatic adsorption effect, can adsorb ultrahigh molecular polyethylene impurities, and improves the filtration precision; the attapulgite dehydrated sand used as a decoloring agent is generally integrally arranged in a dehydration tank, and is completely replaced during replacement, and actually, the bottom decolored sand also has decoloring capacity and great waste; the polytetrafluoroethylene filter element with the aperture of 0.1 micron is used for precise filtration, the filtered white oil is consistent with new white oil according to the standard cone grade of NAS1638 (see table 1), all processes are carried out at normal temperature, the energy consumption is low, and the filtration effect is good.

Drawings

FIG. 1 is a schematic flow chart of a process for regenerating spent alkaline clay containing white oil.

For a person skilled in the art, other relevant figures can be obtained from the above figures without inventive effort.

Detailed Description

In order to make the technical solution of the present invention better understood, the technical solution of the present invention is further described below with reference to specific examples.