阅读说明：本技术 一种金属锂电解槽以及金属锂的制备方法 (Metal lithium electrolytic bath and preparation method of metal lithium ) 是由 洪侃 陈东英 李忠岐 徐建兵 梁鑫 赖耀斌 陈淑梅 张选旭 张积锴 王明 陈后兴 于 2020-07-16 设计创作，主要内容包括：本发明属于熔盐电解制备金属锂技术领域,提供了一种金属锂电解槽及金属锂的制备方法,本发明将石墨阳极从电解槽的顶部插入,置于阴极中间,有利于电流的均匀分布；采用隔膜将石墨阳极和阴极隔开,且在石墨阳极和隔膜之间设置氯气导出管,在隔膜和阴极之间设置导锂管,电解反应过程中,产生的氯气从氯气导出管抽出,金属锂则通过导锂管进入集锂室中,从而使氯气和金属锂分开,避免金属锂与氯气进行二次反应重新生成氯化锂,提高电流效率,降低电耗；进一步的,本发明提供的金属锂电解槽在加料仓底部设置一个可以打开的挡板,在加料时,可以先将氯化锂预热后再加入电解槽中,避免加料后熔盐温度波动过大。(The invention belongs to the technical field of metal lithium preparation by fused salt electrolysis, and provides a metal lithium electrolytic bath and a preparation method of metal lithium.A graphite anode is inserted from the top of the electrolytic bath and is arranged in the middle of a cathode, so that the uniform distribution of current is facilitated; the graphite anode and the cathode are separated by the diaphragm, the chlorine gas delivery pipe is arranged between the graphite anode and the diaphragm, the lithium delivery pipe is arranged between the diaphragm and the cathode, and the generated chlorine gas is pumped out from the chlorine gas delivery pipe in the electrolytic reaction process, and the metal lithium enters the lithium collection chamber through the lithium delivery pipe, so that the chlorine gas is separated from the metal lithium, the metal lithium is prevented from carrying out secondary reaction with the chlorine gas to regenerate lithium chloride, the current efficiency is improved, and the power consumption is reduced; furthermore, the metal lithium electrolytic cell provided by the invention is provided with the baffle which can be opened at the bottom of the charging bin, and during charging, lithium chloride can be preheated and then added into the electrolytic cell, so that the phenomenon that the temperature of molten salt fluctuates too much after charging is avoided.)

1. The metal lithium electrolytic cell is characterized by comprising a cavity; the interior of the cavity is divided into an electrolysis chamber and a lithium collecting chamber;

a graphite anode disposed in the center of the electrolytic cell;

a separator surrounding the outside of the graphite anode;

a cathode surrounding an outer side of the separator;

a chlorine gas delivery pipe is arranged between the graphite anode and the diaphragm;

a lithium guide pipe is arranged between the diaphragm and the cathode and is communicated with the lithium collecting chamber;

the top of the cavity is provided with a cavity cover, and the cavity cover is provided with a feeding bin and an observation hole; the top end of the graphite anode extends out of the top of the cavity cover;

the outer surface of the cavity is also sequentially provided with a heating resistance plate, a refractory insulating brick and an outer protective shell.

2. The lithium metal electrolyte cell of claim 1 further comprising an anode clamp; the anode clamp is clamped to the portion of the graphite anode that protrudes from the top of the chamber cover.

3. The metal lithium electrolytic cell of claim 1, wherein the feed inlet of the feed bin is a beveled opening; the bottom of the feeding bin is provided with an openable baffle.

4. The metal lithium electrolytic cell of claim 1, wherein a lithium extraction tube is further disposed within the lithium collection chamber.

5. The metal lithium electrolytic cell according to claim 1, wherein the distance between the graphite anode and the separator is 20-40 mm; the distance between the diaphragm and the cathode is 50-80 mm.

6. The metal lithium electrolytic cell according to claim 1, wherein the length of the part of the graphite anode protruding from the top of the chamber cover is 150-200 mm.

7. The metal lithium electrolytic cell according to claim 1, wherein the surface of the diaphragm is provided with small holes, the aperture ratio of the diaphragm is 5-9%, and the diameter of each small hole is 0.07-1 mm.

8. A method for preparing metallic lithium by using the metallic lithium electrolytic cell of any one of claims 1 to 7, which is characterized by comprising the following steps:

(1) adding a mixture of lithium chloride and potassium chloride into a metal lithium electrolytic bath, and starting a heating resistance plate to melt the lithium chloride and the potassium chloride to form a molten salt;

(2) the electrolytic cell is electrified to carry out electrolysis, chlorine generated by electrolysis is extracted through the chlorine delivery pipe, and lithium metal generated by electrolysis enters the lithium collection chamber from the lithium delivery pipe.

9. The method according to claim 8, wherein the temperature of the electrolysis is 400 to 440 ℃ and the current is 600 to 1000A.

10. The method as claimed in claim 8, wherein during the electrolysis, the electrolytic cell is replenished with lithium chloride from a feed bin, the lithium chloride is preheated in the feed bin, and then the preheated lithium chloride is fed into the electrolytic cell by opening the baffle plate.

Technical Field

The invention belongs to the technical field of metal lithium preparation through molten salt electrolysis, and particularly relates to a metal lithium electrolytic bath and a preparation method of metal lithium.

Background

The preparation of metallic lithium by lithium chloride molten salt electrolysis is the main technical method for industrially preparing metallic lithium at present, and about 90 percent of metallic lithium is prepared by the method. There are many kinds of designs in the fused salt electrolysis trough at home and abroad, insert formula steel negative pole and side and insert formula graphite anode under adopting generally, separate the negative and positive pole product with the steel baffle, use pottery or graphite to make the groove lining, adopt the manual mode of scooping up lithium to get lithium, metal lithium easily reacts with oxygen in the air, nitrogen, reduce product purity to chlorine easily reacts with metal lithium secondary and regenerates the lithium chloride among the electrolysis process, leads to the electrolytic efficiency low.

Disclosure of Invention

In view of the above, the present invention provides a metal lithium electrolytic bath and a method for preparing metal lithium. The metal lithium electrolytic cell provided by the invention has high electrolytic efficiency and high product purity.

In order to achieve the above object, the present invention provides the following technical solutions:

a metal lithium electrolytic cell comprises a cavity; the interior of the cavity is divided into an electrolysis chamber and a lithium collecting chamber;

a graphite anode disposed in the center of the electrolytic cell;

a separator surrounding the outside of the graphite anode;

a cathode surrounding an outer side of the separator;

a chlorine gas delivery pipe is arranged between the graphite anode and the diaphragm;

a lithium guide pipe is arranged between the diaphragm and the cathode and is communicated with the lithium collecting chamber;

the top of the cavity is provided with a cavity cover, and the cavity cover is provided with a feeding bin and an observation hole; the top end of the graphite anode extends out of the top of the cavity cover;

the outer surface of the cavity is also sequentially provided with a heating resistance plate, a refractory insulating brick and an outer protective shell.

Preferably, the metallic lithium electrolytic cell further comprises an anode clamp; the anode clamp is clamped to the portion of the graphite anode that protrudes from the top of the chamber cover.

Preferably, the feed inlet of the feeding bin is an inclined opening; the bottom of the feeding bin is provided with an openable baffle.

Preferably, a lithium extraction pipe is further arranged in the lithium collection chamber.

Preferably, the distance between the graphite anode and the diaphragm is 20-40 mm; the distance between the diaphragm and the cathode is 50-80 mm.

Preferably, the length of the part of the graphite anode extending out of the top of the cavity cover is 150-200 mm.

Preferably, the surface of the diaphragm is provided with small holes, the aperture ratio of the diaphragm is 5-9%, and the aperture of each small hole is 0.07-1 mm.

The invention also provides a method for preparing the metal lithium by using the metal lithium electrolytic bath, which comprises the following steps:

(1) adding a mixture of lithium chloride and potassium chloride into a metal lithium electrolytic bath, and starting a heating resistance plate to melt the lithium chloride and the potassium chloride to form a molten salt;

(2) the electrolytic cell is electrified to carry out electrolysis, chlorine generated by electrolysis is extracted through the chlorine delivery pipe, and lithium metal generated by electrolysis enters the lithium collection chamber from the lithium delivery pipe.

Preferably, the electrolysis temperature is 400-440 ℃, and the current is 600-1000A.

Preferably, in the electrolysis process, lithium chloride is supplemented into the electrolytic cell from the feeding bin, the lithium chloride is preheated in the feeding bin, and then the preheated lithium chloride is added into the electrolytic cell by opening the baffle.

The invention provides a metal lithium electrolytic cell, wherein a graphite anode is designed into a top-inserted type, is inserted from the top of the electrolytic cell and is arranged in the middle of a cathode, so that the uniform distribution of current is facilitated; in addition, the graphite anode and the graphite cathode are separated by the diaphragm, the chlorine gas delivery pipe is arranged between the anode and the diaphragm, the lithium delivery pipe is arranged between the diaphragm and the cathode, the generated chlorine gas is pumped out from the chlorine gas delivery pipe in the electrolytic reaction process, and the metal lithium enters the lithium collection chamber through the lithium delivery pipe; and the lithium metal is pumped out by the lithium pumping pipe after entering the lithium collecting chamber, so that the reaction of the lithium metal and oxygen and nitrogen in the air can be avoided, and the product purity is improved.

In addition, in the field, the lithium chloride raw material is generally directly added into the electrolytic cell in the electrolytic process of the metal lithium, and the temperature difference between the added lithium chloride raw material and the molten salt in the electrolytic cell is large, so that the temperature fluctuation of the molten salt in the electrolytic cell is large, the molten salt is locally hardened, and the electrolysis is influenced.

Drawings

FIG. 1 is a schematic structural diagram of a metallic lithium electrolytic cell;

FIG. 2 is a top view of a metallic lithium electrolytic cell;

in FIGS. 1 to 2: 1-graphite anode, 2-anode clamp, 3-cavity cover, 4-diaphragm, 5-cathode, 6-cavity, 7-heating resistance plate, 8-outer protective shell, 9-chlorine gas outlet pipe, 10-lithium guide pipe, 11-fire-resistant insulating brick, 12-lithium extraction pipe, 13-lithium collection chamber, 14-electrolysis chamber, 15-baffle, 16-observation hole, 17-feeding bin and 18-cathode hanger.

The results of the examples show that the current efficiency of electrolysis can reach 85.31% and the purity of the metallic lithium can reach 98.57% when the metallic lithium electrolytic cell of the invention is used for preparing the metallic lithium.