AU2020101985A4

AU2020101985A4 - A continuous lithium refining device and method for lithium containing materials

Info

Publication number: AU2020101985A4
Application number: AU2020101985A
Authority: AU
Inventors: Huimin Lu; Xiaoxi Lu
Original assignee: Beijing Oufei Jintai Technology Co Ltd
Current assignee: Beijing Oufei Jintai Technology Co Ltd
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2020-10-01
Anticipated expiration: 2028-08-25

Abstract

The invention provides a continuous lithium refining device and method for lithium containing materials, belonging to the field of resource utilization. The invention has the following technical effects. The induction heating device and graphite crucible are used for heating, which is fast and uniform and the reduction time is controlled within 2 hours after each feeding which saves the time; smooth feeding and discharging, the first reason of which is that the reduction chamber is vertical so it can always in the melting state and does not react with the reduction slag to cause adhesion, the second reason of which is that the slag is discharged quickly solving the problem of slag discharge in the shaft furnace, and the third reason of which is that feeding and discharging from the lower end is more convenient. -1/2 189 13 Figur 16

Description

-1/2

189

13 Figur 16

AUSTRALIA

PATENTS ACT 1990

PATENT SPECIFICATION FOR THE INVENTION ENTITLED:

A continuous lithium refining device and method for lithium containing materials

The invention is described in the following statement:-

A continuous lithium refining device and method for lithium containing

materials

TECHNICAL FIELD

The invention relates to the technical field of resource utilization, in particular to a

continuous lithium refining device and method for lithium containing materials.

BACKGROUND

At present, consumer electronic products represented by batteries, notebook computers

and mobile phones have strong demand for lithium batteries, which is the main driving

force for the growth of metal lithium demand. With the advancement and development of

science and technology, people's requirements for environmental protection are getting

higher and higher, which promotes the development of electric vehicles, electric bicycles,

and new energy vehicles. Pb-acid batteries are heavy, inconvenient and easy to cause

traffic accidents. Therefore, the replacement of lead-acid batteries by lithium batteries

will further accelerate in the future, especially the popularization of new energy vehicles,

which will greatly stimulate the demand for lithium batteries.

There are two main types of lithium in nature. One is in the form of lithium containing

ores such as spodumene, lepidolite, and permeate feldspar, and the other is in the form of

lithium ions in salt lake brines, underground brine and sea water. At present, the

mainstream process of industrial production of metal lithium is molten salt electrolysis

and vacuum reduction. The molten salt electrolysis method uses lithium chloride (LiCl)

as the raw material and potassium chloride as the electrolyte to play the role of stability, cooling and conductivity. The electrolysis temperature is about 450-500°C. The disadvantage of this method is that the lithium in the spodumene is first extracted into lithium carbonate and then converted into lithium chloride. The production cost is high.

For every ton of lithium produced, 5 tons of chlorine will be generated, which will

seriously pollute the air. The vacuum reduction method for lithium smelting also uses

lithium carbonate or lithium hydroxide monohydrate as raw materials, but the existing

vacuum reduction method for

lithium smelting equipment has the problems of incapability of continuous production

and low labour efficiency.

SUMMARY

In view of the above shortcomings, the purpose of the present invention is to provide a

continuous lithium refining device and method for lithium-containing materials.

The device provided by the invention can continuously produce, improve labour

efficiency and increase the service life of equipment. In order to achieve the above

mentioned purpose of the invention, the present invention provides the following

technical solutions.

The invention provides a continuous lithium refining device for lithium containing

materials, which includes a reduction chamber (1), graphite crucible (11), electrical

control system (4), vacuum unit (14), hydraulic system (12) and water cooling system

(13).

The bottom of the reduction chamber (1) is provided with an induction heating device (2),

which is connected with the heating power supply (3). The crucible lifting device (8) is arranged under the induction heating device (2), and the isolation valve 1 (16) is arranged between the induction heating device (2) and the crucible lifting device (8). The reduction chamber (1) is connected with a vacuum unit (14) through the isolation valve 5 (18), and the reduction chamber (1) is also connected with a crystallizer (17), which is connected with the metal lithium tank (21) through the isolation valve 6 (19), and the crystallizer

(17) is connected with the vacuum unit (14) through the isolation valve 7 (20).

The two sides of the crucible lifting device (8) are respectively provided with a feeding

chamber (5) and a discharging chamber (10). An isolation valve 4 (7) is arranged between

the crucible lifting device (8) and the feeding chamber (5); an isolation valve 3 (9) is

arranged between the crucible lifting device (8) and the discharge chamber (10); the

vacuum unit (14) is connected with the discharge chamber (10) through the isolation

valve 2 (15).

The graphite crucible (11) moves between the feeding chamber (5), the crucible lifting

device (8) and the discharge chamber (10) through a moving device (6).

The electrical control system (4) is respectively connected with reduction chamber (1),

feeding chamber (5), discharge chamber (10), crystallizer (17), isolation valve 1 (16),

isolation valve 2 (15), isolation valve 3 (9), isolation valve 4 (7), isolation valve 5 (18),

isolation valve 6 (19) and isolation valve 7(20). The electrical control system (4)

comprises a temperature measuring device and a vacuum detecting device to display

temperature and vacuum degree.

The hydraulic system (12) is connected with the crucible lifting device (8) to control the

lifting and falling of the crucible lifting device (8).

The water cooling system (13) is respectively connected with a reduction chamber (1),

induction heating device (2), vacuum unit (14) and crystallizer (17).

Preferably, the reduction chamber (1) has a double-layer water cooling structure.

Preferably, the metal lithium tank (21) contains liquid paraffin.

Preferably, a graphite filter is arranged in the crystallizer (17).

Preferably, the induction heating device (2) is an electromagnetic induction heating

device.

The invention also provides a continuous lithium refining method for lithium containing

materials. The device for continuous lithium refining with lithium containing materials

according to the technical scheme comprises the following steps.

Manually open the door of the feeding chamber (5), put the pellets made of lithium

containing materials, additives and reducing agents into the graphite crucible (11), and

close the door of the feeding chamber (5); open the isolation valve 4 (7) through the

electrical control system (4), and move the graphite crucible (11) to the crucible lifting

device (8) through the moving device (6); open the isolation valve 1 (16), lift the graphite

crucible (11) into the induction heating device (2) through the crucible lifting device (8);

open the vacuum unit (14) through the electrical control system (4), open the isolation

valve 2 (15) and isolation valve 3 (9), and vacuumize the discharge chamber (10) and the

feeding chamber (5); open the isolation valve 5 (18), the isolation valve 6 (19) and the

isolation valve 7 (20) to vacuumize reduction chamber (1), crystallizer (17) and metal

lithium tank (21); start water cooling system (13) to cool water into vacuum unit (14),

reduction chamber (1), crystallizer (17) and induction heating device (2); start heating

power supply (3) to heat induction heating device (2), and display vacuum degree and temperature in electrical control system (4) for reduction reaction, in which lithium is collected in the crystallizer (17) in liquid form and flows into the metal lithium tank (21).

After the reduction reaction is completed, the graphite crucible (11) is lowered through

the crucible lifting device (8), the isolation valve 1 (16) and the isolation valve 4 (7) are

closed, the moving device (6) enters the discharge chamber (10), the isolation valve 3 (9)

is closed, and the door of the discharge chamber (10) is opened to break the vacuum.

The hydraulic system (12) is connected with the crucible lifting device (8) and controls

the lifting and falling of the crucible lifting device (8).

Preferably, the temperature of the crystallizer (17) is 200 ~ 300 °C.

Preferably, when the lithium containing raw material is lithium carbonate or lithium

hydroxide monohydrate, the additive is a mixture of alumina and calcium oxide, and the

reducing agent is aluminium silicon alloy.

Preferably, when the lithium containing raw material is a lithium containing mineral, the

additive comprises a metal oxide, and the reducing agent comprises one or more of

aluminium, magnesium, silicon, calcium, calcium silicon alloy, aluminium magnesium

alloy, aluminium silicon alloy and silicon magnesium alloy.

Preferably, after the reduction reaction, the following steps are also included. Mixing the

lithium containing tailings obtained from the discharge chamber (10), reducing agent,

binder and water to form pellets, and the reducing agent includes bituminous coal and

petroleum coke; the pellet is subjected to reduction reaction to obtain aluminium silicon

calcium alloy liquid and dross, and the dross is a raw material for preparing metal lithium

and lithium extracted tailings from lithium containing materials; the aluminium silicon

calcium alloy liquid is mixed with refining agent to refine to obtain aluminium silicon calcium alloy; the aluminium silicon calcium alloy is distilled in vacuum to obtain metal calcium and aluminium silicon alloy.

The invention has the following technical effects:

(1) The induction heating device and graphite crucible are used for heating, which is

fast and uniform and the reduction time is controlled within 2 hours after each feeding

which saves the time.

(2) Smooth feeding and discharging. The first reason is that the reduction chamber is

vertical so it can always in the melting state and does not react with the reduction slag to

cause adhesion, the second reason is that the slag is discharged quickly solving the

problem of slag discharge in the shaft furnace, and the third reason is that feeding and

discharging from the lower end is more convenient.

(3) During the whole working process, the reduction chamber keeps a constant

temperature and does not break the vacuum, and can continuously produce, which

improves labour efficiency, so as to save energy and be environmental protection,

improve production efficiency, realize continuous production, and improve the service

life of equipment. At the same time, because the furnace is kept in vacuum, the purity of

lithium is high. Compared with the existing lithium extraction technologies, the current

efficiency is up to 90%, the recovery rate of lithium is more than 90%, and the purity of

lithium is as high as 99.9%.

Furthermore, the crystallizer is equipped with graphite filter and metal lithium tank, the

metal lithium is liquid, and the control temperature in crystallizer is 200 ~ 300 °C, and the

purity of lithium is high.

materials, realizing continuous lithium refining without solid waste discharge.

BRIEF DESCRIPTION OF THE FIGURES

Fig. 1 is the structural diagram of the continuous lithium refining device for lithium

containing materials of the present invention, wherein 1-reduction chamber, 2-induction

heating device, 3-heating power supply, 4-electrical control system, 5-feeding chamber,

6-moving device, 7-isolation valve 4, 8-crucible lifting device, 9-isolation valve 3, 10

discharge chamber, 11-graphite crucible, 12-hydraulic system, 13-water cooling system,

14-vacuum unit, 15-isolation valve 2, 16-isolation valve 1, 17-crystallizer, 18-isolation

valve 5, 19-isolation valve 6, 20 - isolation valve 7, 21 - metal lithium tank.

Fig. 2 is the flow chart of the method of continuous lithium refining without solid waste

with spodumene as lithium containing material in embodiment.

DESCRIPTION OF THE INVENTION

(13).

which is connected with the heating power supply (3). The crucible lifting device (8) is

arranged under the induction heating device (2), and the isolation valve 1 (16) is arranged

between the induction heating device (2) and the crucible lifting device (8). The reduction chamber (1) is connected with a vacuum unit (14) through the isolation valve 5 (18), and the reduction chamber (1) is also connected with a crystallizer (17), which is connected with the metal lithium tank (21) through the isolation valve 6 (19), and the crystallizer

(17) is connected with the vacuum unit (14) through the isolation valve 7 (20).

valve 2 (15).

device (8) and the discharge chamber (10) through a moving device (6).

temperature and vacuum degree.

lifting and falling of the crucible lifting device (8);

induction heating device (2), vacuum unit (14) and crystallizer (17).

valve 5, 19-isolation valve 6, 20 - isolation valve 7, 21 - metal lithium tank.

Preferably, the reduction chamber (1) of this invention has a double-layer water cooling

structure.

The metal lithium tank (21) contains liquid paraffin. The metal lithium tank (21) is

preferably removed from the crystallizer (17) regularly, connected to a glove box filled

with high purity argon, and then the valve of the lithium metal tank is opened to obtain

lithium ingot.

Preferably, a graphite filter is arranged in the crystallizer (17), which can filter dust, and

also plays a role in preventing temperature diffusion.

device.

according to the technical scheme comprises the following steps.

close the door of the feeding chamber (5); open the isolation valve 4 (7) through the electrical control system (4), and move the graphite crucible (11) to the crucible lifting device (8) through the moving device (6); Open the isolation valve 1 (16), lift the graphite crucible (11) into the induction heating device (2) through the crucible lifting device (8); open the vacuum unit (14) through the electrical control system (4), open the isolation valve 2 (15) and isolation valve 3 (9), and vacuumize the discharge chamber

(10) and the feeding chamber (5); open the isolation valve 5 (18), the isolation valve 6

(19) and the isolation valve 7 (20) to vacuumize reduction chamber (1), crystallizer (17)

and metal lithium tank (21); start water cooling system (13) to cool water into vacuum

unit (14), reduction chamber (1), crystallizer (17) and induction heating device (2); start

heating power supply (3) to heat induction heating device (2), and display vacuum degree

and temperature in electrical control system (4) for reduction reaction, in which lithium is

collected in the crystallizer (17) in liquid form and flows into the metal lithium tank (21).

the lifting and falling of the crucible lifting device (8).

reducing agent is aluminium silicon alloy.

The purity of the lithium carbonate and lithium hydroxide monohydrate is preferably

above 98%.

The purity of alumina and calcium oxide is better than 98%. The mass ratio of lithium

carbonate or lithium hydroxide monohydrate to alumina to calcium oxide is preferably 2

~ 3 to 1 ~ 1.5 to 1 ~ 1.5.

In the embodiment, it is preferred to mix the lithium carbonate or lithium hydroxide

monohydrate with the additive, calcine and grind them in turn, and then mix and press the

mixture, reducing agent and catalyst into pellets and put them into a graphite crucible

(11). In the embodiment, the roasting temperature is 750 ~ 850 °C and the time is 60 ~

100 minutes. The grinding is preferably ground to 60 mesh. In the embodiment, the

aluminium silicon alloy is preferably added in the form of powder, the particle size of the

powder is preferably 60 mesh, and the addition amount is 5-10% of the total mass of the

mixture of lithium carbonate or lithium hydroxide monohydrate and additive after

roasting.

In the embodiment, the catalyst is preferably CaF2, and the mass fraction of CaF2 in the

graphite crucible (11) is preferably 2-5%, more preferably 34%.

In the embodiment, the temperature of the reduction reaction is preferably 1100 ~

1200 °C, the vacuum degree is preferably 5 ~1OPa, and the time is preferably 1 ~ 2

hours.

The lithium obtained by the reduction reaction is collected in the crystallizer (17) in

liquid form and the temperature of the crystallizer (17) is preferably 200 ~ 300°C.

is closed, and the door of the discharge chamber (10) is opened to break the vacuum. In the embodiment, the lithium extraction tailings obtained by the reduction reaction preferably include CaO•7Al203(slag), 2CaO•SiO2 (slag), Cao (slag)•SiO2(slag) and

A1203•2SiO2, and the chemical composition is preferably calcium oxide 4050wt%,

alumina 4060wt%, silica 1530wt%, and the residue is other oxides.

Preferably, when the lithium containing material is a lithium containing mineral, the

alloy, aluminium silicon alloy and silicon magnesium alloy.

In the present embodiment, it is also preferred to put the catalyst CaF2 into a graphite

crucible (11) for reduction reaction, wherein, the mass fraction of catalyst CaF2 in the

graphite crucible (11) is preferably 2-5%, more preferably 34%.

In the present embodiment, the metal oxide active lime preferably comprises the

following components: Cao>95 wt%, SiO2<1.0 wt%,P<0.03 wt%, S<0.03 wt%.

In the embodiment, the lithium bearing mineral is preferably spodumene.

In the embodiment, the mass ratio of the lithium containing mineral to the additive to the

reducing agent is preferably (45 ~ 50) to (40 ~ 45) to (5 ~ 10).

In the present embodiment, the reduction reaction preferably includes a first reduction

and a second reduction in turn.

The temperature of the first reduction is preferably 500 ~ 700 °C, more preferably 550 ~

650 °C. The vacuum degree of the first reduction is preferably 1 ~ 50 Pa, more preferably

Pa ~ 45 Pa. The heating rate of heating to the temperature of the first reduction is

preferably 5 ~ 15 °C/min, more preferably 8 ~ 14 °C/min, and the holding time of the first

reduction is preferably 30 ~ 60 min, more preferably 40 ~ 50 min.

The temperature of the second reduction is preferably 1100 - 1300 °C, more preferably

1150 ~ 1250 °C, the vacuum degree of the second reduction is preferably 1000 ~ 1200pa,

more preferably 1050 - 1150pa, the heating rate rising to the temperature of the second

reduction is preferably 5 ~ 15 °C/min, more preferably 9 ~ 12 °C/min, and the holding

time of the second reduction is preferably 2.5 - 3h. In the embodiment, the holding time

of the second reduction can ensure that no lithium vapour is generated.

Taking spodumene as an example, in the present embodiment, adding catalyst, taking

metal oxide like calcium oxide as promoter, and aluminium silicon alloy as reducing

agent, the process of reduction reaction is as follows:

7[Li20-Al203-4SiO2] (spodumene) + 43CaO (promoter) +2[AlSi] (reducing

agent) = CaO-7Al203(slag)+14[2CaO-SiO2(slag)] + 14[Li](g) (lithium metal)

+ 14[CaO(s)-SiO2(s)] (slag) +[A1203-2SiO2] (slag)

The lithium obtained by the reduction reaction will be collected in the crystallizer (17) in

liquid form and crystallized.

In the invention, the temperature of the crystallizer (17) is preferably 200 - 300 °C.

In the embodiment, the lithium extracted tailings obtained by the reduction reaction

preferably include CaO•7Al203(slag), 2CaO•SiO2 (slag), Cao (slag)•SiO2(slag) and

A1203•2SiO2, and the chemical composition is preferably calcium oxide 3050wt%,

alumina 15-30wt%, silica 30-50wt%, and the residue is ferric oxide.

After the reduction reaction is completed, the lithium containing tailings obtained from

the discharge chamber (10) is preferably mixed with reducing agent, binder and water to

form pellets, and the reducing agents include bituminous coal and petroleum coke.

The pellets are reduced to obtain aluminium silicon calcium alloy liquid and dross, and

the dross is used as raw materials for preparing lithium metal and lithium extracted

tailings from lithium containing materials;

The aluminium silicon calcium alloy liquid is mixed with the refining agent for refining

to obtain the aluminium silicon calcium alloy which is subjected to vacuum distillation to

obtain metal calcium and aluminium silicon alloy.

The lithium containing tailings obtained from the discharge chamber (10) is mixed with

reducing agent, binder and water to form pellets, and the reducing agents include

bituminous coal and petroleum coke.

In the present embodiment, the pellet preferably comprises the following components by

weight: 50-65% of lithium tailings from lithium containing material, 20-40% of reducing

agent, 5-8% of binder and 4-6% of water, and the sum of mass percentage of each

component is 100%. The invention has no special limitation on the type of the binder, and

the binder type well known by the technical personnel in the art can be used.

The lithium extracted tailings of lithium containing material and reducing agent are

preferably grinded into powder with particle size less than 1 mm before using. the mass

ratio of bituminous coal to petroleum coke is preferably 8:2 ~ 6:4.

In the embodiment, the fixed carbon content of the bituminous coal is preferably 40 ~

%, and the fixed carbon content of the petroleum coke is preferably 80 ~ 90%. In the

present embodiment, the sum of the fixed carbon contents in the bituminous coal and petroleum coke is preferably 93-95% of the theoretical demand for complete reduction reaction. In the embodiment, the pelletizing is preferably made into pellets in a pelletizing machine, and the pelletizing pressure is preferably 20-30Mpa. The said pelletizing process preferably also includes drying, which is dehydrated at 100-200 °C until the mass percentage of water in the pellet is not more than 1%.

After the pellet is obtained, the pellet is subject to reduction reaction to obtain aluminium

silicon calcium alloy liquid and dross, and the dross is used for the lithium extracted

tailings of lithium containing material to prepare lithium metal additive.

In the embodiment, the temperature of the reduction reaction is preferably 1600 ~

1900 °C, more preferably 1550 ~ 1600 °C, and the time is preferably 2 ~ 3h. Since the

lithium extracted tailings of lithium containing material which contains a large amount of

calcium oxide is used, the reduction reaction temperature is low. In the embodiment, the

reduction reaction is preferably carried out in an AC or DC submerged arc furnace. The

output of the dross is preferably 2-5%, and the main components of the dross include 30

wt% calcium oxide, 15-30wt% alumina and 30-50wt% silica, and the residue is other

oxides

After the reduction reaction is completed, the aluminium silicon calcium alloy liquid is

preferably lifted and discharged from the aluminium outlet periodically and the interval is

preferably 2-3h.

After obtaining the aluminium silicon calcium alloy liquid, the aluminium silicon calcium

alloy liquid is mixed with the refining agent for refining to obtain the aluminium silicon

calcium alloy. In the embodiment, since the aluminium silicon calcium alloy liquid

contains a certain amount of non-metallic impurities, it is necessary to add refining agent in ladle lifting to remove slag. The invention has no special limitation on the type and amount of the refining agent, and the conventional technical means of a person skilled in the art can be used. The refining preferably includes vacuum filtering slag removal, mixing, diluting and ingot casting to obtain aluminium silicon calcium alloy, which preferably comprises the following components: aluminium 30 ~ 45wt%, silicon 20 ~ wt%, calcium 20 ~ 45wt%, and the rest are other elements contained in the raw materials which are refined into the aluminium silicon calcium alloy. After obtaining the aluminium silicon calcium alloy, it is subjected to vacuum distillation to obtain metal calcium and aluminium silicon alloy, wherein the vacuum degree is preferably 0.5 ~

Pa, the temperature is preferably 1000 ~ 1300 °C, and the time is preferably 2 ~ 5h. In

the embodiment, the aluminium silicon calcium alloy is preferably broken into pieces

with a particle size of less than 10 cm, and then put into a vacuum distillation tank for

vacuum distillation. After the vacuum distillation is completed, calcium is distilled out

and condensed into solid metal calcium, and the remaining material is aluminium silicon

alloy, which comprises the following components: aluminium 35 ~ 50wt%, silicon 40 ~

wt%, calcium 0.001% ~ 0.005wt%, and the rest are other elements contained in the

raw materials which are refined into the aluminium silicon calcium alloy. In the

embodiment, the aluminium silicon alloy is preferably reused as a reducing agent for

lithium containing materials to extract lithium.

The above are only the preferred embodiments of the present invention, and do not limit

the present invention in any form. It should be pointed out that for those of ordinary skill

in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A continuous lithium refining device for lithium containing materials is characterized

in that it comprises a reduction chamber (1), graphite crucible (11), electrical control

system (4), vacuum unit (14), hydraulic system (12) and water cooling system (13).

between the induction heating device (2) and the crucible lifting device (8). The reduction

chamber (1) is connected with a vacuum unit (14) through the isolation valve 5 (18), and

the reduction chamber (1) is also connected with a crystallizer (17), which is connected

with the metal lithium tank (21) through the isolation valve 6 (19), and the crystallizer

(17) is connected with the vacuum unit (14) through the isolation valve 7 (20).

valve 2 (15).

device (8) and the discharge chamber (10) through a moving device (6).

isolation valve 2 (15), isolation valve 3 (9), isolation valve 4 (7), isolation valve 5 (18), isolation valve 6 (19) and isolation valve 7(20). The electrical control system (4) comprises a temperature measuring device and a vacuum detecting device to display temperature and vacuum degree.

lifting and falling of the crucible lifting device (8).

induction heating device (2), vacuum unit (14) and crystallizer (17).

2. The continuous lithium refining device for lithium containing materials according to

claim 1 is characterized in that the reduction chamber (1) has a double-layer water

cooling structure.

3. The continuous lithium refining device for lithium containing materials according to

claim 1 is characterized in that the metal lithium tank (21) contains liquid paraffin.

4. The continuous lithium refining device for lithium containing materials according to

claim 1 is characterized in that a graphite filter is arranged in the crystallizer (17).

5. The continuous lithium smelting device for lithium containing materials according to

claim 1 is characterized in that the induction heating device (2) is an electromagnetic

induction heating device.

6. A continuous lithium smelting method for lithium containing materials according to

any one of claims 1 to 5 is characterized in that it comprises the following steps.

electrical control system (4), and move the graphite crucible (11) to the crucible lifting device (8) through the moving device (6); open the isolation valve 1 (16), lift the graphite crucible (11) into the induction heating device (2) through the crucible lifting device (8); open the vacuum unit (14) through the electrical control system (4), open the isolation valve 2 (15) and isolation valve 3 (9), and vacuumize the discharge chamber (10) and the feeding chamber (5); open the isolation valve 5 (18), the isolation valve 6 (19) and the isolation valve 7 (20) to vacuumize reduction chamber (1), crystallizer (17) and metal lithium tank (21); start water cooling system (13) to cool water into vacuum unit (14), reduction chamber (1), crystallizer (17) and induction heating device (2); start heating power supply (3) to heat induction heating device (2), and display vacuum degree and temperature in electrical control system (4) for reduction reaction, in which lithium is collected in the crystallizer (17) in liquid form and flows into the metal lithium tank (21).

the lifting and falling of the crucible lifting device (8).

7. The method according to claim 6 is characterized in that the temperature of the

crystallizer (17) is 200 ~ 300 °C.

8. The method according to claim 6 is characterized in that when the lithium containing

raw material is lithium carbonate or lithium hydroxide monohydrate, the additive is a

mixture of alumina and calcium oxide, and the reducing agent is aluminium silicon alloy.

9. The method according to claim 6 is characterized in that when the lithium containing

raw material is a lithium containing mineral, the additive comprises a metal oxide, and

the reducing agent comprises one or more of aluminium, magnesium, silicon, calcium,

calcium silicon alloy, aluminium magnesium alloy, aluminium silicon alloy and silicon

magnesium alloy.

10. The method according to claim 6 is characterized in that after the reduction reaction,

the following steps are also included. Mixing the lithium containing tailings obtained

from the discharge chamber (10), reducing agent, binder and water to form pellets, and

the reducing agent includes bituminous coal and petroleum coke; the pellet is subjected to

reduction reaction to obtain aluminium silicon calcium alloy liquid and dross, and the

dross is a raw material for preparing metal lithium and lithium extracted tailings from

lithium containing materials; the aluminium silicon calcium alloy liquid is mixed with

refining agent to refine to obtain aluminium silicon calcium alloy; the aluminium silicon

calcium alloy is distilled in vacuum to obtain metal calcium and aluminium silicon alloy

-1/2-

Figure 1

-2/2-

Figure 2