Micronized lithium oxide and a method for its production

Abstract

The application belongs to the technical field of oxide preparation, and discloses a micro-powder lithium oxide and a preparation method thereof, the preparation method comprising the following steps: after metal lithium is heated and melted, the metal lithium is subjected to oxygen blowing and an oxidation reaction to obtain lithium oxide droplets; the lithium oxide droplets are cooled, and then are sequentially subjected to separation and screening to obtain the micro-powder lithium oxide. The micro-powder lithium oxide obtained by the application has the characteristics of small particle size, high purity and high yield.

Description

Technical Field

[0001] This invention relates to the field of oxide preparation technology, and in particular to a micronized lithium oxide and its preparation method. Background Technology

[0002] Lithium oxide is a high-performance non-aqueous electrolyte. Batteries made from it not only possess the characteristics of general lithium batteries but also offer advantages such as low cost and zero pollution. Besides its significant applications in lithium batteries, lithium oxide is used as an additive in the glass industry to improve glass properties. Furthermore, lithium oxide is used in the preparation of specialty glasses and lithium compounds, as well as in nuclear fusion reactors.

[0003] Currently, the industrial production of battery-grade lithium oxide mainly uses metallic lithium as raw material and adopts the combustion method. The process involves oxidation and calcination, screening, ball milling, and sieving to obtain battery-grade lithium oxide. However, the ball milling and sieving processes are mainly carried out using semi-mechanized operations, which have problems such as poor equipment sealing, large dust emissions, easy moisture absorption of products, low yield, and environmental unfriendliness, as well as a heavy workload for operators in the production site.

[0004] Therefore, it is of great significance to develop a preparation method that can improve the yield and purity of lithium oxide products. Summary of the Invention

[0005] In view of this, the present invention provides a micronized lithium oxide and its preparation method, the purpose of which is to solve the problems of low efficiency and low purity in the preparation of lithium oxide by existing processes.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] This invention provides a method for preparing micronized lithium oxide, comprising the following steps:

[0008] 1) After heating and melting lithium metal, it is oxidized by blowing oxygen to obtain lithium oxide droplets;

[0009] 2) After cooling the lithium oxide droplets, they were separated and sieved sequentially to obtain micronized lithium oxide.

[0010] Preferably, the purity of the lithium metal is ≥99.9%.

[0011] Preferably, the heating and melting are carried out under vacuum, and the vacuum degree is ≤1×10⁻⁶. -1 Pa.

[0012] Preferably, the heating and melting temperature is 390–410°C, and the heating and melting time is 50–70 min.

[0013] Preferably, the purity of the oxygen is ≥99.99%.

[0014] Preferably, the pressure of the gas being sprayed is ≥4MPa.

[0015] Preferably, the cooling temperature is ≤25℃, and the cooling medium is white oil.

[0016] Preferably, the separation is a multi-stage cyclone separation.

[0017] The present invention also provides micronized lithium oxide obtained by the aforementioned method for preparing micronized lithium oxide.

[0018] Preferably, the D90 of the micronized lithium oxide is 60-80 μm.

[0019] As can be seen from the above technical solution, compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] 1) The heating and melting described in this invention is carried out in a vacuum environment, which avoids the introduction of impurities and results in higher purity lithium oxide. At the same time, only the reaction between metallic lithium and oxygen occurs, without producing other by-products, and the yield is higher.

[0021] 2) This invention uses gas atomization to prepare lithium oxide powder, which eliminates the need for ball milling, simplifies the preparation process, saves labor, and avoids the problem of introducing impurities during ball milling, thereby improving the purity and yield of lithium oxide. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0023] Figure 1 This is a process flow diagram of the method for preparing micronized lithium oxide according to the present invention;

[0024] Figure 2 This is a particle size distribution diagram of the micronized lithium oxide obtained in Example 3. Detailed Implementation

[0025] This invention provides a method for preparing micronized lithium oxide, comprising the following steps:

[0026] 1) After heating and melting lithium metal, it is oxidized by blowing oxygen to obtain lithium oxide droplets;

[0027] 2) After cooling the lithium oxide droplets, they were separated and sieved sequentially to obtain micronized lithium oxide.

[0028] In this invention, the purity of the lithium metal is preferably ≥99.9%, and more preferably ≥99.99%.

[0029] In this invention, the heating and melting are carried out under vacuum, and the vacuum level is preferably ≤1×10⁻⁶. -1 Pa, more preferably ≤5×10 -2 Pa, more preferably ≤3×10 -2 Pa.

[0030] In this invention, the heating and melting temperature is preferably 390-410°C, more preferably 395-405°C, and even more preferably 398-402°C. The heating and melting time is preferably 50-70 min, more preferably 55-65 min, and even more preferably 58-62 min.

[0031] In this invention, the blowing is preferably carried out in a spray disc, which contains an angle-adjustable nozzle. The angle of the nozzle is preferably 0 to 80°, more preferably 30 to 60°, and even more preferably 40 to 50°.

[0032] In this invention, the heated and molten lithium metal flows to the spray plate through a guide nozzle. The temperature of the guide nozzle is preferably ≥250℃, more preferably ≥300℃, and even more preferably ≥320℃.

[0033] In this invention, the purity of the oxygen is preferably ≥99.99%, and more preferably ≥99.999%.

[0034] In this invention, the pressure of the gas being sprayed is preferably ≥4MPa, more preferably 4-6MPa, and even more preferably 4.5-5.5MPa.

[0035] In this invention, the cooling temperature is preferably ≤25℃, more preferably ≤23℃, and even more preferably ≤20℃, and the cooling medium is preferably white oil.

[0036] In this invention, the white oil is preferably cosmetic grade white oil.

[0037] In this invention, the separation is preferably a multi-stage cyclone separation.

[0038] In this invention, the separated products are preferably screened after separation, and the screening is preferably carried out using a vibrating screen.

[0039] The present invention also provides micronized lithium oxide obtained by the aforementioned method for preparing micronized lithium oxide.

[0040] In this invention, the D90 of the micronized lithium oxide is preferably 60-80 μm, more preferably 63-78 μm, and even more preferably 65-70 μm.

[0041] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0042] Example 1

[0043] Add 5 kg of 99.99% pure lithium metal to a stainless steel crucible and evacuate to a vacuum of 5 × 10⁻⁶. -2 Pa was heated at 400°C for 60 min to obtain fully molten metallic lithium.

[0044] Adjust the nozzle angle of the spray disc to 45°, introduce oxygen with a purity of 99.99% at a pressure of 4MPa, open the guide nozzle valve, lift the metal plug rod at the bottom of the stainless steel crucible, and let the liquid lithium metal flow into the spray disc through the 300°C guide nozzle. It is broken and atomized by oxygen spraying. The broken liquid lithium metal reacts with oxygen to produce lithium oxide droplets.

[0045] Lithium oxide droplets are passed into a cooling chamber containing cosmetic-grade white oil as the cooling medium and cooled to 25°C to obtain lithium oxide powder. The lithium oxide powder is then subjected to multi-stage cyclone separation by an induced draft fan and enters a collection tank. The lithium oxide powder in the collection tank is then sieved through a vibrating screen to obtain micronized lithium oxide.

[0046] The mass of the micronized lithium oxide obtained in this embodiment is 10.809 kg, the purity of the micronized lithium oxide is 99.281%, and the particle size is D10 = 5.323 μm, D50 = 30.210 μm, and D90 = 78.862 μm.

[0047] Example 2

[0048] Add 5 kg of 99.99% pure lithium metal to a stainless steel crucible and evacuate to a vacuum of 3 × 10⁻⁶. -2 Pa was heated at 410°C for 55 min to obtain fully molten metallic lithium.

[0049] Adjust the nozzle angle of the spray disc to 45°, introduce oxygen with a purity of 99.99% at a pressure of 5MPa, open the guide nozzle valve, lift the metal plug rod at the bottom of the stainless steel crucible, and let the liquid lithium metal flow into the spray disc through the 250°C guide nozzle. It is broken and atomized by oxygen spraying. The broken liquid lithium metal reacts with oxygen to produce lithium oxide droplets.

[0050] Lithium oxide droplets are passed into a cooling chamber containing cosmetic-grade white oil as the cooling medium and cooled to 23°C to obtain lithium oxide powder. The lithium oxide powder undergoes multi-stage cyclone separation in an induced draft fan and then enters a collection tank. The lithium oxide powder in the collection tank is sieved through a vibrating screen to obtain micronized lithium oxide.

[0051] The mass of the micronized lithium oxide obtained in this embodiment is 10.803 kg, the purity of the micronized lithium oxide is 99.374%, and the particle size is D10 = 4.805 μm, D50 = 25.201 μm, and D90 = 64.745 μm.

[0052] Example 3

[0053] Add 8 kg of 99.99% pure lithium metal to a titanium crucible and evacuate to a vacuum of 8 × 10⁻⁸. -3 Pa was heated at 395°C for 65 min to obtain fully molten metallic lithium.

[0054] Adjust the nozzle angle of the spray disc to 45°, introduce oxygen with a purity of 99.99% at a pressure of 5MPa, open the guide valve, lift the metal plug rod at the bottom of the titanium crucible, and let the liquid lithium metal flow into the spray disc through the 350°C guide nozzle. It is broken and atomized by oxygen spraying. The broken liquid lithium metal reacts with oxygen to produce lithium oxide droplets.

[0055] Lithium oxide droplets are passed into a cooling chamber containing cosmetic-grade white oil as the cooling medium and cooled to 25°C to obtain lithium oxide powder. The lithium oxide powder is then subjected to multi-stage cyclone separation by an induced draft fan and enters a collection tank. The lithium oxide powder in the collection tank is then sieved through a vibrating screen to obtain micronized lithium oxide.

[0056] The mass of the micronized lithium oxide obtained in this embodiment is 17.289 kg, the purity of the micronized lithium oxide is 99.332%, and the particle size is D10 = 5.731 μm, D50 = 30.390 μm, and D90 = 78.716 μm.

[0057] Example 4

[0058] Add 5 kg of 99.99% pure lithium metal to a titanium crucible and evacuate to a vacuum of 5 × 10⁻⁶. -3 Pa was heated at 400°C for 60 min to obtain fully molten metallic lithium.

[0059] Adjust the nozzle angle of the spray disc to 60°, introduce oxygen with a purity of 99.99% at a pressure of 4MPa, open the guide valve, lift the metal plug rod at the bottom of the titanium crucible, and let the liquid lithium metal flow into the spray disc through the 250°C guide nozzle. It is broken and atomized by oxygen spraying. The broken liquid lithium metal reacts with oxygen to produce lithium oxide droplets.

[0060] Lithium oxide droplets are passed into a cooling chamber containing cosmetic-grade white oil as the cooling medium and cooled to 20°C to obtain lithium oxide powder. The lithium oxide powder is then subjected to multi-stage cyclone separation by an induced draft fan and enters a collection tank. The lithium oxide powder in the collection tank is then sieved through a vibrating screen to obtain micronized lithium oxide.

[0061] The mass of the micronized lithium oxide obtained in this embodiment is 10.804 kg, the purity of the micronized lithium oxide is 99.351%, and the particle size is D10 = 4.168 μm, D50 = 27.022 μm, and D90 = 69.069 μm.

[0062] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing micronized lithium oxide, characterized in that, Includes the following steps: 1) After heating and melting lithium metal, it is oxidized by blowing oxygen to obtain lithium oxide droplets; 2) After cooling the lithium oxide droplets, they were sequentially separated and sieved to obtain micronized lithium oxide powder; The separation is a multi-stage cyclone separation; The heating and melting are carried out under vacuum conditions, where the vacuum level is ≤1×10⁻⁶. -1 Pa; The pressure of the gas being sprayed is ≥4MPa; The D90 of the micronized lithium oxide is 60~80μm.

2. The method for preparing micronized lithium oxide according to claim 1, characterized in that, The purity of the lithium metal is ≥99.9%.

3. The method for preparing micronized lithium oxide according to claim 1, characterized in that, The heating and melting temperature is 390~410℃, and the heating and melting time is 50~70min.

4. The method for preparing micronized lithium oxide according to claim 2 or 3, characterized in that, The purity of the oxygen is ≥99.99%.

5. The method for preparing micronized lithium oxide according to claim 4, characterized in that, The cooling temperature is ≤25℃, and the cooling medium is white oil.

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