Method for preparing high-purity lithium oxide from lithium carbonate

Abstract

The invention discloses a method for preparing high-purity lithium oxide from lithium carbonate. The method comprises the following steps: A, performing acidification neutralization, namely putting battery-grade lithium carbonate into a reaction container, adding concentrated nitric acid, dropwise adding lithium hydroxide and nitric acid, and controlling the pH value to 6-8; B, performing filtering decontamination, namely filtering a mixed solution, dropwise adding lithium hydroxide and nitric acid till the pH value is 11-13, filtering so as to obtain a secondary filtering solution, and dropwise adding lithium hydroxide and nitric acid into the secondary filtering solution till the pH value is 1-2 so as to obtain an adjusted solution; C, performing crystallization, separation and drying, namely performing evaporation crystallization on the adjusted solution, performing cooling centrifugal separation, and drying so as to obtain lithium nitrate; and D, performing high-temperature decomposition, namely putting the lithium nitrate into a decomposition furnace, vacuuming to minus 0.01MPa to minus 0.09MPa, rapidly heating to 500 DEG C within 2-3 hours, heating to 650-750 DEG C within 6-10 hours, keeping the temperature for 8-12 hours, and keeping a vacuum degree of minus 0.01MPa to minus 0.09MPa in the heating and temperature keeping process, thereby obtaining high-purity lithium oxide finally. The method disclosed by the invention is simple in process, low in cost of raw materials and the like, low in unit energy consumption, relatively thorough in decomposition, high in purity of the prepared lithium oxide, and high in production efficiency.

Description

technical field [0001] The invention relates to a method for preparing lithium oxide, in particular to a method for preparing high-purity lithium oxide by using lithium carbonate. Background technique [0002] With the continuous development of new energy vehicles, lithium batteries are more and more widely used in new energy batteries. Lithium oxide is a non-aqueous electrolyte with excellent performance. In addition to the characteristics of general lithium batteries, batteries made of it also have the characteristics of low cost and environmental friendliness. In addition, lithium oxide is also widely used in glass, ceramics, metallurgy, nuclear reaction and other industrial fields. [0003] At present, there are four main methods for preparing lithium oxide: (1) Lithium oxide is produced by reacting lithium metal with oxygen in a molten state, but due to the high cost and high activity of lithium metal, the reaction is too violent and the reaction is not easy to control...

AI Technical Summary

Problems solved by technology

[0003] At present, there are four main methods for preparing lithium oxide: (1) Lithium oxide is produced by reacting lithium metal with oxygen in a molten state, but due to the high cost and high activity of lithium metal, the reaction is too violent and the reaction is not easy to control. and low production efficiency

(2) Lithium carbonate is decomposed to produce lithium oxide under the condition of reduced pressure of 700°C and high temperature, but this method takes a long time, often more than 50 hours, and the decomposition of carbonic acid is often not very thorough, so the main content of lithium oxide obtained is not high. , the purity is not enough

(3) Anhydrous lithium hydroxide decomposition method, the decomposition temperature of lithium hydroxide is 800°C, and the crystal water is difficult to remove, the unit energy consumption is high, and it is difficult to decompose thoroughly; (4) first use lithium hydroxide and hydrogen peroxide The reaction generates lithium peroxide, and then heats and decomposes lithium peroxide under vacuum conditions to prepare lithium oxide. Lithium peroxide needs to be around 870°C to obtain high-concentration lithium oxide, but the main content is difficult to reach more than 98%, and the process is long. ,higher cost

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