Preparation method of battery grade lithium carbonate

Abstract

The invention provides a preparation method of battery grade lithium carbonate. The preparation method is characterized by preparing slurry from industrial lithium carbonate, pumping the slurry into a first-order reaction kettle, introducing collected CO2, carrying out full reaction, then carrying out filtration to obtain filter residues, preparing slurry from the filter residues, pumping the slurry into a second-order reaction kettle, introducing collected CO2, carrying out full reaction, then carrying out filtration to obtain filter residues, preparing slurry from the filter residues, pumping the slurry into a third-order reaction kettle, introducing high-purity CO2, carrying out full reaction and then carrying out filtration; firstly pumping the filtrate obtained after each-order filtration into a decomposition reaction kettle, then transferring the filtrate to a causticization reaction kettle, adding a Ca(OH)2 solution, carrying out immediate filtration and washing to obtain filtrates, pumping the filtrates into a concentration kettle, pumping the concentrate into a synthesis kettle after the concentrate passes through a column filled with ion exchange resin and introducing high-purity CO2, thus preparing high-purity battery grade lithium carbonate. The preparation method has the beneficial effects that by utilizing the advantage that lithium carbonate can undergo hydrogenation and efficiently utilize high-purity CO2, CO2 is recycled in the reaction process and foreign ions in the kettles can be ensured to be removed, thus reducing the production cost.

Description

technical field [0001] The invention belongs to the technical field of battery-grade lithium carbonate, and in particular relates to a preparation method of battery-grade lithium carbonate. Background technique [0002] As an important compound of lithium salt, lithium carbonate has many industrial uses. According to GB / T 11075-2013, YS / T582-2013 and other relevant national and industry standards, industrial grade Li 2 CO 3 Content less than 99.5%, battery grade Li 2 CO 3 The content is 99.5% to 99.9%. [0003] Lithium carbonate is widely used in glass ceramics, new energy vehicles, alloys, and medicine. In recent years, with my country's policy of advocating low-carbon and environmental protection, the new energy industry has developed rapidly. The most notable is the rapid growth of the lithium battery industry. Lithium cobalt oxide, lithium nickel oxide, lithium nickel cobalt oxide, lithium iron phosphate and nickel cobalt manganese acid Lithium and other positive ele...

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Problems solved by technology

[0005] For example, the hydrogenation process is used in Chinese patent 200710019052.3 "A Process for Producing High-purity Lithium Carbonate Using Salt Lake Lithium Resources". The salt lake brine is used as raw material to prepare industrial-grade lithium carbonate, and CO 2 Gas hydrogenation, after the relevant impurity removal process, decomposes lithium bicarbonate under negative pressure conditions, and washes multiple times to prepare battery-grade lithium carbonate; there are also related journal documents "The influence of hydrogenation conditions on the purification of lithium carbonate" (Materials Guide B, 2011.7, 25, Wu Jian) ​​pointed out that 10g of lithium carbonate and carbon dioxide flow rate is 1L / min, react at 25 ℃ for 40min, the carbon dioxide utilization rate obtained is only 7.6%; "Coarse lithium carbonate purification process research" (inorganic salt Industry, 2013.8, 8, Li Yanru) chooses 10g of lithium carbonate to react with 1L / min carbon dioxide at 20°C for 150min, and the utilization rate of carbon dioxide is 2.02%. The amount is very small, which affects the mass transfer process, and then affects the CO 2 Gas utilization, resulting in waste of gas raw materials

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