CN102398910A

CN102398910A - Method for removing cationic impurities of calcium, magnesium, iron, sodium and potassium from cell grade lithium carbonate

Info

Publication number: CN102398910A
Application number: CN2010105592820A
Authority: CN
Inventors: 张海军; 苏怡兵; 杨瑛
Original assignee: Lanzhou University
Current assignee: Lanzhou University
Priority date: 2010-11-25
Filing date: 2010-11-25
Publication date: 2012-04-04
Anticipated expiration: 2030-11-25
Also published as: CN102398910B

Abstract

The invention discloses a method for removing cationic impurities of calcium, magnesium, iron, sodium and potassium from cell grade lithium carbonate. The method comprises the following steps: 1, accessing a gas containing more than 99.5% of carbon dioxide to a mixed system of industrial lithium carbonate and redistilled water, and dissolving the carbon dioxide solid; 2, adding a lithium-containing amino acid chelating agent with the molar amount of 1-3 times a molar mount needed by the removal of the total content of the cationic impurities, reacting for several minutes with stirring, heating the obtained solution to decompose LiHCO3 into Li2CO3 which can be precipitated, filtering, and calcinating to obtain the cell grade lithium carbonate. The method has the following advantages: the chelating agent, which contains no impurity ions which contain sodium ions, potassium ions and the like and can cause secondary pollution, can be repeatedly used; contents of various cationic impurities in the prepared cell grade lithium carbonate are lower than standards of the cell grade lithium carbonate; and after the impurity removal, Li2CO3 generated by the decomposition of LiHCO3 cannot be washed or can be directly calcinated after washing once or twice, so the lithium loss caused by repeated product washing is reduced, and the lithium recovery rate in the impurity removal process can reach above 95%.

Description

A kind of method of removing calcium in the battery-level lithium carbonate, magnesium, iron, sodium, potassium cationic impurity

Technical field

The present invention relates to a kind of method of removing foreign ion, specifically refer to a kind of method of removing cation impurities such as calcium in the battery-level lithium carbonate, magnesium, iron, sodium, potassium, the field that is applied to prepare battery-level lithium carbonate.

Background technology

Li ₂CO ₃Being most important lithium salts in the lithium compound, is the main raw material of other high purity lithium compound of preparation and lithium alloy.Thereby Li ₂CO ₃Production be the link of the most basic a, most critical in the lithium industry.The lithium cell industry is fast-developing in recent years, impels the main raw material Li that produces anode material of lithium battery ₂CO ₃Demand significantly increase.

At present, lithium compound all extracts from contain lithium salts lake or lithium ore both at home and abroad.Though because the salt lake is different with composition of ores, the extraction process of lithium has nothing in common with each other, the primary process of preparation Quilonum Retard can be summarized as successively:

Evaporate brine concentrate or ore to decompose back enrichment method Li → removal of impurities (removing impurity such as Fe, Mn, Pb, Ca, Mg, Na, K successively) → be precipitated as thick Quilonum Retard → dissolving deep impurity-removing → secondary sedimentation afterwards transition be Quilonum Retard.

Mainly adopted precipitator method removal of impurities in this process, effect receives the influence of the difficulty soluble salt solubleness that forms bigger.Because partly precipitated has formed the solubility colloid, make it remove effect and can only reach 10 usually simultaneously ²The order of magnitude of ppm.Especially the character of Ca, Mg and Li are quite similar, are difficult to eliminate.Therefore can only obtain industrial lithium carbonate, wherein still have the multiple cation impurities such as Ca, Mg, Fe, Na, K of certain content, can not directly be used for the preparation of lithium battery material.

Common battery-level lithium carbonate preparation method is with industrial lithium carbonate acidifying or logical CO at present ₂Make it form LiHCO ₃Solution utilizes the further deep impurity-removing of various ion exchange resin or all ingredients, makes LiHCO through heating ₃Decompose, recrystallization becomes Li ₂CO ₃After, washing, purifying forms again.The impurity-eliminating effect of these methods is unsatisfactory, and the various chemicals self that especially added also need be removed through washing, makes that the content of foreign ion is difficult to control in the Quilonum Retard in the large-scale industrial production, and quality product can not guarantee.

Summary of the invention

To the problems referred to above, the objective of the invention is to design a kind of method of effectively removing for preparing multiple cation impurity in the battery-level lithium carbonate technology by industrial lithium carbonate.

Technical scheme of the present invention is:

A kind of method of removing cation impurities such as calcium in the battery-level lithium carbonate, magnesium, iron, sodium, potassium, realize through following method:

1, redistilled water and industrial lithium carbonate are mixed in the ratio of mass ratio 33-100:1 after, feed content and be higher than 99.5%CO ₂Gas, hydrogenation forms LiHCO ₃Solution;

2, contain lithium propylhomoserin complexing agent can by polynary amino carboxy chelating agent such as diethylenetriamine pentaacetic acid, YD 30, teiethylene tetramine-hexacetic acid etc. with Lithium Hydroxide MonoHydrate reaction process;

Containing the polynary complexone of lithium can be by the polynary amino carboxy chelating agent of be prone to buying of analytical pure such as diethylenetriamine pentaacetic acid, YD 30, teiethylene tetramine-hexacetic acid etc.; Be dispersed in the water by mass ratio 1:7.5; After being heated to more than 60 ℃, adding mass percentage concentration again and be 10% analytical pure lithium hydroxide aqueous solution its dissolving is got final product fully.

(M * V), wherein W is the polynary amino carboxy chelating agent total mass number that takes by weighing to the volumetric molar concentration C=W/ of polynary propylhomoserin sequestrant in this solution, and M is its molecular weight, and V is with dm ³Overall solution volume for unit.

3, according to the composition analysis result of industrial lithium carbonate, what in this solution, add 1～3 times of molar weight desiring the decationize content of impurities contains the polynary aminocarboxylate chelator of lithium, after stirring reaction 1-10 minute, heats this solution and makes LiHCO to 80-100 ℃ ₃Decompose and generate Li ₂CO ₃And separate out, take advantage of heat to filter with the sintered glass funnel decompression, will filter back gained solid oven dry then, in 400-600 ℃ of calcination 0.5-3 hour, can obtain battery-level lithium carbonate;

4, it is acid the filtrating of above-mentioned filtration gained being regulated pH, and preferably pH makes the soluble chelating agent that has combined foreign ion change the polynary aminocarboxylic acid that is insoluble in water again into less than 3, after filtering, washing, promptly can be recycled.

The invention has the advantages that: do not contain the foreign ion that Na, K etc. can cause secondary pollution in the sequestrant; The Li of preparation ₂CO ₃In various impurity ion content all be lower than the battery-level lithium carbonate standard; After the removal of impurities by LiHCO ₃Decompose the Li that generates ₂CO ₃Can be without washing or 1-2 the direct calcination in back of washing, thus reduced because of cleaning product repeatedly causes the loss of lithium, and the recovery of Li can reach more than 95%; Sequestrant can use repeatedly.

Embodiment

Below the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein only is used for explanation and explains the present invention, and be not used in qualification the present invention.

Embodiment 1

Water and industrial lithium carbonate blending ratio 33:1

The industrial lithium carbonate and the 500ml water that take by weighing 15.1 grams 99% mix, and feed CO under the room temperature ₂To system clarification, in solution, add YD 30 three lithium salt solutions of the 0.34mol/L that 25ml made, stir 30min post-heating to 85 ℃, the Quilonum Retard filtration under diminished pressure of separating out.The gained solid is in 550 ℃ of dry 3h, product foreign matter content analysis in table 1.

Embodiment 2

Water and industrial lithium carbonate blending ratio 100:1

The industrial lithium carbonate and the 500ml water that take by weighing 5 grams 99% mix, and feed CO under the room temperature ₂To clarification, in solution, add YD 30 three lithium salt solutions of the 0.34mol/L that 10ml made, stir 30min post-heating to 85 ℃, the Quilonum Retard filtration under diminished pressure of separating out, the 20ml water washing is once.The gained solid is in 550 ℃ of dry 3h.Product foreign matter content analysis in table 1.

Table 1. product foreign matter content analytical table

Embodiment 3

The preparation of YD 30 three lithium salt solutions

Take by weighing 14.6 gram YD 30s and be scattered in the 110ml water, be heated to 60 ℃ under stirring, add the lithium hydroxide solution of 36ml 10% again, obtain YD 30 three lithium salt solutions of clear.

The volumetric molar concentration of this solution is 14.6g/ (292g/mol * 0.146L)=0.34mol/L.

What should explain at last is: the above is merely the preferred embodiments of the present invention; Be not limited to the present invention; Although the present invention has been carried out detailed explanation with reference to previous embodiment; For a person skilled in the art, it still can be made amendment to the technical scheme that aforementioned each embodiment put down in writing, and perhaps part technical characterictic wherein is equal to replacement.All within spirit of the present invention and principle, any modification of being done, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. method of removing cation impurities such as calcium in the battery-level lithium carbonate, magnesium, iron, sodium, potassium, realize through following steps:

(1), redistilled water and industrial lithium carbonate mixed in the ratio of mass ratio 33～100:1 after, feed content and be higher than 99.5% CO ₂Gas, hydrogenation forms LiHCO ₃Solution;

(2), containing lithium propylhomoserin complexing agent is processed by polynary propylhomoserin sequestrant and Lithium Hydroxide MonoHydrate reaction;

(3), in the solution of above-mentioned steps (1), add to desire 1-3 times of molar weight of decationize content of impurities contain lithium propylhomoserin sequestrant, after stirring reaction 1-10 minute, heat this solution and make LiHCO ₃Decompose and generate Li ₂CO ₃And separate out, filter the back at 400-600 ℃ of calcination 0.5-3 hour, can obtain battery-level lithium carbonate;

(4), filtrate filtered in the above-mentioned steps (3) is regulated pH be acid, makes the soluble chelating agent that has combined foreign ion change the polynary propylhomoserin that is insoluble in water again into, promptly can be recycled through filtration, after washing.

2. a kind of method of removing cation impurities such as calcium in the battery-level lithium carbonate, magnesium, iron, sodium, potassium according to claim 1 is characterized in that: described polycarboxylic acid sequestrant is a kind of in Hydrocerol A, diethylenetriamine pentaacetic acid, YD 30, phthalic acid or the tartrate.

3. a kind of method of removing cation impurities such as calcium in the battery-level lithium carbonate, magnesium, iron, sodium, potassium according to claim 1 is characterized in that said step (4) adjusting filtrating pH is less than 3.