CZ2005587A3 - Separation process of lithium carbonate from used batteries of Li-MNOi2 type - Google Patents

Abstract

The method of separation of lithium carbonate is based on the vacuum transfer of the used Li-MnO.sub.2.n batteries. at 550-650.degree.C, cooling of the reaction products in air, mechanical separation of the dust part, so-called strand from the honeycomb battens, rubbing of the garnet in distilled H.sub.2.nO at room temperature, liquid and solid phase ratio of 20-30 : 1 for 0.5-2 h, filtering off the leachate and crystallizing the lithium carbonate from the extract after evaporation of the corresponding volume of liquid. After separation of the liquid and solid phases, lithium carbonate is obtained, which is desiccated in air at 105.degree.C without washing. The produced lithium carbonate is suitable for the preparation of lithium-containing chemicals, for example for the electrolytic production of lithium or for the preparation of raw materials for glass and ceramic industry or for the production of enamels or for the preparation of additives for the electrolyte for the production of aluminum.

Description

Technical field

The present invention relates to a new technology for producing lithium carbonate from used LiMnO2 batteries.

BACKGROUND OF THE INVENTION

Li-MnO2 batteries are primary cells. They have a limited number of components that irreversibly transform into products when the cell is connected. Their total electrochemical reaction is: 2Li + 2Μηθ2 -> Μη2θ3 + L12O. By introducing electricity from the outside, the products cannot be converted to the original compounds and the primary batteries become waste when they are discharged. The use of Li-MnO2 lithium batteries in the Czech Republic has been increasing rapidly in recent years.

Although Li-MnO2 lithium batteries are a valuable raw material for the recovery of lithium compounds, there is no technology in the Czech Republic for their recycling and recovery for the recovery of lithium or its compounds. In untreated or deactivated form, these batteries accumulate in landfills as hazardous waste. There is no simple suitable technology for their separate recycling in the world. In some countries, Li-MnCh batteries are not sorted and, along with other lithium primary batteries, are recycled using energy-intensive processes.

SUMMARY OF THE INVENTION

The main object of the invention is a method of separating lithium carbonate from used primary lithium batteries of the Li-MnO2 type, which consists in roasting the batteries at 550 - 650 ° C in a vacuum furnace, cooling reaction products in air, mechanically separating the dust part. leaching the roast in distilled H 2 O at room temperature, filtering out the leach and crystallizing lithium carbonate from the leachate after evaporating the corresponding volume of liquid. Under these conditions, more than 95% of L12O or (LiMnCh) and Μη2θ3 or MnCh reactions with the present graphite component of the batteries are converted to L12CO3 and MnO. The resulting bail contains on average 4.8-5.5% Li, 48-52% Mn, about 6% C, up to 0.6% Fe and 0.2-0.3% Si, Ni, K, Na. Praženec a major component of MnO or (FeO) o, O99 (MnO) ₀ 9oi further L12CO3 K.2 and insignificant amount of (NH 4) H (SO 4). Using lower roasting temperatures such as 450 ° C does not completely convert L12O to L12CO3, some of the lithium remains poorly soluble in water as LiMnO2. Using higher roasting temperatures, e.g. 750 ° C, the water solubility of L12CO3 decreases. Untreated or finely ground fret is leached in distilled H2O at room temperature and a liquid to solid phase ratio (k: p) of 2030: 1. Under these conditions, 76-84% Li is transferred to the solution, while virtually all of the Mn and other metals remain in the leach containing an average of 0.6% Li. In the next step, due to the different solubility of L12CO3 and the sulphates or chlorides present, especially alkali metals, with controlled evaporation, L12CO3 will obtain technical purity.

The following examples illustrate but do not limit the scope of the invention.

Examples

Example 1

By leaching unground ground sleeper produced by roasting used LiMnC> 2 primary batteries at 650 ° C in H 2 O at room temperature; k: p = 25: 1; reaction time of 2 h, 77% Li was transferred to the leachate. Separation of the solid and liquid phases by filtration gave a leachate which contained 1.48 g Li / L and a leach containing 1.45% Li, 69.29% Mn as MnO. Evaporation of 95% of the original volume of the extract gave a precipitate after filtration, which was air-dried at 105 ° C without washing.

Produced product - lithium carbonate, contained min. 99.5% Li 2 CO 3; maximum content of detected impurities: 0.02% Al; 0.09% Si; 0.09% Sx; 0.16% Cl; 0.06% K; 0.01% Ca

Example 2

By leaching unground roast produced by roasting used LiMnO 2 primary batteries at 650 ° C in H 2 O at room temperature; k: p = 25: 1; reaction time of 2 h, 77% Li was transferred to the leachate. Separation of the solid and liquid phases by filtration gave a leachate which contained 1.48 g Li / L and a leach containing 1.45% Li, 69.29% Mn as MnO. Evaporation of 90% of the original volume of the extract gave a precipitate after filtration, which was air-dried at 105 ° C without washing.

Produced product - lithium carbonate, contained min. 99.7% L12CO3; maximum content of detected impurities: 0.02% Al; 0.07% Si; 0.05% Sx; 0.06% Cl; 0.03% K; 0.02% Ca

Example 3

Leaching the ground fret formed by roasting used Li-MnO2-type primary batteries at 650 ° C in H2O at room temperature; k: p-20: 1; reaction time of 1 h, 77% Li was transferred to the leachate. Separation of the solid and liquid phases by filtration yielded an extract containing 1.84 g of Li / L and a leach containing 1.26% Li, 58.05% Mn as MnO. Evaporation of 95% of the original volume of the extract gave a precipitate after filtration, which was air-dried at 105 ° C without washing.

Product produced - lithium carbonate, contained min. 99.5% Li ₂ CO 3; maximum content of detected impurities: 0.02% Al; 0.09% Si; 0.09% Sx; 0.16% Cl; 0.06% K; 0.01% Ca

Example 4

Leaching the ground fret formed by roasting used Li-MnO2-type primary batteries at 650 ° C in H2O at room temperature; k: p = 25: 1; reaction time 0.5 h, 84% Li was transferred to the leachate. Separation of the solid and liquid phases by filtration yielded an extract containing 1.54 g of Li / L and a leach containing 0.7% Li, 65.3 l% Mn as MnO. Evaporation of 95% of the original volume of the extract gave a precipitate after filtration, which was air-dried at 105 ° C without washing.

Produced product - lithium carbonate, contained min. 99.5% Li 2 CO 3; maximum content of detected impurities: 0.02% Al; 0.09% Si; 0.09% Sx; 0.16% Cl; 0.06% K; 0.01% Ca

Example 5

By leaching ground roast resulting from roasting at 550 ° C of used Li-MnO 2 primary batteries in H 2 O at room temperature; k: p = 30: 1; reaction time 0.5 h, 79% Li was transferred to the leachate. Separation of the solid and liquid phases by filtration gave a leachate which contained 1.44 g Li / L and a leach containing: 1.36% Li, 59.49% Mn as MnO. Evaporation of 95% of the original volume of the extract gave a precipitate after filtration, which was air-dried at 105 ° C without washing.

Produced product - lithium carbonate, contained min. 99.5% Li 2 CO 3; maximum content of detected impurities: 0.02% Al; 0.09% Si; 0.09% Sx; 0.16% Cl; 0.06% K; 0.01% Ca

Industrial applicability

According to the invention, the product of lithium recycling from used Li-MnO2 batteries is lithium carbonate, the purity of which is suitable for the preparation of lithium-containing chemicals, eg for the electrolytic production of lithium or for the raw materials for the glass and ceramic industry of electrolytes for aluminum production.

The novelty of the invention consists in the thermal treatment of spent batteries and leaching of the resulting bail in distilled water, under precisely defined conditions, to obtain pure lithium carbonate without the need for subsequent refining.

An advantage of the invention is that the above-described process is technologically undemanding and does not require the use of chemicals.

Claims (2)

PATENT CLAIMS: Method for separating lithium carbonate from used Li-MnO 2 batteries, characterized in that by vacuum roasting of used Li-MnO 2 batteries at 550 - 650 ° C, cooling the reaction products in air, mechanically separating the dust part, so-called sleepers, from the battery shells 76-84% Li was dissolved in the distilled H2O at room temperature, 20-30: 1 liquid to solid phase ratio by leaching the roast. Separation of the liquid and solid phases by filtration of the leach and subsequent crystallization of the lithium carbonate from the leachate by evaporation of an appropriate volume of liquid yields lithium carbonate, which is air-dried at 105 ° C without washing. A method for separating lithium carbonate from used Li-MnCL-type batteries according to claim 1, characterized in that it uses lithium to convert leached ground roast solution formed by roasting used Li-MnCL-type primary batteries at 650 ° C in H 2 O at room temperature; k: p = 25: 1 for 0.5 h. Separation of the solid and liquid phases by filtration yields a liquor and a leach. Evaporation of 95% of the original leachate yields a precipitate after filtration, which is air-dried at 105 ° C without washing.