RU2531019C1 - Mix material for extraction of lithium from lithium concentrates mix - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy. The mix material for lithium extraction contains a mix of spodumene (SK) and lepidolite (LK) lithium concentrates and sodium carbonate. And the mix material contains sodium carbonate on the basis of obtaining of the mass ratio SiO₂/(Na₂O+K₂O+Li₂O), equal to 2.2÷2.3, and spodumene and lepidolite concentrates contains with the mass ratio SK/LK, equal to (1.0÷1.3):1.0, and mass ratio of oxides SiO₂/(Na₂O+K₂O+Li₂O), equal to 4.7÷4.8.

EFFECT: increase of level of lithium extraction is provided.

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Description

The invention relates to metallurgy, in particular to the processing of spodumene and lepidolite concentrates.

Spodumene (LiAl [Si ₂ O ₆ ]) and lepidolite (KLi _1,5 Al _1,5 [Si ₃ AlO ₁₀ ] [F, OH] ₂ are some of the main industrial lithium minerals [1, pp. 12-18, 20 ]. In mining and processing plants, spodumene and lepidolite are extracted from ores into the corresponding concentrates. Due to the low lithium content in lithium concentrates (not more than ~ 4 wt.% [1, p. 92]), known methods for extracting lithium from them are technically difficult to implement and very expensive.

To extract lithium from its minerals, a large number of known methods can be used: sulfuric acid, calcareous and others [1, pp. 121-154; 2, pp. 226-272]. The main part of these methods for the extraction of lithium from lithium concentrates is designed to process only individual lithium minerals, which significantly narrows the raw material base of lithium industries. The number of known charge compositions in the joint processing of lithium concentrates is currently limited.

Known charge for the extraction of lithium from a mixture of SC and LK [2, p.243-249], adopted for the analogue used in the process: 1) mixing SC with limestone (in a mass ratio of 1: 3) and adding to the resulting mixture of LK in the amount 10 ÷ 40 wt.%; 2) activating preparation of a mixture composed of concentrates and limestone by sintering it at a temperature of 900 ÷ 950 ° C followed by grinding of cake; 3) water leaching of the activated mixture (ground cake).

As follows from the specified composition of the initial raw material mixture, the mass ratio of SC and LC in it is 1: (0.4 ÷ 1.6).

As a result of sintering of a mixture of concentrates with an alkaline earth flux — limestone — alkaline decomposition of SC and LA occurs and the formation of water-insoluble sodium aluminate and calcium silicate. Due to the excess of limestone supplied to the stage of sintering with concentrates, during the leaching of the crushed cake, water-soluble lithium hydroxide and water-insoluble calcium aluminate are formed:

Li ₂ O · Al ₂ O ₃ + Ca (OH) ₂ = 2LiOH + CaO · Al ₂ O ₃ ↓

After separation of the pulp from the stage of leaching the ground cake to a solution of lithium hydroxide and Al-, Ca-, silicon-containing cake, water washing the cake from an alkaline solution, the cake is dumped into a dump. The use of an analog charge with significant volumes of limestone at the stage of its blending with concentrates (115 ÷ 214% of the total mass of concentrates) leads to an extremely poor raw material charge (~ 1 wt.% Lithium and less), which leads to high costs for the extraction of lithium from this charge, the formation of a large mass of dump cake (washing of which from lithium hydroxide is a difficult task), as a result of which significant amounts of lithium are lost with the cake, so that the extraction of lithium from a mixture of concentrates in solution is it is only 80–84 mass%.

The disadvantage of using an analog charge in the processing of a mixture of SC and LC is the low extraction of lithium from a mixture of these concentrates in solution.

The closest in combination of features to the present invention is the use of a mixture for the extraction of lithium from a mixture of SC and LK [3], taken as a prototype and consisting of a mixture of SC and LK based on the calculation of the mass ratio SlO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in a mixture of 4.5, the mass ratio of SC and LC in their mixture is 1.0: 1.8, with the addition of flux (soda ash) based on the calculation of the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in the prepared mixture, equal to 2.5. The specified mixture is subjected to activating preparation by melting it at a temperature of 1350 ° C, granulating the melt with water, grinding granulated melt. Sulfatization of the crushed melt with 93% sulfuric acid and aqueous leaching of sulfated melt ensures the conversion of lithium to water-soluble lithium sulfate. The advantage of using the charge-prototype in comparison with the charge-analogue is the high extraction of lithium from activated raw materials in the target solution of lithium sulfate, amounting to 99%.

However, the disadvantage of using the charge of the prototype is that it limits the raw material base of lithium hydrometallurgy by the mass ratio of SC and LC in their mixture of 1.0: 1.8. In practice, there is a need to carry out joint processing of SC and LK with a different ratio of them in the mixture, and, in particular, equal to (1.0 ÷ 1.3): 1.0.

The objective of the invention is to develop the composition of the charge from SC and LK, expanding the raw material base of lithium hydrometallurgy and providing a high degree of lithium extraction during processing of SC and LK with a new (1.0 ÷ 1.3: 1.0) ratio of them in the raw mix of concentrates .

The technical result consists in increasing the degree of extraction of lithium to industrially acceptable (99.0 ÷ 99.2%) by mixing spodumene and lepidolite concentrates based on the calculation of the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in a mixture of 4.7 ÷ 4.8.

The solution of this problem and the achievement of relevant technical results is ensured by the fact that in the process of lithium extraction from a mixture of lithium concentrates, a charge consisting of spodumene, lepidolite concentrates and sodium carbonate is used, and the mixture contains sodium carbonate based on the calculation of the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O), equal to 2.2 ÷ 2.3, and spodumene and lepidolite concentrates contains a mass ratio of SC / LC equal to (1.0 ÷ 1.3): 1.0, and the mass ratio oxides SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O), equal to 4.7 ÷ 4.8.

Composing a mixture of these concentrates provides the required amount of fluxing components during the melting of the mixture and water granulation of the melt, due to their presence in the concentrates: blending of concentrates in such a mass ratio (when the mass ratio in the mixture of silicon and alkali metals present in the concentrates in terms of their oxides is 4.7 ÷ 4.8) provides a significant transfer of lithium into acid-soluble compounds. The addition of sodium carbonate to the mixture of SC and LC of sodium carbonate in an amount determined by the mass ratio in the charge between silicon and alkali metals in terms of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) oxides equal to 2.2 ÷ 2.3 , provides in the process of melting the mixture and water granulation of the melt, in combination with the above features, almost complete conversion of lithium into acid-soluble compounds. Due to this, with subsequent leaching of the granulate with sulfuric acid, a high extraction of lithium in solution is achieved. This ensures the expansion of the raw material base of lithium hydrometallurgy by involving SC and LK in the joint processing with a new ratio in the charge equal to (1.0 ÷ 1.3): 1.0.

An example of the use of the inventive charge

The chemical composition of the used SC and LC is similar to that given in [3].

The use of the mixture is carried out by preparing mixtures of SC and LC, the amount of each of which is determined on the basis of obtaining the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in the mixture equal to 4.7 ÷ 4.8.

Sodium carbonate is added to the resulting mixtures to obtain a mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in a charge of 2.2–2.3. Next, the prepared mixture is melted in a graphite crucible at 1350 ° C for 30 minutes. The melt is granulated in cold water with a temperature of 15 ° C, the obtained melt granulate is crushed. After grinding, the granulate melt is granulated in water at T: W = 1: 0.8. The resulting pulp is treated with 93% sulfuric acid with an acid flow rate of 0.7 ml per 1 g of melt granulate. The resulting sulfates are leached with water at T: W = 1: 3 (from the original granulate) for 40 minutes at a temperature of 95 ° C. The resulting sulfate pulp is filtered, the filtered cake is subjected to 2-fold filter-repulpative washing with water, acidified with sulfuric acid to an acid concentration in water of 10 g / l, at T: W = 1: 6 (according to the initial melt granulate) and a temperature of 90 ° C within 15 minutes The residual lithium content in the cake determines the degree of lithium extraction from the melt-granulate into the solution.

Analysis of the indicators achieved when using the inventive charge, shows that this provides the ability to extract lithium into solution at 99.0 ÷ 99.2% of the mass. (table, examples 2, 3, 6 and 7). The blends presented in examples 2, 3, 6 and 7 contain mixtures of SC with LK with a mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) = 4.7 ÷ 4.8 [after adding soda to these mixtures the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in the resulting mixture is 2.2 ÷ 2.3]. Thus, the implementation of the invention allows to involve in the joint processing of SC with LK with a mass ratio of these concentrates in their mixture (1.0 ÷ 1.3): 1.0. This ratio of SC and LC in their mixture expands the raw material base of lithium hydrometallurgy based on the processing of SC and LC with a new ratio of them in the raw material charge. An increase in the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in the charge of SC, LA, and soda above 2.3 (due to a reduction in soda consumption) leads to a decrease in lithium extraction to 97.0–97.5 % of the mass. (table, examples 4 and 8).

Table Comparative indicators of the process of extraction of lithium from lithium-containing concentrates when using
the claimed charge and charge prototype. No. at
measure Charge Mass ratio
SC / LC in their mixture The content of SiO ₂ , Na ₂ O, K ₂ O, Li ₂ O and
ratio SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O)
in a mixture of SC and LC Additive Na ₂ CO ₃ to a mixture of SC with LC,% wt. Mass
ratio
SiO ₂ / (Na ₂ O + K ₂ O +
Li ₂ O) in the charge Quantity
state
Li dump
Nome
keke, g Extraction of Li in solution (cake),% mass. SiO ₂ ,% wt. Na ₂ O,% wt. K ₂ O,% wt. Li ₂ O,% wt. SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) (mass.) one The inventive charge 1.0 / 1.0 60.9 6.1 5,0 1.8 4.7 27.5 2.1 0.10 99.0 2 1.0 / 1.0 60.9 6.1 5,0 1.8 4.7 25.8 2.2 0.10 99.0 3 1.0 / 1.0 60.9 6.1 5,0 1.8 4.7 23,2 2,3 0.09 99.1 four 1.0 / 1.0 60.9 6.1 5,0 1.8 4.7 21.0 2,4 0.25 97.5 5 1.3 / 1.0 61.2 6.3 4.6 1.8 4.8 27.9 2.1 0.10 99.0 6 1.3 / 1.0 61.2 6.3 4.6 1.8 4.8 26.1 2.2 0.10 99.0 7 1.3 / 1.0 61.2 6.3 4.6 1.8 4.8 23.9 2,3 0.08 99,2 8 1.3 / 1.0 61.2 6.3 4.6 1.8 4.8 21.7 2,4 0.30 97.0 9 Prototype charge 1.0 / 1.8 60,2 5,6 5.9 1.8 4,5 18.0 2,5 0.10 99.0 Note: in examples 1-9, the charge of lithium with a charge (granulate) is 10 g.

The reduction in the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O) in the charge of SC, LA and soda below 2.2 (table, examples 1 and 5) (due to an increase in soda consumption) does not provide an additional increase in the degree extraction of lithium, which is in examples 1 and 5 (table) 99.0% of the mass.

The table for comparison shows the results of the processing of a mixture of SC and LK using a mixture of the prototype (example 9), which allows sufficiently fully recover lithium (99% by mass), but limiting the raw material base of lithium hydrometallurgy by the initial charge from SC and LK with their ratio 1.0 ÷ 1.8.

Thus, the inventive charge provides effective extraction of lithium from a mixture of SC and LA in a solution of 99.0 ÷ 99.2% of the mass. The use of the inventive charge in comparison with the charge-prototype provides the expansion of the raw material base of lithium hydrometallurgy due to the involvement of SC and LK in the joint processing with a new ratio of these concentrates in their mixture. The inventive charge allows the use of machine calculation of the composition of the melted charge.

Information sources

1. Ostroushko Yu.I., Buchihin P.I., Alekseeva V.V. et al. Lithium, its chemistry and technology. M .: Atomizdat, 1960 .-- 200 p.

2. Plyushchev V.E., Stepin B.D. Chemistry and technology of compounds of lithium, rubidium and cesium. M .: Chemistry, 1970 .-- 408 p.

3. Pat. 2299253 RF, IPC S22V 26/12. The method of extraction of lithium from a mixture of lepidolite and spodumene concentrates / V.I. Samoilov, N.I. Shipunov. 2007. Bull. Number 14.

Claims (1)

A charge for lithium extraction containing a mixture of spodumene (SC) and lepidolite (LA) lithium concentrates and sodium carbonate, characterized in that it contains sodium carbonate based on the calculation of the mass ratio of SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O ), equal to 2.2 ÷ 2.3, and the spodumene and lepidolite concentrates contain a mass ratio of SC / LC equal to (1.0 ÷ 1.3): 1.0, and a mass ratio of oxides SiO ₂ / (Na ₂ O + K ₂ O + Li ₂ O), equal to 4.7 ÷ 4.8.