阅读说明：本技术 一种锂渣资源化回收处理方法 (Lithium slag recycling treatment method ) 是由 李红毅 常捷 温常凯 孙手棒 蒋汉九 陈健 徐建军 金洪亮 陈果 常乐 黄贝 于 2020-12-09 设计创作，主要内容包括：本发明公开了一种锂渣资源化回收处理方法,包括以下步骤：将锂渣与锂辉石混合,并进行酸化调浆后焙烧得到含有Li_2SO_4的酸化焙烧料；向酸化焙烧料中加入石灰石进行中和,然后对酸化焙烧料进行水浸并进行过滤,得到浸出渣与浸出液；向浸出液中加入碳酸盐得到Li_2CO_3；将得到的Li_2CO_3与石灰混合后进行苛化反应得到苛化渣与苛化液；将苛化渣回用与酸化焙烧料混合,对苛化液进行浓缩结晶、分离烘干得到LiOH；本发明具有在制备碳酸锂与氢氧化锂的同时,将部分碳酸锂作为原料参与氢氧化锂的制备,同时将氢氧化锂制备过程中产生的苛化渣回用参与碳酸锂的制备,进而实现碳酸锂制备与氢氧化锂制备的联合循环,大大提高了资源回用率。(The invention discloses a lithium slag resource recycling method, which comprises the following steps: mixing the lithium slag and spodumene, acidifying, size mixing and roasting to obtain the Li-containing material 2 SO 4 Acidifying the calcine; adding limestone into the acidified roasting material for neutralization, and then leaching the acidified roasting material with water and filtering to obtain leaching residue and leaching solution; adding carbonate to the leachate to obtain Li 2 CO 3 (ii) a The obtained Li 2 CO 3 Mixing the lime with the causticized slag and the causticized liquid, and then carrying out causticization reaction; recycling the causticized slag, mixing the causticized slag with the acidified roasting material, concentrating, crystallizing, separating and drying the causticized liquid to obtain LiOH; the method has the advantages that when lithium carbonate and lithium hydroxide are prepared, part of lithium carbonate is used as a raw material to participate in the preparation of the lithium hydroxide, and simultaneously causticized slag generated in the preparation process of the lithium hydroxide is recycled to participate in the preparation of the lithium carbonate, so that the combined cycle of the preparation of the lithium carbonate and the preparation of the lithium hydroxide is realized, and the resource recycling rate is greatly improved.)

1. A recycling treatment method for lithium slag is characterized in that the lithium slag is slag obtained by extracting lithium from spodumene through a lithium leaching process by a sulfuric acid method, and the recycling treatment method comprises the following steps:

step 1, mixing the lithium slag and spodumene, acidifying, size mixing and roasting to obtain the Li-containing material₂SO₄Acidifying the calcine;

step 2, adding limestone into the acidified roasting material obtained in the step 1 for neutralization, and then carrying out water leaching on the acidified roasting material and filtering to obtain leaching slag and leaching liquid;

step 3, adding carbonate into the leaching solution to obtain Li₂CO₃；

Step 4, Li obtained in step 3₂CO₃Mixing the lime with the causticized slag and the causticized liquid, and then carrying out causticization reaction;

and 5, recycling the causticized slag in the step 2, mixing the causticized slag with the acidified roasting material and limestone, concentrating, crystallizing, separating and drying the causticized liquid to obtain LiOH.

2. The method for recycling lithium slag as claimed in claim 1, wherein the causticized slag is first stirred and mixed with the acidified roasting material, and then limestone is added.

3. The method for recycling lithium slag as resources according to claim 2, wherein before the causticized slag is mixed with the acidified roasting material, the causticized slag is evaporated and dehydrated in advance.

4. The method for recycling and treating lithium slag as claimed in any one of claims 1 to 3, wherein in the step 1, excessive H is added into the mixture of the lithium slag and spodumene₂SO₄Stirring until the sulfate mineral in the mixture of the lithium slag and the spodumene forms a dispersed suspension state, and roasting at the temperature of 250-300 ℃ to obtain the acidified roasted material.

5. The method for recycling lithium slag as claimed in claim 4, wherein an excessive amount of H is added to the mixture of lithium slag and spodumene₂SO₄Before that, the lithium slag is first crystallized and roasted at 950-1200 deg.c.

6. The lithium slag recycling method according to claim 5, wherein the H is₂SO₄The mass ratio to spodumene is 1.5: 1-2.5:1, the reaction temperature is 45-70 ℃, and the reaction time is 1.5-2 h; said H₂SO₄The mass percentage concentration of (A) is more than or equal to 50%.

7. The method for recycling lithium slag as resources according to any one of claims 1 to 3, wherein the carbonate is added in the step 3 and then stands for 0.5h to 1h to obtain Li₂CO₃Precipitating and supernatant, and then extracting the supernatant for secondary filtration.

8. The method for recycling the lithium slag as a resource according to claim 7, wherein the carbonate is any one of sodium carbonate, potassium carbonate and ammonium carbonate.

9. The method for recycling lithium slag as claimed in any one of claims 1 to 3, wherein Li in the step 4 is recycled₂CO₃Before mixing with lime, use H₂O pre-treatment of Li₂CO₃And (5) carrying out spray washing.

Technical Field

The invention belongs to the technical field of lithium slag recycling treatment, and particularly relates to a lithium slag recycling treatment method.

Background

Lithium products in China are mainly produced and prepared through spodumene, a large amount of lithium slag is generated in the preparation process, the existing treatment method of the lithium slag generally adopts stacking storage, not only occupies land, but also causes environmental pollution, and other usable substances contained in the lithium slag are wasted. In addition, lithium carbonate is generally prepared by a technique of spodumene based on a sulfuric acid method and lithium hydroxide is prepared by a causticization reaction technique of lithium carbonate and lime, but the existing preparation methods of lithium carbonate and lithium hydroxide are relatively independent, so that waste of substances generated in respective preparation processes is caused.

Disclosure of Invention

The invention aims to provide a lithium slag recycling treatment method, which realizes the recycling treatment and recycling of lithium slag, combines the process for preparing lithium carbonate and lithium hydroxide, realizes the cycle of the process for preparing lithium carbonate and lithium hydroxide and effectively recycles resource products generated in the production process.

The invention is realized by the following technical scheme:

a recycling treatment method for lithium slag, wherein the lithium slag is slag obtained by extracting lithium from spodumene through a lithium leaching process by a sulfuric acid method, and comprises the following steps:

step 1, mixing the lithium slag and spodumene, acidifying, size mixing and roasting to obtain the Li-containing material₂SO₄Acidifying the calcine;

step 2, adding limestone into the acidified roasting material obtained in the step 1 for neutralization, and then carrying out water leaching on the acidified roasting material and filtering to obtain leaching slag and leaching liquid;

step 3, adding carbonate into the leaching solution to obtain Li₂CO₃；

Step 4, Li obtained in step 3₂CO₃Mixing the lime with the causticized slag and the causticized liquid, and then carrying out causticization reaction;

and 5, recycling the causticized slag in the step 2, mixing the causticized slag with the acidified roasting material and limestone, concentrating, crystallizing, separating and drying the causticized liquid to obtain LiOH.

In the step 1, the lithium slag after the lithium is extracted by the sulfuric acid leaching is mixed with spodumene, the sulfuric acid participating in the lithium slag and the sulfate and the spodumene are mixed and roasted, so that the use amount of the sulfuric acid is reduced, lithium can be enriched again by adding the lithium slag, the recycling is realized, and the use amount of the lithium slag is smaller than that of the spodumene, and the lithium slag is only auxiliary for recycling. And secondly, the addition of the lithium slag reduces the sintering ring of spodumene roasting, and the high-melting-point lithium slag can reduce the sintering ring of spodumene in a rotary kiln. The dosage of the lithium slag is 12 wt% -38 wt% of the weight of the spodumene.

By preparing Li₂CO₃Part of Li obtained in the process₂CO₃Used as raw material for preparing LiOH, realizes Li₂CO₃Combined preparation with LiOH, and simultaneously recycling causticized slag rich in calcium carbonate obtained in the process of preparing LiOH to prepare Li₂CO₃The process is mixed with the acidized roasting material for preneutralization, so that the dosage of limestone in the subsequent neutralization process is reduced, and meanwhile, Li is realized₂CO₃And (4) a related cycle with the LiOH preparation process.

While preparing Li₂CO₃The leaching residue generated in the process can be used for preparing building concreteAnd finally, resource recycling is realized; the resulting sulphate-containing leachate also produces sulphate as a by-product.

In order to better realize the invention, the causticized slag and the acidized roasting material are stirred and mixed firstly, and then limestone is added, namely, substances such as calcium carbonate and the like contained in the causticized slag and excessive sulfuric acid in the acidized roasting material are pre-neutralized firstly, and then the limestone is added for subsequent neutralization, so that the causticized slag is recycled, and the using amount of the limestone is effectively reduced.

In order to better realize the method, before the causticized slag and the acidized roasting material are mixed, the causticized slag is evaporated and dehydrated in advance, so that the viscosity of the causticized slag is reduced, and the causticized slag can be fully mixed with the acidized roasting material when being recycled.

In order to better implement the invention, further, in the step 1, excessive H is added into the mixture of the lithium slag and the spodumene₂SO₄Stirring until the sulfate mineral in the mixture of the lithium slag and the spodumene forms a dispersed suspension state, and roasting at the temperature of 250-300 ℃ to obtain the acidified roasted material.

To better practice the invention, further, an excess of H is added to the mixture of Li slag and spodumene₂SO₄Before that, the lithium slag is first crystallized and roasted at 950-1200 deg.c.

In order to better implement the invention, further, the H₂SO₄The mass ratio to spodumene is 1.5: 1-2.5:1, the reaction temperature is 45-70 ℃, and the reaction time is 1.5-2 h; said H₂SO₄The mass percentage concentration of the active carbon is more than or equal to 50 percent

In order to better realize the invention, further, the carbonate is added in the step 3 and then stands for 0.5h to 1h to obtain Li₂CO₃Precipitating and supernatant, and then extracting the supernatant for secondary filtration.

In order to better implement the invention, further, the carbonate is any one of sodium carbonate, potassium carbonate and ammonium carbonate.

In order to better implement the present invention,further, Li in the step 4₂CO₃Before mixing with lime, use H₂O pre-treatment of Li₂CO₃Spraying and washing to promote Li₂CO₃For subsequent full causticisation with lime, while Li is washed by spraying₂CO₃Removing the impurities attached to the surface.

Compared with the prior art, the invention has the following advantages and beneficial effects:

(1) according to the invention, sulfuric acid is added into a mixture of lithium slag and spodumene to acidify the lithium slag, then the mixture is roasted to obtain an acidified roasting material, limestone is added into the acidified roasting material to obtain leaching slag and leaching liquid, carbonate is added into the leaching liquid to prepare lithium carbonate, and meanwhile, the obtained leaching slag can be used for preparing building concrete, so that the resource recycling of reaction products is realized while the lithium carbonate is prepared;

(2) mixing part of lithium carbonate obtained in the preparation process of lithium carbonate with lime, obtaining causticized slag and causticized liquid through causticization reaction, recycling the causticized slag rich in limestone to the preparation process of lithium carbonate, crystallizing and drying the causticized slag to obtain a lithium hydroxide product, and realizing resource recycling of the causticized slag while preparing the lithium hydroxide;

(3) according to the invention, part of lithium carbonate in the lithium carbonate preparation process is used as a raw material to participate in the preparation of the lithium hydroxide, and meanwhile, causticized slag rich in limestone generated in the lithium hydroxide preparation process is recycled to participate in the preparation of the lithium carbonate, so that the combined cycle of lithium carbonate preparation and lithium hydroxide preparation is realized, and the resource waste is effectively avoided;

(4) according to the invention, the lithium slag obtained after lithium is extracted by sulfuric acid leaching is mixed with spodumene, sulfuric acid is used in the lithium slag, and sulfate and spodumene are mixed and roasted, so that the use amount of sulfuric acid is reduced, lithium can be enriched again by adding the lithium slag, the recycling is realized, and the use amount of the lithium slag is smaller than that of the spodumene, and the lithium slag is only auxiliary for recycling. And secondly, the addition of the lithium slag reduces the sintering ring of spodumene roasting, and the high-melting-point lithium slag can reduce the sintering ring of spodumene in a rotary kiln.

Drawings

FIG. 1 is a flow chart of the process steps of the present invention;

FIG. 2 is a schematic diagram of the method of the present invention.

Detailed Description

Example 1:

in the method for recycling and processing lithium slag of this embodiment, the lithium slag is slag obtained by extracting lithium from spodumene through a lithium leaching process by a sulfuric acid method, as shown in fig. 1 and 2, and the method includes the following steps:

step 1, mixing the lithium slag and spodumene, acidifying, size mixing and roasting to obtain the Li-containing material₂SO₄The main reaction of the acidified roasting material is as follows:

step 2, adding limestone to the acidified calcine obtained in step 1 for neutralisation, in effect by reaction of limestone with the remaining H2SO4 in the mixed calcine to remove excess H2SO 4. And (3) leaching the mixed roasted material with water, filtering, and filtering to remove CaSO4 generated in the reaction to obtain leaching residues and a leaching solution. The leaching slag mainly contains CaSO4 and a small amount of substances such as CaO, TiO2, Fe2O3 and the like, and can be used for preparing building concrete; the leachate mainly contains Li₂sO₄。

Step 3, adding carbonate into the leaching solution to obtain Li₂CO₃Formation of Li from carbonate ion and lithium ion₂CO₃Precipitating to realize the precipitation of Li₂CO₃And the corresponding sulfate salt, the reaction taking place as follows:

CO₃ ^2-+2Li⁺＝Li₂CO₃↓；

step 4, mixing the Li2CO3 obtained in the step 3 with lime to perform a causticization reaction to obtain causticized slag and causticized liquid, wherein the reaction is as follows:

Ca(OH)₂+Li₂CO₃＝CaCO₃↓+LiOH+H₂O；

CaCO in causticized slag₃The content of the causticizing liquid is more than 95 percent, and the causticizing liquid mainly contains the causticizing liquid.

And 5, recycling the causticized slag in the step 2, mixing the causticized slag with the acidified roasting material and limestone, concentrating, crystallizing, separating and drying the causticized liquid to obtain LiOH.

Because of CaCO in causticized slag₃The content of the acid roasting material is more than 95 percent, so that the causticized slag can be recycled to the step 2 to be mixed with the acid roasting material, and further the material can be recycled; and meanwhile, evaporating and crystallizing the causticized liquid, filtering to realize solid-liquid separation to obtain LiOH crystals, and drying the LiOH crystals to realize the preparation of LiOH.

The process realizes the simultaneous preparation of Li₂CO₃With LiOH, with simultaneous addition of Li₂CO₃Part of Li generated during the preparation₂CO₃Used as raw material for producing LiOH, and is also rich in CaCO generated in the process of preparing LiOH₃The causticized slag and the acidified roasting material are mixed to prepare Li₂CO₃Finally realize Li₂CO₃Associated cycles with the two product preparation processes of LiOH. While in Li₂CO₃CaSO enriched during the preparation process₄The leached slag can be used for preparing building concrete and realizing resource recovery.

Example 2:

in this embodiment, the causticized slag and the acidified roasting material are first stirred and mixed for 0.5h or more, and then the powdered limestone is added and stirred after the causticized slag and the acidified roasting material are uniformly mixed.

Calcium carbonate in the causticized slag firstly reacts with excessive sulfuric acid in the acidified roasting material to carry out preneutralization, and then limestone is added to carry out subsequent neutralization, so that the use amount of the limestone is effectively reduced, the causticized slag is recycled, and the resource waste is avoided.

Other parts of this embodiment are the same as embodiment 1, and thus are not described again.

Example 3:

this example is further optimized on the basis of example 1 or 2 above, wherein in step 1, an excess of H is added to the mixture of Li slag and spodumene₂SO₄Stirring the mixture until the sulfate mineral in the mixture of the lithium slag and the spodumene forms a dispersed suspension state, and roasting the mixture at the temperature of between 250 and 300 ℃ to obtain an acidified roasted material, wherein the reaction is as follows:

the mass ratio of the H2SO4 to the spodumene is 1.5: 1-2.5:1, the reaction temperature is 45-70 ℃, and the reaction time is 1.5-2H; the mass percentage concentration of the H2SO4 is more than or equal to 50%.

The rest of this embodiment is the same as embodiment 1 or 2, and therefore, the description thereof is omitted.

Example 4:

this example was further optimized on the basis of any of the above examples 1 to 3 by adding an excess of H to the mixture of Li slag and spodumene₂SO₄Before that, the mixture of the lithium slag and the spodumene is firstly subjected to crystal transformation roasting at the temperature of 950-1200 ℃.

In general, spodumene mainly contains alpha-spodumene with a compact structure, and is difficult to be added with H subsequently₂SO₄Fully reacts, so alpha-spodumene needs to be subjected to crystal transformation roasting in advance, so that alpha-spodumene is transformed into beta-spodumene with a loose structure, so that H is facilitated₂SO₄The reaction was carried out sufficiently. The reaction is as follows:

the other parts of this embodiment are the same as those of embodiments 1 to 3, and thus are not described again.

Example 5:

this example was further optimized on the basis of any of the above examples 1-4, wherein carbon was added in step 3Standing for 0.5h to 1h after acid salt to obtain Li₂CO₃Precipitating and supernatant, and then extracting the supernatant for secondary filtration.

The carbonate is any one of sodium carbonate, potassium carbonate and ammonium carbonate.

The other parts of this embodiment are the same as those of embodiments 1 to 4, and therefore, the description thereof is omitted.

Example 6:

this embodiment is further optimized based on any one of the above embodiments 1-5, wherein Li in step 4₂CO₃Before mixing with lime, use H₂O pre-treatment of Li₂CO₃Spray washing was carried out with the aim of increasing Li₂CO₃In order to perform a sufficient causticizing reaction with lime added subsequently, and another purpose is to introduce Li₂CO₃And the impurities attached to the lime are removed, so that the subsequent causticization reaction effect with the lime is ensured.

Other parts of this embodiment are the same as any of embodiments 1 to 5, and thus are not described again.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.