阅读说明：本技术 一种从中和除杂锂渣中回收锂的工艺 (Process for recovering lithium from neutralization impurity-removed lithium slag ) 是由 朱强辉 钟亮 李薛勇 袁松 邱艳 袁璐 于 2021-09-10 设计创作，主要内容包括：本发明公开了一种从中和除杂锂渣中回收锂的工艺,涉及锂回收领域,本发明包括如下步骤,步骤一,将中和除杂的锂渣加入循环水打浆,缓慢加入无机酸性物质,并持续缓慢搅拌,调节溶液的PH值；步骤二,通过板框压滤机进行固液分离,压榨得到返溶石膏和含锂母液,将含锂母液返回至调浆工序,加入碳酸钙中和,本发明通过对锂辉石中和除杂的锂渣加硫酸返溶,控制PH的值,将锂渣中吸附的锂溶解在溶液,溶液返回至调浆加碳酸钙工序中,返溶石膏容易过滤,且夹带锂损失较小,该工艺可实现对除杂锂渣的锂回收率大于90％,提高锂辉石提锂的收率,降低生产成本。(The invention discloses a process for recovering lithium from neutralization impurity-removed lithium slag, which relates to the field of lithium recovery and comprises the following steps of firstly, adding the neutralization impurity-removed lithium slag into circulating water for pulping, slowly adding inorganic acidic substances, continuously and slowly stirring, and adjusting the pH value of a solution; and secondly, performing solid-liquid separation through a plate-and-frame filter press, squeezing to obtain re-dissolving gypsum and lithium-containing mother liquor, returning the lithium-containing mother liquor to the size mixing process, and adding calcium carbonate for neutralization.)

1. A process for recovering lithium from neutralization impurity-removed lithium slag is characterized by comprising the following steps: comprises the following steps of (a) carrying out,

adding the lithium slag subjected to neutralization and impurity removal into circulating water for pulping, slowly adding an inorganic acidic substance, continuously and slowly stirring, and adjusting the pH value of the solution;

performing solid-liquid separation through a plate-and-frame filter press, squeezing to obtain re-dissolved gypsum and lithium-containing mother liquor, returning the lithium-containing mother liquor to the size mixing process, and adding calcium carbonate for neutralization;

adding water into the re-dissolved gypsum, pulping, stirring and washing, dissolving lithium adsorbed in the lithium slag in a solution to obtain gypsum with very low lithium content and stirring and washing mother liquor, filtering by adopting filter cloth, and returning the stirring and washing mother liquor to the lithium slag pulp preparation process;

step four, after the mother liquor is repeatedly stirred and washed for multiple times and returned to the lithium slag slurry preparation process, working personnel concentrate and crystallize the stirred and washed mother liquor, dry the gypsum waste residue obtained by filtering at the temperature of 80-150 ℃, crush the lithium slag after drying, and then mechanically activate the lithium slag at the temperature of 250-350 ℃ to obtain the treated lithium slag;

and step five, mixing the lithium slag and the additive, uniformly mixing, grinding in a ball mill, sieving by a 300-mesh sieve, returning to the ball mill for ball milling after sieving, and sieving to pass and detecting the qualified fineness to obtain the fly ash.

2. The process for recovering lithium from neutralization impurity-removed lithium slag according to claim 1, which is characterized by comprising the following steps: the ratio of the lithium slag to the water in the first step is 1: 3-4, and adjusting the pH value of the solution to be 2.

3. The process for recovering lithium from neutralization impurity-removed lithium slag according to claim 1, which is characterized by comprising the following steps: in the first step, the inorganic acidic substance is sulfuric acid, and the concentration of the sulfuric acid is 98%.

4. The process for recovering lithium from neutralization impurity-removed lithium slag according to claim 1, which is characterized by comprising the following steps: and in the second step, the filtering pressure of the plate-frame filter press is controlled to be 0.4-0.6 Mpa.

5. The process for recovering lithium from neutralization impurity-removed lithium slag according to claim 1, which is characterized by comprising the following steps: in the third step, the filtering holes of the filtering cloth are 400-600 meshes.

6. The process for recovering lithium from neutralization impurity-removed lithium slag according to claim 1, which is characterized by comprising the following steps: and in the fifth step, the additive is one or more of kaolin, bentonite and sepiolite.

Technical Field

The invention relates to the technical field of lithium recovery from lithium slag, in particular to a process for recovering lithium from neutralization impurity-removed lithium slag.

Background

Spodumene is one of the main lithium-containing minerals, also called type 2 spodumene, monoclinic system, the crystal is usually columnar, granular or plate-shaped, the color is grey white, grey green, emerald green, purple or yellow, etc., the glass is glossy, and the streak is colorless. The hardness is 6.5-7, the density is 3.03-3.22 g/cm3, spodumene is mainly produced in the mullite, symbiotic minerals comprise quartz, albite, microcline feldspar and the like, the color of the crystal can be changed when the crystal is heated or irradiated by ultraviolet rays, and the crystal can lose luster under the action of sunlight.

At present, the neutralization and impurity removal slag of the spodumene lithium extraction process mainly comprises two treatment processes: 1. the water is added for size mixing, and the calcium carbonate is used in the size mixing process, the process method can recover about 50 percent of lithium in lithium slag, and the leaching and filtering are difficult; 2. calcining the neutralized impurity-removed lithium slag to obtain metal oxides such as lithium, aluminum, iron and the like, and leaching with dilute acid to obtain lithium sulfate mother liquor, wherein the recovery rate of the process can reach 75%, but the process has high energy consumption, the calcination is not easy to operate, and 3, the poor treatment of the lithium slag easily causes environmental pollution.

Disclosure of Invention

The invention aims to: in order to solve the technical problem, a process for recovering lithium from neutralization impurity-removed lithium slag is provided.

In order to achieve the purpose, the invention provides the following technical scheme: a process for recovering lithium from neutralization impurity-removed lithium slag comprises the following steps,

adding the lithium slag subjected to neutralization and impurity removal into circulating water for pulping, slowly adding an inorganic acidic substance, continuously and slowly stirring, and adjusting the pH value of the solution;

performing solid-liquid separation through a plate-and-frame filter press, squeezing to obtain re-dissolved gypsum and lithium-containing mother liquor, returning the lithium-containing mother liquor to the size mixing process, and adding calcium carbonate for neutralization;

adding water into the re-dissolved gypsum, pulping, stirring and washing, dissolving lithium adsorbed in the lithium slag in a solution to obtain gypsum with very low lithium content and stirring and washing mother liquor, filtering by adopting filter cloth, and returning the stirring and washing mother liquor to the lithium slag pulp preparation process;

step four, after the mother liquor is repeatedly stirred and washed for multiple times and returned to the lithium slag slurry preparation process, working personnel concentrate and crystallize the stirred and washed mother liquor, dry the gypsum waste residue obtained by filtering at the temperature of 80-150 ℃, crush the lithium slag after drying, and then mechanically activate the lithium slag at the temperature of 250-350 ℃ to obtain the treated lithium slag;

and step five, mixing the lithium slag and the additive, uniformly mixing, grinding in a ball mill, sieving by a 300-mesh sieve, returning to the ball mill for ball milling after sieving, and sieving to pass and detecting the qualified fineness to obtain the fly ash.

Further, the ratio of the lithium slag to the water in the first step is 1: 3-4, and adjusting the pH value of the solution to be 2.

Further, in the step one, the inorganic acidic substance is sulfuric acid, and the concentration of the sulfuric acid is 98%.

Furthermore, the filtering pressure of the plate-frame filter press in the second step is controlled to be 0.4-0.6 Mpa.

Further, the filter holes of the filter cloth in the third step are 400-600 meshes.

Further, in the fifth step, the additive is one or more of kaolin, bentonite and sepiolite.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, sulfuric acid is added into the spodumene neutralized and impurity-removed lithium slag for re-dissolution, the PH value is controlled, lithium adsorbed in the lithium slag is dissolved in the solution, the solution is returned to the slurry mixing and calcium carbonate adding process, re-dissolved gypsum is easy to filter, the loss of entrained lithium is small, the process can realize that the recovery rate of lithium in the impurity-removed lithium slag is more than 90%, the yield of extracting lithium from spodumene is improved, and the production cost is reduced.

2. According to the invention, an additive is added into the treated lithium slag, wherein the additive is one or more of kaolin, bentonite and sepiolite, after the lithium slag recovery process is completed, gypsum slag obtained by filtering is dried at 80-150 ℃, the lithium slag is crushed after drying, then the lithium slag is subjected to mechanical activation treatment at 250-350 ℃ to obtain the treated lithium slag, the lithium slag and the additive are mixed, the mixture is uniformly mixed and put into a ball mill for grinding, then the mixture is sieved by a 300-mesh sieve, the mixture is returned to the ball mill for ball milling after the sieving is completed, the sieved powder coal ash is qualified after passing and the fineness is detected, the fly ash is prepared, the resource utilization of the gypsum slag can be realized, the waste is changed into the valuable, and the economic benefit is improved.

Detailed Description

The technical solution of the present invention will be further specifically described below by way of examples.

The first embodiment is as follows:

a process for recovering lithium from neutralization impurity-removed lithium slag comprises the following steps,

adding the lithium slag subjected to neutralization and impurity removal into circulating water for pulping, slowly adding an inorganic acidic substance, continuously and slowly stirring, and adjusting the pH value of the solution;

performing solid-liquid separation through a plate-and-frame filter press, squeezing to obtain re-dissolved gypsum and lithium-containing mother liquor, returning the lithium-containing mother liquor to the size mixing process, and adding calcium carbonate for neutralization;

adding water into the re-dissolved gypsum, pulping, stirring and washing, dissolving lithium adsorbed in the lithium slag in a solution to obtain gypsum with very low lithium content and stirring and washing mother liquor, filtering by adopting filter cloth, and returning the stirring and washing mother liquor to the lithium slag pulp preparation process;

step four, after the mother liquor is repeatedly stirred and washed for multiple times and returned to the lithium slag slurry preparation process, working personnel concentrate and crystallize the stirred and washed mother liquor, dry gypsum waste residues obtained by filtering at 80 ℃, crush the lithium slag after drying, and then mechanically activate the lithium slag at 250 ℃ to obtain treated lithium slag;

step five, mixing the lithium slag and the additive, uniformly mixing, grinding in a ball mill, sieving by a 300-mesh sieve, returning to the ball mill for ball milling after sieving, and detecting the qualified fineness to obtain the fly ash

As a further aspect of the present invention, in the first step, the ratio of the lithium slag to the water is 1: and 3, adjusting the pH value of the solution to be 2.

As a further aspect of the present invention, in the first step, sulfuric acid is selected as the inorganic acidic substance, and the concentration of sulfuric acid is 98%.

As a further aspect of the present invention, in step two, the filtration pressure of the plate and frame filter press is controlled to 0.4 MPa.

As a further aspect of the present invention, in step three, the filtration pores of the filter cloth are 400 mesh.

As a further aspect of the present invention, in the fifth step, the additive is one or more of kaolin, bentonite and sepiolite.

Example two:

a process for recovering lithium from neutralization impurity-removed lithium slag comprises the following steps,

adding the lithium slag subjected to neutralization and impurity removal into circulating water for pulping, slowly adding an inorganic acidic substance, continuously and slowly stirring, and adjusting the pH value of the solution;

performing solid-liquid separation through a plate-and-frame filter press, squeezing to obtain re-dissolved gypsum and lithium-containing mother liquor, returning the lithium-containing mother liquor to the size mixing process, and adding calcium carbonate for neutralization;

adding water into the re-dissolved gypsum, pulping, stirring and washing, dissolving lithium adsorbed in the lithium slag in a solution to obtain gypsum with very low lithium content and stirring and washing mother liquor, filtering by adopting filter cloth, and returning the stirring and washing mother liquor to the lithium slag pulp preparation process;

step four, after the mother liquor is repeatedly stirred and washed for multiple times and returned to the lithium slag slurry preparation process, working personnel concentrate and crystallize the stirred and washed mother liquor, dry gypsum waste residues obtained by filtering at 120 ℃, crush the lithium slag after drying, and then mechanically activate the lithium slag at 300 ℃ to obtain treated lithium slag;

step five, mixing the lithium slag and the additive, uniformly mixing, grinding in a ball mill, sieving by a 300-mesh sieve, returning to the ball mill for ball milling after sieving, and detecting the qualified fineness to obtain the fly ash

As a further aspect of the present invention, in the first step, the ratio of the lithium slag to the water is 1: and 3, adjusting the pH value of the solution to be 2.

As a further aspect of the present invention, in the first step, sulfuric acid is selected as the inorganic acidic substance, and the concentration of sulfuric acid is 98%.

As a further aspect of the present invention, in the second step, the filtration pressure of the plate and frame filter press is controlled to 0.5 MPa.

As a further development of the invention, the filter holes of the filter cloth in step three are 500 meshes.

As a further aspect of the present invention, in the fifth step, the additive is one or more of kaolin, bentonite and sepiolite.

Example three:

a process for recovering lithium from neutralization impurity-removed lithium slag comprises the following steps,

adding the lithium slag subjected to neutralization and impurity removal into circulating water for pulping, slowly adding an inorganic acidic substance, continuously and slowly stirring, and adjusting the pH value of the solution;

performing solid-liquid separation through a plate-and-frame filter press, squeezing to obtain re-dissolved gypsum and lithium-containing mother liquor, returning the lithium-containing mother liquor to the size mixing process, and adding calcium carbonate for neutralization;

adding water into the re-dissolved gypsum, pulping, stirring and washing, dissolving lithium adsorbed in the lithium slag in a solution to obtain gypsum with very low lithium content and stirring and washing mother liquor, filtering by adopting filter cloth, and returning the stirring and washing mother liquor to the lithium slag pulp preparation process;

step four, after the mother liquor is repeatedly stirred and washed for multiple times and returned to the lithium slag slurry preparation process, working personnel concentrate and crystallize the stirred and washed mother liquor, dry gypsum waste residues obtained by filtering at 150 ℃, crush the lithium slag after drying, and then mechanically activate the lithium slag at 350 ℃ to obtain treated lithium slag;

step five, mixing the lithium slag and the additive, uniformly mixing, grinding in a ball mill, sieving by a 300-mesh sieve, returning to the ball mill for ball milling after sieving, and detecting the qualified fineness to obtain the fly ash

As a further aspect of the present invention, in the first step, the ratio of the lithium slag to the water is 1: and 4, adjusting the pH value of the solution to be 2.

As a further aspect of the present invention, in the first step, sulfuric acid is selected as the inorganic acidic substance, and the concentration of sulfuric acid is 98%.

As a further aspect of the present invention, in step two, the filtration pressure of the plate and frame filter press is controlled to 0.6 MPa.

As a further development of the invention, the filter holes of the filter cloth in step three are 600 meshes.

As a further aspect of the present invention, in the fifth step, the additive is one or more of kaolin, bentonite and sepiolite.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.