KR102325755B1 - Method of manufacturing lithium compound - Google Patents

Abstract

A lithium compound manufacturing method according to an embodiment of the present invention comprises the steps of preparing a product by roasting a lithium-containing ore with an acid; mixing the product with alkaline leachate to prepare a leachate; and purifying the leachate.

Description

Lithium compound manufacturing method {METHOD OF MANUFACTURING LITHIUM COMPOUND}

The present invention relates to a method for preparing a lithium compound. More specifically, it relates to a method for stably and rapidly preparing a lithium purification solution from a lithium-containing material.

Recently, the demand for lithium ion batteries is increasing due to the growth of various electronic devices such as mobile devices and electric vehicle markets. Lithium is one of the main materials for batteries, and its use is gradually increasing, raising the possibility of depletion. Lithium can be extracted from ores containing lithium, for example, spodumene concentrate through solid phase reaction treatment and then water leaching. At this time, since many other impurity ions exist in the lithium leaching aqueous solution, they are removed and then commercialized. In general, in the method of removing impurities, an alkaline auxiliary material is added later to the lithium leaching solution, and the reaction is performed in the form of a precipitate to separate. However, the above method has disadvantages in that it is difficult to control the process depending on the auxiliary material or the process treatment is delayed due to the low reactivity, so a more efficient method is required.

The present invention provides a method for preparing a lithium compound. More specifically, it provides a method for stably and rapidly preparing a lithium purification solution from a lithium-containing material.

A lithium compound manufacturing method according to an embodiment of the present invention comprises the steps of preparing a product by roasting a lithium-containing ore with an acid; mixing the product with alkaline leachate to prepare a leachate; and purifying the leachate.

In the step of preparing the leachate by mixing the product with alkaline leachate, the pH of the prepared leachate may be maintained constant.

In the step of mixing the product with alkaline leachate to prepare a leachate, the initial pH of the alkaline leachate may be between 9 and 13.

In the step of preparing the leachate by mixing the product with alkaline leachate, the pH of the prepared leachate may be 6 to 9.

In the step of mixing the product with alkaline leachate to prepare a leachate, the alkaline leachate may be an aqueous alkali solution.

In the step of mixing the product with alkaline leachate to prepare a leachate, the concentration of the alkali substance in the aqueous alkali solution may be 2.1 to 3.8% by weight.

In the step of mixing the product with alkaline leachate to prepare a leachate, the molar concentration of hydroxide ions in the aqueous alkali solution may be greater than 0.5 M and less than 1.0 M.

The alkali material may be a hydroxide or carbonate of an alkali metal of Group 1 or Group 2 on the periodic table.

The step of preparing the leachate by mixing the product with alkaline leachate removes impurities, including Al, Fe, Si, Mg, Ca, Mn, or a combination thereof, present in the product to reduce the concentration of impurities in the prepared leachate. It may be a step to control.

The lithium compound manufacturing method according to an embodiment of the present invention has the effect of stably and rapidly performing the purification process of the lithium leaching solution.

The lithium compound manufacturing method according to an embodiment of the present invention can maximize the reactivity of impurity ions by using an aqueous solution in which an alkaline auxiliary material is dissolved in advance instead of water when water leaching of lithium-containing ore, which makes the process stable and allows you to operate quickly.

1 is a graph of pH change according to reaction time in Comparative Example 1 and Example 1 of the present invention.
2 is a graph of pH change according to reaction time in Comparative Example 2 and Example 2 of the present invention.
3 is a graph of pH change according to reaction time in Examples 3 to 8;

In this specification, terms such as first, second and third are used to describe, but are not limited to, various parts, components, regions, layers and/or sections. These terms are used only to distinguish one part, component, region, layer or section from another part, component, region, layer or section. Accordingly, a first part, component, region, layer or section described below may be referred to as a second part, component, region, layer or section without departing from the scope of the present invention.

In the present specification, when a part "includes" a certain component, this means that other components may be further included rather than excluding other components unless otherwise stated.

In this specification, the terminology used is for the purpose of referring to specific embodiments only, and is not intended to limit the present invention. As used herein, the singular forms also include the plural forms unless the phrases clearly indicate the opposite. The meaning of "comprising," as used herein, specifies a particular characteristic, region, integer, step, operation, element and/or component, and includes the presence or absence of another characteristic, region, integer, step, operation, element and/or component. It does not exclude additions.

In the present specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It means to include one or more selected from the group consisting of.

In this specification, when a part is referred to as being “on” or “on” another part, it may be directly on or on the other part, or the other part may be accompanied in between. In contrast, when a part refers to being "directly above" another part, the other part is not interposed therebetween.

Although not defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Commonly used terms defined in the dictionary are additionally interpreted as having a meaning consistent with the related technical literature and the presently disclosed content, and unless defined, they are not interpreted in an ideal or very formal meaning.

In addition, unless otherwise specified, % means weight %, and 1 ppm is 0.0001 weight %.

In an embodiment of the present invention, the meaning of further including the additional element means that the remaining iron (Fe) is included by replacing the additional amount of the additional element.

Hereinafter, embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein.

Impurity ions in the lithium leaching solution are mainly removed in the form of precipitates by adding an alkaline reagent, for example, sodium hydroxide, calcium hydroxide, etc. to adjust the pH of the solution from acidic to neutral to weakly basic. However, the pH becomes acidic again due to the ion exchange reaction on the surface of the precipitate generated at this time, and the dissolution reaction of crude or low-solubility reagents such as calcium hydroxide is slow, and the time to reach neutral pH is prolonged, thereby slowing the processing speed. Therefore, when water leaching of lithium-containing ore, the reactivity of impurity ions can be maximized by using an aqueous solution in which an alkaline auxiliary material is dissolved in advance instead of water, which makes it possible to operate the process stably and quickly. The present invention shows how to use such alkaline leachate when leaching lithium containing ores.

A lithium compound manufacturing method according to an embodiment of the present invention comprises the steps of preparing a product by roasting a lithium-containing ore with an acid; mixing the product with alkaline leachate to prepare a leachate; and purifying the leachate.

Each step is described below.

First, the lithium-containing ore is roasted with acid to produce a product.

In this step, the acid may be a strong acid, more specifically sulfuric acid. It may also include a step of heat-treating the lithium-containing ore prior to this step. That is, in this step, the heat-treated ore may be roasted with acid. In the step of heat-treating the lithium-containing ore, the lithium-containing ore may be heat-treated at a heat treatment temperature of 1000 to 1250 °C. When spodumene ore is used as a lithium-containing ore, α-spodumene ore can be converted into β-spodumene ore through heat treatment. The spodumene ore may contain 2.5 to 3.5 weight percent lithium.

Next, the product is mixed with alkaline leachate to prepare a leachate.

In this case, the alkaline leachate may be used instead of water in the prior art. In the prior art, after water leaching with neutral leachate, a process of removing impurities by increasing the pH of the leachate to remove impurities was performed. However, in one embodiment of the present invention, the lithium-containing ore is leached with alkaline leachate, and impurities are purified in this step.

Therefore, in this step, mixing the product with alkaline leachate to prepare a leachate is to remove impurities, including Al, Fe, Si, Mg, Ca, Mn, or a combination thereof, present in the product, and It may be a step of controlling the concentration of impurities.

The alkaline leachate may be an aqueous alkaline solution. More specifically, it may be a hydroxide or carbonate of an alkali metal of Group 1 or Group 2 on the periodic table. More specifically, it may be an aqueous sodium hydroxide solution, an aqueous calcium hydroxide solution, an aqueous calcium carbonate solution, or a combination thereof. The initial pH of the alkaline leachate at this stage may be 9 to 13. More specifically, it may be 11 to 13.

The pH of the leachate prepared by this step may be kept constant. If the pH is kept constant, impurities can be removed quickly and stably.

The pH of the leachate prepared by this step may be 6 to 9. More specifically, it may be 6 to 8 days.

In addition, the concentration of the alkali substance in the aqueous alkali solution in this step may be 2.1 to 3.8 wt%. More specifically, it may be 2.2 to 2.9 wt%. If leachate with too little or too much alkalinity is used, the alkaline strength of the leachate may need to be moderate because aluminum or silicon with amphoteric properties is not completely removed. In general, the amount of the alkaline aqueous solution used for leaching depends on the acidity of the lithium raw material, and the usage standard can be determined by the molar concentration of hydroxide ions in the aqueous solution. At this time, the appropriate range of the hydroxide ion molar concentration may be more than 0.5M and less than 1.0 M.

Hereinafter, the present invention will be described in more detail through examples. However, these examples are only for illustrating the present invention, and the present invention is not limited thereto.

Example

Experimental Example 1 - Comparison when using sodium hydroxide solution for purification

Comparative Example 1 (N0)

After mixing lithium roasted light with water, a 25% sodium hydroxide solution was added to monitor the pH. The pH was adjusted to 7 or more, but it was decreased soon, so that the sodium hydroxide solution was added again so as to have a pH of 7. However, this phenomenon occurs continuously and repeatedly. This shows the difficulty of process control.

Example 1 (N1)

Lithium roasting light was directly mixed with 2.5% sodium hydroxide solution, and the pH value was kept constant at 7. The pH of a 2.5% sodium hydroxide solution is 12. This shows that the purification process can proceed stably.

1 shows a graph of pH change according to reaction time in Comparative Example 1 (N0) and Example 1 (N1).

Experimental Example 2 - Comparison of using calcium hydroxide powder for purification

Comparative Example 2 (C0)

After mixing lithium roasted light with water, 95% calcium hydroxide powder was added to monitor the pH. It can be seen that when 5 hours have elapsed, the pH value is in the range of 5.5 to 10.0, which is an indicator of the completion of purification. This increases the processing time and negatively affects productivity.

Example 2 (C1)

As soon as lithium roasted light is mixed directly with 2.3% calcium hydroxide solution, the pH value is within the range of completion of purification and is continuously maintained. The pH of a 2.3% calcium hydroxide solution is 12.5. This shows that the purification process is fast and stable.

2 shows a graph of pH change according to reaction time in Comparative Example 2 (C0) and Example 2 (C1).

Experimental Example 3 - Comparison of impurity ion concentration change according to sodium hydroxide aqueous solution concentration during purification

When a certain amount of lithium roasted light was mixed and reacted with aqueous solutions having different sodium hydroxide concentrations (Examples 3 to 8), the pH was monitored over time. 3 shows a graph of the pH change according to the reaction time in Examples 3 to 8.

After the reaction for 2 hours, the mixed solutions were filtered to obtain a clear solution, and component analysis was performed thereon. Table 1 shows the ion concentration after 2 hours of reaction according to the sodium hydroxide concentration. As can be seen in Table 1, it can be seen that the impurities are not removed as aluminum and silicon are detected at 2% or less or 4% or more. Therefore, it was confirmed that the appropriate sodium hydroxide concentration was about 2.1 to 3.8%.

division NaOH concentration Li Al Fe Si Na Example 3 2.0% 8.4 0.18 0.02 0.01 11.1 Example 4 2.3% 8.7 <0.003 <0.003 <0.003 13.0 Example 5 2.5% 8.5 <0.003 <0.003 <0.003 14.1 Example 6 2.8% 8.4 <0.003 <0.003 <0.003 15.5 Example 7 3.0% 8.2 0.004 <0.003 <0.003 16.5 Example 8 4.0% 8.3 0.21 <0.003 0.06 21.4

The present invention is not limited to the embodiments, but may be manufactured in various different forms, and those of ordinary skill in the art to which the present invention pertains may develop other specific forms without changing the technical spirit or essential features of the present invention. It will be appreciated that this may be practiced. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (9)

roasting the lithium-containing ore with acid to produce a product;
mixing the product with alkaline leachate to prepare a leachate; and
purifying the leachate;
including,
mixing the product with alkaline leachate to prepare a leachate,
The alkaline leachate is an aqueous alkali solution,
The concentration of the alkali material in the aqueous alkali solution is 2.1 to 3.8% by weight of the lithium compound manufacturing method.
According to claim 1,
mixing the product with alkaline leachate to prepare a leachate,
A method for preparing a lithium compound wherein the pH of the prepared leachate is maintained constant.
According to claim 1,
mixing the product with alkaline leachate to prepare a leachate,
The method for producing a lithium compound, wherein the initial pH of the alkaline leachate is 9 to 13.
3. The method of claim 2,
mixing the product with alkaline leachate to prepare a leachate,
The method for preparing a lithium compound, wherein the prepared leachate has a pH of 6 to 9.
delete delete According to claim 1,
mixing the product with alkaline leachate to prepare a leachate,
The molar concentration of hydroxide ions in the aqueous alkali solution is more than 0.5 M and less than 1.0 M lithium compound manufacturing method.
According to claim 1,
The method for producing a lithium compound wherein the alkali material is a hydroxide or carbonate of an alkali metal of Group 1 or 2 on the periodic table.
According to claim 1,
The step of mixing the product with alkaline leachate to prepare a leachate comprises:
and controlling the concentration of impurities in the prepared leachate by removing impurities including Al, Fe, Si, Mg, Ca, Mn, or a combination thereof present in the product.

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