Method of manufacturing lithium chemical product

Abstract

To provide a new technology capable of reducing the costs of lithium recovery from a solid waste.SOLUTION: A lithium chemical product is manufactured from a solid waste generated in manufacturing a boron chemical product from an ore containing boron. In this manufacturing method, sulfuric acid having a concentration of 25-35 mass% is blended with a solid waste at normal temperature to extract lithium in the solid waste as lithium ions into a liquid medium of the solid waste.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing lithium chemicals. [Background technology]

[0002] In recent years, the demand for lithium chemicals has increased significantly due to the large number of lithium-ion batteries installed in electric vehicles, and it has been pointed out that lithium resources may be depleted in the future. Furthermore, the number of countries with lithium reserves and countries that manufacture lithium chemicals is limited, and geopolitical risks regarding lithium supplies are also a concern for developed countries. Therefore, obtaining lithium without relying on these countries has become a challenge for countries around the world, and many researchers are working on this issue.

[0003] Now, boron chemicals such as borax are produced from ores containing boron. At this time, lump or muddy waste (hereinafter referred to as "solid waste") is discharged. The solid waste may contain a small amount of lithium. The lithium content in the solid waste is much less than that in lithium ores, but if the amount of solid waste discharged is large, it can be expected to be a lithium resource. For example, in Turkey, the production of boron chemicals from boron ores is active, and a large amount of solid waste, more than one million tons per year, has been accumulated for many years. Therefore, technology to produce lithium chemicals from solid waste is being considered. Normally, lithium in solid waste exists as a water-insoluble compound, so a widely known technology is to convert the compound into a water-soluble compound and extract it with water.

[0004] For example, a technique is known in which a solid waste containing fluorine and lithium is mixed with an aqueous sulfuric acid solution to extract lithium ions, and then a calcium-containing alkaline agent is added to the extract to precipitate and remove the fluorine and sulfate ions from the extract, thereby obtaining a purified lithium solution (see, for example, Patent Document 1).

[0005] Also known in the art is a technique for obtaining a lithium-containing extract by applying hydrochloric acid, sulfuric acid, nitric acid, other acids, or combinations of these acids to lithium-containing ores (clay) or solid waste (see, for example, Patent Document 2).

[0006] As another example of such a technique, Non-Patent Document 1 discloses a technique in which ore (clay) collected from the Kirca deposit in Turkey is treated with 200 mL of 0.25 M HCL aqueous solution per 1 g of the ore to extract lithium from the ore (see, for example, Non-Patent Document 1).

[0007] Also, as a related technology, a technology is known in which solid waste generated in the manufacture of boron chemical products using ore (clay) extracted from the Kirka deposit in Turkey is roasted at 650 to 800°C, and then sulfuric acid is added to the roasted solid waste in an amount of 0.18 to 0.26 in terms of a sulfuric acid / solid waste weight ratio to extract lithium (for example, see Non-Patent Document 2). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2022 / 085635 [Patent Document 2] Special Publication No. 2021-514030 [Non-patent literature]

[0009] [Non-Patent Document 1] Won-Jong Lee et al., J.Miner.Soc.Korea,29(4),167-177 (2016) [Non-Patent Document 2] Abdullah Obut et al., Physicochem.Probl.Miner.Process.,58(4),149635(2022) Summary of the Invention [Problem to be solved by the invention]

[0010] We also obtained solid waste from boron chemical manufacturing and conducted a follow-up lithium extraction test using the above literature to manufacture lithium chemicals (explained in the Examples and Comparative Examples).

[0011] For example, the invention of the aforementioned Patent Document 1 is an invention that solves the problem that the recovery of lithium is hindered by the generation of water-insoluble lithium fluoride because the waste from used lithium batteries containing a large amount of fluorine is used as the raw material. However, since the solid waste we obtained does not contain any fluorine, we could not imagine applying Patent Document 1.

[0012] In addition, the aforementioned Patent Document 2 discloses an invention for concentrating lithium ions from a lithium ion-containing solution using an ion exchange resin. Paragraph 0308 of Patent Document 2 suggests extracting lithium from waste using an acid, but does not disclose the type of acid and its amount used, or a specific process. Since the lithium content in solid waste is usually low, the lithium extraction efficiency or the acid disposal cost greatly affects the price of lithium chemicals depending on the type and amount of acid used. Therefore, the invention of Patent Document 2 cannot motivate the use of solid waste as a raw material for lithium chemicals and the type and amount of acid used to be specified.

[0013] In addition, in the invention of the aforementioned Non-Patent Document 1, the lithium content in the raw ore is about three times (about 0.18%) that of the solid waste we obtained, so if a large amount of acid is used as described in Non-Patent Document 1, the recovery cost per unit weight of recovered lithium will be high. Therefore, the invention of Non-Patent Document 1 is difficult to refer to from a commercial point of view. In addition, the composition of the raw ore is significantly different from that of the solid waste in this embodiment. Therefore, the invention of Non-Patent Document 1 cannot motivate the use of solid waste as a raw material for lithium chemical products and the type and amount of acid used.

[0014] In addition, in the invention of Non-Patent Document 2, the raw material is roasted, but in the raw material we obtained, the extraction efficiency of lithium was reduced by roasting. Although the reason for this is unclear, since the chemical composition of the raw material in the invention of Non-Patent Document 2 is different from that of the solid waste in this embodiment, it is considered that the effect of roasting on the raw material in the extraction of lithium differs depending on the chemical composition of the raw material.

[0015] Thus, the above-mentioned conventional techniques generally have a problem of cost. That is, when a large amount of acid is used to extract lithium from solid waste with a low lithium content, the cost of the acid and other processing costs per unit weight of recovered lithium become high. This significantly reduces profits and may make the technique unprofitable in some cases. In addition, in the method including a roasting step, the cost of roasting is additionally required. Furthermore, the above-mentioned conventional techniques include techniques that are specialized for the composition of solid waste, and depending on the chemical composition of the solid waste, the desired lithium recovery rate may not be expected.

[0016] The challenge is to provide an extraction technology that reduces the recovery cost of lithium per unit weight when recovering lithium from the solid waste generated during the production of boron chemicals that we have obtained. [Means for solving the problem]

[0017] In order to solve the above problems, a method for producing lithium chemical products according to one embodiment of the present invention is a method for producing lithium chemical products from solid waste generated when producing boron chemical products from ore containing boron, and includes a step of mixing the solid waste with sulfuric acid at room temperature in an amount of 25% by mass or more and 35% by mass or less relative to the solid waste, extracting lithium in the solid waste as lithium ions, and adding a liquid medium (for example, water) thereto to obtain a liquid medium containing lithium.

[0018] In order to solve the above-mentioned problems, a method for producing lithium chemical products according to one embodiment of the present invention is a method for producing lithium chemical products from solid waste generated when producing boron chemical products from ore containing boron, the method comprising the steps of: pulverizing the lumpy solid waste; mixing the pulverized solid waste with water to wet the solid waste with water; mixing sulfuric acid at 25% by mass or more and 35% by mass or less with respect to the solid waste with the solid waste at room temperature to extract lithium in the solid waste as lithium ions, and adding a liquid medium (e.g., water) thereto to obtain a liquid medium containing lithium; and removing solid matter from the liquid medium containing lithium ions. the step of contacting the liquid medium from which the solids have been removed with an adsorbent to adsorb the lithium ions in the liquid medium onto the adsorbent; the step of contacting the adsorbent having the lithium ions adsorbed therein with an acid to elute the lithium ions from the adsorbent; the step of adding an alkali to the resulting eluate to adjust the pH of the eluate to 6 or higher; the step of concentrating the eluate adjusted to a pH of 6 or higher; the step of adding a soluble carbonate compound to the resulting concentrated liquid to precipitate lithium carbonate; the step of separating the precipitated lithium carbonate particles from the concentrated liquid and washing them with a saturated aqueous lithium carbonate solution; and the step of drying the washed lithium carbonate particles, in this order. Effect of the Invention

[0019] According to one aspect of the present invention, it is possible to provide a new technology that can further reduce the recovery cost per unit weight of recovered lithium in the recovery of lithium from solid waste. [Brief description of the drawings]

[0020] [Figure 1] 1 is a flowchart showing the process flow of one embodiment of a method for producing a lithium chemical product according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an X-ray diffraction spectrum of the solid waste used in the examples of the present invention. [Diagram 3] FIG. 2 is a graph showing the relationship between the mass ratio of sulfuric acid added to the pulverized solid waste used in the examples and the amount of lithium extracted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] In this specification, unless otherwise specified, the symbol "to" means a range including both ends of the range. In addition, unless otherwise specified, the unit of concentration means a unit based on mass.

[0022] The method for producing lithium chemical products according to an embodiment of the present invention is a method for producing lithium chemical products from solid waste generated when producing boron chemical products from ores containing boron. As one embodiment of the present invention, a technique for producing lithium chemical products of a purity that can be used in lithium ion battery production from industrial waste (solid) will be described. This technique mainly comprises (1) a technique for extracting lithium contained in the waste into a solution, (2) a technique for precipitating impurity ions other than lithium ions in the solution, (3) a technique for adsorbing and desorbing a solution containing lithium ions using an inorganic ion exchanger with high lithium selectivity, and (4) a technique for obtaining purified lithium carbonate from the lithium ion solution after desorption. The boron chemical product is a composition mainly composed of boron, and examples thereof include boron and compounds containing boron, and more specifically, for example, borax as described above.

[0023] [Lithium Chemicals] Lithium chemicals are compositions that are lithium-based, examples of which include lithium and compounds that contain lithium, more specifically lithium carbonate or lithium hydroxide.

[0024] [Solid waste] Solid waste is a solid or muddy waste product discharged as a residue from the production of boron chemicals from boron-containing minerals, such as probertite, colemanite, meyerhoferite, inyoite, pandermite, and datraite.

[0025] An example of solid waste includes the solid waste generated at a boron chemical manufacturing plant in Kirka, Turkey, as shown in the examples below. Lithium is widely distributed in the solid waste. The lithium content in the solid waste is approximately tens of ppm to thousands of ppm (metal-Li-mg / waste-kg). The lithium content of the solid waste used in the examples is approximately 800 ppm.

[0026] In a boron chemical manufacturing plant, when the boron ore (clay) used as the raw material for the boron chemical is different, or when the operating conditions of the manufacturing line for the boron chemical are different, the composition and chemical reactivity of the solid waste generated are not the same. The solid waste used in this embodiment is preferably solid waste that exhibits suitable reactivity when kneaded with sulfuric acid, which will be described later. The reactivity can be confirmed by a kneading experiment with sulfuric acid. In addition, solid waste having substantially the same composition as the composition of solid waste that exhibits suitable reactivity can also be confirmed as a preferred solid waste in this embodiment. The composition of the solid waste can be confirmed by measurement using X-ray diffraction (XRD) or XPS.

[0027] If the composition of the mixture (and its crystalline state) is the same, the XRD spectrum will be the same, and the peak positions will also be the same. However, if the shape of the crystal is different, the reflection area of ​​the crystal plane will change accordingly, and the peak intensity will change accordingly. Also, once the chemical composition (crystal) is determined, the peak value (2θ) is determined, but due to various reasons such as the X-ray source or receiving slit width not being infinitesimal, the peak value will have an error of ±0.2 degrees.

[0028] Whether or not the solid waste is suitable for this embodiment can be determined by whether or not the XRD spectrum is substantially the same as that of a suitable solid waste. For example, the solid waste used in the examples is an example of a suitable solid waste in this embodiment, and the peaks in the XRD spectrum with the intensity rankings up to 12th place shown in Table 2 and FIG. 2 in the examples can be the criterion for determining a suitable solid waste. If 3 or more peaks, preferably 7 or more peaks, of the 12 peaks in the XRD spectrum match with an error of 2θ±0.2 degrees, the solid waste can be recognized as applicable to this embodiment. In this embodiment, the more matching peaks there are, the more preferable the solid waste is. In terms of lithium recovery efficiency and cost reduction, it is preferable that the solid waste in this embodiment is the solid waste used in the examples described below, which is obtained from Kirca.

[0029] The elemental composition of the solid waste preferably contains calcium in the largest amount among elements with atomic numbers of 12 or more. As will be described in detail later, by kneading with sulfuric acid, calcium in the solid waste is insoluble as calcium sulfate and can be removed from the liquid medium by filtration. Therefore, even if a subsequent process for recovering lithium includes a process in which calcium ions are an inhibitory factor, it is possible to substantially suppress the influence of calcium ions in the process. For example, when a manganese oxide-based adsorbent is used in the adsorption process described later, calcium ions are likely to become interfering ions. However, in this embodiment in which the solid waste is treated with sulfuric acid, calcium ions in the liquid medium are precipitated as calcium carbonate, and most of them can be removed from the liquid medium by solid-liquid separation. Therefore, even if a manganese oxide-based adsorbent is used in the adsorption process, the performance of the adsorbent can be fully exhibited.

[0030] In order to improve the contact between the solid waste and sulfuric acid in the extraction step described below, it is preferable that the solid waste used in the extraction step has a large surface area. Therefore, when the solid waste is in a lump form, it is preferable to use a pulverized product of the solid waste as the solid waste. To generate the pulverized product, a known pulverizing device that can be used for pulverizing inorganic materials can be used.

[0031] [Extraction process] In the method for producing lithium chemical products according to the embodiment of the present invention, sulfuric acid is mixed with solid waste at room temperature, kneaded, and the lithium in the solid waste is extracted into a liquid medium as lithium ions. Hereinafter, this extraction process is referred to as the "extraction process."

[0032] The amount of sulfuric acid added in the extraction step is based on the dried and pulverized material. The "room temperature" may be the temperature of the environment in which the present embodiment is carried out, for example, 0 to 40°C. The "liquid medium" is a liquid in which the lithium ions extracted from the solid waste can exist, for example, a liquid mainly composed of water. Examples of the liquid medium include water, an aqueous solution of a salt, and an aqueous solution of a water-soluble organic compound (such as alcohol).

[0033] If the amount of sulfuric acid added in the extraction step is too small, the lithium recovery efficiency is low, and if it is too high, the effect of the lithium recovery efficiency will plateau, and the cost of sulfuric acid itself and the subsequent processing will increase, which is disadvantageous from the viewpoint of cost. In addition, as will be described in detail in the examples below, in the extraction step, the lithium extraction rate into the liquid medium depends on the amount of sulfuric acid added, and the lithium recovery rate increases significantly when the sulfuric acid / solid waste weight ratio reaches a certain value (critical point) or more. From the viewpoint of sufficiently increasing the lithium recovery efficiency, the amount of sulfuric acid added in the extraction step is preferably 25 mass% or more, more preferably more than 26 mass%, and even more preferably 28 mass% or more. In addition, from the viewpoint of suppressing the increase in the cost related to sulfuric acid, the concentration of sulfuric acid in the liquid medium in the extraction step is preferably 35 mass% or less, more preferably 34 mass% or less, and even more preferably 33 mass% or less.

[0034] Concentrated sulfuric acid can be suitably used as the sulfuric acid in the extraction step. Concentrated sulfuric acid is advantageous over other acids in terms of being inexpensive. The concentration of concentrated sulfuric acid is preferably 85 to 98%, more preferably 90 to 98%, and even more preferably 94 to 98%.

[0035] The use of sulfuric acid in the extraction step also provides the following advantage. That is, when sulfuric acid is added to the solid waste, calcium carbonate in the solid waste foams and neutralizes the sulfuric acid, resulting in precipitation as calcium sulfate. This reaction produces a nearly neutral solution. Therefore, in this embodiment, the concentration of sulfuric acid in the liquid medium can be determined taking into consideration the neutralization caused by the reaction with calcium. As a result, it is possible to suppress a decrease in the pH of the liquid medium obtained in the extraction step, and it is possible to carry out the subsequent adsorption of lithium ions without adjusting the pH of the liquid medium.

[0036] In this embodiment, an acid other than sulfuric acid may be used in the extraction step as long as the effects of the present invention can be obtained. Examples of the other acid include hydrochloric acid and nitric acid. In this embodiment, it is preferable that the acid used in the extraction step is substantially only sulfuric acid from the viewpoint of fully exerting the effects of sulfuric acid described above. For example, when hydrochloric acid is used in the extraction step, the pH of the liquid medium is more likely to be on the acidic side (lower) than when only sulfuric acid is used. Therefore, in the subsequent adsorption of lithium ions, it may be necessary to further adjust the pH of the liquid medium to further increase the pH.

[0037] [Other steps] In the embodiment of the present invention, other steps may be further included in the range where the effects of the present invention can be obtained, other than the extraction step described above. For example, the method for producing a lithium chemical product of the present embodiment may further include a step of wetting the solid waste with water (wetting step) before the extraction step, i.e., before mixing with sulfuric acid. In the wetting step, the solid waste may be immersed in water, or water may be directly added to the solid waste and stirred. Wetting, for example, makes the crushed solid waste exhibit smooth kinetics, and makes it easier for the sulfuric acid and the crushed solid waste to be mixed uniformly. From the viewpoint of increasing the contact with water, it is preferable that the solid waste is sufficiently crushed. It is preferable to further include a wetting step from the viewpoint of increasing the contact between the sulfuric acid and the solid waste in the extraction step.

[0038] The method for producing a lithium chemical product of this embodiment may further include a step of separating the liquid medium and solid matter after the lithium ion extraction (liquid medium separation step). The "solid matter" referred to here is the solid waste after mixing with sulfuric acid in the extraction step, or the insoluble component generated in the extraction step. The insoluble component is, for example, calcium sulfate if the solid waste contains calcium. The liquid medium separation step can be performed by a known solid-liquid separation method. Examples of such methods include filtration, decantation, and centrifugation. It is preferable that the liquid medium separation step is composed of a plurality of means from the viewpoint of improving the quality (purity) of the target lithium chemical product.

[0039] In addition, the method for producing a lithium chemical product of this embodiment may further include a step (lithium ion adsorption step) of contacting the lithium-containing liquid medium after the liquid medium separation step, i.e., after removing solids, with an adsorbent to adsorb the lithium ions in the liquid medium to the adsorbent. The lithium ion adsorption step can be performed using a known adsorbent having an adsorption ability for lithium ions. Examples of the adsorbent include manganese oxide-based ion adsorbents. The manganese oxide-based ion adsorbent may be, for example, a single-phase adsorbent of manganese oxide, which may be a porous crystal-type adsorbent having defects of lithium ion diameter. The contact between the adsorbent and the liquid medium may be performed by flowing the particles of the adsorbent in the liquid medium, or by circulating the liquid medium through a fixed bed of the adsorbent. From the viewpoint of stably and easily performing the adsorption of lithium ions and the subsequent desorption operation, it is preferable to circulate the liquid medium through a fixed bed of the adsorbent to contact the adsorbent and the liquid medium. From this viewpoint, the adsorbent is preferably a manganese oxide-based ion adsorbent formed into pellets, and the lithium ion adsorption step is preferably a step of circulating a liquid medium containing lithium through a tube filled with the adsorbent.

[0040] In particular, in the case where the above-mentioned liquid medium separation step is included, calcium ions, which are interfering ions for adsorption, are removed as solids (calcium sulfate) from the liquid medium to be subjected to the lithium ion adsorption step, so that it is possible to fully exhibit the lithium ion adsorption performance of the manganese oxide-based ion adsorbent. In addition, in the case where the above-mentioned liquid medium separation step is included, sulfuric acid is consumed for immobilizing calcium ions (producing calcium sulfate), so that a decrease in the pH of the liquid medium caused by sulfuric acid can be suppressed. Therefore, it is possible to omit the step of adjusting the pH of the liquid medium after the liquid medium separation step and to carry out the lithium ion adsorption step directly from the liquid medium separation step.

[0041] The method for producing a lithium chemical product of this embodiment may further include a step (lithium ion elution step) of contacting an acid with the adsorbent that has adsorbed lithium ions, exchanging the adsorbed lithium ions with hydrogen ions, and eluting the lithium ions from the adsorbent. The inclusion of the lithium ion elution step is preferable from the viewpoint of recovering lithium ions from the adsorbent by a simple operation. The acid in the lithium ion elution step may be any acid that elutes lithium ions from the adsorbent that has adsorbed lithium ions, and examples of such an acid include hydrochloric acid, sulfuric acid, and nitric acid. The concentration of the acid may be sufficient for the adsorbent to elute lithium ions, and may be about pH 0 (1 mol / L for hydrochloric acid).

[0042] In addition, in the method for producing a lithium chemical product of this embodiment, the obtained acidic eluent is neutralized with an alkaline agent. This is preferable from the viewpoint of preventing corrosion of the device in the subsequent stage. The pH of the neutralized liquid medium is preferably 5 or more, more preferably 6 or more. This is because the next step is a concentration step, and if any acid remains, the acidity will increase due to concentration, so it is necessary to thoroughly remove the acid.

[0043] In the method for producing lithium chemical products according to the present embodiment, when an alkaline agent is added to the obtained acidic eluate, for example, until the pH reaches 10, traces of manganese or iron contained therein precipitate, and removing these precipitates can further increase the purity of lithium. After removing the precipitates, the pH of the solution is adjusted to 6 to 8, and then the solution can proceed to a concentration step.

[0044] The method for producing a lithium chemical product according to the present embodiment may further include a step of concentrating the eluent (concentration step). The concentration step can be carried out using a known device capable of concentrating the eluent. In terms of energy efficiency and running costs, a known evaporative concentrator such as an evaporative concentrator can be suitably used for the concentration step.

[0045] One aspect of this embodiment will be described in more detail below. Fig. 1 is a flow chart showing the flow of steps in one aspect of the method for producing a lithium chemical product according to an embodiment of the present invention.

[0046] First, in step S1, the lump solid waste is crushed. The crushing of the solid waste is carried out using a known crushing device. If the solid waste is in a muddy state, the solid waste does not need to be crushed.

[0047] Next, in step S2, the crushed solid waste is mixed with water to wet the solid waste. For example, about 1 kg of water is added to 1 kg of crushed solid waste, and the mixture is kneaded to form a slurry. In this way, a water slurry of the solid waste is prepared.

[0048] Next, in step S3, sulfuric acid is mixed with the solid waste at room temperature. For example, 0.25 to 0.35 kg of sulfuric acid is gradually added to the dry solid waste while further kneading the water slurry. In this way, lithium in the solid waste is extracted into the liquid medium as lithium ions.

[0049] Next, in step S4, solid matter is removed from the aqueous slurry (a reaction mixture of water, sulfuric acid, and solid waste) after the lithium ions have been extracted. For example, once the foaming of the aqueous slurry to which sulfuric acid has been added in step S3 has subsided, further water (or liquid medium) is added, and the supernatant liquid is collected after the solid matter has precipitated. Alternatively, once the foaming has subsided, the solution is filtered to separate the lithium extract from the solid matter. In this way, the liquid medium is obtained from the aqueous slurry. In step S4, water may be added and then filtered so that the lithium concentration in the lithium extract reaches a concentration suitable for the next lithium ion adsorption step (approximately 200 ppm in this embodiment).

[0050] Here, the pH of the liquid medium is measured, and if the pH is equal to or higher than the minimum pH suitable for using the lithium ion adsorbent (for example, pH 6 or higher for the adsorbent used in the examples), the process proceeds to the next lithium ion adsorption step. If the pH of the liquid medium is lower than the minimum value of the recommended pH range for use of the lithium ion adsorbent, the lithium ions of the lithium ion adsorbent in the next step may dissolve, and the adsorption capacity of the adsorbent may decrease. If the pH of the liquid medium is lower than the pH range suitable for using the lithium ion adsorbent, the conditions of step S3 may be reset so that the amount of sulfuric acid added in step S3 is reduced to increase the pH of the liquid medium, or the pH of the liquid medium may be adjusted by adding an alkaline agent to the liquid medium.

[0051] Next, in step S5, the liquid medium after removing the solid matter is brought into contact with the lithium ion adsorbent. Step S5 is, for example, a process of flowing the liquid medium through an adsorption tube filled with the lithium ion adsorbent. In the adsorption tube, the liquid medium may be flowed from top to bottom or from bottom to top.

[0052] The lithium ion adsorbent may be, for example, a manganese oxide-based adsorbent, such as the lithium adsorbent disclosed in International Publication No. 2011 / 058841. From the viewpoint of preventing the adsorbent from flowing out of the cylinder during liquid flow, a lithium ion adsorbent formed into pellets and filled in a cylinder is preferably used. The above-mentioned manganese oxide-based lithium ion adsorbent is capable of adsorbing and desorbing about 15 to 20 g of lithium ions per kg, for example. In step S5, the lithium ions in the liquid medium are adsorbed by the lithium ion adsorbent. In step S5, the lithium ion adsorbent adsorbs only lithium ions, so that for a while after the liquid medium is supplied to the adsorption tube, a liquid that does not substantially contain lithium is discharged from the adsorption tube. The end point of step S5 may be determined by detecting lithium ions in the liquid discharged from the adsorption tube.

[0053] Next, in step S6, the lithium ion adsorbent that has adsorbed lithium ions is contacted with an acid. For example, the acid is supplied to the adsorption tube and passed through the adsorption tube. As an example, about 1 mol / L (about 4%) hydrochloric acid is passed through the adsorption tube. The supply of the acid to the adsorption tube may be the same as the supply direction of the liquid medium to the adsorption tube in step S5 (for example, from top to bottom), or may be the opposite direction (for example, from bottom to top). The former is preferable from the viewpoint of more simply configuring the piping around the adsorption tube, and the latter is preferable from the viewpoint of increasing the contact between the lithium ion adsorbent and the acid. The lithium ions in the adsorbent are exchanged with the hydrogen ions of the hydrochloric acid, and a solution (eluent) containing lithium chloride and hydrochloric acid is discharged from the adsorption tube. During the discharge, the discharged liquid is stored in a tank. The lithium ion concentration of this lithium-containing eluent is about 1000 to 2000 ppm in the tank.

[0054] Next, in step S7, an alkali is added to the obtained eluate to neutralize the eluate. The eluate is strongly acidic and may corrode the equipment in the subsequent steps. Therefore, it is preferable to add an alkaline agent such as sodium hydroxide or potassium hydroxide to the eluate to appropriately neutralize the eluate. For example, sodium hydroxide is added to the eluate while stirring until the pH of the eluate becomes 6 or more. By sufficiently neutralizing in this way, corrosion of the equipment in the subsequent steps is prevented. If the neutralization is not sufficient, the acidity may increase due to concentration, so the pH is set to 6 or more.

[0055] Next, in step S8, the eluate is concentrated. The concentration may be performed under pressure, normal pressure, or reduced pressure as long as the aqueous liquid medium is distilled off from the eluate. One example of the concentration of the eluate is concentration at normal pressure using a stainless steel evaporator. The concentration is performed until the lithium ion concentration reaches 15,000 ppm or more. The reason for the concentration is to increase the amount of lithium carbonate that precipitates in the next step. A concentrated solution containing a high concentration of lithium ions is obtained by step S8.

[0056] Next, in step S9, a carbonate compound is added to the obtained concentrated solution to precipitate lithium carbonate. The carbonate compound may be any compound that reacts substantially only with lithium ions in the concentrated solution to produce lithium carbonate. Examples of the carbonate compound include sodium carbonate, carbon dioxide (air can be exemplified), and potassium carbonate. As an example, lithium carbonate can be precipitated by adding about 210 g of sodium carbonate to 1 L of the concentrated solution, stirring, and leaving it to stand. In step S9, lithium ions among the metal ions in the concentrated solution are precipitated as lithium carbonate, and other metal ions (such as sodium ions) remain dissolved in the concentrated solution. Lithium carbonate is an example of a lithium chemical product in this embodiment. Therefore, a lithium chemical product having a sufficiently high purity can be obtained by step S9.

[0057] Next, in step S10, the precipitated lithium carbonate particles are separated from the concentrated solution and washed with a saturated lithium carbonate aqueous solution. The separation of the lithium carbonate particles from the concentrated solution can be realized by an appropriate method selected from known solid-liquid separation methods, and can be performed, for example, by filtration.

[0058] The filtered particles are washed with a saturated lithium carbonate aqueous solution that does not contain impurities. By such a washing method, the solution containing impurities between the precipitated lithium carbonate particles flows out, and the impurities attached to the surfaces of the precipitated lithium carbonate particles are dissolved in the saturated lithium carbonate aqueous solution and removed. Since the saturated lithium carbonate aqueous solution is used as the washing solution, the lithium carbonate particles do not dissolve, but other impurities are dissolved in the saturated lithium carbonate aqueous solution or washed away. Therefore, the weight loss due to the purification in step S10 is substantially prevented, and a lithium chemical product with a higher purity is obtained. In this way, the lithium carbonate is purified. The saturated lithium carbonate aqueous solution may be, for example, the supernatant of water to which an excess amount of lithium carbonate is added, and may be commonly used between different batches in the production of lithium chemical products.

[0059] Then, in step S11, the washed lithium carbonate particles are dried. Thus, a high-purity lithium chemical product is obtained from the solid waste. The lithium carbonate may be further converted to lithium hydroxide to obtain the lithium chemical product. Alternatively, the drying step of the particles in step S11 may be omitted and the process may proceed to the chemical conversion step of lithium hydroxide.

[0060] Thus, in this embodiment, lithium chemical products are produced from solid waste generated when producing boron chemical products from ore containing boron. According to the method of this embodiment, lithium can be recovered from solid waste with lower operating costs (OPEX) and lower CO2-LCA (life cycle assessment). For example, the lithium chemical products produced by this embodiment have sufficiently low concentrations of components that are avoided as raw materials for lithium ion batteries, such as manganese, aluminum, and boron, and the purity of lithium carbonate can be 99.7% or more. Since the purity of raw material grade lithium carbonate for lithium ion batteries is 99.5% or more, the lithium carbonate produced by this embodiment can be used as a raw material for lithium ion batteries.

[0061] [Modifications] In the process shown in FIG. 1, other steps may be inserted between each step as long as the relative order of each step is not changed. However, roasting is excluded because it significantly increases the recovery cost. For example, a step of washing the lithium ion adsorbent may be further included before step S6 (elution of lithium ions by contacting the adsorbent with an acid). In this way, the process shown in FIG. 1 may further include a pH adjustment step, a dilution step, a filtration step, a washing step, a measurement step, or a storage step.

[0062] In the process shown in Figure 1, an alkaline agent may be added in the neutralization step performed after the elution step until the liquid has a pH of about 10. This will cause manganese or iron to precipitate, and by removing these, a lithium chemical product with a higher purity can be obtained. After removing these, the liquid is adjusted to a pH of 6 or higher before proceeding to the concentration step.

[0063] In addition, in the embodiment of the present invention, it is also possible to recover lithium from the liquid medium in the extraction process by a method other than the above-mentioned adsorption method. Examples of such other methods include a method of separating lithium ions from the liquid medium using a separation membrane of an ion conductor. In such other methods, steps such as pH adjustment and filtration may also be further included as necessary.

[0064] In the embodiment of the present invention, roasting is not necessary. Therefore, the method for producing lithium chemicals according to the embodiment of the present invention does not need to include a step of roasting solid waste. Not including such a roasting step is advantageous for reducing the cost of heating in roasting, and is also advantageous for reducing CO2-LCA in lithium chemicals and further products using the same.

[0065] [Major effects] As described above, the method for producing lithium chemical products according to this embodiment may include the steps of: (1) extracting lithium ions from solid waste by mixing and kneading 25% to 35% by mass of sulfuric acid with the solid waste without heating or calcining, and (2) obtaining a high-purity lithium-containing aqueous solution from the extracted solution using a manganese oxide-based lithium ion adsorbent. According to this embodiment, lithium chemical products can be produced at lower cost and with lower CO2-LCA from solid waste produced in the production of boron chemical products.

[0066] In addition, in this embodiment, a lithium ion adsorbent having high lithium selectivity is used as a method for extracting only lithium from an aqueous solution containing extracted lithium. The synergistic effect of combining the above-mentioned lithium-containing extract and the lithium ion adsorbent can further reduce the manufacturing cost of lithium chemical products. Examples of the synergistic effect include the fact that the filtrate after extraction can be directly advanced to the lithium ion adsorption step without going through a step such as (liquid medium) pH adjustment, or that most cations other than lithium can be removed from the above-mentioned eluent by the alkalinization step (variation).

[0067] More specifically, in this embodiment, by adding sulfuric acid in the range of 25 to 35 mass % to the solid waste, a small amount of sulfuric acid can be reacted without waste, and lithium can be recovered with a high yield. If the amount of sulfuric acid used within that range is adjusted to a pH suitable for using the lithium ion adsorbent, the neutralization step before the adsorption step may become unnecessary. That is, in this embodiment, it is possible to carry out the lithium ion adsorption step directly (without other steps such as pH adjustment) after the above-mentioned liquid medium separation step. Thus, this embodiment is advantageous from the viewpoint of cost reduction by reducing the number of steps.

[0068] In addition, by using an ion exchange adsorbent selective for lithium in this embodiment, it is possible to prevent the entrainment of multiple unnecessary water-soluble ions, and it is possible to omit multiple precipitation separation steps, thereby significantly reducing the cost of chemicals.

[0069] In addition, in this embodiment, there is no need to roast the solid waste at a high temperature. Also, there is no need to heat the solid waste when reacting with sulfuric acid. Therefore, the cost of heating is unnecessary, and the total carbon dioxide emission (LCA) of the manufacturing process can be reduced compared to the method requiring such heating.

[0070] Furthermore, in this embodiment, when the solid waste contains calcium, the residue after the lithium ions are extracted is mainly gypsum, which can be disposed of at low cost or can be recycled to earn a profit on sale.

[0071] Thus, according to this embodiment, the operating costs (costs of chemicals, energy, waste liquid treatment, etc.) spent on lithium per unit weight extracted from solid waste can be very small, and a high-purity battery-grade product can be obtained. Therefore, if lithium products such as lithium ion batteries or lithium all-solid-state batteries are manufactured using the lithium chemical product according to this embodiment as a raw material, it is possible to reduce carbon dioxide emissions during the manufacture of the product. In other words, the lithium chemical product manufactured by the lithium chemical product manufacturing method of this embodiment, or the lithium ion battery or all-solid-state battery manufactured using the lithium chemical product as a material, or the electric power vehicle equipped with the battery, can have the advantage of emitting less carbon dioxide during its manufacture compared to conventional products.

[0072] 〔summary〕 A first aspect of the present invention is a method for producing lithium chemical products from solid waste generated when producing boron chemical products from ore containing boron, which includes a step of mixing sulfuric acid of 25% by mass to 35% by mass with the solid waste at room temperature to extract lithium compounds in the solid waste as lithium ions. According to the first aspect, a new technology can be provided that uses a minimum amount of acid and can reduce costs in recovering lithium from solid waste.

[0073] The second aspect of the present invention uses sulfuric acid of more than 26% by mass and not more than 34% by mass relative to the solid waste in the first aspect. Also, the third aspect of the present invention uses sulfuric acid of 28% by mass or more and not more than 33% by mass relative to the solid waste in the first or second aspect. The second aspect is more effective from the viewpoint of sufficiently increasing the recovery efficiency of lithium, and the third aspect is even more effective from the viewpoint.

[0074] A fourth aspect of the present invention is any one of the first to third aspects, further comprising a step of wetting the solid waste with water before mixing with sulfuric acid. The fourth aspect is even more effective in terms of increasing the contact between the sulfuric acid and the solid waste in the extraction step.

[0075] The fifth aspect of the present invention further includes, in any one of the first to fourth aspects, a step of removing solid matter from the aqueous slurry mixed with sulfuric acid after the extraction of lithium ions, and a step of contacting the liquid medium (e.g., water containing impurities) after the removal of the solid matter with an adsorbent to adsorb only the lithium ions in the liquid medium to the adsorbent. In the fifth aspect, it is possible to proceed directly to the adsorption step without adjusting the pH after the removal of the solid matter. Therefore, the fifth aspect is even more effective from the viewpoint of simplification of the process and cost reduction.

[0076] A sixth aspect of the present invention is the fifth aspect, further comprising a step of contacting the adsorbent having lithium ions adsorbed thereon with an acid to elute the lithium ions from the adsorbent. In the sixth aspect, the removal of impurities by alkalizing can be performed simultaneously with neutralization to prevent corrosion of the evaporative concentration tank. Therefore, the sixth aspect is more effective in terms of improving the quality of the lithium chemical product, which is the final product, and improving the production efficiency.

[0077] The sixth aspect of the present invention may further include a step of making the eluate alkaline by adding an alkaline agent to the obtained eluate, a step of removing insoluble matter precipitated in the obtained alkaline eluate, a neutralization step of adjusting the pH of the eluate from which the insoluble matter has been removed to pH 5 to 8, and a step of concentrating the neutralized eluate. Including such additional steps is even more effective from the viewpoints of preventing corrosion of the device, improving the purity of lithium, and suppressing cost increases.

[0078] A seventh aspect of the present invention is a method for producing lithium chemical products from solid waste generated when producing boron chemical products from ore containing boron, the method comprising the steps of: pulverizing lump-shaped solid waste; mixing the pulverized solid waste with water to wet the solid waste with water; mixing sulfuric acid of 25% by mass or more and 35% by mass or less with respect to the dry solid waste with the solid waste at room temperature to extract lithium in the solid waste as lithium ions; removing solid matter from the lithium ion extract; contacting the lithium ion extract from which the solid matter has been removed with an adsorbent to adsorb the lithium ions onto the adsorbent; and contacting the adsorbent with the lithium ions adsorbed with an acid to elute the lithium ions from the adsorbent. The method includes, in this order, a step of adding an alkali to the obtained eluent to adjust the pH of the eluent to 6 or more, a step of concentrating the neutralized eluent, a step of adding a carbonate compound to the obtained concentrated solution to precipitate lithium carbonate, a step of separating the precipitated lithium carbonate particles from the concentrated solution and washing them with a saturated lithium carbonate aqueous solution, and a step of drying the washed lithium carbonate particles. The seventh embodiment is configured by a step that does not include roasting. Therefore, the seventh embodiment is more effective in terms of improving the quality of the lithium chemical product, which is the final product, and reducing the production cost and the total carbon dioxide emissions (LCA) of the production process.

[0079] The eighth aspect of the present invention is the seventh aspect, in which sulfuric acid having a concentration of more than 26 mass% and not more than 34 mass% is used. Also, the ninth aspect of the present invention is the seventh or eighth aspect, in which sulfuric acid having a concentration of 28 mass% or more and not more than 33 mass% is used. The eighth aspect is more effective from the viewpoint of sufficiently reducing the cost of recovering lithium with a small amount of acid, and the ninth aspect is even more effective from the viewpoint.

[0080] A tenth aspect of the present invention is any one of the fifth to ninth aspects, in which the solid waste contains calcium in the largest amount by mass among elements with atomic numbers of 12 or more. The tenth aspect is even more effective in terms of enabling the use of sulfuric acid that brings the pH of the liquid medium in the step after the extraction step to an appropriate pH that does not require neutralization.

[0081] In an eleventh aspect of the present invention, in any one of the first to tenth aspects, a manganese oxide-based ion adsorbent molded into pellets is used as the adsorbent. The tenth aspect is even more effective in terms of preventing the adsorbent from flowing out of the adsorption tube during liquid flow.

[0082] A twelfth aspect of the present invention is a lithium chemical product produced by the method for producing a lithium chemical product according to any one of the first to eleventh aspects. The twelfth aspect is even more effective in terms of realizing a lithium chemical product with a low LCA of CO2.

[0083] A thirteenth aspect of the present invention is a lithium ion battery or an all-solid-state battery manufactured using the lithium chemical product of the twelfth aspect as a material. The thirteenth aspect is even more effective in terms of achieving said battery with a low LCA of CO2.

[0084] A fourteenth aspect of the present invention is an electric vehicle equipped with the battery of the thirteenth aspect. The fourteenth aspect is even more effective in terms of realizing an electric vehicle with a low LCA of CO2.

[0085] According to the above-mentioned configuration, it is possible to contribute to the profit of the company by reducing the cost of medicines and other expenses, and at the same time, it is possible to contribute to reducing the burden on the global environment by reducing the LCA. Furthermore, by using the product of the present invention as a lithium chemical product, the LCA of CO2 of the lithium ion battery or the all-solid-state battery can be further reduced, and further the LCA of the electric vehicle using the battery can also be further reduced. The present invention, which can achieve such effects, is expected to contribute to the achievement of, for example, Goal 13 "Take urgent measures against climate change" of the Sustainable Development Goals (SDGs) advocated by the United Nations.

[0086] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in the different embodiments are also included in the technical scope of the present invention. EXAMPLES

[0087] An embodiment of the present invention will now be described.

[0088] Example 1 [Preparation of solid waste] Solid waste was prepared from the site of a boron chemical manufacturing plant in Kirka, Turkey. The solid waste is solid or muddy waste that is discharged as a residue when boron chemicals are manufactured from boron-containing minerals. The lithium concentration in the solid waste is approximately 800 ppm. The lithium concentration in the solid waste was measured by completely dissolving 1 g of sample in 10 mL of aqua regia and using atomic absorption spectrometry with the standard addition method (n=3).

[0089] Additionally, elemental analysis of the solid waste was performed using an energy dispersive X-ray fluorescence spectroscopy (EDX) analyzer. With this analysis method, elements with elemental numbers of 12 or higher are detected. The detection results are shown in Table 1. The abundances (%) in Table 1 were calculated from the abundances of elements with elemental numbers of 12 or higher. Furthermore, the X-ray diffraction results of the solid waste are shown in Figure 2. In Figure 2, the vertical axis represents relative reflection intensity, and the horizontal axis represents 2θ (θ is the X-ray incidence glancing angle). Among the peaks read from Figure 2, the relative intensities of the peaks with the largest relative intensity down to the 12th peak are shown in Table 2.

[0090] [Table 1]

[0091] [Table 2]

[0092] From Table 1, it can be seen that calcium (Ca) is the most abundant element with an atomic number of 12 or more. It can also be seen from Table 1 that silicon (Si) is contained in a significant amount (10% or more) and that magnesium (Mg) is not contained.

[0093] Furthermore, Figure 2 and Table 2 show that the top three peaks are prominent and distinctive.

[0094] [Lithium chemical manufacturing] First, the solid waste was crushed using an alumina mortar and pestle, and then sieved. The particle size of the resulting crushed material was approximately 450 μm or less in terms of major axis.

[0095] Next, about 1 kg of water was added to 1 kg of the pulverized solid waste, and the mixture was mixed and kneaded for 1 hour in a room temperature (20 to 30° C.) environment to obtain a water slurry of the pulverized material.

[0096] Next, 0.3 kg of concentrated sulfuric acid (30% by mass relative to the solid waste) having a concentration of 98% by mass (18 mol / L) was gradually added to the water slurry, and the mixture was further kneaded.

[0097] After the foaming from the water slurry had subsided, further water was added to the water slurry, and the slurry was filtered to separate the acid-treated pulverized material from a filtrate containing lithium.

[0098] Next, water was further added to the filtrate containing the separated lithium in an amount such that the lithium concentration became about 200 ppm. The pH of the diluted filtrate was measured and confirmed to be 6 or higher.

[0099] Next, the diluted filtrate was supplied to an adsorption tube (hereinafter also referred to as "lithium ion adsorption tube") filled with a pellet-shaped lithium ion adsorbent (lithium adsorbent described in International Publication No. 2011 / 058841) and allowed to flow. The presence of lithium ions in the liquid discharged from the lithium ion adsorption tube was measured using atomic absorption spectrometry. When it was confirmed that lithium ions were detected in the liquid discharged from the lithium ion adsorption tube, the supply of the diluted filtrate to the lithium ion adsorption tube was stopped.

[0100] Next, an aqueous solution of hydrochloric acid of about 1 mol / L (about 4%) was supplied to the lithium ion adsorption tube and allowed to flow. The lithium ions adsorbed on the lithium ion exchange adsorbent in the lithium ion adsorption tube were exchanged with hydrogen ions of hydrochloric acid (elution), and an aqueous solution of lithium chloride containing lithium chloride and hydrochloric acid (eluent) was discharged from the lithium ion adsorption tube.

[0101] Next, sodium hydroxide was added to the eluent to neutralize the hydrochloric acid and raise the pH to 10 or higher. By doing so, the trace amounts of calcium contained in the eluent and the trace amounts of manganese that had been dissolved from the adsorbent by the acid were precipitated. After filtering, the pH was adjusted to 6 to 8, and a highly pure eluent was obtained.

[0102] Next, the eluate was concentrated using an evaporative concentrator until the lithium ion concentration became 15,000 ppm or more, to obtain a concentrated solution of lithium chloride.

[0103] Next, about 210 g of sodium carbonate per 1 L of the concentrated liquid was added, stirred, and allowed to stand to produce and precipitate lithium carbonate.

[0104] Next, the precipitated lithium carbonate particles were taken out and washed with a saturated lithium carbonate aqueous solution. Thus, a refined lithium carbonate product with a purity of 99.7% or more was obtained as a lithium chemical product. In addition, the ratio of the lithium content of the refined lithium carbonate product to the lithium content of the solid waste was calculated to obtain the recovery rate of lithium from the solid waste. As a result, the recovery rate of lithium in this example was 95%.

[0105] The results of elemental analysis of the metal elements in the refined lithium carbonate product of this example are shown in Table 3. The remainder is lithium ions (Li + ).

[0106] [Table 3]

[0107] From Table 3, it can be seen that the obtained refined lithium carbonate has a sufficiently low concentration of impurities such as manganese, aluminum, or boron, which are avoided as a raw material for lithium ion batteries, and has a purity of 99.7% or more. The purity of lithium carbonate required as a raw material for lithium ion batteries is 99.5% or more. Therefore, the refined lithium carbonate obtained in this example can be used as a raw material for lithium ion batteries.

[0108] Comparative Example 1 Instead of concentrated sulfuric acid, 200 mL of 0.25 M hydrochloric acid was added per 1 g of the pulverized solid waste prepared in Example 1, and the aqueous slurry was mixed, kneaded, and filtered. Thus, a lithium extract of Comparative Example 1 was obtained by extracting lithium from the pulverized solid waste.

[0109] Comparative Example 2 The crushed solid waste prepared in Example 1 was roasted at 1100°C for 2 hours, immersed in water in an amount 2.7 times the mass of the roasted crushed material, and filtered. Thus, a lithium extract of Comparative Example 2 was obtained by extracting lithium from the crushed material after roasting.

[0110] Comparative Example 3 50 g of the pulverized solid waste prepared in Example 1 was moistened with water, 4.5 g of sulfuric acid (concentration 98 mass%) was added, mixed well, and roasted at 750°C for 1 hour. After cooling, 100 ml of water was added to perform water extraction, and the mixture was filtered. Thus, a lithium extract of Comparative Example 3 was obtained by extracting lithium from the pulverized material after roasting.

[0111] The amount of lithium in each of the lithium extract solutions in Comparative Examples 1 to 3 was quantified to determine the extraction rate of lithium from the solid waste. The lithium extraction rates in Example 1 and Comparative Examples 1 to 3 are shown in Table 4. Note that the lithium extraction rate in Example 1 in Table 4 uses the numerical value of the lithium recovery rate described above.

[0112] [Table 4]

[0113] As is clear from Table 4, in Example 1, the lithium extraction rate was high even though roasting was not performed.

[0114] As is clear from the comparison between Example 1 and Comparative Example 1, it is found that sulfuric acid is superior to hydrochloric acid in the extraction of lithium from solid pulverized material when the amount of addition is the same. The reason is unclear, but it is thought to be as follows. That is, in Example 1, water is added to the solid waste to the extent that it becomes a slurry, and then concentrated sulfuric acid is gradually added and kneaded. Although sulfuric acid is a divalent acid, at pH 1.5 or less, the concentration of monovalent hydrogen sulfate ions is higher than the concentration of divalent sulfate ions. Therefore, by directly adding concentrated sulfuric acid to the water slurry of solid waste, a period in which a large amount of hydrogen sulfate ions are present occurs in the process of diluting the concentrated sulfuric acid with the water in the slurry. It is presumed that these hydrogen sulfate ions efficiently extract lithium ions from the solid waste.

[0115] [Reference example] The amount of sulfuric acid added to the water slurry in Example 1 was measured at a mass ratio of sulfuric acid to the ground material of 0, 0.1, 0.2, 0.3 (Example), and 0.4, respectively, and the amount of lithium extracted into the liquid medium of the water slurry was measured. The results are shown in Figure 3.

[0116] As shown in Fig. 3, as the mass ratio of sulfuric acid to the pulverized material increases from 0 to about 0.2, the lithium extraction rate increases relatively slowly. Then, as the mass ratio increases from about 0.2 to about 0.3, the lithium extraction rate increases more rapidly. Then, at a mass ratio of 0.31, the lithium extraction rate becomes 100%, after which the lithium extraction rate plateaus. From Fig. 3, it can be seen that the mass ratio of sulfuric acid to the pulverized material is preferably in the range of about 0.25 to 0.35.

[0117] According to the above examples, it is clear that a new technology can be provided that can further reduce the recovery cost per unit weight of recovered lithium in recovering lithium from solid waste that we have obtained. [Industrial Applicability]

[0118] The present invention can be used to popularize lithium chemicals and further products derived therefrom, and can be used to reduce the environmental burden in the production of the lithium chemicals and further products derived therefrom.

Claims

1. 1. A method for producing lithium chemicals from solid waste resulting from the production of boron chemicals from boron-containing ores, comprising: A method for producing a lithium chemical product, comprising: mixing the solid waste with sulfuric acid at room temperature in an amount of 25% by mass or more and 35% by mass or less relative to the solid waste, thereby extracting lithium in the solid waste into a liquid medium.

2. 2. The method for producing lithium chemical products according to claim 1, wherein sulfuric acid is used in an amount of more than 26% by mass and not more than 34% by mass relative to the solid waste.

3. The method for producing lithium chemical products according to claim 1, wherein sulfuric acid is used in an amount of 28% by mass or more and 33% by mass or less relative to the solid waste.

4. 2. The method of claim 1 further comprising wetting the solid waste with water before mixing the sulfuric acid.

5. removing solids by solid-liquid separation after the lithium extraction; The method for producing a lithium chemical product according to claim 1, further comprising the step of contacting the liquid medium from which the solid matter has been removed with an adsorbent to adsorb the lithium in the liquid medium onto the adsorbent.

6. contacting the adsorbent having the lithium adsorbed thereon with an acid to elute the lithium from the adsorbent; adding an alkaline agent to the obtained eluate to make the eluate alkaline; removing insoluble matter precipitated in the resulting alkaline eluent; The method for producing a lithium chemical product according to claim 5, further comprising: a neutralizing step of adjusting the pH of the eluent from which the insoluble matter has been removed to pH 5 to 8; and a step of concentrating the neutralized eluent.

7. 1. A method for producing lithium chemicals from solid waste resulting from the production of boron chemicals from boron-containing ores, comprising: Breaking the solid waste into chunks; mixing water with the comminuted solid waste to wet the solid waste with water; A step of mixing sulfuric acid in an amount of 25% by mass or more and 35% by mass or less with respect to the solid waste at room temperature to extract lithium in the solid waste as lithium ions into a liquid medium; removing solids from the mixture of liquid medium and solid waste; a step of contacting the liquid medium from which the solid matter has been removed with an adsorbent to adsorb the lithium ions in the liquid medium onto the adsorbent; contacting the adsorbent having the lithium ions adsorbed thereon with an acid to elute the lithium ions from the adsorbent; adding an alkali to the obtained eluate to adjust the pH of the eluate to 6 or more; concentrating the eluate having a pH of 6 or more; A step of adding a carbonate compound to the obtained concentrated liquid to precipitate lithium carbonate; Separating the precipitated lithium carbonate particles from the concentrated solution and then washing them with a saturated aqueous lithium carbonate solution; and drying the washed lithium carbonate particles.

8. The method for producing lithium chemical products according to claim 7, wherein sulfuric acid is used in an amount of more than 26% by mass and not more than 34% by mass relative to the solid waste.

9. The method for producing lithium chemical products according to claim 7, wherein sulfuric acid is used in an amount of 28% by mass or more and 33% by mass or less relative to the solid waste.

10. 8. The method for producing a lithium chemical product according to claim 5 or 7, wherein a manganese oxide-based ion adsorbent formed into pellets is used as the adsorbent.

11. The method for producing a lithium chemical product according to claim 1 or 7, wherein the solid waste contains calcium in the largest amount by mass among elements with atomic numbers of 12 or more.

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