Method and apparatus for converting α-spodumene into β-spodumene, in particular for simplified lithium extraction from minerals

Abstract

Method for converting α-spodumene into β-spodumene, wherein the α-spodumene is converted into the β-spodumene by heating α-spodumene-containing material (M1) to a predetermined conversion temperature, wherein the α-spodumene-containing material (M1) is heated to the predetermined conversion temperature by means of laser irradiation, wherein the α-spodumene-containing material (M1) is supplied to the laser irradiation as a material stream by means of a conveying device (4), wherein the material stream is guided in free fall past a laser beam device (2) which performs the laser irradiation, and wherein the α-spodumene-containing material (M1) is laser-irradiated from opposite sides of the material stream.

Description

[0001] The invention relates to a method for converting α-spodumene into β-spodumene according to the features of claim 1 and a device for carrying out the method.

[0002] As described in DE 10 64 935 B, a process for producing lithium sulfate from spodumene is known from the prior art. This process involves an exchange reaction carried out in an acidic medium below 600 °C, which does not cause the spodumene to melt, and leaching of the lithium sulfate formed from the reaction mass. The gangue-contaminated, comminuted spodumene ore, converted from α-spodumene to β-spodumene, is reacted with steam and gaseous SO3 or steam and a catalytically activated gas mixture of SO3-containing SO2 and air in a gas-solid reaction without the formation of a liquid phase. To convert α-spodumene into β-spodumene, the minerals or their concentrates are heated to a temperature above the conversion temperature of α-spodumene to β-spodumene, i.e. above 1000 °C, but not above the melting temperature of the accompanying minerals.

[0003] CN 1 02 433 430 A relates to a process for the production of β-spodumene concentrates by the action of microwaves on crude spodumene ores.The process comprises the following steps: crushing the crude spodumene ores to achieve a particle size of 0.2–30 mm to obtain crushed materials; heating the crushed materials at a temperature of 930–1050 °C for 30–50 minutes using microwaves and natural cooling to a temperature not exceeding 60 °C; performing primary sieving on the obtained crushed materials to obtain oversize and undersize products, namely β-spodumene concentrates I, with a mesh size of 0.2 mm; and milling the obtained oversize products to achieve a particle size of 0.1–10 mm, performing secondary sieving to obtain the oversize and undersize products, namely β-spodumene concentrates II, with a mesh size of 0.2 mm. and mixing the β-spodumene concentrates I with the β-spodumene concentrates II to obtain the β-spodumene concentrates.

[0004] Mönch and Derra (MÖNCH, H., DERRA, G.: High Power VCSEL Systems - A tool for digital thermal processing. In: Laser Technik Journal, Vol. 11, 2014, No. 2, pp. 43-47. -ISSN 2626-1308) describe in their article, among other things, the application of high-power VCSEL systems (VCSEL: vertical-cavity surface-emitting laser) in the structural transformation of materials.

[0005] DE 10 2014 006 942 B3 relates to a process for producing sand suitable for concrete production or as bulk material for land reclamation by thermal treatment using round, smooth mineral grains in the form of desert sand grains as a starting material, in which the starting material is melted as a thin layer on a conveyor belt by means of a laser.

[0006] DE 100 55 743 A1 relates to a process for drying and / or calcining a bulk material, in particular a pigment powder, food or spice product, or planar particles obtained from a suspension, wherein the bulk material is transported essentially continuously as a layer on a carrier or as a trickle stream through an infrared radiation field, the main active component of which lies in the near-infrared range, in particular in the wavelength range between 0.8 µm and 1.5 µm. The temperature of the trickle stream is measured using a radiation pyrometer.

[0007] The invention is based on the objective of providing a method for converting α-spodumene into β-spodumene that is improved compared to the prior art, and a device for carrying out the method.

[0008] The problem is solved according to the invention by a method for converting α-spodumene into β-spodumene with the features of claim 1 and a device for carrying out the method with the features of claim 3.

[0009] Advantageous embodiments of the invention are the subject of the dependent claims.

[0010] In a process for converting α-spodumene to β-spodumene, particularly for the simplified extraction of lithium from minerals, the α-spodumene is converted to β-spodumene by heating α-spodumene-containing material to a predetermined conversion temperature, preferably 1000 °C or at least 1000 °C. In nature, spodumene exists as α-spodumene, i.e., in the stable α-monoclinic form. By heating to the predetermined conversion temperature, it can be converted into the β-tetragonal form, i.e., into β-spodumene.

[0011] According to the invention, the material containing or exhibiting α-spodumene is heated to the predetermined transformation temperature by means of laser irradiation. The α-spodumene-containing material is, in particular, crushed rock, especially in the form of rock particles.

[0012] According to the invention, the material containing α-spodumene is supplied to the laser irradiation as a material stream by means of a conveying device.

[0013] According to the invention, the material flow is guided in free fall past a laser beam device that carries out the laser irradiation.

[0014] According to the invention, the material containing α-spodumene is laser-irradiated from opposite sides of the material stream.

[0015] An apparatus according to the invention for carrying out the method comprises a laser beam device with several laser beam generators, wherein the laser beam device is configured for laser irradiation of the material containing α-spodumene in order to heat it to the predetermined conversion temperature and thereby convert the α-spodumene into β-spodumene. The apparatus according to the invention includes a conveying device. The laser beam generators and the conveying device are arranged such that the material flow can be guided between and past the laser beam generators by means of the conveying device.

[0016] The solution according to the invention enables a simpler and more energy-efficient extraction of lithium. Lithium is needed, for example, in large quantities for traction batteries to power electric drive motors in vehicles. Currently, lithium extraction is very energy-intensive and, in some cases, environmentally damaging. High water consumption is particularly problematic when extracting lithium from brine. To avoid this high water consumption, lithium can be extracted from minerals. However, this has so far been associated with high energy consumption and a corresponding generation of carbon dioxide.

[0017] The solution described here can significantly reduce this energy consumption and carbon dioxide emissions. For lithium extraction, the mineral lithium compound known as spodumene is used as a precursor. Currently, spodumene is primarily mined in Australia. The intermediate products derived from it are further processed mainly in China. Transport incurs additional high costs and carbon dioxide emissions, as only 6% of the transported material is lithium; the rest consists of unusable byproducts.

[0018] Currently, spodumene is processed, for example, using the acid roasting method to concentrate the lithium. This requires the mineral to be heated to over 1000 °C in a first step to change its crystal structure from α to β. This is currently done in large furnaces powered by oil or gas burners, which are harmful to the climate. The necessary fuel also has to be transported to the spodumene mining or processing site. Alternatively, microwave heating methods have been investigated, but these have the disadvantage that microwaves do not couple directly into the original α-spodumene crystal; instead, other substances, such as silicon carbide, must be added. Furthermore, microwaves couple more readily into the converted β-crystal structure, leading to undesirable melting and a subsequent loss of the crystal structure.

[0019] Electrically operated furnaces are now also being described that use electrically heated metal or ceramic elements to heat the material and / or gases / air, thus at least locally eliminating carbon dioxide emissions. The main disadvantages are the longer reaction times required for the conversion, as the material is heated solely through thermal conduction of the surrounding gases and irradiation by infrared radiation, which, unlike laser radiation, is unfocused, incoherent, and comparatively low in intensity. Further disadvantages include the wear and tear and limited lifespan of the heating elements, as well as the necessary, complex thermal insulation of the reaction vessel, since the surrounding area is also significantly heated.

[0020] The disadvantages and problems of previously used and investigated methods for converting α-spodumene to β-spodumene are overcome by the solution described here, in which the α-spodumene-containing material is heated to the predetermined conversion temperature by means of laser irradiation, in particular by means of planar laser irradiation. For this purpose, several, especially planar, laser beam generators are used. The laser radiation enables a very targeted, controlled, or regulated energy input into the material. In contrast to heating the material in an oven, the surrounding area of ​​the material is not heated or only heated minimally. In the solution according to the invention, the energy used is thus employed particularly efficiently and with very low losses for the conversion of α-spodumene to β-spodumene.

[0021] The laser radiation from several laser beam generators is directed onto the surface of a layer of material containing α-spodumene, particularly in a granulated form, and is absorbed there. High beam quality requirements are not necessary for this process. Therefore, for example, arrays of inexpensive conventional laser diodes or surface emitters can be used, which can then be focused with simple optical elements.

[0022] For example, laser beam generators of the laser beam device comprise at least one array of laser diodes or surface emitters, i.e., in particular, several laser diodes or surface emitters arranged in series and / or side by side. The laser diodes are, in particular, edge-emitting laser diodes, in which the light is emitted from one or two edges of a semiconductor chip. The surface emitters are also referred to as VCSELs (vertical-cavity surface-emitting lasers). Such a surface emitter is a laser diode in which the light is emitted approximately perpendicular, preferably perpendicular, to the plane of the semiconductor chip.

[0023] Alternatively, the laser beam generators of the laser beam device can, for example, be a fiber-guided system, i.e., comprising at least one laser light source and at least one optical waveguide, in particular a fiber optic waveguide. The laser radiation, which is typically provided as a point source in such fiber-guided systems, can then be spread over an area, for example, by means of optical elements, such as at least one lens or at least one grating. Alternatively or additionally, such laser radiation can be moved rapidly across the surface of the material, for example, by means of a scanner system, so that quasi-area irradiation is also achieved. Such scanner systems are already known from other laser applications.

[0024] To further reduce carbon dioxide emissions, the laser beam device is powered by solar and / or wind energy, preferably locally, i.e., at the site where the process is carried out. The device can therefore, for example, include solar cells and / or at least one wind turbine and / or one or more other renewable energy sources to generate electricity for the laser beam device. For example, the generated electricity can be used as direct current (DC) for the laser beam device, as DC is required for this purpose. This eliminates the need for lossy conversion to alternating current (AC).

[0025] The laser irradiation is directed onto a layer of the material containing α-spodumene, particularly when pulverized, causing it to heat up very rapidly, primarily through direct absorption of the laser radiation at the material's surface. A rough and fractured surface, as is typical for ground rock, promotes the absorption of laser energy through multiple absorption. Since the change in lattice structure usually occurs very rapidly upon reaching the appropriate temperature, the laser irradiation only needs to continue until even the internal regions of a rock grain have reached this temperature through heat conduction. Due to the precise controllability of the heat input via the aforementioned process parameters, this duration can be limited to the minimum necessary interval using a laser.In contrast, all furnace processes that are partially or completely based on heat conduction also involve the heat transfer from the heated surrounding gas to the rock grains, which usually has to be supported by mixing / stirring the material or kinetic movement of the hot gases.

[0026] The laser intensity can be predefined or selected to prevent any melting of the material's surface. Alternatively, minimal melting is accepted, which increases the absorption of the laser radiation and can lead to a higher overall surface temperature, thus promoting faster transformation of the entire rock grain. However, this can reduce the β-spodumene yield if the liquefied material does not solidify in the β-structure, which depends on the process parameters.

[0027] For example, the current heating temperature is determined by means of at least one temperature sensor, in particular a pyrometer. This enables control and / or regulation of the current heating temperature to ensure that the predetermined conversion temperature is reached. In one possible embodiment, the device for carrying out the method therefore includes this temperature sensor, in particular the pyrometer.

[0028] According to the invention, the material containing α-spodumene is fed to the laser irradiation as a material stream by means of a conveying device. The device according to the invention includes this conveying device.

[0029] The conveying device is designed, for example, as a conveyor belt, a screw conveyor, a pneumatic conveyor, a hopper, or a nozzle, or comprises at least one of these components. The material flow is guided in free fall past the laser beam device that carries out the laser irradiation, for example, via the conveyor belt or another conveying device, or falls through the hopper or nozzle past the laser beam device and is thereby irradiated by the laser.

[0030] The exposure time per volume element of the material containing α-spodumene is set, for example, by an irradiation area and / or by a series of several laser beam generators. The intensity on the α-spodumene-containing material, and thus the temperature or temperature profile, is set, for example, by adjusting the laser power and / or the strength of the focus, and thus the power density. This optimizes the process steps for optimal temperatures or temperature profiles, particularly with regard to the specified conversion temperature. However, the device and the method for heating by laser irradiation can be used not only for the conversion of α-spodumene to β-spodumene, but also, for example, for other lithium extraction processes that also require high temperatures.

[0031] According to one aspect of the process, in particular to ensure the specified conversion temperature, the material flow and / or the irradiation area of ​​the laser irradiation and / or the laser power of the laser irradiation and / or the strength of the focusing of the laser irradiation are controlled and / or regulated depending on the determined current heating temperature.

[0032] The material containing α-spodumene is laser-irradiated from opposite sides of the material flow. "Opposite side of the material flow" refers specifically to a surface face of the material flow. That is, the material flow is irradiated at a right angle or at an oblique angle to the flow direction present at the point of laser irradiation. "Opposite sides of the material flow" refers accordingly to the opposite surfaces of the material flow.

[0033] The laser beam generators and the conveying device are arranged such that the material flow can be guided between the laser beam generators by means of the conveying device and past them in free fall. For example, the conveying device, such as the nozzle or the hopper, or the falling of the material containing α-spodumene at the end of the conveyor belt, generates a directed material flow or material beam that moves between the laser beam generators.

[0034] To prevent mutual laser irradiation of opposing laser beam generators in the event of gaps in the material flow or a complete absence of material flow, and the resulting risk of damage, the laser beam generators, or at least the laser radiation emitted by each laser beam generator, are aligned at an angle to the material flow that deviates from 90°. This means that each laser beam generator and the laser radiation emitted by it are not directed at the opposing laser beam generator, but rather past it. For example, in the case of a vertically falling material flow, each laser beam generator and the laser radiation emitted by it are thus aligned diagonally downwards or upwards, but always in the direction of the material flow.

[0035] The described solution allows for direct heating only of the material containing α-spodumene and not of the surrounding environment. This disadvantage of heating in furnaces is thus avoided by the described solution.

[0036] The described solution does not require high-frequency shielding, which is necessary when heating by microwaves.

[0037] The described solution advantageously allows for precise control of the temperature or temperature profiles. This enables optimization of the crystal transformation of α-spodumene to β-spodumene. As already described, the device and the procedure for heating by laser irradiation can also be used, for example, for further process steps in lithium production.

[0038] As described, it is advantageous to provide for the electricity required for laser irradiation to be generated emission-free, for example, using at least one wind turbine and / or solar cells. This eliminates the need for fossil fuels for electrical power supply in the process and the device. This avoids corresponding carbon dioxide emissions and also results in cost advantages. Furthermore, the electricity generated in this way can be used immediately and therefore particularly efficiently. For example, no conversion and storage are required. Thus, the described solution is also more efficient than converting renewable electricity into hydrogen and burning it to generate heat for furnaces in which the α-spodumene-containing material is heated. Moreover, this conversion of electricity into hydrogen via electrolysis requires water.Such water consumption can also be avoided with the described solution.

[0039] The described solution enables, in particular, the further processing of the α-spodumene-containing material directly at or near the mining site. This avoids longer material transports and the associated carbon dioxide emissions.

[0040] Another advantage of the described solution is that, unlike rotary kilns, which are currently used to heat the α-spodumene-containing material for conversion to β-spodumene, the laser beam generators are wear-free, or at least virtually wear-free. This eliminates the corresponding maintenance effort and costs.

[0041] The described solution can in principle also be applied to other lithium-containing minerals, where an advantageous change or reformation of the lattice structure can be produced by heating to a transformation temperature below the melting temperature or by partial or complete remelting / re-melting near the melting temperature.

[0042] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0043] This shows: Fig. 1 schematically an embodiment of a device not according to the invention for carrying out a method for converting α-spodumene into β-spodumene, Fig. 2 schematically a further embodiment of the device not according to the invention, Fig. 3 schematically an embodiment of the device according to the invention for carrying out the method according to the invention, Fig. 4 schematically shows another embodiment of the device according to the invention, and Fig. 5 schematically shows another embodiment of the device according to the invention.

[0044] Corresponding parts are marked with the same reference symbols in all figures.

[0045] The Fig. 1 and Fig. Figure 2 shows, in a highly simplified schematic fashion, two embodiments of a device not according to the invention for carrying out a method for converting α-spodumene into β-spodumene. Fig. 3, Fig. 4 to Fig. Figure 5 shows, by way of example and in a highly simplified schematic fashion, various embodiments of the device 1 according to the invention for carrying out the process according to the invention for converting α-spodumene into β-spodumene. These schematic representations illustrate in particular the basic principles of the process and the device 1 for carrying it out, which are described in more detail below.

[0046] Spodumene contains lithium, which is needed in large quantities, for example, for traction batteries that supply electrical energy to electric motors in vehicles. In nature, spodumene occurs as α-spodumene. To extract the lithium, it must be converted into β-spodumene. In the process described here, α-spodumene is converted into β-spodumene by heating α-spodumene-containing material M1 to a predetermined conversion temperature, in the range of approximately 950 °C to 1050 °C, preferably 1000 °C, using laser irradiation. The α-spodumene-containing material M1 is, in particular, crushed rock, especially in the form of rock particles. After laser irradiation of the α-spodumene-containing material M1, β-spodumene-containing material M2 is obtained, which can then be further processed to extract lithium.

[0047] The solution described here, i.e., heating by means of at least one laser irradiation, enables a simpler and more energy-efficient extraction of lithium.

[0048] Based on the Fig. 1 and Fig. Section 2 below explains the fundamental aspects of heating by means of laser irradiation. The device 1 comprises a laser beam device 2 with one or more laser beam generators 3, wherein the laser beam device 2 is configured for laser irradiation of the α-spodumene-containing material M1 in order to heat it to a predetermined or predefined conversion temperature and thereby convert the α-spodumene into the β-spodumene. Each laser beam generator 3 comprises, in particular, at least one laser beam source and a beam shaping device, especially a focusing optic.

[0049] The α-spodumene-containing material M1 is heated to the predetermined conversion temperature, particularly by means of planar laser irradiation. For this purpose, one or more laser beam generators 3, especially planar ones, can be used. The laser radiation S enables a highly targeted, controlled, or regulated energy input into the α-spodumene-containing material M1. The energy input is thus used particularly efficiently and with very low losses to convert the α-spodumene into the β-spodumene.

[0050] There are no high requirements for beam quality. Therefore, for example, arrays of inexpensive conventional laser diodes or surface emitters can be used, which can then be focused with simple optical elements.

[0051] Thus, a laser beam generator 3 of the laser beam device 2 can comprise at least one array of laser diodes and / or surface emitters. Alternatively, the at least one laser beam generator 3 of the laser beam device 2 can, for example, be a fiber-guided system, i.e., in particular, comprise at least one laser light source and at least one optical fiber, in particular a fiber optical fiber.

[0052] The laser beam device 2 of the in Fig. The device 1 shown in Figure 1 has several individual laser beam generators 3 or fiber-guided lasers with focusing optics, each of which generates line-shaped laser beams S. The laser beam device 2 of the in Figure 1 Fig. The device 1 shown in Figure 2, which is not according to the invention, has a planar laser beam generator 3, for example with one or more diode laser arrays or vertically emitting lasers, i.e., surface emitters (VCSELs). This achieves quasi-planar laser irradiation by superimposing individual beams. The laser beam generators 3 of the laser beam device 2 shown in the Fig. 3, Fig. 4 to Fig. The embodiments shown in 5 can, for example, be designed as in Fig. 1 or as in Fig. 2, i.e., in particular as several individual lasers or as a planar laser.

[0053] For example, the current heating temperature is determined by means of at least one temperature sensor, in particular a pyrometer. This enables control and / or regulation of the current heating temperature to ensure that the predetermined conversion temperature is reached. The device 1 for carrying out the method thus includes, in one possible embodiment, this temperature sensor, in particular the pyrometer. Fig. 1, Fig. 2, Fig. 3, Fig. 4 to Fig. This is not shown in section 5.

[0054] In the embodiment according to the invention in the Fig. 3. The α-spodumene-containing material M1 is fed to the laser irradiation as a material stream by means of a conveying device 4. The device 1 thus includes this conveying device 4.

[0055] The conveying device 4 is designed as a conveyor belt 5 or comprises such a conveyor belt 5, as shown in the Fig. 3 shown. The conveying device comprises 4 in the example according to the Fig. 3 also, for example, a screw conveyor, screw conveyor, pneumatic conveyor, hopper or a nozzle 6 for supplying Z the material M1 containing α-spodumene, which is designed as crushed rock, to the conveyor belt 5. In the embodiments according to the Fig. 4 and Fig. For example, if the conveying device 4 does not have a conveyor belt 5, but only a screw conveyor, screw conveyor, pneumatic conveyor, hopper or nozzle 6, then the conveying device 4 has a conveyor belt 5.

[0056] According to the invention, the material flow is in free fall, as in the Fig. 3, Fig. 4 to Fig. 5 shown, passing by the laser beam device 2 that carries out the laser irradiation, for example via the conveyor belt 5, or via the nozzle 6 or another conveying device 4, as shown in the Fig. 4 and Fig. 5 shown. In the Fig. 1 and Fig. 2 According to a non-inventive aspect, the material flow on the conveyor belt 5 is moved past the laser beam device 2 which carries out the laser irradiation, as shown in Fig. 1 is illustrated by means of a conveyor belt movement arrow FP, and is thereby illuminated by a laser. In the Fig. 3, Fig. 4 to Fig. 5. The material flow passes by the laser beam device 2 that performs the laser irradiation, as shown in Fig. 3 is illustrated by means of a material movement arrow MP, and is thereby laser-irradiated.

[0057] The exposure time per volume element of the α-spodumene-containing material M1 can be set, for example, by an irradiation area and / or by connecting several laser beam generators 3 in series. The intensity on the α-spodumene-containing material M1, and thus the temperature or temperature profile, can be set, for example, by adjusting the laser power and the focusing strength, and thus the power density. This allows for optimization to achieve optimal temperatures or temperature profiles, particularly with regard to the specified conversion temperature.

[0058] In this process, particularly to ensure the specified conversion temperature, the material flow and / or the irradiation area of ​​the laser irradiation and / or the laser power of the laser irradiation and / or the strength of the focusing of the laser irradiation are controlled and / or regulated depending on the determined current heating temperature.

[0059] In the embodiments of the devices not according to the invention, the following applies: Fig. 1 and Fig. 2 The α-spodumene-containing material M1 is laser-irradiated from one side of the material stream, here from above, while it is conveyed by the conveying device 4, in particular by the conveyor belt 5, especially under the laser beam device 2.

[0060] In the embodiments according to the invention, as described below, Fig. 3, Fig. 4 to Fig. 5. The α-spodumene-containing material M1 is laser-irradiated from several opposite sides of the material stream, while the α-spodumene-containing material M1, i.e., the material stream, falls freely through the laser beam device 2. For this purpose, in the illustrated examples, according to the Fig. 3, Fig. 4 to Fig. 5 The laser beam device 2 comprises several laser beam generators 3, wherein the laser beam generators 3 and the conveying device 4 are arranged such that the material flow can be guided between the laser beam generators 3 of the laser beam device 2 by means of the conveying device 4 and past them. This is achieved in the illustrated examples by generating a directed material flow or material beam through the conveying device 4, for example by means of the nozzle 6 or the hopper, or by the material M1 containing the α-spodumene falling at the end of the conveyor belt 5, which moves between the laser beam generators 3.

[0061] To prevent mutual laser irradiation of the opposing laser beam generators 3 in the event of gaps in the material flow or in the absence of a material flow, and the resulting risk of damage, the embodiments according to the Fig. 4 and Fig. 5. The laser beam generators 3, or at least the laser radiation S emitted by each laser beam generator 3, are aligned at an angle χ to the material flow that deviates from 90°. This means that each laser beam generator 3, or the laser radiation S emitted by it, is not aligned with the opposite laser beam generator 3, but rather past it. For a vertically falling material flow, each laser beam generator 3, or the laser radiation S emitted by it, is thus, for example, directed obliquely downwards, as shown in the Fig. 4 and Fig. 5 shown, or angled upwards, but always in the direction of the material flow.

[0062] The features and advantages described herein relating to the method for converting α-spodumene into β-spodumene also apply to the apparatus described herein and vice versa. Reference symbol list 1 Device 2 Laser beam device 3 laser beam generators 4. Support facility 5 Conveyor belt 6 nozzle FP conveyor belt movement arrow M1 α-spodumene containing material M2 β-spodumene containing material MP Material Movement Arrow S Laser radiation Z Supply X angle

Claims

[1] Method for converting α-spodumene to β-spodumene, wherein the α-spodumene is converted to the β-spodumene by heating α-spodumene-containing material (M1) to a predetermined conversion temperature, wherein the α-spodumene-containing material (M1) is heated to the predetermined conversion temperature by means of laser irradiation, wherein the α-spodumene-containing material (M1) is supplied to the laser irradiation as a material stream by means of a conveying device (4), wherein the material stream is guided in free fall past a laser beam device (2) which performs the laser irradiation, and wherein the α-spodumene-containing material (M1) is laser-irradiated from opposite sides of the material stream. [2] Method according to claim 1, characterized by that the current heating temperature is determined using a pyrometer. [3] Device (1) for carrying out the method according to one of the preceding claims, comprising a conveying device (4) and a Laser beam device (2) with several laser beam generators (3), wherein the laser beam device (2) is configured for laser irradiation of the α-spodumene-containing material (M1) in order to heat it to the predetermined conversion temperature, wherein the laser beam generators (3) and the conveying device (4) are arranged such that the material flow between the laser beam generators (3) can be guided past them in free fall, and wherein the laser beam generators (3) are arranged such that the material flow can be laser-irradiated from opposite sides of the material flow. [4] Device (1) according to claim 3, characterized by that the multiple laser beam generators (3) each have an array of laser diodes or surface emitters.

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