Method and device for recycling silicon elements in particular from crystalline silicon

Abstract

The invention relates to a method and a device for recycling silicon elements, in particular from crystalline silicon, wherein, in a variant A, waste from silicon elements which comprise no metallic adhesions or, in a variant B, waste from silicon elements which comprise metals and / or adhesions such as graphite or quartz or, in a variant C, waste from silicon elements which comprise aluminium adhesions, are introduced into a reactor and reacted in the case of variant A with water and in the case of variants B and C with alkali hydroxide solution, with heat being generated and, in the case of variants A and B, hydrogen. The device has a reactor (R), in particular in the form of an autoclave, with the following components: a filler neck (1) for feeding comminuted waste (cell breakage) or non-comminuted waste, a heat exchanger (2), a stirring mechanism or agitator (3), a hydrogen outlet (4), a gas dryer (5), a compressor (6) downstream of the gas dryer, a gas accumulator (7) downstream of the compressor, a discharge valve (8), a filter (9) downstream of the discharge valve, in which the insoluble metals and / or other insoluble adhesions accumulate, and an outlet (10) for the filtered water glass solution.

Description

[0001] Method and device for recycling silicon elements, in particular crystalline silicon

[0002] The present invention relates to a method and a device for recycling silicon elements made in particular of crystalline silicon, according to the preamble of the first, fifth and sixth patent claims.

[0003] In particular, silicon cell scrap from solar modules with and without metallic adhesions, as well as silicon waste with graphite or quartz adhesions, are to be recycled.

[0004] The chemical abbreviation c-Si refers to crystalline silicon.

[0005] The statements, results, and conclusions presented below apply first and foremost to solar cells made of crystalline silicon and featuring metallic contacts. For the sake of simplicity, the following text will not distinguish them from other types of solar cells, such as dye-sensitized solar cells or compound semiconductor solar cells, but will refer to them simply as "solar cells."

[0006] Solar cells are electronic components that convert light energy into electrical energy. The net current flow generated by this light absorption can be made available to a consumer via metallic contacts, for example, silver and / or transparent conductive oxides (TCOs), such as indium tin oxide (ITO). The metallic contacts are usually constructed from delicate structures to minimize shadow losses. By minimizing this shadowing, the largest possible silicon surface area is utilized. Therefore, during production, the aim is to achieve very narrow and tall contact fingers, which may taper towards the edge of the solar cell. The metallic contacts are applied, for example, by screen printing using a silver paste.

[0007] Both the contacted c-Si solar cells from production, which become production waste due to breakage or quality defects, and the material awaiting recycling in decommissioned photovoltaic modules, cannot currently be fully and financially separated into individual fractions. Modern PV modules currently produced, using heterojunction technology (HJT) as an example, contain approximately 2.5% silicon but only 0.03% silver. This means that approximately 0.5 kg of silicon contains only approximately 6 g of silver. Considering the cell scrap alone, a silver content of 1.2% is already present in this case.

[0008] The separation of silver and silicon can be achieved through known reactions, such as those described in document DE102008024590B4 using nitric acid or in document EP000002984192B1 using hydrometallurgical treatment with organosulfonic acids. These processes focus on dissolving silver, for example, using nitric acid or organosulfonic acids. The resulting silver-containing solution naturally requires further treatment steps, which is not optimal from an ecological and economic perspective. The reaction with nitric acid also generates NO. X which are problematic for the environment and require expensive exhaust air treatment.

[0009] The publication DE102013112004B4 describes a recycling process for entire solar modules, in which silicon is to be electrochemically deposited from a solution resulting from the recycling process. However, there are considerable doubts about its feasibility. The lack of practical examples in the publication and the fact that there are apparently no references to scientific publications on the deposition of silicon from aqueous solutions lead to the assumption that the described process is not applicable at all.

[0010] Document JP2000191303 A describes a device capable of producing high-purity hydrogen at low cost by using large quantities of silicon waste generated during a semiconductor device manufacturing process.The hydrogen production apparatus is arranged adjacent to the semiconductor device manufacturing line and is equipped with a reaction vessel for conducting a hydrogen generation reaction by mixing an alkaline solution with silicon, a silicon supply device for collecting the silicon waste generated on the line and supplying it to the reaction vessel as raw material, an alkali solution supply device for supplying the alkali solution into the reaction vessel, a pressure control device for controlling the internal pressure of the reaction vessel, a temperature control device for controlling the alkali solution temperature to a prescribed temperature, and a hydrogen recovery device for returning gaseous hydrogen generated in the reaction vessel to the outside.

[0011] The disadvantage is the prior preparation of the alkali solution. Furthermore, metal-containing semiconductor waste cannot be processed.

[0012] The object of the invention is to develop a method and a device for recycling silicon elements made of crystalline silicon in particular, in particular c-Si solar cells, with which the silicon elements and any metal adhering thereto, e.g. silver and / or copper and / or aluminum or possibly also silicon waste with graphite or quartz or combinations thereof, can be separated directly or at least in a highly concentrated manner and with which utilization in the sense of recycling silicon elements, e.g. c-Si solar cells, can be carried out more economically.

[0013] This problem is solved by the features of the first, fifth and sixth patent claims.

[0014] Advantageous embodiments arise from the subclaims.

[0015] The term silicon elements includes, on the one hand, silicon cell scrap from solar cells in the form of silicon particles, material made of silicon, silicon particles and thus, for example, shards, fragments, powder, grains, the contacts or adhesions made of metal, for example silver, silver-coated copper, copper and / or aluminum, but also silicon waste which may contain graphite or quartz residues.

[0016] In the process for recycling silicon elements in the form of silicon cell bulkheads made of crystalline silicon in particular, three processes A, B and C are distinguished:

[0017] Variant A - without adhesions (pure silicon) or

[0018] Variant B - with adhesions that are insoluble in the process, such as silver, copper but also graphite or quartz or

[0019] Variant C - with aluminum deposits that are soluble according to the process.

[0020] According to the process, in variant A, waste from silicon elements which do not have any metallic adhesions is introduced into a reactor with water in which circulation takes place, and by direct reaction of the silicon with water, hydrogen and silicic acid are produced simultaneously and silicic acid and hydrogen are discharged from the reactor after the required reaction time, so that in the case that cell breakage is processed without contacts, the target product is silicic acid and hydrogen.

[0021] The silica can be further processed into silicon dioxide, for example.

[0022] In the case of waste from silicon elements which have insoluble metallic and / or other insoluble deposits according to variant B, these are introduced into a reactor with alkali hydroxide solution in which circulation takes place, whereby hydrogen and alkali water glass solution (with insoluble metals and / or other insoluble deposits contained therein) are produced simultaneously by direct conversion of the silicon, which are discharged from the reactor after the required reaction time and the alkali water glass solution is filtered in a filter and the undissolved metals and / or other undissolved deposits collect in the filter.

[0023] In variants B and C, the silicon dissolves and a water glass solution is formed.

[0024] In the process according to variant C for recycling silicon elements, particularly those made of crystalline silicon in the form of waste silicon elements with aluminum deposits, e.g., aluminum contacts, these are fed into a reactor containing an aqueous alkali hydroxide solution for hydrogen production. Hydrogen, alkali water glass solution, aluminosilicates, and / or zeolites, as well as heat, are simultaneously generated in the reactor through direct reaction with an aqueous alkali hydroxide solution and then removed from the reactor. The aluminum dissolves first.

[0025] Silicon with aluminum deposits reacts step by step with alkali hydroxide solution to form alkali aluminate solution, which can be isolated. It is also possible to continue the reaction, so that the aluminate reacts with silicon (alkali silicate) to form aluminosilicates.

[0026] Furthermore, it is possible to first remove the aluminum using alkaline and then integrate the silicon into the aforementioned variant A.

[0027] According to the processes of variants A, B, and C, heat is generated simultaneously, the heat released during the reaction is removed and made usable by means of a heat exchanger.

[0028] According to the invention, silicon elements, e.g., solar cells, whole or crushed, are reacted with water or alkali solution in a reactor. The first main product is either alkali water glass solution or silica. The second main product is always hydrogen. The hydrogen is extracted and dried, and can be used for conventional applications. After the reaction is complete, the reactor contents are filtered.

[0029] In the method according to the invention for recycling waste from silicon elements made of, in particular, crystalline silicon, in particular from silicon cell scrap, the waste is mixed with a diluted alkali hydroxide solution, in particular lithium, sodium or potassium hydroxide solutions, in particular in order to produce specific, commercially available water glass solutions / alkali water glass solutions therefrom.

[0030] The alkali oxide / silicon dioxide ratio of the desired end products should be transferred stoichiometrically exactly to the amounts or concentrations of the reactants.

[0031] The invention achieves a number of advantages: The disposal and processing costs incurred in the prior art are minimized, and instead different products can be manufactured from the described waste, preferably alkali water glass solutions, silver and / or copper, hydrogen and heat. During the process according to the invention, the generation of heat is also observed, which is also regarded as a product. This means that the energy previously used to produce silicon can largely be reused, on the one hand in the form of a new energy carrier, hydrogen, and on the other hand directly in the form of heat. The present invention now relates to a versatile method and a plant for the utilization of photovoltaic cell waste without adhesions or with metal-containing ormetallic or other silicon-based deposits, which follows a zero-waste concept and does not produce any significant residual materials as new waste.

[0032] Silicon cell scrap is often present with contacts; contact metals can be silver, silver-coated copper, or even just copper; furthermore, other deposits such as graphite or quartz can also be present.

[0033] In this case, alkali hydroxide solution must be used so that the remaining metals can be filtered out of the clear reaction product, the water glass solution.

[0034] Additional hydrogen is produced and heat is released.

[0035] If silicon wafer fracture is present without metallic adhesions, e.g. contacts, alkali hydroxide can be used: hydrogen, heat and the corresponding alkali water glass solutions are produced - but no metals are recovered in the filter, because they were not present.

[0036] Alternatively, you can also work with just water if you don't want an alkali silicate solution, but rather silica, which you separate in the filter. Here, too, you would generate hydrogen and heat in the process.

[0037] The silicon, which the cells or cell fragments mainly consist of, reacts completely with the respective alkali hydroxide or water.

[0038] In the case of alkali hydroxides, the corresponding alkali silicates or water glasses are formed. If water reacts alone, the silicon forms silicic acid, or SiO2.

[0039] The invention is explained in more detail below using an exemplary embodiment and associated figures, without being limited to these. It shows:

[0040] Figure 1 shows a schematic diagram of the device according to the invention. The device according to the invention comprises a reactor R in the form of an autoclave with the following components:

[0041] A top-mounted filler neck 1 for supplying cell fragments from solar cells. The filler neck also serves for adding the respective liquid reactant, here in the form of the alkali hydroxide solution or water. Alternatively, a separate filler neck (not shown) could be provided for this purpose.

[0042] A heat exchanger 2 which is arranged here, for example, in the middle and on the outer circumference of the autoclave.

[0043] An agitator or stirrer 3, inside the autoclave / reactor R.

[0044] A hydrogen outlet 4, preferably arranged at the top.

[0045] A gas dryer 5 for the removed hydrogen.

[0046] A compressor 6 downstream of the gas dryer 5.

[0047] A gas storage 7 downstream of the compressor 6 for storing the hydrogen.

[0048] A drain valve 8 for the alkali water glass solution or silica, depending on what was fed to the reactor (alkali hydroxide solution or water).

[0049] At least for variant B, a filter 9 arranged downstream of the drain valve for filtering the components that have not dissolved (preferably silver and / or copper and / or graphite and / or quartz) from the alkali water glass solution and with an outlet 10 for the filtered alkali water glass solution.

[0050] Preferably, all variants A to C should have a filter.

[0051] If the silicon waste intended for recycling contains metallic deposits such as silver and / or copper or other metals and / or graphite and / or quartz, it is introduced into the reactor R / autoclave using alkali hydroxide solution and the mixture is circulated, preferably stirred, in the reactor for a defined time (this can be determined through preliminary tests). As the silicon dissolves, hydrogen and metal-containing alkali water glass solution are produced, from which the metals are filtered after being discharged from the reactor.

[0052] If the silicon cells or silicon scrap do not exhibit any metallic deposits, water is used. Using only water produces hydrogen and silica, which are released from the reactor through the drain valve after the required reaction time.

[0053] In general, the aforementioned processes generate heat, which can be dissipated via a heat exchanger and supplied to a consumer.

[0054] If the silicon cell scrap contains aluminum deposits, the process is carried out as described below:

[0055] To dissolve aluminum contacts in silicon elements, a dilute aqueous alkali hydroxide solution (preferably 5 to 25%) is preferably used. This forms an alkali aluminate solution, which can be filtered off. The second step is variant B. This involves the pretreatment, the aluminum separation, so that, for example, the remaining silicon / silver mixture can be treated according to variant B. This is always recommended when silver and / or copper are present in addition to aluminum and silicon.

[0056] According to another process example described below, starting from currently common HJT silicon photovoltaic cells containing silver deposits, the cell fragments with a mass of 7.5 g were placed in an autoclave / reactor R after a comminution step and covered with 80 g of 13% NaOH (alkali hydroxide solution). The autoclave was sealed, and the reactants were mixed thoroughly using a magnetic stirrer with stirrer 3.

[0057] The autoclave was then heated using a heater (not shown). The internal temperature was monitored, and upon reaching 40°C, a rapid increase in temperature and pressure was observed. The reaction was complete after approximately 30 minutes. The exact reaction time can be determined by simple experiments. This is followed by a stirring period while maintaining the temperature at 135°C for a further, preferably 30 minutes. The stirring time required for the complete decomposition / dissolution of the silicon can also be determined by simple preliminary experiments.

[0058] The maximum values ​​for this experiment were determined at 236°C and 80 bar in the autoclave. The heating was turned off, and when the temperature reached 70°C, the pressure was reduced from 59 bar to atmospheric pressure. The escaping gas was collected and identified as 6.7 L of hydrogen. The drain valve 8 of the autoclave / reactor R was then opened, and the reactor contents were filtered. The clear, colorless waterglass solution had a density of 1.28 d / ml and was chemically characterized. Analysis revealed a SiO2 content of 3.81 mol and a Na2O content of 1.72 mol. This ratio, 2.2 to 1, corresponds to a commercially available waterglass solution (here, alkali waterglass solution).

[0059] The residue on the filter material of filter 9 was determined to be 0.11 g, which corresponds to 1.5% of the sample weight. This is silver.

[0060] Through a heat exchanger 2, which is arranged here, for example, in the middle and on the outer circumference of the autoclave / reactor R, the resulting process heat can be dissipated and used, for example, for heating purposes or any consumer or for another purpose.

[0061] The silicon elements, preferably made of crystalline silicon, from which the cells or cell fragments mainly consist, react completely with the respective alkali hydroxide or water.

[0062] In the case of alkali hydroxides, the corresponding alkali silicates or water glasses are formed. If water reacts alone, the silicon forms silicic acid, or SiO2.

[0063] In particular, crystalline silicon types (p- and / or n-conducting and / or amorphous) are processed, if necessary with metallic adhesions or contacts made of silver and / or silver alloys and / or silver-plated copper and / or copper, but also with aluminum.

[0064] The method and the device are also applicable for the treatment of, in particular, c-Si solar cells or other silicon-based cell types or microchips made of silicon or also for perovskites or perovskite solar cells.

[0065] The inventive solution for recycling solar cells provides a very simple and cost-effective process and device that is predestined for use as a large-scale solution.

[0066] In large-scale applications, the generation of pressure in the reactor can also be dispensed with.

Claims

AMENDED CLAIMS received by the International Bureau on 31 March 2025 (31.03.2025) 1. A process for recycling silicon elements, in particular made of crystalline silicon, characterized in that it is carried out in a reactor (R), in particular in the form of an autoclave, wherein the reactor has a filler neck (1) for supplying shredded waste (cell breakage) or non-shredded waste, a heat exchanger (2), an agitator or stirrer (3), a hydrogen outlet (4), a gas dryer (5), a compressor (6) downstream of the gas dryer (5), a gas reservoir (7) downstream of the compressor (6), a drain valve (8), a filter (9) downstream of the drain valve, in which insoluble metals and / or other insoluble deposits accumulate, and an outlet (10) for the filtered water glass solution, and wherein in a variant A: waste from silicon elements which have no metallic deposits,are introduced into the reactor (R) with water and circulated therein with the stirrer (3), and that hydrogen and silica are produced simultaneously by direct reaction of the silicon with water and the hydrogen is discharged from the reactor (R) via the drain valve (8) after the required reaction time, whereby in the event that cell fragments are processed without contact, the target product is not water glass but silica and hydrogen or in variant B: waste from silicon elements which contain insoluble (from description page 4, line 15) metals and / or adhesions, such as graphite or quartz, are introduced into the reactor (R) with alkali hydroxide solution and circulated therein with the stirrer (3),and that by direct reaction of the silicon, hydrogen and alkali water glass solution with the metals and / or adhesions contained therein are simultaneously produced and, after the required reaction time, are discharged from the reactor (R) via the discharge valve (8) and which, AMENDED SHEET (ARTICLE 19) Alkali water glass solution is filtered in a filter and the insoluble metals and / or other insoluble deposits accumulate in the filter or in a variant C: waste from silicon elements, which have deposits of aluminum, are introduced into the reactor (R) and in this silicon with aluminum are gradually mixed with alkali hydroxide solution to alkali aluminate solution, whereby the alkali aluminate solution is subsequently isolated or whereby the reaction is continued in the reactor and the Aluminate is allowed to react with the remaining silicon to form aluminosilicates and that hydrogen is discharged via the hydrogen outlet (4) and dried in the gas dryer (5), compressed in the compressor (6) and stored in the gas storage (7) and that in variants B. and C. the reactants, which are in the form of crushed or uncrushed waste from silicon elements, are reacted by heating the alkali hydroxide solution, preferably to 30°C to 80°C and that in variants A., B. and C. heat is generated at the same time and the heat released during the reaction is dissipated and made usable by means of a heat exchanger.

2. Method according to claim 1, characterized in that in the methods according to variants A., B. and C. the exact reaction time is determined by tests.

3. Process according to one of claims 1 to 2, characterized in that the hydrogen produced is led out of the reactor (R), dried and collected.

4. A method according to any one of claims 1 to 3, characterized in that in the case of waste from silicon elements according to the method of variant B., which have insoluble metals and / or insoluble adhesions, AMENDED SHEET (ARTICLE 19) 15 After the reaction has ended, the reactor contents are filtered and the silver or other metal remaining in the reactor (R) and the respective water glass solution are separated and used for further processing.

5. A process for recycling waste from silicon elements made in particular from crystalline silicon, in particular from silicon cell scrap, characterized in that the waste is mixed with a dilute alkali hydroxide solution, in particular lithium, sodium or potassium hydroxide solutions, and that alkali water glass solutions are obtained therefrom.

6. Process according to claim 5, characterized in that the alkali oxide / silicon dioxide ratio of the desired end products is transferred stoichiometrically exactly to the amounts or concentrations of the reactants.

7. Device for carrying out the method according to one of claims 1 to 6 for recycling silicon elements made of crystalline silicon in particular, characterized in that it has a reactor (R), in particular in the form of an autoclave, with the following components: a filler neck (1) for supplying shredded waste (cell breakage) or non-shredded waste, a heat exchanger (2), an agitator or stirrer (3), a hydrogen outlet (4), a gas dryer (5), a compressor (6) downstream of the gas dryer, a gas storage device (7) downstream of the compressor, a drain valve (8), a filter (9) downstream of the drain valve in which insoluble metals and / or other insoluble deposits collect and with an outlet (10) for the filtered water glass solution.

8. Device according to claim 7, characterized in that the filler neck (1) and the hydrogen outlet (4) are arranged in the upper region of the reactor (R) and the drain valve (8) is arranged in the lower region of the reactor (R). AMENDED SHEET (ARTICLE 19) 9. Device according to claim 7 or 8, characterized in that it has a heater for heating the substances in the reactor (R). AMENDED SHEET (ARTICLE 19) 2023-0096WO 31.03.2025 Changes after research report -10- Patent claims 1. A process for recycling silicon elements, in particular made of crystalline silicon, characterized in that it is carried out in a reactor (R), in particular in the form of an autoclave, wherein the reactor - a filling nozzle (1) for supplying shredded waste (cell breakage) or non-shredded waste, - a heat exchanger (2), - a stirrer or agitator (3), - a hydrogen outlet (4), - a gas drying system (5), - a compressor (6) downstream of the gas drying (5) - a gas storage device (7) connected downstream of the compressor (6), - a drain valve (8), - a filter (9) downstream of the drain valve in which insoluble metals and / or other insoluble deposits accumulate and 4 has an outlet (10) for the filtered water glass solution, and wherein in a variant A: waste from silicon elements, which have no metallic adhesions, are introduced into a reactor (R) with water and circulated therein with the stirrer (3), and that by direct reaction of the silicon with water, hydrogen and silica are simultaneously produced and the hydrogen is discharged from the reactor (R) via the discharge valve (8) after the required reaction time, wherein in the case of cell fragments being processed without contact, the target product is not water glass but silica and hydrogen, or in a variant B: waste from silicon elements, which have insoluble (from description page 4, line 15) metals and / or adhesions, such as graphite or quartz, are introduced into a reactor (R) with alkali hydroxide solution and circulated therein with the stirrer (3),and that by direct reaction of the silicon, hydrogen and alkali water glass solution with the metals and / or adhesions contained therein are simultaneously produced and, after the required reaction time, from the, 2023-0096WO 31.03.2025 Changes after research report -11- reactor (R) via the drain valve (8) and the alkali water glass solution is filtered in a filter and the insoluble metals and / or other insoluble deposits accumulate in the filter or Variant C: Waste from silicon elements, which has deposits of aluminum, is introduced into a reactor (R) and in this silicon reacts with aluminum step by step with alkali hydride solution alkali hydroxide solution (from description page 4 line 30) to form alkali aluminate solution, wherein the alkali aluminate solution is then isolated or wherein the reaction is continued in the reactor and the aluminate is allowed to react with the remaining silicon to form aluminosilicates and that hydrogen is discharged via the hydrogen outlet (4) and dried in the gas dryer (5), compressed in the compressor (6) and stored in the gas storage (7), and that in variants B. and C. the reactants, which are in the form of crushed or uncrushed waste from silicon elements, are reacted by heating the alkali hydroxide solution, preferably to 30°C to 80°C (from claim 4) and that in variants A., B. and C.at the same time heat is generated and the heat released during the reaction is removed and made usable by means of a heat exchanger (from claim 3).

2. A process according to claim 1, characterized in that in the process according to variants A, B and C, the exact reaction time is determined by experiments. — A process according to one of claims 1 or 2, characterized in that in variants A, B and C, heat is generated simultaneously and the heat released during the reaction is dissipated and utilized by means of a heat exchanger. 4-, — Process according to one of claims 1 to 3, characterized in that in the process according to variants B. or C. the reactants which are in the form 2023-0096WO 31.03.2025 Changes after research report -12- the crushed or uncrushed waste of silicon elements are reacted by heating the alkali hydride solution, preferably to 30°C to 80°C. 5r3. Process according to one of claims 1 to 42, characterized in that the hydrogen produced is led out of the reactor (R), dried and collected. ^4. A process according to any one of claims 1 to 35, characterized in that in the case of waste from silicon elements according to the process of variant B, which contain insoluble metals and / or insoluble deposits, the reactor contents are filtered after completion of the reaction and thus the silver or other metal remaining in the reactor (R) and the respective water glass solution are separated and passed on to further use. 7r5. A process for recycling waste from silicon elements, particularly from crystalline silicon, in particular from silicon cell scrap, characterized in that the waste is mixed with a dilute alkali hydroxide solution, particularly lithium, sodium or potassium hydroxide solutions, and that alkali water glass solutions are obtained therefrom. 8r6. Process according to claim 1, characterized in that the alkali oxide / silicon dioxide ratio of the desired end products is transferred stoichiometrically exactly to the amounts or concentrations of the reactants.

79. Apparatus for carrying out the method according to one of claims 1 to 6 for recycling silicon elements, in particular made of crystalline silicon, characterized in that it comprises a reactor (R), in particular in the form of an autoclave, with the following components: a filler neck (1) for supplying shredded waste (cell breakage) or non-shredded waste, a heat exchanger (2), an agitator or stirrer (3), a hydrogen outlet (4), a gas dryer (5), a compressor (6) connected downstream of the gas dryer 2023-0096WO 31.03.2025 Changes after research report -13- a gas reservoir (7) downstream of the compressor, a discharge valve (8), a filter (9) downstream of the discharge valve in which insoluble metals and / or other insoluble deposits accumulate and - with an outlet (10) for the filtered water glass solution.

840. Device according to claim 79, characterized in that the filler neck (1) and the hydrogen outlet (4) are arranged in the upper region of the reactor (R) and the drain valve (8) is arranged in the lower region of the reactor (R).

944. Device according to claim 79 or 849, characterized in that it has a heater for heating the substances in the reactor (R).

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