Flue gas treatment system and multi-product co-production system for carbon reduction of lithium ores

Abstract

This utility model discloses a flue gas treatment system and a multi-product co-production system for carbon-reduced lithium ore, solving the technical problems of high energy consumption, large amount of waste residue, and low resource utilization in traditional lithium ore processing. The flue gas treatment system includes: a first heat exchange device and a first gas-solid separation device for cooling, pre-dust removal, and gas-solid separation of the flue gas, outputting a first clean gas and a second dust; a first water quenching device for water quenching the primary solid composed of the first and second dust, outputting a first solid-liquid mixture; a first liquid-solid separation device for liquid-solid separation of the first solid-liquid mixture, outputting a first solution; a second heat exchange device and a second gas-solid separation device for cooling, pre-dust removal, and gas-solid separation of the first clean gas, outputting a second clean gas and a fourth dust; and a second water quenching device for water quenching the secondary solid composed of the third and fourth dust, outputting a third clean gas and a second solution.

Description

Technical Field

[0001] This utility model relates to the technical field of high-temperature smelting of ores, and more specifically, to a flue gas treatment system and a multi-product co-production system for carbon-reduced lithium ore. Background Technology

[0002] The traditional main process of lithium ore processing is to extract and utilize lithium from the minerals. This is generally done by high-temperature calcination to reconstruct the mineral structure, followed by acidification and calcination (such as spodumene), or by mixing the minerals with sulfates and calcining them at high temperatures (such as lepidolite) to generate water-soluble lithium sulfate from the lithium oxide in the minerals. Then, the minerals undergo wet processes such as slag removal, impurity removal, purification, and refining to finally obtain the product lithium carbonate or lithium hydroxide.

[0003] Traditional ore calcination and roasting utilizes large smelting furnaces that occupy vast areas. Typically, a single molten metal discharge port is installed, and the molten metal, after being discharged as a whole, needs to be cooled, crushed, and then fed into the hydrometallurgical process. Because the composition of the molten metal formed from all the minerals and additives is complex, feeding it all into the hydrometallurgical process not only results in a massive processing volume and high energy consumption but also generates a large amount of waste residue. Ultimately, this leads to low resource utilization of lithium ore and low economic benefits.

[0004] Because the valuable substances in minerals are used in a limited way, a large amount of resources become waste, with only a portion being utilized for low-value purposes. Taking the spodumene sulfate process for producing lithium carbonate as an example, producing one ton of lithium carbonate requires more than 8 tons of concentrate containing 5% lithium oxide (generating approximately 7 tons of waste), or more than 33 tons of ore with a grade (Li₂O content) of 1.25% (generating more than 25 tons of tailings). If the lepidolite sulfate process is used to produce lithium carbonate, producing one ton of lithium carbonate requires approximately 30 tons of concentrate containing 1.5% lithium oxide (generating approximately 40 tons of waste), and more than 100 tons of ore with a grade of 0.4% (generating more than 70 tons of tailings).

[0005] It is evident that traditional lithium ore processing primarily involves wet extraction of lithium resources, which is energy-intensive, generates large amounts of waste, and essentially fails to recover other resources. However, in addition to lithium, lithium ore also contains many alkali metals and non-metals, all of which are valuable mineral resources. Utility Model Content

[0006] To address the technical problems of high energy consumption, large amounts of waste residue, and low resource utilization in traditional lithium ore processing technologies, this utility model provides a smelting furnace and a molten metal treatment system, a flue gas treatment system, a multi-product co-production system, and a multi-product co-production method for carbon-reduced lithium ore. The technical solutions are as follows:

[0007] A smelting furnace includes a furnace body and a discharge assembly. The discharge assembly includes, from bottom to top, the following components arranged on the furnace body: a high-density molten metal discharge mechanism, including a lower discharge port on the furnace body; a medium-density molten metal discharge mechanism, including a middle discharge port on the furnace body; and a low-density molten metal discharge mechanism, including an upper discharge port on the furnace body.

[0008] This utility model's smelting furnace has three discharge ports, which can discharge molten liquid layers distributed at different elevations according to the stratification phenomenon of different density components in the molten liquid. This allows for appropriate separation of different mineral molten liquids, directly obtaining multiple products with high enrichment or relatively pure products, or significantly simplifying subsequent material purification processes, enabling the co-production of multiple products, and thus significantly improving the utilization rate of natural ore resources. In particular, the three discharge ports of the smelting furnace can be used as needed, that is, the appropriate number and position of discharge ports can be opened according to different molten liquid compositions and production requirements. It can be used for smelting lithium ore, as well as silicon ore, lithium salt plant waste residue, lithium ore beneficiation plant tailings, and lithium-containing waste residue from non-ferrous smelting, etc., and has extremely strong practicality.

[0009] As a further improvement to the aforementioned smelting furnace: the lower discharge port, middle discharge port, and upper discharge port are arranged circumferentially along the furnace body. Preferably, the included angle between the horizontal projections of the lower discharge port and the middle discharge port, and the included angle between the horizontal projections of the middle discharge port and the upper discharge port, is not less than 10°. This facilitates the arrangement and use of the relevant pipelines and valves of the drainage mechanism.

[0010] As a further improvement to the aforementioned smelting furnace, it also includes a heating assembly, a feeding assembly, and a gas guide pipe connected to the interior of the furnace body. Preferably, the heating assembly includes at least three heating electrodes arranged in a ring. The feeding assembly includes at least three feeding pipes, which are at least evenly distributed around the periphery of the heating mechanism. This facilitates uniform heating and uniform feeding.

[0011] As a further improvement to the aforementioned smelting furnace, the feeding pipe includes an upper inclined section and a lower vertical section. This facilitates the arrangement of feeding bins around the perimeter of the smelting furnace, avoiding obstruction from the heating components.

[0012] As a further improvement to the aforementioned smelting furnace, it also includes an actuator and a power mechanism. The rapping structure is located inside the furnace body and is used to break up the crust formed on the furnace charge. The power mechanism is located outside the furnace body and is used to drive the actuator (such as rapping or rotation). This allows the actuator to break up the crust formed on the furnace charge, preventing large-scale material collapses inside the furnace and thus avoiding furnace instability.

[0013] As a further improvement to the aforementioned smelting furnace: the furnace body has a cylindrical internal shape with a diameter D of 1–12 meters and an internal height H that is 0.8–1.5 times the diameter D. Preferably, the furnace body includes an outer carbon steel shell, an inner refractory brick lining, and water-cooled coils. Compared with traditional smelting furnaces, most of which have a diameter of 8 meters or more, the smelting furnace of this invention can be miniaturized (D = 1–3 m, H = 0.8–3 m), and can be integrated with skid-mounted equipment to move it to work conditions requiring the smelting of small quantities of ore (such as lithium plant or non-ferrous metal plant waste slag, tailings, etc.), making it more convenient to use.

[0014] A molten lithium ore reduction system is provided, wherein carbon, lithium ore, and slagging agent undergo a reduction reaction in the aforementioned smelting furnace to generate molten liquid. The molten liquid treatment system includes: a first cooling device for cooling the high-density molten liquid output from the smelting furnace, outputting a first solid containing a manganese-iron-silicon alloy; a second cooling device for cooling the medium-density molten liquid output from the smelting furnace, outputting a second solid containing elemental silicon; and a third cooling device for cooling the low-density molten liquid output from the smelting furnace, outputting a third solid containing silicon dioxide and metal oxides.

[0015] Traditional molten lithium processing involves discharging the entire molten lithium, followed by cooling and crushing before proceeding to subsequent processes such as hydrometallurgical processes. This results in low resource utilization of lithium ore. In this novel molten lithium processing system, combined with the aforementioned smelting furnace with three discharge ports, and based on the high density (4 g / cm³) manganese-iron-silicon alloy... 3 The above), elemental silicon (medium density, approximately 2.3–2.4 g / cm³). 3 ) and scum (low density, approximately 2.1–2.2 g / cm³) 3 The stratification phenomenon in the melt (mainly due to the density difference of silicon dioxide and metal oxides) enables the independent recovery and co-production of the three melt components.

[0016] In actual production, the theoretical values ​​of the height / volume of each molten layer in the smelting furnace are calculated based on the raw material quality and reaction conditions. Then, based on the economic value of each molten layer, layers with heights higher or lower than the theoretical values ​​are discharged. For example, for the molten material generated by the reduction reaction of carbon, lithium ore, and slagging agents at high temperatures, if the expected product is elemental silicon, 5-10% of the theoretically high-density molten material can be allowed to flow into the third cooling device along with the low-density molten material. Then, 80-90% of the theoretically high-density molten material can flow into the second cooling device. Finally, 5-10% of the theoretically high-density molten material can flow into the first cooling device along with the high-density molten material. In this way, the material flowing into the second cooling device is relatively pure elemental silicon, thus directly obtaining a relatively pure elemental silicon product.

[0017] A flue gas treatment system for carbon-reduced lithium ore, wherein carbon and lithium ore undergo a reduction reaction in the aforementioned smelting furnace to generate flue gas; the flue gas treatment system includes: a first heat exchanger for cooling and pre-dust removal of the flue gas, outputting a first gas-solid mixture and a first dust; a first gas-solid separation device for gas-solid separation of the first gas-solid mixture, outputting a first clean gas and a second dust; a first water quenching device for water quenching the primary solid composed of the first and second dusts, outputting a first solid-liquid mixture; a first liquid-solid separation device for liquid-solid separation of the first solid-liquid mixture, outputting an insoluble slag and a first solution containing lithium hydroxide; a second heat exchanger for cooling and pre-dust removal of the first clean gas, outputting a second gas-solid mixture and a third dust; a second gas-solid separation device for gas-solid separation of the second gas-solid mixture, outputting a second clean gas containing carbon monoxide and a fourth dust; and a second water quenching device for water quenching the secondary solid composed of the third and fourth dusts, outputting a third clean gas containing acetylene and a second solution containing lithium hydroxide.

[0018] Traditional flue gas treatment processes involve cooling, dust removal, purification, and emission, without recovering or utilizing the resources within the flue gas. In this novel flue gas treatment system, the resulting insoluble slag can be returned to the smelting furnace for further refining. The resulting first and second solutions can be used to produce lithium hydroxide and potassium hydroxide. Because the smelting furnace operates under positive pressure, external air does not enter, resulting in a second clean gas primarily composed of carbon monoxide, which can be used as high-quality coal gas. The third clean gas is mainly acetylene. Furthermore, the equipment used has low investment and operating costs, is easy to operate and control, and ultimately achieves the co-production of multiple products. This allows for the efficient recovery of valuable resources from the flue gas, improving economic benefits and demonstrating strong practicality.

[0019] As a further improvement to the aforementioned flue gas treatment system, a first separation device is also included. This device separates the first solution, outputting an alkaline solution and solid lithium hydroxide. The separation of lithium hydroxide and potassium hydroxide can be achieved based on their solubility differences, simplifying operation and generating higher economic benefits.

[0020] As a further improvement to the above-mentioned flue gas treatment system, it also includes: a first evaporation crystallization device for evaporating and crystallizing the alkaline solution to output a first crystal dispersion; a second liquid-solid separation device for separating the first crystal dispersion to output solid alkali and recycled water; and a first drying device for drying the solid alkali to obtain the alkali product.

[0021] As a further improvement to the above-mentioned flue gas treatment system, it also includes: a second evaporation crystallization device for evaporating and crystallizing the second solution to output a second crystal dispersion; a third liquid-solid separation device for separating the second crystal dispersion to output lithium hydroxide solid and recycled water; and a second drying device for drying the lithium hydroxide solid to obtain lithium hydroxide product.

[0022] As a further improvement to the aforementioned flue gas treatment system, a third drying and granulation device is also included to sequentially dry and granulate the insoluble slag. Therefore, granulating the insoluble slag before refeeding it into the smelting furnace can improve the conversion rate without affecting the reactivity of the raw materials.

[0023] As a further improvement to the above-mentioned flue gas treatment system, it also includes a first powder tank for storing primary solids, a second powder tank for storing secondary solids, a first gas tank for storing secondary clean gas, and a second gas tank for storing tertiary clean gas.

[0024] As a further improvement to the above-mentioned flue gas treatment system: the first heat exchanger and the first gas-solid separation device constitute an integrated first heat exchange dust removal device; and / or, the second heat exchanger and the second gas-solid separation device constitute an integrated second heat exchange dust removal device.

[0025] A multi-product co-production system for carbon-reduced lithium ore includes a smelting furnace that reduces carbon, lithium ore, and slag-forming agents to produce flue gas and molten metal; the multi-product co-production system also includes a flue gas treatment system for treating the flue gas and / or a molten metal treatment system for treating the molten metal.

[0026] The flue gas treatment system comprises: a first heat exchanger for cooling and pre-dust removal of the flue gas, outputting a first gas-solid mixture and first dust; a first gas-solid separation device for gas-solid separation of the first gas-solid mixture, outputting a first clean gas and second dust; a first water quenching device for water quenching of the primary solid composed of the first dust and the second dust, outputting a first solid-liquid mixture; a first liquid-solid separation device for liquid-solid separation of the first solid-liquid mixture, outputting an insoluble slag and a first solution containing lithium hydroxide; a second heat exchanger for cooling and pre-dust removal of the first clean gas, outputting a second gas-solid mixture and a third dust; a second gas-solid separation device for gas-solid separation of the second gas-solid mixture, outputting a second clean gas containing carbon monoxide and a fourth dust; and a second water quenching device for water quenching of the secondary solid composed of the third dust and the fourth dust, outputting a third clean gas containing acetylene and a second solution containing lithium hydroxide.

[0027] The molten metal processing system includes: a first cooling device for cooling the high-density molten metal output from the smelting furnace to output a first solid containing a manganese-iron-silicon alloy; a second cooling device for cooling the medium-density molten metal output from the smelting furnace to output a second solid containing elemental silicon; and a third cooling device for cooling the low-density molten metal output from the smelting furnace to output a third solid containing silicon dioxide and metal oxides.

[0028] As a further improvement to the aforementioned multi-product co-production system: the smelting furnace includes a furnace body and a discharge assembly. The discharge assembly includes, from bottom to top, the following components arranged on the furnace body: a high-density molten liquid discharge mechanism, including a lower discharge port on the furnace body; the lower discharge port is connected to a first cooling device; a medium-density molten liquid discharge mechanism, including a middle discharge port on the furnace body; the middle discharge port is connected to a second cooling device; and a low-density molten liquid discharge mechanism, including an upper discharge port on the furnace body; the upper discharge port is connected to a third cooling device.

[0029] A multi-product co-production method for carbon-reduced lithium ore includes a reduction reaction of carbon, lithium ore, and slag-forming agent to generate flue gas and molten liquid; it also includes the treatment of flue gas and / or the treatment of molten liquid;

[0030] The steps for treating the flue gas include: reducing the flue gas temperature to 500–700°C and collecting the solids to obtain primary solids and a first clean gas; further reducing the temperature of the first clean gas to below 50°C and collecting the solids to obtain secondary solids and a second clean gas containing carbon monoxide; subjecting the primary solids to water quenching, and then filtering the resulting first solid-liquid mixture to obtain a first solution containing lithium hydroxide and an insoluble residue; subjecting the secondary solids to water quenching to obtain a third clean gas containing acetylene and a second solution containing lithium hydroxide.

[0031] The steps for processing the molten liquid include: separating the high-density molten liquid, medium-density molten liquid, and low-density molten liquid into sections according to the stratification of different density components in the molten liquid; cooling the high-density molten liquid to obtain a first solid containing manganese-iron-silicon alloy; cooling the medium-density molten liquid to obtain a second solid containing elemental silicon; and cooling the low-density molten liquid to obtain a third solid containing silicon dioxide and metal oxides.

[0032] As a further improvement to the above-mentioned multi-product co-production method, it also includes separating the first solution to obtain an alkaline solution and lithium hydroxide solid.

[0033] As a further improvement to the above-mentioned multi-product co-production method, the separation process includes the following steps: evaporating and concentrating the first solution to a supersaturated state, then cooling it to room temperature, adding anhydrous ethanol to precipitate lithium hydroxide, and then filtering to obtain an alkaline solution and solid lithium hydroxide.

[0034] As a further improvement to the above-mentioned multi-product co-production method, it also includes evaporation and crystallization treatment, filtration treatment and drying treatment of alkaline solution to obtain alkaline products and recycled water.

[0035] As a further improvement to the above-mentioned multi-product co-production method, it also includes evaporating and crystallizing the second solution, filtering and drying it to obtain lithium hydroxide product and recycled water.

[0036] As a further improvement to the above-mentioned multi-product co-production method, it also includes sequentially drying and granulating the insoluble residue.

[0037] As a further improvement to the aforementioned multi-product co-production method, the slag-forming agent is a CaO-SiO2-CaF2 composite slag-forming agent. This enriches silicon dioxide and various metal oxides on the surface of the molten liquid, increasing the purity of elemental silicon and facilitating the segmented discharge of the molten liquid.

[0038] The advantages of the multi-product co-production system and method for carbon-reduced lithium ore of this invention are the combination of the above-mentioned smelting furnace, melt treatment system and flue gas treatment system, which will not be elaborated here.

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Additional aspects and advantages of the present invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the present invention. Attached Figure Description

[0040] The accompanying drawings, which form part of this utility model, are used to aid in understanding this utility model. The content provided in the drawings and the related descriptions in this utility model can be used to explain this utility model, but do not constitute an undue limitation of this utility model. In the drawings:

[0041] Figure 1 This is a side view of the smelting furnace of this utility model.

[0042] Figure 2 This is a top view schematic diagram of the smelting furnace of this utility model.

[0043] Figure 3 This is a schematic diagram of the molten lithium ore treatment system, flue gas treatment system, and multi-product co-production system of the present invention.

[0044] The relevant markings in the above figures are:

[0045] 110 - Furnace body, 121 - Lower discharge port, 122 - Middle discharge port, 123 - Upper discharge port, 130 - Heating electrode, 140 - Feed pipe, 150 - Gas guide pipe, 160 - Power mechanism, 210 - First cooling device, 220 - Second cooling device, 230 - Third cooling device, 311 - First heat exchange device, 312 - First gas-solid separation device, 313 - First water quenching device, 314 - First liquid-solid separation device, 315 - First separation device, 31 6-First evaporation and crystallization equipment, 317-Second liquid-solid separation equipment, 318-First drying equipment, 321-Second heat exchange equipment, 322-Second gas-solid separation equipment, 323-Second water quenching equipment, 325-Second evaporation and crystallization equipment, 326-Third liquid-solid separation equipment, 327-Second drying equipment, 331-Third drying equipment, 332-Granulation equipment, 341-First powder tank, 342-Second powder tank, 343-First gas tank, 344-Second gas tank. Detailed Implementation

[0046] The present invention will now be clearly and completely described in conjunction with the accompanying drawings. Those skilled in the art will be able to implement the present invention based on these descriptions. Before describing the present invention in conjunction with the accompanying drawings, it should be particularly noted that:

[0047] The technical solutions and features provided in the various parts of this utility model, including the following description, can be combined with each other without conflict.

[0048] Furthermore, the embodiments of the present invention described below are generally only a part of the embodiments of the present invention, and not all of the embodiments. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the protection scope of the present invention.

[0049] Regarding the terminology and units used in this utility model: The terms "comprising," "having," and any variations thereof in the specification, claims, and related parts of this utility model are intended to cover non-exclusive inclusion.

[0050] Lithium mica is a lithium-containing layered silicate mineral, belonging to the mica group of minerals. Its general chemical formula can be roughly represented as K(Li,Al)3(Si,Al)4O 10 (F,OH)3, by mass fraction of oxides, mainly consists of silicon (approximately 54.7%), aluminum (approximately 25.7%), potassium (approximately 6.5%), fluorine (approximately 4.5%), lithium (approximately 3.5%), sodium (approximately 2.7%), and other metallic elements in very low amounts such as calcium, magnesium, manganese, iron, rubidium, and cesium.

[0051] Spodumene is a lithium-containing chain silicate mineral with a relatively stable composition. Its general chemical formula is LiAlSi2O6. By mass fraction of oxides, the main elements are silicon (about 64.5%), aluminum (about 26.5%), lithium (about 5.6%), sodium (about 1.17%), potassium (about 1%), and other metal elements with very low content such as calcium, magnesium, manganese, and iron.

[0052] Lithium mica and spodumene react with carbon powder in a smelting furnace at 1300-1900℃. In addition to decomposing into oxides of various elements, the following reactions also occur: (1) silicon dioxide reacts with carbon to produce silicon and carbon monoxide; (2) alloying reaction of manganese, iron and silicon; (3) alkali metal oxides react with carbon to produce alkali metal and carbon monoxide.

[0053] The resulting flue gas mainly contains unreacted raw material dust (such as mineral powder and carbon powder), unreacted oxide powder, alkali metal elements, and carbon monoxide. In particular, as the flue gas temperature decreases to 500–700°C, the carbon powder in the flue gas reacts with elemental lithium to form gaseous lithium carbide (i.e., lithium acetylene).

[0054] The resulting melt mainly consists of elemental silicon, various reactive oxides, and a manganese-iron-silicon alloy. The stratification at this stage is complex, making it difficult to discharge the melt in sections. To obtain a purer silicon melt, this invention employs a slag-forming process, enriching most of the silicon dioxide and metal oxides as scum on the surface of the melt. The resulting melt consists of a low-density upper layer primarily composed of scum of silicon dioxide and various metal oxides, a middle layer mainly composed of elemental silicon, and a lower layer mainly composed of manganese-iron-silicon alloy. The slag-forming process used in this invention involves adding a CaO-SiO2-CaF2 composite slag-forming agent to the raw materials. The dosage of the slag-forming agent is sufficient to maintain the pH of the melt at a weakly alkaline or near-neutral level (binary basicity R = 0.8–1.2, where R represents the mass ratio of CaO to SiO2 in the melt). Undecomposed silicon dioxide and metal oxides can be effectively enriched in the scum.

[0055] Regarding the molten metal and flue gas generated from the reduction reaction of carbon, lithium ore, and slagging agent in a smelting furnace at 1300–1900°C, the specific implementation methods of the smelting furnace, the molten metal treatment system for carbon-reduced lithium ore, the flue gas treatment system, the multi-product co-production system, and the multi-product co-production method provided by this utility model are as follows:

[0056] Figure 1 This is a side view of the smelting furnace of this utility model. Figure 2 This is a top view schematic diagram of the smelting furnace of this utility model.

[0057] like Figure 1-2The smelting furnace shown includes a furnace body 110 and a discharge assembly, a heating assembly, a feeding assembly, a gas guide pipe 150, an actuator (not shown in the figure), and a power mechanism 160 connected to the furnace body 110.

[0058] The discharge assembly includes, from bottom to top, a high-density molten metal discharge mechanism, a medium-density molten metal discharge mechanism, and a low-density molten metal discharge mechanism, along with corresponding pipes and valves, all arranged on the furnace body 110. The high-density molten metal discharge mechanism includes a lower discharge port 121 on the furnace body 110. The medium-density molten metal discharge mechanism includes a middle discharge port 122 on the furnace body 110. The low-density molten metal discharge mechanism includes an upper discharge port 123 on the furnace body 110. The heights of the lower discharge port 121, middle discharge port 122, and upper discharge port 123 are determined based on the actual composition of the molten metal produced during production.

[0059] The lower discharge port 121, the middle discharge port 122 and the upper discharge port 123 are arranged around the furnace body 110. The horizontal projection angle θ1 between the lower discharge port 121 and the middle discharge port 122 and the horizontal projection angle θ2 between the middle discharge port 122 and the upper discharge port 123 are both not less than 10°.

[0060] The heating assembly includes three heating electrodes 130 arranged in a ring; the feeding assembly includes seven feeding pipes 140, of which six feeding pipes 140 are evenly distributed around the heating mechanism and one feeding pipe 140 is located at the center of the heating mechanism; the feeding pipe 140 includes an upper inclined pipe section and a lower vertical pipe section.

[0061] The rapping structure is located inside the furnace body 110 and is used to break up the crust of the furnace charge. The power mechanism 160 is located outside the furnace body 110 and is used to drive the actuator to move.

[0062] The furnace body 110 has a cylindrical internal shape with a diameter D of 1 to 12 meters and an internal height H of 0.8 to 1.5 times the diameter D. The furnace body 110 includes an outer carbon steel shell, an inner refractory brick lining, and a water cooling coil.

[0063] Figure 3 This is a schematic diagram of the molten lithium ore treatment system, flue gas treatment system, and multi-product co-production system of the present invention.

[0064] like Figure 3 As shown, the melt processing system includes a first cooling device 210, a second cooling device 220, and a third cooling device 230.

[0065] The first cooling device 210 is used to cool the high-density molten liquid output from the smelting furnace, outputting a first solid containing a manganese-iron-silicon alloy; the lower discharge port 121 is connected to the first cooling device 210. The second cooling device 220 is used to cool the medium-density molten liquid output from the smelting furnace, outputting a second solid containing elemental silicon; the middle discharge port 122 is connected to the second cooling device 220. The third cooling device 230 is used to cool the low-density molten liquid output from the smelting furnace, outputting a third solid containing silicon dioxide and metal oxides; the upper discharge port 123 is connected to the third cooling device 230.

[0066] The flue gas treatment system includes a first heat exchanger 311, a first gas-solid separation device 312, a first water quenching device 313, a first liquid-solid separation device 314, a second heat exchanger 321, a second gas-solid separation device 322, a second water quenching device 323, a first separation device 315, a first evaporation crystallization device 316, a second liquid-solid separation device 317, a first drying device 318, a second evaporation crystallization device 325, a third liquid-solid separation device 326, a second drying device 327, a third drying device 331, and a granulation device 332.

[0067] The first heat exchanger 311 is used to cool and pre-remove dust from the flue gas, and outputs a first gas-solid mixture and a first dust. The first gas-solid separation device 312 is used to perform gas-solid separation on the first gas-solid mixture, and outputs a first clean gas and a second dust. The first water quenching device 313 is used to perform water quenching on the primary solid composed of the first dust and the second dust, and outputs a first solid-liquid mixture. The first liquid-solid separation device 314 is used to perform liquid-solid separation on the first solid-liquid mixture, and outputs an insoluble residue and a first solution containing lithium hydroxide.

[0068] The second heat exchanger 321 is used to cool and pre-remove the first clean gas, and outputs a second gas-solid mixture and a third dust. The second gas-solid separation device 322 is used to perform gas-solid separation on the second gas-solid mixture, and outputs a second clean gas containing carbon monoxide and a fourth dust. The second water quenching device 323 is used to perform water quenching on the secondary solid composed of the third dust and the fourth dust, and outputs a third clean gas containing acetylene and a second solution containing lithium hydroxide.

[0069] The first separation device 315 separates the first solution and outputs an alkaline solution and lithium hydroxide solid.

[0070] The first evaporation crystallization device 316 is used to evaporate and crystallize the alkaline solution to output a first crystal dispersion; the second liquid-solid separation device 317 is used to perform liquid-solid separation on the first crystal dispersion to output solid alkali and recycled water; the first drying device 318 is used to dry the solid alkali to obtain the alkali product.

[0071] The second evaporation crystallization device 325 is used to evaporate and crystallize the second solution to output a second crystal dispersion; the third liquid-solid separation device 326 is used to perform liquid-solid separation on the second crystal dispersion to output lithium hydroxide solid and recycled water; the second drying device 327 is used to dry the lithium hydroxide solid (from the first separation device 315 and the third liquid-solid separation device 326) to obtain lithium hydroxide product.

[0072] The third drying device 331 is used to dry the insoluble residue, and the granulation device 332 is used to granulate the dried insoluble residue and the third solid.

[0073] It also includes a first powder tank 341 for storing primary solids, a second powder tank 342 for storing secondary solids, a first gas tank 343 for storing secondary clean gas, and a second gas tank 344 for storing tertiary clean gas.

[0074] Preferably, the first heat exchange device 311 and the first gas-solid separation device 312 constitute an integrated first heat exchange dust removal device, and the second heat exchange device 321 and the second gas-solid separation device 322 constitute an integrated second heat exchange dust removal device. Specifically, the heat exchange dust removal device disclosed in application number 2021101312443 and patent titled "Heat Exchange Dust Removal Structure, Heat Exchange Dust Removal Device and High Temperature Dust-laden Gas Treatment Method" can be adopted.

[0075] The multi-product co-production system for carbon-reduced lithium ore includes the aforementioned melt processing system and flue gas treatment system.

[0076] The multi-product co-production method for carbon-reduced lithium ore of the present invention includes the treatment of flue gas and the treatment of molten metal. Wherein:

[0077] The steps for treating flue gas include steps 11-14, as follows:

[0078] Step 11: Reduce the flue gas temperature to 500-700℃ and collect the solids to obtain primary solids and primary clean gas. In this operation, during the process of the flue gas staying in the first heat exchanger 311, carbon powder reacts with elemental lithium to generate gaseous lithium carbide, while unreacted elemental lithium and other alkali metal elements such as sodium and potassium condense and adhere to the dust. They are collected in the primary solids through natural settling in the first heat exchanger 311 and physical interception in the first gas-solid separation device 312. The resulting primary clean gas mainly contains carbon monoxide and lithium carbide.

[0079] Step 12: Continue to lower the temperature of the first clean gas to below 50°C and collect the solid to obtain a secondary solid and a second clean gas containing carbon monoxide. In this operation, gaseous lithium carbide will condense and precipitate and be collected in the secondary solid by natural sedimentation of the second heat exchange device 321 and physical interception of the second gas-solid separation device 322. The resulting second clean gas mainly contains carbon monoxide.

[0080] Step 13: The first-stage solid is quenched using the first water quenching device 313, and then the resulting first solid-liquid mixture is filtered to obtain a first solution containing lithium hydroxide and an insoluble residue. In this operation, the alkali metal reacts with water to generate an alkaline first solution, while insoluble substances such as mineral powder and carbon powder are collected in the insoluble residue.

[0081] The first solution is separated using the first separation device 315 to obtain an alkaline solution and solid lithium hydroxide. Specifically, the first solution is evaporated and concentrated to a supersaturated state, then cooled to room temperature, and anhydrous ethanol is added to precipitate lithium hydroxide. The solution is then filtered to obtain the alkaline solution and solid lithium hydroxide. In this operation, lithium hydroxide precipitates due to its low solubility in anhydrous ethanol, and filtration yields relatively pure solid lithium hydroxide. Sodium hydroxide and potassium hydroxide remain dissolved in the liquid phase, thus yielding the alkaline solution.

[0082] The alkaline solution is further subjected to evaporation and crystallization, filtration and drying to obtain the alkaline product and recycled water.

[0083] Step 14: The secondary solid is quenched using the second water quenching device 323 to obtain a third clean gas containing acetylene and a second solution containing lithium hydroxide. In this operation, lithium carbide in the secondary solid reacts with water to generate lithium hydroxide and acetylene. The resulting second solution is a relatively pure lithium hydroxide solution, and the third clean gas mainly contains acetylene.

[0084] The second solution is further subjected to evaporation and crystallization, filtration and drying to obtain lithium hydroxide product and recycled water.

[0085] The steps for treating the molten liquid include steps 21-24, as follows:

[0086] Step 21: Based on the stratification of different density components in the melt, the high-density melt, medium-density melt, and low-density melt are discharged in sections.

[0087] Step 22: The high-density melt is cooled using the first cooling device 210 to obtain a first solid containing manganese-iron-silicon alloy, which can be further purified to obtain the manganese-iron-silicon alloy product.

[0088] Step 23: The medium-density melt is cooled using a second cooling device 220 to obtain a second solid containing elemental silicon, which can be further purified to obtain an elemental silicon product.

[0089] Step 24 involves cooling the low-density melt using a third cooling device 230 to obtain a third solid containing silicon dioxide and metal oxides. The third solid and the dried insoluble slag can be granulated simultaneously for processing in other stages.

[0090] The foregoing has described the relevant content of this utility model. Those skilled in the art will be able to implement this utility model based on these descriptions. All other embodiments obtained by those skilled in the art based on the above description of this utility model without inventive effort should fall within the protection scope of this utility model.

Claims

1. A flue gas treatment system for carbon reduction of lithium ore, wherein carbon and lithium ore undergo a reduction reaction in a smelting furnace to generate flue gas, characterized in that: The flue gas treatment system includes: The first heat exchange device (311) is used to cool and pre-remove the flue gas, and outputs a first gas-solid mixture and a first dust. The first gas-solid separation device (312) is used to perform gas-solid separation treatment on the first gas-solid mixture and output the first clean gas and the second dust. The first water quenching device (313) is used to perform water quenching treatment on the first-level solid composed of the first dust and the second dust, and output the first solid-liquid mixture. The first liquid-solid separation device (314) is used to perform liquid-solid separation treatment on the first solid-liquid mixture and output insoluble residue and a first solution containing lithium hydroxide; The second heat exchanger (321) is used to cool and pre-remove the first clean gas and output the second gas-solid mixture and the third dust. The second gas-solid separation device (322) is used to perform gas-solid separation treatment on the second gas-solid mixture and output a second clean gas containing carbon monoxide and a fourth dust. The second water quenching device (323) is used to perform water quenching treatment on the secondary solid composed of the third dust and the fourth dust, and outputs a third clean gas containing acetylene and a second solution containing lithium hydroxide.

2. The flue gas treatment system as described in claim 1, characterized in that: It also includes a first separation device (315), which separates the first solution and outputs an alkaline solution and lithium hydroxide solid.

3. The flue gas treatment system as described in claim 2, characterized in that: Also includes: The first evaporation crystallization device (316) is used to evaporate and crystallize the alkaline solution to output the first crystal dispersion. The second liquid-solid separation device (317) is used to perform liquid-solid separation treatment on the first crystal dispersion, and output solid alkali and recycled water; The first drying equipment (318) is used to dry solid alkali to obtain alkali products.

4. The flue gas treatment system as described in claim 2, characterized in that: Also includes: The second evaporation crystallization device (325) is used to perform evaporation crystallization on the second solution and output the second crystal dispersion. The third liquid-solid separation device (326) is used to perform liquid-solid separation treatment on the second crystal dispersion to output lithium hydroxide solid and recycled water; The second drying equipment (327) is used to dry the lithium hydroxide solid to obtain the lithium hydroxide product.

5. The flue gas treatment system as described in claim 1, characterized in that: It also includes a third drying device (331) and a granulation device (332) that sequentially dry and granulate the insoluble slag.

6. The flue gas treatment system as described in claim 1, characterized in that: It also includes a first powder tank (341) for storing primary solids, a second powder tank (342) for storing secondary solids, a first gas tank (343) for storing secondary clean gas, and a second gas tank (344) for storing tertiary clean gas.

7. The flue gas treatment system as described in claim 1, characterized in that: The first heat exchange device (311) and the first gas-solid separation device (312) constitute an integrated first heat exchange dust removal device; and / or, the second heat exchange device (321) and the second gas-solid separation device (322) constitute an integrated second heat exchange dust removal device.

8. A multi-product co-production system for carbon-reduced lithium ore, characterized in that: The flue gas treatment system for carbon-reduced lithium ore as described in any one of claims 1-7.

Images