Equipment for preparing industrial silicon by decomposing serpentine
Through the two-stage countercurrent leaching reaction and solid-liquid separation device combined with reduction smelting, refining and impurity removal technology, the equipment gap of serpentine decomposition to prepare industrial silicon has been solved, efficient and low-cost industrial silicon production has been achieved, and the comprehensive utilization of serpentine resources has been promoted.
Patent Information
- Application Number
- CN202422834451.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-09-26
- Estimated Expiration
- 2034-11-19
AI Technical Summary
There is no equipment for preparing industrial silicon by decomposing serpentine in the prior art, resulting in low resource utilization efficiency.
A two-stage countercurrent leaching reaction device and a solid-liquid separation and washing device are used, combined with reduction smelting, refining and impurity removal processes to form a complete industrial silicon production line, including silicon slag drying, reduction smelting, refining and impurity removal steps, to achieve efficient decomposition of serpentine.
It has achieved industrial silicon production with a short growth process, less environmental pollution, less energy consumption and lower cost, and opened up new ideas for the comprehensive utilization of serpentine resources.
Smart Images
Figure CN223381132U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of preparing industrial silicon from serpentine, in particular to equipment for preparing industrial silicon by decomposing serpentine. Background Art
[0002] With the rapid development of modern industry, traditional metal resources are on the verge of depletion. Therefore, it is imperative to find and develop new metal resources.
[0003] my country is rich in serpentinite mineral resources, primarily ultramafic serpentinite deposits. These deposits are numerous, large, widely distributed, and possess excellent quality. Serpentine is a 1:1 phyllosilicate composed of silicon-oxygen tetrahedral sheets and magnesium-oxygen octahedral sheets. It primarily includes chrysotile, antigorite, and lizardite. Serpentinite, serpentine tailings, and asbestos tailings primarily consist of serpentine with minor amounts of magnetite, talc, brucite, dolomite, and calcite. The primary chemical composition is SiO₂ and MgO₂, with minor amounts of Fe₂O₃, Al₂O₃, NiO₂, and Cr₂O₃.
[0004] Currently, the most common method for serpentine resource utilization is to add organic and inorganic acids to the raw serpentine for direct acid leaching to produce magnesium-containing compounds. The residue after extracting magnesium oxide from serpentine is directly reacted with sodium hydroxide to produce chemical products such as sodium metasilicate and white carbon black. To date, no equipment has been developed to decompose serpentine to produce industrial silicon. Summary of the Invention
[0005] The technical problem to be solved by the utility model is to provide a device for preparing industrial silicon by decomposing serpentine.
[0006] The utility model is achieved in this way:
[0007] Disclosed is a device for preparing industrial silicon by decomposing serpentine. The system comprises a two-stage countercurrent leaching reaction device, the leachate outlet of the two-stage countercurrent leaching reaction device is connected to a solid-liquid separation and washing device, and the silicon slag outlet of the solid-liquid separation and washing device is connected to an industrial silicon production line; the industrial silicon production line comprises a silicon slag drying device, a reduction smelting device, and a refining and impurity removal device connected in sequence.
[0008] Furthermore, the fume outlet of the reduction smelting device is connected to a dust removal device.
[0009] Furthermore, the flue gas outlet of the reduction smelting device is connected to the dust removal device through a waste heat boiler.
[0010] Furthermore, the powder outlet of the dust removal device is connected to a dust density conveying device.
[0011] Furthermore, the silicon slag drying device includes a rotary kiln.
[0012] Furthermore, the refining and impurity removal device includes a metallic silicon furnace external refining oxygen blowing device.
[0013] The advantages of the utility model are that the system of the utility model has the characteristics of short growth process, small environmental pollution, low energy consumption, and low cost, and has opened up a new development idea for the comprehensive utilization of serpentine resources in my country. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0015] Figure 1 It is a structural diagram of the present utility model.
[0016] The numbers in the figure are: two-stage countercurrent leaching reaction device 1, solid-liquid separation and washing device 2, silicon slag drying device 3, reduction smelting device 4, refining and impurity removal device 5, and dust removal device 6. DETAILED DESCRIPTION
[0017] In the description of the present invention, it should be understood that the description indicating the orientation or position relationship is based on the orientation or position relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the scope of protection of the present invention.
[0018] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.
[0019] The technical solution of the utility model is as follows:
[0020] See also Figure 1 As shown, the present invention is a device for preparing industrial silicon by decomposing serpentine. The system includes a two-stage countercurrent leaching reaction device 1, the leachate outlet of the two-stage countercurrent leaching reaction device 1 is connected to a solid-liquid separation and washing device 2, and the silicon slag outlet of the solid-liquid separation and washing device 2 is connected to an industrial silicon production line; the industrial silicon production line includes a silicon slag drying device 3, a reduction smelting device 4, and a refining and impurity removal device 5 connected in sequence.
[0021] Furthermore, the flue gas outlet of the reduction smelting device is connected to a dust removal device 6 .
[0022] The specific process steps of the utility model are as follows:
[0023] 1. Slurry storage and filtration
[0024] Serpentine ore is transported to the smelting yard, where it undergoes coarse and fine crushing to a particle size of approximately 10mm. This ore is stored in the coarse powder silo of the grinding system before entering the grinding system. The coarse powder is fed into the vertical mill via a metering feeder, a belt conveyor, and a bucket elevator. Fine powder is collected by a baghouse dust collector and then hoisted via a pneumatic chute and bucket elevator to the fine powder silo for temporary storage. The fine powder particle size is controlled to be at least 0.074mm, with a minimum of 85%. The fine powder is then slurried in a slurry mixing tank on the top of the silo before being fed to the leaching unit.
[0025] 2. Hydrochloric acid leaching
[0026] A two-stage countercurrent leaching reaction device 1 is used to leach most of the magnesium into the leachate through two-stage countercurrent normal pressure hydrochloric acid leaching:
[0027] The pretreated raw material slurry first enters the primary leaching process. The primary leaching slurry temperature is controlled at approximately 80°C to 85°C, and the leaching time is 2 to 3 hours. Most metal oxides are leached in the primary leaching process. The overflow from the primary leaching process, which concentrates the material, is sent to the neutralization process for iron removal. The residual acid content is between 5 and 15 g / L. The primary leaching underflow is sent to the secondary leaching process. The secondary leaching slurry temperature is controlled at approximately 95 to 100°C, and the leaching time is 2 to 3 hours. The crude silica slag obtained after secondary leaching separation is sent to the CCD for washing; the overflow from the secondary leaching process is returned to the primary leaching process.
[0028] 3. CCD and silicon slag filtration
[0029] The crude silica slag from the leaching plant is slurried and then countercurrently washed in CCD thickener 2, using product wash water and tail gas scrubber liquid. To improve CCD scrubbing efficiency, the system utilizes a five-stage countercurrent scrubbing system with a controlled wash ratio of 2:1 (weight ratio of wash water to solids entering the thickener). The overflow from CCD1 is fed to the first leaching stage. The underflow from CCD5 is filtered, and the filtered, water-containing crude silica is conveyed by belt conveyor to the pyrometallurgical workshop for further silicon product production.
[0030] 3.1 Industrial silicon smelting process
[0031] 3.1.1 Silicon slag and auxiliary material composition
[0032] The raw materials for industrial silicon production include silica, carbonaceous reducing agents and electrodes.
[0033] Silicon slag source and composition:
[0034] After wet hydrochloric acid leaching, filtration and washing, high silicon slag is obtained, and the moisture content of the silicon slag is 25%.
[0035] 3.1.2 Industrial silicon smelting
[0036] Using silicon slag as the primary raw material, upgraded coke powder and wood blocks as reducing agents, the smelting process is carried out in a semi-enclosed electric furnace. The process consists of five stages: silicon slag drying, material preparation, smelting, refining, and finished product processing.
[0037] (1) Silicon slag drying
[0038] The silicon slag produced by the wet method has a high moisture content and cannot be directly used for electric furnace smelting. The utility model adopts a rotary kiln 3 to dry the silicon slag, and the fuel is natural gas. After drying, the moisture content of the silicon slag is less than 1%.
[0039] (2) Prepare materials
[0040] Purchased upgraded coke fines are unloaded from trucks into silos. To improve production efficiency and reduce energy consumption, the batching of the 8×33MVA industrial silicon furnace is designed to be fully automated. Dried silicon slag and upgraded coke fines are metered and mixed using a quantitative feeder with a controlled metering accuracy of 0.5%. The mixture is then compacted using a roller press to produce high-strength lumps. Feeding, weighing, and batching are automatically controlled by a DCS. The batched mixture is conveyed to the furnace's high-span platform by a steeply inclined loading conveyor. A distribution belt then unloads the mixture into the furnace's roof silo. Charge is intermittently added to the furnace through a feed pipe, ensuring continuous smelting and scheduled tapping. Each furnace is equipped with 12 overhead silos, each containing 12 feed pipes: one central feed pipe and three external feed pipes. To prevent eddy currents, the feed pipes and the portion below the short mesh of the electrode holder are constructed primarily of non-magnetic stainless steel. The lower portion of the feed pipe is water-cooled.
[0041] (3) Smelting
[0042] The mixed material is delivered to the electric furnace 4 through the top hopper and the discharge pipe for smelting. Smelting is continuous, with batch addition and intermittent silicon discharge. Depending on the smelting conditions of the electric furnace, the charge is added to the furnace 4 in batches. Current is passed through the electrodes, generating a high-temperature arc between the electrodes and the charge, heating and melting the charge and causing a reduction reaction. The electric furnace is equipped with five silicon outlets, which are used alternately. Liquid silicon is discharged from the furnace every 2-3 hours. When a certain amount of liquid silicon accumulates at the bottom of the furnace, the outlet is opened using a furnace eye opener or burn-through device, allowing the liquid silicon to flow directly into the silicon ladle on the ladle cart. Refining is performed inside the ladle using oxygen-enriched bottom blowing using synthetic slag from outside the furnace.
[0043] The flue gas from the electric furnace first passes through a waste heat boiler to recover waste heat, then passes through a dust removal system 6 to remove dust before being discharged. The flue gas from the electric furnace contains a large amount of highly volatile SiO2 gas. Upon discharge, the gas rapidly condenses upon cooling and undergoes a disproportionation reaction, producing Si and SiO2 powder, or microsilica fume. After being recovered by the dust removal system, the resulting material is encrypted and packaged using encryption equipment and stored in a microsilica fume warehouse. It can be sold as a by-product or returned to the batching system.
[0044] (4) Refining
[0045] An oxygen blowing device 5 is used for refining metallic silicon outside the furnace. The oxygen and compressed air delivered from the oxygen station and the air compressor station are input into the bottom of the silicon ladle and the diffused air bricks through a heat-resistant rubber tube to react with the silicon liquid just out of the furnace to remove the impurities Ca and Al. 2-3 minutes before the silicon is taken out of the furnace, compressed air is first introduced into the bottom of the ladle to prevent the silicon liquid from flowing into the air vents. When the silicon liquid reaches 1 / 3 of the bottom depth of the silicon ladle, oxygen can be turned on for oxidation refining. After the furnace is blocked and the refining is completed (the content of aluminum, calcium, etc. reaches below the required value), the oxygen can be turned off, and the silicon ladle is pulled from the furnace trolley to the casting span for secondary refining. After pouring the silicon liquid, compressed air is continued to be introduced for 3-5 minutes to prevent the diffused air holes from being blocked. The heat-resistant rubber tube can be removed later, and the silicon slag can be removed, waiting to be taken out of the furnace.
[0046] (5) Finished product processing
[0047] After the silicon liquid is blown, it is transported to the casting room, where the sediment is left to stand and samples are taken for testing, while the crane is used for casting.
[0048] 4. Products
[0049] Industrial silicon products generally have a particle size of 5 to 120 mm and are stored in bags in the finished product warehouse. Product quality complies with the chemical silicon standards in the "Industrial Silicon" (GB / T2881-2014) standard.
[0050] Although the specific implementation methods of the present invention are described above, those skilled in the art should understand that the specific embodiments described are merely illustrative and are not intended to limit the scope of the present invention. Equivalent modifications and changes made by those skilled in the art in accordance with the spirit of the present invention should be included within the scope of protection of the claims of the present invention.
Claims
1. An apparatus for preparing industrial silicon by decomposing serpentine, characterized in that: It comprises a two-stage countercurrent leaching reaction device, the leachate outlet of the two-stage countercurrent leaching reaction device is connected to a solid-liquid separation and washing device, and the silicon slag outlet of the solid-liquid separation and washing device is connected to an industrial silicon production line; The industrial silicon production line comprises a silicon slag drying device, a reduction smelting device, and a refining and impurity removal device which are connected in sequence.
2. The equipment for preparing industrial silicon by decomposing serpentine according to claim 1, characterized in that: The flue gas outlet of the reduction smelting device is connected to a dust removal device.
3. The equipment for preparing industrial silicon by decomposing serpentine according to claim 2, characterized in that: The flue gas outlet of the reduction smelting device is connected to the dust removal device through a waste heat boiler.
4. The equipment for preparing industrial silicon by decomposing serpentine according to claim 2, characterized in that: The powder outlet of the dust removal device is connected to the dust density conveying device.
5. The equipment for preparing industrial silicon by decomposing serpentine according to claim 1, characterized in that: The silicon slag drying device includes a rotary kiln.
6. The equipment for preparing industrial silicon by decomposing serpentine according to claim 1, characterized in that: The refining and impurity removal device includes a metallic silicon furnace external refining oxygen blowing device.