Magnesium slag refining device

Abstract

The invention relates to the technical field of magnesium slag treatment equipment, and provides a magnesium slag refining device which comprises a pretreatment unit, a mixed reaction unit, a heating separation unit, a collection unit and a control system. The pretreatment unit comprises a first-stage crushing device, a buffer bin, a second-stage crushing device and a transmission device which are connected in sequence; a screening mechanism is arranged at the bottom of the primary crushing device. A first outlet is formed in an outlet of the primary smashing device, and a second outlet is formed in the tail end of the conveying device. The mixing reaction unit comprises a reaction tank, and a first mixing part and a second mixing part which are arranged up and down in the reaction tank. The heating separation unit is sequentially provided with a preheating zone, a reaction zone and a separation zone. And the collecting unit comprises a liquid collecting tank arranged at a liquid outlet of the separation area and a collecting tank arranged at a material outlet of the separation area. The magnesium slag crushing and grading precision can be improved, the mixing reaction sufficiency is improved, and then the valuable metal separation and purification effect is improved.

Description

Technical Field

[0001] This invention relates to the field of magnesium slag treatment equipment technology, and in particular to a magnesium slag refining device. Background Technology

[0002] Magnesium slag produced in the magnesium metallurgical industry contains a variety of valuable metals such as magnesium, aluminum, and calcium. If it is discarded directly, it will not only waste resources, but also pollute the soil and water sources due to the strong alkalinity of magnesium slag.

[0003] Existing magnesium slag refining technologies and equipment mostly use a single stirring paddle to mix magnesium slag with refining reagents. Magnesium slag particles are prone to agglomeration, and the reagents cannot penetrate into the particles, resulting in incomplete reaction, some valuable metals are not dissolved, and the recovery rate is low.

[0004] Secondly, heating during the refining process can promote the reaction and subsequent separation. In the mixture of solution and residue formed after the reaction, a single filtration or precipitation method is often used for separation, which makes it difficult to completely remove the fine particles of residue suspended in the solution, affecting the purity of the subsequent metal purification. In addition, the separation process requires the addition of flocculants, which increases costs and easily introduces impurities.

[0005] The existing process requires multiple independent operations such as crushing, soaking, stirring, heating, filtering, and sedimentation. The material transfer between each step is time-consuming, the heating temperature control is unstable, and the energy consumption is high throughout the process, making it difficult to achieve large-scale production. Summary of the Invention

[0006] In view of this, the present invention aims to provide a magnesium slag refining device that can improve the crushing and grading accuracy of magnesium slag, improve the sufficiency of the mixing reaction, and thus improve the separation and purification effect of valuable metals.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A magnesium slag refining device includes a pretreatment unit, a mixing and reaction unit, a heating and separation unit, a collection unit, and a control system; The pretreatment unit includes a primary crushing device, a buffer silo, a secondary crushing device, and a conveying device connected in sequence; the primary crushing device is equipped with a screening mechanism at its bottom. The primary crushing device has a first outlet, and the conveying device has a second outlet at its tail end. The mixing reaction unit includes a reaction vessel, and a first mixing section and a second mixing section disposed vertically within the reaction vessel; The heating and separation unit is arranged in sequence with a preheating zone, a reaction zone, and a separation zone; The collection unit includes a liquid receiving tank located at the liquid outlet of the separation zone and a collection tank located at the material outlet of the separation zone.

[0008] Furthermore, the preprocessing unit also includes a base frame, a first housing and a second housing disposed above the base frame; The first box includes a shell and a support plate disposed on the upper part of the shell. A feeding space is formed between the support plate and the shell. The inlet of the feeding space is provided with two relatively rotating swing plates and a first drive unit disposed on the first box. The power output end of the first drive unit is used to drive the swing plates to rotate so as to push the material into the feeding space.

[0009] Furthermore, the primary crushing device includes a first crushing hood located at the outlet end of the feed space; The first chamber is equipped with a crushing roller pivotally connected to the upper and lower parts of the first chamber, and the first crushing cover is sleeved on the outside of the crushing roller; The first crushing hood has a feed inlet at the top and a discharge outlet at the bottom. The lower part of the shell is formed with a material guiding space, and the material outlet is located in the material guiding space.

[0010] Furthermore, the lower end of the housing is also provided with a sieve plate, and the sieve plate is provided with a plurality of sieving holes; Several buffer hoppers are disposed below the sieve plate and arranged along the length of the sieve plate; A vibration mechanism is provided at the bottom of the housing.

[0011] Furthermore, the secondary crushing device includes a second crushing hood connected to the outlet end of the buffer hopper, and two crushing shafts pivotally connected to the second housing, with the outlet of the second crushing hood located above the conveying device.

[0012] Furthermore, the inner cavity of the reaction vessel is provided with a sealing corner plate, which divides the inner cavity into an upper and lower stirring chamber and a reaction chamber; The reaction vessel is equipped with a first feed pipe and a second feed pipe, both of which are connected to the reaction chamber. The first mixing section includes a second driving section disposed on the sealing corner plate and a stirring blade disposed at the power output end of the second driving section, the stirring blade being inclinedly disposed in the mixing chamber.

[0013] Furthermore, the second mixing section includes a third driving section provided on the upper part of the reaction vessel, and the power output end of the third driving section is connected to a stirring frame, which is vertically and downwardly arranged on the upper part of the stirring blade; Below the sealing corner plate, there is also a horizontal blocking plate arranged radially along the reaction vessel, and the horizontal blocking plate and the bottom of the reaction vessel form a sedimentation chamber; The reaction vessel is provided with a liquid outlet at the bottom, the sedimentation chamber is connected to the liquid outlet, and the liquid outlet is provided with a screw conveyor.

[0014] Furthermore, the heating separation unit includes a heating tank, an outer heating tube disposed outside the heating tank, and an inner heating tube disposed inside the heating tank; The heating tank is equipped with an inclined material leakage plate and a partition plate; The material leakage plate is the preheating zone, the reaction zone is formed between the material leakage plate and the partition plate, and the separation zone is formed below the partition plate; The bottom of the heating tank is provided with a fourth driving part and a stirring shaft connected to the fourth driving part. The separation zone is provided with a filter screen that surrounds the outside of the stirring shaft. The outside of the filter screen is provided with an adsorption layer that is covered and adhered. The discharge port is located within the space enclosed by the filter screen and the stirring shaft, and the liquid outlet is located outside the filter screen.

[0015] Compared with the prior art, the present invention has the following advantages: The magnesium slag refining device of this invention precisely crushes lumpy magnesium slag into coarse and fine particles. Screening prevents impurities such as coke powder adhering to the surface of the magnesium slag from being mixed in, effectively avoiding over-crushing or under-crushing, thus providing conditions for sufficient contact between the magnesium slag and the reagents. The pretreatment unit adopts a two-stage crushing structure with an intermediate buffer hopper to provide uniform raw materials for subsequent mixing reactions. The mixing reaction unit has a first mixing section and a second mixing section distributed vertically; this dual mixing structure ensures sufficient contact between the magnesium slag and the refining reagents, enhancing the reaction effect. The heating and separation unit achieves gradient treatment through the sequential arrangement of the preheating zone, reaction zone, and separation zone, improving the purity of the target substance separation. The collection unit collects liquid and material from the outlet of the separation zone separately, achieving classified collection of solution and solid products, improving resource recovery and utilization rate.

[0016] Another object of the present invention is to provide a refining method based on the magnesium slag refining apparatus described above, comprising the following steps: Step 1: Magnesia slag pretreatment. Crush the lumpy magnesium slag into particles with a diameter of ≤5mm, remove the coke powder adhering to the surface, and classify it into coarse particles of 2~5mm and fine particles of ≤2mm. Step two, mixing reaction: The coarse and fine magnesium slag particles obtained in step one are separately fed into a mixing tank, with the feed rate monitored by a flow sensor. Simultaneously, a metering pump is used to feed the refining reagent and hydrochloric acid solution (concentration 15% to 20%) into the mixing tank at a mass ratio of 1:3 to 1:5 according to the feed rate. The first mixing section is started, tilted at an angle of 20° to 30°, with a stirring speed of 200 to 330 r / min and a stirring time of 5 to 10 min. Then, the second mixing section is started, with a stirring speed of 200 to 300 r / min and a stirring time of 5 to 10 min, to ensure that the magnesium slag and reagent are fully mixed and reacted. Step 3: Gradient heating separation, utilizing the difference in solubility between CaCl2 and MgCl2 with temperature. The solubility of MgCl2 increases significantly with increasing temperature, while the solubility of CaCl2 changes more gradually. First, the mixture is evaporated to a concentration of 40% to 45%, then cooled to 5 to 15°C. CaCl2 is preferentially precipitated, and CaCl2 crystals are obtained by centrifugation. The remaining mother liquor is further evaporated and concentrated, then heated to 80 to 90°C to remove some water. After cooling, MgCl2 crystals are precipitated, and the product is obtained by centrifugation. Step 4: Drying and packaging. CaCl2 and MgCl2 crystals are precipitated at 120-150℃ and MgCl2 crystals are precipitated at 50-120℃, respectively. After removing the water of crystallization, the product is packaged as the finished product.

[0017] The magnesium slag refining method of this invention controls and classifies the particle size of magnesium slag through pretreatment, providing high-purity, uniformly sized raw materials for subsequent mixing reactions. This avoids the impact of impurities and particle size differences on reaction efficiency, thus improving product purity. Gradient stirring in a dual mixing section and control of the ratio of hydrochloric acid solution to magnesium slag particles ensure thorough mixing and reaction of materials and reagents, improving reaction conversion rate and shortening reaction time. Furthermore, by utilizing the difference in solubility of CaCl2 and MgCl2 with temperature, a gradient separation process of evaporation concentration, cooling precipitation, and re-evaporation cooling is employed to achieve efficient separation of the two substances with high purity. The process is simple and easy to operate, reducing separation costs. Finally, differentiated drying temperatures are used for the two crystals to precisely remove water of crystallization, ensuring product quality. This refining method features tightly integrated steps, combining soaking and stirring in the mixing reaction step and heating, filtration, and precipitation in the separation step. This reduces the cost of multiple equipment in traditional processes, achieving an automated and efficient magnesium slag refining method. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1This is a schematic diagram of the magnesium slag refining device according to an embodiment of the present invention; Figure 2 This is a cross-sectional schematic diagram of the preprocessing unit described in an embodiment of the present invention; Figure 3 This is a three-dimensional schematic diagram of the preprocessing unit described in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the mixing reaction unit described in an embodiment of the present invention; Figure 5 This is a schematic diagram of the heating separation unit described in an embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Pretreatment unit; 2. Mixing and reaction unit; 3. Heating and separation unit; 4. Collection unit; 5. Screw conveyor; 101. Primary crushing device; 102. Buffer silo; 103. Secondary crushing device; 104. Conveying device; 105. Screening mechanism; 106. Base frame; 107. First housing; 108. Second housing; 109. Swinging plate; 110. First drive unit; 201. Reaction vessel; 202. First mixing section; 203. Settling chamber; 204. Sealing plate; 205. First feed pipe; 206. Second feed pipe; 207. Second drive section; 208. Stirring blade; 209. Horizontal blocking plate; 301. Preheating zone; 302. Reaction zone; 303. Separation zone; 304. Heating tank; 305. Outer heating tube; 306. Inner heating tube; 307. Inclined discharge plate; 308. Divider plate; 309. Fourth drive unit; 310. Stirring shaft; 311. Filter screen; 312. Adsorption layer; 401. Liquid receiving tank; 402. Collection tank; 1011. First crushing hood; 1012. Crushing roller; 1013. Feed inlet; 1014. Discharge outlet; 1015. Material guiding space; 1016. Screen plate; 1017. Vibration mechanism; 1018. First outlet; 1019. Second outlet; 1031. Second crushing hood; 1032. Crushing shaft; 1071. Shell; 1072. Support plate; 1073. Feeding space; 2021, Third drive unit; 2022, Mixing rack. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "back," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] Furthermore, in the description of this invention, unless otherwise explicitly defined, the terms "installation," "connection," "linking," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention in light of the specific circumstances.

[0023] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0024] This embodiment relates to a magnesium slag refining device, which, as a whole, is as follows: Figure 1 As shown, the device includes a pretreatment unit 1, a mixing and reaction unit 2, a heating and separation unit 3, a collection unit 4, and a control system. The pretreatment unit 1 includes a primary crushing device 101, a buffer silo 102, a secondary crushing device 103, and a conveying device 104 connected in sequence; the primary crushing device 101 has a screening mechanism 105 at its bottom. The primary crushing device 101 has a first outlet 1018 at its outlet, and the conveying device 104 has a second outlet 1019 at its tail end. The mixing and reaction unit 2 includes a reaction tank 201, and a first mixing section 202 and a second mixing section arranged vertically within the reaction tank 201. The heating and separation unit 3 includes a preheating zone 301, a reaction zone 302, and a separation zone 303 arranged in sequence. The collection unit 4 includes a liquid receiving tank 401 located at the liquid outlet of the separation zone 303, and a collection tank 402 located at the discharge outlet 1014 of the separation zone 303.

[0025] Based on the above design concept, the magnesium slag refining device in this embodiment precisely crushes blocky magnesium slag into coarse and fine particles. Screening prevents impurities such as coke powder adhering to the surface of the magnesium slag from being mixed in, effectively avoiding over-crushing or insufficient crushing, thus providing conditions for sufficient contact between the magnesium slag and the reagents. The pretreatment unit 1 adopts a two-stage crushing structure with an intermediate buffer hopper 102, providing uniform raw materials for subsequent mixing reactions. The mixing reaction unit 2 has a first mixing section 202 and a second mixing section distributed vertically; this dual mixing structure ensures sufficient contact between the magnesium slag and the refining reagents, enhancing the reaction effect. The heating and separation unit 3, through the sequential arrangement of the preheating zone 301, reaction zone 302, and separation zone 303, achieves gradient treatment, improving the purity of the target substance separation. The collection unit 4 collects the liquid and material from the outlet 1014 of the separation zone 303 separately, achieving classified collection of solution and solid products, improving resource recovery and utilization.

[0026] Based on the above overall introduction, an exemplary structure of the magnesium slag refining device in this embodiment is as follows: Figure 1 As shown, the pretreatment unit 1 also includes a base frame 106, a first housing 107 and a second housing 108 disposed above the base frame 106; the first housing 107 includes a shell 1071 and a support plate 1072 disposed on the upper part of the shell 1071, forming a feeding space 1073 between the support plate 1072 and the shell 1071, the inlet of the feeding space 1073 is provided with two relatively rotating swing plates 109, and a first drive unit 110 disposed on the first housing 107, the power output end of the first drive unit 110 is used to drive the swing plates 109 to rotate, so as to push the material into the feeding space 1073. The control system of this embodiment adopts a PLC controller, which is electrically connected to the flow sensor, temperature sensor, pH sensor and other sensors installed in the above-mentioned units, for controlling and monitoring the operating status of each unit.

[0027] like Figures 1 to 3 As shown, in this embodiment, the first drive unit 110 adopts a servo motor. When the magnesium slag raw material is conveyed to the upper part of the support plate 1072, the first drive unit 110 drives the swing plates 109 on both sides to push the raw material towards the center and move it into the feeding space 1073. This achieves orderly material pushing, avoids blockage at the inlet of the feeding space 1073, reduces the accumulation of material in the feeding space 1073, ensures uniform feeding, provides a guarantee for the stability of subsequent crushing and screening, and thus improves pretreatment efficiency.

[0028] Furthermore, such as Figures 1 to 3As shown, the primary crushing device 101 includes a first crushing cover 1011 located at the outlet end of the feeding space 1073. A crushing roller 1012, pivotally connected to the first housing 107, is housed within the first housing 107, and the first crushing cover 1011 is fitted over the outside of the crushing roller 1012. The first crushing cover 1011 has a feed inlet 1013 at its upper part and a discharge outlet 1014 at its lower part. A guiding space 1015 is formed at the lower part of the housing 1071, and the discharge outlet 1014 is located within the guiding space 1015. A screening mechanism 105 has a fixed end located on the second housing 108 and a movable end located at the bottom of the first housing 107. A plurality of screening holes are formed on the support plate 1072.

[0029] Specifically, such as Figure 1 As shown, both the first housing 107 and the second housing 108 have irregularly shaped cavities. The shell 1071 is the irregularly shaped first housing 107, and the support plate 1072 is a planar plate structure arranged along the width of the first housing 107, gradually sloping downwards from the feed inlet 1013 towards the first crushing hood 1011. Furthermore, the support plate 1072 is provided with a discharge hole to separate the coke powder floating on the surface during the magnesium slag operation.

[0030] The primary crushing device 101 adopts a structure of two crushing rollers 1012 and a first crushing hood 1011. The material enters from the feed inlet 1013 and is squeezed by the two crushing rollers 1012 to crush the blocky magnesium slag. Impact and shearing forces are applied to the material in the closed space of the first crushing hood 1011. The rotating crushing rollers 1012 cause some of the material to be repeatedly impacted and crushed in the limited area, thereby improving the crushing efficiency.

[0031] Preferably, such as Figures 1 to 3 As shown, a sieve plate 1016 is also provided at the lower end of the shell 1071, and the sieve plate 1016 has several screening holes. Several buffer hoppers 102 are arranged below the sieve plate 1016 and along the length of the sieve plate 1016. A vibration mechanism 1017 is provided below the shell 1071. The sieve plate 1016 at the lower end of the shell 1071 and the screening holes of the support plate 1072 form a double screening, allowing particles ≤5mm to enter the buffer hoppers 102, providing equal raw materials for secondary crushing.

[0032] Meanwhile, multiple buffer hoppers 102 are arranged along the length of the screen plate 1016 to achieve separate storage of the screened material, avoiding material mixing, and also buffering the crushing rhythm to prevent material accumulation or interruption. Figure 1 As shown, the vibration mechanism 1017 below the housing 1071 adopts a conventional structure, such as an eccentric vibrator. The vibration mechanism 1017 drives the screen plate 1016 to vibrate, thereby improving screening efficiency and reducing material adhesion and clogging on the screen plate 1016.

[0033] Preferably, the secondary crushing device 103 includes a second crushing cover 1031 connected to the outlet end of the buffer hopper 102, and two crushing shafts 1032 pivotally connected to the second housing 108. The outlet of the second crushing cover 1031 is located above the conveying device 104. The crushing shafts 1032 are equipped with crushing blades. The relative rotation of the two crushing shafts 1032 enhances the shearing and crushing effect, ensuring that the magnesium slag particles reach a fine particle size of ≤2mm.

[0034] like Figure 1 and Figure 4 As shown, the inner cavity of the reaction vessel 201 is equipped with a sealing corner plate 204, which divides the inner cavity into an upper and lower stirring chamber and a reaction chamber. The reaction vessel 201 is equipped with a first feeding pipe 205 and a second feeding pipe 206, both of which communicate with the reaction chamber. The first mixing section 202 includes a second drive section 207 mounted on the sealing corner plate 204, and a stirring blade 208 located at the power output end of the second drive section 207. The stirring blade 208 is inclinedly disposed within the stirring chamber. Both the second drive section 207 and the third drive section 2021 described below employ servo motors to provide rotational power to the stirring blade 208 and the stirring frame 2022. The stirring blade 208 has upward-protruding ends and serrated teeth, which, during rotation, create lateral shearing against coarse particles. As the particles are released into the mixture with the flow, the stirring frequency is repeated.

[0035] Preferably, such as Figure 5 As shown, the second mixing section includes a reaction tank 201 with a third drive unit 2021 on its upper part. The power output end of the third drive unit 2021 is connected to a stirring frame 2022, which is vertically downwardly mounted on the upper part of the stirring blades 208. Below the sealing corner plate 204, there is also a horizontal blocking plate 209 arranged radially along the reaction tank 201, which forms a sedimentation chamber 203 with the bottom of the reaction tank 201. The bottom of the reaction tank 201 has a liquid outlet, which communicates with the sedimentation chamber 203. A screw conveyor 5 is installed at the liquid outlet.

[0036] The first outlet 1018 is used to convey coarse particles of 2-5mm, and the second outlet 1019 is used to output fine particles ≤2mm. Flow sensors and regulating valves are installed on both conveying pipelines to control the feed rate and adapt to the appropriate stirring method. Batch-based time-sharing operation is adopted, with the same mixing reactor 201 processing the screened coarse and fine particles at different time periods to ensure the uniformity and consistency of batch processing.

[0037] The reaction chamber has two opposing solution inlets. The first inlet is used to add lime milk (Ca(OH)2) to adjust the pH to 7-8, so that the Al in the solution... 3+ Fe3+ Hydroxide precipitate is formed; sodium fluoride (NaF) is added at the second inlet to remove Ca. 2+ Mg 2+ SiO3 2- Finally, a pure mixture of CaCl2 and MgCl2 was obtained.

[0038] Preferably, the heating and separation unit 3 includes a heating tank 304, an outer heating pipe 305 disposed outside the heating tank 304, and an inner heating pipe 306 disposed inside the heating tank 304. The heating tank 304 contains an inclined material leakage plate 307 and a partition plate 308. The material leakage plate forms a preheating zone 301, a reaction zone 302 is formed between the material leakage plate and the partition plate 308, and a separation zone 303 is formed below the partition plate 308. The bottom of the heating tank 304 contains a fourth driving unit 309 and a stirring shaft 310 connected to the fourth driving unit 309. A filter screen 311 is disposed within the separation zone 303, surrounding the outside of the stirring shaft 310, and an adsorption layer 312 is provided on the outside of the filter screen 311. An outlet 1014 is disposed within the space enclosed by the filter screen 311 and the stirring shaft 310, and a liquid outlet is disposed outside the filter screen 311.

[0039] The fourth drive unit 309 uses a servo motor to drive the stirring shaft 310 to rotate. Figure 4 As shown, the heating element in this embodiment uses electric heating, with double-layer heating of the outer heating element 305 and the inner heating element 306, improving heating efficiency, meeting the temperature requirements for material concentration, and avoiding decomposition or side reactions of the target substance due to local overheating. The inclined discharge plate 307 and the separator plate 308 form a preheating zone 301, a reaction zone 302, and a separation zone 303, enabling the material to complete a gradient process of preheating, reaction, and solid-liquid separation. The separation zone 303 generates centrifugal force through the stirring of the stirring shaft 310, which can quickly push the solid crystals inside the filter screen 311 towards the discharge port 1014, preventing crystals from accumulating and clogging the filter screen 311.

[0040] In addition, since multiple blades are arranged radially on the stirring shaft 310, small agglomerates are easily formed after crystal precipitation due to intermolecular forces. During static separation, the agglomerates can easily clog the pores of the filter screen 311. By setting a stirrer inside the filter screen 311, a slight shearing force is applied to the crystal agglomerates, allowing the crystals to pass through the filter screen 311 in the form of single particles or small particle clusters, ensuring that the mother liquor is smoothly discharged from the outlet.

[0041] In addition, this embodiment also relates to a refining method using the above-mentioned magnesium slag refining device, including the following steps: Step 1: Magnesia slag pretreatment. Crush the lumpy magnesium slag into particles with a diameter of ≤5mm, remove the coke powder adhering to the surface, and classify it into coarse particles of 2~5mm and fine particles of ≤2mm. Step two, mixing reaction: The magnesium slag particles obtained in step one are fed into a mixing tank separately, with coarse and fine particles, and the feed rate is monitored by a flow sensor. At the same time, a metering pump is used to feed the refining reagent and hydrochloric acid solution (concentration 15% to 20%) into the mixing tank according to the feed rate at a mass ratio of 1:3 to 1:5. The first mixing section 202 is started, tilted at an angle of 20° to 30°, with a stirring speed of 200 to 330 r / min and a stirring time of 5 to 10 min. Then the second mixing section is started, with a stirring speed of 200 to 300 r / min and a stirring time of 5 to 10 min, so that the magnesium slag and reagent are fully mixed and reacted. More specifically, the coarse particle input reaction tank 201 adopts a dual-mixing section combined stirring mode. The coarse particles are fed into the mixing reaction tank 201 at a speed of 8~10 kg / min, and the first mixing section 202 and the second mixing section are started after a 2-second delay. The stirring blades 208 rotate counterclockwise at a speed of 300~330 r / min, with the tilt angle set at 25°~30°, and shear and scrape the surface of the coarse particles while churning the material upward.

[0042] The stirring rack 2022 rotates clockwise and counterclockwise at a speed of 240~260 r / min, with the horizontal bar spacing reduced to 4 cm. This, combined with a 55 Hz vibration frequency, enhances dispersion. An 18%~20% hydrochloric acid solution is continuously injected, with the reagent to coarse particle mass ratio controlled at 1:4.8~1:5, and the droplet size at 70~90 μm. After feeding, the dual mixing section continuously stirs for 15~18 min to ensure sufficient reaction of the coarse particles. Finally, the material is rapidly discharged via screw conveyor 5 at a speed of 15~18 r / min, with a discharge time of 3~5 min.

[0043] After the coarse particle batch processing is completed, the tank is rinsed with clean water for 30 seconds, then switched to the fine particle processing mode, using a single mixing section for independent stirring. Fine particles are fed at a rate of 15-18 kg / min, and simultaneously the second mixing section is started, rotating clockwise at a high speed of 280-300 r / min, with a horizontal bar spacing of 3.5 cm and a vibration frequency increased to 65 Hz, rapidly breaking up fine particle agglomerates. A 15%-17% hydrochloric acid solution is used as the reagent, atomized and injected at a mass ratio of 1:3-1:3.2, with droplet diameters of 40-60 μm, and started and stopped synchronously with the feeding. After feeding, the stirring rack 2022 runs continuously for 8-10 minutes, followed by rapid discharge from the screw conveyor 5 at a speed of 12-15 r / min, emptying in 2-3 minutes to begin the next cycle. The agglomeration rate is ≤0.3%, the reaction cycle is shortened, and the product purity is stable.

[0044] Step 3: Gradient heating separation. Utilizing the difference in solubility between CaCl2 and MgCl2 with temperature, the solubility of MgCl2 increases significantly with increasing temperature, while the solubility of CaCl2 changes more gradually. First, the mixture is evaporated to a concentration of 40%–45%, then cooled to 5–15°C. CaCl2 preferentially precipitates, and CaCl2 crystals are obtained by centrifugation. The remaining mother liquor is further evaporated and concentrated, then heated to 80–90°C to remove some water. After cooling, MgCl2 crystals precipitate, and the product is obtained by centrifugation. Step 4: Drying and packaging. CaCl2 and MgCl2 crystals are precipitated at 120-150℃ and MgCl2 crystals are precipitated at 50-120℃, respectively. After removing the water of crystallization, the product is packaged as the finished product.

[0045] The magnesium slag refining method of this invention controls and classifies the particle size of magnesium slag through pretreatment, providing high-purity, uniformly sized raw materials for subsequent mixing reactions. This avoids the impact of impurities and particle size differences on reaction efficiency, thus improving product purity. Gradient stirring in a dual mixing section and control of the ratio of hydrochloric acid solution to magnesium slag particles ensure thorough mixing and reaction of materials and reagents, improving reaction conversion rate and shortening reaction time. Furthermore, by utilizing the difference in solubility of CaCl2 and MgCl2 with temperature, a gradient separation process of evaporation concentration, cooling precipitation, and re-evaporation cooling is employed to achieve efficient separation of the two substances with high purity. The process is simple and easy to operate, reducing separation costs. Finally, differentiated drying temperatures are used for the two crystals to precisely remove water of crystallization, ensuring product quality. This refining method features tightly integrated steps, combining soaking and stirring in the mixing reaction step and heating, filtration, and precipitation in the separation step. This reduces the cost of multiple equipment in traditional processes, achieving an automated and efficient magnesium slag refining method.

[0046] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A magnesium slag refining device, characterized in that: It includes a pretreatment unit (1), a mixing and reaction unit (2), a heating and separation unit (3), a collection unit (4), and a control system; The pretreatment unit (1) includes a primary crushing device (101), a buffer silo (102), a secondary crushing device (103), and a conveying device (104) connected in sequence; the primary crushing device (101) is provided with a screening mechanism (105) at the bottom. The primary crushing device (101) has a first outlet (1018) at its outlet, and the conveying device (104) has a second outlet (1019) at its tail end. The mixing reaction unit (2) includes a reaction vessel (201), and a first mixing section (202) and a second mixing section disposed vertically within the reaction vessel (201); The heating and separation unit (3) is arranged with a preheating zone (301), a reaction zone (302) and a separation zone (303) in sequence. The collection unit (4) includes a liquid receiving tank (401) located at the liquid outlet of the separation zone (303) and a collection tank (402) located at the discharge outlet (1014) of the separation zone (303).

2. The magnesium slag refining apparatus according to claim 1, characterized in that: The preprocessing unit (1) also includes a base frame (106), a first housing (107) and a second housing (108) disposed above the base frame (106); The first housing (107) includes a shell (1071) and a support plate (1072) disposed on the upper part of the shell (1071). A feeding space (1073) is formed between the support plate (1072) and the shell (1071). The inlet of the feeding space (1073) is provided with two relatively rotating swing plates (109) and a first drive unit (110) disposed on the first housing (107). The power output end of the first drive unit (110) is used to drive the swing plates (109) to rotate so as to push the material into the feeding space (1073).

3. The magnesium slag refining apparatus according to claim 2, characterized in that: The primary crushing device (101) includes a first crushing hood (1011) located at the outlet end of the feed space (1073). The first housing (107) is provided with a crushing roller (1012) pivotally connected to the first housing (107) from top to bottom, and the first crushing cover (1011) is sleeved on the outside of the crushing roller (1012); The first crushing hood (1011) is provided with a feed inlet (1013) at the top and a discharge outlet (1014) at the bottom. The lower part of the shell (1071) is formed with a material guiding space (1015), and the material outlet (1014) is disposed in the material guiding space (1015); The fixed end of the screening mechanism (105) is located on the second box (108), and the movable end is located at the bottom of the first box (107); The support plate (1072) has several screening holes formed on it.

4. The magnesium slag refining apparatus according to claim 3, characterized in that: The lower end of the shell (1071) is also provided with a sieve plate (1016), and the sieve plate (1016) is provided with a plurality of sieving holes; Several buffer hoppers (102) are disposed below the sieve plate (1016) and arranged along the length of the sieve plate (1016); A vibration mechanism (1017) is provided below the housing (1071).

5. The magnesium slag refining apparatus according to claim 2, characterized in that: The secondary crushing device (103) includes a second crushing cover (1031) connected to the outlet end of the buffer hopper (102) and two crushing shafts (1032) pivotally connected to the second housing (108). The outlet of the second crushing cover (1031) is located above the conveying device (104).

6. The magnesium slag refining apparatus according to claim 5, characterized in that: The inner cavity of the reaction vessel (201) is provided with a sealing corner plate (204), which divides the inner cavity into an upper and lower stirring chamber and a reaction chamber. The reaction vessel (201) is provided with a first feeding pipe (205) and a second feeding pipe (206), both of which are connected to the reaction chamber. The first mixing section (202) includes a second driving section (207) disposed on the sealing corner plate (204) and a stirring blade (208) disposed at the power output end of the second driving section (207), the stirring blade (208) being inclinedly disposed in the mixing chamber.

7. The magnesium slag refining apparatus according to claim 6, characterized in that: The second mixing section includes a third driving section (2021) provided on the upper part of the reaction vessel (201). The power output end of the third driving section (2021) is connected to a stirring frame (2022), which is vertically and downwardly arranged on the upper part of the stirring blade (208). Below the sealing corner plate (204), there is also a horizontal blocking plate (209) arranged radially along the reaction vessel (201), and the horizontal blocking plate (209) and the bottom of the reaction vessel (201) form a sedimentation chamber (203). The reaction vessel (201) is provided with a liquid outlet at the bottom, the sedimentation chamber (203) is connected to the liquid outlet, and the liquid outlet is provided with a screw conveyor (5).

8. The magnesium slag refining apparatus according to claim 7, characterized in that: The heating separation unit (3) includes a heating tank (304), an outer heating tube (305) disposed outside the heating tank (304), and an inner heating tube (306) disposed inside the heating tank (304). The heating tank (304) is provided with an inclined material leakage plate (307) and a partition plate (308). The material leakage plate is the preheating zone (301), the reaction zone (302) is formed between the material leakage plate and the partition plate (308), and the separation zone (303) is formed below the partition plate (308). The bottom of the heating tank (304) is provided with a fourth driving part (309) and a stirring shaft (310) connected to the fourth driving part (309). The separation zone (303) is provided with a filter screen (311) surrounding the outside of the stirring shaft (310). The filter screen (311) is provided with an adsorption layer (312) covering and adhering to the outside. The discharge port (1014) is located within the space enclosed by the filter screen (311) and the stirring shaft (310), and the liquid outlet is located outside the filter screen (311).

9. A refining method based on the magnesium-slag refining apparatus according to any one of claims 1 to 8, characterized by, Includes the following steps: Step 1: Magnesia slag pretreatment. Crush the lumpy magnesium slag into particles with a diameter of ≤5mm, remove the coke powder adhering to the surface, and classify it into coarse particles of 2~5mm and fine particles of ≤2mm. Step 2, mixing reaction: The magnesium slag particles obtained in Step 1 are fed into a mixing tank separately, with the coarse and fine particles being fed into the mixing tank. The feed rate is monitored by a flow sensor. At the same time, a metering pump is used to feed the refining reagent and hydrochloric acid solution with a concentration of 15% to 20% into the mixing tank according to the feed rate at a mass ratio of 1:3 to 1:

5. The first mixing section (202) is started, with the first mixing section (202) tilted at an angle of 20° to 30°, the stirring speed at 200 to 330 r / min, and the stirring time at 5 to 10 min. Then the second mixing section is started, with the stirring speed at 200 to 300 r / min and the stirring time at 5 to 10 min, so that the magnesium slag and the reagent are fully mixed and reacted. Step 3: Gradient heating separation, utilizing the difference in solubility between CaCl2 and MgCl2 with temperature. The solubility of MgCl2 increases significantly with increasing temperature, while the solubility of CaCl2 changes more gradually. First, the mixture is evaporated to a concentration of 40% to 45%, then cooled to 5 to 15°C. CaCl2 is preferentially precipitated, and CaCl2 crystals are obtained by centrifugation. The remaining mother liquor is further evaporated and concentrated, then heated to 80 to 90°C to remove some water. After cooling, MgCl2 crystals are precipitated, and the product is obtained by centrifugation. Step 4: Drying and packaging. CaCl2 and MgCl2 crystals are precipitated at 120-150℃ and MgCl2 crystals are precipitated at 50-120℃, respectively. After removing the water of crystallization, the product is packaged as the finished product.

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