A method for preparing qualified vanadium leachate from high-iron-vanadium slag

Abstract

This invention relates to the field of sponge titanium production technology, specifically a method for preparing qualified vanadium leachate from high-iron-content vanadium slag. This method adds a crystallization and iron removal step to the existing acid leaching vanadium extraction process. Utilizing the difference in solubility between ferrous chloride and vanadium compounds in the hydrochloric acid system, the method can stably treat vanadium leachate with a high ferrous ion concentration, significantly reducing the ferrous ion content in the leachate. This completely solves the problem of co-precipitation of high-concentration iron ions during the oxidation hydrolysis and pyrolysis vanadium precipitation processes, effectively avoiding the contamination of intermediate materials and the final vanadium pentoxide product by iron impurities. It ensures that all indicators of the vanadium product meet industry quality standards, breaks through the limitations of traditional processes on the iron content of vanadium slag, and broadens the applicable range of raw materials.

Description

Technical Field

[0001] This invention relates to the field of sponge titanium production technology, and more specifically, to a method for preparing qualified vanadium leachate from high-iron-vanadium slag. Background Technology

[0002] In the production of sponge titanium, the purification of crude titanium tetrachloride is one of the core processes. Vanadium impurities in crude titanium tetrachloride mainly exist in the form of VOCl3. Industrially, the removal of vanadium is generally achieved by adding organic matter. The vanadium-containing slurry generated by the reaction is dried to obtain vanadium-removed slag. This vanadium-removed slag is an important secondary resource for recovering metallic vanadium. Several industrialized process solutions have been developed in the industry for vanadium extraction from titanium tetrachloride vanadium-removed slag.

[0003] Currently, patent document CN119392008A discloses a method for recovering vanadium from titanium tetrachloride vanadium removal slag. This patented technology uses a complete process of acid leaching, oxidative hydrolysis, pyrolysis precipitation of vanadium, alkaline leaching, precipitant precipitation of vanadium, and roasting to prepare vanadium pentoxide. It has the advantages of a simple process flow and an environmentally friendly production process, and has been applied to some extent in the field of vanadium extraction from titanium tetrachloride vanadium removal slag with conventional compositions. However, this patented technology has obvious limitations. Its process requires that the total content of ferric oxide and titanium dioxide in the raw vanadium slag be less than 20%, and sets a strict threshold for the iron content of the vanadium slag.

[0004] In actual industrial continuous production scenarios, the composition of upstream high-titanium slag raw materials is prone to fluctuations, and the quality of crude titanium tetrachloride products is difficult to maintain consistently. This ultimately leads to the iron content of the produced titanium tetrachloride vanadium-removing slag significantly exceeding the aforementioned limits. When using the patented process CN119392008A to treat high-iron vanadium-removing slag, the ferrous ion concentration in the vanadium leachate obtained after acid leaching often exceeds 30 g / L. In subsequent oxidation hydrolysis and pyrolysis precipitation processes, the high concentration of iron ions hydrolyzes simultaneously with the vanadium components, forming a co-precipitation phenomenon. A large amount of iron impurities mix into the vanadium precipitate, severely contaminating the intermediate products and the final vanadium pentoxide product, causing the vanadium product purity to fail to meet industry standards. Therefore, the existing traditional vanadium extraction process represented by CN119392008A cannot meet the processing requirements of high-iron vanadium slag. The industry urgently needs to develop a new vanadium extraction process that can stably process high-iron vanadium slag and produce a low-iron, qualified vanadium leachate. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing qualified vanadium leachate from high-iron-vanadium slag, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides a method for preparing qualified vanadium leaching solution from high-iron-vanadium slag, comprising the following process steps performed sequentially:

[0007] S1. The vanadium-removed slag produced from titanium tetrachloride production is put into the acid system and stirred leaching is carried out using a stirring leaching device. The vanadium and iron components are dissolved by the acid solution. After leaching, the first solid-liquid separation device is used to separate the solid and liquid components, and the vanadium-iron leaching solution and solid leaching slag are obtained. The solid leaching slag is disposed of externally.

[0008] S2. Add ferrous chloride crystals to the vanadium-iron leaching solution obtained in S1, and send it to a stirring and mixing device to completely dissolve the crystals. The mixture is then sent to an evaporation and concentration device for high-temperature evaporation and concentration to increase the concentration of ferrous ions in the system so that ferrous chloride reaches a supersaturated state, thereby obtaining a high iron-vanadium solution. This step utilizes the difference in solubility between ferrous chloride and vanadium compounds in the hydrochloric acid system to enrich the iron component.

[0009] S3. The high iron-vanadium solution produced in S2 is transported to a cooling crystallization device. The supersaturated ferrous chloride crystals are precipitated by low-temperature temperature control, thus completing the transformation of the iron component from the liquid phase to the solid phase.

[0010] S4. The solid-liquid suspension formed in S3 is introduced into the second solid-liquid separation device to carry out solid-liquid separation, and ferrous chloride crystals and a high vanadium content solution that meets the vanadium extraction standard are obtained.

[0011] S5. The ferrous chloride crystals separated in S4 are sequentially fed into a countercurrent washing device and a hot air drying device to complete water washing and drying. The water washing uses the condensate generated by the evaporation and concentration device as the medium. The dried ferrous chloride crystals are distributed by the material diversion device. Part of them are returned to the stirring and mixing device for recycling, and the other part is sent to the tail gas treatment process of the chlorination process to prepare ferrous chloride solution, so as to realize the recycling of materials. This method adds a crystallization iron removal process to the original acid leaching vanadium extraction process without changing the original main process path. By reducing the ferrous ion content of the leaching solution through crystallization separation, the adverse effects of iron components on the subsequent vanadium precipitation process and the purity of vanadium products are avoided.

[0012] This setup relies on the entire process of iron removal through crystallization, and can be adapted to the processing requirements of vanadium slag raw materials with high iron content. Without changing the original mature vanadium extraction process, it effectively removes ferrous ions from the leachate, preventing iron impurities from contaminating vanadium products from the source. At the same time, it realizes the recycling of ferrous chloride materials and reduces the consumption of production materials.

[0013] Preferably, the stirring leaching device integrates a built-in constant temperature heat exchanger and multiple sets of axial stirring blades. The built-in constant temperature heat exchanger stabilizes the temperature of the leaching system through medium heat exchange, and the multiple sets of axial stirring blades work together to form a full-area material disturbance flow field, ensuring that the vanadium slag particles and acid solution are in continuous and sufficient contact. The material outlet of the stirring leaching device is connected to the feed end of the first solid-liquid separation device through a closed conveying pipeline. The pipeline is equipped with an anti-backflow baffle structure to prevent the separated material from flowing back to the leaching station.

[0014] This setup stabilizes the temperature environment for the leaching reaction, enhances the contact between vanadium slag and acid, improves the leaching efficiency of vanadium and iron components, and at the same time, relies on the pipeline structure to prevent material backflow, ensuring the continuous and stable operation of both the leaching and solid-liquid separation processes.

[0015] Preferably, the stirring and mixing device is equipped with a stepless speed-regulating stirring rod and an annular guide cavity. The stepless speed-regulating stirring rod can adjust the stirring speed to match different liquid states, and the annular guide cavity guides the material to circulate and prevent ferrous chloride crystals from depositing on the bottom wall. The evaporation and concentration device is equipped with a vacuum generating component and an independent temperature control component. The vacuum generating component creates a negative pressure environment inside the device to lower the boiling point of the solution, and the independent temperature control component adjusts and maintains the operating temperature of the concentration station in real time. A gas phase collection chamber is set at the top of the device to collect the condensate generated by evaporation.

[0016] This setting allows for flexible adjustment of the stirring conditions based on the characteristics of the liquid, preventing the settling and accumulation of solid materials. The negative pressure concentration structure reduces material volatilization loss during the high-temperature evaporation process of the solution, stabilizes the concentration conditions, and collects condensate in a unified manner to provide water for the subsequent washing process, thus achieving closed-loop utilization of water resources.

[0017] Preferably, the cooling crystallization device is equipped with a stirrer and an intelligent low-temperature controller. The stirrer drives the solution to circulate continuously, preventing the solute from adhering and forming scale on the inner wall of the cavity. The intelligent low-temperature controller precisely maintains the low-temperature environment required for crystallization. The rear end of the cooling crystallization device is connected to an independent static crystal growth chamber. After the mixture of precipitated crystals enters the static crystal growth chamber, it maintains a static environment to allow the ferrous chloride crystals to grow and form fully. The bottom of the static crystal growth chamber is equipped with a gentle slope material guiding structure to ensure that the material is transported out smoothly.

[0018] This setting prevents solute from forming on the walls during crystallization, thus affecting equipment operation and crystallization effect. Precise temperature control ensures normal precipitation of ferrous chloride. The static crystal growth structure improves crystal forming quality, and the gentle material guiding structure avoids crystal breakage and facilitates subsequent solid-liquid separation operations.

[0019] Preferably, the second solid-liquid separation device uses a centrifugal separation body or a filtration separation body. The centrifugal separation body has a radially layered flow guide chamber inside. After the solid and liquid are separated by centrifugal force, the layered flow guide chamber guides the solid and liquid phase materials to be discharged in a directional manner. The filtration separation body is equipped with a multi-layer graded filter media assembly and a solid phase temporary storage chamber. The multi-layer graded filter media assembly retains ferrous chloride crystals step by step, and the solid phase temporary storage chamber temporarily stores the filtered solid material. The liquid phase outlet of both types of separation bodies is connected to a closed conveying pipeline to transport the high vanadium content solution to the next process.

[0020] This setup offers two selectable solid-liquid separation structures to adapt to different production conditions and material states. The staged interception and directional flow structure can improve the thoroughness of solid-liquid separation, ensure the quality of high vanadium content solutions, and at the same time, orderly transport the two phases of materials to ensure smooth process connections.

[0021] Preferably, the countercurrent washing device is equipped with a double-pass flow chamber and a spiral feeding assembly. The material enters from the head end of the double-pass flow chamber and exits from the tail end, while the washing water enters from the tail end and exits from the head end. The double-pass flow chamber enables the washing water and ferrous chloride crystals to contact in reverse. The spiral feeding assembly pushes the crystals at a uniform speed and enhances the washing contact effect. The hot air drying device includes a hot air generating assembly and a multi-layer mesh support structure. The hot air generating assembly outputs a uniform hot air flow, and the multi-layer mesh support structure carries the crystals and allows the hot air to penetrate the material layer, improving the overall dehydration efficiency. The multi-layer mesh support structure is arranged in an alternating inclined manner, forming a multi-pass inclined channel inside the hot air drying device. One end of the multi-layer mesh support structure is driven by a vibration motor to vibrate. The bottom of the hot air drying device is equipped with a hot air outlet, which is connected to a return air duct. The return air duct is connected to the air inlet of the hot air generating assembly to achieve hot air circulation.

[0022] This setup employs a counter-current washing mode to enhance the cleaning effect of impurities on the crystal surface. The vibrating mesh support structure extends the material drying process and strengthens the material turning effect. The hot air circulation structure can recover waste heat, improve heat energy utilization, and reduce energy consumption in the drying process.

[0023] Preferably, the first solid-liquid separation device adopts a multi-stage stacked filtration structure, with the interception accuracy of each filtration unit increasing progressively. It can intercept vanadium slag residues of different particle sizes in layers. The liquid phase collection chamber of the first solid-liquid separation device is equipped with an online component detection component. The online component detection component has a built-in ion sensing probe and a data transmission module to detect the content of ferrous ions and vanadium pentoxide in the leachate in real time and transmit the detection data to the outside.

[0024] This feature can intercept solid residues of different particle sizes in stages, improving the accuracy of solid-liquid separation. The online detection component can monitor the composition parameters of the leachate in real time, providing data support for parameter adjustment in the subsequent crystallization and iron removal process, and improving the intelligent control level of the entire process.

[0025] Preferably, the evaporation and concentration device is equipped with a mesh foam suppression component, which cuts and breaks up the foam generated during the concentration process to prevent the material from being lost with the gas phase. The device is equipped with an overall heat insulation and covering structure on the outside to reduce heat exchange with the external environment and ensure stable concentration conditions. The gas phase collection chamber is connected to the countercurrent washing device through a dedicated water supply pipeline to realize closed-loop reuse of condensate.

[0026] This feature suppresses foam generation during the concentration process, preventing the loss of effective materials with the gas phase. The insulation structure maintains a stable concentration temperature, further ensuring the evaporation and concentration effect. The pipeline connection structure enables directional delivery and recycling of condensate, improving resource utilization.

[0027] Preferably, the cooling crystallization device is provided with a fully enclosed heat-insulating enclosure structure on the outside to reduce the impact of external temperature fluctuations on the internal crystallization system. The feeding end of the device is equipped with a material buffer chamber, which slows down the feeding flow rate and avoids high-speed feeding impact from damaging the precipitated crystal structure. The material buffer chamber is connected to the main body of the cooling crystallization device by a smooth transition channel.

[0028] This feature isolates external temperature interference, ensuring a constant crystallization environment temperature. The buffer chamber and smooth channel can reduce material impact, protect the integrity of the formed ferrous chloride crystal structure, and guarantee the quality of the crystallized product.

[0029] Preferably, the material diversion device is equipped with a diversion valve body and two independent discharge channels. The diversion valve body switches the material flow direction according to production needs, and the two independent discharge channels are respectively connected to the mixing device and the chlorination process tail gas treatment station.

[0030] This setting allows for flexible switching of the conveying direction of ferrous chloride crystals, enabling the allocation of materials as needed to achieve dual applications of recycling and exhaust gas treatment, adapting to different production scheduling needs, and enhancing the comprehensive utilization value of materials.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. In this method for preparing qualified vanadium leachate from high-iron vanadium slag, a crystallization and iron removal process is added to the original acid leaching vanadium extraction process. By utilizing the difference in solubility between ferrous chloride and vanadium compounds in the hydrochloric acid system, the vanadium leachate with a high concentration of ferrous ions can be stably treated, significantly reducing the ferrous ion content in the leachate. This completely solves the problem of co-precipitation of high-concentration iron ions in the oxidation hydrolysis and pyrolysis vanadium precipitation processes, effectively avoiding the contamination of intermediate materials and the final vanadium pentoxide product by iron impurities, ensuring that all indicators of the vanadium product meet industry quality standards, breaking through the limitations of traditional processes on the iron content of vanadium slag, and broadening the applicable range of raw materials.

[0033] 2. In the method for preparing qualified vanadium leachate from high-iron vanadium slag, the ferrous ions in the leachate are separated and removed in advance, which greatly reduces the processing load of the subsequent oxidation process, significantly reduces the amount of oxidant required for the oxidation process, reduces the cost of chemical raw materials and the overall production and operation cost, and improves the economic benefits of the process.

[0034] 3. In the method for preparing qualified vanadium leachate from high-iron vanadium slag, the newly added crystallization and iron removal equipment can be seamlessly integrated with the original vanadium extraction process without requiring significant modifications to the existing main production line. The equipment modification is simple and cost-effective, making it easy to implement and apply in existing industrial production lines and adapt to continuous and large-scale industrial production models.

[0035] 4. In the method for preparing qualified vanadium leaching solution from high-iron vanadium slag, part of the ferrous chloride crystals precipitated during the process are returned to the front-end process as raw materials for recycling, and the other part is transported to the tail gas treatment process of the chlorination process for reuse. The condensate generated by evaporation and concentration is also recycled for the crystal washing process, realizing the closed-loop recycling of solid and liquid materials, reducing solid waste and wastewater discharge, improving the comprehensive utilization rate of resources, and reducing the cost of waste treatment. The production process is green and environmentally friendly.

[0036] 5. In this method for preparing qualified vanadium leachate from high-iron vanadium slag, the entire process is equipped with a complete temperature control, flow guidance, solid-liquid separation, and online detection structure. The operation of each process is stable, the material transmission is smooth, and the equipment is not prone to problems such as wall slagging, material deposition, and crystal breakage. This effectively extends the service life of the equipment, reduces the frequency and cost of equipment maintenance, and ensures the long-term stable and continuous operation of the production line. Attached Figure Description

[0037] Figure 1 This is a schematic diagram illustrating the overall principle of the present invention;

[0038] Figure 2 This is a schematic diagram of the countercurrent washing device in this invention;

[0039] Figure 3 This is a schematic diagram of the hot air drying device in this invention;

[0040] The meanings of the labels in the diagram are as follows:

[0041] 1. Stirring and leaching device; 2. First solid-liquid separation device; 3. Stirring and mixing device; 4. Evaporation and concentration device; 5. Cooling and crystallization device; 6. Second solid-liquid separation device; 7. Countercurrent washing device; 71. Double-pass flow chamber; 72. Screw feeding assembly; 8. Hot air drying device; 81. Hot air generating assembly; 82. Multi-layer mesh material support structure; 9. Material diversion device. Detailed Implementation

[0042] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0043] This invention provides a method for preparing qualified vanadium leaching solution from high-iron-vanadium slag, such as... Figures 1-3 As shown, the method involves sequentially completing multiple processes S1, S2, S3, S4, and S5 using supporting process equipment. The complete set of process equipment includes a stirring leaching device 1, a first solid-liquid separation device 2, a stirring and mixing device 3, an evaporation and concentration device 4, a cooling and crystallization device 5, a second solid-liquid separation device 6, a countercurrent washing device 7, a hot air drying device 8, and a material diversion device 9. Each piece of equipment is connected sequentially according to the process flow to collaboratively achieve the treatment of high iron and vanadium slag and the preparation of qualified vanadium leaching solution.

[0044] The stirring leaching device 1 is used to complete the stirring leaching operation of titanium tetrachloride vanadium removal slag and acid solution; the first solid-liquid separation device 2 is used to separate the leached material into solid and liquid components; the stirring and mixing device 3 is used to dissolve the added ferrous chloride crystals; the evaporation and concentration device 4 is used to evaporate and concentrate the mixed solution; the cooling crystallization device 5 is used to achieve low-temperature crystallization and precipitation of ferrous chloride; the second solid-liquid separation device 6 is used to separate the solid and liquid suspensions after crystallization; the countercurrent washing device 7 and the hot air drying device 8 sequentially complete the washing and drying of the ferrous chloride crystals; and the material diversion device 9 is used to directionally distribute and transport the dried ferrous chloride crystals.

[0045] The stirring leaching device 1, in conjunction with the first solid-liquid separation device 2, completes the leaching of raw materials and the separation of slag and liquid, producing vanadium-iron leaching solution and solid leaching residue, thereby realizing the extraction of valuable components and the separation of waste residue.

[0046] The stirring and mixing device 3, the evaporation and concentration device 4, and the cooling and crystallization device 5 work in sequence to supplement ferrous chloride into the vanadium-iron leaching solution and concentrate it to a supersaturated state. Then, ferrous chloride is precipitated by low-temperature crystallization, and the iron component is enriched by utilizing the difference in solubility of different components.

[0047] The second solid-liquid separation device 6 performs solid-liquid separation on the crystalline material, obtaining ferrous chloride crystals and a high-vanadium-content solution that meets the vanadium extraction standard, thus completing the separation of the iron component and the vanadium component.

[0048] The countercurrent washing device 7 and the hot air drying device 8 purify and dry the ferrous chloride crystals, and the material diversion device 9 diverts and reuses the treated crystals. The whole process adds crystallization and iron removal related processes and equipment to the original acid leaching vanadium extraction process without changing the original main process path. It can effectively reduce the ferrous ion content in the leaching solution and avoid the adverse effects of iron components on subsequent processes and the purity of vanadium products. The division of labor of each piece of equipment is clear and the process is connected in a coherent manner, which can stably realize the recycling and reuse of materials.

[0049] In this embodiment, the material outlet of the stirring leaching device 1 is connected to the feed end of the first solid-liquid separation device 2 via a closed conveying pipeline. The discharge end of the stirring and mixing device 3 is connected to the evaporation and concentration device 4. The discharge end of the evaporation and concentration device 4 is connected to the cooling and crystallization device 5. The discharge end of the cooling and crystallization device 5 is connected to the second solid-liquid separation device 6. The solid phase discharge end of the second solid-liquid separation device 6 is sequentially connected to the countercurrent washing device 7 and the hot air drying device 8. The discharge end of the hot air drying device 8 is connected to the material diversion device 9. The entire process sequentially executes steps S1, S2, S3, S4, and S5. Step S1 relies on the stirring leaching device 1 and the first solid-liquid separation device 2 to complete raw material leaching and solid-liquid separation. Step S2 relies on the stirring and mixing device 3 and the evaporation and concentration device 4 to complete crystal dissolution and solution concentration. Step S3 relies on the cooling and crystallization device 5 to complete ferrous chloride crystal precipitation. Step S4 relies on the second solid-liquid separation device 6 to complete solid-liquid separation. Step S5 relies on the countercurrent washing device 7, the hot air drying device 8, and the material diversion device 9 to complete crystal washing, drying, and diversion for reuse.

[0050] After the vanadium slag acid leaching operation is completed by the stirring leaching device 1, the material is directly conveyed to the first solid-liquid separation device 2 to complete the solid-liquid separation. The vanadium-iron leaching solution obtained by separation is sent to the stirring and mixing device 3 to add ferrous chloride crystals. The mixture is processed by the evaporation and concentration device 4 and the cooling and crystallization device 5 to form a solid-liquid suspension. Then, the second solid-liquid separation device 6 separates the ferrous chloride crystals and the high vanadium content solution. The ferrous chloride crystals are washed by the countercurrent washing device 7 and dried by the hot air drying device 8. After that, the material is distributed by the material diversion device 9. The equipment is connected in series to ensure that the processes from S1 to S5 are carried out continuously.

[0051] Specifically, the stirring leaching device 1 integrates a built-in constant temperature heat exchanger and multiple sets of axial stirring blades, and the pipeline is equipped with an anti-backflow baffle structure.

[0052] The built-in constant temperature heat exchanger can stabilize the temperature of the leaching system, and multiple sets of axial stirring blades form a full-area material disturbance flow field to ensure that the vanadium slag particles and acid solution are in continuous and sufficient contact, thereby improving the leaching effect. The anti-backflow baffle structure can block the reverse flow of materials and prevent the separated materials from flowing back into the stirring leaching device 1, ensuring that the leaching and solid-liquid separation operations in the S1 process operate independently and stably.

[0053] Furthermore, the stirring and mixing device 3 is equipped with a stepless speed-regulating stirring rod and an annular guide cavity, the evaporation and concentration device 4 is equipped with a vacuum generating component and an independent temperature control component, and a gas phase collection chamber is set at the top of the device.

[0054] The stepless speed-regulating stirring rod can adjust the stirring speed according to the state of the liquid. The annular guide cavity guides the material to circulate and prevents ferrous chloride crystals from depositing at the bottom of the stirring and mixing device 3, ensuring that the crystals are fully dissolved in the S2 process. The vacuum generating component creates a negative pressure environment inside the evaporation and concentration device 4 to lower the boiling point of the solution. The independent temperature control component maintains a stable temperature at the concentration station. The gas phase collection chamber can collect the condensate generated during the evaporation process, providing a water source for the water washing stage in the S5 process.

[0055] Furthermore, the cooling crystallization device 5 is equipped with a stirrer and an intelligent low-temperature controller. The rear end of the cooling crystallization device 5 is connected to an independent static crystal growth chamber, and a gentle slope material guiding structure is set at the bottom of the static crystal growth chamber.

[0056] The stirrer drives the solution to circulate continuously, preventing the solute from adhering and scaling on the inner wall of the cooling crystallization device 5. The intelligent low-temperature controller precisely maintains the low-temperature environment required for crystallization, ensuring the normal precipitation of ferrous chloride in the S3 process. The static crystal growth chamber provides a static environment for crystal growth, and the gentle slope material guide structure can smoothly transport materials and prevent crystal breakage.

[0057] Furthermore, the second solid-liquid separation device 6 is selected as either a centrifugal separation body or a filtration separation body. The centrifugal separation body is equipped with a radially layered flow guide chamber, and the filtration separation body is equipped with a multi-layer graded filter media assembly and a solid phase temporary storage chamber. The liquid phase outlet of both types of separation bodies is connected to a closed conveying pipeline.

[0058] The centrifugal separator relies on centrifugal force in conjunction with a radial stratification guide chamber to complete solid-liquid stratification and directional discharge of materials. The filtration separator uses multi-layer graded filter media components to progressively trap ferrous chloride crystals. The solid phase storage chamber temporarily stores solid materials. The sealed conveying pipeline can stably transport the high vanadium content solution to the next process, ensuring that the material conveying process of the S4 process is not disturbed by external factors.

[0059] Furthermore, the countercurrent washing device 7 is equipped with a double-pass flow chamber 71 and a spiral feeding assembly 72, and the hot air drying device 8 includes a hot air generating assembly 81 and a multi-layer mesh material support structure 82. The multi-layer mesh material support structure 82 is arranged in an alternating inclined manner. One end of the multi-layer mesh material support structure 82 is driven to vibrate by a vibration motor. The bottom of the hot air drying device 8 is provided with a hot air outlet, and the hot air outlet is connected to a return air duct. The return air duct is connected to the air inlet end of the hot air generating assembly 81.

[0060] The dual-pass flow chamber 71 enables reverse contact between the washing water and ferrous chloride crystals, while the spiral feeding assembly 72 pushes the crystals at a uniform speed, enhancing the washing effect of the S5 process. The hot air generating assembly 81 outputs a uniform hot airflow, and the staggered and inclined multi-layer mesh material support structure 82 forms a multi-pass inclined channel. The vibration motor drives the material support structure to vibrate, improving the uniformity of material drying. The return air duct realizes hot air circulation, improving the thermal energy utilization rate.

[0061] Furthermore, the first solid-liquid separation device 2 adopts a multi-stage stacked filtration structure, and the liquid phase collection chamber of the first solid-liquid separation device 2 is equipped with an online component detection component, which has a built-in ion sensing probe and a data transmission module.

[0062] The multi-stage stacked filtration structure progressively improves the interception accuracy, intercepting vanadium slag residues of different particle sizes in layers, thereby enhancing the solid-liquid separation effect of the S1 process. The ion sensing probe, in conjunction with the data transmission module, can detect the content of ferrous ions and vanadium pentoxide in the leachate in real time and transmit the data, providing a basis for adjusting the parameters of the S2 and S3 processes.

[0063] Furthermore, a mesh foam suppression component is installed inside the evaporation and concentration device 4, and an overall heat preservation and covering structure is set on the outside of the device. The gas phase collection chamber is connected to the countercurrent washing device 7 through a dedicated water supply pipeline.

[0064] The mesh foam suppression component can cut and break up the foam generated during the concentration process, preventing material loss with the gas phase. The overall heat insulation and covering structure reduces external heat exchange and stabilizes the concentration conditions of the S2 process. The dedicated water pipeline enables directional transportation of condensate, completing the closed-loop reuse of water resources.

[0065] Furthermore, the cooling crystallization device 5 is equipped with a fully enclosed heat-insulating enclosure structure on the outside, and a material buffer chamber is configured at the feed end of the device. The material buffer chamber is connected to the main body of the cooling crystallization device 5 through a smooth transition channel.

[0066] The fully enclosed thermal insulation structure reduces the impact of external temperature fluctuations on the crystallization system, the material buffer chamber slows down the feed flow rate, and the smooth transition channel avoids high-speed feed impact from damaging the precipitated crystals, thus ensuring the integrity of the crystallization product in the S3 process.

[0067] Furthermore, the material diversion device 9 is equipped with a diversion guide valve body and two independent discharge channels, which are respectively connected to the mixing device 3 and the chlorination process tail gas treatment station.

[0068] The diverting valve body can switch the material flow direction according to production needs. The two independent discharge channels realize the diversion and conveying of ferrous chloride crystals, respectively meeting the material needs of S2 process recycling and tail gas treatment, and realizing comprehensive utilization of materials.

[0069] In implementing the method for preparing qualified vanadium leachate from high-iron vanadium slag of the present invention, the equipment is first installed and deployed: according to the process flow, the stirring leaching device 1, the first solid-liquid separation device 2, the stirring and mixing device 3, the evaporation and concentration device 4, the cooling and crystallization device 5, the second solid-liquid separation device 6, the countercurrent washing device 7, the hot air drying device 8, and the material diversion device 9 are arranged in sequence; the conveying pipelines, water pipelines, and return air pipelines between each device are connected; the internal structure, transmission components, and temperature control components of each device are checked; and the installation and pipeline connection of the entire set of process equipment are completed.

[0070] After the equipment installation is completed, the whole machine debugging work is carried out: vanadium-removing slag and acid solution produced by titanium tetrachloride production are added to the stirring leaching device 1. The stirring leaching device 1, the first solid-liquid separation device 2, the stirring and mixing device 3, the evaporation and concentration device 4, the cooling and crystallization device 5, the second solid-liquid separation device 6, the countercurrent washing device 7, the hot air drying device 8, and the material diversion device 9 are started in sequence. The operating status of the constant temperature heat exchanger, stirring structure, vacuum component, low temperature controller, filter component, flow guiding structure, and vibration component are checked in sequence. It is confirmed that the data transmission of the online component detection component is normal, the pipeline conveying is smooth, and the formal production stage is entered after all equipment is debugged and correct.

[0071] Entering the formal production stage, the following process steps are executed sequentially: Step S1 involves adding the vanadium-removed slag from titanium tetrachloride production into an acid system. Stirring leaching is performed using device 1, where the acid dissolves the vanadium and iron components. After leaching, solid-liquid separation is achieved using device 2, resulting in a vanadium-iron leaching solution and solid leaching residue. The solid leaching residue is disposed of externally. Step S2 involves adding ferrous chloride crystals to the vanadium-iron leaching solution obtained in S1. The solution is then fed into a stirring and mixing device 3 to completely dissolve the crystals. The mixture is then transported to an evaporation and concentration device 4 for high-temperature evaporation and concentration, increasing the ferrous ion concentration in the system to achieve supersaturation of ferrous chloride, thus obtaining a high-iron-vanadium solution. Step S3 involves transporting the high-iron-vanadium solution from S2 to a cooling and crystallization device 5. Low-temperature temperature control causes the supersaturated ferrous chloride to precipitate crystals, completing the transformation of the iron component from the liquid phase to the solid phase. In step S4, the solid-liquid suspension formed in step S3 is introduced into the second solid-liquid separation device 6 for solid-liquid separation, yielding ferrous chloride crystals and a high-vanadium-content solution that meets the vanadium extraction standards. In step S5, the ferrous chloride crystals separated in step S4 are sequentially fed into a countercurrent washing device 7 and a hot air drying device 8 for washing and drying. The washing process uses condensate from the evaporation and concentration device 4 as the medium. The dried ferrous chloride crystals are distributed by the material distribution device 9, with one portion being returned to the stirring and mixing device 3 for recycling, and the other portion being sent to the chlorination process tail gas treatment step to prepare the ferrous chloride solution.

[0072] During the production process, the online component detection component of the first solid-liquid separation device 2 monitors the component content of the leachate in real time, the mesh foam suppression component and heat preservation structure of the evaporation and concentration device 4 maintain the stability of the concentration operation, and the heat preservation enclosure structure and material buffer chamber of the cooling crystallization device 5 ensure the crystallization effect. All equipment operates continuously and in coordination, and the whole process runs continuously and stably.

[0073] Once all batch production tasks are completed, the power, temperature control, vacuum, and transmission systems of all equipment are shut down in sequence, residual materials inside each piece of equipment are emptied, routine cleaning and maintenance of the equipment and pipelines are carried out, and the supporting pipelines and auxiliary components are organized. The entire equipment operation process is then completed.

[0074] Finally, it should be noted that the electronic components in the stirring leaching device 1, stirring and mixing device 3, etc. in this embodiment are all general standard parts or parts known to those skilled in the art. Their structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods. In the idle part of this device, all the above-mentioned electrical components are connected by wires. The specific connection method should refer to the working order between each electrical component in the above working principle to complete the electrical connection. All of these are technologies known in the art.

[0075] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing qualified vanadium leachate from high-iron-vanadium slag, characterized in that: The process includes the following steps performed sequentially: S1. The vanadium-removed slag produced by titanium tetrachloride production is put into the acid system and the stirring leaching device (1) is used to complete the stirring leaching operation. The vanadium and iron components are dissolved by the acid solution. After the leaching is completed, the first solid-liquid separation device (2) is used to separate the solid and liquid components to obtain vanadium-iron leaching solution and solid leaching slag. The solid leaching slag is disposed of externally. S2. Add ferrous chloride crystals to the vanadium-iron leaching solution obtained in S1 and send it to the stirring and mixing device (3) to achieve complete dissolution of the crystals. The mixture is then sent to the evaporation and concentration device (4) for high-temperature evaporation and concentration to increase the concentration of ferrous ions in the system so that ferrous chloride reaches a supersaturated state and a high iron-vanadium solution is obtained. This step utilizes the difference in solubility between ferrous chloride and vanadium compounds in the hydrochloric acid system to enrich the iron component. S3. The high iron-vanadium solution produced by S2 is transported to the cooling crystallization device (5). The supersaturated ferrous chloride crystals are precipitated by low temperature control, thus completing the transformation of the iron component from the liquid phase to the solid phase. S4. The solid-liquid suspension formed in S3 is introduced into the second solid-liquid separation device (6) to carry out solid-liquid separation, and ferrous chloride crystals and a high vanadium content solution that meets the vanadium extraction standard are obtained. S5. The ferrous chloride crystals separated from S4 are sequentially sent to the countercurrent washing device (7) and the hot air drying device (8) to complete the washing and drying. The washing uses the condensate generated by the evaporation and concentration device (4) as the medium. The dried ferrous chloride crystals are distributed by the material diversion device (9). One part is returned to the stirring and mixing device (3) for recycling, and the other part is sent to the chlorination process tail gas treatment process to prepare ferrous chloride solution, so as to realize the recycling of materials. This method adds a crystallization iron removal process to the original acid leaching vanadium extraction process without changing the original main process path. By crystallization separation, the ferrous ion content of the leaching solution is reduced, avoiding the adverse effects of iron components on the subsequent vanadium precipitation process and the purity of vanadium products.

2. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 1, characterized in that: The stirring leaching device (1) integrates a built-in constant temperature heat exchanger and multiple sets of axial stirring blades. The built-in constant temperature heat exchanger stabilizes the temperature of the leaching system through medium heat exchange. Multiple sets of axial stirring blades work together to form a full-area material disturbance flow field, ensuring that the vanadium slag particles and acid solution are in continuous and sufficient contact. The material outlet of the stirring leaching device (1) is connected to the feed end of the first solid-liquid separation device (2) through a closed conveying pipeline. The pipeline is equipped with an anti-backflow baffle structure to prevent the separated material from flowing back to the leaching station.

3. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 1, characterized in that: The stirring and mixing device (3) is equipped with a stepless speed-regulating stirring rod and an annular guide cavity. The stepless speed-regulating stirring rod can adjust the stirring speed to match different liquid states. The annular guide cavity guides the material to circulate and prevents ferrous chloride crystals from depositing on the bottom wall. The evaporation and concentration device (4) is equipped with a vacuum generating component and an independent temperature control component. The vacuum generating component forms a negative pressure environment inside the device to reduce the boiling point of the solution. The independent temperature control component adjusts and maintains the operating temperature of the concentration station in real time. A gas phase collection cavity is set at the top of the device to collect the condensate generated by evaporation.

4. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 1, characterized in that: The cooling crystallization device (5) is equipped with a stirrer and an intelligent low-temperature controller. The stirrer drives the solution to circulate continuously, preventing the solute from adhering and scaling on the inner wall of the cavity. The intelligent low-temperature controller accurately maintains the low-temperature environment required for crystallization. The rear end of the cooling crystallization device (5) is connected to an independent static crystal growth chamber. After the mixture of precipitated crystals enters the static crystal growth chamber, it maintains a static environment to allow ferrous chloride crystals to grow and form fully. The bottom of the static crystal growth chamber is equipped with a gentle slope material guiding structure to ensure that the material is transported out smoothly.

5. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 1, characterized in that: The second solid-liquid separation device (6) is a centrifugal separation body or a filtration separation body. The centrifugal separation body is equipped with a radial layered flow guide chamber. After the solid-liquid separation is completed by centrifugal force, the layered flow guide chamber guides the solid phase and liquid phase materials to be discharged in a directional manner. The filtration separation body is equipped with a multi-layer graded filter material assembly and a solid phase temporary storage chamber. The multi-layer graded filter material assembly intercepts ferrous chloride crystals step by step. The solid phase temporary storage chamber temporarily stores the filtered solid material. The liquid phase outlet of both types of separation bodies is connected to a closed conveying pipeline to transport the high vanadium content solution to the next process.

6. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 1, characterized in that: The washing device (7) is equipped with a double-pass flow chamber (71) and a spiral feeding assembly (72). The material enters from the head end of the double-pass flow chamber (71) and exits from the tail end. The washing water enters from the tail end of the double-pass flow chamber (71) and exits from the head end. The double-pass flow chamber (71) achieves reverse contact between the washing water and the ferrous chloride crystals. The spiral feeding assembly (72) pushes the crystals to move at a uniform speed and enhances the washing contact effect. The hot air drying device (8) includes a hot air generating assembly (81) and a multi-layer mesh support structure (82). The hot air generating assembly (81) 1) Output uniform hot airflow, multi-layer mesh support structure (82) supports crystals and allows hot air to penetrate the material layer, improving the overall dehydration efficiency. The multi-layer mesh support structure (82) is arranged in an alternating inclined manner, forming a multi-stroke inclined channel inside the hot air drying device (8). One end of the multi-layer mesh support structure (82) is driven by a vibration motor to vibrate. The bottom of the hot air drying device (8) is provided with a hot air outlet. The hot air outlet is connected to a return air pipe. The return air pipe is connected to the air inlet of the hot air generating component (81) to realize hot air circulation.

7. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 2, characterized in that: The first solid-liquid separation device (2) adopts a multi-stage stacked filtration structure. The interception accuracy of each filtration unit is improved step by step, and it can intercept vanadium slag residues of different particle sizes in layers. The liquid phase collection chamber of the first solid-liquid separation device (2) is equipped with an online component detection component. The online component detection component has a built-in ion sensing probe and data transmission module to detect the content of ferrous ions and vanadium pentoxide in the leachate in real time and transmit the detection data to the outside.

8. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 3, characterized in that: The evaporation and concentration device (4) is equipped with a mesh foam suppression component inside. The mesh foam suppression component cuts and breaks the foam generated during the concentration process to prevent the material from being lost with the gas phase. The device is equipped with an overall heat insulation and covering structure on the outside to reduce heat exchange with the external environment and ensure stable concentration conditions. The gas phase collection chamber is connected to the countercurrent washing device (7) through a dedicated water supply pipeline to realize closed-loop reuse of condensate.

9. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 4, characterized in that: The cooling crystallization device (5) is equipped with a fully enclosed heat-insulating enclosure structure on the outside to reduce the influence of external temperature fluctuations on the internal crystallization system. The feed end of the device is equipped with a material buffer chamber, which slows down the feed flow rate and avoids high-speed feed impact from damaging the precipitated crystal structure. The material buffer chamber is connected to the main body of the cooling crystallization device (5) through a smooth transition channel.

10. The method for preparing qualified vanadium leachate from high-iron-vanadium slag according to claim 6, characterized in that: The material diversion device (9) is equipped with a diversion valve body and two independent discharge channels. The diversion valve body switches the material flow direction according to production needs. The two independent discharge channels are respectively connected to the mixing device (3) and the chlorination process tail gas treatment station.

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