Molten salt chlorination furnace water quenching pulping system and method

Abstract

The invention relates to the technical field of design and manufacturing of metallurgical production equipment, in particular to a molten salt chlorination furnace water quenching pulping system and method. The molten salt chlorination furnace water quenching pulping system comprises a salt receiving chute, a slag flushing tank, a water quenching pulping pool, a filter and a salt water pool which are connected in sequence. A slurry conveying pump and a circulating slag flushing pump are arranged at an outlet of the water quenching pulping pool, the slurry conveying pump is communicated with the filter through a conveying pipeline, the circulating slag flushing pump is communicated with an inlet of the water quenching pulping pool through a circulating pipeline, and a heat exchanger is arranged on the circulating pipeline. According to the water-quenching pulping system and method for the molten salt chlorination furnace, water-quenching pulping of the high-temperature molten salt chlorination waste salt slag can be achieved, the cooling problem of the high-temperature molten salt chlorination waste salt slag is effectively solved, and meanwhile a foundation is laid for the process of further separating recyclable components in the molten salt chlorination waste salt slag.

Description

Technical Field

[0001] This invention relates to the field of metallurgical production equipment design and manufacturing technology, specifically to a molten salt chlorination furnace water quenching and pulping system and method. Background Technology

[0002] The main raw material for domestic sponge titanium and titanium dioxide production is TiCl4, and TiCl4 production mainly employs molten salt chlorination and fluidized bed chlorination processes. For titanium slag raw materials with W(Ca+Mg) > 5%, the most suitable process is currently molten salt chlorination. Molten salt chlorination generates a large amount of NaCl-containing waste residue (referred to as waste salt), which is currently commonly stored using stockpiling. However, this waste residue may contain other toxic or harmful substances. If stockpiled without proper treatment, it may pollute soil, water sources, and the ecological environment. Although NaCl itself has relatively low direct environmental toxicity, large-scale stockpiling can lead to soil salinization, affecting crop growth. Furthermore, improper stockpiling of waste residue can cause other environmental problems, such as occupying large amounts of land and generating harmful gas emissions. Simultaneously, substances in this waste residue may undergo chemical reactions during long-term stockpiling, producing new pollutants or harmful substances, further exacerbating environmental risks.

[0003] Therefore, NaCl-containing waste residue generated from molten salt chlorination processes must be treated scientifically and rationally, such as through harmless treatment and resource utilization, to minimize its environmental harm. Water quenching and pulping of the molten salt chlorination waste residue is an effective way to address both the comprehensive utilization of waste salt and environmental protection issues.

[0004] Patent application CN118684265A proposes a method for recovering Ti from quenched slag in chlorinated waste salt water. This method focuses on recovering Ti and C resources from chlorinated waste salt slag, achieving component separation through processes such as acid washing, aeration cyclone separation, and membrane filtration. However, because the temperature of molten salt chlorinated waste slag reaches as high as 700-750℃, direct discharge is prone to solidification and corrosion of equipment, and may release harmful gases (such as HCl). Therefore, the existing technology still needs improvement. Summary of the Invention

[0005] In view of this, the present invention proposes a water-quenched pulping system and method for molten salt chlorination furnace, which can realize water quenching and pulping of high-temperature molten salt chlorination waste salt residue. This not only more effectively solves the cooling problem of high-temperature molten salt chlorination waste salt residue, but also lays the foundation for further separation of recyclable components from molten salt chlorination waste salt residue.

[0006] The molten salt chlorination furnace water quenching and slurry making system proposed in the first aspect of the present invention includes a salt receiving chute, a slag flushing trough, a water quenching and slurry making tank, a filter, and a brine tank connected in sequence. A slurry delivery pump and a circulating slag flushing pump are installed at the outlet of the water quenching and slurry making tank. The slurry delivery pump is connected to the filter via a delivery pipeline, and the circulating slag flushing pump is connected to the inlet of the water quenching and slurry making tank via a circulation pipeline. A heat exchanger is installed on the circulation pipeline.

[0007] In some embodiments, the salt receiving chute includes two rectangular tanks equipped with stirring devices. Each rectangular tank is equipped with a slurry delivery pump and a circulating slag flushing pump at its outlet. The slag flushing chute has two outlets, each of which is connected to a corresponding rectangular tank via a slurry pipe. The two outlets and the slurry pipes are configured in a one-in-one standby mode.

[0008] In some embodiments, the inner wall of the pulping pipe is provided with a corrosion-resistant ceramic layer.

[0009] In some embodiments, a first return pipe is also provided between the circulating slag flushing pump and the inlet of the slag flushing trough.

[0010] In some embodiments, a second return pipe is provided between the outlet of the heat exchanger and the inlet of the slag flushing tank.

[0011] In some embodiments, the top of the salt chute is provided with a cover plate, which is a hinged, openable and closable structure.

[0012] In some embodiments, the filter is a plate and frame type with a pore size ≤50μm, and the filtrate brine is reused for replenishing the slag flushing tank.

[0013] In some embodiments, two brine tanks are provided, each equipped with a brine transfer pump. The outlet of the brine transfer pump is divided into two paths: one path connects to the inlet of the slag flushing tank, and the other path connects to the subsequent process.

[0014] In some embodiments, the stirring device in the water-quenching pulping tank rotates at 100~300 rpm, and the aeration rate is 0.5~1.5 m³ / s. 3 / min.

[0015] A second aspect of the present invention provides a method for water-quenching and pulping in a molten salt chlorination furnace, which is implemented based on the water-quenching and pulping system of the molten salt chlorination furnace described in any of the above embodiments, and includes the following steps: High-temperature molten salt chlorination waste residue is introduced into a slag flushing tank via a salt receiving chute for water quenching and slag flushing. The generated water-quenched slag enters the water-quenched pulping tank through the pulping pipe for pulping and aeration to form slurry; If the slurry temperature exceeds 100℃, the slurry is transported to a heat exchanger for heat exchange and cooling via a circulating slag flushing pump. The slurry cooled by the heat exchanger is then transported back to the water-quenched slurry tank. Otherwise, the slurry is pumped into a filter for filtration, concentration, and separation. The filtrate produced after separation can be buffered in a brine tank or reused in the slag flushing tank, while the generated mud is transported off-site for disposal.

[0016] The beneficial effects of this application are as follows: This application sets up a salt receiving chute, a slag flushing chute, a water-quenched slurry tank, a filter, and a brine tank connected in sequence. A slurry delivery pump and a circulating slag flushing pump are installed at the outlet of the water-quenched slurry tank. The slurry delivery pump is connected to the filter via a delivery pipeline, and the circulating slag flushing pump is connected to the inlet of the water-quenched slurry tank via a circulation pipeline. A heat exchanger is installed on the circulation pipeline. If the slurry temperature in the water-quenched slurry tank is still high (e.g., exceeding 100℃), part of the slurry can be cooled by heat exchanger and then returned to the inlet of the water-quenched slurry tank, forming a circulation process. This ensures stable operation of the system at a suitable temperature and improves cooling efficiency. The slurry that has reached a suitable temperature enters the filter for filtration, concentration, and separation. The filtrate produced after filtration can be buffered in the brine tank or reused in the slag flushing chute, while the generated slurry is transported off-site for disposal. This system, through modular design and coordinated control, effectively solves the problems of instant cooling, continuous treatment, and resource recovery of high-temperature molten salt waste, and has advantages such as high processing efficiency, stable operation, and low energy consumption. This also lays the foundation for further processes to separate recyclable components from molten salt chlorination waste salt residue. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other embodiments can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of a molten salt chlorination furnace water quenching and pulping system provided in one embodiment of the present invention; Figure 2 This is a flowchart of a molten salt chlorination furnace water quenching and pulping method provided in one embodiment of the present invention.

[0019] Explanation of reference numerals in the attached figures: 1. Salt chute; 2. Slag flushing chute; 3. Pulping pipe; 4. Water quenching pulverizing tank; 5. Mixing device; 6. Pulp delivery pump; 7. Circulating slag flushing pump; 8. Heat exchanger; 9. Filter; 10. Brine tank; 11. Brine delivery pump. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0021] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0022] The present invention proposes a molten salt chlorination furnace water quenching and pulping system, such as Figure 1 As shown, the system includes a salt receiving chute 1, a slag flushing chute 2, a water-quenched pulping tank 4, a filter 8, and a brine tank 9, connected in sequence. The outlet of the water-quenched pulping tank 4 is equipped with a slurry delivery pump 5 and a circulating slag flushing pump 6. The slurry delivery pump 5 is connected to the filter 8 via a delivery pipeline to transport the slurry to the filter 8 for filtration, concentration, and separation. The circulating slag flushing pump 6 is connected to the inlet of the water-quenched pulping tank 4 via a circulation pipeline. A heat exchanger 7 is installed on the circulation pipeline. High-temperature molten salt chlorination waste salt slag enters the slag flushing chute 2 through the salt receiving chute 1 for thorough dispersion and significant cooling before entering the water-quenched pulping tank 4 for thorough pulping and aeration. A temperature detector is installed in the water-quenched pulping tank 4 to monitor the slurry temperature. If the slurry temperature in the water-quenched pulping tank 4 remains high (e.g., exceeding 100℃), a portion of the slurry can be returned to the inlet of the water-quenched pulping tank 4, forming a circulating process. The heat exchanger 7 on the circulating pipeline can forcibly cool the return slurry, ensuring stable operation of the system at a suitable temperature. The slurry, having reached the appropriate temperature, is filtered and concentrated by filter 8. The resulting brine is sent to the brine tank 9, while the generated slurry is sent for pressure filtration. Through modular design and coordinated control, this system effectively solves the problems of instant cooling, continuous treatment, and resource recovery of high-temperature molten salt waste, offering advantages such as high processing efficiency, stable operation, and low energy consumption.

[0023] In some embodiments, the water-quenched slurry tank 4 includes two rectangular tanks equipped with stirring devices 41, which are arranged in parallel. Each rectangular tank can be equipped with multiple stirring devices 41. Specifically, the stirring devices 41 can be paddle mixers, turbine mixers, or anchor-frame combined mixers, etc. Several stirring devices 41 are evenly spaced at the bottom of the rectangular tanks to ensure uniform dispersion and initial cooling of the high-temperature molten salt slag, promote thorough crushing of the slag, and prevent sedimentation. Each rectangular tank outlet is equipped with a slurry delivery pump 5 and a circulating slag flushing pump 6. The slag flushing trough 2 has dual outlets, each connected to a corresponding rectangular tank via a slurry pipe 3. The dual outlets and slurry pipe 3 operate in a one-in-one-outstand mode. When one pipe is under maintenance or blocked, the system can be immediately switched to the standby pipe to ensure continuous system operation. This parallel design of the two tanks enables a doubling of processing capacity and mutual backup, significantly improving operational reliability, greatly increasing processing efficiency while ensuring safe production, and reducing maintenance costs.

[0024] In some embodiments, the inner wall of the slurry pipe 3 is provided with a corrosion-resistant ceramic layer. The ceramic layer (such as alumina or silicon carbide) can effectively resist the corrosion of chloride ions and acidic substances in high-temperature molten salt waste, enabling the pipe to still be used under harsh conditions such as pH 1~12 and temperature ≤200℃. Secondly, the ceramic surface has a smoothness of Ra≤0.2μm, which can significantly reduce the flow resistance of the slurry, improve the pipeline transportation efficiency, and prevent slag particles from adhering and scaling. It is particularly suitable for the high corrosion and high wear characteristics of molten salt chlorination waste, ensuring the long-term stable operation of the system.

[0025] In some embodiments, a first return pipe is also provided between the inlet of the circulating slag flushing pump 6 and the slag flushing tank 2, and a one-way control valve is installed on the first return pipe. This first return pipe forms a forced circulation loop, which can re-inject a portion of the cooled slurry into the slag flushing tank 2, so that the temperature in the slag flushing tank 2 is stably controlled within the ideal range of 60~90℃, avoiding thermal stress damage to the equipment caused by high temperature. At the same time, the high-speed impact energy of the return slurry enhances the secondary crushing of the waste residue, reducing the median particle size of the residue. In addition, the closed-loop circulation design can also reduce the consumption of fresh water, and with the heat exchanger 7, the system's thermal energy consumption can be reduced. It is particularly suitable for processing molten salt waste residue with large temperature fluctuations, significantly extending the service life of the slag flushing tank 2 and the pipe while improving crushing efficiency.

[0026] In some embodiments, a second reflux pipe is provided between the outlet of heat exchanger 7 and the inlet of slag flushing tank 2. This second reflux pipe precisely reinjects temperature-regulating slurry at 60~80℃ at a flow rate of 4~6m / s, forming a controllable heat exchange with the molten waste slag at 700℃ or higher. The "gradient cooling" technology induces directional thermal stress cracks within the waste slag, improving crushing efficiency and ensuring that the slag particle D90 is stably controlled below 180μm. This design increases the system's processing capacity while reducing energy consumption, making it particularly suitable for the industrial continuous processing of high-temperature molten salt waste slag containing complex components (such as those containing Ca, Fe, Mg, Mn, Ti, etc.).

[0027] In some embodiments, the salt chute 1 is inclined, with a larger upper port diameter and a smaller lower port diameter. A cover plate is provided on the top of the salt chute 1, and the cover plate is a hinged, openable and closable structure. The cover plate is made of high-temperature resistant stainless steel (such as 310S), which can completely seal the tank when closed, reducing the amount of harmful gases (such as HCl, Cl2) emitted. Combined with a negative pressure exhaust system, it enables the operating environment to meet industrial hygiene standards.

[0028] In some embodiments, the filter 8 is a plate and frame type with a pore size ≤50μm. Under a working pressure of 2.0MPa, it can efficiently trap most suspended particles, producing a clear brine filtrate with a turbidity ≤10NTU. The generated brine filtrate can be reused as makeup water for the sludge flushing tank 2 or sent to the brine tank 9. The resulting slurry is sent for pressure filtration. Preferably, two filters 8 can be configured, one as a backup, to improve system reliability.

[0029] In some embodiments, two brine tanks 9 are provided, each equipped with a brine transfer pump 10. The outlet of the brine transfer pump 10 is divided into two paths: one connects to the inlet of the slag flushing tank 2, and the other connects to subsequent processes. In this embodiment, the two brine tanks 9 operate in an alternating mode, achieving seamless switching through an intelligent liquid level control system to ensure improved continuous system operation. The variable frequency brine transfer pump 10 equipped in each tank can precisely control the diversion ratio, with 30-70% of the brine being recycled to the slag flushing tank 2 after online pH / temperature adjustment to improve the stability of the water quenching conditions. The remaining brine is transported to the evaporation and crystallization process after nano-level filtration.

[0030] In some embodiments, the stirring device 41 in the water-quenched pulping tank 4 rotates at a speed of 100~300 rpm, and the aeration rate is 0.5~1.5 m³ / s. 3 / min. In this embodiment, the water quenching and pulping tank 4 uses a variable frequency speed-regulating agitator at 100~300rpm, combined with a stirring speed of 0.5~1.5m. 3The adjustable aeration rate ( / min) of the synergistic design improves the waste residue crushing efficiency, with the average particle size stably controlled between 80 and 120 μm. Simultaneously, the microbubbles generated by aeration effectively prevent solid deposition, making it particularly suitable for high-salt waste residues containing high levels of impurities such as Ca, Fe, and Mn (Cl...). - Treatment with ≤200g / L of hazardous waste can achieve the harmless treatment of hazardous waste while improving the purity of subsequent recyclable metal resources.

[0031] The second aspect of this invention provides a method for water quenching and pulping in a molten salt chlorination furnace, implemented based on the water quenching and pulping system for a molten salt chlorination furnace described in any of the above embodiments, such as... Figure 2 As shown, it includes the following steps: The high-temperature molten salt chlorination waste residue (700~750℃) is buffered by the salt receiving chute 1 and then introduced into the slag flushing tank 2 for water quenching and slag flushing. The generated water-quenched slag enters the water-quenched pulping tank 4 through pulping pipe 3 for pulping and aeration to form slurry; If the slurry temperature exceeds the predetermined temperature (e.g., 100°C), the slurry is transported to the heat exchanger 7 via the circulating slag flushing pump 6 for heat exchange and cooling, and the slurry cooled by the heat exchanger 7 is transported back to the water-quenched slurry tank 4 for slurrying and aeration; otherwise, the slurry is pumped into the filter 8 via the slurry transport pump 5 for filtration, concentration and separation, and the filtrate generated after separation by the filter 8 can be buffered or reused in the slag flushing tank 2 via the brine tank (9), and the generated mud is transported off-site for disposal.

[0032] This application improves system thermal efficiency and extends equipment life through multi-stage temperature control. Furthermore, the closed-loop water circulation design enables energy-efficient wastewater discharge and reduces the cost per ton of slag treatment. It is particularly suitable for enterprises both domestically and internationally that use the molten salt chlorination process to produce titanium tetrachloride, and for the resource recovery of titanium slag raw materials containing high levels of Ca and Mg, to achieve high-temperature molten salt chlorination waste residue. This significantly improves subsequent metal recovery rates and the purity of by-product industrial salt.

[0033] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0034] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A molten salt chlorination furnace water quenching and pulping system, characterized in that, include: A salt chute (1), a slag flushing chute (2), a water quenching and pulping tank (4), a filter (8), and a brine tank (9) are connected in sequence; wherein a slurry conveying pump (5) and a circulating slag flushing pump (6) are provided at the outlet of the water quenching and pulping tank (4), the slurry conveying pump (5) is connected to the filter (8) through a conveying pipeline, and the circulating slag flushing pump (6) is connected to the inlet of the water quenching and pulping tank (4) through a circulating pipeline, and a heat exchanger (7) is provided on the circulating pipeline.

2. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, The water-quenched slurry tank (4) includes two rectangular tanks with stirring devices (41). Each rectangular tank is equipped with a slurry delivery pump (5) and a circulating slag flushing pump (6) at its outlet. The slag flushing tank (2) is equipped with two outlets. Each outlet is connected to a rectangular tank through a slurry pipe (3). The two outlets and the slurry pipe (3) are in a one-in-one-out standby mode.

3. The molten salt chlorination furnace water quenching and pulping system according to claim 2, characterized in that, The inner wall of the slurry pipe (3) is provided with a corrosion-resistant ceramic layer.

4. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, A first return pipe is also provided between the inlet of the circulating slag flushing pump (6) and the slag flushing tank (2).

5. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, A second return pipe is also provided between the outlet of the heat exchanger (7) and the inlet of the slag flushing tank (2).

6. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, The top of the salt receiving chute (1) is provided with a cover plate, which is a hinged, openable and closable structure.

7. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, The filter (8) is a plate and frame type with a filter pore size ≤50μm. The brine from the filtrate is reused to replenish the slag flushing tank (2).

8. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, Two brine tanks (9) are provided, and each brine tank (9) is equipped with a brine transfer pump (10). The outlet of the brine transfer pump (10) is divided into two paths, one of which is connected to the inlet of the slag flushing tank (2), and the other is connected to the subsequent process.

9. The molten salt chlorination furnace water quenching and pulping system according to claim 1, characterized in that, The stirring device (41) in the water-quenched pulping tank (4) rotates at a speed of 100~300 rpm and has an aeration rate of 0.5~1.5 m³ / s. 3 / min.

10. A method for water quenching and pulping in a molten salt chlorination furnace, characterized in that, The implementation of the molten salt chlorination furnace water quenching and pulping system according to any one of claims 1 to 9 includes the following steps: The high-temperature molten salt chlorination waste residue is introduced into the slag flushing tank (2) via the salt receiving chute (1) for water quenching and slag flushing; The generated water-quenched slag is introduced into the water-quenched pulping tank (4) through the pulping pipe (3) for pulping and aeration to form slurry; If the slurry temperature exceeds the predetermined temperature, the slurry is transported to the heat exchanger (7) via the circulating slag flushing pump (6) for heat exchange and cooling, and the slurry cooled by the heat exchanger (7) is transported back to the water-quenched slurry tank (4); otherwise, the slurry is pumped into the filter (8) by the slurry transport pump (5) for filtration, concentration and separation, and the filtrate generated after separation by the filter (8) is buffered in the brine tank (9) or reused in the slag flushing tank (2), and the generated mud is transported off-site for disposal.

Images