A fixed station type copper residue temperature control crystallization waste heat recovery method

Abstract

The application provides a fixed station type copper slag temperature control crystallization waste heat recovery method, and belongs to the technical field of non-ferrous metallurgical slag treatment, which comprises the following steps: hoisting a hoistable slag pot containing copper slag into a fixed slag pot cover, covering the slag pot cover, and inserting a heat exchange component into the copper slag through the slag pot cover; introducing deoxidized water into the waste heat recovery component to absorb the heat transferred by the outer wall of the hoistable slag pot, generating a steam-water mixture which is separated by a steam drum, and delivering steam to a steam output system; introducing a heat exchange medium into the heat exchange component to perform heat exchange and temperature field adjustment on the inside of the copper slag; controlling the medium flow, pressure and operation stage of the two components in stages through a control system, so that the copper slag is cooled, crystallized and controlled, and waste heat is recovered according to the set cooling curve; when the copper slag reaches the target pot temperature or completes the set temperature control process, the heat exchange component is pulled out, the slag pot cover is lifted, and the slag pot is hoisted out. The scheme constructs an internal and external cooperative heat exchange system, improves the operation safety and reliability.

Description

Technical Field

[0001] This application relates to the field of non-ferrous metallurgical slag treatment technology, and in particular to a fixed-station method for recovering waste heat from copper slag temperature-controlled crystallization. Background Technology

[0002] Copper smelting produces a large amount of high-temperature copper slag. When discharged, the copper slag is at a high temperature, contains a significant amount of sensible heat, and also contains iron-silicon oxide systems, copper matte phase, small amounts of metallic copper or copper matte inclusions, and other valuable components. In current production, high-temperature copper slag is often discharged into slag pots, slag ladles, or slag basins, and then processed through natural cooling, stockpiling, crushing, flotation, magnetic separation, return to the furnace, or conversion into building materials.

[0003] Natural cooling of slag pots typically suffers from problems such as uncontrollable temperature field, large temperature difference between the inside and outside of the slag, long turnover cycle, and significant sensible heat loss. If cooling is too rapid, it can lead to fine dispersion of the recyclable phase; if cooling is too slow, it reduces the turnover efficiency of the slag pot and increases space occupation. Ordinary slag pots primarily serve the functions of holding, transferring, and dumping, and generally lack the ability to actively regulate the temperature field.

[0004] Most publicly available slag waste heat recovery technologies primarily utilize stationary waste heat boilers, fluidized bed heat exchangers, rotary drum heat exchangers, granulation waste heat recovery, or water-cooled wall heat exchangers. Directly installing boiler piping onto the mobile slag pot would result in a complex slag pot structure, difficulties in hoisting, frequent water-steam interface connections, increased difficulty in moving steam pipelines with the vehicle, and greater challenges in inspection and maintenance.

[0005] Coupled high-temperature molten slag with water or steam systems, safety requirements also exist. If liquid water directly enters the internal pipes that undergo intense heat exchange with the high-temperature molten slag, damage to the pipe wall, localized and violent vaporization, poor steam exhaust, or abnormal pressure could lead to thermal shock, overpressure, splashing, or equipment damage. Therefore, a fixed-station treatment system suitable for high-temperature copper slag in copper smelting is needed. Summary of the Invention

[0006] In view of this, the present application provides a fixed-station copper slag temperature-controlled crystallization waste heat recovery method, which at least partially solves the problems in the prior art such as uncontrollable natural cooling temperature field of copper slag pots, waste of sensible heat, long turnover cycle of slag pots, difficulty in safely coupling the waste heat recovery system with the mobile slag pot, and water vapor safety risks in the internal heat exchange of high-temperature molten slag.

[0007] This application provides a fixed-station copper slag temperature-controlled crystallization waste heat recovery method, based on a fixed-station copper slag temperature-controlled crystallization waste heat recovery system. The system includes a hoisting slag pot for receiving copper smelting slag, a fixed slag pot outer casing for housing the hoisting slag pot, a waste heat recovery component disposed within the fixed slag pot outer casing and exchanging heat with the hoisting slag pot, a heat exchange component inserted into the copper slag for heat exchange, a steam drum for steam-water separation, and a control system. The method includes the following steps:

[0008] Step 1: Hoist the transportable slag pot containing copper smelting slag into the outer casing of the fixed slag pot. The loading temperature of the copper smelting slag is 600℃ to 1500℃. Step 2: Cover the top of the slag pot with the slag pot lid, slide the heat exchange component to the slag pot lid, and insert it into the copper slag through the slag pot lid; Step 3: Pass deoxygenated water into the waste heat recovery component to absorb the heat transferred from the outer wall of the hoistable slag tank and generate a steam-water mixture. The steam-water mixture is separated by a steam drum, and the separated steam is sent to the steam output system. Step 4: Introduce heat exchange medium into the heat exchange assembly to exchange heat and regulate the temperature field inside the copper slag; Step 5: The control system adjusts the medium flow rate, pressure and operating stage of the waste heat recovery component and / or heat exchange component in stages according to the temperature of the copper slag, so that the copper slag is cooled by temperature control, crystallization regulation and waste heat recovery according to the set cooling curve. Step 6: When the copper slag reaches the target discharge temperature or completes the set temperature control process, remove the heat exchange component, lift the slag pot cover, and lift the hoistable slag pot out of the fixed slag pot outer casing.

[0009] According to a specific implementation of the present application, in step 3, the steam-water mixture generated by the waste heat recovery component is separated by steam-water separation in the steam drum, and the separated steam enters the steam output system for output; or, the separated steam enters the heat exchange component and further absorbs heat inside the copper slag to increase the steam dryness or temperature.

[0010] According to a specific implementation of an embodiment of this application, in step 4, the method of introducing the heat exchange medium is switched based on a first set temperature, including: when the temperature of the copper slag is higher than the first set temperature, steam or inert gas is introduced into the heat exchange component, and liquid water is prohibited from entering the heat exchange component; when the temperature of the copper slag is lower than the first set temperature and the safety interlock conditions of the pressure, temperature, position, steam drum water level and slag pot cover status of the heat exchange component are met, deoxygenated water, steam-water mixture or low-temperature steam is allowed to be introduced into the heat exchange component, wherein the first set temperature is 500°C to 800°C.

[0011] According to a specific implementation of an embodiment of this application, the security interlocking conditions include: When the slag container is not seated in the fixed slag container outer casing, the slag container lid must not be lowered; The heat exchange components must not be lowered if the slag tank cover is not in place. When the heat exchange components are not in place, it is forbidden to introduce heat exchange medium into the heat exchange components; When the temperature of the copper slag is higher than the first set temperature, liquid water is prohibited from entering the heat exchange components; If the steam drum water level, pressure, or safety valve is abnormal, the system must not be operated under increased load. Lifting the slag tank lid is prohibited until the heat exchange components are fully removed.

[0012] According to a specific implementation of an embodiment of this application, the step of pulling out the heat exchange component includes: Stop the flow of liquid water into the heat exchange component and switch to steam or inert gas to purge the inside of the heat exchange component to reduce the residual moisture and pressure inside the heat exchange component. Keep the slag pot lid covering the top of the hoistable slag pot, and slowly raise the heat exchange components relative to the slag pot lid; The control system monitors the position and upward resistance of the heat exchange components. Once it is confirmed that the heat exchange components have completely detached from the copper slag and entered a safe position, the slag pot cover is allowed to be lifted and hoisted.

[0013] According to a specific implementation of an embodiment of this application, the slag pot cover is lifted and transported via a foldable gantry mechanism and a lifting mechanism, wherein allowing the slag pot cover to be lifted and transported includes: After the slag pot lid is lifted to a high position by the lifting mechanism, the foldable gantry mechanism folds it to the clearance position; After the control system confirms that the foldable gantry mechanism has made proper clearance, the overhead crane is allowed to lift out the slag hopper.

[0014] According to a specific implementation of an embodiment of this application, the step of adjusting the medium flow rate, pressure, and operating stage of the waste heat recovery component and / or heat exchange component in stages according to the copper slag temperature by a control system includes: The control system has multiple preset cooling curves, each corresponding to a different target outlet temperature of copper slag or different downstream process requirements. The control system calls up the corresponding set cooling curve according to the needs of subsequent processes such as copper slag return to furnace, crushing, flotation, magnetic separation, storage or transfer; Based on the temperature-time relationship contained in the set cooling curve, the flow rate and pressure of the medium in the waste heat recovery component and / or heat exchange component are adjusted in stages. Each set cooling curve includes an effective crystallization window for the copper matte phase, which is 900℃~970℃. The cooling rate within the window is 5℃ / h~50℃ / h, and the dwell time within the window is 1 hour~6 hours.

[0015] According to a specific implementation of an embodiment of this application, the method further includes: The control system dynamically adjusts the flow rate of the medium in the waste heat recovery component and the heat exchange component based on the difference between the real-time temperature of the copper slag and the target temperature of the set cooling curve at the same time point, using a PID control algorithm. Specifically, this includes: When the real-time temperature of the copper slag is higher than the target temperature of the set cooling curve, the medium flow rate is increased to enhance heat exchange; when the real-time temperature of the copper slag is lower than the target temperature of the set cooling curve, the medium flow rate is reduced to weaken heat exchange; the control system collects temperature data inside and outside the copper slag in real time through temperature sensors to form a closed-loop feedback control.

[0016] According to a specific implementation of an embodiment of this application, the phased adjustment operation of the control system includes at least the following: During the high-temperature rapid cooling stage, when the temperature of the copper slag is higher than the second set temperature, the waste heat recovery component operates at the first medium flow rate, and the heat exchange component is introduced with steam or inert gas and operates at the second medium flow rate. During the medium-temperature slow cooling stage, when the temperature of the copper slag is between the third set temperature and the second set temperature, the waste heat recovery component operates with the third medium flow rate, and the heat exchange component is circulated with deoxygenated water or a steam-water mixture and operates with the fourth medium flow rate. During the low-temperature slow cooling stage, when the temperature of the copper slag is lower than the third set temperature, the waste heat recovery component operates at the fifth medium flow rate and the heat exchange component operates at the sixth medium flow rate. The second set temperature is higher than the third set temperature, and the medium flow rate at each stage is set and adjusted by the control system according to the temperature gradient of the set cooling curve.

[0017] According to a specific implementation of this application, the target discharge temperature is set according to the needs of subsequent processes such as copper slag return to furnace, crushing, flotation, magnetic separation, storage or transfer, and the target discharge temperature is 100℃ to 900℃.

[0018] Beneficial effects: The fixed-station copper slag temperature-controlled crystallization waste heat recovery method in this application embodiment has the following beneficial effects: 1. By fixing the waste heat recovery components inside the fixed slag pot outer shell, the hoisting slag pot body does not need to integrate any pressure heat exchange pipelines and water vapor accessories. The heat exchange medium pipeline does not move with the slag pot, which fundamentally eliminates the risks of heat exchange pipeline interface leakage, operation interference and operation and maintenance safety in the existing technology. The slag pot has a simple structure and is easy to turn around, which significantly improves the operation and maintenance safety of the smelting site.

[0019] 2. By indirectly exchanging heat through the outer wall of the waste heat recovery component and directly exchanging heat through the interior of the heat exchange component, an internal and external synergistic heat exchange system is formed. The control system performs phased linkage adjustment of the flow rate, pressure and operation stage of the two heat exchange media, so that the copper slag cooling process can be actively controlled according to the set cooling curve. This achieves controlled cooling and crystallization regulation of copper slag, overcoming the defects of existing technologies such as uncontrollable temperature field, large temperature difference between the inside and outside of the slag, inability to adjust the cooling rate of copper slag, and uncontrollable crystallization process of valuable minerals. This effectively improves the separation efficiency of subsequent flotation, magnetic separation and other processes.

[0020] 3. By using the first set temperature as a criterion to switch the medium introduced into the heat exchange component in stages, liquid water is prohibited from entering the tube heat exchanger and only steam or inert gas is introduced. In the low temperature stage, deoxygenated water or steam-water mixture is allowed to be introduced only after the safety interlock conditions are met. This effectively prevents the safety accident of boiling over caused by high temperature molten slag encountering liquid water and ensures the inherent safety of the internal heat exchange process.

[0021] 4. By establishing a complete sequence of safety interlocking control chains from slag pot seating to hoisting out, covering the entire process of slag pot seating confirmation, slag pot cover positioning, heat exchange component positioning, medium inlet permission, steam drum status monitoring, pipe removal confirmation, and cover lifting permission, the safety and reliability of the action sequence between high-temperature molten slag, water-steam system, heat exchange components, and slag pot cover are ensured, effectively preventing safety accidents caused by misoperation and improving the overall safety and reliability of the system operation. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a flowchart of a fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to an embodiment of this application. Detailed Implementation

[0024] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0025] The following specific examples illustrate the implementation of this application. Those skilled in the art can easily understand other advantages and effects of this application from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. This application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this application. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0026] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this application, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.

[0027] It should also be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of this application. The illustrations only show the components related to this application and are not drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0028] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details.

[0029] This application provides a fixed-station copper slag temperature-controlled crystallization waste heat recovery method, based on a fixed-station copper slag temperature-controlled crystallization waste heat recovery system. The system includes a hoisting slag pot for receiving copper smelting slag, a fixed slag pot outer casing for housing the hoisting slag pot, a waste heat recovery component disposed within the fixed slag pot outer casing and exchanging heat with the hoisting slag pot, a heat exchange component inserted into the copper slag for heat exchange, a steam drum for steam-water separation, and a control system. (Refer to...) Figure 1 The method includes the following steps: Step 1: Hoist the transportable slag pot containing copper smelting slag into the outer casing of the fixed slag pot. The loading temperature of the copper smelting slag is 600℃ to 1500℃. Preferably, the charging temperature of copper smelting slag is 800℃ to 1300℃. This temperature range covers the common slag discharge temperatures of copper smelting furnaces and copper blowing furnaces, and can be adapted to the slag discharge conditions of most copper smelting enterprises. The connection can be completed without making significant adjustments to the original slag discharge process. Step 2: Cover the top of the slag pot with the slag pot lid, slide the heat exchange component to the slag pot lid, and insert it into the copper slag through the slag pot lid; Step 3: Pass deoxygenated water into the waste heat recovery component to absorb the heat transferred from the outer wall of the hoistable slag tank and generate a steam-water mixture. The steam-water mixture is separated by a steam drum, and the separated steam is sent to the steam output system. Step 4: Introduce heat exchange medium into the heat exchange assembly to exchange heat and regulate the temperature field inside the copper slag; Step 5: The control system adjusts the medium flow rate, pressure and operating stage of the waste heat recovery component and / or heat exchange component in stages according to the temperature of the copper slag, so that the copper slag is cooled by temperature control, crystallization regulation and waste heat recovery according to the set cooling curve. Step 6: When the copper slag reaches the target discharge temperature or completes the set temperature control process, remove the heat exchange component, lift the slag pot cover, and lift the hoistable slag pot out of the fixed slag pot outer casing.

[0030] In this embodiment, the conventional hoistable slag pot does not function as a boiler piping or pressure vessel. Instead, the waste heat recovery components, steam drum, steam piping, heat exchange components, and slag pot cover are centrally located in a fixed position. This allows the hoistable slag pot body to participate in waste heat recovery without integrating any pressurized heat exchange piping, fundamentally eliminating the risks of interface leakage and operational interference caused by the heat exchange piping being hoisted and transported with the slag pot. This improves system safety, maintenance convenience, and compatibility with existing copper plant slag pot operation methods. The waste heat recovery components perform primary heat exchange on the outer wall of the slag pot, reducing the risk of liquid water directly entering the high-temperature copper slag interior. The heat exchange components perform secondary heat exchange and temperature field regulation inside the copper slag, improving the problem of the slag pot being cold on the outside and hot on the inside. This enables controlled cooling of the copper slag, crystallization control, waste heat recovery, and target outlet temperature regulation. Under the constraints of subsequent resource recovery processing requirements, the system performs controllable heat exchange, synergistically optimizing the copper slag cooling curve, steam production, and target outlet temperature.

[0031] In one embodiment, in step 3, the steam-water mixture generated by the waste heat recovery component is separated by a steam drum, and the separated steam is output into the steam output system; alternatively, the separated steam enters the heat exchange component and further absorbs heat inside the copper slag to increase the steam dryness or temperature. This flexible switching of the steam utilization path allows the steam generated on the outer side to be directly exported for utilization, or to participate in internal heat exchange as a heat exchange medium in the heat exchange component, realizing the connection and synergistic utilization of the medium between the internal and external heat exchange systems.

[0032] In one embodiment, in step 4, the method of introducing the heat exchange medium is switched based on a first set temperature, including: when the copper slag temperature is higher than the first set temperature, steam or inert gas is introduced into the heat exchange component, and liquid water is prohibited from entering the heat exchange component; when the copper slag temperature is lower than the first set temperature and the safety interlock conditions of the heat exchange component pressure, temperature, position, steam drum water level, and slag pot cover status are met, deoxygenated water, steam-water mixture, or low-temperature steam is allowed to be introduced into the heat exchange component, wherein the first set temperature is 500°C to 800°C. Preferably, the first set temperature is 650°C to 750°C. This temperature range is much lower than the initial slag discharge temperature of copper smelting slag and higher than the saturation temperature of water under standard pressure. This can ensure that the liquid water does not boil violently when it encounters the high-temperature slag during the high-temperature stage, while starting the water phase enhanced heat exchange as early as possible and improving the waste heat recovery efficiency.

[0033] This phased media switching strategy effectively avoids the safety risk of boiling over caused by contact between liquid water and high-temperature molten slag during the high-temperature stage of copper slag, while allowing the introduction of deoxygenated water or steam-water mixtures to enhance heat exchange on the tube side during the low-temperature stage, thus achieving safe and efficient internal heat exchange control throughout the entire process.

[0034] According to a specific implementation of an embodiment of this application, the security interlocking conditions include: When the slag container is not seated in the fixed slag container outer casing, the slag container lid must not be lowered; The heat exchange components must not be lowered if the slag tank cover is not in place. When the heat exchange components are not in place, it is forbidden to introduce heat exchange medium into the heat exchange components; When the temperature of the copper slag is higher than the first set temperature, liquid water is prohibited from entering the heat exchange components; If the steam drum water level, pressure, or safety valve is abnormal, the system must not be operated under increased load. Lifting the slag tank lid is prohibited until the heat exchange components are fully removed.

[0035] In this embodiment, the interlocking logic constitutes a complete sequential action control chain from the slag pot being seated to the crane lifting it out, ensuring the safe and reliable action sequence between the high-temperature molten slag, the steam system, the heat exchange components and the slag pot cover, and preventing safety accidents caused by misoperation.

[0036] In one embodiment, the pull-out heat exchange assembly includes: Stop the flow of liquid water into the heat exchange component and switch to steam or inert gas to purge the inside of the heat exchange component to reduce the residual moisture and pressure inside the heat exchange component. Keep the slag pot lid covering the top of the hoistable slag pot, and slowly raise the heat exchange components relative to the slag pot lid; The control system monitors the position and upward resistance of the heat exchange components. Once it is confirmed that the heat exchange components have completely detached from the copper slag and entered a safe position, the slag pot cover is allowed to be lifted and hoisted.

[0037] The tube removal procedure eliminates residual moisture and pressure hazards inside the tube by purging and depressurizing, and ensures the safety and reliability of the tube removal process through dual monitoring of position and resistance.

[0038] In one embodiment, the slag pot lid is lifted and hoisted via a foldable gantry mechanism and a lifting mechanism, wherein allowing the slag pot lid to be lifted and hoisted includes: After the slag pot lid is lifted to a high position by the lifting mechanism, the foldable gantry mechanism folds it to the clearance position; After the control system confirms that the foldable gantry mechanism has made proper clearance, the overhead crane is allowed to lift out the slag hopper.

[0039] Specifically, the foldable gantry mechanism supports the slag pot lid and heat exchange components during slag pot heat exchange operations. When the slag pot needs to be lifted out, it folds to a clearance position, providing passage space and enabling safe and smooth turnover of the slag pot under a fixed-position equipment layout. In this embodiment, the safety interlock conditions also include prohibiting the foldable gantry mechanism from folding when the slag pot lid is not raised to a safe position; and prohibiting the crane from lifting the slag pot when the foldable gantry mechanism is not folded to a clearance position.

[0040] In one embodiment, the step of adjusting the medium flow rate, pressure, and operating stage of the waste heat recovery component and / or heat exchange component in stages according to the copper slag temperature via a control system includes: The control system has multiple preset cooling curves, each corresponding to a different target outlet temperature of copper slag or different downstream process requirements. The control system calls up the corresponding set cooling curve according to the needs of subsequent processes such as copper slag return to furnace, crushing, flotation, magnetic separation, storage or transfer; Based on the temperature-time relationship contained in the set cooling curve, the flow rate and pressure of the medium in the waste heat recovery component and / or heat exchange component are adjusted in stages. Each set cooling curve includes an effective crystallization window for the copper matte phase, which is 900℃~970℃. The cooling rate within the window is 5℃ / h~50℃ / h, and the dwell time within the window is 1 hour~6 hours.

[0041] In this embodiment, precise temperature control can be achieved by matching the requirements of different processes. This balances waste heat recovery efficiency and cooling pace while ensuring the crystallization effect of copper slag. It satisfies the temperature requirements of downstream processes for copper slag while avoiding energy waste from excessive cooling or insufficient cooling that could affect subsequent processing. This achieves synergistic optimization of waste heat recovery and subsequent copper slag treatment. In this embodiment, the flow rate of the heat exchange medium is controlled when the copper slag enters the effective crystallization window, allowing for slow cooling and promoting the precipitation, growth, aggregation, and sedimentation of the copper matte phase. 900℃~970℃ is the key control window for the formation, growth, aggregation, and sedimentation of the copper matte phase. By controlling the flow rate of the heat exchange medium, the cooling rate within this window is slowed, ensuring sufficient time for the copper matte particles to complete precipitation and growth. This avoids excessively rapid cooling leading to finer copper matte particles that cannot be effectively recovered through subsequent sorting processes. This fundamentally improves the recovery rate of valuable components and enhances the economic benefits of copper slag resource utilization.

[0042] In one embodiment, the method further includes: The control system dynamically adjusts the flow rate of the medium in the waste heat recovery component and the heat exchange component based on the difference between the real-time temperature of the copper slag and the target temperature of the set cooling curve at the same time point, using a PID control algorithm. Specifically, this includes: When the real-time temperature of the copper slag is higher than the target temperature of the set cooling curve, the medium flow rate is increased to enhance heat exchange; when the real-time temperature of the copper slag is lower than the target temperature of the set cooling curve, the medium flow rate is reduced to weaken heat exchange; the control system collects temperature data inside and outside the copper slag in real time through temperature sensors to form a closed-loop feedback control.

[0043] In this embodiment, dynamic closed-loop regulation is achieved through a PID algorithm, which can offset the influence of interference factors such as initial temperature fluctuations of copper slag and changes in ambient temperature on the cooling effect, ensuring that the temperature of copper slag always changes along the preset curve, further improving the temperature control accuracy, ensuring the uniformity and stability of copper slag crystallization, and at the same time ensuring that the waste heat recovery component is always maintained under an appropriate heat exchange load, avoiding sudden changes in heat exchange load from affecting the service life of the equipment, thus balancing temperature control accuracy and equipment operation stability.

[0044] In one embodiment, the phased operation of the control system includes at least the following: During the high-temperature rapid cooling stage, when the temperature of the copper slag is higher than the second set temperature, the waste heat recovery component operates at the first medium flow rate, and the heat exchange component is introduced with steam or inert gas and operates at the second medium flow rate. During the medium-temperature slow cooling stage, when the temperature of the copper slag is between the third set temperature and the second set temperature, the waste heat recovery component operates with the third medium flow rate, and the heat exchange component is circulated with deoxygenated water or a steam-water mixture and operates with the fourth medium flow rate. During the low-temperature slow cooling stage, when the temperature of the copper slag is lower than the third set temperature, the waste heat recovery component operates at the fifth medium flow rate and the heat exchange component operates at the sixth medium flow rate. The second set temperature is higher than the third set temperature, and the medium flow rate at each stage is set and adjusted by the control system according to the temperature gradient of the set cooling curve.

[0045] In this embodiment, staged temperature-controlled cooling can match the crystallization characteristics of copper slag in different temperature ranges. In the high-temperature range, rapid cooling quickly overcomes the unstable crystallization zone of copper slag, avoiding the formation of harmful crystalline phases. In the medium-temperature range, slow cooling provides sufficient time and a suitable temperature environment for the growth of the target crystalline phase. In the low-temperature range, the cooling rate is further slowed down to ensure complete crystallization and ultimately obtain a crystallized product with uniform crystalline phase and stable performance. At the same time, different heat exchange media and flow rates are adapted to different temperature ranges, which can maximize the efficiency of waste heat recovery. The high-quality steam recovered can be directly utilized, improving the recovery and utilization rate of copper slag waste heat.

[0046] In one embodiment, the target outlet temperature is set according to the needs of subsequent processes such as copper slag remelting, crushing, flotation, magnetic separation, storage, or transfer. The target outlet temperature ranges from 100°C to 900°C. By setting the corresponding outlet temperature to match the needs of different downstream processes, it is possible to avoid the copper slag temperature being too high and affecting the safety of downstream processes, and also to avoid unnecessary waste heat due to excessive cooling, thus balancing the convenience of subsequent processing and the benefits of waste heat recovery. For example, when the subsequent process is flotation or magnetic separation, the target outlet temperature is set to a lower temperature suitable for crushing operations; when the subsequent process is remelting, the target outlet temperature can be set to a higher temperature to save energy consumption for reheating. To address the differentiated requirements of different downstream processes for the copper slag outlet temperature, the temperature-controlled crystallization method achieves flexible adaptation to the same system by adjusting the set cooling curve and the target outlet temperature, accommodating multiple process routes.

[0047] In one embodiment, the complete operation process of the fixed-station copper slag temperature-controlled crystallization waste heat recovery method is described in detail, specifically including the following steps: First, a hoistable slag pot containing copper smelting slag is lifted by a crane to a position directly above the outer casing of a fixed slag pot. It is then slowly lowered so that the hoistable slag pot sits within the receiving cavity of the fixed slag pot. Once the control system confirms that the hoistable slag pot is in place, the slag pot lid is lowered, and a lifting mechanism covers the top opening of the hoistable slag pot. After the slag pot lid descends into place, the control system allows the heat exchange assembly to slowly descend through the insertion hole on the slag pot lid and insert into the copper slag to the set depth. Once the heat exchange assembly is in place, the control system allows the heat exchange medium to be introduced into it. Meanwhile, the deoxygenated water supply system continuously supplies deoxygenated water to the waste heat recovery assembly fixed inside the outer casing of the stationary slag pot. The heat carried by the copper slag is conducted to the waste heat recovery assembly through radiation and convection via the outer wall of the hoistable slag pot. Inside the waste heat recovery assembly, the deoxygenated water absorbs heat and produces a steam-water mixture, which is then fed into the steam drum for steam-water separation. The separated saturated steam is fed into the heat exchange assembly for secondary heat absorption, or transported to the plant's steam network or power generation system for utilization, thus realizing the recovery and resource utilization of the sensible heat of the copper slag. The control system monitors the temperature of the copper slag in real time and adjusts the flow rate and pressure of the medium in the waste heat recovery component and the heat exchange component in stages according to the set cooling curve, so that the copper slag can complete temperature control cooling, crystallization regulation and waste heat recovery under the set cooling curve. Once the copper slag reaches the target outlet temperature, the control system executes the tube removal procedure. First, it stops the flow of liquid water into the heat exchange components and switches to steam or inert gas to purge the inside of the heat exchange components, reducing residual moisture and pressure inside the components. Subsequently, the slag pot lid remains covering the top of the hoistable slag pot, and the heat exchange components slowly rise relative to the slag pot lid; The control system monitors the position and upward resistance of the heat exchange components. Once it confirms that the heat exchange components are completely detached from the copper slag and in a safe position, the slag pot lid is allowed to be raised to the highest position. After the slag pot lid is raised to the highest position, the foldable gantry mechanism folds to the clearance position. After the control system confirms that the foldable gantry mechanism has cleared the clearance position, the overhead crane is allowed to lift out the slag pot, completing a full waste heat recovery operation cycle.

[0048] In one embodiment, the safety interlock control logic executed by the control system is described to construct a complete sequential action control chain from the slag pot being seated to its hoisting out.

[0049] During the tank loading stage, if the hoistable slag container is not seated in the fixed slag container outer casing, the control system prohibits the slag container lid from descending; if the slag container lid is not in place, the control system prohibits the heat exchange components from descending; if the heat exchange components are not in place, the control system prohibits the introduction of media into the heat exchange components. This interlocking logic ensures that each component operates in the correct sequence, preventing equipment damage or safety accidents due to misoperation.

[0050] During operation, when the temperature of the copper slag exceeds the first set temperature, the control system prohibits liquid water from entering the heat exchange components to prevent the high-temperature molten slag from boiling over upon contact with water. When the steam drum water level, pressure, or safety valve is abnormal, the control system prohibits the system from operating at increased load to ensure the safe and stable operation of the water-steam system.

[0051] During the unloading stage, if the heat exchange components are not fully removed, the control system prohibits the slag pot lid from being lifted; if the slag pot lid is not lifted to a safe position, the control system prohibits the foldable gantry mechanism from being folded; if the foldable gantry mechanism is not folded to a clearance position, the control system prohibits the crane from lifting out the slag pot that can be lifted.

[0052] The above interlocking logic constitutes a complete sequential action control chain from the slag pot being seated to its hoisting out, ensuring the safe and reliable sequence of actions between the high-temperature molten slag, water and steam system, heat exchange components, slag pot cover, foldable gantry mechanism and lifting mechanism, effectively preventing safety accidents caused by misoperation and improving the overall safety and reliability of the system.

[0053] It is understood that the heat exchange medium in the above embodiments is not limited to deoxygenated water, steam, or inert gas, and other suitable heat exchange media can be selected according to the actual working conditions. It is understood that the specific value of the target outlet temperature can be determined comprehensively based on the copper slag composition, subsequent process requirements, and on-site working conditions, and this application does not impose any restrictions on this.

[0054] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for recovering waste heat from copper slag temperature-controlled crystallization at a fixed workstation, based on a waste heat recovery system for copper slag temperature-controlled crystallization at a fixed workstation, characterized in that... The system includes a hoisting slag pot for receiving copper smelting slag, a fixed slag pot outer casing for housing the hoisting slag pot, a waste heat recovery component disposed inside the fixed slag pot outer casing and exchanging heat with the hoisting slag pot, a heat exchange component inserted into the copper slag for heat exchange, a steam drum for steam-water separation, and a control system. The method includes the following steps: Step 1: Hoist the transportable slag pot containing copper smelting slag into the outer casing of the fixed slag pot. The loading temperature of the copper smelting slag is 600℃ to 1500℃. Step 2: Cover the top of the slag pot with the slag pot lid, slide the heat exchange component to the slag pot lid, and insert it into the copper slag through the slag pot lid; Step 3: Pass deoxygenated water into the waste heat recovery component to absorb the heat transferred from the outer wall of the hoistable slag tank and generate a steam-water mixture. The steam-water mixture is separated by a steam drum, and the separated steam is sent to the steam output system. Step 4: Introduce heat exchange medium into the heat exchange assembly to exchange heat and regulate the temperature field inside the copper slag; Step 5: The control system adjusts the medium flow rate, pressure and operating stage of the waste heat recovery component and / or heat exchange component in stages according to the temperature of the copper slag, so that the copper slag is cooled by temperature control, crystallization regulation and waste heat recovery according to the set cooling curve. Step 6: When the copper slag reaches the target discharge temperature or completes the set temperature control process, remove the heat exchange component, lift the slag pot cover, and lift the hoistable slag pot out of the fixed slag pot outer casing.

2. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 1, characterized in that, In step 3, the steam-water mixture generated by the waste heat recovery component is separated by steam-water separation in the steam drum, and the separated steam enters the steam output system for output; or, the separated steam enters the heat exchange component and further absorbs heat inside the copper slag to increase the steam dryness or temperature.

3. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 1, characterized in that, In step 4, the method of introducing the heat exchange medium is switched based on the first set temperature, including: when the temperature of the copper slag is higher than the first set temperature, steam or inert gas is introduced into the heat exchange component, and liquid water is prohibited from entering the heat exchange component; when the temperature of the copper slag is lower than the first set temperature and the safety interlock conditions of the pressure, temperature, position, steam drum water level and slag pot cover status of the heat exchange component are met, deoxygenated water, steam-water mixture or low-temperature steam is allowed to be introduced into the heat exchange component, wherein the first set temperature is 500℃ to 800℃.

4. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 3, characterized in that, The safety interlock conditions include: When the slag container is not seated in the fixed slag container outer casing, the slag container lid must not be lowered; The heat exchange components must not be lowered if the slag tank cover is not in place. When the heat exchange components are not in place, it is forbidden to introduce heat exchange medium into the heat exchange components; When the temperature of the copper slag is higher than the first set temperature, liquid water is prohibited from entering the heat exchange components; If the steam drum water level, pressure, or safety valve is abnormal, the system must not be operated under increased load. Lifting the slag tank lid is prohibited until the heat exchange components are fully removed.

5. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 1, characterized in that, The pull-out heat exchange assembly includes: Stop the flow of liquid water into the heat exchange component and switch to steam or inert gas to purge the inside of the heat exchange component to reduce the residual moisture and pressure inside the heat exchange component. Keep the slag pot lid covering the top of the hoistable slag pot, and slowly raise the heat exchange components relative to the slag pot lid; The control system monitors the position and upward resistance of the heat exchange components. Once it is confirmed that the heat exchange components have completely detached from the copper slag and entered a safe position, the slag pot cover is allowed to be lifted and hoisted.

6. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 5, characterized in that, The slag pot lid is lifted and transported via a foldable gantry mechanism and a lifting mechanism. The lifting and transport of the slag pot lid includes: After the slag pot lid is lifted to a high position by the lifting mechanism, the foldable gantry mechanism folds it to the clearance position; After the control system confirms that the foldable gantry mechanism has made proper clearance, the overhead crane is allowed to lift out the slag hopper.

7. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 1, characterized in that, The control system adjusts the medium flow rate, pressure, and operating stage of the waste heat recovery component and / or heat exchange component in stages according to the copper slag temperature, including: The control system has multiple preset cooling curves, each corresponding to a different target outlet temperature of copper slag or different downstream process requirements. The control system calls up the corresponding set cooling curve according to the needs of subsequent processes such as copper slag return to furnace, crushing, flotation, magnetic separation, storage or transfer; Based on the temperature-time relationship contained in the set cooling curve, the flow rate and pressure of the medium in the waste heat recovery component and / or heat exchange component are adjusted in stages. Each set cooling curve includes an effective crystallization window for the copper matte phase, which is 900℃~970℃. The cooling rate within the window is 5℃ / h~50℃ / h, and the dwell time within the window is 1 hour~6 hours.

8. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 7, characterized in that, The method further includes: The control system dynamically adjusts the flow rate of the medium in the waste heat recovery component and the heat exchange component based on the difference between the real-time temperature of the copper slag and the target temperature of the set cooling curve at the same time point, using a PID control algorithm. Specifically, this includes: When the real-time temperature of the copper slag is higher than the target temperature of the set cooling curve, the medium flow rate is increased to enhance heat exchange; when the real-time temperature of the copper slag is lower than the target temperature of the set cooling curve, the medium flow rate is reduced to weaken heat exchange; the control system collects temperature data inside and outside the copper slag in real time through temperature sensors to form a closed-loop feedback control.

9. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to claim 1, characterized in that, The phased operation of the control system includes at least the following stages: During the high-temperature rapid cooling stage, when the temperature of the copper slag is higher than the second set temperature, the waste heat recovery component operates at the first medium flow rate, and the heat exchange component is introduced with steam or inert gas and operates at the second medium flow rate. During the medium-temperature slow cooling stage, when the temperature of the copper slag is between the third set temperature and the second set temperature, the waste heat recovery component operates with the third medium flow rate, and the heat exchange component is circulated with deoxygenated water or a steam-water mixture and operates with the fourth medium flow rate. During the low-temperature slow cooling stage, when the temperature of the copper slag is lower than the third set temperature, the waste heat recovery component operates at the fifth medium flow rate and the heat exchange component operates at the sixth medium flow rate. The second set temperature is higher than the third set temperature, and the medium flow rate at each stage is set and adjusted by the control system according to the temperature gradient of the set cooling curve.

10. The fixed-station copper slag temperature-controlled crystallization waste heat recovery method according to any one of claims 1-9, characterized in that, The target outlet temperature is set according to the needs of subsequent processes such as copper slag return to furnace, crushing, flotation, magnetic separation, storage or transfer, and the target outlet temperature is 100℃ to 900℃.

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