Zinc-containing waste steel resource utilization complete equipment and application method thereof

Abstract

The invention discloses zinc-containing waste steel resource utilization complete equipment and an application method thereof, and belongs to the technical field of secondary resource recovery and hydrometallurgy. The zinc-containing waste steel resource utilization complete equipment is characterized in that a dezincification system conducts dezincification treatment on zinc-containing waste steel according to an alkaline leaching system to achieve recovery of the zinc-containing waste steel, and a purification system purifies dezincification alkali liquor; the electrolysis system is used for electrolytic zinc extraction, the zinc particle washing system is used for washing zinc particles, the rinsing system is used for rinsing waste steel, the drying system is used for drying the waste steel, the tail gas treatment system is used for washing and recycling tail gas, and the dezincification process is enhanced by controlling the sodium hydroxide concentration, the leaching temperature and the micro-nano bubble flow speed. According to the method, the aim of efficiently extracting high-purity regenerated zinc from the zinc-containing waste steel can be achieved through multiple times of dezincification and multiple times of rinsing optimization, meanwhile, the problems of high energy consumption and secondary pollution of traditional pyrogenic process treatment are avoided, the dezincification efficiency is improved, the cost is reduced, and a sustainable path is provided for cyclic utilization of zinc resources.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of secondary resource recycling and hydrometallurgy, and particularly relates to a complete equipment for recycling and utilizing zinc-containing scrap steel and an application method thereof. BACKGROUND

[0002] In recent years, the global zinc concentrate output decreases year by year, and the resource exhaustion pressure is increasing, which seriously restricts the sustainable development of the zinc industry. Therefore, it is urgent to explore new supply channels. However, the annual output of galvanized steel sheet is huge, and its continuous high output has formed a huge demand pressure on zinc resources. In the process of scrap steel recycling and utilization, zinc in scrap steel is easy to evaporate into steam due to its low boiling point, which is difficult to separate, and zinc oxide particles generated by reaction with oxygen are easy to cause equipment blockage and secondary pollution. In addition, zinc oxide dust has strong adsorption, which is easy to carry heavy metals and other harmful substances, which not only harms the environment and human health, but also affects the quality stability of recycled steel.

[0003] The current zinc removal technology mainly includes mechanical removal and reprocessing method, vacuum heating method and chemical dissolution method. The mechanical removal and reprocessing method has fast treatment speed and high efficiency, but has problems such as complex process flow of zinc recovery and bad environment. The vacuum heating method utilizes the low boiling point of zinc, and makes zinc evaporate to the recovery device through the electric heating ring in the vacuum furnace. However, this method has great control difficulty, cannot realize continuous production and has high cost. SUMMARY

[0004] To solve the above problems and technical defects, the application adopts the following technical scheme, a complete equipment for recycling and utilizing zinc-containing scrap steel, comprising: a zinc removal system module, a purification system, an electrolysis system, a zinc particle washing system, a rinsing system, a drying system and a tail gas treatment system; a zinc removal system, used for zinc removal treatment of zinc-containing scrap steel according to an alkaline leaching system to realize recycling of zinc-containing scrap steel; a purification system, used for purification of zinc removal alkali liquor; an electrolysis system, used for zinc extraction by electrolysis; a zinc particle washing system, used for washing of zinc particles; a rinsing system, used for rinsing of scrap steel; a drying system, used for drying of scrap steel; a tail gas treatment system, used for washing and recycling of tail gas, and the zinc removal process is strengthened by controlling the concentration of sodium hydroxide, leaching temperature and micro-nano bubble flow rate.

[0005] Preferably, the zinc removal system comprises: a feeding unit, used for feeding zinc-containing scrap steel into the zinc removal system; A plurality of continuous zinc removal devices for sequentially removing zinc from scrap steel in an alkaline system; A leaching solution circulation unit comprising a pump set and pipelines for supplying and circulating sodium hydroxide solution to the zinc removal baskets; A micro-nano bubble generator for improving the dispersibility of air, oxygen-enriched air and industrial oxygen using micro-nano bubbles, and for synergistically strengthening the zinc removal process through efficient oxygen supply, interface activation and hydroxyl radicals generated during collapse; A solution storage tank for storing the solution reaching the target zinc concentration for the next step of electrolysis; An electrolysis post-solution tank for recovering and storing the electrolysis solution, which can make up for the liquid level deficiency of the last zinc removal device; A heating and temperature control unit for maintaining the zinc removal solution temperature in the range of 20-95℃.

[0006] Further, the zinc removal devices are a plurality of continuous zinc removal baskets connected with zinc removal tanks or a plurality of continuous zinc removal drums connected in series, for continuously removing zinc from scrap steel in an alkaline system; The zinc removal baskets use a crane and mechanical gripper conveying mechanism to convey scrap steel between zinc removal tanks; The zinc removal drums use a plate chain conveying mechanism to convey scrap steel between drums; An alkali solution continuous replenishment system is provided between the plurality of continuous zinc removal devices, and the working mode includes: When the leaching solution in the first zinc removal device is pumped to the solution storage tank due to reaching the target zinc concentration, the liquid level detector sends a signal to start the pump set to replenish the leaching solution in the second zinc removal device to the first zinc removal device; The liquid level deficiency of the subsequent i-th zinc removal device is continuously replenished by the solution in the i+1-th zinc removal device; The liquid level deficiency of the last zinc removal device is replenished by the electrolysis post-solution tank or scrap steel rinsing water.

[0007] Preferably, the purification system comprises: A stirred tank for generating reactions in the leaching solution using lime to generate CaCO3 and NaOH, achieving regeneration and recycling of sodium hydroxide solution; A filter press for solid-liquid separation of the decarbonized leaching solution, trapping calcium carbonate precipitate and suspended solids, so that the solution entering the electrolysis process meets the process requirements.

[0008] Preferably, the electrolysis system uses stainless steel as the anode and lead-calcium-tin composite electrode as the cathode, and the electrolysis system comprises: An electrolysis pre-solution tank for storing the purified zinc-containing leaching solution, and realizing quantitative delivery to the electrolysis tank through a liquid level controller; An electrolysis tank for realizing electrochemical deposition of zinc ions; A centrifuge is used for solid-liquid separation of electrolytic products to obtain zinc particle products, and the separated electrolyte is returned to the electrolyte tank for recycling; Rinse water is used to wash the zinc particles obtained by electrolysis to achieve efficient separation of zinc particles and residual electrolyte.

[0009] Preferably, the rinsing system comprises: A plurality of consecutive rinsing devices for rinsing the zinc-depleted scrap steel multiple times; A rinse solution circulating unit comprising a pump set and pipelines for supplying and circulating sodium hydroxide solution to the electrolyte tank.

[0010] Further, the rinsing device in the rinsing system is n consecutive rinsing baskets connected with rinsing tanks or n consecutive rinsing drums connected in series, for continuous rinsing of zinc-containing scrap steel in an alkaline system; The rinsing basket uses a crane and a mechanical gripper conveying mechanism to convey scrap steel between the rinsing tanks; The rinsing drum uses a plate chain conveying mechanism to convey scrap steel between the drums; An alkali solution continuous replenishment system is provided between the plurality of consecutive rinsing devices, and the working mode includes: When the leaching solution in the first rinsing device is pumped to the storage tank due to reaching the target zinc concentration, the liquid level detector sends a signal to start the pump set to replenish the leaching solution in the second rinsing device to the first rinsing device; The liquid level of the subsequent i-th rinsing device is continuously replenished by the solution in the i+1-th rinsing device; The liquid level of the last rinsing device is replenished by fresh tap water.

[0011] Preferably, the drying system comprises: A drying tank for drying the rinsed scrap steel using hot air convection, with the temperature in the tank maintained at 50-400°C; A blower for continuously conveying dry air heated by a heater to the drying tank, with the air speed controlled at 2-5 m / s to ensure that the water on the surface of the scrap steel evaporates to residual moisture ≤0.5%, while water vapor is discharged.

[0012] Preferably, the tail gas treatment system comprises: A tail gas washing tower for purifying sodium hydroxide in the waste gas by countercurrent contact with the spray absorption liquid.

[0013] An application method of a zinc-containing scrap steel resource utilization complete equipment, which realizes the contents of the zinc-containing scrap steel resource utilization complete equipment as described above, and the specific steps include: Step 1, the zinc-containing scrap steel enters the n-time zinc removal device in sequence through the conveying mechanism, and is subjected to zinc removal in a sodium hydroxide solution by passing in micro-nano bubbles; Step 2, the leaching solution is subjected to lime stirring treatment and then enters an electrolysis system to recover zinc; Step 3, the electrolyte is subjected to electrolysis and centrifugation and then is used in a reflux cycle; Step 4, the zinc-removed scrap steel enters the n-time rinsing device and is subjected to rinsing in sequence; Step 5, the rinsed scrap steel is dried and briquetted and then is output as clean scrap steel; Step 6, the tail gas is purified by countercurrent contact with the spray absorption liquid in the tail gas washing tower.

[0014] Compared with the prior art, the application has the following beneficial effects: (1) The application constructs a complete circular treatment system integrating multiple continuous zinc removal and rinsing and micro-nano bubble enhanced mass transfer technology through multiple continuous zinc removal devices, multiple continuous rinsing devices, a conveying system, an alkali solution circulation system and a rinsing water circulation system, realizes resource utilization of zinc-containing scrap steel and simultaneous washing and recovery of tail gas, and solves the problems of limited zinc removal efficiency, low resource comprehensive utilization rate, insufficient systematicness of the process flow and potential environmental risk in the prior art; (2) The application adopts an alkali method to treat zinc-containing scrap steel, realizes efficient extraction of high-purity regenerated zinc from the zinc-containing scrap steel through multiple zinc removal and multiple rinsing optimization, avoids the problems of high energy consumption and secondary pollution in traditional pyrometallurgical treatment through closed cycle design, improves the zinc removal efficiency, reduces the cost, and realizes circular utilization of various solid residues generated in the production process through treatment in the system, completely harmless treatment of hazardous waste, and zero wastewater discharge of the entire process flow, thereby providing a sustainable path for the cyclic utilization of zinc resources; (3) The application improves the mass transfer process by introducing micro-nano bubble technology, the micro-nano bubbles greatly improve the gas-liquid contact efficiency by virtue of their special physical properties, the high-activity free radicals generated when the bubbles collapse can effectively break the zinc-iron alloy structure, and the surface properties of the bubbles optimize the reaction interface environment, so that the zinc removal reaction efficiency is comprehensively improved through the synergistic action of multiple mechanisms; (4) The multiple continuous circular architecture adopted in the application realizes efficient utilization of materials, and through establishment of a reasonable concentration gradient distribution, different concentrations of process liquids are matched with materials containing corresponding amounts of zinc for treatment, which not only ensures the best reaction driving force but also reduces the chemical raw material consumption by more than 30% and the process water reuse rate by more than 80%; (5) This application ensures the excellent characteristics of the final product through precise process control. The zinc removal rate on the surface of the treated steel is higher than 99.9%, which meets the standard requirements for high-quality recycled steel. The zinc product obtained by electrolysis has a complete crystal structure and a high purity level, and can be sold directly as commercial zinc, realizing the dual value-added recycling of waste resources. Attached Figure Description

[0015] In the attached diagram: Figure 1 This is a schematic diagram of the application method steps in an embodiment of this application; Figure 2 This is a schematic diagram of the dezincification basket device according to an embodiment of this application; Figure 3 This is a schematic diagram of the zinc stripping drum device according to an embodiment of this application. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments. Generally, the components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations.

[0017] Example 1 like Figure 2 and Figure 3 As shown, a complete set of equipment for the resource utilization of zinc-containing scrap steel includes: a dezincification system, a purification system, an electrolysis system, a zinc particle washing system, a rinsing system, a drying system, and a tail gas treatment system; The zinc removal system utilizes an alkaline leaching system to remove zinc from zinc-containing scrap steel, enabling its recycling. The purification system purifies the zinc removal alkaline solution, the electrolysis system extracts zinc, the rinsing system washes the scrap steel, the drying system dries the scrap steel, and the tail gas treatment system washes and recovers the tail gas. The zinc removal process is enhanced by controlling the sodium hydroxide concentration, leaching temperature, and micro-nano bubble flow rate.

[0018] The zinc removal system includes: The feeding unit is used to feed zinc-containing scrap steel into the dezincification system; n consecutive dezincification units (n≥1) are used to dezincify zinc-containing scrap steel in an alkaline system. The leachate circulation unit, including pump sets and pipelines, is used to supply and circulate sodium hydroxide solution to the zinc stripping basket; The micro-nano bubble generator cooperates with the hydroxyl radical generated during the interface activation and collapse of the micro-nano bubble to strengthen the dezincification process through efficient oxygen supply, and the micro-nano bubble is used to improve the dispersibility of air, oxygen-enriched air and industrial oxygen. Of course, those skilled in the art can also use the gas pipeline to blow air, oxygen-enriched air and industrial oxygen, although the effect is not as good as that of the micro-nano bubble, but increasing the gas flow can also achieve the effect of the present application. The airflow flow rate provided by the micro-nano bubble generating device matches the scrap steel treatment capacity, and the range is 10-1000 Nm3 / (h·t), preferably 40-700 Nm3 / (h·t); The liquid storage tank is used to store the solution reaching the target zinc concentration for the next electrolysis step; The post-electrolysis liquid tank is used to recover and store the solution after electrolysis, and can make up the liquid level vacancy of the last dezincification device; The heating and temperature control unit is used to maintain the dezincification liquid temperature in the range of 20-95℃.

[0019] The dezincification device in the dezincification system can be n continuous dezincification baskets connected with dezincification tanks (n≥1) or n continuous dezincification rollers connected in series (n≥1), which are used for continuous dezincification of scrap steel containing zinc in an alkaline system; The dezincification basket adopts a crane and a mechanical gripper conveying mechanism for conveying scrap steel between the dezincification tanks; The dezincification roller adopts a plate chain conveying mechanism for conveying scrap steel between the rollers.

[0020] An alkali solution continuous replenishment system is provided between the n continuous dezincification devices, and the working mode is as follows: When the leaching solution in the first dezincification device is pumped to the liquid storage tank because it reaches the target zinc concentration, the liquid level detector sends a signal to start the pump set to replenish the leaching solution in the second dezincification device to the first dezincification device; The liquid level vacancy of the subsequent i-th dezincification device (i is an integer from 1 to n-1) is continuously replenished by the solution in the i+1-th dezincification device; The liquid level vacancy of the last dezincification device is replenished by the post-electrolysis liquid tank or the scrap steel rinsing water.

[0021] The concentration of sodium hydroxide in the n dezincification devices is controlled in the range of 100-700 g / L, preferably 300-600 g / L.

[0022] The purification system comprises: The stirring tank: the leaching solution is stirred with lime to generate a reaction to generate CaCO3 and NaOH, thereby realizing the regeneration and recycling of the sodium hydroxide solution; The filter press: the decarburized leaching solution is subjected to solid-liquid separation to intercept calcium carbonate precipitate and suspended solids, so as to ensure that the solution entering the electrolysis process meets the process requirements.

[0023] The electrolysis system comprises: A pre-electrolysis liquid tank for storing the purified zinc-containing leaching solution and realizing quantitative delivery to the electrolytic cell through a liquid level controller; An electrolytic cell for realizing electrochemical deposition of zinc ions; A centrifuge for solid-liquid separation of electrolysis products to obtain zinc particle products, and the separated electrolyte is returned to the post-electrolysis liquid tank for recycling; Rinsing water for washing the zinc particles obtained by electrolysis to realize efficient separation of the zinc particles from residual electrolyte.

[0024] The electrolysis system uses stainless steel as the anode and a lead-calcium-tin composite electrode as the cathode, the electrolysis voltage is controlled at 2.1-3.0 V, preferably 2.5 V, and the zinc ion concentration in the electrolyte is not less than 30 g / L.

[0025] The zinc particle washing system comprises: Rinsing water for washing the zinc particles after centrifugation to realize efficient separation of the zinc particles from residual electrolyte.

[0026] The rinsing system comprises: n continuous rinsing devices (n≥1) for multiple rinsing of the zinc-depleted scrap steel; A rinsing liquid circulating unit comprising a pump set and pipelines for supplying and circulating sodium hydroxide solution to the post-electrolysis liquid tank.

[0027] The rinsing devices in the rinsing system can be n continuous rinsing baskets connected with n continuous rinsing tanks (n≥1) or n continuous rinsing drums (n≥1) connected in series, for continuous rinsing of zinc-containing scrap steel in an alkaline system; the rinsing baskets use a crane, a mechanical gripper conveying mechanism, for conveying scrap steel between the rinsing tanks; the rinsing drums use a plate chain conveying mechanism, for conveying scrap steel between the drums.

[0028] A rinsing water continuous replenishing system is provided between the n continuous rinsing devices, and the working mode comprises: When the leaching solution in the first rinsing device is pumped to the storage tank because it reaches the target zinc concentration, the liquid level detector sends a signal to start the pump set to replenish the leaching solution in the second rinsing device to the first rinsing device; The liquid level vacancy of the subsequent i-th rinsing device (i is an integer from 1 to n-1) is continuously replenished by the solution in the i+1-th rinsing device; The liquid level vacancy of the last rinsing device is replenished by fresh tap water.

[0029] The drying system comprises: The drying tank dries the rinsed scrap steel by hot air convection, and the temperature in the tank is maintained at 50-400℃; The air blower continuously sends the drying air heated by the heater to the drying tank, and the air speed is controlled at 2-5m / s to ensure that the water on the surface of the scrap steel evaporates to residual moisture ≤0.5%, while the water vapor is discharged.

[0030] The tail gas treatment system includes a tail gas washing tower which effectively purifies sodium hydroxide in the waste gas by countercurrent contact with the spray absorption liquid.

[0031] The travelling crane and the mechanical hand conveying mechanism are alkali-resistant equipment, and the speed is adjustable to control different dezincing times.

[0032] The plate chain conveying mechanism is an alkali-resistant plate chain, and the speed is adjustable to control different dezincing times.

[0033] Example 2 As shown in Figure 1 A zinc-containing scrap steel resource utilization complete equipment, the technical scheme comprises: The zinc-containing scrap steel is sent into the treatment system; The multiple dezincing rotary device implements dezincing on the scrap steel in an alkaline environment; The multiple rinsing rotary device implements multiple dezincing on the treated steel; The conveying mechanism realizes material transmission between devices; The alkali liquor circulation system is equipped with a storage tank, a pump set and a pipeline network to supply and recover sodium hydroxide solution to the dezincing device; The micro-nano bubble generating device introduces micro-nano bubbles during the circulation of the alkali liquor, and adjusts the air inlet rate according to the treatment load; The heating and temperature control system controls the process temperature in the range of 20-95℃; The rinsing water circulation system is equipped with a water storage tank, a cleaning tank and a water treatment and reuse device.

[0034] The leaching liquor is treated by lime stirring, reacts in the stirring tank to generate CaCO3 and NaOH, realizes regeneration and recycling of sodium hydroxide solution, and then is subjected to solid-liquid separation by a filter press after decarburization, to intercept calcium carbonate precipitate and suspended solids, so as to ensure that the solution entering the electrolysis process meets the process requirements; The operating concentration of sodium hydroxide in the multiple dezincing rotary device is in the range of 100-700g / L, and the preferred range is 300-600g / L; the air inlet rate of the micro-nano bubble generating device is matched with the treatment load, and is in the range of 10-1000 Nm3 / (h·t), preferably 40-800 Nm3 / (h·t).

[0035] The purified zinc-containing leaching solution is stored in an electrolysis front liquid tank, and is quantitatively delivered to the electrolytic cell through a liquid level control instrument, so that electrochemical deposition of zinc ions is realized in the electrolytic cell, and then the electrolytic product is subjected to solid-liquid separation by using a centrifugal machine to obtain zinc particle products, and the separated electrolyte is returned to an electrolysis rear liquid tank for recycling, and the zinc particles obtained by electrolysis are washed by using rinsing water to realize efficient separation of the zinc particles and residual electrolyte.

[0036] The zinc particles after centrifugation are washed by using rinsing water to realize efficient separation of the zinc particles and residual electrolyte.

[0037] The n-time rinsing device (n≥1) is a core container for multiple rinsing operations of the zinc-depleted scrap steel, and effectively removes residual impurities on the surface of the scrap steel through multiple rinsing; The conveying mechanism is connected with each zinc-depleting device and rinsing device, and is responsible for accurately conveying the scrap steel between the zinc-depleting devices to ensure smooth flow of the scrap steel in different processing stages; The rinsing liquid circulating unit is composed of a pump set and pipelines, the pump set is connected with the zinc-depleting tank through the pipelines to continuously supply and circulate sodium hydroxide solution to the zinc-depleting device, and further removes trace amounts of zinc and other impurities that may be left on the surface of the scrap steel by using the characteristics of the rinsing liquid, and reduces the use amount of the rinsing liquid by recycling.

[0038] The rinsed scrap steel enters the drying tank, and the rinsed scrap steel is dried by using a hot air convection method, and the temperature in the tank is maintained in the range of 50-400℃; The air blower continuously delivers dry air heated by the heater to the drying tank to ensure that the water on the surface of the scrap steel is evaporated to residual moisture ≤0.5%, and water vapor is discharged, and then the scrap steel is briquetted and output as clean scrap steel.

[0039] The tail gas is effectively purified by countercurrent contact with the spray absorption liquid in the tail gas washing tower.

[0040] It should be noted that: 1. The conveying devices are made of alkali-resistant metal, and the running speed is adjustable to adapt to different process cycle requirements; 2. The multiple zinc-depleting and rinsing devices are connected with fresh water sources and recycled rinsing water, respectively; The rinsing water is returned to the primary rinsing device for recycling after being purified by electrolysis; The rinsed steel is treated by using a drying device, and a hot air drying method is adopted; 3. Reverse flow supplement systems are respectively arranged between the n continuous zinc-depleting devices and the n continuous rinsing devices, when the zinc concentration of the leaching solution in the primary zinc-depleting device reaches the standard and is delivered to the liquid storage tank, the liquid level detection system sends a signal to start the conveying device to supplement the leaching solution in the secondary zinc-depleting device to the primary zinc-depleting device. The liquid level shortage of the subsequent i th zinc removal device (i is an integer from 1 to n-1) is sequentially supplemented by the zinc removal solution in the i+1 th device; The liquid level shortage of the n th zinc removal device is supplemented by the rinsing solution in the electrolysis post-liquid tank; The same principle is used for reverse fluid supplementation between the rinsing devices; The n th rinsing device is supplemented by tap water in the rinsing water tank; 4. The leaching solution is treated with lime reagent to generate calcium carbonate through precipitation reaction and regenerate sodium hydroxide, realizing the recycling of the alkali solution.

[0041] Example 3 When the incoming material is zinc-containing scrap steel 6.0 kg (150 mm x 50 mm x 1.5 mm, zinc layer thickness 55±2 μm), the device uses two consecutive zinc removal tanks and two consecutive rinsing tanks in series, the baskets are conveyed between the tanks by a mechanical hand, and the last rinsing tank is provided with tap water supply and is equipped with a rinsing water tank and a storage tank for backflow and water quality buffering.

[0042] The zinc removal solution is maintained at 90 ℃, and sodium hydroxide (NaOH) is added to each zinc removal tank to a mass concentration of 500 g / L.

[0043] At the same time, 200 Nm3 / (h·t) of micro-nano bubbles are introduced, the incoming material is sequentially fed into the zinc removal tank, and the residence time of each basket is controlled.

[0044] The zinc-removed baskets are sequentially fed into the rinsing tank, which is used for continuous circulation and backfeeding, and the last rinsing tank is supplied with tap water; the release criterion is that there is no visible alkali solution wall, no salt frost, and the wiping electrical conductivity is close to that of clean water.

[0045] Results: The zinc removal rate is 99.6%; the surface residual alkali is qualified; the mass concentration of zinc in the zinc removal solution is 60-75 g / L; this condition achieves a good compromise between reaction rate, chemical consumption and operation stability, and can be used as a reference condition for scale-up comparison.

[0046] Example 4 When the incoming material is zinc-containing scrap steel 10.0 kg (50 mm x 50 mm x 1.5 mm, zinc layer thickness 45±5 μm), the device uses three zinc removal tanks and three rinsing tanks in series, the baskets are conveyed between the tanks by a mechanical hand, and the last rinsing tank is equipped with a rinsing water tank.

[0047] The temperature of the solution was maintained at 80°C, sodium hydroxide (NaOH) was added to each zinc removal section to a mass concentration of 600 g / L, and micro-nano bubbles were introduced at 100 Nm3 / (h·t). The raw material was sequentially fed into the zinc removal tank. The zinc-removed basket was sequentially fed into the rinsing tank, and rinsing was performed by continuous backfeeding. The release criterion was that the surface had no visible alkali hanging wall, no salt frost, and the wiping electrical conductivity was close to the clean water background.

[0048] Results: The zinc removal rate was 99.9%; the surface residual alkali was qualified; the mass concentration of zinc in the solution after zinc removal was 70-74 g / L. This condition achieved a good compromise between reaction rate, reagent consumption, and operation stability, and can be used as a reference condition for scale-up comparison.

[0049] Example 5 The size of the zinc scrap to be treated was 150 mm x 50 mm, the thickness was 1.5 mm, and the thickness of the zinc layer on the surface was 50 ± 5 μm.

[0050] The feeding device used two zinc removal drums and two rinsing drums in series, and a tap water supply port was provided at the end, and a rinsing water tank and a storage tank were provided for backflow and water quality buffering.

[0051] The temperature of the leaching solution was maintained at 50°C, and sodium hydroxide (NaOH) was added to each section to a mass concentration of 600 g / L. The raw material was fed into the first zinc removal drum, stayed for a period of time, and then was transferred. The leaching solution was collected into the storage tank.

[0052] After zinc removal, the material was sequentially fed into three continuous rinsing drums, and continuous backfeeding was used. Tap water was supplied to the last rinsing drum; the release criterion was that the surface had no visible alkali hanging wall, no salt frost, and the wiping electrical conductivity was close to the clean water background.

[0053] Results: The zinc removal rate was 99.8%; the surface residual alkali was qualified; the mass concentration of zinc in the zinc removal solution reached the electrolysis requirement. This condition achieved a good compromise between reaction rate, reagent consumption, and operation stability, and can be used as a reference condition for scale-up comparison.

[0054] Example 6 The size of the zinc-containing scrap was 150 mm x 50 mm, the thickness was 1.5 mm, and the thickness of the zinc layer on the surface was 50 ± 3 μm.

[0055] The device was a continuous three-time zinc removal drum and a continuous three-time rinsing drum; a tap water supply port was provided at the end, and a rinsing water tank and a storage tank were provided for backflow and water quality / water quantity buffering.

[0056] The heating device and the heat preservation layer are used to maintain the dezincification liquid at 50 ℃; the sodium hydroxide is added in each section to make the mass concentration 500 g / L; the raw material is sequentially put into the dezincification roller; after the end of each section, it is transported again, and the dezincification section is collected into the storage tank.

[0057] The dezincified scrap steel sequentially enters 3 rinsing rollers, and is continuously returned; the end tap water supply is combined with the water tank electric conductivity threshold control; and the release criterion is that there is no visible alkali liquid wall hanging, no salt frost, and the wiping electric conductivity is close to the water background.

[0058] The above-described embodiments only express the preferred embodiments of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications, improvements and substitutions can be made, which belong to the protection scope of the present application.

Claims

1. A complete equipment for recycling zinc-containing scrap steel, characterized in that, Comprise: A dezincification system module, a purification system, an electrolysis system, a zinc particle washing system, a rinsing system, a drying system, and a tail gas treatment system; The dezincification system is used for dezincification treatment of zinc-containing scrap steel according to an alkaline leaching system to realize recovery of the zinc-containing scrap steel; The purification system is used for purification of dezincification alkali liquor; The electrolysis system is used for electrolytic zinc extraction; The zinc particle washing system is used for washing of zinc particles; The rinsing system is used for rinsing of scrap steel; The drying system is used for drying of scrap steel; The tail gas treatment system is used for washing and recovery of tail gas, and the dezincification process is strengthened by controlling the concentration of sodium hydroxide, leaching temperature, and micro-nano bubble flow rate.

2. The complete equipment for recycling zinc-containing scrap steel according to claim 1, characterized in that, The dezincification system comprises: A feeding unit for feeding zinc-containing scrap steel into the dezincification system; A plurality of continuous dezincification devices for sequentially dezincifying the zinc-containing scrap steel in an alkaline system; A leaching solution circulating unit comprising a pump set and pipelines for supplying and circulating sodium hydroxide solution to the dezincification baskets; A micro-nano bubble generator for improving the dispersibility of air, oxygen-enriched air, and industrial oxygen by using micro-nano bubbles, and for synergistically strengthening the dezincification process by efficient oxygen supply, interface activation, and hydroxyl radicals generated during collapse; A post-electrolysis solution tank for recovering and storing the electrolysis solution, which can make up the liquid level deficiency of the last dezincification device; A heating and temperature control unit for maintaining the dezincification liquid temperature in the range of 20-95℃. The dezincification devices are a plurality of continuous dezincification baskets connected with dezincification tanks or a plurality of continuous dezincification rollers connected in series, which are used for continuous dezincification of zinc-containing scrap steel in an alkaline system; 3. The complete equipment for recycling zinc-containing scrap steel according to claim 2, characterized in that, The dezincification baskets adopt a crane, mechanical gripper conveying mechanism for conveying scrap steel between the dezincification tanks; The dezincification rollers adopt a plate chain conveying mechanism for conveying scrap steel between the rollers; An alkali liquor continuous replenishment system is provided between the plurality of continuous dezincification devices, and the working mode comprises: When the leaching solution in the first dezincification device is pumped to the solution storage tank due to reaching the target zinc concentration, the liquid level detector sends a signal to start the pump set to replenish the leaching solution in the second dezincification device to the first dezincification device; The liquid level deficiency of the subsequent i-th dezincification device is continuously replenished by the solution in the i+1-th dezincification device; The liquid level deficiency of the last dezincification device is replenished by the post-electrolysis solution tank or scrap steel rinsing water. The purification system comprises:

4. The complete equipment for recycling zinc-containing scrap steel according to claim 1, characterized in that, A stirred tank for generating CaCO3 and NaOH by stirring and reacting with lime in the leaching solution, realizing regeneration and recycling of sodium hydroxide solution; A filter press for solid-liquid separation of the decarburized leaching solution, trapping calcium carbonate precipitate and suspended solids, and making the solution entering the electrolysis process meet the process requirements in terms of cleanliness. The electrolysis system uses stainless steel as anode and lead-calcium-tin composite electrode as cathode, and comprises:

5. The complete equipment for recycling zinc-containing scrap steel according to claim 1, characterized in that, A pre-electrolysis liquid tank for storing the purified zinc-containing leaching solution and realizing quantitative delivery to the electrolysis tank through a liquid level controller; An electrolysis tank for realizing electrochemical deposition of zinc ions; A centrifuge for solid-liquid separation of electrolysis products to obtain zinc particle products, and the separated electrolyte returns to the post-electrolysis solution tank for recycling; ​ Rinse water is used to wash the zinc particles obtained by electrolysis, so as to realize efficient separation of the zinc particles and residual electrolyte.

6. The complete equipment for recycling zinc-containing scrap steel according to claim 1, characterized in that, The rinse system comprises: A plurality of continuous rinse devices for rinsing the zinc-depleted scrap steel multiple times; A rinse liquid circulating unit comprising a pump set and pipelines, which is used to supply and circulate the sodium hydroxide solution to the electrolysis tank.

7. The complete equipment for recycling zinc-containing scrap steel according to claim 6, characterized in that, The rinse devices in the rinse system are n continuous rinse baskets connected with rinse tanks or n continuous rinse drums connected in series, which are used to continuously rinse the zinc-containing scrap steel in an alkaline system; The rinse baskets adopt a crane and mechanical gripper conveying mechanism, which is used to convey the scrap steel between the rinse tanks; The rinse drums adopt a plate chain conveying mechanism, which is used to convey the scrap steel between the drums; An alkali liquid continuous supplement system is arranged between the plurality of continuous rinse devices, and the working mode comprises: When the leaching liquid in the first rinse device is pumped to the liquid storage tank due to reaching the target zinc concentration, the liquid level detector sends a signal to start the pump set to supplement the leaching liquid in the second rinse device to the first rinse device; The liquid level vacancy of the subsequent i-th rinse device is continuously supplemented by the solution in the i+1-th rinse device; The liquid level vacancy of the last rinse device is supplemented by fresh tap water.

8. The complete equipment for recycling zinc-containing scrap steel according to claim 1, characterized in that, The drying system comprises: A drying tank for drying the rinsed scrap steel by using a hot air convection method, and the temperature in the tank is maintained in the range of 50-400℃; An air blower for continuously conveying the drying air heated by the heater to the drying tank, and the air speed is controlled in the range of 2-5m / s, so as to ensure that the water on the surface of the scrap steel is evaporated to residual moisture≤0.5%, and the water vapor is discharged.

9. The complete equipment for recycling zinc-containing scrap steel according to claim 1, characterized in that, The tail gas treatment system comprises: A tail gas washing tower for purifying the sodium hydroxide in the waste gas by countercurrent contact between the spray absorption liquid and the waste gas.

10. The application method of a complete set of equipment for recycling zinc-containing scrap steel resources, characterized in that, The application method realizes the contents of the zinc-containing scrap steel resource utilization complete equipment according to claims 1-9, and the specific steps comprise: Step 1: The zinc-containing scrap steel enters the n times of zinc-depleted devices in sequence through the conveying mechanism, and is subjected to zinc depletion in the sodium hydroxide solution with micro-nano bubbles; Step 2: The leaching liquid is subjected to lime stirring treatment and then enters the electrolysis system to recover zinc; Step 3: The electrolyte is subjected to electrolysis centrifugation and then is used in reflux circulation; Step 4: The zinc-depleted scrap steel enters the n times of rinse devices and is subjected to rinsing in sequence; Step 5: The rinsed scrap steel is dried and briquetted, and is output as clean scrap steel; Step 6: The tail gas is purified by countercurrent contact with the spray absorption liquid in the tail gas washing tower, so as to purify the sodium hydroxide in the waste gas.

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