A metal liquid depth oil removal and TOC removal system and process

Abstract

The embodiment of the present application discloses a kind of metal material liquid depth oil removal and TOC system and process, belong to metal extraction material liquid purification processing technical field.Metal material liquid depth oil removal and TOC system include the pre-oil removal unit, depth oil removal unit, depth TOC removal unit sequentially interconnected setting.The present application is pre-oil removal, depth oil removal of alternate carbon filter, countercurrent catalytic oxidation removal TOC, effluent oil content <1 mg / L, TOC 10~80 mg / L, ORP fluctuation is small, does not affect subsequent electrodeposition and ternary precursor production, with the advantages of less activated carbon dosage, low operating cost, strong stability etc., suitable for nickel cobalt manganese sulfate, nickel cobalt manganese chloride extraction liquid purification.

Description

Technical Field

[0001] This invention relates to the field of metal extraction liquid purification technology, specifically to a system and process for deep oil and TOC removal from metal liquids, and more specifically, to a system and process for deep oil and TOC removal from acidic, warm, and high-salt metal liquids. Background Technology

[0002] In the process of extracting and purifying nickel, cobalt, and manganese in the ternary cathode industry, organic matter and oily substances such as P204, P507, C272, and solvent oil may be introduced into the molten metal. These impurities will affect the production quality of subsequent ternary precursors. This molten metal is used in the electrowinning process, which requires a higher content of organic matter in the molten metal. Organic matter and oil will increase the energy consumption of the electrowinning process, affect the quality of the metal products, and cause problems such as porosity and blackening.

[0003] Currently, conventional treatment processes mainly include a combination of pre-degreasing and resin adsorption, as well as activated carbon adsorption. Among these, resin adsorption is effective in removing oily substances, but due to its limited adsorption capacity, it is difficult to achieve deep removal of total organic carbon (TOC). Activated carbon adsorption generally suffers from problems such as large activated carbon dosage, inability to regenerate, and high operating costs. Furthermore, during conventional mixing, there are dead zones in the mixing process, leading to uneven contact between activated carbon and the feed liquid, resulting in the inability to consistently achieve the required TOC levels. The core of conventional catalytic oxidation processes relies on hydroxyl radicals to oxidize and degrade organic matter. Under neutral or weakly alkaline conditions, ozone decomposition and the generation of hydroxyl radicals are more easily triggered. However, for acidic, high-salt, and high-temperature metal slurry systems, the acidic environment inhibits the generation rate of hydroxyl radicals, causing ozone direct oxidation to become the dominant process, thus reducing its oxidation effect. In high-salt systems, salt ions easily quench hydroxyl radicals, while high temperatures accelerate ozone decomposition and reduce the solubility of ozone in the system. Therefore, conventional processes have limited effectiveness in degrading TOC in acidic, high-salt, and high-temperature systems, especially in metal salt slurry systems, where transition metals catalyze ozone decomposition, resulting in even worse effects.

[0004] Therefore, there is an urgent need to develop a process for deep oil and TOC removal from metal feed solutions in acidic extraction systems, achieving the treatment target of oil <1 mg / L and TOC 10~80 mg / L, while not affecting the subsequent electrowinning process, not causing significant changes in redox potential, and having the advantages of low cost and stable operation.

[0005] Chinese patent CN208561957U discloses a system for deep COD removal from nickel-cobalt raffinate, comprising a pre-degreasing system, a deep degreasing system, and a deep COD removal system, which can achieve a COD < 80 mg / L treatment target. However, this system is mainly for raffinate with sodium sulfate as the main component, which is quite different from the metal liquid system. Although the initial pH is acidic (pH=4~5), in the resin degreasing and ozone catalytic oxidation process, sulfuric acid needs to be added first to adjust the pH to 2 to match the pH of the resin degreasing inlet, so as to improve the degreasing effect. Then, sodium hydroxide is added to adjust the pH to 7 to avoid the inhibition and quenching of hydroxyl radicals under acidic conditions, resulting in high reagent costs and a relatively complex process route.

[0006] Chinese patent CN223592553U discloses a P507 raffinate oil and COD removal system, comprising a pretreatment system, a filtration system, and an oxidation system. The pretreatment system adjusts the pH by adding sodium hydroxide, changing the original acidic environment of the raffinate into an alkaline system. However, its applicability to acidic systems is not mentioned. Furthermore, for metal feed systems, adding sodium hydroxide causes metal precipitation; therefore, this system is not suitable for the deep degradation of TOC in acidic metal feed systems.

[0007] Chinese patent CN117265600A discloses a nickel sulfate solution degreasing process for electrolytic nickel deposition. This process combines coalescing resin with deep adsorption, achieving a treatment target of oil content <1 mg / L and TOC <60 mg / L. The key challenge of this process is addressing the impact of residual surfactants on the TOC of the system during electrolytic nickel deposition. The ORZ resin used achieves a TOC <60 mg / L through deep adsorption of surfactants. However, for extraction systems without added surfactants, the effluent TOC is high, which is limited by the resin's adsorption capacity and pore structure, making deep TOC removal difficult. Furthermore, resin regeneration requires solvents such as methanol and ethanol, which involves Class A explosion-proof requirements and necessitates specific site conditions, making it difficult for widespread adoption by enterprises. Summary of the Invention

[0008] Therefore, embodiments of the present invention provide a system and process for deep degreasing and TOC removal of metal slurry, which achieves simultaneous deep removal of oil and TOC, is suitable for acidic, high-temperature, and high-salt metal slurry, does not affect the electrowinning process, and has the advantages of low operating cost and high stability.

[0009] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0010] According to a first aspect of the present invention, the present invention provides a deep degreasing and TOC removal system for molten metal, comprising a pre-degreasing unit, a deep degreasing unit, and a deep TOC removal unit arranged sequentially in connection with each other;

[0011] The pre-oil removal unit includes a pre-oil removal inlet pump, a coalescing adsorption column, an oil-water separator, and a coalescing outlet tank connected in sequence.

[0012] The deep oil removal unit includes an activated carbon addition tank pump, activated carbon addition tank I, plate and frame carbon filter I, activated carbon addition tank II, and plate and frame carbon filter II connected in sequence. The inlet of the activated carbon addition tank pump is connected to the outlet of the coalescing water outlet tank, the outlet of the activated carbon addition tank pump is connected to the inlet of the activated carbon addition tank II, and the outlet of the plate and frame carbon filter II is connected to the inlet of the activated carbon addition tank I, forming a two-stage activated carbon addition and alternating plate and frame carbon filtration circulation structure.

[0013] The deep TOC removal unit includes a catalytic tower inlet tank, a catalytic tower inlet pump, a pipeline mixer, and a catalytic oxidation tower connected in sequence. The pipeline mixer is connected in sequence to a liquid oxidant dosing pump and a liquid oxidant storage tank. An aeration component is provided at the bottom of the catalytic oxidation tower and is connected to an ozone generating unit. The inlet of the catalytic tower inlet tank is connected to the outlets of plate and frame carbon filter I and plate and frame carbon filter II, respectively.

[0014] Furthermore, the catalyst loading zone is provided in the middle section of the catalytic oxidation tower. The catalyst loading zone is filled with a packing body composed of multiple corrugated plates stacked together. The surface of the packing body is loaded with a catalyst. The corrugated plates are evenly distributed with diamond-shaped openings. The edges of the diamond-shaped openings are folded upward to form an orifice plate. The diamond-shaped openings on adjacent corrugated plates are staggered.

[0015] Furthermore, the inclination angle of the corrugated plate is 30°~45°;

[0016] The longitudinal dimension of the diamond-shaped opening is 15~20 mm, and the short dimension is 12~15 mm;

[0017] The height of the perforated plate is 5~8 mm;

[0018] The thickness of the packing body is 1 / 3 to 2 / 3 of the effective liquid height inside the tower;

[0019] The catalyst is a Ni-Ce composite oxide, with a molar ratio of Ni to Ce of 4~8:1;

[0020] The catalyst loading is 1~10 g / m³. 2 .

[0021] Furthermore, the catalytic oxidation tower is a vertical cylindrical structure with a height-to-diameter ratio of 3:1 to 10:1, an outer diameter of less than 3m, an effective liquid height of less than 7m, and the tower body is made of 316L stainless steel or higher grade corrosion-resistant stainless steel.

[0022] Furthermore, the system also includes a catalytic tower outlet tank, and the outlet of the catalytic oxidation tower is connected to the catalytic tower outlet tank via an Ω-shaped pipe.

[0023] According to a second aspect of the present invention, the present invention provides a deep degreasing and TOC removal process for molten metal based on the system described in any of the preceding claims, the process comprising:

[0024] (1) The metal liquid is fed into the coalescence adsorption column for coalescence and oil removal by the pre-oil removal feed pump, and then enters the oil-water separator for static stratification. After stratification, the lower layer of water is discharged into the coalescence water outlet tank.

[0025] (2) The effluent from the coalescence effluent tank is pumped into the deep oil removal unit through the activated carbon addition tank inlet pump. Deep oil removal is carried out by two-stage activated carbon addition and alternating plate and frame carbon filtration to obtain deep oil-removed effluent.

[0026] (3) The deep oil removal water enters the catalytic tower inlet tank and is sent to the pipeline mixer by the catalytic tower inlet pump. At the same time, the liquid oxidant is sent to the pipeline mixer by the liquid oxidant dosing pump. After mixing, it is sent to the catalytic oxidation tower and undergoes countercurrent catalytic oxidation with the ozone supplied by the ozone generation unit to obtain a feed liquid with an oil content of <1mg / L and a TOC content of 10~80mg / L.

[0027] Furthermore, in step (1),

[0028] The metal feed solution is one or a mixture of nickel cobalt manganese sulfate extract and nickel cobalt manganese chloride extract.

[0029] The metal molten metal has a pH of 2-6, a temperature of 20-80℃, and a metal ion concentration of >40 g / L;

[0030] The packing material of the coalescing adsorption column is coalescing resin or coalescing fiber, and the influent flow rate is 2~7.5 BV / h;

[0031] The residence time of the oil-water separator is 1-4 hours, and the residence time of the coalescing water tank is 1-2.5 hours.

[0032] Furthermore, in step (2), the specific process of adding the two-stage activated carbon and alternating plate and frame carbon filtration is as follows:

[0033] The effluent from the coalescing effluent tank is pumped into the activated carbon addition tank II via the activated carbon addition tank inlet pump. Activated carbon is added into the activated carbon addition tank II and mixed thoroughly. The effluent is then filtered through the plate and frame carbon filter II to form an activated carbon filter cake. The effluent then enters the depth TOC removal unit.

[0034] The next batch of water from the coalescing effluent tank is pumped into activated carbon addition tank II via the activated carbon addition tank inlet pump. No activated carbon is added. The water is filtered through plate and frame carbon filter II using the activated carbon cake formed in the previous batch. The effluent then enters activated carbon addition tank I, where activated carbon is added and thoroughly mixed. The water is then filtered through plate and frame carbon filter I to form a new activated carbon cake. The effluent then enters the deep TOC removal unit. At the same time, the old filter cake is removed from plate and frame carbon filter II.

[0035] In subsequent batches, the effluent from the coalescence tank is pumped into activated carbon addition tank I without adding activated carbon. The effluent then passes through plate and frame carbon filter I using the activated carbon cake formed in the previous batch. The effluent then enters activated carbon addition tank II, where activated carbon is added and thoroughly mixed. The effluent then passes through plate and frame carbon filter II to form a new activated carbon cake. The effluent then enters the deep TOC removal unit. At the same time, the old filter cake is removed from plate and frame carbon filter I. This cycle repeats.

[0036] Furthermore, the activated carbon is fruit shell carbon or coal-based carbon with a particle size of 2-500 mesh;

[0037] During the initial operation, the activated carbon dosage is 0.5~4‰ (W / V), and during subsequent alternating operation, the activated carbon dosage is 0.2~2‰ (W / V).

[0038] Furthermore, in step (3),

[0039] The liquid oxidant includes hydrogen peroxide with a mass concentration of 28-35% and sodium persulfate aqueous solution with a mass concentration of 8-10 mmol / L, and the dosage is 0.2-5‰ (V / V).

[0040] The conditions for catalytic oxidation are as follows: feed temperature is 20~80℃, ozone concentration is 100~200mg / L, ozone dosage to influent TOC mass ratio is 2~15, and the residence time of feed in the catalytic oxidation tower is 0.5~3 h.

[0041] The embodiments of the present invention have the following advantages:

[0042] 1. It can achieve simultaneous removal of oil and TOC from the feed solution in the extraction system, meeting the processing requirements of electrowinning and ternary products for oil <1 mg / L and TOC <80 mg / L.

[0043] 2. The combination of Ω pipe and gas-liquid countercurrent contact can maintain the reaction boundary inside the tower, allowing for full gas-liquid contact, improving ozone utilization, and reducing the O / T ratio of the system.

[0044] 3. For the metal feed system, the overall design takes into account the effects of feed density, oxide residue, etc. In addition to ensuring the indicators of oil and TOC in the effluent, the system has a better match in terms of tower height, ozone generator concentration, ozone residue, etc. When the effluent of the subsequent system is used for the electrowinning system, it will not have an adverse effect on the oxidation-reduction potential, energy consumption, or electrowinning nickel products of the electrowinning system.

[0045] 4. The two-stage alternating circulation design of the plate carbon filter device can improve the removal efficiency of activated carbon for oily organic matter, and reduce the amount of activated carbon used and operating costs.

[0046] 5. Through comprehensive consideration of overall process design, parameter control, and equipment design, the removal effect of TOC can be guaranteed under acidic conditions at temperatures of 20~80℃, without interference from metal ions in the system on the catalytic oxidation effect, and without causing metal loss. Due to reasonable control of the O / T ratio and reaction rate, the increase in effluent oxidation-reduction potential is <70mV, which will not affect the subsequent electrowinning process.

[0047] 6. The system is automatically controlled with a high degree of automation, saving labor costs. It also has a reserved AI interface, which provides room for future intelligent debugging. Attached Figure Description

[0048] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0049] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0050] Figure 1 This is a schematic diagram of the structure of the deep degreasing and TOC removal system for molten metal provided by the present invention;

[0051] Figure 2 This is a schematic diagram of the structure of the catalytic oxidation tower provided by the present invention;

[0052] Figure 3 This is a schematic diagram of the structure of the corrugated plate provided by the present invention;

[0053] Figure 4This is a schematic diagram of the structure of the packing body provided by the present invention;

[0054] In the diagram: 1-Pre-oil removal inlet pump; 2-Coalescing oil removal column; 3-Oil-water separator; 4-Oil storage tank; 5-Coalescing water outlet tank; 6-Deep oil removal inlet pump; 7-Activated carbon dosing tank I; 8-Plate and frame carbon filter I; 9-Activated carbon dosing tank II; 10-Plate and frame carbon filter II; 11-Catalytic tower inlet tank; 12-Catalytic tower inlet pump; 13-Liquid mixer; 14-Catalytic oxidation tower; 15-Liquid oxidant dosing pump; 16-Liquid oxidant storage tank; 17-Refrigerated dryer; 18-Molecular sieve I; 19-Molecular sieve II; 20-Ozone generator; 21-Heat exchanger; 22-Packaging body; 23-Corrugated plate; 24-Rhomboid opening; 25-Perforated plate. Detailed Implementation

[0055] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] See Figure 1 The present invention provides a deep degreasing and TOC removal system for molten metal, comprising a pre-degreasing unit, a deep degreasing unit and a deep TOC removal unit connected in sequence by pipelines.

[0057] The pre-oil removal unit includes a pre-oil removal inlet pump 1, a coalescing adsorption column 2, an oil-water separator 3, an oil storage tank 4, and a coalescing water outlet tank 5. The pre-oil removal inlet pump 1, the coalescing adsorption column 2, and the oil-water separator 3 are connected sequentially through pipelines along the direction of liquid flow. The oil storage tank 4 and the coalescing water outlet tank 5 are respectively connected to the top oil outlet and the bottom liquid outlet of the oil-water separator 3.

[0058] The metal feed solutions processed by this invention mainly include acidic extraction systems such as nickel-cobalt-manganese sulfate solutions and nickel-cobalt-manganese chloride solutions. These solutions can be either single-component solutions or mixed solutions containing multiple components. In some specific embodiments, the metal ion concentration in the feed solution is >40 g / L, TOC = 300~500 mg / L, oil content is 30~500 mg / L, pH = 2~6, and temperature is 20~80℃.

[0059] The coalescing adsorption column 2 is used to coalesce dispersed oil and emulsified oil droplets in the molten metal feed. In some specific embodiments, the coalescing packing material inside the coalescing adsorption column is coalescing resin and / or coalescing fiber. Coalescing resin refers to a polymer material with coalescing function; for example, OCZ resin from Beijing Saikekanglun Environmental Protection Technology Co., Ltd. can be used. Coalescing fiber refers to coalescing fiber balls, coalescing fiber cloth, coalescing fiber filaments, etc. The oil-water separator 3 is used to allow the feed liquid treated by the coalescing adsorption column 2 to undergo oil-water separation. In some specific embodiments, the oil-water separator 3 adopts a two-stage structure: the front stage is used for homogenization and stabilization of the feed liquid, and the rear stage is used for gravity oil-water separation, so that the oil phase floats fully and the water phase sinks stably, achieving a better oil-water separation effect.

[0060] In some specific embodiments, the coalescing adsorption column 2 adopts a bottom-in, top-out material flow direction. The metal liquid enters from the bottom of the coalescing adsorption column 2, is adsorbed by the coalescing packing, and flows out from the top. When the liquid enters the oil-water separator 3, it adopts a bottom feeding method, that is, the connecting pipe extends to the bottom of the liquid surface of the oil-water separator 3 to avoid the impact of the feeding and damage to the already formed oil-water separation interface, thereby improving the separation efficiency.

[0061] In some specific embodiments, the inlet flow rate of the coalescing adsorption column 2 is controlled at 2~7 BV / h, the residence time of the liquid in the oil-water separator 3 is controlled at 1~4 h, and the residence time of the liquid in the coalescing outlet tank 5 is controlled at 1~2.5 h, so as to achieve stable operation of the pre-oil removal unit.

[0062] The molten metal feed enters the pre-oil removal unit, where it is pumped by the pre-oil removal feed pump 1 to the lower end of the coalescing adsorption column 2. This column agglomerates the fine dispersed oil and emulsified oil droplets in the feed into larger oil droplets, while simultaneously preliminarily adsorbing some large organic molecules. After treatment, the feed flows out from the upper end of the coalescing adsorption column 2 and enters the oil-water separator 3 for settling and stratification. The upper oil phase overflows from the upper outlet of the oil-water separator 3 and is discharged to the oil storage tank 4 for subsequent reuse or harmless disposal. The lower layer, after preliminary oil removal, enters the coalescing effluent tank 5 for buffering before being pumped to the deep oil removal unit. After treatment by the pre-oil removal unit, the oil content in the effluent is stabilized at 10–55 mg / L, and the TOC is less than 300 mg / L.

[0063] The deep oil removal unit includes an activated carbon dosing tank inlet pump 6, activated carbon dosing tank I 7, plate and frame carbon filter I 8, activated carbon dosing tank II 9, and plate and frame carbon filter II 10, which are connected in sequence by pipelines. The inlet of the activated carbon dosing tank inlet pump 6 is connected to the outlet of the coalescence outlet tank 5 via a pipeline, and its outlet is connected to the inlet of activated carbon dosing tank II 9 via a pipeline. The outlet of plate and frame carbon filter II 10 is connected to the inlet of activated carbon dosing tank I 7 via a pipeline. The outlets of plate and frame carbon filters I 8 and II 10 are respectively connected to the deep TOC removal unit (catalytic tower inlet tank 11) via pipelines. The effluent from the pre-degreasing unit is pumped into the deep degreasing unit via the activated carbon addition tank inlet pump 6. It employs a two-stage alternating circulation filtration structure consisting of plate and frame carbon filter I 8 and plate and frame carbon filter II 10. Through a cycle of carbon addition to form filter cake, reuse of filter cake, and cake removal for renewal, deep degreasing of the molten metal is achieved. The specific operation process is as follows:

[0064] Initial operation: Water from coalescing effluent tank 5 enters activated carbon addition tank II 9 via activated carbon addition tank inlet pump 6. Activated carbon is added to activated carbon addition tank II 9. After stirring to fully mix the liquid with the activated carbon, the water enters plate and frame carbon filter II 10 for filtration. Activated carbon filter cake is formed on the surface of the plate and frame filter cloth. The effluent then enters the next unit (depth excluding TOC unit).

[0065] Alternating operation: The next batch of water from coalescing effluent tank 5 enters activated carbon addition tank II 9 via activated carbon addition tank inlet pump 6 without adding activated carbon. The liquid directly enters plate and frame carbon filter II 10, where it is filtered using the activated carbon filter cake formed in the previous batch. The effluent then enters activated carbon addition tank I 7 where activated carbon is added. After stirring and mixing, it is filtered again through plate and frame carbon filter I 8 to form a new activated carbon filter cake. The effluent then enters the next unit (depth excluding TOC unit), while the old filter cake is removed from plate and frame carbon filter II 10.

[0066] Cyclic Switching: In subsequent batches, the effluent from coalescing tank 5 is pumped into activated carbon dosing tank I 7 (without added activated carbon) via activated carbon dosing tank inlet pump 6. The activated carbon cake from plate and frame carbon filter I 8 is reused for filtration. The effluent then enters activated carbon dosing tank II 9, where activated carbon is added, and is filtered through plate and frame carbon filter II 10. The effluent then enters the next unit (depth excluding TOC units), while the cake from plate and frame carbon filter I 8 is unloaded. The next batch then switches to reusing the cake from plate and frame carbon filter II 10, adding activated carbon to activated carbon dosing tank II 7 to form a cake, while simultaneously unloading the old cake from plate and frame carbon filter II 10. This cycle repeats continuously, achieving stable operation.

[0067] In some specific embodiments, the pore size of the filter cloth in plate and frame carbon filter I and plate and frame carbon filter II is ≤25 micrometers, the plate and frame pressure is ≤0.65 MPa, and the filtration flow rate is 0.3~0.6 m / s. 3 / (m 2 (·h). It can achieve the filtration precision of activated carbon while ensuring the throughput of secondary filtration.

[0068] In some specific embodiments, the activated carbon is selected from fruit shell charcoal and / or coal-derived charcoal. Fruit shell charcoal refers to coconut shell activated carbon, walnut shell activated carbon, etc.; coal-derived charcoal refers to anthracite activated carbon, bituminous coal activated carbon, lignite activated carbon, etc. The difference between fruit shell charcoal and coal-derived charcoal lies in their source. Fruit shell charcoal originates from biomass carbon materials, processed from fruit shells, and has a higher iodine value, exhibiting strong adsorption performance for small molecules. Coal-derived charcoal, on the other hand, is obtained through deep processing of raw coal, has a slightly lower iodine value than fruit shell charcoal, and is more effective at removing large organic molecules. Activated carbon is available in powder (typically 200-500 mesh) or granular form (typically <100 mesh).

[0069] In some specific embodiments, during the initial run, the activated carbon dosage is controlled at 0.5~4‰ (W / V, i.e., 0.5~4g of activated carbon per 1000mL of feed solution), and during the remaining alternating run stages, the activated carbon dosage is controlled at 0.2~2‰ (W / V).

[0070] The above-mentioned two-stage alternating filtration mode can achieve excellent deep oil removal effect, so that the oil content of the treated water is less than 5 mg / L and the TOC content is less than 170 mg / L, which meets the feeding requirements of the subsequent deep TOC removal unit. At the same time, the single-addition and double-use of activated carbon mode effectively reduces the consumption of activated carbon, lowers the system operating cost, and balances treatment effect and economy.

[0071] The deep TOC removal unit includes a catalytic tower inlet tank 11, a catalytic tower inlet pump 12, a pipeline mixer 13, and a catalytic oxidation tower 14, which are connected in sequence via pipelines. The pipeline mixer 13 is connected in sequence via pipelines to a liquid oxidant dosing pump 15 and a liquid oxidant storage tank 16. The bottom of the catalytic oxidation tower 14 is equipped with an aeration assembly (not shown in the figure), which is connected to the ozone generation unit. The inlet of the catalytic tower inlet tank 11 is connected via pipelines to the outlets of plate and frame carbon filter I 8 and plate and frame carbon filter II 10, respectively.

[0072] The deep-de-oiled effluent enters the catalytic tower inlet tank 11 for buffering and is then pumped into the pipeline mixer 13 by the catalytic tower inlet pump 12. Simultaneously, the liquid oxidant in the liquid oxidant storage tank 16 is pumped into the pipeline mixer 13 by the catalytic tower inlet pump 15. After the feed liquid and liquid oxidant are fully mixed, they enter the tower from the top of the catalytic oxidation tower 14. Ozone generated by the ozone generation unit is fed into the catalytic oxidation tower 14 from the bottom through the aeration component, forming a counter-current contact with the feed liquid flowing from top to bottom in the tower. Under the action of the catalyst inside the catalytic oxidation tower 14, a synergistic catalytic oxidation reaction occurs, mineralizing and degrading the residual organic matter in the feed liquid. The tail gas generated after the reaction is discharged from the top of the catalytic oxidation tower 14, enters the tail gas destruction device for treatment to meet the standards, and is then discharged. The treated feed liquid is discharged from the bottom of the catalytic oxidation tower 14.

[0073] The liquid oxidant storage tank 16 contains liquid oxidant. In some specific embodiments, the liquid oxidant is hydrogen peroxide with a mass concentration of 28-35% or sodium persulfate aqueous solution with a mass concentration of 8-10 mmol / L, and the dosage is 0.2-5‰ (V / V, that is, 0.2-5 mL of liquid oxidant is added per 1000 mL of feed solution).

[0074] See Figure 2-4 The catalytic oxidation tower 14 used in this invention has a catalyst loading zone in the middle section. The catalyst loading zone is filled with a packing body 22 composed of multiple corrugated plates stacked together. The surface of the packing body 22 is loaded with a catalyst (not shown in the figure). Each corrugated plate 23 has diamond-shaped openings 24 evenly distributed on it. The edges of the diamond-shaped openings 24 are folded upward to form an orifice plate 25. The orifice plate 25 can effectively maintain a certain liquid level in the tower and prolong the residence time of the liquid. The diamond-shaped openings on two adjacent corrugated plates are staggered.

[0075] In some specific embodiments, the inclination angle of the corrugated plate 23 (the angle formed by the corrugated inclined surface and the horizontal direction) is 30°~45°, the longitudinal dimension of the rhomboid opening 24 is 15~20 mm, the short dimension is 12~15 mm, the height of the orifice plate is 5~8 mm, and the thickness of the packing body 22 is 1 / 3~2 / 3 of the effective liquid height in the tower. The rhomboid openings and staggered arrangement of the packing can increase the gas-liquid cutting frequency, improve the solubility and dispersibility of ozone in the feed liquid, make the gas-liquid contact more sufficient, improve the utilization rate of ozone, reduce the residue of ozone and oxidant, and reduce the increase in effluent ORP.

[0076] In some specific embodiments, the Ni-Ce composite oxide is NiO-CeO2, wherein the Ni:Ce (molar ratio) is 4~8:1, and the loading is 1~10 g / m³. 2 This catalyst possesses the dual functions of enhancing gas-liquid contact and catalytic oxidation. The catalyst loading provides a reaction interface for the generation of hydroxyl radicals from ozone decomposition. The catalytic effect of the catalyst can accelerate the generation rate of hydroxyl radicals, to a certain extent offsetting their decomposition and quenching rates, thus ensuring the degradation effect of organic matter.

[0077] This invention employs ozone catalytic oxidation technology. Through aeration, ozone bubbles are highly dispersed, and the repeated cutting action of the packing material on both the gas and liquid phases further enhances the solubility and dispersibility of ozone in the feed solution, resulting in more thorough gas-liquid contact. Simultaneously, the addition of a liquid oxidant replenishes the number of free radicals in the system (hydrogen peroxide introduces hydroxyl radicals, and persulfate introduces sulfate radicals), mitigating to some extent the weakened oxidation capacity caused by the quenching and destruction of already generated free radicals under acidic, high-temperature, and high-salt conditions. The synergistic effect of these processes ensures a deep removal of TOC from the system.

[0078] In some specific embodiments, the catalytic oxidation tower 14 is a vertical cylindrical structure with a height-to-diameter ratio of 3:1 to 10:1, an outer diameter of less than 3 m, and an effective liquid depth of less than 7 m. The hydraulic residence time of the feed liquid in the catalytic oxidation tower 14 is controlled to be 0.5 to 3 hours to ensure that the organic matter is fully mineralized and degraded. The tower body is made of acid-resistant, temperature-resistant, and corrosion-resistant materials of 316L stainless steel or higher grade to extend the service life of the equipment.

[0079] In some specific embodiments, the top of the catalytic oxidation tower 14 is equipped with a water spraying system, which has the dual functions of uniform water distribution and foam breaking: on the one hand, it can uniformly spray the liquid from the pipeline mixer 13 onto the catalyst loading area to ensure that the liquid is in full contact with the catalyst and ozone; on the other hand, it can break the foam generated during the reaction to prevent the foam from carrying the liquid into the tail gas system and ensure operational stability.

[0080] Ozone is produced and provided by an ozone generating unit. In some specific embodiments, the ozone generating unit includes a refrigerated dryer 17, molecular sieve I 18, molecular sieve II 19, an ozone generator 20, and a heat exchanger 21, which are connected in sequence by pipes. Compressed air used in enterprise production is dried by the refrigerated dryer 17, and then purified by two stages of molecular sieves before entering the ozone generator 20 to produce ozone. The ozone generator 20 uses internal and external circulating water for cooling. The external circulating water is cooled by heat exchanger 21 and cooling unit before being recycled to ensure the long-term stable operation of the ozone generator 20.

[0081] In some preferred embodiments, the outlet pipe of the ozone generator 20 extends beyond the top of the catalytic oxidation tower 14 before connecting downwards to the aeration assembly at the bottom of the catalytic oxidation tower 14. This structure utilizes the height difference to form a liquid seal, effectively preventing the liquid material in the catalytic oxidation tower 14 from flowing back into the ozone generator, thus avoiding damage to the equipment and ensuring its safe operation. The aeration assembly is selected from one of the following: titanium microporous aeration head, perforated pipe aerator, jet aerator, micro / nano aerator, or nano cavitation aerator, and can be flexibly chosen according to the ozone utilization rate requirements.

[0082] In some preferred embodiments, the ozone generator 20 is selected as a plate type or a tubular type: the ozone concentration prepared by the tubular ozone generator is 100~150 mg / L, and the ozone concentration prepared by the plate ozone generator is 100~200 mg / L; the mass ratio of ozone dosage to TOC in the feed liquid (O / T) is controlled at 2~15 to ensure that the ozone is fully dissolved and participates in the catalytic oxidation reaction, thereby improving the TOC degradation effect.

[0083] In some preferred embodiments, the feed liquid is discharged from the bottom of the catalytic oxidation tower 14 through an Ω-shaped stabilizing pipe. The front end of the Ω-shaped stabilizing pipe is sealed to the liquid outlet at the bottom of the catalytic oxidation tower 14, and the rear end is connected to the catalytic tower water outlet tank (not shown in the figure). Its core function is to maintain the stability of the liquid level in the catalytic oxidation tower 14, avoid the liquid level fluctuation from affecting the gas-liquid two-phase contact effect, thereby improving the ozone utilization rate and ensuring the stability of the treatment effect.

[0084] After treatment by the deep TOC removal unit, all indicators of the feed solution meet the preset targets: the TOC content of the effluent is less than 80 mg / L, and the oil content is less than 1 mg / L; the oxidation-reduction potential (ORP) of the effluent changes by less than 70 mV compared with the influent, avoiding drastic potential fluctuations that could affect subsequent electrowinning processes; the residual oxidant content is less than 5 mg / L, with no secondary pollution; at the same time, the operating cost of the entire unit is controllable, with a treatment cost of less than 8 yuan per ton of water, balancing treatment effect, industrial adaptability, and economy.

[0085] Example 1

[0086] This embodiment provides a deep degreasing and TOC removal process for molten metal, including the following steps:

[0087] (1) A nickel sulfate metal solution produced by a certain enterprise has a pH of 4.5, a temperature of 60℃, a nickel ion content of 90 g / L, a TOC content of 300 mg / L, and an oil content of 100 mg / L. The solution is fed into the coalescence adsorption column 2 (the packing material is coalescence resin) by a pre-oil removal inlet pump 1 at an inlet flow rate of 2.5 BV / h. Then it enters the oil-water separator 3 and is left to stand for 2 hours. After stratification, the lower layer of effluent is discharged into the coalescence effluent tank 5 for 2 hours to obtain pre-oil removal effluent.

[0088] (2) The pre-oil-removed effluent from the coalescing effluent tank 5 is sent to the deep oil removal unit via the activated carbon addition tank inlet pump 6. The deep oil removal is carried out by two-stage activated carbon addition and alternating plate and frame carbon filtration. The activated carbon used is coconut shell powder activated carbon with a particle size of 200 mesh and an iodine value ≥1000 mg / g. During the first run, the activated carbon addition is 0.8‰ (W / V) of the liquid volume. During the subsequent alternating run, the activated carbon addition is adjusted to 0.4‰ (W / V) of the liquid volume.

[0089] (3) The deep de-oiling effluent obtained in step (2) is sent to the pipeline mixer 13 via the catalytic tower inlet pump 12. At the same time, hydrogen peroxide with a mass concentration of 30% is sent to the pipeline mixer 13 via the liquid oxidant dosing pump 15. The amount of 30% hydrogen peroxide added is 2‰ (V / V) of the liquid volume. After the liquid and hydrogen peroxide are fully mixed in the pipeline mixer 13, they enter the catalytic oxidation tower 14 from the top and form a counter-contact with the ozone sent from the aeration component at the bottom of the catalytic oxidation tower 14. After reacting in the tower for 1.5 hours, the reacted liquid is discharged from the bottom of the catalytic oxidation tower 14 through the Ω-shaped pipe to the catalytic tower outlet tank.

[0090] The concentration of ozone was 140 mg / L, and the mass ratio of ozone dosage to TOC in the influent (i.e., deep oil removal effluent) (O / T) was 14.

[0091] The catalytic oxidation tower 14 is a vertical cylindrical structure with a height-to-diameter ratio of 7:1. The central section contains a catalyst loading zone, which is filled with a packing body composed of multiple corrugated plates stacked together. The thickness of this packing body is half the effective liquid height. The inclination angle of the corrugated plates is 30°~45°, and the corrugated plates are evenly distributed with diamond-shaped openings. The longitudinal dimension of each diamond-shaped opening is 20mm, and the short dimension is 15mm. The edges of the diamond-shaped openings are folded upwards to a height of 5mm, and the diamond-shaped openings on adjacent corrugated plates are staggered. The surface of the packing body is loaded with a Ni-Ce composite oxide (NiO-CeO2, Ni:Ce molar ratio = 4:1, loading amount 10 g / m³). 2 ).

[0092] The test results of the liquid material at each stage are shown in Table 1 below.

[0093] Table 1

[0094]

[0095] The ORP difference between the effluent from the deep TOC removal and the effluent from the deep oil removal was measured to be 41 mV.

[0096] Example 2

[0097] This embodiment provides a deep degreasing and TOC removal process for molten metal, which differs from Embodiment 1 in that:

[0098] (1) A company produces nickel sulfate metal solution with pH=4.5, temperature 25℃, nickel content 90 g / L, TOC content 300mg / L, oil content 100 mg / L, inlet flow rate 5 BV / h, and oil-water separator residence time 1 h.

[0099] (2) The activated carbon used is coconut shell granular activated carbon with a particle size of 20 mesh and an iodine value of ≥1000 mg / g. During the first run, the activated carbon dosage is 1.2‰ (W / V) of the liquid volume. During subsequent alternating runs, the activated carbon dosage is adjusted to 0.8‰ (W / V) of the liquid volume.

[0100] (3) 30% hydrogen peroxide dosage 1‰ (V / V), ozone catalytic oxidation tower residence time 1.5 h, ozone concentration 140mg / L, O / T=10, catalytic oxidation tower height-to-diameter ratio 4:1.

[0101] The test results of the liquid material at each stage are shown in Table 2 below.

[0102] Table 2

[0103]

[0104] The ORP difference between the effluent from the deep TOC removal and the effluent from the deep oil removal was measured to be 34 mV.

[0105] Example 3

[0106] This embodiment provides a deep degreasing and TOC removal process for molten metal, which differs from Embodiment 1 in that:

[0107] (1) A certain enterprise produces nickel sulfate metal solution with pH=4.5, temperature 70℃, nickel content 90 g / L, TOC content 300mg / L, oil content 100 mg / L, inlet flow rate 7.5 BV / h, and oil-water separator residence time 4 h;

[0108] (2) The activated carbon used is anthracite powder activated carbon with a particle size of 300 mesh and an iodine value of ≥1000 mg / g. During the first run, the activated carbon dosage is 0.5‰ (W / V) of the liquid volume. During subsequent alternating runs, the activated carbon dosage is adjusted to 0.2‰ (W / V) of the liquid volume.

[0109] (3) The liquid oxidant is a 10 mmol sodium persulfate aqueous solution, the dosage is 0.25‰ (V / V), the residence time of the ozone catalytic oxidation tower is 2 h, the ozone concentration is 170 mg / L, O / T=8, and the height-to-diameter ratio is 5:1.

[0110] The test results of the liquid material at each stage are shown in Table 3 below.

[0111] Table 3

[0112]

[0113] The ORP difference between the effluent from deep TOC removal and deep oil removal was measured to be 12 mV.

[0114] Example 4

[0115] This embodiment provides a deep degreasing and TOC removal process for molten metal, which differs from Embodiment 1 in that:

[0116] (1) A certain enterprise produces cobalt chloride metal liquid with pH=2.62, temperature 30℃, cobalt content 90 g / L, inlet flow rate 5BV / h, and oil-water separator residence time 2h;

[0117] (2) The activated carbon used is coconut shell powder activated carbon with a particle size of 300 mesh and an iodine value of ≥1000 mg / g. During the first run, the activated carbon dosage is 1.2‰ (W / V) of the liquid volume. During subsequent alternating runs, the activated carbon dosage is adjusted to 0.8‰ (W / V) of the liquid volume.

[0118] (3) The residence time of the ozone catalytic oxidation tower is 3 h, the ozone concentration is 120 mg / L, the O / T=13, and the height-to-diameter ratio of the catalytic oxidation tower is 5:1.

[0119] The test results of the liquid material at each stage are shown in Table 4 below.

[0120] Table 4

[0121]

[0122] The ORP difference between the effluent from deep TOC removal and deep oil removal was measured to be 19 mV.

[0123] Comparative Example 1

[0124] This comparative example provides a deep degreasing and TOC removal process for metal slurry. The only difference between this process and Example 1 is that in step (2), activated carbon is directly added and filtered after stirring, without a circulating alternating carbon filtration process, and the single addition amount is 1‰ (W / V).

[0125] The test results of the liquid material at each stage are shown in Table 5 below.

[0126] Table 5

[0127]

[0128] The ORP difference between the effluent from the deep TOC removal and the effluent from the deep oil removal was measured to be 85 mV.

[0129] Comparative Example 2

[0130] This comparative example provides a deep degreasing and TOC removal process for molten metal feed. The difference between this process and Example 1 is that in step (3), the catalytic oxidation tower 14 is filled with packing material, and the packing material is loaded with 20 g / m³ of packing material. 2 Carbon-based catalysts.

[0131] The test results of the liquid material at each stage are shown in Table 6 below.

[0132] Table 6

[0133]

[0134] The ORP difference between the effluent from deep TOC removal and deep oil removal was measured to be 80 mV.

[0135] Comparative Example 3

[0136] This comparative example provides a deep degreasing and TOC removal process for metal feed liquid. The difference between this process and Example 1 is that in step (3), the catalytic oxidation tower 14 is filled with a nickel-cerium oxide catalyst (NiO-CeO2, Ni:Ce molar ratio = 4:1, dosage 20g / m³). 2 ), irregular packing.

[0137] The test results of the liquid material at each stage are shown in Table 7 below.

[0138] Table 7

[0139]

[0140] The ORP difference between the effluent from deep TOC removal and deep oil removal was measured to be 77 mV.

[0141] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A deep degreasing and TOC removal system for molten metal, characterized in that, It includes a pre-degreasing unit, a deep degreasing unit, and a deep TOC removal unit that are connected in sequence. The pre-oil removal unit includes a pre-oil removal inlet pump (1), a coalescing adsorption column (2), an oil-water separator (3), and a coalescing outlet tank (5) connected in sequence. The deep oil removal unit includes an activated carbon addition tank inlet pump (6), activated carbon addition tank I (7), plate and frame carbon filter I (8), activated carbon addition tank II (9), and plate and frame carbon filter II (10) connected in sequence. The inlet of the activated carbon addition tank inlet pump (6) is connected to the outlet of the coalescing water outlet tank (5), the outlet of the activated carbon addition tank inlet pump (6) is connected to the inlet of the activated carbon addition tank II (9), and the outlet of the plate and frame carbon filter II (10) is connected to the inlet of the activated carbon addition tank I (7), forming a two-stage activated carbon addition and alternating plate and frame carbon filtration circulation structure. The deep TOC removal unit includes a catalytic tower inlet tank (11), a catalytic tower inlet pump (12), a pipeline mixer (13), and a catalytic oxidation tower (14) connected in sequence. The pipeline mixer (13) is connected in sequence to a liquid oxidant dosing pump (15) and a liquid oxidant storage tank (16). The bottom of the catalytic oxidation tower (14) is equipped with an aeration component, which is connected to an ozone generating unit. The inlet of the catalytic tower inlet tank (11) is connected to the outlet of plate and frame carbon filter I (8) and plate and frame carbon filter II (10), respectively.

2. The deep degreasing and TOC removal system for molten metal as described in claim 1, characterized in that, The catalyst loading zone is located in the middle section of the catalytic oxidation tower (14). The catalyst loading zone is filled with a packing body composed of multiple corrugated plates stacked together. The surface of the packing body is loaded with a catalyst. The corrugated plates are evenly distributed with diamond-shaped openings. The edges of the diamond-shaped openings are folded upward to form an orifice plate. The diamond-shaped openings on two adjacent corrugated plates are staggered.

3. The deep degreasing and TOC removal system for molten metal as described in claim 2, characterized in that, The inclination angle of the corrugated plate is 30°~45°; The longitudinal dimension of the diamond-shaped opening is 15~20 mm, and the short dimension is 12~15 mm; The height of the perforated plate is 5~8 mm; The thickness of the packing body is 1 / 3 to 2 / 3 of the effective liquid height inside the tower; The catalyst is a Ni-Ce composite oxide, with a molar ratio of Ni to Ce of 4~8:1; The catalyst loading is 1~10 g / m³. 2 .

4. The deep degreasing and TOC removal system for molten metal as described in claim 1, characterized in that, The catalytic oxidation tower (14) is a vertical cylindrical structure with a height-to-diameter ratio of 3:1 to 10:

1. The outer diameter of the tower is less than 3m, and the effective liquid height inside the tower is less than 7m. The tower body is made of 316L stainless steel or higher grade corrosion-resistant stainless steel.

5. The deep degreasing and TOC removal system for molten metal as described in claim 1, characterized in that, The system also includes a catalytic tower outlet tank, and the outlet of the catalytic oxidation tower (14) is connected to the catalytic tower outlet tank by an Ω-shaped pipe.

6. A deep degreasing and TOC removal process for molten metal based on the system according to any one of claims 1-5, characterized in that, The process includes: (1) The metal liquid is fed into the coalescence adsorption column (2) by the pre-oil removal inlet pump (1) for coalescence and oil removal, and then enters the oil-water separator (3) for static stratification. After stratification, the lower layer of water is discharged into the coalescence water outlet tank (5). (2) The effluent from the coalescing effluent tank (5) is sent to the deep oil removal unit by the activated carbon addition tank inlet pump (6). Deep oil removal is carried out by two-stage activated carbon addition and alternating plate and frame carbon filtration to obtain deep oil-removed effluent. (3) The deep oil removal effluent enters the catalytic tower inlet tank (11) and is sent to the pipeline mixer (13) by the catalytic tower inlet pump (12). At the same time, the liquid oxidant is sent to the pipeline mixer (13) by the liquid oxidant dosing pump (15). After mixing, it is sent to the catalytic oxidation tower (14) and undergoes countercurrent catalytic oxidation with the ozone supplied by the ozone generation unit to obtain a feed liquid with an oil content of <1mg / L and a TOC content of 10~80mg / L.

7. The deep degreasing and TOC removal process for molten metal as described in claim 6, characterized in that, In step (1), The metal feed solution is one or a mixture of nickel cobalt manganese sulfate extract and nickel cobalt manganese chloride extract. The metal molten metal has a pH of 2-6, a temperature of 20-80℃, and a metal ion concentration of >40 g / L; The packing material of the coalescing adsorption column (2) is coalescing resin or coalescing fiber, and the influent flow rate is 2~7.5 BV / h; The residence time of the oil-water separator (3) is 1~4h, and the residence time of the coalescing outlet tank (5) is 1~2.5h.

8. The deep degreasing and TOC removal process for molten metal according to claim 6, characterized in that, In step (2), the specific process of adding the two-stage activated carbon and alternating plate and frame carbon filtration is as follows: The water effluent from the coalescing effluent tank (5) is sent into the activated carbon addition tank II (9) via the activated carbon addition tank inlet pump (6). Activated carbon is added into the activated carbon addition tank II (9) and mixed thoroughly. The water is then filtered through the plate and frame carbon filter II (10) to form an activated carbon filter cake. The effluent then enters the deep TOC removal unit. The next batch of coalescing effluent (5) is sent to activated carbon addition tank II (9) via activated carbon addition tank inlet pump (6) without adding activated carbon. It is filtered by plate and frame carbon filter II (10) using the activated carbon filter cake formed in the previous batch. The effluent enters activated carbon addition tank I (7), where activated carbon is added and fully mixed. It is then filtered by plate and frame carbon filter I (8) to form a new activated carbon filter cake. The effluent enters the deep TOC removal unit. At the same time, the old filter cake is removed from plate and frame carbon filter II (10). The effluent from the subsequent batch coalescing effluent tank (5) is sent to the activated carbon addition tank I (7) via the activated carbon addition tank inlet pump (6). No activated carbon is added. The effluent is filtered through the plate and frame carbon filter I (8) using the activated carbon filter cake formed in the previous batch. The effluent enters the activated carbon addition tank II (9), where activated carbon is added and fully mixed. The effluent is then filtered through the plate and frame carbon filter II (10) and a new activated carbon filter cake is formed. The effluent enters the deep TOC removal unit. At the same time, the old filter cake is removed from the plate and frame carbon filter I (8). This cycle repeats.

9. The deep degreasing and TOC removal process for molten metal according to claim 8, characterized in that, The activated carbon is fruit shell carbon or coal-based carbon with a particle size of 2-500 mesh; During the initial operation, the activated carbon dosage is 0.5~4‰ (W / V), and during subsequent alternating operation, the activated carbon dosage is 0.2~2‰ (W / V).

10. The deep degreasing and TOC removal process for molten metal according to claim 6, characterized in that, In step (3), The liquid oxidant includes hydrogen peroxide with a mass concentration of 28-35% and sodium persulfate aqueous solution with a mass concentration of 8-10 mmol / L, and the dosage is 0.2-5‰ (V / V). The conditions for catalytic oxidation are as follows: the feed temperature is 20~80℃, the ozone concentration is 100~200mg / L, the ratio of ozone dosage to TOC mass of influent is 2~15, and the residence time of the feed in the catalytic oxidation tower (14) is 0.5~3 h.

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