Method and system for treating cold rolling sludge

Abstract

The present disclosure relates to a method and system for treating cold-rolled sludge. First, a homogenizer is used to homogenize the cold-rolled sludge raw material to be treated, so that the cold-rolled sludge can be preliminarily reduced and the subsequent separation efficiency can be improved. The present disclosure uses solid-liquid separation to obtain a first recovered oil and a wet slag material from the homogenized mixed material. The wet slag material is subjected to oil phase extraction and then solid-liquid separation to obtain an oil-containing extractant and a second iron slag. The oil-containing extractant is separated by distillation to obtain a circulating extractant material and a second recovered oil. The present disclosure realizes resource utilization of the iron powder and oil phase contained in the cold-rolled sludge, wherein the separated oil phase can be further purified. In addition, the extractant can be recycled, and no additional wastewater is generated during the extraction process, which is beneficial to environmental protection and resource conservation.

Description

Technical Field

[0001] The present disclosure relates to the field of metallurgical environmental protection technology, and in particular to a method and system for treating cold rolling sludge. Background Art

[0002] Cold mill sludge is a byproduct of the steel rolling process. It appears as a black emulsion with a pungent odor and contains animal and vegetable oils, mineral oils, various additives, and solid impurities. It is complex, highly stable, and difficult to degrade naturally. Currently, steel mills typically outsource cold mill sludge disposal as hazardous waste, a treatment method that increases costs and wastes the recyclable resources contained in the sludge.

[0003] For example, Chinese invention patent application No. 201510290069.7 discloses a cold-rolling sludge degreasing agent and its use method. This method involves uniformly mixing the degreasing agent with the cold-rolling sludge, extracting the oil from the sludge with the degreasing agent, and then filtering the mixture to obtain iron powder. This solution recycles the iron powder, but the oil in the sludge is not reutilized, and the sludge treatment process generates a large amount of wastewater.

[0004] For example, Chinese invention patent application number 201910173772.8 discloses a method for cleaning waste rolling oil sludge. This method involves mixing the sludge with a deoiling agent, centrifuging to obtain a solid-liquid phase, separating the liquid phase from the oil and water, and repeatedly washing and centrifuging the solid phase residue. Finally, the solid phase is rinsed and dried to obtain iron powder. This method extracts the iron powder, but the oil phase obtained after the oil-water separation is not further purified, and the effectiveness of the oil-water separation is not demonstrated. Furthermore, this method's sludge treatment process is complex, requiring multiple mixing, stirring, and centrifugation steps.

[0005] In summary, the prior art currently does not provide a method for recovering iron powder and oil phase from cold rolling sludge by resource utilization. Summary of the Invention

[0006] The purpose of the present disclosure is to provide a method and system for treating cold rolling sludge, so as to realize resource utilization of cold rolling sludge, recover iron powder and oil phase, improve higher economic benefits and reduce environmental pressure.

[0007] To achieve the above-mentioned objectives, the present disclosure provides, in a first aspect, a method for treating cold-rolled sludge, comprising the following steps: S1, homogenizing a cold-rolled sludge raw material and a homogenizer in a homogenizing device to obtain a homogenous mixture; introducing the homogenous mixture into a first separation device for a first solid-liquid separation to obtain a first recovered oil and a wet slag material; S2, introducing the first recovered oil into a filtering device for filtration to obtain purified recovered oil and a first iron slag; contacting the wet slag material with an extractant in an extraction device for extraction treatment to obtain an extraction mixture; S3, introducing the extraction mixture into a second separation device for a second solid-liquid separation to obtain an oil-containing extractant and a second iron slag; introducing the oil-containing extractant into a distillation tower for distillation separation to obtain a circulating extractant material and a second recovered oil; and S4, returning the circulating extractant material to the extraction device for continued use.

[0008] Optionally, the method further includes: allowing the second recovered oil obtained from the distillation tower to enter the filtering device, and filtering it together with the first recovered oil from the first separation device to obtain the purified recovered oil; optionally, the method further includes: condensing the circulating extractant material obtained from the distillation tower to a liquid phase and then returning it to the extraction device; preferably, the temperature of the condensed circulating extractant material is 50-80°C; optionally, the method further includes: allowing the first recovered oil from the first separation device to enter a storage tank, and then enter the filtering device for filtration; allowing the second recovered oil from the distillation tower to enter the storage tank, mix with the first recovered oil, and then enter the filtering device.

[0009] Optionally, the method further includes: allowing the first iron slag from the filtering device and the second iron slag from the second separation device to enter a drying device for drying respectively to obtain sintering raw materials; preferably, the drying temperature is 100-500°C; preferably, the oil content of the iron powder after drying is 1-3 weight%.

[0010] Optionally, the homogenizer includes nonylphenol polyoxyethylene ether, polyacrylamide and glycerol polyoxyethylene polyoxypropylene ether; preferably, the weight ratio of nonylphenol polyoxyethylene ether: polyacrylamide: glycerol polyoxyethylene polyoxypropylene ether is 1: (0.02-0.1): (0.2-0.4); preferably 1: (0.02-0.1): (0.3-0.4); preferably, the weight average molecular weight of the nonylphenol polyoxyethylene ether is 400-1600, and the weight average molecular weight of the polyacrylamide is 5×10 6 ~2×10 7, the weight average molecular weight of the glycerol polyoxyethylene polyoxypropylene ether is 500-2000; preferably, based on the total weight of the cold-rolled sludge raw material, the added amount of the homogenizer is 200-1000 mg / kg, preferably 300-500 mg / kg; preferably, the mixing conditions in the homogenizing device include: temperature of 30-80°C, time of 10-30 min; preferably, under mechanical stirring conditions, the stirring rate is 50-200 r / min.

[0011] Optionally, the filtering device is provided with a filter element composed of a filtering material, the pore size of the filtering material is 0.5 to 1 μm; the material of the filtering material is polytetrafluoroethylene; preferably, the conditions for filtering in the filtering device include: the filter element temperature is 50 to 95°C; preferably, the mechanical impurity content in the recovered oil obtained after the filtration is 0.001 to 0.02 weight%.

[0012] Optionally, the conditions of the extraction treatment include: the weight ratio of the extractant to the wet residue material is (1:1) to (10:1); preferably (3:1) to (5:1), the temperature is 30 to 100°C, preferably 50 to 80°C, and the time is 10 to 120 min, preferably 30 to 60 min; preferably, the extraction is carried out under mechanical stirring at a stirring rate of 300 to 600 r / min; preferably, the extractant is selected from one or more of aromatic-rich distillate oil, solvent oil, kerosene, ether, ethyl acetate and petroleum ether.

[0013] Optionally, the distillation separation conditions of the distillation tower include: the temperature of the liquid phase material in the tower is 100-350° C., and the time is 30-120 min; preferably, the temperature is 200-300° C., and the time is 60-90 min.

[0014] Optionally, based on the total weight of the cold-rolled sludge raw material, the cold-rolled sludge raw material includes 10-15 weight% water, 10-20 weight% iron slag solid, and 70-80 weight% oil, wherein the oil includes waste lubricating oil; and the particle size of the iron slag solid is 11-365 μm.

[0015] The second aspect of the present disclosure provides a system for treating cold-rolled sludge, the system comprising a homogenizing device, a first separating device, a filtering device, an extracting device, a second separating device and a distillation tower; the homogenizing device is provided with a cold-rolled sludge inlet, a homogenizer inlet and a homogenized mixture outlet; the first separating device is provided with a first separating inlet, a first liquid phase outlet and a wet slag material outlet, the first separating inlet is connected to the homogenized mixture outlet of the homogenizing device; the filtering device is provided with a filtering inlet, a recovered oil outlet and a first iron slag outlet, and a filtering material is provided inside; the filtering inlet is connected to the first liquid phase outlet of the first separating device, and the recovered oil outlet is used to be connected to the recovered oil outlet. The oil storage device is connected; the extraction device is provided with a wet slag material inlet, an extractant inlet and an extraction mixture outlet, and the wet slag material inlet is connected to the wet slag material outlet of the first separation device; the second separation device is provided with a second separation inlet, a second liquid phase outlet and a second iron slag outlet, and the second separation inlet is connected to the extraction mixture outlet of the extraction device; the distillation tower is provided with a distillation material inlet, a light component outlet and a heavy component outlet, and the distillation material inlet is connected to the second liquid phase outlet of the second separation device, and the light component outlet is connected to the extractant inlet of the extraction device; the heavy component outlet is connected to the filtration inlet of the filtration device.

[0016] Optionally, the system further comprises: a drying device and a condenser; the inlet of the drying device is respectively connected to the first iron slag outlet of the filtering device and the second iron slag outlet of the second separation device, and the outlet of the drying device is used to be connected to a subsequent sintering device; the inlet of the condenser is connected to the light component outlet of the distillation tower, and the liquid phase material outlet of the condenser is connected to the extractant inlet of the extraction device; optionally, the system further comprises: a homogenizer storage device, a recovered oil storage device, a wet slag storage device, an extractant storage device, an iron slag storage device, and a circulating oil storage device; the homogenizer storage device is connected to the homogenizer inlet of the homogenizer for introducing the homogenizer into the homogenizer; the inlet of the recovered oil storage device is respectively connected to the first liquid phase outlet of the first separation device and the heavy component outlet of the distillation tower, and the outlet of the recovered oil storage device is connected to the filter inlet of the filtering device the inlet of the wet slag storage device is connected with the wet slag material outlet of the first separation device, and the outlet of the wet slag storage device is connected with the wet slag material inlet of the extraction device; the extractant storage device is provided with an extractant circulation inlet and an extractant circulation outlet, the extractant circulation outlet is connected with the extractant inlet of the extraction device, and the extractant circulation inlet is connected with the liquid phase material outlet of the condensing device; the inlet of the iron slag storage device is connected with the second iron slag outlet of the second separation device, and the outlet of the iron slag storage device is connected with the inlet of the drying device; the inlet of the circulating oil storage device is connected with the second liquid phase outlet of the second separation device, and the outlet of the circulating oil storage device is connected with the distillation material inlet of the distillation tower; optionally, the first separation device and the second separation device are both centrifuges; and a mechanical stirring device is provided in both the homogenizing device and the extraction device.

[0017] Through the above technical scheme, the present disclosure provides a method and system for treating cold-rolled sludge, which first uses a homogenizer to homogenize the cold-rolled sludge raw material to be treated, and can perform preliminary reduction treatment on the cold-rolled sludge, thereby improving the subsequent separation efficiency; the present disclosure can obtain a first recovered oil and a wet slag material by solid-liquid separation of the homogenized mixed material, extract the oil phase of the wet slag material, and then perform solid-liquid separation to obtain an oil-containing extractant and a second iron slag, wherein the oil-containing extractant is separated by distillation to obtain a circulating extractant material and a second recovered oil, and the present disclosure realizes the resource utilization of the iron powder and oil phase contained in the cold-rolled sludge, wherein the separated oil phase can be further purified; and the extractant can be recycled, and no additional wastewater is generated during the extraction process, which is beneficial to environmental protection and resource conservation.

[0018] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following detailed description, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0020] Figure 1 This is a process flow chart for treating cold rolling sludge provided by the present invention.

[0021] Description of Reference Numerals

[0022] 1-Homogenizer storage device, 2-Homogenizer, 3-First separation device, 4-Recovered oil storage device, 5-Filter, 6-Wet slag storage device, 7-Extractant storage device, 8-Extraction device, 9-Second separation device, 10-Iron slag storage device, 11-Drying device, 12-Circulating oil storage device, 13-Distillation tower, 14-Condenser DETAILED DESCRIPTION

[0023] The following describes the specific embodiments of the present disclosure in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure and are not intended to limit the present disclosure.

[0024] In this disclosure, unless otherwise indicated, terms such as "first," "second," and "third" are used solely to distinguish between components and do not imply a specific order of connection. In this disclosure, directional terms such as "upper," "lower," "top," and "bottom" generally refer to the top and bottom, or top and bottom, of a device in normal use. "Inside" and "outside" refer to the outline of a device.

[0025] The first aspect of the present disclosure provides a method for treating cold rolling sludge, such as Figure 1 As shown, the following steps are included:

[0026] S1, homogenizing the cold-rolled oil sludge raw material and the homogenizer in a homogenizing device 2 to obtain a homogeneous mixture; introducing the homogenous mixture into a first separation device 3 for a first solid-liquid separation to obtain a first recovered oil and a wet residue material;

[0027] S2, introducing the first recovered oil into the filtering device 5 for filtration to obtain purified recovered oil and first iron slag;

[0028] The wet residue material is brought into contact with an extractant in an extraction device 8 for extraction treatment to obtain an extraction mixture;

[0029] S3, introducing the extraction mixture into a second separation device 9 for a second solid-liquid separation to obtain an oil-containing extractant and a second iron slag;

[0030] The oil-containing extractant is introduced into a distillation column 13 for distillation separation to obtain a circulating extractant material and a second recovered oil;

[0031] S4, returning the circulating extractant material to the extraction device 8 for continued use.

[0032] The present disclosure provides a method for treating cold-rolled sludge. First, a homogenizer is used to homogenize the cold-rolled sludge raw material to be treated, so that the cold-rolled sludge can be preliminarily reduced and the subsequent separation efficiency can be improved. The present disclosure performs solid-liquid separation on the homogenized mixed material to obtain a first recovered oil and a wet slag material. The wet slag material is subjected to oil phase extraction and then solid-liquid separation to obtain an oil-containing extractant and a second iron slag, wherein the oil-containing extractant is separated by distillation to obtain a circulating extractant material and a second recovered oil. The present disclosure realizes resource utilization of the iron powder and oil phase contained in the cold-rolled sludge, wherein the separated oil phase can be further purified. Moreover, the extractant can be recycled, and no additional wastewater is generated during the extraction process, which is beneficial to environmental protection and resource conservation.

[0033] In a specific embodiment, based on the total weight of the cold-rolled sludge raw material, the cold-rolled sludge raw material includes 10-15 weight% water, 10-20 weight% iron slag solid, and 70-80 weight% oil, wherein the oil includes waste lubricating oil; the particle size of the iron slag solid is 11-365 μm.

[0034] The inventors of the present disclosure found in research experiments that compared with the traditional use of degreasing agents or deoiling agents to extract oil from cold-rolled sludge, using a homogenizer to first homogenize the cold-rolled sludge is beneficial to the initial reduction of the sludge and improve the subsequent solid-liquid separation effect of the homogeneous mixture.

[0035] In a preferred embodiment, the homogenizer includes nonylphenol polyoxyethylene ether, polyacrylamide, and glycerol polyoxyethylene polyoxypropylene ether; preferably, the weight ratio of nonylphenol polyoxyethylene ether: polyacrylamide: glycerol polyoxyethylene polyoxypropylene ether is 1: (0.02-0.1): (0.2-0.4), preferably 1: (0.02-0.1): (0.3-0.4). In actual use, the homogenizer can be prepared as a deionized water solution with a mass fraction of the homogenizer of 2% by weight.

[0036] In a preferred embodiment, the weight average molecular weight of the nonylphenol polyoxyethylene ether is preferably 400 to 1600, and the weight average molecular weight of the polyacrylamide is 5×10 6 ~2×10 7 The weight average molecular weight of the glycerol polyoxyethylene polyoxypropylene ether is 500 to 2000.

[0037] Preferably, based on the total weight of the cold-rolled sludge raw material, the amount of the homogenizer added is 200-1000 mg / kg, preferably 300-500 mg / kg.

[0038] In a preferred embodiment, the mixing conditions in the homogenizing device 2 include: a temperature of 30 to 80° C., a time of 10 to 30 min; preferably, under mechanical stirring conditions, a stirring rate of 50 to 200 r / min.

[0039] In one embodiment, the filter device 5 is provided with a filter element composed of a filter material, the pore size of the filter material is 0.5 to 1 μm; the material of the filter material is polytetrafluoroethylene.

[0040] In a specific embodiment, the contact angle of the filter material with the water phase is 121°, and the contact angle with the oil phase is 0°.

[0041] In a specific embodiment, the conditions for filtering in the filtering device 5 include: the filter element temperature is 50 to 95°C;

[0042] Preferably, the mechanical impurity content in the recovered oil obtained after the filtration is 0.001 to 0.02% by weight. The present disclosure can further purify the recovered oil through the filtration device.

[0043] The filter element in the filter device disclosed herein is arranged in a manner conventionally selected in the art.

[0044] As is known in the disclosure, mechanical impurities refer to precipitates or colloidal suspensions in lubricating oil that are insoluble in solvents such as gasoline, ethanol, and benzene. These impurities are mostly sand and gravel, iron filings, and some organic metal salts that are difficult to dissolve in solvents and are introduced by additives.

[0045] In one embodiment, the extraction treatment conditions include: the weight ratio of the extractant to the wet slag material is (1:1) to (10:1); preferably (3:1) to (5:1); the temperature is 30 to 100° C., preferably 50 to 80° C., and the time is 10 to 120 minutes, preferably 30 to 60 minutes; preferably, the extraction is carried out under mechanical stirring at a stirring rate of 300 to 600 r / min;

[0046] Preferably, the extractant is selected from one or more of aromatics-rich distillate oil, solvent oil, kerosene, ether, ethyl acetate and petroleum ether.

[0047] In one embodiment, the temperature of the liquid phase material in the tower is 100-350° C., and the time is 30-120 min; preferably, the temperature is 200-300° C., and the time is 60-90 min.

[0048] In a preferred embodiment, Figure 1 As shown, the method further includes:

[0049] The second recovered oil obtained from the distillation tower 13 enters the filtering device 5 and is filtered together with the first recovered oil from the first separation device 3 to obtain the purified recovered oil;

[0050] Optionally, the method further comprises: the circulating extractant material obtained by the distillation tower 13

[0051] After condensing to a liquid phase, it returns to the extraction device 8; preferably, the temperature of the circulating extractant material after condensation is 50-80°C;

[0052] Optionally, the method further includes: allowing the first recovered oil from the first separation device 3 to enter the storage tank 4 and then enter the filtering device 5 for filtration; allowing the second recovered oil from the distillation tower 13 to enter the storage tank 4 and then enter the filtering device 5 after mixing with the first recovered oil.

[0053] In a preferred embodiment, the method further comprises:

[0054] The first iron slag from the filtering device 5 and the second iron slag from the second separating device 9 are respectively dried in the drying device 11 to obtain sintering raw materials; preferably, the drying temperature is 100-500°C; preferably, the oil content of the iron powder after drying is 1-3% by weight.

[0055] The second aspect of the present disclosure provides a system for treating cold rolling sludge, such as Figure 1 As shown, the system includes a homogenizing device 2, a first separating device 3, a filtering device 5, an extraction device 8, a second separating device 9 and a distillation tower 13; the homogenizing device 2 is provided with a cold rolling sludge inlet, a homogenizer inlet and a homogenized mixture outlet; the first separating device 3 is provided with a first separating inlet, a first liquid phase outlet and a wet slag material outlet, and the first separating inlet is connected to the homogenized mixture outlet of the homogenizing device 2; the filtering device 5 is provided with a filtering inlet, a recovered oil outlet and a first iron slag outlet, and a filtering material is provided inside; the filtering inlet is connected to the first liquid phase outlet of the first separating device 3, and the recovered oil outlet is used to store the recovered oil. The devices are connected; the extraction device 8 is provided with a wet slag material inlet, an extractant inlet and an extraction mixture outlet, and the wet slag material inlet is connected to the wet slag material outlet of the first separation device 3; the second separation device 9 is provided with a second separation inlet, a second liquid phase outlet and a second iron slag outlet, and the second separation inlet is connected to the extraction mixture outlet of the extraction device 8; the distillation tower 13 is provided with a distillation material inlet, a light component outlet and a heavy component outlet, the distillation material inlet is connected to the second liquid phase outlet of the second separation device 9, and the light component outlet is connected to the extractant inlet of the extraction device 8; the heavy component outlet is connected to the filtration inlet of the filtration device 5.

[0056] In one embodiment, the system further includes: a drying device 11 and a condenser 14; the inlet of the drying device 11 is connected to the first iron slag outlet of the filtering device 5 and the second iron slag outlet of the second separation device 9, respectively, and the outlet of the drying device 11 is used to communicate with a subsequent sintering device;

[0057] The inlet of the condenser 14 is connected to the light component outlet of the distillation column 13, and the liquid phase material outlet of the condenser 14 is connected to the extractant inlet of the extraction device 8;

[0058] Optionally, the system further comprises: a homogenizer storage device 1, a recovered oil storage device 4, a wet slag storage device 6, an extractant storage device 7, an iron slag storage device 10, and a circulating oil storage device 12; the homogenizer storage device 1 is connected to the homogenizer inlet of the homogenizer 2 for introducing the homogenizer into the homogenizer 2; the inlet of the recovered oil storage device 4 is connected to the first liquid phase outlet of the first separation device 3 and the heavy component outlet of the distillation tower 13 respectively, and the outlet of the recovered oil storage device 4 is connected to the filtering inlet of the filtering device 5; the inlet of the wet slag storage device 6 is connected to the wet slag material outlet of the first separation device 3, and the wet slag storage device 7 is connected to the wet slag material outlet of the first separation device 3. 6 is connected to the wet slag material inlet of the extraction device 8; the extractant storage device 7 is provided with an extractant circulation inlet and an extractant circulation outlet, the extractant circulation outlet is connected to the extractant inlet of the extraction device 8, and the extractant circulation inlet is connected to the liquid phase material outlet of the condensing device 14; the inlet of the iron slag storage device 10 is connected to the second iron slag outlet of the second separation device 9, and the outlet of the iron slag storage device 10 is connected to the inlet of the drying device 11; the inlet of the circulating oil storage device 12 is connected to the second liquid phase outlet of the second separation device 9, and the outlet of the circulating oil storage device 12 is connected to the distillation material inlet of the distillation tower 13.

[0059] In one embodiment, the first separation device 3 and the second separation device 9 are both centrifuges;

[0060] Both the homogenizing device 2 and the extraction device 8 are provided with mechanical stirring devices.

[0061] The devices used in this disclosure are all conventionally selected devices in the art.

[0062] The scheme and effects of the present disclosure are described below through examples.

[0063] The reagents used in the following examples and comparative examples can all be obtained through conventional purchase.

[0064] The filter material is made of polytetrafluoroethylene, has a pore size of 0.5 μm, a contact angle of 121° with the water phase, and a contact angle of 0° with the oil phase. It can be purchased through conventional channels.

[0065] Nonylphenol polyoxyethylene ether was purchased from Sinopharm Group with a weight-average molecular weight of 880;

[0066] Polyacrylamide was purchased from Beijing Hengju, with a weight average molecular weight of 8×10 6 ;

[0067] Glycerol polyoxyethylene polyoxypropylene ether was purchased from Lushun Chemical Plant, and the weight average molecular weight was 1050. In the present disclosure, the weight average molecular weight was obtained by static light scattering and mass spectrometry.

[0068] Example 1

[0069] Take the sludge of a cold rolling emulsion station in a steel plant as an example. The sludge contains 15% water (mass fraction), 10% solids, and more than 70% oil. It has a black and viscous appearance and good fluidity at room temperature. Figure 1 The process shown.

[0070] The homogenizer RP-03 used in this example comprises: nonylphenol polyoxyethylene ether, polyacrylamide, and propylene glycol polyoxyethylene ether. The homogenizer RP-03 is prepared by mixing a 2 wt% deionized water solution containing 1 (nonylphenol polyoxyethylene ether): 0.05 (polyacrylamide): 0.2 (propylene glycol polyoxyethylene ether) in a mass ratio.

[0071] The cold-rolled sludge and the homogenizer RP-03 are added to the homogenizer (homogenizer 2). Based on the weight of the cold-rolled sludge, the amount of RP-03 added is 200 mg / kg. The homogenization is carried out at room temperature for 10 minutes at a stirring speed of 100 r / min. After the homogenization is completed, it is pumped into the horizontal screw centrifuge (first separation device 3) for the first solid-liquid separation, and the centrifugal speed is 3000 rpm. The first recovered oil obtained by centrifugation enters the filter device 5 for further filtration. The filter material is made of polytetrafluoroethylene with a pore size of 0.5 μm, a contact angle with the water phase of 121°, a contact angle with the oil phase of 0°, and a filter element temperature of 80°C. The oil phase obtained after filtration (purified recovered oil) has a mechanical impurity content of 0.005% by weight.

[0072] The wet residue obtained by centrifugation enters the extraction stirrer (extraction device 8), and an extractant is added at the same time. The extractant is a distillate oil rich in aromatics (mass fraction of aromatics 60% by weight). The weight ratio of the extractant to the wet residue material is 2:1, the extraction time is 30 minutes, the extraction temperature is 80°C, and the stirring speed is 400r / min. After the extraction is completed, a horizontal screw centrifuge (second separation device 9) is used for a second solid-liquid separation. The iron slag obtained by centrifugation is further dried in a dryer at a drying temperature of 280°C. The iron powder obtained after drying has an oil content of 3% by weight.

[0073] The oil-containing extractant obtained by centrifugation in the second separation unit 9 is introduced into a distillation tower 13 for distillation at a liquid temperature of 300°C for 60 minutes. The resulting vapor phase (circulating extractant material) is condensed to a liquid phase (60°C) in a condenser 14 and then introduced into the extraction unit 8 for recycling. The heavy component obtained by distillation, as the second recovered oil, is introduced into the filtration unit 5 for filtration to obtain purified recovered oil.

[0074] The recovered oil from the first separation device and the distillation tower was filtered and purified, and the recovery rate of the purified recovered oil compared to the oil content of the cold-rolled sludge was 68% by weight.

[0075] Comparative Example 1

[0076] The process of Example 1 was adopted, except that the homogenizer RP-03 was replaced with sodium lauryl sulfate (a deionized water solution with a mass fraction of 2%). The rest of the process was the same as that of Example 1.

[0077] The oil phase obtained after filtration (purified recovered oil) contained 0.007% by weight of mechanical impurities, and the recovery rate of the purified recovered oil compared to the oil content of the cold-rolled sludge was 53% by weight. The iron powder obtained after the second solid-liquid separation and drying had an oil content of 5% by weight.

[0078] Comparative Example 2

[0079] The process in Example 1 was adopted, except that the homogenizer RP-03 was replaced with the deoiling agent in Example 1 of patent CN109675340A. The rest of the process was the same as in Example 1.

[0080] The mechanical impurity content of the oil phase obtained after filtration (recovered oil after purification) is 0.01 weight%; the recovery rate of the recovered oil after purification is 45 weight% compared with the oil content of the cold-rolled sludge; the oil content of the iron powder obtained after the second solid-liquid separation and drying is 8 weight%.

[0081] Example 2

[0082] The process in Example 1 was adopted, except that the homogenizer RP-03 was replaced with a homogenizer having the following composition: nonylphenol polyoxyethylene ether: polyacrylamide: glycerol polyoxyethylene polyoxypropylene ether in a weight ratio of 1:0.05:0.4, prepared into a deionized water aqueous solution with a mass fraction of 2% by weight.

[0083] The mechanical impurity content of the oil phase obtained after filtration (recovered oil after purification) is 0.005 weight%; the recovery rate of the recovered oil after purification compared with the oil content of the cold-rolled sludge is 70 weight%; the oil content of the iron powder obtained after the second solid-liquid separation and drying is 2.7 weight%.

[0084] Example 3

[0085] The process in Example 1 was adopted, except that the addition amount of the homogenizer RP-03 was changed to 500 mg / kg.

[0086] The mechanical impurity content of the oil phase obtained after filtration (recovered oil after purification) is 0.005 weight%; the recovery rate of the recovered oil after purification is 72 weight% compared with the oil content of the cold-rolled sludge; the oil content of the iron powder obtained after the second solid-liquid separation and drying is 2.7 weight%.

[0087] Example 4

[0088] Take the sludge of a cold rolling emulsion station in a steel plant as an example. The sludge contains 15% water (mass fraction), 10% solids, and more than 70% oil. It has a black and viscous appearance and good fluidity at room temperature. Figure 1 The process shown.

[0089] The cold-rolled sludge and homogenizer RP-03 are added to the homogenizer (homogenizer 2). Based on the weight of the cold-rolled sludge, the amount of RP-03 added is 200 mg / kg. The mixture is homogenized and stirred at 50°C for 30 minutes at a stirring speed of 200 r / min. After homogenization, it is pumped into the horizontal screw centrifuge (first separation device 3) for the first solid-liquid separation at a centrifugal speed of 3000 rpm. The first recovered oil obtained by centrifugation enters the filter device 5 for further filtration. The filter material is made of polytetrafluoroethylene with a pore size of 0.5 μm, a contact angle with the water phase of 121°, a contact angle with the oil phase of 0°, and a filter element temperature of 85°C. The oil phase obtained after filtration (recovered oil after purification) has a mechanical impurity content of 0.005% by weight.

[0090] The wet residue material obtained by centrifugation enters the extraction stirrer (extraction device 8), and an extractant is added at the same time. The extractant is a distillate oil rich in aromatics (the mass fraction of aromatics is 75% by weight). The weight ratio of the extractant to the wet residue material is 5:1, the extraction time is 60 minutes, the extraction temperature is 80°C, and the stirring speed is 400r / min. After the extraction is completed, a horizontal screw centrifuge (second separation device 9) is used for the second solid-liquid separation. The iron slag obtained by centrifugation is further dried in a dryer at a drying temperature of 350°C. The oil content of the iron powder obtained after drying is 2% by weight.

[0091] The oil-containing extractant obtained by centrifugation in the second separation unit 9 is introduced into a distillation tower 13 for distillation at 300°C for 60 minutes. The resulting vapor phase (recycled extractant material) is condensed to a liquid phase (60°C) in a condenser 14 and then introduced into the extraction unit 8 for recycling. The heavy component obtained by distillation, as the second recovered oil, is introduced into the filtration unit 5 for filtration to obtain purified recovered oil.

[0092] The recovered oil from the first separation device and the distillation tower was filtered and purified, and the recovery rate of the purified recovered oil compared to the oil content of the cold-rolled sludge was 74% by weight.

[0093] According to the above Example 1 and Comparative Examples 1 to 2 (conventional emulsifiers or existing deoiling agents), after the cold-rolled sludge is treated with the homogenizer provided by the present invention and the method provided by the present invention, the oil recovered after purification has a higher recovery rate than the oil content of the cold-rolled sludge, the mechanical impurity content in the recovered oil after purification is lower, and the oil content in the iron powder is lower.

[0094] Comparing Example 2 with Example 1, it can be seen that the composition of the homogenizer in Example 2 satisfies the weight ratio of nonylphenol polyoxyethylene ether: polyacrylamide: glycerol polyoxyethylene polyoxypropylene ether of 1: (0.02-0.1): (0.3-0.4), and the oil recovery rate of the purified recovered oil in Example 2 is higher than that of the cold-rolled sludge, and the oil content in the iron powder is lower.

[0095] Comparing Example 3 with Example 1, it can be seen that the amount of homogenizer added in Example 3 meets 300-500 mg / kg, the oil recovery rate of the purified recovered oil in Example 3 is higher than that of the cold-rolled sludge, and the oil content in the iron powder is lower.

[0096] The preferred embodiments of the present disclosure are described in detail above with reference to the accompanying drawings. However, the present disclosure is not limited to the specific details of the above embodiments. Within the technical concept of the present disclosure, various simple modifications can be made to the technical solution of the present disclosure, and these simple modifications all fall within the scope of protection of the present disclosure. For example,

[0097] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present disclosure will not further describe various possible combinations.

[0098] In addition, the various embodiments of the present disclosure may be arbitrarily combined, and as long as they do not violate the concept of the present disclosure, they should also be regarded as the contents disclosed by the present disclosure.

Claims

1. A method for treating cold rolling sludge, characterized in that: The following steps are involved: S1. Homogenize the cold-rolled oil sludge raw material and the homogenizer in a homogenizer (2) to obtain a homogenous mixture; introduce the homogenous mixture into a first separation device (3) for a first solid-liquid separation to obtain a first recovered oil and a wet residue material; the homogenizer comprises nonylphenol polyoxyethylene ether, polyacrylamide, and glycerol polyoxyethylene polyoxypropylene ether; the weight ratio of nonylphenol polyoxyethylene ether: polyacrylamide: glycerol polyoxyethylene polyoxypropylene ether is 1: (0.02-0.1): (0.3-0.4); S2, introducing the first recovered oil into a filtering device (5) for filtration to obtain purified recovered oil and first iron slag; The wet residue material is contacted with an extractant in an extraction device (8) for extraction treatment to obtain an extraction mixture; S3, introducing the extraction mixture into a second separation device (9) for a second solid-liquid separation to obtain an oil-containing extractant and a second iron slag; The oil-containing extractant is introduced into a distillation tower (13) for distillation separation to obtain a circulating extractant material and a second recovered oil; S4, returning the circulating extractant material to the extraction device (8) for continued use.

2. The method according to claim 1, characterized in that The method further includes: The second recovered oil obtained from the distillation tower (13) enters the filtering device (5) and is filtered together with the first recovered oil from the first separation device (3) to obtain the purified recovered oil.

3. The method according to claim 1, characterized in that The method further includes: The circulating extractant material obtained from the distillation tower (13) is condensed into a liquid phase and then returned to the extraction device (8).

4. The method according to claim 3, characterized in that The temperature of the circulating extractant material after condensation is 50~80℃.

5. The method according to claim 2, characterized in that The method further comprises: allowing the first recovered oil from the first separation device (3) to enter the recovered oil storage device (4) and then enter the filtering device (5) for filtration; and allowing the second recovered oil from the distillation tower (13) to enter the recovered oil storage device (4) and enter the filtering device (5) after being mixed with the first recovered oil.

6. The method according to claim 1, wherein The method further includes: The first iron slag from the filtering device (5) and the second iron slag from the second separating device (9) are respectively fed into a drying device (11) for drying to obtain a sintering raw material.

7. The method according to claim 6, characterized in that The drying temperature of the drying device (11) is 100-500°C.

8. The method according to claim 6, characterized in that The oil content of the iron powder after drying is 1 to 3% by weight.

9. The method according to claim 1, characterized in that The weight average molecular weight of the nonylphenol polyoxyethylene ether is 400-1600, and the weight average molecular weight of the polyacrylamide is 5×10 6 ~2×10 7 The weight average molecular weight of the glycerol polyoxyethylene polyoxypropylene ether is 500~2000.

10. The method according to claim 1, characterized in that Based on the total weight of the cold-rolled sludge raw material, the amount of the homogenizer added is 200-1000 mg / kg.

11. The method according to claim 10, characterized in that Based on the total weight of the cold-rolled sludge raw material, the amount of the homogenizer added is 300-500 mg / kg.

12. The method according to claim 1, characterized in that The mixing conditions in the homogenizing device (2) include: a temperature of 30-80°C and a time of 10-30 minutes.

13. The method according to claim 12, characterized in that The mixing in the homogenizing device (2) is carried out under mechanical stirring conditions at a stirring rate of 50-200 r / min.

14. The method according to claim 1, wherein The filtering device (5) is provided with a filter element composed of a filtering material, the pore size of the filtering material is 0.5-1 μm; the material of the filtering material is polytetrafluoroethylene.

15. The method according to claim 14, characterized in that The conditions for filtering in the filtering device (5) include: the filter element temperature is 50-95°C.

16. The method according to claim 14, characterized in that The mechanical impurity content in the recovered oil obtained after the filtration is 0.001-0.02 wt %.

17. The method according to claim 1, wherein The extraction treatment conditions include: a weight ratio of the extractant to the wet slag material of (1:1) to (10:1), a temperature of 30 to 100° C., and a time of 10 to 120 minutes.

18. The method according to claim 17, characterized in that The extraction treatment conditions include: a weight ratio of the extractant to the wet slag material of (3:1) to (5:1), a temperature of 50 to 80° C., and a time of 30 to 60 minutes.

19. The method according to claim 1, wherein The extraction process is carried out under mechanical stirring at a stirring rate of 300-600 r / min.

20. The method according to claim 1, wherein The extractant is selected from one or more of aromatic hydrocarbon-rich distillate oil, solvent oil, kerosene, ether, ethyl acetate and petroleum ether.

21. The method according to claim 1, wherein The distillation separation conditions of the distillation tower (13) include: the temperature of the liquid phase material in the tower is 100~350℃, and the time is 30~120min.

22. The method according to claim 21, characterized in that The distillation separation conditions of the distillation tower (13) include: the temperature of the liquid phase material in the tower is 200-300°C, and the time is 60-90 minutes.

23. The method according to claim 1, wherein Based on the total weight of the cold-rolled sludge raw material, the cold-rolled sludge raw material includes 10-15 weight percent water, 10-20 weight percent iron slag solid, and 70-80 weight percent oil, wherein the oil includes waste lubricating oil; and the particle size of the iron slag solid is 11-365 μm.

24. A system for the method for treating cold rolling sludge according to claim 1, characterized in that: The system comprises a homogenizing device (2), a first separating device (3), a filtering device (5), an extracting device (8), a second separating device (9) and a distillation tower (13); the homogenizing device (2) is provided with a cold rolling sludge inlet, a homogenizer inlet and a homogenizing mixture outlet; the first separating device (3) is provided with a first separating inlet, a first liquid phase outlet and a wet slag material outlet, and the first separating inlet is connected to the homogenizing mixture outlet of the homogenizing device (2); the filtering device (5) is provided with a filtering inlet, a recovered oil outlet and a first iron slag outlet, and a filtering material is provided inside; the filtering inlet is connected to the first liquid phase outlet of the first separating device (3), and the recovered oil outlet is used to connect to a recovered oil storage device The extraction device (8) is provided with a wet slag material inlet, an extractant inlet and an extraction mixture outlet, and the wet slag material inlet is connected to the wet slag material outlet of the first separation device (3); the second separation device (9) is provided with a second separation inlet, a second liquid phase outlet and a second iron slag outlet, and the second separation inlet is connected to the extraction mixture outlet of the extraction device (8); the distillation tower (13) is provided with a distillation material inlet, a light component outlet and a heavy component outlet, the distillation material inlet is connected to the second liquid phase outlet of the second separation device (9), the light component outlet is connected to the extractant inlet of the extraction device (8); the heavy component outlet is connected to the filtration inlet of the filtration device (5).

25. The system according to claim 24, wherein: The system further comprises: a drying device (11) and a condenser (14); the inlet of the drying device (11) is respectively connected to the first iron slag outlet of the filtering device (5) and the second iron slag outlet of the second separation device (9); the outlet of the drying device (11) is used to be connected to a subsequent sintering device; The inlet of the condenser (14) is connected to the light component outlet of the distillation tower (13), and the liquid phase material outlet of the condenser (14) is connected to the extractant inlet of the extraction device (8).

26. The system according to claim 25, wherein: The system further comprises: a homogenizer storage device (1), a recovered oil storage device (4), a wet slag storage device (6), an extractant storage device (7), an iron slag storage device (10), and a circulating oil storage device (12); the homogenizer storage device (1) is connected to the homogenizer inlet of the homogenizer (2) for introducing the homogenizer into the homogenizer (2); the inlet of the recovered oil storage device (4) is respectively connected to the first liquid phase outlet of the first separation device (3) and the heavy component outlet of the distillation tower (13); the outlet of the recovered oil storage device (4) is connected to the filter inlet of the filter device (5); the inlet of the wet slag storage device (6) is connected to the wet slag material outlet of the first separation device (3); the wet slag storage device (6) is connected to the wet slag material outlet of the first separation device (3); ) is connected to the wet slag material inlet of the extraction device (8); the extractant storage device (7) is provided with an extractant circulation inlet and an extractant circulation outlet, the extractant circulation outlet is connected to the extractant inlet of the extraction device (8), and the extractant circulation inlet is connected to the liquid phase material outlet of the condenser (14); the inlet of the iron slag storage device (10) is connected to the second iron slag outlet of the second separation device (9), and the outlet of the iron slag storage device (10) is connected to the inlet of the drying device (11); the inlet of the circulating oil storage device (12) is connected to the second liquid phase outlet of the second separation device (9), and the outlet of the circulating oil storage device (12) is connected to the distillation material inlet of the distillation tower (13).

27. The system according to claim 26, wherein: The first separation device (3) and the second separation device (9) are both centrifuges; The homogenizing device (2) and the extraction device (8) are both provided with a mechanical stirring device.

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