Efficient production method of steel paper

Abstract

The invention discloses an efficient production method of steel paper, wherein the desalination time in the method of the invention is only a few minutes, or even less than 1 minute. Compared with the traditional method, the desalination time of steel paper can be greatly shortened, and the entire desalination process does not require frequent transfer between different liquid tanks, thus saving workload and unnecessary labor costs, and having the significant advantages of low cost and high efficiency.

Description

Technical Field

[0001] The invention relates to the field of special paper, and in particular to a method for efficiently producing steel paper. Background Art

[0002] As a special kind of paper, steel paper is made from cellulose and its derivatives as raw materials. Metal salts that have strong swelling and gelling properties on cellulose are used as treating agents. The steel paper base paper is treated and laminated to produce modified processed paper.

[0003] The production of steel paper involves the steps of gelling the base paper and laminating multiple layers of base paper, wherein the gelling is usually carried out using a zinc chloride solution. After the gelling treatment, a desalting step is further included to remove the zinc chloride salt component in the steel paper.

[0004] The traditional desalination method is to transfer the obtained raw steel paper to multiple desalination tanks with decreasing specific gravity or concentration of zinc chloride solution. For example, Chinese patent document CN 103103867 A discloses a steel paper board and its production process, wherein the desalination process is carried out in at least 10 desalination tanks, and the specific gravity of zinc chloride solution in each desalination tank is: 1.8, 1.5, 1.2, 1.0, 0.8, 0.5, 0.25, 0.15, 0.10 and 0.05. The processing time of each desalination tank is about 1 hour, and the whole desalination process takes more than 10 hours, or even about 1 day. At the same time, due to the need to transfer between different desalination tanks, the workload is increased, which greatly affects the efficiency of steel paper production.

[0005] In view of the above problems, various improvement schemes have been developed. For example, Chinese patent document CN 114808529 A discloses a steel paper production desalting device to solve the problem of low production efficiency of steel paper when desalting is performed in the steel paper production process. The method adopted is to set up a number of linearly arranged desalting tanks, a clean water pipe is set above the desalting tank, and a discharge pipe is set below the desalting tank; a desalting assembly is set above the desalting tank, and the desalting assembly includes a plurality of rolling rollers set above the desalting tank and a plurality of soaking rollers set at the bottom of the desalting tank. By setting up a plurality of rolling rollers and soaking rollers, the steel paper passes through the rolling rollers and soaking rollers in sequence during the desalting process, and the soaking rollers are set in the desalting tank, which makes the steel paper soaked in the desalting tank for desalting treatment. When the steel paper passes through a plurality of soaking rollers and rolling rollers smoothly, the steel paper has also completed the desalting process. In this way, production efficiency is guaranteed while ensuring production quality.

[0006] For another example, Chinese patent document CN104594127 A discloses a method for producing steel paper using sulfuric acid as a gelling agent. The method uses sulfuric acid as a gelling agent to gel and compound the steel paper base paper, thereby avoiding the use of zinc chloride. However, the method still requires deacidification treatment and still requires setting multiple gradients of different sulfuric acid concentrations for deacidification.

[0007] In summary, there is still a need to improve the production efficiency of steel paper, especially to improve the desalination efficiency after zinc chloride gelling treatment.

[0008] The information in the background technology is only for illustrating the general background of the present invention and should not be regarded as admitting or suggesting in any form that such information constitutes the prior art known to a person skilled in the art. Summary of the invention

[0009] In order to solve at least some of the technical problems in the prior art, the present invention provides an efficient production method of steel paper. Specifically, the present invention includes the following contents.

[0010] The present invention provides a method for efficiently producing steel paper, which comprises the following steps:

[0011] (1) soaking the multi-layer steel paper in a solution for 20 seconds to 30 minutes, wherein the solution is a 50-90 wt % zinc chloride solution, and then heating and pressurizing the soaked multi-layer steel paper; and

[0012] (2) The aged steel paper is transferred into a fluid, and the fluid is placed in an electric field, thereby causing the salt components in the steel paper to separate from the fluid and achieve desalination.

[0013] In certain embodiments, according to the efficient production method of steel paper of the present invention, the electric field is generated by direct current, and the direct current is 0.01-2A.

[0014] In certain embodiments, according to the method for efficiently producing steel paper of the present invention, the direction of the direct current is perpendicular to the surface of the steel paper.

[0015] In certain embodiments, according to the efficient production method of steel paper of the present invention, the fluid comprises pure water, clean water, tap water or purified river water, lake water or well water.

[0016] In certain embodiments, according to the method for efficiently producing steel paper of the present invention, the fluid is refluxed in a circulation manner after being treated.

[0017] In certain embodiments, according to the method for efficiently producing steel paper of the present invention, the time for which the steel paper is kept in the electric field is controlled to be from 1 second to 5 minutes.

[0018] In certain embodiments, according to the method for efficiently producing steel paper of the present invention, step (2) is carried out in a desalination tank, the height of the desalination tank is 5-50 cm, an anode is arranged at the top, and a cathode is arranged at the bottom. During the desalination treatment, the desalination tank is filled with fluid so that the steel paper is immersed in the fluid.

[0019] In certain embodiments, according to the efficient production method of steel paper of the present invention, the aging temperature is controlled at 25-40° C., and the aging time is 30-120 minutes.

[0020] In certain embodiments, the efficient production method of steel paper according to the present invention further comprises allowing the pulp to enter a pulping machine for pulping treatment, then enter a pulping box for mixing, further undergo a dilution and / or purification treatment, and undergo a dehydration treatment through a papermaking machine to form a wet paper web, and control the water content in the range of 4-8% through pressing and drying to obtain steel paper base paper.

[0021] In certain embodiments, according to the efficient production method of steel paper of the present invention, the slurry comprises 90-95 parts by weight of absorbent cotton fibers and 5-10 parts by weight of wood pulp short fibers, wherein the length of the absorbent cotton fibers is 2-25 mm, the length of the wood pulp short fibers is 1-2 mm, and the slurry does not contain glass fibers.

[0022] The desalination time in the method of the present invention is only a few minutes, or even less than 1 minute. Compared with the traditional method which takes more than 10 hours, the desalination time of steel paper can be greatly shortened, and the whole desalination process does not need to be frequently transferred between different tanks, thus saving workload and unnecessary labor costs, and having the excellent effect of low cost and high efficiency. DETAILED DESCRIPTION

[0023] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0024] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that the upper and lower limits of the scope and each intermediate value therebetween are specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0025] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as commonly understood by those skilled in the art to which the invention belongs. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0026] In this article, the term "steel paper", sometimes also called "hardened paper" or "paper steel", refers to a high-hardness special paper made of fiber material. It has excellent elasticity, toughness, wear resistance and corrosion resistance, as well as good electrical insulation and mechanical strength. It can be used as mechanical parts such as gaskets.

[0027] The present invention provides a method for efficiently producing steel paper, which comprises at least the following steps:

[0028] (1) soaking the multi-layer steel paper in a solution for 1-10 minutes, wherein the solution is a 50-90 wt % zinc chloride solution, and then heating and pressurizing the soaked multi-layer steel paper; and

[0029] (2) The aged steel paper is transferred into a fluid, and the fluid is placed in an electric field, thereby causing the salt components in the steel paper to separate from the fluid and achieve desalination.

[0030] Those skilled in the art will appreciate that numbers (1), (2), etc. are only for the purpose of distinguishing different steps and do not necessarily mean the order of the steps. As long as the purpose of the present invention can be achieved, the order of the above steps is not particularly limited. In addition, those skilled in the art will also appreciate that other steps or operations may be included before or after the above steps (1) and (2), or between the two steps, such as further optimizing and / or improving the method described in the present invention. Exemplarily, in addition to the above steps (1) and (2), the present invention may optionally further include step (3) an aging step.

[0031] Step (1):

[0032] Step (1) of the present invention is a zinc chloride gelling step, and the specific steps are not limited as long as zinc chloride is used to treat the steel paper. Exemplarily, step (1) comprises soaking the multi-layer steel paper in a solution for 20 seconds to 10 minutes, wherein the solution is a 50-90 wt% zinc chloride solution, and then heating and pressurizing the soaked multi-layer steel paper.

[0033] In the present invention, the number of layers of base paper when producing steel paper is not limited, and is generally 2-50 layers, preferably 3-40 layers, for example, 5 layers, 8 layers, 10 layers, 12 layers, 14 layers, 16 layers, 18 layers, 20 layers, 25 layers, 30 layers, 35 layers, etc. Those skilled in the art can select the required number of layers according to their needs.

[0034] In the present invention, the medicine solution is sometimes also referred to as zinc chloride solution, which refers to an agent used to swell and fluff the surface of the base paper. The amount of zinc chloride used affects the quality of the steel paper, and the general amount is 50-90% by weight, preferably 55-85% by weight, such as 56% by weight, 58% by weight, 60% by weight, 62% by weight, 64% by weight, 66% by weight, 68% by weight, 70% by weight, 72% by weight, 74% by weight, 76% by weight, 78% by weight, 80% by weight, 82% by weight, 84% by weight, etc. If the amount is too low, the gelling effect is poor, which affects the bonding between the base papers and further affects the interlayer bonding strength and other properties. On the other hand, if the amount is too high, the fiber tends to swell excessively, affecting the strength of the fiber, and may also cause the zinc content in the steel paper product to be too high, which will also affect the interlayer bonding strength and the insulation performance.

[0035] In the present invention, the time of the immersion treatment is not limited, and those skilled in the art can select a suitable time as needed. Exemplary time is 20 seconds to 10 minutes, preferably 30 seconds to 5 minutes, such as 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds, 90 seconds, 100 seconds, 110 seconds, 120 seconds, 130 seconds, 140 seconds, 150 seconds, 160 seconds, 170 seconds, 180 seconds, 190 seconds, 200 seconds, etc. If the treatment time is too short, the gelling effect tends to deteriorate, affecting the interlayer bonding. On the other hand, if the treatment time is too long, the fiber strength is affected, and then the tensile strength of the steel paper is affected.

[0036] In the present invention, the temperature during gelation is not limited, for example, the immersion gelation can be performed in the range of 15-40° C. Exemplary gelation temperatures include room temperature, 30° C., 35° C., 36° C., and the like.

[0037] In the present invention, after the gelling treatment, the soaked multi-layer steel paper base paper is heated and pressurized to form a strong bond between the layers. Heating and pressurizing can be performed separately or simultaneously. Heating and pressurizing at the same time is more conducive to the bonding between the base paper layers, so it is preferred. The heating temperature of the present invention is generally 30-90°C, for example, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, etc. When heating at high temperature, it is preferably heated under wet heat conditions. The pressurization of the present invention is generally performed by a pressure roller, and the pressure size is not limited.

[0038] Step (2):

[0039] Step (2) of the present invention is a desalination treatment step. The desalination treatment of the present invention causes the ions in the base paper to migrate through the electric field, and quickly move from the inside of the base paper to the fluid, thereby greatly improving the desalination effect and reducing the work intensity.

[0040] The desalination treatment of the present invention comprises transferring the aged steel paper into a fluid and placing the fluid in an electric field, thereby causing the salt components in the steel paper to separate from the fluid and achieve desalination.

[0041] In the present invention, the magnitude of the electric field is not limited, as long as the direction of the electric field remains substantially unchanged. The electric field of the present invention can be a variable electric field or a constant electric field.

[0042] In the present invention, the electric field is generally generated by direct current, and the size of direct current is generally 0.01-2A, such as 0.02A, 0.03A, 0.04A, 0.05A, 0.06A, 0.07A, 0.08A, 0.09A, 0.1A, 0.2A, 0.3A, 0.4A, 0.5A, 0.6A, 0.7A, 0.8A, 0.9A, 1.0A, 1.2A, 1.4A, 1.6A, 1.8A, etc. The size of direct current of the present invention can be kept constant or arbitrarily changed within the above range. Direct current within the above range can advantageously make the ions in the steel paper, especially the zinc ions, enter the fluid, and those skilled in the art can select the zinc chloride concentration in the steel paper, such as estimated, within the above range as needed. If the direct current is too large, the zinc chloride entering the fluid tends to electrolyze, thereby affecting the electrode life cycle and causing energy waste. On the other hand, if the DC current is too small, the ions in the steel paper may not migrate sufficiently.

[0043] In the present invention, the treatment time of the steel paper in the electric field is not limited, generally 1 second to 5 minutes. The salt component can be advantageously migrated to the fluid within the above time range. Those skilled in the art can select a suitable time according to the estimated concentration of zinc chloride in the steel paper, such as 5 seconds, 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds, 35 seconds, 40 seconds, 45 seconds, 50 seconds, 55 seconds, 60 seconds, 65 seconds, 70 seconds, 80 seconds, 90 seconds, 100 seconds, 110 seconds, 120 seconds, 2.5 minutes, 3 minutes, 4 minutes, 5 minutes, etc. If the treatment time is too long, the zinc chloride entering the fluid tends to be electrolyzed, thereby affecting the electrode life cycle and causing energy waste. On the other hand, if the treatment time is too short, the migration of zinc chloride may be insufficient.

[0044] In the present invention, in order to facilitate the migration of ions out of the steel paper, the angle between the direction of the electric field and the surface of the steel paper is preferably 45 0 More than 50 0 Above, 60 0 Above, 70 0Above, 80 0 The above is most preferably substantially vertical.

[0045] In the present invention, the fluid is not limited, and preferably the fluid is substantially free of salt components or ion components, except for the inevitable presence of a small amount of salt components or ions as impurities. The fluid of the present invention is preferably a polar solvent, and examples thereof include but are not limited to being selected from pure water, clear water, tap water or purified natural water, such as river water, lake water or well water. Purification of natural water generally refers to water after filtering to remove impurities.

[0046] In certain embodiments, the fluid after at least one desalination treatment is recycled. For example, a new fluid is replaced after 10 desalination treatments, preferably after 5 desalination treatments, and more preferably after 1 desalination treatment. The replaced fluid is recycled and can be further refluxed in a circulation manner for reuse after purification to remove salt components.

[0047] In certain embodiments, the present invention has desalination carried out in a desalination tank. The desalination tank of the present invention is preferably a flat elongated structure, and its height is generally 5-50cm, for example 6cm, 8cm, 10cm, 12cm, 14cm, 16cm, 18cm, 20cm, 22cm, 24cm, 26cm, 28cm, 30cm, 34cm, 36cm, 38cm, 40cm, 42cm, 44cm, 46cm, etc. If the height is too high, the spacing between the positive and negative electrodes tends to become larger, causing excessive power consumption, which is not conducive to reducing costs. On the other hand, if the height is too low, the spacing between the positive and negative electrodes tends to become smaller, then it is easy to produce electrical breakdown, causing steel paper damage.

[0048] In the present invention, the length and width of the desalination tank are not limited, and are at least equivalent to the size of the steel paper or a multiple thereof. The desalination tank of the present invention preferably has the anode disposed at the top and the cathode disposed at the bottom. This design is conducive to the zinc ions migrating from the steel paper to the bottom of the desalination tank, thereby avoiding further contact between the steel paper and the zinc ions when the steel paper is taken out of the fluid, thereby avoiding possible further contamination of the steel paper.

[0049] In the present invention, the cathode of the desalination tank is used to move cations such as zinc ions to it, and is preferably an inert electrode material, examples of which include but are not limited to platinum, gold, silver, copper, chromium, carbon, etc. Exemplary cathodes include metal electrodes such as platinum electrodes, gold electrodes, silver electrodes, carbon (graphite, graphene, glassy carbon, etc.) electrodes, copper electrodes, chromium electrodes, oxide electrodes such as NiFe2O4-based electrodes, SnO2-based electrodes, CeO2-coated electrodes, etc.

[0050] In the present invention, the anode of the desalination tank is used to allow anions such as chloride ions to move thereto, and its material is not limited, and any material can be used, including the above-mentioned inert electrode.

[0051] In certain embodiments, during the desalination process of the present invention, it is preferred that the desalination tank is filled with fluid, and the steel paper is immersed in the fluid, and preferably the steel paper is located approximately in the middle of the fluid in the desalination tank.

[0052] In some embodiments, the present invention further comprises the step of collecting gas generated during the electric field treatment. A certain amount of gas may be generated during the electric field treatment, and the generated gas may be collected when necessary to avoid potential danger, or desalination treatment may be performed under ventilation conditions.

[0053] Step (3):

[0054] Step (3) of the present invention is an aging treatment step, which is an optional step. Preferably, the aging treatment is carried out in an aging furnace, and the aging temperature is generally controlled at 25-40°C, such as 30°C, 32°C, 25°C, etc. The aging time is generally 30-120 minutes, such as 40 minutes, 50 minutes, 60 minutes, 70 minutes, 80 minutes, 90 minutes, etc. The aging time is generally related to the aging temperature. Generally, when the aging temperature is low, the aging treatment time is appropriately extended.

[0055] Step (4):

[0056] Step (4) of the present invention is a base paper production step, which is an optional step. Step (4) of the present invention exemplarily comprises allowing the pulp to enter a pulping machine for pulping, then enter a pulping box for mixing, further undergo dilution and / or purification, and undergo dehydration through a paper machine to form a wet paper web, and then control the water content in the range of 4-8% through pressing and drying to obtain steel paper base paper.

[0057] In the present invention, beating is performed in a pulping machine to increase the flexibility and interweaving of the fibers. The beating can be performed using a disc refiner, a conical refiner, or the like. The beating degree is controlled to be 15-25°SR, such as 16, 18, 20, 22, 24°SR; the wet weight is 8-18g, such as 9, 10, 12, 14, 16g, or the like. When preparing the slurry, the slurry is diluted to a solid content of 40-60% by weight. The purification treatment is used to remove fine impurities and particles. The purification method is not limited, and can be performed by, for example, precipitation, filtration, or flotation. Precipitation is the process of causing impurities to settle to the bottom by gravity. Filtration is the process of using filter media such as filter cloth or filter screen to intercept impurities. Flotation is the process of using bubbles to bring impurities to the surface of the slurry and remove them. The present invention can use any of the above methods or a combination of multiple methods for purification.

[0058] In the present invention, dehydration is a process of removing moisture from the net by vacuum to form wet paper. The pressing of the present invention further removes moisture. After pressing, the paper is transferred from the wet net to the wet machine, where heat transfer is used to achieve the purpose of drying, and then hot air is used to dry the paper to form base paper. In the present invention, the wet net can reduce the damage of the wet paper during the transfer process and maintain the flatness of the paper. The wet paper undergoes a wetting process on the wet net, which makes the cellulose fibers more closely bonded, which is beneficial to the heat transfer effect in the subsequent drying process. Next, the purpose of drying is achieved by heat transfer in the wet machine. The wet machine is the main equipment for drying paper. The wet paper is heated by hot pressing rollers and hot air to evaporate the moisture in the paper. In the wet machine, the wet paper is fed into the pressing area between the hot pressing rollers. Under high pressure and high temperature, the moisture is squeezed out of the paper, making the surface of the paper dry. At the same time, the paper is heated by hot air to increase the heat transfer effect and speed up the drying of the paper.

[0059] In certain embodiments, the slurry of the present invention comprises two fibers of different lengths, namely long fibers and short fibers, preferably, the short fibers have a greater hardness than the long fibers. The present invention has found that when the long fibers and the short fibers are respectively hydrophilic fibers, preferably the hydrophilic properties of the two fibers are the same or similar, it is more conducive to promoting the combination between the two different fibers, thereby improving the tensile strength of the steel paper.

[0060] The long fiber of the present invention refers to a fiber having a longer length relative to another fiber in the steel-paper pulp composition. The length of the long fiber is generally controlled within the range of 2-25 mm, such as 3 mm, 5 mm, 6 mm, 8 mm, 10 mm, 12 mm, 15 mm, 16 mm, 18 mm, 20 mm, 22 mm, and 24 mm. Those skilled in the art will appreciate that the above length range is only exemplary, and other suitable lengths may be selected as required, such as 26 mm, 27 mm, 28 mm, 29 mm, 30 mm, etc. Preferably, the long fiber of the present invention is a flexible fiber, that is, it is more flexible than the short fiber.

[0061] In the present invention, the amount of the long fibers is 90 to 95 parts by weight, such as 91 parts by weight, 92 parts by weight, 93 parts by weight, 94 parts by weight, and 95 parts by weight. When the amount of the long fibers is within the above range, the contact between the long fibers can be ensured, while the regulating effect of the short fibers can be fully exerted.

[0062] In certain embodiments, the long fibers of the present invention are absorbent cotton fibers. Compared with non-absorbent cotton fibers, the combination of absorbent cotton fibers and the short fibers of the present invention can further improve the insulation performance of the steel paper fiber. The reason for this is unclear and is not bound by theoretical explanations. It is speculated that the possible reason is that the absorbent cotton fibers have a higher hydrophilicity, which is comparable to the hydrophilicity of the short fibers, especially wood pulp fibers, which is conducive to the combination of the fibers during hot pressing, thereby improving the strength and thus improving the insulation.

[0063] The length of the staple fibers of the present invention is generally selected in the range of 1-2 mm. In certain embodiments, the length of the staple fibers of the present invention is 1 / 3 to 1 / 10 of the length of the long fibers, such as 1 / 4, 1 / 5, 1 / 6, 1 / 7, 1 / 8, 1 / 9, etc.

[0064] In the present invention, preferably, the short fibers have a higher hardness, which may also be referred to as hard fibers, so that when forming steel paper pulp, the hard fibers can be randomly dispersed among a plurality of long fibers and promote bonding between the fibers during subsequent processing.

[0065] In the present invention, the amount of the short fibers is 5-10 parts by weight, such as 6 parts by weight, 7 parts by weight, 8 parts by weight, and 9 parts by weight. When the amount of the short fibers is within the above range, the short fibers can give full play to the hardness of the short fibers without affecting the bonding between the long fibers. If the amount of the short fibers is too high, the short fibers tend to be dispersed in large quantities between the long fibers, which is not conducive to improving the contact and bonding between the long fibers, affecting the toughness of the steel paper. On the other hand, if the amount is too low, the long fibers tend to be excessively contacted, which is not conducive to improving the hardness of the steel paper.

[0066] In certain embodiments, the short fibers of the present invention are wood pulp fibers. That is, fibers made from woody plants as raw materials. Wood pulp fibers can be virgin wood pulp, recycled wood pulp, or a mixture of the two in any proportion. The type of woody plant used as the raw material is not limited, and any woody plant known in the art can be selected, and examples thereof include but are not limited to broad-leaved plants such as birch, poplar, basswood, eucalyptus, maple, and coniferous plants such as fish-scale spruce, sand pine spruce, stinking fir, Korean pine, larch, and masson pine.

[0067] In certain embodiments, the wood pulp fiber of the present invention preferably has a kappa number of 5-20, such as 6, 7, 8, 9, 10, 12, 14, 15, 16, 18, etc. The present invention has found that when the kappa number is within the above range, the insulation performance of the steel paper produced can be greatly improved, and the density is higher. If the kappa number is too high, the insulation performance of the steel paper tends to decrease significantly.

[0068] Example 1

[0069] 1. The multi-layer steel paper is simultaneously conveyed into a 70% zinc chloride solution through a conveying roller for soaking for 1.5 minutes. Next, the soaked multi-layer paper is heated at 30-40°C for 20-30 minutes to further penetrate the zinc chloride and gelatinize the fibers. Then, the multi-layer paper is hot-pressed to tightly bond the multi-layer paper to form a semi-finished product.

[0070] Second, send the semi-finished product into the aging furnace and carry out aging treatment at 20-40℃ for about 50 minutes to improve the stability of the internal structure of the steel paper. If necessary, cool it to room temperature first.

[0071] 3. After aging, keep ventilation, put the steel paper horizontally into the desalination tank filled with clean water. The height of the desalination tank is about 10cm. Set the graphene electrode as the anode on the top of the desalination tank and the graphene electrode as the cathode on the bottom. Adjust the position of the steel paper in the clean water so that it is completely immersed in the water. Apply 0.02A direct current to the top and bottom of the desalination tank for 30 seconds. Then transfer it to the clean water tank for washing, take it out and dry it until the moisture content is less than 5%.

[0072] Take about 2g of absolutely dry paper sample and soak it in 5ml sulfuric acid until it is completely carbonized. Then add hydrogen peroxide solution until the solution is clear and heat to dryness. Then add 20ml hydrochloric acid to dissolve and make up to 1000ml (pH 8.5-9.0). The zinc content of the steel paper is 0.013% at 620nm by UV-visible spectrophotometry.

[0073] Example 2

[0074] 1. The multi-layer steel paper is simultaneously conveyed into a 60% zinc chloride solution through a conveying roller for immersion for 1.5 minutes. Next, the soaked multi-layer paper is heated at 30-40°C for 20-30 minutes to further penetrate the zinc chloride and gelatinize the fibers. Then, the multi-layer paper is hot-pressed to tightly bond the multi-layer paper to form a semi-finished product.

[0075] Second, send the semi-finished product into the aging furnace and carry out aging treatment at 20-40℃ for about 50 minutes to improve the stability of the internal structure of the steel paper. If necessary, cool it to room temperature first.

[0076] 3. After aging, keep ventilation, put the steel paper horizontally into the desalination tank filled with clean water. The height of the desalination tank is about 10cm. Set the graphene electrode as the anode on the top of the desalination tank and the graphene electrode as the cathode on the bottom. Adjust the position of the steel paper in the clean water so that it is completely immersed in the water. Apply 0.02A direct current to the top and bottom of the desalination tank for 30 seconds. Then transfer it to the clean water tank for washing, take it out and dry it until the moisture content is less than 5%.

[0077] Take about 2g of absolutely dry paper sample and soak it in 5ml sulfuric acid until it is completely carbonized. Then add hydrogen peroxide solution until the solution is clear and heat to dryness. Then add 20ml hydrochloric acid to dissolve and make up to 1000ml (pH 8.5-9.0). The zinc content of the steel paper is 0.009% at 620nm by UV-visible spectrophotometry.

[0078] Example 3

[0079] 1. The multi-layer steel paper is simultaneously conveyed into a 60% zinc chloride solution through a conveying roller for immersion for 1.5 minutes. Next, the soaked multi-layer paper is heated at 30-40°C for 20-30 minutes to further penetrate the zinc chloride and gelatinize the fibers. Then, the multi-layer paper is hot-pressed to tightly bond the multi-layer paper to form a semi-finished product.

[0080] Second, send the semi-finished product into the aging furnace and carry out aging treatment at 20-40℃ for about 50 minutes to improve the stability of the internal structure of the steel paper. If necessary, cool it to room temperature first.

[0081] 3. After aging, keep ventilation, put the steel paper horizontally into the desalination tank filled with clean water. The height of the desalination tank is about 10cm. Set the graphene electrode as the anode on the top of the desalination tank and the graphene electrode as the cathode on the bottom. Adjust the position of the steel paper in the clean water so that it is completely immersed in the water. Apply 0.02A direct current to the top and bottom of the desalination tank for 50 seconds. Then transfer it to the clean water tank for washing, take it out and dry it until the moisture content is less than 5%.

[0082] Take about 2g of absolutely dry paper sample and soak it in 5ml sulfuric acid until it is completely carbonized. Then add hydrogen peroxide solution until the solution is clear and heat to dryness. Then add 20ml hydrochloric acid to dissolve and make up to 1000ml (pH 8.5-9.0). The zinc content of the steel paper is 0.006% at 620nm by UV-visible spectrophotometry.

[0083] Comparative Example

[0084] 1. The multi-layer steel paper is simultaneously conveyed into a 60% zinc chloride solution through a conveying roller for immersion for 1.5 minutes. Next, the soaked multi-layer paper is heated at 30-40°C for 20-30 minutes to further penetrate the zinc chloride and gelatinize the fibers. Then, the multi-layer paper is hot-pressed to tightly bond the multi-layer paper to form a semi-finished product.

[0085] Second, send the semi-finished product into the aging furnace and carry out aging treatment at 20-40℃ for about 50 minutes to improve the stability of the internal structure of the steel paper. If necessary, cool it to room temperature first.

[0086] 3. After aging, the steel paper is sequentially placed into 8 cleaning tanks with gradually decreasing concentrations and finally pure water for desalination treatment. The zinc chloride concentrations in the cleaning tanks are 50%, 25%, 15%, 8%, 4%, 2%, 1%, 0.5%, 0.05%, and 0. The desalination treatment time of each cleaning tank is controlled within 30 minutes, and the paper is taken out and dried to a water content of less than 5%.

[0087] Take about 2g of absolutely dry paper sample and soak it in 5ml sulfuric acid until it is completely carbonized. Then add hydrogen peroxide solution until the solution is clear and heat to dryness. Then add 20ml hydrochloric acid to dissolve and make up to 1000ml (pH 8.5-9.0). The zinc content of the steel paper is 0.014% at 620nm by UV-visible spectrophotometry.

[0088] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the disclosed exemplary embodiments. Various adjustments or changes may be made to the exemplary embodiments of the present specification without departing from the scope or spirit of the present invention. The scope of the claims should be based on the broadest interpretation to cover all modifications and equivalent structures and functions.

Claims

1. An efficient production method of steel paper, characterized in that: The following steps are involved: (1) soaking the multi-layer steel paper in a solution for 20 seconds to 30 minutes, wherein the solution is a 50-90 wt % zinc chloride solution, and then heating and pressurizing the soaked multi-layer steel paper; and (2) transferring the aged steel paper into a fluid so that the fluid is placed in an electric field, thereby causing the salt components in the steel paper to separate from the fluid and achieve desalination. The electric field is generated by direct current, and the direct current is 0.01-2A. The steel paper is kept in the electric field for 1 second to 5 minutes. The fluid includes pure water or tap water. Step (2) is performed in a desalination tank. The desalination tank is 5-50 cm high, with an anode disposed on the top and a cathode disposed on the bottom. During the desalination treatment, the desalination tank is filled with fluid so that the steel paper is immersed in the fluid.

2. The efficient production method of steel paper according to claim 1, characterized in that: The direction of the direct current is perpendicular to the surface of the steel paper.

3. The efficient production method of steel paper according to claim 1, characterized in that: The fluid is circulated back after being treated.

4. The efficient production method of steel paper according to claim 1, characterized in that: The aging temperature is controlled at 25-40°C and the aging time is 30-120 minutes.

5. The efficient production method of steel paper according to claim 1, characterized in that: The method further comprises allowing the pulp to enter a pulping machine for pulping treatment, and then enter a pulping box for mixing, and further undergoing dilution and / or purification treatment, and undergoing dehydration treatment through a papermaking machine to form a wet paper web, and controlling the water content in the range of 4-8% through pressing and drying to obtain steel paper base paper.

6. The efficient production method of steel paper according to claim 5, characterized in that: The slurry comprises 90-95 parts by weight of absorbent cotton fibers and 5-10 parts by weight of wood pulp short fibers, wherein the absorbent cotton fibers have a length of 2-25 mm, the wood pulp short fibers have a length of 1-2 mm, and the slurry does not contain glass fibers.