A papermaking production method for saving fiber raw materials

Abstract

The present invention relates to the technical field of papermaking, and discloses a papermaking production method for saving fiber raw materials. A wrapping agent is added in the papermaking process. The wrapping agent is a sizing agent formed by cooking a suspension obtained by mixing 3.57% - 12.5% starch, 12.5% - 21.4% modified composite calcium carbonate and 70% - 75% composite water. The adhesiveness of the starch suspension after cooking can wrap and adsorb the modified composite calcium carbonate dispersed and soaked in the starch sizing agent, so that the modified composite calcium carbonate will not aggregate and precipitate due to its own weight, thereby forming a stable starch-modified composite calcium carbonate wrapped colloid.

Description

Technical Field

[0001] The present invention relates to the technical field of papermaking, and particularly relates to a papermaking production method for saving fiber raw materials. Background Art

[0002] Directly adding calcium carbonate to pulp during the papermaking production and forming process will cause calcium carbonate to precipitate in the pipelines of the addition system, and it will flow away with the white water during the papermaking forming process, resulting in a low retention rate of calcium carbonate during the forming process. At the same time, the large amount of calcium carbonate lost not only burdens the entire flow system with calcium carbonate deposition, but also causes unstable addition of calcium carbonate.

[0003] In the prior art, adding calcium carbonate through a spray pipe will cause blockage of the pipeline nozzles due to the precipitation of calcium carbonate in the spray system, resulting in the problem of inability to continuously, evenly and stably add. Adding calcium carbonate wrapped with cationic starch, drying it and then adding it to the preparation system and then into the forming system will waste a large amount of energy, cause a long production process, complex production control procedures, easy pollution of material storage, increased material transportation and labor costs, etc.

[0004] In summary, how to solve the technical problems of calcium carbonate loss and precipitation in the flow system and the problem of efficiently and energy-savingly adding calcium carbonate filler through an effective and stable method is a process problem that the current papermaking industry urgently needs to solve. Summary of the Invention

[0005] The purpose of the present invention is to provide a papermaking production method for saving fiber raw materials. Through the adhesiveness of the starch suspension after cooking, the modified composite calcium carbonate dispersed and soaked in the starch glue can be wrapped and adsorbed, so that the modified composite calcium carbonate will not aggregate and precipitate due to its own weight, thus forming a stable starch-modified composite calcium carbonate wrapped colloid.

[0006] The above technical purpose of the present invention is achieved through the following technical solutions: A papermaking production method for saving fiber raw materials, in which a wrapping agent is added during the papermaking process. The wrapping agent is a sizing material formed by cooking a suspension obtained by mixing 3.57%-12.5% starch, 12.5%-21.4% modified composite calcium carbonate and 70%-75% composite water. The papermaking production process method includes the following steps:

[0007] S1: After the measured starch is prepared by adding water and stirring in a starch dissolution and stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 20-26%; starch addition is easy to accurately measure, the volume and power of the tank and stirrer required for starch dissolution are small, the energy consumption is low, and the energy-saving effect is remarkable. The starch is dissolved sufficiently, the dissolution concentration is the best, it will not form lumps or aggregates.

[0008] S2: Gradually add the starch suspension into the stirring tank for preparing the coating agent, and add 1 - 6 times the weight of the modified composite calcium carbonate powder of the suspended starch transported into the coating agent preparation tank; the modified composite calcium carbonate powder can be fully wrapped by the starch suspension, enabling the calcium carbonate and the starch to be fully and evenly mixed, and preventing the situation where the calcium carbonate powder sinks to the bottom due to its large mass ratio, resulting in incomplete mixing.

[0009] S3: Add composite water with a volume three times that of the suspended starch solution transported into the coating agent preparation tank into the stirring tank for preparing the coating agent. Continuously stir and mix the suspended starch and the modified composite calcium carbonate, and adjust the pH to be greater than 7; the stirring speed is 65 - 200 revolutions per minute. After continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of a viscous sizing agent to form the coating agent. If the stirring speed is too low, there will be a problem of calcium carbonate powder deposition. If it is too high, the energy consumption is high, the tank body shakes greatly, and the required volume of the tank body is large. The dissolution effect is the best and the mixing is the most sufficient after continuously stirring for 5 minutes, and there will be no deposited calcium carbonate.

[0010] S4: Transfer the cooked coating agent to the storage stirring tank for the coating agent through a pump for storage. The coating agent is transported by the pump through a pipeline equipped with a flow meter and a concentration meter to the inlet of the sizing pump, and then quantitatively transferred to the sizing mixing tank with ultraviolet light.

[0011] A further setting of the present invention is that during the cooking process in step S3, the stirrer continuously stirs at a speed of 20 - 30 revolutions per minute. When the temperature of the mixed solution after stirring and cooking reaches 90°C - 100°C, stop cooking when the mixed solution reaches the state of a viscous sizing agent to form the coating agent. Use the temperature to control the cooking time, so as to prevent the situation where a viscous sizing agent cannot be formed due to low temperature. When the temperature is higher than 90°C, the starch can be gelatinized to form the state of the sizing agent. When the temperature is higher than 100°C, it will waste energy and cause the sizing agent to overflow from the tank body.

[0012] A further setting of the present invention is that the modified composite calcium carbonate uses acrylic emulsion as a coupling agent, and the calcium carbonate is uniformly coated on the surface of the modified kaolin by introducing an air flow into the slurry to form the modified composite calcium carbonate.

[0013] By adopting the above technical solution.

[0014] A further setting of the present invention is that the modified composite calcium carbonate is prepared through the following steps:

[0015] S1: Mix and stir kaolin with water at a material - to - water ratio of 3g:10mL to obtain a kaolin slurry;

[0016] S2: Add styrene-acrylic emulsion to the slurry. After stirring for 0.5 h, continue to add calcium carbonate and polyethylene glycol phosphate ester to form a mixed slurry. React the mixed slurry in a carbon dioxide / nitrogen mixed gas for 1 hour;

[0017] S3: Filter, wash, and dry the slurry completed in step S2, and then dry it at 80 °C for 24 hours to obtain modified composite calcium carbonate.

[0018] A further setting of the present invention is that the mass ratio of calcium carbonate, kaolin, and styrene-acrylic emulsion is 1:5:1-3.

[0019] A further setting of the present invention is that the volume ratio of polyethylene glycol phosphate ester to water is 0.5-1:10.

[0020] By adopting the above technical solution, kaolin has a high whiteness, good covering power, and can improve the opacity of paper. A large number of unsaturated bonds Si-O- and Al-O- bonds are contained on the surface of kaolin. The Si-O- and Al-O- bonds on the cleavage plane will react with water to generate active Si-OH and Al-OH groups. Some calcium ions in calcium carbonate will undergo hydrolysis to finally form hydroxyl groups, active oxygen, and electron acceptor fields. Due to the dehydration between the OH groups on its surface, Si-O-Ca and Al-O-Ca bonds are formed, binding calcium carbonate and calcined kaolin together, and finally improving its ultraviolet absorption ability, whiteness, tear strength, and opacity.

[0021] Styrene-acrylic emulsion increases the viscosity of the dispersion system, avoiding the self-aggregation of kaolin and calcium carbonate particles. After dehydration and drying, the emulsion forms a film on the surface of larger kaolin particles, further fixing calcium carbonate particles.

[0022] A further setting of the present invention is that the composite water contains a nano-magnesium hydroxide solution with a mass concentration of 10-15 mg / mL.

[0023] By adopting the above technical solution, the existing technology usually uses single ultraviolet sterilization. Its bacteria are physically denatured, and the denatured proteins will self-repair, resulting in the re-proliferation of microorganisms, and it is impossible to sterilize thoroughly. The nano-magnesium hydroxide particles of the present invention enter the cell interior by endocytosis and release a large amount of hydroxide ions in the aqueous environment inside the cell, raising the pH value inside the cell to 10, destroying the normal neutral environment inside the cell, causing chemical denaturation of nucleic acids and proteins, and thus leading to the death of bacteria. Among them, ultraviolet light is added to the pulp mixing tank in the present invention, and ultraviolet light can promote the nano-sterilization efficiency. At the same time, the encapsulant prepared in the present invention can further improve its ultraviolet absorption ability, making the bactericidal effect of nano-magnesium hydroxide particles better.

[0024] The beneficial effects of the present invention are:

[0025] 1. After the starch suspension is cooked, its adhesiveness can wrap and adsorb the modified composite calcium carbonate dispersed and soaked in the starch glue, preventing the modified composite calcium carbonate from aggregating and precipitating due to its own weight, thus forming a stable starch-modified composite calcium carbonate wrapped colloid. During the transportation of the wrapped colloid, no precipitation will occur to block the transportation pipeline due to low flow rate. During the addition process of the wrapped colloid, it will not block the spray holes and pipelines of the headbox. The addition process of the wrapped colloid does not require the use of a calcium carbonate spraying system and can be directly added to the sizing and flow system, which is very convenient. During the transportation of the wrapped colloid through the flow system, it can adsorb the fine fibers in the pulp, increase the retention rate during the papermaking process, enhance the binding force between fibers, improve the yield of calcium carbonate during the papermaking and forming process, achieve the purpose of increasing the calcium carbonate content and reducing the calcium carbonate loss, and at the same time enhance the stability and uniformity of the calcium carbonate content in the finished paper; the calcium carbonate in the wrapped colloid is retained in the pulp to the greatest extent during the papermaking process, and the white water recovery system during the papermaking process will not be blocked due to the precipitation of the calcium carbonate in the wrapped colloid. It can save 15 - 30% of the wood fiber used in papermaking pulp, save a large amount of fiber raw materials, and can significantly reduce the production cost.

[0026] 2. Kaolin has a high whiteness, good covering power, and can improve the opacity of paper. A large number of unsaturated bonds Si - O - and Al - O - bonds are contained on the surface of kaolin. The Si - O - and Al - O - bonds on the cleavage plane will react with water to form reactive Si - OH and Al - OH groups. Some calcium ions in calcium carbonate will undergo hydrolysis to finally form hydroxyl groups, active oxygen, and an electron acceptor field. Due to the dehydration between the OH groups on its surface, Si - O - Ca and Al - O - Ca bonds are formed, binding calcium carbonate and calcined kaolin together, and finally improving its ultraviolet absorption ability, whiteness, tear strength, and opacity.

[0027] 3. In the prior art, single ultraviolet sterilization is usually used for sterilization. For the physical denaturation of bacteria, the denatured proteins will self - repair, resulting in the re - reproduction of microorganisms, and it is impossible to sterilize thoroughly. In the present invention, nano - magnesium hydroxide particles enter the cell interior through endocytosis and release a large amount of hydroxide ions in the aqueous environment inside the cell, raising the pH value inside the cell to 10, destroying the normal neutral environment inside the cell, causing chemical denaturation of nucleic acids and proteins, and thus leading to the death of bacteria. In the present invention, ultraviolet light irradiation is added to the pulp mixing tank. Ultraviolet light irradiation can promote the nano - sterilization efficiency. At the same time, the encapsulant prepared in the present invention can further improve its ultraviolet absorption ability, making the bactericidal effect of nano - magnesium hydroxide particles better. Detailed implementation mode

[0028] The technical solutions in the embodiments will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0029] Comparative Example 1,

[0030] A papermaking production method for saving fiber raw materials

[0031] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%;

[0032] S2: Gradually add the starch suspension into the encapsulant preparation stirring tank, and add 15% calcium carbonate which is 3 times the weight of the suspended starch transported into the encapsulant preparation tank;

[0033] S3: Add 75% water which is three times the volume of the suspended starch solution transported into the encapsulant preparation stirring tank, continuously stir and mix the suspended starch and calcium carbonate; the stirring speed is 65 - 200 revolutions per minute, and after continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of viscous sizing agent to form the encapsulant;

[0034] S4: The cooked encapsulant is transferred to the encapsulant storage stirring tank for storage by a pump, and the encapsulant is transported by the pump to the inlet of the pulp pump through a pipeline with a flow meter and a concentration meter, and then quantitatively transferred to the pulp mixing tank.

[0035] Comparative Example 2,

[0036] A papermaking production method for saving fiber raw materials

[0037] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%;

[0038] S2: Gradually add the starch suspension into the encapsulant preparation stirring tank, and add 15% calcium carbonate which is 3 times the weight of the suspended starch transported into the encapsulant preparation tank;

[0039] S3: Add 75% water which is three times the volume of the suspended starch solution transported into the encapsulant preparation stirring tank, continuously stir and mix the suspended starch and calcium carbonate; the stirring speed is 65 - 200 revolutions per minute, and after continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of viscous sizing agent to form the encapsulant;

[0040] S4: The cooked encapsulant is transferred to the encapsulant storage and stirring tank for storage by a pump. The encapsulant is transported by the pump through a pipeline equipped with a flow meter and a concentration meter to the inlet of the pulp pumping pump, and then quantitatively transferred to the pulp mixing tank with ultraviolet light irradiation.

[0041] Comparative Example 3

[0042] A papermaking production method for saving fiber raw materials

[0043] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution and stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%.

[0044] S2: The starch suspension is gradually added to the encapsulant preparation stirring tank, and 15% calcium carbonate three times the weight of the suspended starch transported into the encapsulant preparation tank is added.

[0045] S3: 75% compound water three times the volume of the suspended starch solution transported into the encapsulant preparation stirring tank is added to the encapsulant preparation stirring tank. The compound water contains a nano-aluminum hydroxide solution with a mass concentration of 12 mg / mL. Continuously stir and mix the suspended starch and calcium carbonate; the stirring speed is 65 - 200 revolutions per minute. After continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; the cooking can be stopped when the mixed solution reaches the state of a viscous sizing agent to form an encapsulant.

[0046] S4: The cooked encapsulant is transferred to the encapsulant storage and stirring tank for storage by a pump. The encapsulant is transported by the pump through a pipeline equipped with a flow meter and a concentration meter to the inlet of the pulp pumping pump, and then quantitatively transferred to the pulp mixing tank.

[0047] Example 1

[0048] A papermaking production method for saving fiber raw materials

[0049] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution and stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%.

[0050] S2: The starch suspension is gradually added to the encapsulant preparation stirring tank, and 15% modified composite calcium carbonate powder three times the weight of the suspended starch transported into the encapsulant preparation tank is added.

[0051] The modified composite calcium carbonate is prepared by the following steps:

[0052] 1: Kaolin with a material-water ratio of 3 g: 10 mL is mixed and stirred with water to obtain a kaolin slurry.

[0053] 2: Add styrene-acrylic emulsion to the slurry. After stirring for 0.5 h, continue to add calcium carbonate and polyethylene glycol phosphate ester to form a mixed slurry. React the mixed slurry in a carbon dioxide / nitrogen mixed gas for 1 hour. The volume ratio of polyethylene glycol phosphate ester to water is 0.5 - 1:10;

[0054] 3: Filter, wash, and dry the slurry after the reaction in step S2, and then dry it for 24 hours to obtain modified composite calcium carbonate. The mass ratio of calcium carbonate, kaolin, and styrene-acrylic emulsion is 1:5:1 - 3.

[0055] S3: Add 75% of the water with a volume three times that of the suspended starch solution transported into the coating agent preparation tank to the coating agent preparation stirring tank, and continuously stir and mix the suspended starch and modified composite calcium carbonate powder; the stirring speed is 65 - 200 revolutions per minute. After continuously stirring for 5 minutes, introduce steam to cook the mixed solution; stop cooking when the mixed solution reaches the state of viscous sizing material to form the coating agent;

[0056] S4: Transfer the cooked coating agent to the coating agent storage stirring tank for storage through a pump. The coating agent is transported by the pump to the inlet of the slushing pump through a pipeline equipped with a flow meter and a concentration meter, and then quantitatively transferred to the sizing pond.

[0057] Example 2,

[0058] A papermaking production method for saving fiber raw materials

[0059] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%;

[0060] S2: Gradually add the starch suspension to the coating agent preparation stirring tank, and add 15% calcium carbonate with a weight three times that of the suspended starch transported into the coating agent preparation tank;

[0061] S3: Add 75% of the composite water with a volume three times that of the suspended starch solution transported into the coating agent preparation tank to the coating agent preparation stirring tank. The composite water contains a nano-magnesium hydroxide solution with a mass concentration of 12 mg / mL. Continuously stir and mix the suspended starch and calcium carbonate; the stirring speed is 65 - 200 revolutions per minute. After continuously stirring for 5 minutes, introduce steam to cook the mixed solution; stop cooking when the mixed solution reaches the state of viscous sizing material to form the coating agent;

[0062] S4: Transfer the cooked coating agent to the coating agent storage stirring tank for storage through a pump. The coating agent is transported by the pump to the inlet of the slushing pump through a pipeline equipped with a flow meter and a concentration meter, and then quantitatively transferred to the sizing pond.

[0063] Example 3,

[0064] A papermaking production method for saving fiber raw materials

[0065] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution and stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%;

[0066] S2: Gradually add the starch suspension into the encapsulant preparation stirring tank, and add 15% calcium carbonate with a weight three times that of the suspended starch transported into the encapsulant preparation tank;

[0067] S3: Add 75% composite water with a volume three times that of the suspended starch solution transported into the encapsulant preparation stirring tank to the encapsulant preparation stirring tank. The composite water contains a nano-magnesium hydroxide solution with a mass concentration of 12 mg / mL. Continuously stir and mix the suspended starch and calcium carbonate; the stirring speed is 65 - 200 revolutions per minute. After continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of a viscous sizing agent to form an encapsulant;

[0068] S4: The cooked encapsulant is transferred to an encapsulant storage and stirring tank for storage by a pump. The encapsulant is transported by the pump to the inlet of a pulp pump through a pipeline equipped with a flow meter and a concentration meter, and then quantitatively transferred to a pulp mixing tank with ultraviolet light irradiation.

[0069] Example 4

[0070] A papermaking production method for saving fiber raw materials

[0071] S1: After 10% starch is prepared by adding water and stirring in a starch dissolution and stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 22%;

[0072] S2: Gradually add the starch suspension into the encapsulant preparation stirring tank, and add 15% modified composite calcium carbonate powder with a weight three times that of the suspended starch transported into the encapsulant preparation tank;

[0073] The modified composite calcium carbonate is prepared by the following steps:

[0074] 1: Mix and stir kaolin with a material-water ratio of 3 g: 10 mL with water to obtain a kaolin slurry;

[0075] 2: Add styrene-acrylic emulsion to the slurry. After stirring for 0.5 h, continue to add calcium carbonate and polyethylene glycol phosphate ester to form a mixed slurry, and react the mixed slurry in a carbon dioxide / nitrogen mixed gas for 1 hour. The volume ratio of polyethylene glycol phosphate ester to water is 0.5 - 1: 10;

[0076] 3: Filter, wash, and dry the slurry after the reaction in step S2, and then dry it for 24 hours to obtain modified composite calcium carbonate. The mass ratio of calcium carbonate, kaolin, and styrene-acrylic emulsion is 1:5:1-3.

[0077] S3: Add 75% composite water, which is three times the volume of the suspended starch solution fed into the encapsulant preparation tank, to the encapsulant preparation stirring tank. The composite water contains a nano-magnesium hydroxide solution with a mass concentration of 12 mg / mL. Continuously stir and mix the suspended starch and modified composite calcium carbonate; adjust the pH to be greater than 7, with a stirring speed of 65-200 revolutions per minute. After continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of viscous sizing material to form the encapsulant.

[0078] S4: Transfer the cooked encapsulant to the encapsulant storage stirring tank for storage through a pump. The encapsulant is pumped through a pipeline with a flow meter and a concentration meter to the inlet of the slushing pump, and then quantitatively transferred to the sizing pond.

[0079] Example 5

[0080] A papermaking production method for saving fiber raw materials

[0081] S1: After preparing 10% starch by adding water and stirring in a starch dissolution stirring tank, a starch suspension solution is obtained, and its starch content concentration is controlled at 22%.

[0082] S2: Gradually add the starch suspension to the encapsulant preparation stirring tank, and add 15% modified composite calcium carbonate powder, which is three times the weight of the suspended starch fed into the encapsulant preparation tank.

[0083] The modified composite calcium carbonate is prepared by the following steps:

[0084] 1: Mix and stir kaolin and water with a material-water ratio of 3 g:10 mL to obtain a kaolin slurry.

[0085] 2: Add the styrene-acrylic emulsion to the slurry. After stirring for 0.5 h, continue to add calcium carbonate and polyethylene glycol phosphate to form a mixed slurry, and react the mixed slurry in a carbon dioxide / nitrogen mixed gas for 1 hour. The volume ratio of polyethylene glycol phosphate to water is 0.5-1:10.

[0086] 3: Filter, wash, and dry the slurry after the reaction in step S2, and then dry it for 24 hours to obtain modified composite calcium carbonate, where the mass ratio of calcium carbonate, kaolin, and styrene-acrylic emulsion is 1:5:1-3.

[0087] S3: Add 75% compound water in the encapsulant preparation stirring tank, the volume of which is three times that of the suspended starch solution fed into the encapsulant preparation tank. The compound water contains a nano-magnesium hydroxide solution with a mass concentration of 12 mg / mL. Continuously stir and mix the suspended starch and the modified compound calcium carbonate; adjust the pH to be greater than 7, with a stirring speed of 65 - 200 revolutions per minute. After continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of viscous sizing agent to form the encapsulant.

[0088] S4: The cooked encapsulant is transferred to the encapsulant storage stirring tank for storage by a pump. The encapsulant is pumped through a pipeline equipped with a flow meter and a concentration meter to the inlet of the pulp pump, and then quantitatively transferred to the pulp mixing tank with ultraviolet light irradiation.

[0089] Perform performance test analysis on the paper samples with a basis weight of 100 g / m2 obtained in Comparative Examples 1 - 3 and Examples 1 - 5 to obtain the performance data results in the following table.

[0090] National Standard GB8940.1 - 88 stipulates that: based on the blue light of the D65 illuminant and the 45 / 0 illumination and observation conditions, the reference value of whiteness is based on the reflectance of the blue light with a wavelength of 457 nm irradiating on the magnesium oxide board. The whiteness of the paper is expressed as the percentage of the reflectance of this kind of light irradiating on the paper surface to the reflectance of the magnesium oxide board.

[0091] Add 15% calcium carbonate powder and 15% modified compound calcium carbonate powder to the pulp. The ratio of the retention amount of them in the paper to the filler amount in the stock is called the retention rate Rt. The approximate calculation formula for the filler retention rate is Rt = (ash content of the air-dried paper sheet / ash content of the air-dried stock) × 100%.

[0092] The paper samples are treated with four kinds of molds for 28 days. After the cultivation ends, take out the samples, and use the methods of visual observation and microscopic observation, and evaluate the mold-proof effect of the paper samples according to GB / T 24346—2009 in combination with the mold growth coverage area.

[0093] Table 1 Performance test analysis of the paper samples obtained in Comparative Examples 1 - 3 and Examples 1 - 5

[0094]

Claims

1. A papermaking production method for saving fiber raw materials, characterized in that: a wrapping agent is added during the papermaking process. The wrapping agent is a sizing agent formed by cooking a suspension obtained by mixing 3.57%-12.5% starch, 12.5%-21.4% modified composite calcium carbonate and 70%-75% composite water. The sum of the above components is 100%. The papermaking production process method includes the following steps: S1: After the measured starch is prepared by stirring with water in a starch dissolution and stirring tank, a starch suspension solution is obtained, and the starch content concentration is controlled at 20-26%; S2: Gradually add the starch suspension into the wrapping agent preparation stirring tank, and add 1-6 times the weight of the modified composite calcium carbonate powder of the suspended starch transported into the wrapping agent preparation tank; S3: Add three times the volume of the composite water of the suspended starch solution transported into the wrapping agent preparation tank into the wrapping agent preparation stirring tank, continuously stir and mix the suspended starch and the modified composite calcium carbonate, and adjust the pH to be greater than 7; the stirring speed is 65-200 revolutions per minute. After continuously stirring for 5 minutes, steam is introduced to cook the mixed solution; stop cooking when the mixed solution reaches the state of a viscous sizing agent to form a wrapping agent; S4: The cooked wrapping agent is transferred to the wrapping agent storage and stirring tank for storage by a pump. The wrapping agent is transported to the inlet of the pulp pump by the pump through a pipeline with a flow meter and a concentration meter, and then quantitatively transferred to a pulp mixing tank with ultraviolet light; the composite water is a nano-magnesium hydroxide solution containing a mass concentration of 10-15 mg / mL; the modified composite calcium carbonate uses styrene-acrylic emulsion as a coupling agent, and the calcium carbonate is uniformly coated on the surface of the modified kaolin by introducing an air flow into the slurry to form the modified composite calcium carbonate.

2. A papermaking production method for saving fiber raw materials according to claim 1, characterized in that: during the cooking process in step S3, the stirrer continuously stirs, and the stirring speed is 20-30 revolutions per minute. When the temperature of the mixed solution after stirring and cooking reaches 90℃-100℃, stop cooking when the mixed solution reaches the state of a viscous sizing agent to form a wrapping agent.

3. A papermaking production method for saving fiber raw materials according to claim 1, characterized in that: the modified composite calcium carbonate is prepared by the following steps: S1: Mix and stir kaolin with a material-water ratio of 3g:10mL with water to obtain a kaolin slurry; S2: Add styrene-acrylic emulsion to the slurry, stir for 0.5h, then continue to add calcium carbonate and polyethylene glycol phosphate to form a mixed slurry, and react the mixed slurry in a carbon dioxide / nitrogen mixed gas for 1 hour; S3: Filter, wash and dry the slurry after the reaction in step S2, and dry it for 24 hours to obtain the modified composite calcium carbonate.

4. A papermaking production method for saving fiber raw materials according to claim 3, characterized in that: the mass ratio of calcium carbonate, kaolin and styrene-acrylic emulsion is 1:5:1-3.

5. A papermaking production method for saving fiber raw materials according to claim 3, characterized in that: The volume ratio of the polyethylene glycol phosphate to water is 0.5 - 1:10.

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