Cotton lint degreasing method

Abstract

The present invention belongs to the technical field of cotton lint degreasing, and specifically relates to a cotton lint degreasing method, which uses clean water produced by fiber cement board production to degrease cotton lint, eliminating the direct use of strong alkaline substances. This mild degreasing method avoids the damage to the original physical state and characteristics of cotton lint fibers by traditional degreasing methods; through the fiber cement board production clean water pipeline, firstly, the degreasing situation can be judged according to the monitored pH changes, and corresponding adjustments can be made; secondly, the ratio can be adjusted at any time according to actual needs in production. When the clean water produced by fiber cement board production is insufficient, ordinary tap water and pH adjustment liquid are automatically added to timely replenish the degreasing pH actually required for the cotton lint, thereby ensuring degreasing efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of cotton lint degreasing, and particularly relates to a cotton lint degreasing method. Background Art

[0002] Cotton lint is widely used due to its high tensile strength and folding resistance, particularly in fiber-reinforced cement products and high-grade paper. For example, after degreasing, it can be used in the production of fiber-reinforced cement boards. After rinsing, it can also be used in demanding products such as banknote paper, bond paper, and cotton wool. Traditional degreasing processes, however, rely on specialized equipment such as scouring pots, continuous degreasing machines, and open-width degreasing machines, increasing investment costs. The continuous heating required also consumes significant energy. The large amount of strong alkaline substances required is not only costly but also potentially environmentally harmful. Summary of the Invention

[0003] In order to solve the problems raised in the background technology, the present invention provides a cotton lint degreasing method.

[0004] The technical solutions of the present invention are as follows:

[0005] The invention provides a cotton lint degreasing method, which uses clean water produced by fiber cement board to degrease the cotton lint.

[0006] The following steps are involved:

[0007] S1: The cotton lint to be processed is mixed with the clean water produced by the first fiber cement board in a first preset ratio and crushed;

[0008] S2: The crushed cotton wool is mixed with the first fiber cement board production water in a second preset ratio, stirred at a preset time interval for a preset length of time, and the pH is tested.

[0009] If the pH drop is less than the first preset value, the temperature of the stirred solution is detected.

[0010] If the detected temperature is lower than the preset temperature, the second fiber cement board production water is added, and the stirring is continued at the preset time interval and the preset length, and the pH is tested;

[0011] If the detected temperature is not lower than the preset temperature, continue stirring at the preset time interval and for the preset length of time to detect the pH;

[0012] If the pH drop is not less than the first preset value, then after adding the third fiber cement board production water, continue stirring at a preset time interval and for a preset length of time, and then test the pH;

[0013] When the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped to obtain absorbent cotton wool;

[0014] The first fiber cement board produces clean water, the second fiber cement board produces clean water, and the third fiber cement board produces clean water, which are obtained through the fiber cement board production clean water pipeline, specifically:

[0015] The fiber cement board production clear water pipeline comprises:

[0016] The clean water pipeline includes a first main pipe and a first fiber cement board production clean water branch pipe and a second fiber cement board production clean water branch pipe arranged in parallel, the outlet of the first main pipe is connected to the inlets of the first fiber cement board production clean water branch pipe and the second fiber cement board production clean water branch pipe; the second fiber cement board production clean water branch pipe is provided with a heating device;

[0017] The liquid distribution pipeline includes a second main pipe and a first liquid distribution branch pipe and a second liquid distribution branch pipe arranged in parallel. The inlet of the second main pipe is connected to the outlets of the first liquid distribution branch pipe and the second liquid distribution branch pipe; the second main pipe is provided with a pH detector, and the first liquid distribution branch pipe and the second liquid distribution branch pipe are provided with a proportional regulating valve.

[0018] In step S2, when the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped to obtain absorbent cotton wool, specifically:

[0019] When the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped and the sunken cotton wool is taken out as the degreased cotton wool;

[0020] When the pH drop amplitude is not less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped, the floating cotton wool is collected, and step S1 is performed to remove the sinking cotton wool as defatted cotton wool.

[0021] In step S2, the pH of the clean water produced by the first fiber cement board is 11.5-12 and the temperature is 35-37°C; the pH of the clean water produced by the second fiber cement board is 11.5-12 and the temperature is 40-42°C; the pH of the clean water produced by the third fiber cement board is not less than 12.

[0022] In step S1, the first preset ratio is: the amount of clean water added for producing the first fiber cement board is 2.5-3 times the weight of the cotton lint to be processed.

[0023] In step S2, the second preset ratio is: the amount of clean water added in the production of the first fiber cement board is 4.5-5 times the weight of the crushed cotton wool.

[0024] In step S2, the first preset amplitude is 0.5-0.8; the second preset amplitude is 0.1-0.3.

[0025] The invention also provides defatted cotton lint obtained by the cotton lint degreasing method.

[0026] The present invention also provides a use of the absorbent cotton wool in preparing fiber cement boards.

[0027] Beneficial effects

[0028] The present invention uses clean water produced by fiber cement board to degrease cotton lint, eliminating the direct use of strong alkaline substances. This mild degreasing method avoids the damage to the original physical state and properties of the cotton lint fiber by traditional degreasing methods. At the same time, while reducing the degreasing process and lowering production costs, it ensures the degreasing effect, meets the requirements of high-specification products, and complies with the concept of green production.

[0029] The present invention uses a fiber cement board production clean water pipeline. Firstly, the degreasing situation can be judged according to the monitored pH changes, so as to make corresponding adjustments. Secondly, the proportion can be adjusted at any time according to the actual needs in production. When the clean water for fiber cement board production is insufficient, ordinary tap water and pH adjustment liquid are automatically added to timely replenish the degreasing pH actually required for cotton wool, thereby ensuring degreasing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of a clean water pipeline for fiber cement board production provided by an embodiment of the present invention.

[0031] Description of reference numerals:

[0032] 1. Clean water pipeline, 11. First main pipe, 12. First fiber cement board production clean water branch pipe, 13. Second fiber cement board production clean water branch pipe, 2. Liquid distribution pipeline, 21. Second main pipe, 22. First liquid distribution branch pipe, 23. Second liquid distribution branch pipe. DETAILED DESCRIPTION

[0033] The following examples are intended to illustrate the present invention rather than to further limit the present invention.

[0034] Traditional degreasing methods primarily involve treating cotton lint with a sodium hydroxide solution, often referred to as "refining" or "singing." This is followed by multiple rinses to remove any residual alkali, or even the use of diluted sulfuric acid to neutralize any residual alkalinity. This treatment can easily damage the original physical state and properties of the cotton lint, hindering its further application, such as in fiber cement board, by reducing its flexural strength.

[0035] The present invention provides a method for degreasing cotton lint, which uses clean water produced by fiber cement board to degrease cotton lint. The method comprises the following steps:

[0036] S1: Cotton lint to be processed is mixed with clean water produced by the first fiber cement board in a first preset ratio and crushed.

[0037] Production clean water is recycled water that can be used for production after being precipitated in a water storage tank to remove large particles of impurities.

[0038] When the cotton lint fibers are longer than required, they are first crushed to shorten them. Preferably, the amount of clean water added to the first fiber cement board production process is 2.5-3 times the weight of the cotton lint. Crushing can be performed in a crusher, with the speed and time set appropriately according to actual needs. This allows the crushed cotton lint to be easily soaked and dispersed.

[0039] S2: The crushed cotton wool is mixed with the clean water produced by the first fiber cement board in a second preset ratio, such as in a circulating water tank, using continuous or intermittent circulation of water to ensure that the cotton wool can be fully and evenly soaked.

[0040] Preferably, the pH of the clean water used in the production of the first fiber cement board is 11.5-12 and the temperature is 35-37° C. to ensure the degreasing effect.

[0041] Furthermore, the amount of clean water added in the production of the first fiber cement board is 4.5-5 times the weight of the crushed cotton wool.

[0042] Stirring is performed at preset intervals for a preset duration, for example, every 30 minutes for 5 minutes each time, and pH is checked after each stirring. A certain degree of stirring can accelerate degreasing efficiency.

[0043] If the pH drop amplitude is less than the first preset amplitude, preferably, the first preset amplitude is 0.5-0.8, for example, when the pH is 11.4, the pH change is not large, which may be caused by measurement error or slow degreasing, then the temperature of the stirred solution is detected.

[0044] If the detected temperature is lower than the preset temperature, after adding the second fiber cement board production water, continue stirring for a preset time at a preset time interval and detect the pH; preferably, the pH of the second fiber cement board production water is 11.5-12 and the temperature is 40-42°C.

[0045] If the detected temperature is not lower than the preset temperature, continue stirring at the preset time interval and for the preset time length to detect the pH.

[0046] During the degreasing process, the degreasing time, degreasing temperature, and the pH of the water used to produce the first fiber cement board all affect the degreasing effect. Simply increasing the pH of the water used to produce the first fiber cement board will affect the practical application of the degreased cotton lint, and the degreasing effect is closely related to the pH of the water used to produce the first fiber cement board. Therefore, the present invention improves the degreasing efficiency of cotton lint by primarily treating the water used to produce the first fiber cement board, supplemented by temperature control, and adjusting the treatment method accordingly based on actual testing requirements.

[0047] If the pH drop is not less than the first preset value, the third fiber cement board production water is added, stirring is continued at preset time intervals and for preset lengths, and the pH is tested. The pH of the third fiber cement board production water is not less than 12.

[0048] During the degreasing process, the alkaline substances in the first fiber cement board production water and / or the second fiber cement board production water will be consumed, and the actual degreasing pH needs to be replenished in time to ensure the degreasing effect. The present invention maintains a stable pH by adding the third fiber cement board production water and preparing the stirring solution.

[0049] When the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped to obtain absorbent cotton wool, specifically:

[0050] When the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, preferably, the second preset amplitude is 0.1-0.3. For example, when the pH is 11.7, although the pH change is not large, but the stirring time is long enough and the cotton lint fibers no longer have obvious floating phenomenon, the stirring is stopped and the sunken cotton lint is taken out as the defatted cotton lint;

[0051] When the pH drop amplitude is not less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped, the floating cotton wool is collected, and step S1 is performed to remove the sinking cotton wool as defatted cotton wool.

[0052] The obtained defatted cotton linters are subjected to pulping treatment to obtain cotton linters fiber pulp after reaching the required beating degree and wet weight, and stored for subsequent use.

[0053] The first fiber cement board produces clean water, the second fiber cement board produces clean water, and the third fiber cement board produces clean water, which are obtained through the fiber cement board production clean water pipeline, specifically:

[0054] The fiber cement board production clear water pipeline comprises:

[0055] The clean water pipeline 1 includes a first main pipe 11 and a first fiber cement board production clean water branch pipe 12 and a second fiber cement board production clean water branch pipe 13 arranged in parallel. The outlet of the first main pipe 11 is connected to the inlets of the first fiber cement board production clean water branch pipe 12 and the second fiber cement board production clean water branch pipe 13; the second fiber cement board production clean water branch pipe 13 is provided with a heating device to heat the first fiber cement board production clean water to obtain the second fiber cement board production clean water, which shortens the degreasing time when processing cotton lint; and the first fiber cement board production clean water branch pipe 12 produces the first fiber cement board production clean water for use in steps S1 and step S2.

[0056] The liquid distribution line 2 includes a second main pipe 21 and a first liquid distribution branch pipe 22 and a second liquid distribution branch pipe 23 arranged in parallel. The inlet of the second main pipe 21 is connected to the outlets of the first liquid distribution branch pipe 22 and the second liquid distribution branch pipe 23. The second main pipe 21 is equipped with a pH meter, and the first liquid distribution branch pipe 22 and the second liquid distribution branch pipe 23 are equipped with proportional control valves. Among them, the first liquid distribution branch pipe 22 is used to distribute ordinary tap water, while the second liquid distribution branch pipe 23 is used to distribute pH adjustment liquid.

[0057] The outlets of the fiber cement board production clean water pipeline, i.e., the outlets of the first fiber cement board production clean water branch pipe 12, the outlets of the second fiber cement board production clean water branch pipe 13, and the outlet of the second main pipe 21 are connected to the circulating water tank to soak and disperse the crushed cotton wool.

[0058] The present invention uses a fiber cement board production clean water pipeline. Firstly, the degreasing situation can be judged according to the monitored pH changes, so as to make corresponding adjustments. Secondly, the proportion can be adjusted at any time according to the actual needs in production. When the clean water for fiber cement board production is insufficient, ordinary tap water and pH adjustment liquid are automatically added to timely replenish the degreasing pH actually required for cotton wool, thereby ensuring degreasing efficiency.

[0059] Example 1

[0060] (1) Cotton lint with an oil content of 3% to be processed is fed into a crusher, and clean water produced by the first fiber cement board production is added. The amount of clean water added is 2.5 times the weight of the cotton lint to be processed. The crusher speed is set to 600 rpm and the crushing time is 15 minutes.

[0061] (2) The crushed cotton wool is placed in a circulating water tank and mixed with the first fiber cement board production water in a ratio of 1:4.5 according to the weight of the crushed cotton wool. The pH of the first fiber cement board production water is 11.5 and the temperature is 35°C. Stir once every 30 minutes, and each stirring lasts for 5 minutes. After each stirring, the pH value is tested. If it is lower than 11.0, the third fiber cement board production water is added to maintain a stable pH value. When the total reaction time reaches the preset total time of 6 hours, the cotton wool fiber no longer shows obvious signs of floating, and the degreasing is completed.

[0062] Example 2

[0063] (1) Cotton lint with an oil content of 4% to be processed is fed into a crusher, and clean water produced by the first fiber cement board production is added. The amount of clean water added is 3 times the weight of the cotton lint to be processed. The crusher speed is set to 600 rpm and the crushing time is 15 minutes.

[0064] (2) The crushed cotton wool is placed in a circulating water tank and mixed with the first fiber cement board production water in a ratio of 1:5 according to the weight of the crushed cotton wool. The pH of the first fiber cement board production water is 12 and the temperature is 37°C. Stir once every 30 minutes, and each stirring lasts for 5 minutes. After each stirring, the pH value is tested. If it is lower than 11.2, the third fiber cement board production water is added to maintain a stable pH value. When the total reaction time reaches the preset total time of 6 hours, the cotton wool fiber no longer shows obvious signs of floating, and the degreasing is completed.

[0065] Example 3

[0066] (1) Cotton lint with an oil content of 4% to be processed is fed into a crusher, and clean water produced by the first fiber cement board production is added. The amount of clean water added is 3 times the weight of the cotton lint to be processed. The crusher speed is set to 600 rpm and the crushing time is 15 minutes.

[0067] (2) The crushed cotton wool is placed in a circulating water tank and mixed in a ratio of 1:5 between the weight of the crushed cotton wool and the amount of clean water added to the first fiber cement board production. The pH of the clean water for the first fiber cement board production is 12 and the temperature is 37°C. Stir once every 30 minutes, and each stirring lasts for 5 minutes. After each stirring, the pH value is tested. If it is not lower than 11.2 and the detection temperature of the stirring solution is lower than the preset temperature, a second fiber cement board production clean water with a temperature of 40°C is added to accelerate degreasing. Continue stirring and test the pH value after each stirring. If it is lower than 11.2, add a third fiber cement board production clean water to maintain a stable pH value. When the total reaction time reaches the preset total time of 6 hours, the cotton wool fiber no longer shows obvious signs of floating, and the degreasing is completed.

[0068] In addition, the present invention also provides degreased cotton wool obtained by the cotton wool degreasing method and use of the degreased cotton wool in preparing fiber cement boards. The specific application is to use absorbent cotton wool instead of part of the wood pulp fiber to prepare fiber cement board. For example, 78% siliceous material, 11% calcareous material, 2% absorbent cotton wool, 1% wood pulp fiber, 3% polyvinyl alcohol fiber, and 5% auxiliary filler are mixed in a homogenizer for 15 minutes to obtain a first slurry. The first slurry is pumped to a slurry storage tank, diluted to a solid content concentration of 15%, pumped into a headbox, dehydrated by a vacuum system, and wound into a blank on a forming cylinder. When the blank thickness reaches the set requirement, it is torn off to obtain a first blank with a thickness of 9.5 mm. After the first blank is stacked to no more than 1.1 m, it is pressed and dehydrated at a pressure of 75 MPa and a continuous pressurization time of 8 minutes to obtain a first slab. The first slab is pre-cured (temperature 40°C, time 14 hours), demolded, moisturizing curing (27 days), and dried (temperature 90°C, time 2 hours) in sequence to obtain a fiber cement board, the strength of which is not inferior to similar products obtained by using all-wood pulp fiber.

[0069] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for degreasing cotton lint, characterized in that: Degreasing cotton lint using fiber cement board production water includes the following steps: S1: The cotton lint to be processed is mixed with the clean water produced by the first fiber cement board in a first preset ratio and crushed; S2: The crushed cotton wool is mixed with the first fiber cement board production water in a second preset ratio, stirred at a preset time interval for a preset length of time, and the pH is tested. If the pH drop is less than the first preset value, the temperature of the stirred solution is detected. If the detected temperature is lower than the preset temperature, the second fiber cement board production water is added, and the stirring is continued at the preset time interval and the preset length, and the pH is tested; If the detected temperature is not lower than the preset temperature, continue stirring at the preset time interval and for the preset length of time to detect the pH; If the pH drop is not less than the first preset value, then after adding the third fiber cement board production water, continue stirring at a preset time interval and for a preset length of time, and then test the pH; When the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped to obtain absorbent cotton wool; the prepared absorbent cotton wool is used to prepare fiber cement board; The first fiber cement board produces clean water, the second fiber cement board produces clean water, and the third fiber cement board produces clean water, which are obtained through the fiber cement board production clean water pipeline, specifically: The fiber cement board production clear water pipeline comprises: The clean water pipeline (1) comprises a first main pipe (11) and a first fiber cement board production clean water branch pipe (12) and a second fiber cement board production clean water branch pipe (13) arranged in parallel, wherein the outlet of the first main pipe (11) is connected to the inlets of the first fiber cement board production clean water branch pipe (12) and the second fiber cement board production clean water branch pipe (13); the second fiber cement board production clean water branch pipe (13) is provided with a heating device; The liquid distribution pipeline (2) comprises a second main pipe (21) and a first liquid distribution branch pipe (22) and a second liquid distribution branch pipe (23) arranged in parallel, wherein the inlet of the second main pipe (21) is connected to the outlets of the first liquid distribution branch pipe (22) and the second liquid distribution branch pipe (23); the second main pipe (21) is provided with a pH detector, and the first liquid distribution branch pipe (22) and the second liquid distribution branch pipe (23) are provided with a proportional regulating valve.

2. The cotton lint degreasing method according to claim 1, wherein In step S2, when the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped to obtain absorbent cotton wool, specifically: When the pH drop amplitude is less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped and the sunken cotton wool is taken out as the degreased cotton wool; When the pH drop amplitude is not less than the second preset amplitude and the total reaction time reaches the preset total time, stirring is stopped, the floating cotton wool is collected, and step S1 is performed to remove the sinking cotton wool as defatted cotton wool.

3. The cotton lint degreasing method according to claim 1, wherein In step S2, the pH of the clean water produced by the first fiber cement board is 11.5-12 and the temperature is 35-37°C; the pH of the clean water produced by the second fiber cement board is 11.5-12 and the temperature is 40-42°C; the pH of the clean water produced by the third fiber cement board is not less than 12.

4. The cotton lint degreasing method according to claim 1, wherein In step S1, the first preset ratio is: the amount of clean water added for producing the first fiber cement board is 2.5-3 times the weight of the cotton lint to be processed.

5. The cotton lint degreasing method according to claim 1, characterized in that: In step S2, the second preset ratio is: the amount of clean water added in the production of the first fiber cement board is 4.5-5 times the weight of the crushed cotton wool.

6. The cotton lint degreasing method according to claim 1, characterized in that: In step S2, the first preset amplitude is 0.5-0.8; the second preset amplitude is 0.1-0.

3.

7. Degreased cotton linter obtained by the cotton linter degreasing method according to any one of claims 1 to 6.

8. Use of the absorbent cotton wool according to claim 7 in the preparation of fiber cement board.

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