Process for recycling aramid spinning blowdown

Abstract

The application provides a process for recycling aramid spinning flush material, and belongs to the technical field of high-risk solid waste recycling, and aims to solve the technical problem that PPTA resin is easy to degrade during neutralization and washing recovery.The recycling process comprises the following steps: (1) collecting aramid spinning flush material lumps and cooling at low temperature; (2) soaking the cooled flush material lumps in ice water / ice slurry, replacing the ice water / ice slurry for multiple times until the leaching liquid is weakly acidic and stable; crushing the flush material lumps; (3) soaking the crushed flush material lumps in weakly alkaline ice water / ice slurry to neutralize residual acid, and then crushing the flush material lumps again by using a crushing device, and washing, drying and obtaining recycled PPTA resin particles.The application realizes harmless treatment and resource utilization of the aramid spinning flush material containing a large amount of sulfuric acid and aramid resin generated during aramid spinning, improves economic benefits and reduces environmental pollution.

Description

Technical Field

[0001] This invention belongs to the technical field of high-risk solid waste recycling, and particularly relates to the recycling of aramid spinning punching material. Background Technology

[0002] Para-aramid (PPTA) is a high-performance chemical fiber made from PPTA resin polymerized from p-phenylenediamine and terephthaloyl chloride monomers through spinning. Its strength, modulus, and toughness are significantly superior to steel wire, while its density is only about 20% of that of steel wire. With its core advantages of being lightweight and high-strength, it occupies an irreplaceable position in key fields such as national defense, aerospace, automotive industry, and rope and optical cable, becoming an indispensable basic material for high-end manufacturing.

[0003] Currently, the mainstream manufacturing process for PPTA fibers is dry-jet wet spinning. This involves mixing polymerized PPTA resin powder with concentrated sulfuric acid in a specific ratio to form a spinning slurry, which is then degassed before being fed into spinning equipment. However, this production process inevitably generates "waste material" that cannot be used for spinning. This waste contains both highly corrosive concentrated sulfuric acid and valuable PPTA resin. Improper handling not only wastes resources but may also pose environmental risks, thus necessitating an efficient centralized treatment solution.

[0004] Existing treatment technologies have significant shortcomings, making it difficult to balance environmental protection and resource recycling efficiency: First, although the traditional "alkali neutralization + incineration and landfill" process can treat corrosive components, the incineration process releases a large amount of harmful waste gas, which seriously pollutes the atmospheric environment and contradicts the development concept of green chemistry; Second, although the method of using alkaline washing to recover PPTA resin attempts to achieve resource reuse, the molecular weight of the recovered resin will be greatly reduced, which cannot meet the requirements of subsequent spinning processes, resulting in a significant reduction in recycling value.

[0005] In-depth analysis reveals that resin degradation is the core obstacle to recycling efficiency. On the one hand, PPTA resin is inherently prone to chemical degradation in extreme environments of strong acids or alkalis. On the other hand, the precipitation of concentrated sulfuric acid during treatment, its neutralization with alkali, and the dilution of sulfuric acid release a large amount of heat, keeping the recycled PPTA resin blocks at high temperatures. This temperature effect further accelerates the degradation rate of PPTA resin, creating a dual destructive mechanism of "chemical corrosion + high temperature aggravation." Therefore, how to achieve efficient washing and neutralization of sulfuric acid from waste PPTA resin blocks while minimizing degradation losses during recycling has become a critical challenge that urgently needs to be overcome in the field of PPTA resin particle recycling technology. Summary of the Invention

[0006] To address the technical problem of PPTA resin being easily degraded during alkaline washing and recycling, this invention proposes a process for recycling and reusing aramid spinning flushing material. This process neutralizes sulfuric acid in the flushing material during aramid spinning while simultaneously improving the quality of the recycled PPTA resin, achieving the goal of harmless and resource-based treatment of acidic solid waste.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A process for recycling and reusing aramid spinning punching material includes the following steps:

[0009] (1) Collect the aramid spinning punching material blocks and cool them down;

[0010] (2) Soak the cooled car wash material blocks in ice water / ice slurry, replacing the ice water / ice slurry multiple times until the leachate is weakly acidic and stable; then break the car wash material blocks.

[0011] (3) The crushed PPTA resin blocks were soaked in weakly alkaline ice water / ice slurry until the pH of the leachate was close to neutral. Then, they were crushed again using a crushing device, washed and dried to obtain recycled PPTA resin particles.

[0012] In step (1), the flushing material is cooled to below 5°C to buffer the release of sulfuric acid from the flushing material through dilution.

[0013] In step (2), the mass ratio of the flushing material block to ice water / ice slurry is 1:5~20, so as to ensure the amount of sulfuric acid precipitated as much as possible while absorbing the sulfuric acid dilution and heat release.

[0014] In step (2), after the pH of the leachate is stabilized at 4-6, the car wash material blocks are broken up. At this time, the residual acid in the car wash material blocks is very small, and the soaking can be terminated.

[0015] In step (2), the diameter of the crushed rubber block is 1~5 cm, which facilitates the precipitation and washing of residual acid.

[0016] The leachate from step (2) is collected, and then a neutralizing agent is added to neutralize the acidity of the leachate, resulting in a neutral waste liquid.

[0017] The neutralizing agent is a base or salt that can react with sulfuric acid, including one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium bicarbonate, sodium carbonate, and calcium carbonate.

[0018] In step (3), the pH of the weakly alkaline ice water / ice slurry is 7-9, which neutralizes the residual acid.

[0019] In step (3), the mass ratio of the crushed car wash block to the alkaline ice water / ice slurry is 1:5~20.

[0020] The weakly alkaline ice water / ice slurry is prepared by adding an alkaline reagent, which is one or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium bicarbonate, and sodium carbonate.

[0021] The beneficial effects of this invention are:

[0022] (1) Addressing the triple challenges of high cost, significant environmental risk, and severe resource waste in the treatment of aramid spinning waste (containing a large amount of sulfuric acid and aramid), this invention achieves safe and efficient recycling of high-risk solid waste through the synergistic cooperation of three steps: cooling and buffering, soaking in ice water / ice slurry to dissipate acid and cool down, and neutralizing residual acid with alkaline ice water / ice slurry. First, the waste block is cooled to buffer the large amount of heat released during sulfuric acid precipitation, preventing local high temperature from causing damage to the waste block and protecting the aramid molecular structure from being destroyed, thus facilitating subsequent sulfuric acid precipitation and aramid recycling. After cooling, ice water / ice slurry soaking is used, which can maximize the precipitation of sulfuric acid in the waste block by utilizing the low temperature environment, improve the sulfuric acid recovery rate, and absorb the heat continuously released during the sulfuric acid precipitation process in real time, further consolidating the cooling effect, avoiding heat accumulation that could lead to molecular structure damage, and preventing degradation due to temperature fluctuations. Finally, by immersing in alkaline ice water / ice slurry to neutralize residual acid, residual sulfuric acid that has not been completely precipitated in the recycled aramid material can be precisely removed, completely eliminating the acid hazard. Furthermore, the low-temperature characteristics of alkaline ice water / ice slurry can extend the cooling effect of the first two steps, avoiding the exothermic neutralization reaction from affecting the quality of aramid and ensuring the high quality of recycled aramid.

[0023] (2) This invention not only solves the problem of recycling and utilizing highly hazardous acidic solid waste, but also upgrades the treatment of highly hazardous acidic solid waste from "harmless treatment" to "resource transformation", reducing the cost of waste disposal from the source and eliminating the waste of aramid resources. This not only significantly improves the economic benefits of enterprises, but also minimizes environmental pollution, helps the aramid industry chain to open up the solid waste recycling link, and promotes the high-quality development of the entire industry towards green and sustainable development. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 It is a punching material block for aramid spinning.

[0026] Figure 2Comparison of the morphology of recovered aramid particles in the recycling process; (A) Original synthetic PPTA resin particles; (B) PPTA resin particles recovered in Example 1; (C) PPTA resin recovered in Comparative Example 1; (D) Aramid resin recovered in Comparative Example 4.

[0027] Figure 3 The specific viscosity of the aramid resin particles recovered in the recycling process.

[0028] Figure 4 Thermogravimetric analysis curves of aramid resin particles recovered in the recycling process.

[0029] Figure 5 XRD comparison of aramid resin particles recovered for recycling and reuse processes with virgin resin.

[0030] Figure 6 This is a process flow diagram for the recycling and reuse of aramid spinning punching material. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1

[0033] A process for recycling and reusing aramid spinning punching material, such as... Figure 1 As shown, the specific process includes the following steps:

[0034] 1) Collection and soaking

[0035] Aramid spinning filler material is collected in a PTFE container, such as a granulated block of filler material. Figure 1 As shown, the material was then cooled and stored at a low temperature below 5°C. 5.2 kg of the cooled material was placed in a 1:10 ice slurry and soaked for 1 day, during which the ice slurry was replaced with fresh ice slurry several times. The pH of the leachate was measured to be 4, and the pH was measured again after 3 hours and remained unchanged.

[0036] 2) Neutralization waste liquid and material washing

[0037] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 1-5cm pieces; collect the leachate and washing waste liquid, and gradually add sodium hydroxide until the leachate is neutral.

[0038] 3) Crushing

[0039] After being initially crushed into small blocks, the slag was added again at a mass ratio of 1:10 to an ice slurry containing sodium bicarbonate with a pH of 8-9 and soaked for 1 day. The slag was then filtered, washed, and dried. The dried blocks were then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0040] Example 2

[0041] A process for recycling and reusing aramid spinning punching material, specifically including the following steps:

[0042] 1) Collection and soaking

[0043] The aramid spinning feed material was collected in a polytetrafluoroethylene container and then cooled and stored at a low temperature below 5°C. 4.8 kg of the cooled feed material was placed in a 1:10 ice slurry and soaked for 1 day, during which the ice slurry was replaced with fresh ice slurry several times. The pH of the leachate was measured to be 4 and remained unchanged after 3 hours.

[0044] 2) Neutralization waste liquid and material washing

[0045] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 1-5 cm pieces. Collect the leachate and washing waste liquid, and gradually add sodium bicarbonate until the leachate is neutral.

[0046] 3) Crushing

[0047] After being initially crushed into small blocks, the slag was added again at a mass ratio of 1:10 to an ice slurry containing sodium bicarbonate with a pH of 8-9 and soaked for 1 day. The slag was then filtered, washed, and dried. The dried blocks were then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0048] Example 3

[0049] A process for recycling and reusing aramid spinning punching material, specifically including the following steps:

[0050] 1) Collection and soaking

[0051] The aramid spinning punching material was collected in a polytetrafluoroethylene container and then cooled and stored at a low temperature below 5°C. 6.4 kg of the cooled punching material was placed in a 1:5 ice slurry and soaked for 1 day, during which the ice slurry was replaced with fresh ice slurry several times. The pH of the leachate was measured to be 4, and the pH was measured again after 3 hours and remained unchanged.

[0052] 2) Neutralization waste liquid and material washing

[0053] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 1-5 cm pieces. Collect the leachate and washing waste liquid, and gradually add sodium carbonate until the leachate is neutral.

[0054] 3) Crushing

[0055] After being initially crushed into small blocks, the slag was added again to an ice slurry containing sodium bicarbonate at a mass ratio of 1:5 and soaked for 1 day. The slag was then filtered, washed, and dried. The dried blocks were then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0056] Example 4

[0057] A process for recycling and reusing aramid spinning punching material, specifically including the following steps:

[0058] 1) Collection and soaking

[0059] The aramid spinning punching material was collected in a polytetrafluoroethylene container and then cooled and stored at a low temperature below 5°C. 5.5 kg of the cooled punching material was placed in a 1:10 ice slurry and soaked for 1 day, during which the ice slurry was replaced with fresh ice slurry several times. The pH of the leachate was measured to be 4, and the pH was measured again after 3 hours and remained unchanged.

[0060] 2) Neutralization waste liquid and material washing

[0061] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 1-5 cm pieces. Collect the leachate and washing waste liquid, and gradually add calcium carbonate until the leachate is neutral.

[0062] 3) Crushing

[0063] After being initially crushed into small blocks, the slag was added again to a sodium bicarbonate-containing ice slurry with a pH of 8-9 at a mass ratio of 1:5 and soaked for 1 day. The slag was then filtered, washed, and dried. The dried blocks were then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0064] Example 5

[0065] A process for recycling and reusing aramid spinning punching material, specifically including the following steps:

[0066] 1) Collection and soaking

[0067] The aramid spinning feed material was collected in a polytetrafluoroethylene container and then cooled and stored at a low temperature below 5°C. 5.2 kg of the cooled feed material was placed in a 1:10 ice slurry and soaked for 1 day, during which the ice slurry was replaced with fresh ice slurry several times. The pH of the leachate was measured to be 5, and the pH was measured again after 3 hours and remained unchanged.

[0068] 2) Neutralization waste liquid and material washing

[0069] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 1-5 cm pieces. Collect the leachate and washing waste liquid, and gradually add calcium hydroxide until the leachate is neutral.

[0070] 3) Crushing

[0071] After being initially crushed into small blocks, the slag was added again to an ice slurry containing sodium bicarbonate at a mass ratio of 1:5 and soaked for 1 day. The ice slurry was neutral. The slag was then filtered, washed, and dried. The dried blocks were then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0072] Example 6

[0073] A process for recycling and reusing aramid spinning punching material, specifically including the following steps:

[0074] 1) Collection and soaking

[0075] The aramid spinning feed material was collected in a polytetrafluoroethylene container and then cooled and stored at a low temperature below 5°C. 5.2 kg of the cooled feed material was placed in a 1:5 ice slurry and soaked for 2 days, during which the ice slurry was replaced with fresh ice slurry several times. The pH of the leachate was measured to be 6, and the pH was measured again after 3 hours and remained unchanged.

[0076] 2) Neutralization waste liquid and material washing

[0077] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 1-3 cm pieces. Collect the leachate and washing waste liquid, and gradually add potassium hydroxide until the leachate is neutral.

[0078] 3) Crushing

[0079] After being initially crushed into small blocks, the slag was added again to an ice slurry containing sodium hydroxide at a mass ratio of 1:10 and soaked for 1 day. The ice slurry was neutral. The slag was then filtered, washed, and dried. The dried blocks were pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0080] Example 7

[0081] A process for recycling and reusing aramid spinning punching material, specifically including the following steps:

[0082] 1) Collection and soaking

[0083] The aramid spinning feed material was collected in a polytetrafluoroethylene container and then cooled and stored at a low temperature below 5°C. Six kilograms of the cooled feed material was placed in a 1:20 ice slurry and soaked for one day, with fresh ice slurry being replaced several times during the day. The pH of the leachate was measured to be 6, and the pH remained unchanged after 3 hours.

[0084] 2) Neutralization waste liquid and material washing

[0085] Remove the washing material from the ice slurry, wash it with cold water, dry it, and break it into 2-5 cm pieces. Collect the leachate and washing waste liquid, and gradually add calcium carbonate until the leachate is neutral.

[0086] 3) Crushing

[0087] After being initially crushed into small blocks, the slag was added again to an ice slurry containing sodium carbonate at a mass ratio of 1:20 and soaked for 1 day. The ice slurry was neutral. The slag was then filtered, washed, and dried. The dried blocks were then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0088] Comparative Example 1

[0089] Soak at room temperature:

[0090] 1) Collection and Cooling

[0091] Approximately 5.6 kg of car wash material was added to deionized water and cooled to solidify. It was then soaked in a 1:10 deionized water solution at room temperature (25°C) for one day, with the water being changed several times during this period. The pH of the leachate was measured to be 5, and after 3 hours, the pH was measured again and remained unchanged.

[0092] 2) Neutralization waste liquid and material washing

[0093] Sodium hydroxide was gradually added to the leached acidic waste liquid until the waste liquid became neutral. The soaked waste material was then broken into pieces of 1-5 cm in size and washed and dried again with cold water.

[0094] 3) Crushing

[0095] The powder was pulverized to obtain a particle size of approximately 30–80 μm.

[0096] Comparative Example 2

[0097] Neutralize by soaking in a dilute alkaline solution:

[0098] 1) Collection and neutralization

[0099] 4.5 kg of aramid spinning filler material was cooled with an appropriate amount of deionized water to rapidly solidify the filler material into block form. This block form was then soaked in a 5 wt% sodium hydroxide solution for one day, with the sodium hydroxide solution being changed several times during the soaking period.

[0100] 2) Crushing and washing

[0101] After soaking, the waste material is broken into pieces of 1-5cm in size, then washed again with cold water and dried.

[0102] 3) Crushing

[0103] The dried blocks were pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0104] Comparative Example 3

[0105] Neutralize by soaking in a carbonate solution:

[0106] 1) Collection and neutralization

[0107] Add an appropriate amount of deionized water to 4.6 kg of spinning punching material and cool it to make the punching material solidify quickly, resulting in block punching material. Soak it in a saturated sodium bicarbonate solution for 1 day, changing the sodium bicarbonate solution several times during the period.

[0108] 2) Broken

[0109] The block is initially broken into small pieces of about 1-5 cm, then washed with cold water and dried again.

[0110] 3) Crushing

[0111] The dried blocks were pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0112] Comparative Example 4

[0113] Neutralize by soaking in a concentrated alkaline solution:

[0114] 1) Collection and neutralization

[0115] The collected 6.1 kg of spinning spun yarn was cooled with an appropriate amount of deionized water to rapidly solidify the spun yarn, resulting in block-shaped spun yarn. This block-shaped spun yarn was then soaked in an excess of 32% sodium hydroxide solution for one day.

[0116] 2) Crushing and granulation

[0117] The strength of the rubber block decreased significantly and it cracked on its own. The block was removed, washed again with cold water until nearly neutral, and then dried. The dried block was then pulverized using a high-speed pulverizer to obtain powder with a particle size of approximately 50–100 μm.

[0118] Figure 2 The figure shows a comparison of the morphology of recycled aramid particles in the recycling process. As can be seen from the figure, the color of the recycled resin in Example 1 is brighter than that in Comparative Example 1 and Comparative Example 4, and is closer to that of the virgin resin.

[0119] Figure 3 This comparison shows the decrease in specific viscosity of recycled aramid resin particles during the recycling process compared to the direct alkali treatment method. The figure shows that the specific viscosity of the product from Example 1 decreased significantly compared to the direct alkali treatment. In the comparative example of alkali treatment, the viscosity of the recycled aramid resin particles decreased as the alkalinity and concentration of the alkali solution increased during the treatment process. This demonstrates that the resin particles are sensitive to alkaline substances during recycling, confirming the effectiveness of this strategy for resin recycling.

[0120] Figure 4The results show the thermogravimetric analysis curves of the recycled aramid resin particles in the recycling process. The results show that the residual carbon value of the product in Example 4 is closer to that of the virgin resin after thermal decomposition compared to Comparative Example 1 and Comparative Example 4. This indicates that the resin particles in Example 4 maintained the integrity of the chain segments during the recycling process, while in Comparative Example 1 and Comparative Example 4, the molecular chain segments were largely destroyed by hydrolysis or alkaline hydrolysis during the resin recycling process. The functional groups were broken off and removed by heat, taking away additional residual carbon, resulting in a decrease in the overall residual carbon value.

[0121] Figure 5 This is a comparison of XRD patterns of aramid resin particles recovered through recycling and reuse processes with virgin resin. The figures show that the peak positions of the recovered resin remain largely unchanged. Compared to virgin resin, the diffraction peak intensity near 20.5° decreases, reflecting the lateral packing spacing of the PPTA molecular chains. Due to the removal of sulfuric acid during the dissolution and slurry preparation processes and the subsequent washing after solidification, the lateral packing density of the PPTA molecular chains decreases, resulting in a lower regularity compared to virgin resin. The diffraction peak of the recovered resin particles near 22.8° is similar to that of the virgin resin, primarily involving van der Waals interactions between aromatic rings. This peak is also sharp, confirming crystal integrity. The diffraction peak of the resin near 28.7° is related to the periodicity of the molecular chain axis. The results show that the peak intensity and position at this point remain unchanged, indicating that the lateral regularity of the molecular chains and the high periodicity of the chemical repeating units along the chain axis are maintained during the recycling process.

[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for recycling and reusing aramid spinning punching material, characterized in that, Includes the following steps: (1) Collect the aramid spinning punching material blocks and cool them down; (2) Soak the cooled car wash material blocks in ice water / ice slurry, replacing the ice water / ice slurry during the process until the acidity of the leachate decreases to weak acidity and stabilizes, then break the car wash material blocks. (3) The crushed PPTA resin blocks are soaked in alkaline ice water / ice slurry until the pH of the leachate is close to neutral. Then, they are crushed again using a crushing device, washed, and dried to obtain recycled PPTA resin particles.

2. The process for recycling and reusing aramid spinning punching material according to claim 1, characterized in that, In step (1), the material being punched is cooled to below 5°C.

3. The process for recycling and reusing aramid spinning punching material according to claim 2, characterized in that, In step (2), the mass ratio of the flushing material block to ice water / ice slurry is 1:5~20.

4. The process for recycling and reusing aramid spinning punching material according to claim 3, characterized in that, In step (2), after the pH of the leachate is stabilized at 4-6, the rubber block of the washing car is broken up.

5. The process for recycling and reusing aramid spinning punching material according to claim 1, characterized in that, In step (2), the diameter of the crushed rubber block is 1~5 cm.

6. The process for recycling and reusing aramid spinning punching material according to claim 1, characterized in that, The leachate from step (2) is collected, and then a neutralizing agent is added to neutralize the acidity of the leachate, resulting in neutral waste liquid and sulfate.

7. The process for recycling and reusing aramid spinning punching material according to claim 5, characterized in that, The neutralizing agent is an alkali or salt that can react with sulfuric acid, wherein the alkali is any one or two or more of sodium hydroxide, potassium hydroxide, and calcium hydroxide; and the salt is any one or two or more of sodium bicarbonate, sodium carbonate, and calcium carbonate.

8. The process for recycling and reusing aramid spinning punching material according to claim 7, characterized in that, The pH of the alkaline ice water / ice slurry is 7-9.

9. The process for recycling and reusing aramid spinning punching material according to claim 8, characterized in that, In step (3), the mass ratio of the crushed car wash block to the alkaline ice water / ice slurry is 1:5~20.

10. The process for recycling and reusing aramid spinning punching material according to claim 9, characterized in that, The alkaline ice water / ice slurry is prepared by adding an alkaline reagent, which is any one or two or more of sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium bicarbonate, and sodium carbonate.

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