CN104903355A - An improved method of recovering rubber from skim natural rubber latex - Google Patents

Abstract

The present invention relates to an improved method of recovering rubber from skim natural rubber latex. The method comprises pre-treating the skim latex, concentrating the skim latex using one membrane module or two membrane modules in series with addition of potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide, optionally treating the concentrated skim latex with a tetramethylthiuramdisulphide (TMTD) and zinc oxide (ZnO) dispersion, blending the concentrated latex with fresh field latex, and centrifuging the blend to obtain a latex concentrate. The latex concentrate is further blended with a fresh latex concentrate and treated with ammonia to obtain the final latex concentrate.

Description

Improved method for recovering rubber from skimmed natural rubber latex

technical field

The invention relates to an improved method for recovering rubber from skimmed natural rubber latex. In particular, the present invention relates to an improved process for recovering rubber from skim natural rubber latex and converting said rubber into a latex concentrate using a combination of membrane filtration and centrifugation techniques.

Background technique

Skim clear natural rubber latex or skim latex is produced as a by-product in processes involving concentrated natural rubber latex by centrifugation to separate the rubber latex into a concentrate and skim latex. Skim latex typically only contains about 5% dry rubber, and it is usually recycled as skim crepe rubber.

It is well known in the art that rubber can be recovered from skim latex by coagulation using sulfuric acid. The recycled rubber is then dried outdoors before being sold as skim rubber. However, the skim rubber obtained by this coagulation method is of poor quality because it contains a high proportion of entrained non-rubber components and acid content. Skim rubber also has undesirable physical properties, including the development of a foul odor, which contributes to the low economic value of skim rubber. Furthermore, this method also produces highly acidic effluent which can cause pollution to the environment if it is not treated in an appropriate manner before being discharged into the environment.

Coagulation of the skim latex can also be performed by using proteolytic enzymes, wherein an enzymatic deproteinization of the skim latex is achieved. However, this process is uneconomical as it requires the use of large amounts of enzymes and involves deammonization and acid coagulation steps in the process.

Therefore, there is a need in the art to provide a method for recovering rubber from skim natural rubber latex to solve at least one of the above problems, or at least provide an alternative.

Contents of the invention

The above-referenced problems and others are solved and advances are made in the art by an improved process for recovering rubber from skim natural rubber latex according to the present invention. One advantage of the method according to the present invention is that by using a combination of membrane filtration and centrifugation techniques to recover rubber from skim natural rubber latex and converting said rubber into a latex concentrate, the amount of waste used for skim natural rubber latex is reduced. Latex is recycled to the acid coagulation of rubber as needed. A second advantage of the present invention is that the method produces sewage with improved quality, causing less pollution to the environment.

According to one embodiment of the present invention, the method is implemented in the following manner. The method begins by pretreating the skim latex. The pretreated skim latex is then repeatedly passed through the membrane module with the addition of potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide at intervals to obtain retentate and permeate. The retentate was blended with fresh field latex and centrifuged to obtain a latex concentrate. The latex concentrate was further blended with fresh latex concentrate and treated with ammonia to obtain the final latex concentrate.

According to some embodiments of the invention, the method further comprises treating the retentate with a dispersion of tetramethylthiuram disulfide (TMTD) and zinc oxide (ZnO) prior to the step of blending the retentate with fresh field latex. retentate.

According to another embodiment of the present invention, the method further comprises subjecting the retentate to a second stage of concentration prior to blending the retentate with fresh field latex. A second stage of concentration is performed by repeatedly passing the retentate through a second membrane module and adding additional potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide to obtain a second retentate and a second permeate. The second retentate is optionally chemically treated and controllably blended with fresh field latex. The blended second retentate was centrifuged to obtain a latex concentrate. The latex concentrate is then further controlled blended with fresh latex concentrate to obtain the final latex concentrate.

According to some embodiments of the invention, the method further comprises pretreating the retentate with potassium hydroxide or a solution comprising ammonium laurate and potassium hydroxide prior to passing the retentate through the second membrane module.

According to one embodiment of the present invention, the potassium hydroxide or the solution containing ammonium laurate and potassium hydroxide is added to the pretreated skim latex every 10 minutes to 30 minutes until about 80% by weight to 90% by weight is obtained. % permeate by weight.

According to some embodiments of the present invention, the potassium hydroxide or the solution containing ammonium laurate and potassium hydroxide is added to the pretreated skim latex every 10 minutes to 30 minutes until about 60% by weight to 70% by weight is obtained. % permeate by weight. Additional potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide was added to the retentate at intervals of 10 to 30 minutes until about 40 to 50% by weight of the second permeate was obtained.

According to some embodiments of the present invention, the solution containing ammonium laurate and potassium hydroxide comprises ammonium laurate and potassium hydroxide in a ratio of 1:1.

According to one embodiment of the present invention, the method further includes cleaning the membrane assembly by soaking the membrane assembly in 2% to 5% hydrogen peroxide; backwashing or positive flushing the membrane with 1% to 2% sodium hydroxide components; and backwash or positively flush membrane components with 1% to 2% nitric acid.

Description of drawings

The above and other advantages and features of the present invention are described in the following detailed description and illustrated in the following drawings:

Fig. 1 is a flow diagram illustrating a single-stage concentration process according to the present invention.

Figure 2 is a flow diagram illustrating a secondary concentration process according to the present invention.

detailed description

According to the present invention, there is provided a process for recovering rubber from skim natural rubber latex or skim latex by concentrating the natural rubber latex or skim latex by separating the natural rubber latex into a rubber-rich cream fraction and a skim latex. Skim latex typically contains about 5% dry rubber.

The method according to one embodiment of the invention includes the step of pretreating the skim latex.

In one embodiment of the invention, the skim latex is pretreated with ammonia and potassium hydroxide. In another embodiment, the skim latex is pretreated with ammonia and a solution comprising ammonium laurate and potassium hydroxide. In a preferred embodiment, the skim latex is pretreated with about 0.35% to 0.65% ammonia and about 0.025% to 0.10% potassium hydroxide. In another preferred embodiment, the skim latex is pretreated with about 0.35% to 0.65% ammonia and about 0.025% to 0.10% solution comprising ammonium laurate and potassium hydroxide. Preferably, the solution comprises ammonium laurate and potassium hydroxide in a 1:1 ratio.

Skim latex is pretreated by simply adding ammonia and potassium hydroxide or ammonia and a solution containing ammonium laurate and potassium hydroxide to the skim latex. The mixture is then homogenized, eg by stirring. The pretreated skim latex is then subjected to a first stage concentration process.

In the first stage concentration process, the skim latex is concentrated to about 11% to 13% dry rubber content. The first-stage concentration process is implemented by repeatedly passing the skim latex through a multi-tubular membrane module. The skim latex is passed through the multi-tubular membrane module by a pump. Examples of pumps that can be used in the present invention include, but are not limited to, diaphragm type pumps or centrifugal type pumps. For large scale membrane installations centrifugal type pumps are preferred. Multi-tubular membrane modules may be made of any suitable material. In a preferred embodiment it is made of ceramic and preferably has a pore size of about 0.05μ.

When the skim latex repeatedly passes through the multi-tubular membrane module, potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the skim latex at regular intervals. Preferably, potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the skim latex every 10 minutes to 30 minutes. In a preferred embodiment, about 0.025% to 0.10% of potassium hydroxide or about 0.025% to 0.10% of a solution comprising ammonium laurate and potassium hydroxide is added to the skim latex at each time interval. The inlet pressure of the multi-tubular membrane module was set at about 2.5 bar to 4.5 bar (2.5×10 ⁵ Pa to 4.5×10 ⁵ Pa). Preferably, the transmembrane pressure is set at about 1.5 bar to 3.0 bar (1.5×10 ⁵ Pa to 3.0×10 ⁵ Pa). The solution used in this step may be potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide without limiting it to the same solution as that used in the step of pretreating skim latex.

The first stage concentration process is continued until about 60% to 70% by weight of clarified whey is obtained. The clarified whey is removed as permeate, leaving a retentate which is concentrated skim latex.

The retentate or concentrated skim latex may be treated with additional potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide before the concentrated skim latex is subjected to a secondary concentration process. The solution used in this step may be potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide without limiting it to the same solution as that used in the step of pretreating skim latex. Preferably, about 0.025% to 0.10% of potassium hydroxide or about 0.025% to 0.10% of a solution containing ammonium laurate and potassium hydroxide is added to the concentrated skim latex to treat the skim latex.

In the second concentration process, the concentrated skim latex is further concentrated to about greater than 20% dry rubber content. The second stage concentration process is implemented by repeatedly passing the concentrated skim latex through the second multi-tubular membrane module. The second multi-tubular membrane module can be the same type of membrane used in the first stage concentration process, or it can be any type suitable for use in the process. The concentrated skim latex is passed through the second multi-tubular membrane module by a pump. Examples of pumps that can be used in the method include, but are not limited to, diaphragm-type pumps or centrifugal-type pumps. For large scale membrane installations centrifugal type pumps are preferred. Multi-tubular membrane modules may be made of any suitable material. In a preferred embodiment of the present invention, the multi-tubular membrane module is made of ceramics and has a pore size of about 0.05μ. It has a channel inner diameter of about 3.0mm to 4.0mm and an overall length of about 1.0m to 1.2m.

Preferably, the concentrated skim latex is passed through the second multi-tubular membrane module at an inlet pressure of about 2.5 bar to 4.5 bar (2.5×10 ⁵ Pa to 4.5×10 ⁵ Pa). Additional potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the concentrated skim latex at intervals to further concentrate the skim latex as it repeatedly passes through the second multi-tubular membrane module . In a preferred embodiment, potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the concentrated skim latex every 10 minutes to 30 minutes. Preferably, about 0.025% to 0.10% of potassium hydroxide or about 0.025% to 0.10% of a solution comprising ammonium laurate and potassium hydroxide is added to the skim latex at each time interval. Potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide may be used in this step without limiting it to the same solution as that used in the step of pretreating the skim latex.

The second stage concentration process is continued until a clarified second whey of about 40% to 50% by weight is obtained. The clarified second whey is removed as a second permeate, leaving a second retentate which is further concentrated skim latex.

Tetramethylthiuram disulfide (TMTD) and zinc oxide (ZnO ) dispersion processing further concentrated skim latex. Preferably, the further concentrated skim latex is treated with about 0.05% to 0.10% by weight of the TMTD/ZnO dispersion. This step is performed depending on the quality of the further concentrated skim latex obtained after the concentration process (eg, the content of volatile fatty acids in the further concentrated skim latex). Preferably, this step is carried out when the volatile fatty acid value in the further concentrated skim latex exceeds 0.10. Preferably, the processed concentrated skim latex is blended with fresh field latex in a ratio of 1 part: 9 parts.

The blended concentrated skim latex containing fresh field latex was then centrifuged to obtain a latex concentrate. The latex concentrate was blended with fresh latex concentrate at a ratio of 1:9 parts. Ammonia is then added to the blended latex concentrate to greater than 0.60% m/m to obtain the final latex concentrate. The final latex concentrate thus obtained contains more than 60% dry rubber.

In another embodiment of the present invention, the first stage concentration process and the second stage concentration process can be performed in a single step, depending on the quality of the feed used in the process.

Skim latex is similarly pretreated with ammonia and potassium hydroxide or with ammonia and a solution containing ammonium laurate and potassium hydroxide in a single stage process. In a preferred embodiment, the skim latex is pretreated with about 0.35% to 0.65% ammonia and about 0.025% to 0.10% potassium hydroxide. In another preferred embodiment, the skim latex is pretreated with about 0.35% to 0.65% ammonia and about 0.025% to 0.10% solution comprising ammonium laurate and potassium hydroxide. Preferably, the solution containing ammonium laurate and potassium hydroxide has a ratio of 1:1.

Skim latex is pretreated by simply adding ammonia and potassium hydroxide or ammonia and a solution containing ammonium laurate and potassium hydroxide to the skim latex. The mixture is then homogenized, eg by stirring. The pretreated skim latex is then subjected to a single-stage concentration process.

According to this embodiment of the present invention, a single-stage concentration process is implemented by repeatedly passing the skim latex through a multi-tubular membrane module. The skim latex is passed through the multi-tubular membrane module by a pump. Examples of pumps that can be used in the method include, but are not limited to, diaphragm-type pumps or centrifugal-type pumps. For large scale membrane installations centrifugal type pumps are preferred. Multi-tubular membrane modules may be made of any suitable material. In a preferred embodiment of the present invention, the multi-tubular membrane module is made of ceramics and has a pore size of about 0.05μ. It has a channel inner diameter of about 3.0mm to 4.0mm and an overall length of about 1.0m to 1.2m.

When the skim latex repeatedly passes through the multi-tubular membrane module, potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the skim latex. Potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide was added to the skim latex at regular intervals. Preferably, potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the skim latex every 10 minutes to 30 minutes. In a preferred embodiment, about 0.025% to 0.10% of potassium hydroxide or about 0.025% to 0.10% of a solution comprising ammonium laurate and potassium hydroxide is added to the skim latex at each time interval. The inlet pressure of the membrane was set at about 2.5 to 4.5 bar (2.5×10 ⁵ Pa to 4.5×10 ⁵ Pa). In a preferred embodiment, the transmembrane pressure is set at about 1.5 to 3.0 bar (1.5×10 ⁵ Pa to 3.0×10 ⁵ Pa) for optimal permeate flux.

The single stage concentration process is continued until about 80% to 90% by weight of clear whey is obtained. The clarified whey is removed as permeate, leaving a retentate which is concentrated skim latex.

The concentrated skim latex can optionally be treated with a TMTD/ZnO dispersion at a concentration of 30% with a ratio of 1:1. Preferably, the concentrated skim latex is treated with about 0.05% to 0.10% by weight of the TMTD/ZnO dispersion. This step is carried out depending on the quality of the concentrated skim latex obtained after the concentration process (for example, the content of volatile fatty acids in the concentrated skim latex). Preferably, this step is carried out when the volatile fatty acid value in the concentrated skim latex exceeds 0.10. The treated concentrated skim latex is then blended with fresh field latex preferably in a 1:9 parts ratio.

The blended concentrated skim latex containing fresh field latex was centrifuged to obtain a latex concentrate. The latex concentrate was then blended with fresh latex concentrate at a ratio of 1:9 parts. Ammonia is then added to greater than 0.60% m/m to obtain the final latex concentrate. The final latex concentrate thus obtained contains more than 60% dry rubber.

The above-mentioned solution of ammonium laurate and potassium hydroxide may contain any suitable amount of ammonium laurate and potassium hydroxide. In a preferred embodiment, the solution comprises ammonium laurate and potassium hydroxide in a 1:1 ratio.

In the present invention, the clarified whey produced from the skim latex concentration process can be used to recover the valuable biochemicals contained therein using suitable methods known in the art. Membranes can become fouled after use. A fouled membrane can be cleaned by soaking it in approximately 2% to 5% hydrogen peroxide and backwashed or forward flushed with approximately 1% to 2% sodium hydroxide. A fouled membrane can also be backwashed or positively flushed with nitric acid to remove inorganic fouling and regenerate the membrane for further use. Preferably, the fouled membrane is backwashed or flushed with about 1% to 2% nitric acid.

In methods according to embodiments of the present invention, the skim latex is concentrated by a membrane system before being blended with fresh field latex and re-centrifuged back into a latex concentrate. The use of membranes as a means of concentrating the skim latex eliminates the need for acid coagulation for rubber recovery from the skim latex. This also helps to improve the quality of the effluent produced by the method. A combination of chemicals can be used to clean a fouled membrane to regenerate it for subsequent concentration. The recovery of rubber and its conversion into latex concentrate is a value-added process for the rubber industry.

The use of potassium hydroxide in the present invention is advantageous because potassium hydroxide acts as a latex stabilizer and latex preservative. This also provides better resistance to agitation by any suitable mechanical means.

The following examples are provided to further illustrate and describe certain embodiments of the invention, and are not to be construed in any way as limiting the invention to the specific procedures, conditions or compositions described herein.

Example

Embodiment 1: secondary concentration process

Skim latex with a dry rubber content of 5% was screened through a 60 mesh wire screen and pretreated with 0.65% ammonia and 0.1% potassium hydroxide. The treated skim latex is then repeatedly passed through a multi-tubular membrane module. The multi-tubular membrane module used in this example has a pore diameter of about 0.05 μ, a channel inner diameter of about 3.0 mm to 4.0 mm, and a total length of 1.0 m to 1.2 m. The inlet pressure of the membrane module was set at about 3 bar (3×10 ⁵ Pa). The skim latex was concentrated by adding about 0.05% potassium hydroxide to the skim latex every 30 minutes.

This concentration step is continued until about 60% to 70% by weight of clear whey is obtained and removed as a first permeate, leaving a first retentate containing about 11% dry rubber.

The first retentate was then treated with an additional 0.1% potassium hydroxide. The treated first retentate was then repeatedly passed through the second multi-tubular membrane module at an inlet pressure of about 3 bar (3×10 ⁵ Pa). The skim latex was further concentrated by adding approximately 0.05% potassium hydroxide to the first retentate every 30 minutes. A further concentration step is performed until about 40% to 50% by weight of a clarified second whey is obtained and removed as a second permeate. A second retentate containing more than 20% dry rubber is also obtained after the second concentration step.

The second retentate was then treated with about 0.05% TMTD/ZnO (in a 1:1 ratio) dispersion (30% concentration) before blending the second retentate with fresh field latex in a 1:9 ratio. Two holdups. The blended retentate containing fresh field latex was then centrifuged using a skim screw of choice (12 gauge or 12.5 mm long) to obtain a latex concentrate. The treated latex concentrate was then further blended with fresh latex concentrate at a ratio of 1:9 parts and ammoniated to greater than 0.60% m/m ammonia to obtain the final latex concentrate.

The final latex concentrate obtained by this process is of comparable quality to ordinary fresh latex concentrate. This is a value-added process in the rubber industry, since rubber recovered from skim latex and converted into latex concentrate sells for a better price than skim latex recovered and converted into skim crepe rubber.

Embodiment 2: secondary concentration process

Skim latex with 5% dry rubber content was screened through a 60 mesh wire screen and pretreated with 0.65% ammonia and 0.1% solution containing ammonium laurate and potassium hydroxide in a 1:1 ratio . The treated skim latex is then repeatedly passed through a multi-tubular membrane module. The multi-tubular membrane module used in this example has a pore diameter of about 0.05 μ, a channel inner diameter of about 3.0 mm to 4.0 mm, and a total length of 1.0 m to 1.2 m. The inlet pressure of the membrane module was set at about 3 bar (3×10 ⁵ Pa). The skim latex was concentrated by adding approximately 0.05% of ammonium laurate and potassium hydroxide to the skim latex every 30 minutes.

This concentration step is continued until about 60% to 70% by weight of clear whey is obtained. The clarified whey was removed as the first permeate, leaving a first retentate containing about 11% dry rubber.

The first retentate was then treated with an additional 0.1% solution containing ammonium laurate and potassium hydroxide. The treated first retentate was then repeatedly passed through the second multi-tubular membrane module at an inlet pressure of about 3 bar (3×10 ⁵ Pa). The skim latex was further concentrated by adding approximately 0.05% ammonium laurate and potassium hydroxide to the first retentate every 30 minutes. A further concentration step is performed until about 40% to 50% by weight of a clarified second whey is obtained. The clarified second whey was removed as the second permeate. A second retentate containing more than 20% dry rubber is also obtained after the second concentration step.

The second retentate was then treated with about 0.05% TMTD/ZnO (in a 1:1 ratio) dispersion (30% concentration) before blending the second retentate with fresh field latex in a 1:9 ratio. Two holdups. The blended retentate containing fresh field latex was then centrifuged using a skim screw of choice (12 gauge or 12.5 mm long) to obtain a latex concentrate. The treated latex concentrate was then further blended with fresh latex concentrate at a ratio of 1:9 parts and ammoniated to greater than 0.60% m/m ammonia to obtain the final latex concentrate.

The final latex concentrate obtained by this process is of comparable quality to ordinary fresh latex concentrate.

Embodiment 3: single-stage concentration process

In this single-stage process, only one concentration step is performed on the skim latex. In addition to continuing the single concentration step in this single-stage process until about 80% to 90% by weight of clarified whey is obtained and removed as permeate, the pretreatment steps and operating conditions in this process are as The secondary process described in Example 1 and Example 2 is similar. The retentate obtained in this single stage process contains more than 20% dry rubber.

After the concentration step, the retentate was treated with about 0.05% TMTD/ZnO (1:1 ratio) dispersion (30% concentration) before blending the retentate with fresh field latex at a ratio of 1:9 The retentate obtained from the concentration step is disposed of. The blended retentate containing fresh field latex was then centrifuged using a skim screw of choice (12 gauge or 12.5 mm long) to obtain a latex concentrate. The treated latex concentrate was then further blended with fresh latex concentrate at a ratio of 1:9 parts and ammoniated to greater than 0.60% m/m ammonia to obtain the final latex concentrate.

The final latex concentrate obtained by this single stage process is of comparable quality to ordinary fresh latex concentrate and to latex concentrate obtained by the two stage process as described above.

The above is a description of what the inventors believe to be the subject matter of the invention, and it is believed, based on the above disclosure, that others can and will design alternative systems incorporating the invention.

Claims (21)

1. A method of concentrating natural rubber latex by separating natural rubber latex into rubber latex and skim latex, thereby reclaiming rubber from skim latex, said method comprising: Pretreating the skim latex; Make the pretreated skim latex repeatedly pass through the membrane module and add potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide at regular intervals to obtain retentate and permeate; blending the retentate with fresh field latex; centrifuging the blended retentate to obtain a latex concentrate; blending the latex concentrate with fresh latex concentrate; and The blended latex concentrate is treated with ammonia to obtain a final latex concentrate. 2. The method of claim 1, further comprising: The retentate was treated with tetramethylthiuram disulfide (TMTD) and zinc oxide (ZnO) dispersions prior to the step of blending the retentate with fresh field latex. 3. The method of claim 1, further comprising: Prior to the step of blending the retentate with fresh field latex, the retentate was repeatedly passed through the second membrane module with the addition of additional potassium hydroxide or ammonium laurate and potassium hydroxide containing solution to obtain a second retentate and a second permeate. 4. The method of claim 3, further comprising: The second retentate was treated with tetramethylthiuram disulfide (TMTD) and zinc oxide (ZnO) dispersion. 5. The method of claim 3, further comprising: The retentate is pretreated with potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide prior to passing the retentate through the second membrane module. 6. The method of claim 1, wherein the potassium hydroxide or a solution containing ammonium laurate and potassium hydroxide is added to the pretreated skim latex every 10 minutes to 30 minutes until About 80% to 90% by weight of the permeate is obtained. 7. The method of claim 3, wherein the potassium hydroxide or the solution containing ammonium laurate and potassium hydroxide is added to the pretreated skim latex every 10 minutes to 30 minutes until About 60% to 70% by weight of the permeate is obtained. 8. The method of claim 7, wherein the additional potassium hydroxide or solution containing ammonium laurate and potassium hydroxide is added to the retentate at intervals of 10 minutes to 30 minutes until about 40 % by weight to 50% by weight of said second permeate. 9. The method of claim 1 or 3, wherein the skim latex is pretreated with ammonia and potassium hydroxide or ammonia and a solution containing ammonium laurate and potassium hydroxide. 10. The method of claim 9, wherein the skim latex is pretreated with 0.35% to 0.65% by weight ammonia and 0.025% to 0.1% by weight potassium hydroxide. 11. The method of claim 9, wherein the skim skim is pretreated with 0.35% to 0.65% by weight of ammonia and 0.025% to 0.1% by weight of the solution containing ammonium laurate and potassium hydroxide latex. 12. The method according to claim 1 , 3, 5 or 11, wherein the ammonium laurate and potassium hydroxide containing solution comprises ammonium laurate and potassium hydroxide in a 1:1 ratio. 13. The method of claim 1, wherein the membrane module is a multi-tubular membrane. 14. The method of claim 13, wherein the membrane module has an inlet pressure in the range of 2.5×10 ⁵ Pa to 4.5×10 ⁵ Pa. 15. The method of claim 3, wherein the second membrane module is a multi-tubular membrane. 16. The method of claim 15, wherein the second membrane module has an inlet pressure in the range of 2.5×10 ⁵ Pa to 4.5×10 ⁵ Pa. 17. The method according to claim 3, wherein the amounts of the second retentate and the fresh field latex have a ratio of 1:9. 18. The method of claim 13, wherein the multi-tubular membrane module comprises a diaphragm type pump or a centrifugal type pump. 19. The method of claim 15, wherein the second multi-tubular membrane module comprises a diaphragm type pump or a centrifugal type pump. 20. The method of claim 1, further comprising: Clean the membrane module by: immersing the membrane assembly in 2% to 5% hydrogen peroxide; backwashing or positive flushing of the membrane module with 1% to 2% sodium hydroxide; and Backwash or positive flush the membrane module with 1% to 2% nitric acid to regenerate the membrane module for further use. 21. The method of claim 3, further comprising: Clean the second membrane module by: immersing the second membrane assembly in 2% to 5% hydrogen peroxide; backwashing or positive flushing of the membrane module with 1% to 2% sodium hydroxide; and Backwash or positive flush the membrane module with 1% to 2% nitric acid to regenerate the membrane module for further use.