FI127583B

FI127583B - A method for making a lignin component, a lignin component and its use and a product

Info

Publication number: FI127583B
Application number: FI20126273A
Authority: FI
Inventors: Mauno Miettinen
Original assignee: Upm Kymmene Corp
Priority date: 2012-12-05
Filing date: 2012-12-05
Publication date: 2018-09-28
Also published as: FI20126273A

Abstract

The invention relates to a method for making a lignin component from lignin material by an acid treatment, the method comprising: forming a lignin component of lignin material by treating the lignin material by means of an acid composition in at least one acid treatment stage, and the lignin component is washed and neutralized by a pH-buffer during a filtration after the acid treatment, and pH in pH-buffer is between 4 – 10. Further, the invention relates to a filtration device, corresponding lignin components, a use of the lignin component and a product.

Description

A METHOD FOR MAKING A LIGNIN COMPONENT, A LIGNIN COMPONENT AND ITS USE AND A PRODUCT

FIELD OF THE INVENTION

The invention relates to a method for manufacturing a lignin component. Further, the invention relates to a lignin component and a use of the lignin component. Further, the invention relates to a product .

BACKGROUND OF THE INVENTION

Known from publication WO 2006/031175 is a method for separation of lignin from black liquor.

OBJECTIVE OF THE INVENTION

The objective of the invention is to disclose a new method for manufacturing a lignin component. Another objective of the invention is to produce a lignin component with improved properties and a product comprising the lignin component.

SUMMARY OF THE INVENTION

The method for making a lignin component from lignin material according to the present invention is characterized by what is presented in claim 1.

The lignin component according to the present invention is characterized by what is presented in claim 15.

The use of the lignin component according to 30 the present invention is characterized by what is presented in claim 18.

The product according to the present invention is characterized by what is presented in claim

19.

BRIEF DESCRIPTION OF THE FIGURES

The accompanying figures, which are included 5 to provide a further understanding of the invention and constitutes a part of this specification, illustrate some embodiments of the invention and together with the description help to explain the principles of the invention. In the figures:

Fig. 1	is	a flow	chart	illustration of a
method according	to	one embodiment	of the present in-
vention,
Fig. 2	is	a flow	chart	illustration of a
method according	to	another	embodiment of the present
invention, and
Fig. 3	is	a device	according to one embodi-

20126273 prh 12 -02- 2018 ment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

In the method of the present invention a lignin component is made from lignin material (1) by an acid treatment. According to the invention a lignin component (3) is formed of lignin material (1) by treating the lignin material by means of an acid composition in at least one acid treatment stage (2); and the lignin component is washed and neutralized (6) by a pH-buffer during a filtration (4) after the acid treatment, and pH in pH-buffer is between 4-10.

One embodiment of the method of the present invention is shown in figure 1. Another embodiment of the method of the present invention is shown in figure 2. One embodiment of the device of the present invention is shown in figure 3.

In this context, lignin material refers any material or composition containing lignin. The lignin material may contain one or more material components.

20126273 prh 12 -02- 2018

In one embodiment suitable and desired additives can be added into the lignin material to form a desired lignin component.

In one embodiment the lignin material in5 eludes material which is selected from a group consisting of lignin from alkaline pulping process, kraft lignin, lignin from soda process, lignin coming from a process in which lignin is separated the raw material by a solution including suitable chemicals and their combinations.

In one embodiment the lignin material includes flash precipitated lignin. In one embodiment flash precipitated lignin is obtained after CO₂precipitation. Preferably, flash precipitated lignin is formed as disclosed in patent application PCT/FI2011/050896.

In one embodiment the lignin is precipitated from the black liquor by a continuous process with CO₂at 6 - 10 bar overpressure. In one embodiment the lig20 nin is separated by a flash precipitation lignin separation method, such as disclosed in patent application PCT/FI2011/050896. In one embodiment of the present invention the lignin is flash precipitated lignin. The term flash precipitated lignin should be understood in this specification as lignin that has been precipitated from black liquor in a continuous process by decreasing the pH of a black liquor flow, under the influence of an over pressure of 200 - 1000 kPa, down to the precipitation level of lignin using a carbon diox30 ide based acidifying agent, preferably carbon dioxide, and by suddenly releasing the pressure for precipitating lignin. The residence time in the above method is under 300 s. The flash precipitated lignin particles, having a particle diameter of less than 2 pm, form ag35 glomerates, which can be separated from black liquor using e.g. filtration. The flash precipitated lignin

20126273 prh 12 -02- 2018 can be purified and/or activated if needed for the further processing. The flash precipitated lignin has many advantages, e.g. activity, dispersability, solubility, drainability and preservability. In one embod5 iment of the present invention, the lignin component is a flash precipitated kraft lignin. Preferably, the flash precipitated kraft lignin is undrained. Therefore the lignin has higher activity, and the lignin can be re-dissolved. The lignin needs only a very sim10 pie re-dispersing stage when it is added e.g. into an adhesive mixture. Also control of the amount of water in the lignin based composition is easier when the redispersing is easier. Further, the lignin is easier to handle in the process because the lignin is not dusty.

Preferably, the flash precipitated kraft lignin has dry matter content of 50 - 80 %.

In one embodiment the lignin material is treated chemically and/or mechanically before the at least one acid treatment stage of the present inven20 tion. In one embodiment the lignin material is precipitated before the at least one acid treatment stage. In one embodiment the lignin material is re-slurried before the at least one acid treatment.

In this context, a lignin component means product formed from lignin material in at one or more stages. Term lignin component is already used after the first treatment stage.

In one embodiment the at least one acid treatment stage (2) is selected from a group consist30 ing of acid washing, acid hydrolysis and their combinations. The acid treatment (2) is carried at one stage or alternatively at more than one stage. In one embodiment the at least one acid treatment stage (2) is acid washing. In one embodiment the at least one acid treatment stage (2) is acid hydrolysis. In one embodiment the lignin material (1) is treated at two

20126273 prh 12 -02- 2018 acid treatment stages (2) in which one of stages is acid washing and one of stages is acid hydrolysis.

In this context, the acid washing refers to any acid washing method. In one embodiment the acid washing is performed with an acid composition containing sulphuric acid (H₂SO₄), other acid or other suitable acidifying chemical or their combination. The optimization of the process affects positively consumption of H₂SO₄ or other acid or other acidifying chemi10 cal.

In this context, the acid hydrolysis refers to any acid hydrolysis method. In one embodiment the acid hydrolysis is performed by means of H₂SO₄, or other suitable acidifying chemical, typically in the presence of water.

In one embodiment the acid composition includes H₂SO₄ which can be virgin acid or recycled acid. In one embodiment the acid composition includes acidifying chemical.

Preferably, in the acid treatment stage of the invention a suitable combination of temperature, retention time and pH level is selected. The selected combination varies based on acid washing or hydrolysis method, lignin material, acid composition and desired product.

Any acid treatment process can be used in connection with the present invention, for example acid treatment process as disclosed patent application FI20116253 or FI20125703 or other suitable acid treat30 ment method can be used.

In one embodiment a lignin component is made from lignin material (1) by a mild acid treatment so that the lignin material (1) is treated in at least one acid treatment stage (2) and the at least one acid treatment stage is optimized by means of a combination of process parameters comprising retention time, e.g.

20126273 prh 12 -02- 2018 long retention time, temperature, e.g. high temperature, and pH level, e.g. sufficient low, in order to decrease ash and/or carbohydrates in the lignin component, and preferably in order to remove undesired sub5 stance from the lignin component and to purify the lignin component. In one embodiment the lignin component is formed as disclosed in patent application FI 20116253.

In one embodiment the method comprising: op10 timizing process conditions in the acid treatment stage so that high temperature, long retention time and low pH level are used during the acid treatment.

Preferably, long retention time is used at the acid treatment stage, in at least one acid treat15 ment stage. In this context, retention time means time of the acid treatment stage. The retention time does not include a filtration time.

In one embodiment the retention time which is over 6 hour is used during the acid treatment. Prefer20 ably, a lignin component is made from lignin material by an acid treatment, the method comprising: forming a lignin component of lignin material by treating the lignin material in at least one acid treatment stage; and optimizing process conditions by means of a combi25 nation of process parameters comprising retention time, temperature and pH level at the acid treatment stage so that the retention time is over 6 hours during at least one acid treatment stage.

In one embodiment the retention time which is over 8 hour is used during the acid treatment. In one embodiment the retention time which is over 10 hour is used during the acid treatment. In one embodiment the retention time which is over 16 hour is used during the acid treatment.

In one embodiment the temperature which is over 70 °C is used during the acid treatment. In one

20126273 prh 12 -02- 2018 embodiment the temperature is over 72 °C, more preferable over 73 °C, and most preferable over 75 °C.

In one embodiment the pH level which is between 0.5 - 4 is used during the acid treatment. In a preferred embodiment pH level is sufficient low during the treatment stage. In one embodiment the pH level is under 3.5, preferable between 2-3. In one embodiment the pH level is under 2.0, preferably between 0.5 1.5. In one embodiment the pH level which is between 2

- 4 can be used.

In one embodiment the method comprises a pretreatment step before the at least one acid treatment stage. In one embodiment the lignin material is reslurried in the pre-treatment step. In a preferred em15 bodiment the pre-treatment step is a softening step of lignin in which the lignin is softened and structure of the lignin is modified.

It is important for the invention that long retention time is used at least in one acid treatment stage. Alternatively, the long retention time can be used in more than one stage. The long retention time can be used at the acid treatment stage, e.g. in the acid washing and/or in the acid hydrolysis, and/or in the pre-treatment step.

Increasing retention time and/or temperature dry solid content and filterability may be improved. Improved dry solid content of filter cake leads to lower energy consumption in drying and to lower consumption of washing liquid in washing to reach good purify.

In one embodiment pH in pH-buffer is between 5-9. In one embodiment pH in pH-buffer is between 6

8. In one embodiment pH in pH-buffer is over 4, preferably over 5, and more preferable over 6. In one embodiment pH in pH-buffer is below 10, preferably below 9, and more preferable below 8. Highly alkaline washing liquid, in which pH is higher than 10, increases dissolution of lignin rapidly.

In one embodiment pH-buffer is in the form of solution.

20126273 prh 12 -02- 2018

The pH-buffer may include one or more than one component. Preferably, the pH-buffer contains at least one buffer agent. In one embodiment the pHbuffer includes buffer agent selected form a group consisting of citrate, acetate, carbonate and their combinations. In one embodiment the pH-buffer includes alkaline based compound, e.g. NaOH. In one embodiment the alkaline based compound is used to adjust pH level in the pH-buffer. In one embodiment the pH-buffer includes citrate as a buffer agent. In one embodiment the pH-buffer includes citrate and alkaline based compounds and water, and pH of the pH-buffer is between 5 - 7. Alternatively, the pH-buffer can include any suitable buffer agent. In one embodiment the pH-buffer includes water. Composition of the pH-buffer can be optimized by taken into account the requirements of processes and final products.

Preferably, the method of the invention comprises the filtrating (4) of the lignin component after the acid treatment. In one embodiment the formed lignin component (3) is filtrated at the filtration stage (4) after at least the latest acid treatment stage (2).

In this context, the filtration refers to any filtration method which can be used in the filtration of the lignin. Preferably, in the filtration the lignin component is filtrated, washed and pressed and optionally air-dried. The filtration can be performed by any suitable filtration device. In one embodiment the formed lignin component is filtrated by pressure filtration or vacuum filtration. In one embodiment pressure is between 10 - 20 bar, preferably 13 - 17 bar, preferably 13

20126273 prh 12 -02- 2018 bar and more preferable about 15 bar in the pressure filtration.

The filtration comprises a filtrating step, containing feeding of the lignin component, for form5 ing a filter cake and washing step, such as a cake washing step, for washing the filter cake in order to decrease ash content in the lignin product. Further, the filtration may comprise a pre-pressing step before the washing step and a final pressing step after the washing step.

Preferably, the lignin component is neutralized during the filtration, preferably in connection with the washing step, such as cake washing step. Preferably the washing of the lignin component is made by means of the pH-buffer. Simultaneously, the lignin component is neutralized. The pH-buffer is used instead of clean water when washing the filter cake.

In the present invention the filtration device (10) comprises a lignin feeding equipment for feeding the lignin component (7) from an acid treatment stage into the filtration device, and a filtrating step for forming a cake of the lignin component and a washing step for washing the cake, and a pHbuffer feeding equipment (9) for feeding the pH-buffer (8) into the washing step. In the washing step the lignin component is washed and neutralized by the pHbuffer. Alternatively, the filtration device may comprise a pre-pressing step between the filtration step and the washing step and/or a final pressing step af30 ter the washing step. The pH-buffer feeding equipment (9) may contain one or more than one device selected from the group consisting of tank, pipe, pipeline, tube, pump and their combination or the like to feed the pH-buffer into the washing step.

In one embodiment the filtration device (10) comprises at least one feeding tank from which pH10

20126273 prh 12 -02- 2018 buffer or component of the pH-buffer is fed into the washing step, into the pH-buffer feeding equipment or into a mixing device. In one embodiment the pH-buffer is fed from the feeding tank into the washing step by means of the pH-buffer feeding equipment. In one embodiment the pH-buffer feeding equipment contain at least one feeding tank. In one embodiment the pHbuffer is fed from the feeding tank into the washing step .

In one embodiment the filtration device (10) comprises a mixing device (11) . In one embodiment the mixing device contains at least one mixing tank or at least one mixer, e.g. static mixer, in a container or a pipeline in order to form the pH-buffer. The pH15 buffer may be formed in the mixing device, e.g. in the mixing tank, by combining components of the pH-buffer together and/or by mixing. The pH-buffer is fed from the mixing device into the washing step by means of the pH-buffer feeding equipment or via the pH-buffer feeding equipment. Alternatively, the forming or mixing of the pH-buffer may be made in the pH-buffer feeding equipment, such as in the pipeline. In one embodiment the components of the pH-buffer is fed from the tanks into the feeding equipment for combining the components in the feeding equipment. In one embodiment the pH-buffer feeding equipment comprises the mixing device, e.g. static mixer in the pipeline.

In one embodiment the filtration device (10) comprises an adjustment device to adjust pH of the pH30 buffer between 4 to 10, preferably before the washing step. In one embodiment pH of pH-buffer is analyzed by an analyzing device. In one embodiment the filtration device (10) comprises a controlling means to determine pH of the pH-buffer and/or adjust pH of the pH-buffer between 4 to 10, preferably before the washing step. In one embodiment the controlling means comprises at

20126273 prh 12 -02- 2018 least one analyzing device. In one embodiment the controlling means comprises at least one adjustment device. In one embodiment the controlling means comprises at least one analyzing device and at least one ad5 justment device. The controlling means, adjustment device or analyzing device may be arranged in connection with the pH-buffer feeding equipment or mixing device. Alternatively, the controlling means, adjustment device or analyzing device may be arranged before the pH-buffer feeding equipment. In one embodiment the adjustment device contain means for adding pH-buffer into the washing step and/or means for adding buffer agent into the pH-buffer. In one embodiment the adjustment device contain at least one adjustable valve for adjusting the feed of the pH-buffer into the washing step. In one embodiment the pH-buffer feeding equipment contain at least one adjustable valve for adjusting the feed of the pH-buffer into the washing step wherein the adjustable valve can be adjusted e.g.

by means of controlling means or manually.

In one embodiment the forming of the pHbuffer is made as a batch process. In one embodiment the forming of the pH-buffer is made as a continuous process .

In one embodiment the filtration device comprises feeding tanks, a mixing device containing a mixing tank and a static mixer, and pH-buffer feeding equipment containing a pipeline and pump, and components of the pH-buffer from the feeding tanks and wa30 ter are fed into the mixing tank in which the batch of the pH-buffer is formed by mixing with the static mixer, and the pH-buffer is fed from the mixing device into the washing step by means of the pH-buffer feeding equipment.

In one embodiment the filtration device comprises feeding tanks, pH-buffer feeding equipment con12

20126273 prh 12 -02- 2018 taining a pipeline and pump, and a mixing device containing a static mixer in connection with the pHbuffer feeding equipment, and components of the pHbuffer from the feeding tanks and water are fed into the pipeline of the pH-buffer feeding equipment in which the pH-buffer is formed by mixing with the static mixer, and the pH-buffer is supplied into the washing step by the pump. Alternatively, components of the pH-buffer and water are not mixed in the pipeline when the pH-buffer is formed.

In one embodiment the pH-buffer is fed straightly, e.g. a feeding tank, into the washing step by means of the pH-buffer feeding equipment containing pipeline and pump.

In one embodiment temperature is over 50 °C during the filtration (4).

Preferably improved filterability, especially better filtration rate, achieved by means of the optimization leads to smaller pressure requirement in the til20 tration and to shorter filtration time. Then cheaper filters, e.g. based on size and type of device, may be used.

Preferably, pH of the lignin component is between 4-8 after the filtration (4), in one embodi25 ment between 5-7. In one embodiment pH of the lignin component is over 5, in one embodiment over 6. In one embodiment pH of the lignin component is below 8, in one embodiment below 7. In a preferred embodiment pH of the lignin component is about 7.

In one embodiment the lignin component is dried after the filtration.

Further, the invention relates the lignin component which has specific properties, such as high particle size. Preferably, the lignin component has specific surface area between 0.1 - 1.0 m²/g, preferably between 0.2 - 0.7 m²/g, and more preferable be13

20126273 prh 12 -02- 2018 tween 0.3 - 0.6 m²/g. In the tests it is discovered that a particle size correlates with a specific surface area. Preferably, the lignin component has particle size which is bigger than in typical lignin prod5 ucts.

In one embodiment the lignin component is dried and/or grinded after the filtration. In one embodiment the lignin component which is dried and grinded into fine particles has bulk density between

200 - 800 g/cm³, preferably between 300 - 700 g/cm³, more preferable between 400 - 600 g/cm³, and in one embodiment about 500 g/cm³. In one embodiment the bulk density is determined so that the lignin component is dried and grinded into fine particles, and after that the grinded lignin component is put into flexible intermediate bulk container, from which a sample is taken, and the bulk density of the lignin component is measured from the sample. Preferably, the bulk density of the lignin component of the present invention is bigger than in typical lignin products known in the art.

Further, the invention relates the lignin component which is formed from lignin material by an acid treatment, wherein a lignin component is formed of lignin material so that the lignin material is treated by means of an acid composition in at least one acid treatment stage; and the lignin component is washed and neutralized by a pH-buffer during a filtration after the acid treatment, and pH in pH-buffer is between 4-10.

Preferably ash content of the lignin component is low.

Further, the invention relates a use of the lignin component such as defined above or obtainable by the method of the invention, wherein the lignin component is used as component in manufacturing a fi14

20126273 prh 12 -02- 2018 nai product selected from a group consisting of activated carbon, carbon fiber, lignin composite, binder material, phenolic component, dispersion agent and their combinations.

Further, the invention relates a product which includes the lignin component obtainable by the method of the invention. In one embodiment, the product is selected from a group consisting of activated carbon, carbon fiber, lignin composite, e.g. lignin10 plastic composite or lignin-fiber composite, binder material, phenolic component, dispersion agent and their combinations.

The invention is specially based on improving properties of the lignin component. When the lignin ma15 terial is acid treated at one or more acid treatment stage by optimizing retention time, temperature and pH level, then the properties, e.g. purity, dry solids content, filterability, amounts of carbohydrates and ash, of the lignin component can be improved. Further, odour in the lignin component can be decreased. Further, when the lignin component is neutralized then the neutral lignin component can be achieved. Then it is provided the lignin component which is suitable to use in typical and special applications.

The method according to the present invention provides the neutral lignin component with good quality, such as purify and dry solid content. When improving the purify and increasing dry solids content of the lignin component so then it may be provided better properties of the lignin product and the final product. The filterability of the lignin component and the operating costs at following process stages, e.g. in drying, are improved.

It is important that the neutral lignin compo35 nent with purify properties is achieved. The neutral lignin component is non-corrosive. Then additional pro15

20126273 prh 12 -02- 2018 cess stages are not needed to neutralize lignin, when clean water is replaced by pH-buffer during the washing. Neutralization of the lignin product in additional process stage is extremely difficult since after the sepa5 rate neutralization stage a dewatering of the lignin product is difficult to make. The production of neutral lignin is necessity for most applications. Further, even burning of the lignin component benefits from noncorrosive nature of this biofuel. Non-corrosive lignin component can be fed in application process without need for stainless/acid-proof steel as material in feeding systems. Also, standard material can be used in storage silos. Further, neutral lignin is less harmful to health.

If lignin product has pH of 2.5, so an additional process stage is needed to neutralize lignin product when close to neutral lignin is required in downstream processing or in application. Separate neutralization stage would bring significant additional cost to process, since filtering of close to neutral lignin slurry is extremely slow by using standard methods. Clearly lower dry solids content of filter cake obtained after standard neutralization stage has biggest effect on raised operating costs. Thanks to the embodi25 ments of the invention the neutral lignin product can be formed without separate neutralization stages.

The present invention provides an industrially applicable, simple and affordable way of making the lignin component from the lignin material. The method according to the present invention is easy and simple to realize as a production process. The method according to the present invention is suitable for use in the manufacture of the different lignin components from different lignin materials.

EXAMPLES

The invention is described in more detail by the following examples with reference to accompanying figures 1-3.

Example 1

In this example and in figure 1, a lignin component (3) is formed by an acid treatment.

A starting lignin material (1), which is flash precipitated lignin, is treated by one acid treatment stage (2) which is an acid washing stage. Process conditions are following: temperature is about 70 °C, retention time over 6 hour and pH level is about 3. The acid washing is performed with H₂SO₄.

The lignin component (3) is filtrated after the acid washing (2) by pressure filtration (4) . Temperature is over 50 °C during the filtration. During the filtration (4), the washing and neutralization (6) of the lignin component is made by pH-buffer solution (8) containing citrate, acetate and/or carbonate as a buffer agent. pH of the pH-buffer solution is about 5

- 7.

The neutral lignin component is achieved. The lignin component has specific surface area between 0.1

- 1.0 m² / g.

20126273 prh 12 -02- 2018

Example 2

In this example and in figure 2, a lignin component (3) is formed by an acid treatment.

A starting lignin material (1), which is flash precipitated lignin, is treated firstly at a pre-treatment stage 5 in which a re-slurry step and filtration are made, and then at one acid treatment stage (2) which is an acid washing stage. Process conditions are following: temperature is about 70 °C, re17

20126273 prh 12 -02- 2018 tention time over 6 hour and pH level is about 3. The acid washing is performed with H₂SO₄.

The lignin component (3) is filtrated after the acid washing (2) by pressure filtration (4) . Tem5 perature is over 50 °C during the filtration. During the filtration (4), the washing and neutralization (6) of the lignin component is made by pH-buffer solution (8) containing citrate, acetate and/or carbonate as a buffer agent. pH of the pH-buffer solution is about 6

- 7 .

The neutral lignin component is achieved. The lignin component has specific surface area between 0.2

- 0.7 m² / g.

Example 3

In this example and in figure 3, a lignin component (7) formed by an acid treatment is filtrated by pressure filtration (4). Temperature is over 50 °C during the filtration. During the filtration (4), the washing and neutralization (6) of the lignin component is made by pH-buffer solution containing citrate as a buffer agent. pH of the pH-buffer solution is about 6

- 7.

The filtration, washing and neutralization is carried out in a filtration device (10) . The filtration device (10) comprises a lignin feeding equipment for feeding the lignin component into the device, a filtrating step for forming a cake of the lignin component, a washing step for washing the cake and a fi30 nal pressing step for pressing. Alternatively, the filtration device may comprise a pre-pressing step between the filtration step and the washing step. A lignin component product (3) is formed during the filtration .

The pH-buffer solution is formed from buffer agent (12a) containing citrate agent, NaOH (12b) and

20126273 prh 12 -02- 2018 water (13) by mixing in a mixing device (11) comprising a mixing tank or a mixer in a container or a pipeline. The pH-buffer solution (8) is fed by pH-buffer feeding equipment (9) containing a feeding pipeline and a pump into a washing step of the filtration device (10) for washing and neutralizing a cake of the lignin component (7). Alternatively, the mixing of the pH-buffer solution may be made in the feeding equipment, such as in the pipeline.

The lignin component (3) may be dried and grinded.

Example 4

In this example, pH of the lignin component 15 product is determined after the filtration. The pH is measured from the lignin components of the present invention and reference samples.

The lignin components of the present invention have been formed by means of examples 1 and 3.

During the filtration the lignin products washed by the pH-buffer in which pH was 6. The pH-buffer contained citrate agent (2.1 g/1 citric acid), NaOH (pH 6) and water.

The reference samples have been formed by similar means than trial points. During the filtration the lignin products were washed by clean water.

In the filtration feeding, compression and cake washing times were similar when comparing water and the pH-buffer in cake washing. pH of lignin based feed was about 2.5 before the filtration. Finally, a filter cake formed in the filtration was suspended in water (ds 25 %) , mixed for 1 h at 60 °C, cooled to 25 °C and pH was measured.

Results are described in table 1.

Table 1

Lignin s amp1e	wet cake, kg	dry matter, o. o	water/ buffer	water/ buffer, used m3/t lignin	pH of lignin product
A	3.5	69.9	water	1.7	3.36
A	3.2	71.5	water	2.7	3.36
A	3.4	71.7	buffer	2.5	3.73
B	2.7	79.7	water	2.3	3.51
B	2.6	75.5	buffer	2.6	4.16

20126273 prh 12 -02- 2018

It is discovered that pH of the lignin compo5 nent can be increased by means of the method according to the present invention in comparison with reference samples .

Even when the pH of the pH-buffer was only 6, so lower than pH of clean water, the pH in the final lignin component was higher when the pH-buffer was used. This shows functionality of the invention. Ash and dry solids content of filter cake, time needed for cake washing and time needed for final pressing were similar to washing with clean water.

In these tests it was discovered that it may be produced the neutral lignin component with good properties, such as purify. It was discovered that dry solids content of the final lignin component cake and filterability and filtration rate time needed were in good level.

Further, it was discovered that lignin structure in the cake of the lignin component was in the form of big-single particles. This explains good til25 terability and high dry solids content.

The method according to the present invention is suitable in different embodiments to be used for making the most different kinds of lignin components from different lignin materials. The lignin component according to the present invention is suitable in different embodiments to be used in different final products .

	The invention is	not	limited	merely to	the
example	referred to above;	instead	many	variations	are
10 possible fined by	within the scope the claims.	of	the	inventive idea	de-

20126273 prh 12 -02- 2018

Claims

A process for the preparation of a lignin component from a lignin material by acid treatment,

5 which method comprises:

forming a lignin component from the lignin material by treating the lignin material with an acid composition in at least one acid treatment step; and

The 10-lignin component is washed and neutralized with pH buffer during filtration after acid treatment and the pH in the pH buffer is between 4-10.

The method of claim 1, wherein the at least one acid treatment step is selected from the group consisting of acid washing, acid hydrolysis and combinations thereof.

The process of claim 1 or 2, wherein the acid composition contains H ₂ SO ₄ .

20

The process of any one of claims 1 to 3, wherein the acid composition comprises an acidifying chemical.

The method of any one of claims 1 to 4, wherein the pH is in the pH buffer in the range

25 5-9.

The process according to any one of claims 1 to 5, wherein the pH is in the pH buffer between 6-8.

The method of any one of claims 1 to 6, wherein the pH buffer comprises a buffer selected from the group consisting of citrate, acetate, carbonate, and combinations thereof.

The process of any one of claims 1-7 35, wherein the process comprises: optimizing process conditions in the acid treatment step

20126273 prh 12 -02-2018 with high temperature, long retention time, and low pH during acid treatment.

The process according to any one of claims 1 to 8, wherein a retention time of more than 6 hours is used during acid treatment.

The process of any one of claims 1 to 9, wherein a retention time of more than 10 hours is used during acid treatment.

A process according to any one of claims 1 to 10, wherein a temperature greater than 70 ° C is used during the acid treatment.

A process according to any one of claims 1 to 11, wherein a pH of between 0.5 and 4 is used during acid treatment.

The method of any one of claims 1 to 12, wherein the lignin material comprises a material selected from the group consisting of lignin from an alkaline pulping process, kraft lignin, lignin from a soda process, and lignin from a process wherein the lignin is separated from the raw material by a solution, containing a suitable chemical, and combinations thereof.

The method of any one of claims 1 to 13, wherein the lignin material comprises flash-precipitated lignin.

A lignin component formed from a lignin material by acid treatment, wherein:

the lignin component is formed from the lignin material so that the lignin material is treated with the acid composition in at least one acid treatment step; and

the lignin component has been washed and neutralized with pH buffer during filtration after acid treatment and the pH in the pH buffer is between 4 and 10.

The lignin component according to claim 15, wherein the lignin component has a specific surface area between 0.1 and 1.0 m ² / g.

The lignin component according to claim 15 or 16, wherein the lignin component which has been dried and ground has a bulk density of between 200 and 800 g / cm ³ .

The use of a lignin component obtained by a process according to any one of claims 1 to 14, wherein the lignin component is used as a component in the preparation of a final product selected from the group consisting of activated carbon, carbon fiber, lignin composite, binder material, phenolic compound.

A product containing a lignin component obtained by the process of any one of claims 1-14.

The product of claim 19, wherein the product is selected from the group consisting of activated carbon, carbon fiber, lignin composite, binder material, phenolic component, dispersant and combinations thereof.