A bio-based binder and electrode paste and methods of making the same

Abstract

The present application belongs to the technical field of electrode paste. The present application provides a bio-based binder. The present application also provides a preparation method of the bio-based binder. The present application further provides an electrode paste based on the bio-based binder, which comprises 80-90 parts by mass of aggregate, 10-20 parts by mass of the bio-based binder, and 0.7-1.2 parts by mass of attapulgite. The bio-based binder comprises alcohol with a purity of 55-65%, vegetable pitch, syrup, and starch, and the mass ratio of the alcohol, the vegetable pitch, the syrup, and the starch is (20-25):(150-170):(70-85):(90-110). The present application also provides a preparation method of the electrode paste based on the bio-based binder. The prepared binder is environmentally friendly and has good uniformity. Meanwhile, the cold ramming paste prepared according to the preparation method of the cold ramming paste has high mechanical strength and low porosity.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrode paste, and particularly relates to a bio-based binder and an electrode paste and a preparation method thereof. BACKGROUND

[0002] Cold ramming paste is an electrode paste that can be constructed at room temperature, and is widely used in industrial kilns such as aluminum electrolysis cells, iron smelting furnaces, smelting furnaces, calcium carbide furnaces, etc. At present, the binders of cold ramming paste are mainly bitumen, tar and anthracene oil. These binders are mainly extracted from natural minerals such as petroleum and coal. Although these binders have been purified by chemical industry, harmful organic molecules are still difficult to completely remove. For example, polycyclic aromatic hydrocarbons (PAH) exist in bitumen, and PAH has strong carcinogenicity. The electrode paste made of these binders will release a large amount of toxic and harmful gases during kneading and subsequent high-temperature baking, which will harm the environment and people's health.

[0003] At present, plant bitumen, syrup and gelatinized starch can be used as binders for electrode paste, but there are certain technical obstacles in using the three as electrode paste binders. First, the flowability of plant bitumen is poor, and kneading needs to be carried out at a relatively high temperature, and the uniformity of the electrode paste after kneading is poor. Gelatinized starch is a solid powder, and plant bitumen and syrup as binders themselves have relatively high viscosity. When the three are mixed together, the single component is easy to clump, resulting in uneven distribution of the three components of the binder. The viscosity of starch, including gelatinized starch, is relatively low, and the addition of starch to the binder will easily cause poor mechanical strength of the electrode paste under the condition of uneven mixing, which cannot meet the use requirements. Secondly, although the three have viscosity, the difference in viscosity is relatively large, and the viscosity is also related to temperature. The proportion, temperature, etc. of the three ultimately affect the uniformity and tightness of the electrode paste during kneading and molding. If the tightness of the electrode paste after kneading and molding is not enough, the mechanical strength of the electrode paste obtained after subsequent high-temperature baking will be low. SUMMARY

[0004] Therefore, it is necessary to provide an environmentally friendly and healthy bio-based binder.

[0005] It is also necessary to provide an electrode paste based on the bio-based binder, which has high mechanical hardness and low porosity after baking.

[0006] It is also necessary to provide a preparation method of an electrode paste based on the bio-based binder, which has high mechanical hardness and low porosity after baking.

[0007] A bio-based binder comprises alcohol with a purity of 55% to 65%, plant bitumen, syrup and starch, and the mass ratio of alcohol, plant bitumen, syrup and starch is (20-25):(150-170):(70-85):(90-110).

[0008] A preparation method of a bio-based binder comprises the following steps:

[0009] Step one: add alcohol with a purity of 55% to 65%, vegetable pitch, sugar syrup, and starch into a stirring container, and mix them according to a mass ratio of (20-25):(150-170):(70-85):(90-110);

[0010] Step two: stir the alcohol and the starch at a speed of 40-60 r / min for 2-3 min at an ambient temperature of 20-30 degrees Celsius;

[0011] Step three: continue to add the sugar syrup and stir at a speed of 80-100 r / min for 5-8 min at an ambient temperature of 40-50 degrees Celsius;

[0012] Step four: continue to add the vegetable pitch and stir at a speed of 40-70 r / min for 10-15 min at an ambient temperature of 50-55 degrees Celsius to obtain the bio-based binder.

[0013] An electrode paste based on a bio-based binder comprises 80-90 parts by mass of aggregates, 10-20 parts by mass of the bio-based binder, and 0.7-1.2 parts by mass of attapulgite, wherein the bio-based binder comprises alcohol with a purity of 55% to 65%, vegetable pitch, sugar syrup, and starch, and the mass ratio of the alcohol, the vegetable pitch, the sugar syrup, and the starch is (20-25):(150-170):(70-85):(90-110).

[0014] A preparation method of an electrode paste based on a bio-based binder comprises the following steps:

[0015] Step one: add alcohol with a purity of 55% to 65%, vegetable pitch, sugar syrup, and starch into a stirring container, and mix them according to a mass ratio of (20-25):(150-170):(70-85):(90-110);

[0016] Step two: stir the alcohol and the starch at a speed of 40-60 r / min for 2-3 min at an ambient temperature of 20-30 degrees Celsius;

[0017] Step three: continue to add the sugar syrup and stir at a speed of 80-100 r / min for 5-8 min at an ambient temperature of 40-50 degrees Celsius;

[0018] Step four: continue to add the vegetable pitch and stir at a speed of 40-70 r / min for 10-15 min at an ambient temperature of 50-55 degrees Celsius to obtain the bio-based binder.

[0019] Step five: mixing the bio-based binder, aggregate and attapulgite clay for kneading and forming, wherein the mass ratio of the aggregate, bio-based binder and attapulgite clay is (80-90):(10-20):(0.7-1.2), the kneading temperature is 55-75 degrees Celsius, and the time is 50-60 minutes.

[0020] Beneficial effects: the bio-based binder of the present application is entirely composed of plant components and will not produce toxic and harmful gases at high temperatures. At the same time, the present application utilizes the physicochemical properties between different components of the binder to prepare a binder with uniform components, and the prepared environment-friendly binder has good uniformity, and the electrode paste prepared according to the electrode paste preparation method of the present application has high mechanical strength and low porosity. The detailed effects of the present application will be illustrated in combination with the following examples. DETAILED DESCRIPTION

[0021] The specific embodiments of the present application are described in detail below, but it should be pointed out that the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0022] Except for the example part, any specific numerical value (including the end points of the numerical range) disclosed herein is not limited to the exact value of the numerical value, but should be understood to also encompass values close to the exact value, for example all possible numerical values within the range of ±10% of the exact value. And for the disclosed numerical range, the end point values between the end point values, the end point values and the specific point values within the range, and the specific point values between each other can be combined to obtain one or more new numerical ranges, which should also be considered as specifically disclosed herein.

[0023] Unless otherwise specified, the terms used herein have the same meaning as generally understood by those skilled in the art, and if the terms are defined herein and are different from the generally understood meaning, the definition herein shall prevail. As "alcohol" herein is a mixture of ethanol and water, and does not specifically refer to ethanol.

[0024] The materials used in the present application are provided by Eken Carbon (China) Co., Ltd.

[0025] Example one

[0026] A bio-based binder includes alcohol with a purity of 55%-65%, plant pitch, syrup, starch, and the mass ratio of alcohol, plant pitch, syrup and starch is (20-25):(150-170):(70-85):(90-110).

[0027] The alcohol with purity of 55% to 65% refers to the volume percentage of ethanol in the alcohol being 55% to 65%.

[0028] Embodiment Two

[0029] The preparation method of the bio-based binder comprises the following steps:

[0030] Step One: add alcohol with purity of 55% to 65%, vegetable pitch, sugar syrup, and starch into a stirring container, and mix them according to the mass ratio of (20-25):(150-170):(70-85):(90-110);

[0031] Step Two: stir the alcohol and the starch at a speed of 40-60 r / min for 2-3 min at an ambient temperature of 20-30 degrees Celsius;

[0032] Step Three: continue to add the sugar syrup and stir at a speed of 80-100 r / min for 5-8 min at an ambient temperature of 40-50 degrees Celsius;

[0033] Step Four: continue to add the vegetable pitch and stir at a speed of 40-70 r / min for 10-15 min at an ambient temperature of 50-55 degrees Celsius to obtain the bio-based binder.

[0034] Embodiment Three

[0035] The electrode paste based on the bio-based binder comprises 80-90 parts by mass of aggregate, 10-20 parts by mass of bio-based binder, and 0.7-1.2 parts by mass of attapulgite, wherein the bio-based binder comprises alcohol with purity of 55% to 65%, vegetable pitch, sugar syrup, and starch, and the mass ratio of the alcohol, the vegetable pitch, the sugar syrup, and the starch is (20-25):(150-170):(70-85):(90-110).

[0036] The alcohol with purity of 55% to 65% refers to the volume percentage of ethanol in the alcohol being 55% to 65%.

[0037] Embodiment Four

[0038] The preparation method of the electrode paste based on the bio-based binder comprises the following steps:

[0039] Step One: add alcohol with purity of 55% to 65%, vegetable pitch, sugar syrup, and starch into a stirring container, and mix them according to the mass ratio of (20-25):(150-170):(70-85):(90-110);

[0040] Step two: Stir the alcohol and starch, the speed is 40-60 r / min, the time is 2-3 minutes, and the ambient temperature is 20-30 degrees Celsius;

[0041] At a lower temperature, the viscosity of the starch is smaller, and after the alcohol and starch are mixed, the surface of the starch is wrapped by the alcohol. The alcohol contains 35-45% water, which helps to disperse the starch. Through low-speed stirring, the alcohol will completely penetrate into the starch. After mixing, the starch is loose and sandy. At the same time, at a lower temperature, the alcohol is not easy to evaporate, which is conducive to the subsequent steps.

[0042] Step three: Continue to add syrup and stir, the speed is 80-100 r / min, the time is 5-8 minutes, and the ambient temperature is 40-50 degrees Celsius;

[0043] Starch is a non-polar molecule, while sucrose and water in syrup are polar molecules. When mixed together, they tend to clump separately rather than mix evenly. In step two, the alcohol coats the surface of the starch, and the water and ethanol in the alcohol are polar molecules. Therefore, the starch is more easily dispersed with the syrup. At the same time, the viscosity of the syrup decreases at a temperature range of 40-50 degrees Celsius compared to room temperature. Therefore, after 5-8 minutes of stirring, the starch and syrup can be mixed evenly.

[0044] Step four: Continue to add vegetable pitch and stir, the speed is 40-70 r / min, the time is 10-15 minutes, the ambient temperature is 50-55 degrees Celsius, and the bio-based adhesive is obtained;

[0045] Vegetable pitch has complex components and high viscosity, and poor flowability. The viscosity of the syrup is also relatively large. If vegetable pitch is directly mixed into the mixture of starch and syrup, it is difficult to mix evenly. After the syrup is mixed with the starch, the viscosity of the mixture decreases significantly due to the small viscosity of the starch and the addition of alcohol with small viscosity. At a higher temperature, the viscosity of the vegetable pitch decreases, and at this temperature, the starch has not been gelatinized and has relatively low viscosity. Therefore, the vegetable pitch can be well mixed with the mixture of starch and syrup. At the same time, as the stirring proceeds, most of the alcohol will gradually evaporate from the mixture, and a small amount of alcohol remains in the bio-based adhesive, and the physical properties of the starch have not changed significantly, and the overall viscosity of the bio-based adhesive has not reached the expected level.

[0046] Step five: Mix the bio-based adhesive, aggregate, and attapulgite to form a kneaded product, wherein the mass ratio of the aggregate, bio-based adhesive, and attapulgite is (80-90):(10-20):(0.7-1.2), the kneading temperature is 55-75 degrees Celsius, and the time is 50-60 minutes.

[0047] After baking according to the method stipulated in YS / T63.1-2019, the electrode paste can be formed at normal temperature.

[0048] In a preferred embodiment, the aggregate of the present application is selected from one or more of carbonaceous particles of electrically calcined anthracite, graphite, petroleum coke, pitch coke and metallurgical coke.

[0049] In a preferred embodiment, the mass ratio of the aggregate with particle size of 4-12mm, 2-4mm and 0-2mm is 1:1:1.

[0050] In a preferred embodiment, in step one, the stirring of alcohol, vegetable pitch, syrup and starch is carried out in a closed stirring container to recover alcohol.

[0051] In a preferred embodiment, the starch is selected from one of corn starch, potato starch, cassava starch, wheat starch and rice starch.

[0052] In the initial stage of mixing, due to the presence of part of alcohol and water, and the starch has not been completely gelatinized, the environmental-friendly binder and the aggregate can be mixed more uniformly. In the later stage of mixing, with the volatilization of alcohol and the gelatinization of starch, the viscosity of the environmental-friendly binder is enhanced, so that the aggregate can be better bonded. Specifically, the gelatinization of starch first absorbs alcohol and water in the syrup, so that the viscosity of the syrup is enhanced, and the change in properties caused by the gelatinization of starch itself can significantly improve the viscosity of itself, so that the aggregate is combined more tightly. The attapulgite is in a dry state when added, which helps the mixing of the aggregate and the environmental-friendly binder. During the mixing process, the attapulgite absorbs water and the viscosity increases significantly, thereby facilitating the tight combination of the aggregate.

[0053] Among numerous environmental-friendly substances with binding properties, the present application selects starch, syrup and vegetable pitch as the main raw materials to prepare a binder suitable for electrode paste after exploration. Among them, starch as a binder has a lower cost, so it can effectively reduce the production cost of electrode paste. However, due to the low viscosity of starch itself, including the viscosity after starch gelatinization, when mixed unevenly, the mechanical strength of the electrode paste after subsequent baking is relatively low, and the electrode paste is prone to breakage. There are three difficulties in preparing a binder from starch, syrup and vegetable pitch and mixing it with aggregate: the first is how to mix the binder of multiple components uniformly, the second is how to mix the binder with the aggregate uniformly, and the third is whether the mechanical strength and porosity of the electrode paste after high-temperature baking can meet the requirements.

[0054] To address the first difficulty, the present invention first adds alcohol to the binder raw materials, then performs gradient mixing, leveraging the inherent properties of each component to achieve the goal of uniformly mixing the binder components. Since alcohol is not required in the electrode paste, and excessive alcohol can lead to excessive volatiles in the electrode paste, affecting the paste's performance, the present invention also utilizes temperature and time in steps three and four to uniformly mix the binder while simultaneously evaporating most of the alcohol, which can then be collected.

[0055] In response to the second and third difficulties, the present invention utilizes the low viscosity of starch when it is not gelatinized at low temperature, and the low viscosity of attapulgite when it is dry, and fully mixes the binder with the aggregate. During the mixing process, the alcohol further evaporates, the starch gelatinization is denatured, and it absorbs water, which not only increases its own viscosity, but also increases the viscosity of the syrup. At the same time, the viscosity of the attapulgite is also significantly increased after absorbing water, thereby making the compactness after kneading higher, and the mechanical strength and porosity are relatively low during subsequent roasting. The following invention will verify the effect of the present invention through Example 4 and Comparative Example.

[0056] Example 5

[0057] 55% pure alcohol, plant pitch, syrup, and starch were mixed in a mass ratio of 20:150:70:90. The alcohol and starch were then stirred at 40 rpm for 2 minutes at 20°C. The syrup was then added and stirred at 80 rpm for 5 minutes at 40°C. The plant pitch was then added and stirred at 40 rpm for 15 minutes at 50°C to produce a bio-based binder. The bio-based binder, aggregate, and attapulgite were then mixed and kneaded to form an electrode paste. The mass ratio of aggregate, bio-based binder, and attapulgite was 80:20:0.7. The kneading temperature was 60°C for 60 minutes. The mixture was then calcined according to the method specified in YS / T63.1-2019 to produce an electrode paste at room temperature.

[0058] Comparative Example 1

[0059] Plant asphalt, syrup, and starch were mixed in a mass ratio of 150:70:90 for 22 minutes at a speed of 50 rpm and an ambient temperature of 50 degrees Celsius to produce a binder. The binder, aggregate, and attapulgite were then kneaded in a mass ratio of 80:20:0.7 at 60 degrees Celsius for 60 minutes. The mixture was then calcined according to the method specified in YS / T63.1-2019 to produce an electrode paste at room temperature.

[0060] Comparative Example 2

[0061] The plant pitch, sugar syrup, starch, 150:70:90 by mass are mixed for 22 minutes at 50 r / min and at 50 degrees Celsius to obtain a binder; the binder, aggregate and attapulgite are mixed and kneaded to form a shape, wherein the mass ratio of the aggregate, binder and attapulgite is 80:20:0.7, and the kneading temperature is 60 degrees Celsius and the time is 60 minutes. After baking according to the method specified in YS / T63.1-2019, the electrode paste is obtained at room temperature.

[0062] Comparative Example Three

[0063] The plant pitch, sugar syrup, starch, 150:70:90 by mass are mixed for 22 minutes at 50 r / min and at 50 degrees Celsius to obtain a binder; the binder, aggregate and attapulgite are mixed and kneaded to form a shape, wherein the mass ratio of the aggregate, binder and attapulgite is 80:20:0.7, and the kneading temperature is 60 degrees Celsius and the time is 60 minutes. After baking according to the method specified in YS / T63.1-2019, the electrode paste is obtained at room temperature.

[0064] Example Five is the electrode paste prepared by the method of the present application; Comparative Example One is the electrode paste prepared without adding alcohol and without following the steps of the bio-based binder of the present application; Comparative Example Two is the electrode paste prepared without adding alcohol, without following the steps of the bio-based binder of the present application, and without adding attapulgite; Comparative Example Three is the electrode paste prepared without adding alcohol, with starch replaced by gelatinized starch, and without following the steps of the bio-based binder of the present application. The experimental results are shown in Table One:

[0065] Table One: Performance of the electrode paste prepared in Example Five and Comparative Examples One, Two and Three

[0066] Porosity (%) Mechanical strength (MPa) Example five 17.6 25.4 Comparative example one 20.9 19.1 Comparative example two 21.8 18.4 Comparative example three 22.3 17.5 Standard 20％ 22

[0067] Among them, the performance of the electrode paste in the standard column is the performance of the electrode paste required by the industry to meet the standard, that is

[0068] Bulk density: Non-ferrous metal industry standard YS / T 63.7;

[0069] Resistivity: Non-ferrous metal industry standard YS / T 63.2;

[0070] Compressive strength: Non-ferrous metal industry standard YS / T 63.15;

[0071] The above experimental results show that, compared with the comparative examples 1 to 3, the electrode paste of the example 5 has significant advantages in the porosity and the mechanical strength, and the electrode paste of the comparative examples 1 to 3 does not reach the standard compared with the performance of the standard electrode paste, and only the electrode paste of the application reaches the standard.

[0072] The above disclosure is only the preferred embodiment of the application, and of course cannot limit the scope of the right of the application, and those skilled in the art can understand that all or part of the above-mentioned embodiments are implemented, and equivalent changes are made according to the claims of the application, which still belongs to the scope covered by the application.

Claims

1. A bio-based binder, characterized in that: The invention comprises alcohol with a purity of 55% to 65%, plant asphalt, syrup and starch, and the mass ratio of alcohol, plant asphalt, syrup and starch is (20-25): (150-170): (70-85): (90-110); and is obtained by the following preparation method: alcohol with a purity of 55% to 65%, plant asphalt, syrup and starch are added into a closed stirring container, and the mass ratio of alcohol, plant asphalt, syrup and starch is (20-25): (150-170): (70-85): (90-110). The method comprises the following steps: mixing the alcohol and starch at a speed of 40-60 r / min, a time of 2-3 min, and an ambient temperature of 20-30 degrees Celsius; continuously adding the syrup and stirring at a speed of 80-100 r / min, a time of 5-8 min, and an ambient temperature of 40-50 degrees Celsius; continuously adding the plant asphalt and stirring at a speed of 40-70 r / min, a time of 10-15 min, and an ambient temperature of 50-55 degrees Celsius to obtain a bio-based binder.

2. The method for preparing a bio-based binder according to claim 1, wherein: The following steps are involved: Step 1: Add 55% to 65% purity alcohol, vegetable asphalt, syrup, and starch into a sealed stirring container and mix them in a mass ratio of (20-25): (150-170): (70-85): (90-110); Step 2: Stir the alcohol and starch at a speed of 40-60 r / min for 2-3 minutes at an ambient temperature of 20-30 degrees Celsius. Step 3: Continue adding syrup and stirring at a speed of 80-100 r / min for 5-8 minutes at an ambient temperature of 40-50 degrees Celsius. Step 4: Continue adding plant asphalt and stirring at a speed of 40-70 r / min for 10-15 minutes at an ambient temperature of 50-55 degrees Celsius to obtain a bio-based binder.

3. The method for preparing a bio-based binder according to claim 2, wherein: In step 1, alcohol, plant pitch, syrup and starch are stirred in a closed stirring container to recover alcohol.

4. The method for preparing a bio-based binder according to claim 2 or 3, wherein: The starch is selected from one of corn starch, potato starch, tapioca starch, wheat starch and rice starch.

5. An electrode paste based on a bio-based binder, characterized in that: The invention comprises 80-90 parts by mass of aggregate, 10-20 parts by mass of a bio-based binder, and 0.7-1.2 parts by mass of attapulgite, wherein the bio-based binder comprises alcohol with a purity of 55%-65%, plant asphalt, syrup, and starch, and the mass ratio of the alcohol, plant asphalt, syrup, and starch is (20-25): (150-170): (70-85): (90-110), and the bio-based binder is the bio-based binder according to claim 1.

6. The method for preparing an electrode paste based on a bio-based binder according to claim 5, wherein: The following steps are involved: Step 1: Add 55%~65% pure alcohol, vegetable asphalt, syrup, and starch into a stirring container and mix them in a mass ratio of (20~25): (150~170): (70~85): (90~110); Step 2: Stir the alcohol and starch at a speed of 40-60 r / min for 2-3 minutes at an ambient temperature of 20-30 degrees Celsius. Step 3: Continue adding syrup and stirring at a speed of 80-100 r / min for 5-8 minutes at an ambient temperature of 40-50 degrees Celsius. Step 4: Continue adding plant asphalt and stirring at a speed of 40-70 r / min for 10-15 minutes at an ambient temperature of 50-55 degrees Celsius to obtain a bio-based binder; Step 5: Mix the bio-based binder, aggregate and attapulgite and knead them for molding, wherein the mass ratio of the aggregate, the environmentally friendly binder and the attapulgite is (80-90): (10-20): (0.7-1.2), the kneading temperature is 55-75 degrees Celsius, and the kneading time is 50-60 minutes.

7. The method for preparing an electrode paste based on a bio-based binder according to claim 6, wherein: The aggregate in step five is selected from one or more carbonaceous particles of electro-calcined anthracite, graphite, petroleum coke, pitch coke and metallurgical coke.

8. The method for preparing an electrode paste based on a bio-based binder according to claim 6, wherein: In the aggregate of step five, the mass ratio of aggregates with particle sizes of 4-12 mm, 2-4 mm, and 0-2 mm is 1:1:

1.

9. The method for preparing an electrode paste based on a bio-based binder according to claim 6, wherein: In step 1, alcohol, plant pitch, syrup and starch are stirred in a closed stirring container to recover alcohol.

10. The method for preparing an electrode paste based on a bio-based binder according to any one of claims 6 to 9, characterized in that: The starch is selected from one of corn starch, potato starch, tapioca starch, wheat starch and rice starch.