Semi-coke powder forming binder and preparation method thereof

Abstract

The invention provides a semi-coke powder forming binder and a preparation method thereof, and belongs to the technical field of binders. Comprising the following steps: S1, adding starch into an acid solution, heating, refluxing, stirring, reacting, centrifuging, adding ethanol, precipitating, filtering, washing and drying to obtain acidolysis starch; s2, adding the acidolysis starch into hydrogen peroxide, stirring for oxidation, adding ethanol for precipitation, filtering, washing and drying to obtain oxidized acidolysis starch; s3, adding the oxidized acidolysis starch into water, adding amylase for enzymolysis, performing enzyme deactivation, adding ethanol for precipitation, filtering, washing and drying to obtain pretreated starch; and S4, mixing the pretreated starch and gelatin, adding the mixture into water, uniformly stirring and mixing, and adding water to adjust the solid content, thereby obtaining the semi-coke powder forming binder. The prepared semi-coke powder forming binder has good film-forming property and cohesiveness, a stable and more uniform binder system is formed, and the comprehensive performance, including bonding strength, flexibility, water resistance and the like, of the binder is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of binders, and particularly relates to a briquetting binder for semi-coke powder and a preparation method thereof. Background Art

[0002] Due to its characteristics of high fixed carbon, high specific resistance, high chemical activity, low ash, low sulfur and low phosphorus, semi-coke has gradually replaced metallurgical coke and is widely used in the production of products such as calcium carbide, ferrosilicon, ferroalloy, ferrosilicon, silicon carbide, ferrochrome, and chemical fertilizer. However, during the production process of crushing, transporting, loading and unloading, and using, 30% of coke powder will be generated. Due to its non-bonding and easy-to-pulverize properties, it cannot be fully utilized and can only be used as low-grade fuels such as power coal and civil use. Therefore, in today's energy-intensive situation, using semi-coke powder to process into pellets instead of using semi-coke is the best way for the chemical industry, calcium carbide industry, and metallurgical industry to reduce consumption and increase income and save expenses.

[0003] Due to the non-bonding and easy-to-pulverize properties of semi-coke powder, a binder needs to be added during the briquetting process of semi-coke powder to keep its shape after briquetting. The requirements for the binder for semi-coke powder briquetting are: low ash content, good bonding performance, and good chemical activity.

[0004] At present, there are several binders used in powder briquetting in China. When these binders are used in the briquetting of semi-coke powder, the briquetting rate of semi-coke powder cannot meet our expected requirements. The low briquetting rate is manifested in that the finished spherical materials produced only account for 30%-50%. The binder for semi-coke powder briquetting has become one of our main problems.

[0005] Chinese Patent Publication Text CN 101781531 A discloses a briquetting binder for semi-coke powder. The binder is prepared by mixing 20%-30% of caustic soda sodium hydroxide solution, 20%-30% of urea solution, and 40%-60% of corn starch by weight percentage, and adding hot water at 60°C - 80°C during mixing to form a briquetting binder for semi-coke powder; wherein the concentration of the sodium hydroxide solution is 0.1%-5%, and the concentration of the urea solution is 0.1%-5%. The formula is simple and practical, and the materials are easy to obtain. After using this binder, the semi-coke powder has good briquetting, low ash content, good bonding performance, and good chemical activity, and the use effect is the same as that of semi-coke, reducing energy waste and protecting the environment, providing a guarantee for reducing production costs and increasing benefits. However, the starch in the briquetting binder for semi-coke powder prepared by this method will undergo a hydrolysis reaction under alkaline conditions to generate simple carbohydrates such as glucose. This reaction rate is relatively slow, but it will change the chemical structure of the starch, thereby reducing its adhesiveness and making the viscosity of the prepared binder not high. Summary of the Invention

[0006] The object of the present invention is to provide a briquetting binder for semi-coke powder and a preparation method thereof, which has good film-forming property and adhesiveness, forms a stable and more uniform binder system, and improves the comprehensive properties of the binder, including bonding strength, flexibility, water resistance, etc.

[0007] The technical solution of the present invention is realized as follows: The present invention provides a preparation method of a briquetting binder for semi-coke powder, comprising the following steps: S1. Acid hydrolysis: Add starch into an acid solution, heat under reflux and stir for reaction, centrifuge, add ethanol for precipitation, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add the acid-hydrolyzed starch into hydrogen peroxide, stir for oxidation, add ethanol for precipitation, filter, wash, and dry to obtain oxidized acid-hydrolyzed starch; S3. Enzymatic hydrolysis: Add the oxidized acid-hydrolyzed starch into water, add amylase for enzymatic hydrolysis, inactivate the enzyme, add ethanol for precipitation, filter, wash, and dry to obtain pretreated starch; S4. Compound: Mix the pretreated starch and gelatin and add them into water, stir and mix evenly, add water to adjust the solid content to obtain a briquetting binder for semi-coke powder.

[0008] As a further improvement of the present invention, in step S1, the solid-liquid ratio of the starch to the acid solution is 1:3 - 5 g / mL.

[0009] As a further improvement of the present invention, in step S1, the acid solution is a 1 - 3 wt% hydrochloric acid or sulfuric acid solution.

[0010] As a further improvement of the present invention, in step S1, the time of the heat reflux stirring reaction is 5 - 8 h.

[0011] As a further improvement of the present invention, in step S2, the concentration of the hydrogen peroxide is 20 - 25 wt%, and the time of the stirring oxidation is 2 - 4 h.

[0012] As a further improvement of the present invention, in step S3, the amylase is α-amylase, β-amylase or γ-amylase.

[0013] As a further improvement of the present invention, in step S3, the mass ratio of the oxidized acid-hydrolyzed starch to the amylase is 100:1 - 2, the temperature of the enzymatic hydrolysis is 35 - 45 °C, and the time is 2 - 4 h.

[0014] As a further improvement of the present invention, in step S4, the mass ratio of the pretreated starch to the gelatin is 10 - 15:3 - 5.

[0015] As a further improvement of the present invention, in step S4, the solid content is 20 - 30 wt%.

[0016] The present invention further protects a semi-coke powder forming binder prepared by the preparation method according to any one of claims 1-9.

[0017] The present invention has the following beneficial effects: Through the acidolysis reaction of the present invention, the starch molecular chain is broken to generate short-chain starch, increasing the reactivity and solubility of starch molecules, improving the compatibility between starch and semi-coke powder, thereby enhancing the bonding performance of the binder. The oxidation reaction further changes the molecular structure of starch, introducing more reactive groups such as aldehyde groups and carboxyl groups. These groups can undergo chemical reactions with the functional groups on the surface of semi-coke powder to form chemical bonds, improving the binding force between the binder and semi-coke powder. The enzymolysis reaction can further decompose starch molecules to make their molecular chains shorter. At the same time, some new functional groups may be introduced during the enzymolysis process, and these functional groups can interact with the functional groups on the surface of semi-coke powder to enhance the bonding performance of the binder.

[0018] In addition, in the present invention, the pretreated starch is compounded with gelatin. Gelatin has good film-forming property and bonding property, and can interact with starch to form a more stable and uniform binder system, improving the comprehensive performance of the binder, including bonding strength, flexibility, water resistance, etc. Specific embodiments

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] Example 1 This example provides a preparation method of a semi-coke powder forming binder, including the following steps: S1. Acidolysis: Add 10 g of starch to 30 mL of 1 wt% hydrochloric acid solution, heat under reflux and stir for 5 h, centrifuge, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add 10 g of acid-hydrolyzed starch to 100 mL of 20 wt% hydrogen peroxide solution, stir and oxidize for 2 h, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain oxidized acid-hydrolyzed starch; S3. Enzymolysis: Add 10 g of oxidized acid-hydrolyzed starch to 200 mL of water, add 0.1 g of α-amylase, enzymolyze at 35 °C for 2 h, inactivate the enzyme, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain pretreated starch; S4. Compound: Mix 10 g of pretreated starch and 3 g of gelatin, add them to water, stir and mix for 10 min, add water to adjust the solid content to 20 wt%, and obtain a binder for briquetting semi-coke powder.

[0021] Example 2 This example provides a method for preparing a binder for briquetting semi-coke powder, including the following steps: S1. Acid hydrolysis: Add 10 g of starch to 50 mL of 3 wt% sulfuric acid solution, heat under reflux and stir for reaction for 8 h, centrifuge, add ethanol to make the ethanol content in the system reach 90 wt%, precipitate, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add 10 g of acid-hydrolyzed starch to 100 mL of 25 wt% hydrogen peroxide solution, stir and oxidize for 4 h, add ethanol to make the ethanol content in the system reach 90 wt%, precipitate, filter, wash, and dry to obtain oxidized acid-hydrolyzed starch; S3. Enzymatic hydrolysis: Add 10 g of oxidized acid-hydrolyzed starch to 200 mL of water, add 0.2 g of γ-amylase, carry out enzymatic hydrolysis at 45 °C for 4 h, inactivate the enzyme, add ethanol to make the ethanol content in the system reach 90 wt%, precipitate, filter, wash, and dry to obtain pretreated starch; S4. Compound: Mix 15 g of pretreated starch and 5 g of gelatin, add them to water, stir and mix for 10 min, add water to adjust the solid content to 30 wt%, and obtain a binder for briquetting semi-coke powder.

[0022] Example 3 This example provides a method for preparing a binder for briquetting semi-coke powder, including the following steps: S1. Acid hydrolysis: Add 10 g of starch to 40 mL of 2 wt% hydrochloric acid solution, heat under reflux and stir for reaction for 6 h, centrifuge, add ethanol to make the ethanol content in the system reach 90 wt%, precipitate, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add 10 g of acid-hydrolyzed starch to 100 mL of 22 wt% hydrogen peroxide solution, stir and oxidize for 3 h, add ethanol to make the ethanol content in the system reach 90 wt%, precipitate, filter, wash, and dry to obtain oxidized acid-hydrolyzed starch; S3. Enzymatic hydrolysis: Add 10 g of oxidized acid-hydrolyzed starch to 200 mL of water, add 0.15 g of β-amylase, carry out enzymatic hydrolysis at 40 °C for 3 h, inactivate the enzyme, add ethanol to make the ethanol content in the system reach 90 wt%, precipitate, filter, wash, and dry to obtain pretreated starch; S4. Compound: Mix 12 g of pretreated starch and 4 g of gelatin, add them to water, stir and mix for 10 min, add water to adjust the solid content to 25 wt%, and obtain a binder for briquetting semi-coke powder.

[0023] Comparative Example 1 Compared with Example 3, the difference lies in that step S1 was not carried out.

[0024] Specifically as follows: S1. Oxidation: Add 10 g of starch to 100 mL of 22 wt% hydrogen peroxide solution, stir and oxidize for 3 h, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain oxidized and acid-hydrolyzed starch; S2. Enzymatic hydrolysis: Add 10 g of oxidized and acid-hydrolyzed starch to 200 mL of water, add 0.15 g of β-amylase, carry out enzymatic hydrolysis at 40 °C for 3 h, inactivate the enzyme, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain pretreated starch; S3. Compound: Mix 12 g of pretreated starch and 4 g of gelatin and add them to water, stir and mix for 10 min, add water to adjust the solid content to 25 wt% to obtain a binder for briquetting semi-coke powder.

[0025] Comparative Example 2 Compared with Example 3, the difference lies in that step S2 was not carried out.

[0026] Specifically as follows: S1. Acid hydrolysis: Add 10 g of starch to 40 mL of 2 wt% hydrochloric acid solution, heat under reflux and stir for 6 h, centrifuge, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Enzymatic hydrolysis: Add 10 g of acid-hydrolyzed starch to 200 mL of water, add 0.15 g of β-amylase, carry out enzymatic hydrolysis at 40 °C for 3 h, inactivate the enzyme, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain pretreated starch; S3. Compound: Mix 12 g of pretreated starch and 4 g of gelatin and add them to water, stir and mix for 10 min, add water to adjust the solid content to 25 wt% to obtain a binder for briquetting semi-coke powder.

[0027] Comparative Example 3 Compared with Example 3, the difference lies in that step S3 was not carried out.

[0028] Specifically as follows: S1. Acid hydrolysis: Add 10 g of starch to 40 mL of 2 wt% hydrochloric acid solution, heat under reflux and stir for 6 h, centrifuge, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add 10 g of acid-hydrolyzed starch to 100 mL of 22 wt% hydrogen peroxide solution, stir and oxidize for 3 h, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain oxidized and acid-hydrolyzed starch; S3. Compound: Mix 12 g of oxidized and acid-hydrolyzed starch and 4 g of gelatin, add them to water, stir and mix for 10 min, add water to adjust the solid content to 25 wt%, and obtain the briquetting binder for semi-coke powder.

[0029] Comparative Example 4 Compared with Example 3, the difference lies in that gelatin is not added in step S4.

[0030] Specifically as follows: S1. Acid hydrolysis: Add 10 g of starch to 40 mL of 2 wt% hydrochloric acid solution, heat under reflux with stirring for 6 h, centrifuge, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add 10 g of acid-hydrolyzed starch to 100 mL of 22 wt% hydrogen peroxide solution, stir and oxidize for 3 h, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain oxidized and acid-hydrolyzed starch; S3. Enzymatic hydrolysis: Add 10 g of oxidized and acid-hydrolyzed starch to 200 mL of water, add 0.15 g of β-amylase, carry out enzymatic hydrolysis at 40 °C for 3 h, inactivate the enzyme, add ethanol until the ethanol content in the system is 90 wt%, precipitate, filter, wash, and dry to obtain the pretreated starch; S4. Compound: Add 12 g of the pretreated starch to water, stir and mix for 10 min, add water to adjust the solid content to 25 wt%, and obtain the briquetting binder for semi-coke powder.

[0031] Test Example 1 Add the briquetting binders for semi-coke powder prepared in Examples 1-3 and Comparative Examples 1-4 and commercially available similar products to semi-coke powder, process into briquettes, and the performance tests are as shown in Table 1 below.

[0032] Table 1

[0033] As can be seen from the above table, the briquettes prepared with the briquetting binders for semi-coke powder prepared in Examples 1-3 of the present invention have better comprehensive performance.

[0034] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A preparation method of a semi-coke powder molding binder, characterized in that, It includes the following steps: S1. Acid hydrolysis: Add starch into an acid solution, heat under reflux with stirring for reaction, centrifuge, add ethanol for precipitation, filter, wash, and dry to obtain acid-hydrolyzed starch; S2. Oxidation: Add the acid-hydrolyzed starch into hydrogen peroxide, stir for oxidation, add ethanol for precipitation, filter, wash, and dry to obtain oxidized acid-hydrolyzed starch; S3. Enzymatic hydrolysis: Add the oxidized acid-hydrolyzed starch into water, add amylase for enzymatic hydrolysis, inactivate the enzyme, add ethanol for precipitation, filter, wash, and dry to obtain pretreated starch; S4. Compound: Mix the pretreated starch and gelatin and add them into water, stir to mix evenly, add water to adjust the solid content to obtain a binder for briquetting semi-coke powder.

2. The preparation method according to claim 1, characterized in that, In step S1, the solid-liquid ratio of the starch and the acid solution is 1:3 - 5 g / mL.

3. The preparation method according to claim 1, wherein In step S1, the acid solution is a 1 - 3 wt% hydrochloric acid or sulfuric acid solution.

4. The preparation method according to claim 1, wherein In step S1, the time for heating under reflux with stirring for reaction is 5 - 8 h.

5. The preparation method according to claim 1, wherein, In step S2, the concentration of the hydrogen peroxide is 20 - 25 wt%, and the time for stirring oxidation is 2 - 4 h.

6. The preparation method according to claim 1, characterized in that, In step S3, the amylase is α-amylase, β-amylase or γ-amylase.

7. The preparation method according to claim 1, characterized in that In step S3, the mass ratio of the oxidized acid-hydrolyzed starch to the amylase is 100:1 - 2, the temperature for enzymatic hydrolysis is 35 - 45 °C, and the time is 2 - 4 h.

8. The preparation method according to claim 1, characterized in that, In step S4, the mass ratio of the pretreated starch to the gelatin is 10 - 15:3 - 5.

9. The preparation method according to claim 1, characterized in that, In step S4, the solid content is 20 - 30 wt%.

10. A binder for briquetting semi-coke powder prepared by the preparation method according to any one of claims 1 - 9.

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