Method for preparing industrial silicon composite reducing agent by using fruit peel humus

Abstract

The present application relates to a kind of industrial silicon composite reducing agent prepared with fruit skin humus, and belongs to the technical field of composite reducing agent for industrial silicon smelting.The fruit skin is cut into fruit skin particles, water is added to cover the fruit skin particles, then yeast powder is added and sealed for fermentation to obtain fruit skin humus;non-caking coal powder, fruit skin humus, starch, wood powder and microsilica powder are mixed and then ground to clump to obtain a mixture;the mixture is pressed to form a cylindrical pellet embryo;the cylindrical pellet embryo is placed in an argon environment and subjected to microwave calcination, and then cooled to room temperature in the furnace to obtain an industrial silicon composite reducing agent pellet.The industrial silicon composite reducing agent pellet has a strength of 10-14 MPa, a calorific value of 7200-8000 calories / gram, and a caking index of 49-72, which meets the preparation requirements of industrial silicon pellet reducing agent.

Description

Technical Field

[0001] This invention relates to a method for preparing an industrial silicon composite reducing agent using fruit peel humus, belonging to the technical field of composite reducing agents for industrial silicon smelting. Background Technology

[0002] Currently, with the continuous depletion of high-quality resources such as anthracite and coking coal in China, the status of low-rank coal in the energy structure is constantly rising. However, the utilization rate of low-rank coal, which dominates coal resources, when directly used in industrial silicon smelting is extremely low. This often leads to problems such as insufficient use of raw materials, excessive carbon excess coefficient, increased power consumption, and furnace bottom rise, thereby affecting the industrial silicon smelting effect and generating excessively high production costs. Therefore, developing and exploring new reducing agents to achieve efficient and high-quality utilization of low-rank coal has become an important approach to the comprehensive resource utilization of coal resources.

[0003] Fruit peels, a common type of kitchen waste in daily life, contain extremely high levels of moisture and organic matter, making them highly perishable. Improper handling can pose threats to the environment and public health. Currently, the main approach to fruit peel processing is to convert them into resources such as fertilizer, animal feed, or biofuel, achieving green and circular development. However, some fruit peels are discarded in natural environments such as soil and water bodies, where they ferment into humus through microbial processes. This humus has significant potential for utilization but is rarely effectively utilized.

[0004] Combining fruit peel humus and low-rank coal to prepare industrial silicon composite reducing agents can achieve both efficient and clean utilization of waste fruit peel biomass resources, reducing the environmental risks caused by indiscriminate dumping of fruit peels, and efficient and high-quality utilization of low-rank coal. Summary of the Invention

[0005] To address the issues of low efficiency in directly using low-grade, non-sticky whole coal for silicon smelting and increased environmental pressure caused by improper disposal of fruit peels, this invention proposes a method for preparing an industrial silicon composite reducing agent using fruit peel humus. The method involves fermenting and humifying fruit peels to obtain fruit peel humus. Non-sticky coal powder, fruit peel humus, starch, sawdust powder, and microsilica powder are mixed and ground. The binary or multi-functional groups in the fruit peel humus modify the hydroxyl structure of starch, forming a structurally stable cross-linked starch that enhances the binding properties of the composite reducing agent. Adding sawdust and microsilica powder during pellet preparation further improves the porosity, thermal effect, and compressive strength of the composite pellets, achieving efficient resource utilization of waste biomass and effectively increasing the benefits of industrial silicon smelting. This invention mixes low-rank non-caking coal with fruit peel humus, starch, sawdust, and microsilica to obtain novel composite reducing agent pellets with a strength of 10-14 MPa, a calorific value of 7200-8000 kcal / g, and a caking index of 49-72. This achieves clean and efficient utilization of low-rank coal and has significant economic and social benefits.

[0006] A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0007] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground separately to obtain non-sticky coal powder and wood chip powder;

[0008] (2) Chop the fruit peel into fruit peel particles, add water to cover the fruit peel particles, add yeast powder and seal for fermentation to obtain fruit peel humus;

[0009] (3) Mix non-sticky coal powder, fruit peel humus, starch, wood chip powder and silica powder and grind them until they clump together to obtain a mixture.

[0010] (4) The mixture is pressed into a cylindrical pellet embryo.

[0011] (5) The cylindrical pellets were microwave-roasted in an argon atmosphere and cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon.

[0012] The calorific value of the non-sticky coal in step (1) is 5500-6500 kcal / g, and the caking index is 1-8; the calorific value of the wood chips is 4000-4800 kcal / g.

[0013] The organic matter (cellulose, hemicellulose and lignin) content in the peel of step (2) is 20-45 wt% by mass percentage; the peel may be one or more of the following fruits: apple, orange, watermelon, banana, etc.

[0014] Preferably, the amount of yeast powder added is 1-5% of the weight of the fruit peel particles, and the fermentation time is 45-105 days.

[0015] By mass percentage, the humic acid content in the fruit peel humus of step (2) is 15-30%, and the carbon content is 55-60%.

[0016] In step (3), the particle size of the microsilica powder is less than 0.15 mm, and the SiO2 content is 85.2-88.4 wt%.

[0017] By mass percentage, the mixture in step (3) contains 60-75% non-sticky coal, 15-20% fruit peel humus, 5-9% starch, 3-6% sawdust, and 2-5% silica fume.

[0018] The pressing pressure in step (4) is 12-22 MPa, the diameter of the cylindrical blank is 50-65 cm, and the height is 80-100 cm.

[0019] In step (5), the microwave roasting temperature is 400-700℃, the time is 1.5-3.5h, and the microwave power is 2-6kW.

[0020] The composite reducing agent pellets for industrial silicon of this invention have a strength of 10-14 MPa, a calorific value of 7200-8000 kcal / g, and a bonding index of 49-72.

[0021] The principle of industrial silicon composite reducing agent pellets: Fruit peels contain abundant organic matter. Under the catalytic humification of yeast powder, the organic matter in the fruit peels is decomposed by microorganisms to form a stable humic colloid with certain viscosity characteristics. The humic colloid contains abundant humic acid. After adding starch, the binary or multi-functional groups in the humic acid react with the hydroxyl structure of starch alcohol to generate diether bonds and diester groups, which unite the hydroxyl groups of starch molecules, thereby forming a modified cross-linked starch with a multi-dimensional spatial network structure. Cross-linked starch has the characteristics of high gel strength, acid resistance, high thermal stability and high viscosity, which can increase the adhesion and stability of the composite reducing agent. Wood chips are soft and have a considerable calorific value, making them a good loosening agent and heat source, which can effectively improve the thermal effect and porosity of the reducing agent pellets. At the same time, microsilica powder has strong wear resistance and insulation properties. After participating in the preparation of the composite reducing agent, it can further improve the compressive strength and resistivity of the pellets, thereby enhancing the reaction performance of the pellets for silicon smelting and improving product utilization.

[0022] The beneficial effects of this invention are:

[0023] (1) This invention reuses waste fruit peel biomass by fermenting and humifying the fruit peel under certain conditions to obtain humic matter rich in humic acid; and modifies starch by utilizing the binary or multi-functional group structure in humic acid to form cross-linked starch with strong viscosity and stable structure, thereby enhancing the bonding performance of the composite reducing agent.

[0024] (2) This invention utilizes the wood chips produced by wood processing and the microsilica powder by-product formed by industrial silicon smelting to make full use of the loose texture of wood chips, which can adjust the porosity of pellets and the microsilica powder can enhance the compressive strength of composite pellets, further improving the reaction performance of pellet reducing agent, thus improving the efficiency of industrial silicon smelting and reducing energy consumption in the production process.

[0025] (3) The novel composite reducing agent pellets for industrial silicon of the present invention have a strength of 10-14 MPa, a calorific value of 7200-8000 kcal / g, and a bonding index of 49-72, which meet the preparation requirements of industrial silicon pellet reducing agents, meet the needs of industrial silicon production, and can be applied in an industrial manner. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0027] Example 1: A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0028] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground to a particle size of less than 0.15 mm to obtain non-sticky coal powder and wood chip powder; the calorific value of the non-sticky coal is 6000 kcal / g and the caking index is 1; the calorific value of the wood chips is 4500 kcal / g.

[0029] (2) Chop the apple peel into peel particles. The organic matter (cellulose, hemicellulose and lignin) content in the apple peel is 35wt% by weight. Add water to cover the peel particles, then add yeast powder (2% of the peel particle weight) and seal for fermentation for 60 days to obtain peel humus. The humus contains 20% humic acid and 55% carbon by weight.

[0030] (3) The non-sticky coal powder, fruit peel humus, starch, wood chip powder and microsilica powder are mixed and ground until they clump together to obtain a mixture; the microsilica powder has a particle size of less than 0.15 mm and a SiO2 content of 86.9 wt%; by mass percentage, the non-sticky coal accounts for 67%, fruit peel humus accounts for 20%, starch accounts for 8%, wood chips account for 3%, and microsilica powder accounts for 2%;

[0031] (4) The mixture was pressed under a pressure of 15MPa to obtain a cylindrical pellet embryo with a diameter of 62mm and a height of 81mm;

[0032] (5) The cylindrical pellets were microwave-calcined in an argon atmosphere for 2.5 h and then cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon; the microwave calcination temperature was 650 °C and the microwave power was 3 kW.

[0033] In this embodiment, the composite reducing agent pellets for industrial silicon have a strength of 11 MPa, a calorific value of 7500 kcal / g, and a bonding index of 53.

[0034] Example 2: A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0035] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground to a particle size of less than 0.15 mm to obtain non-sticky coal powder and wood chip powder; the calorific value of the non-sticky coal is 5500 kcal / g and the caking index is 5; the calorific value of the wood chips is 4000 kcal / g.

[0036] (2) Chop the rind (watermelon rind) into rind granules. The organic matter (cellulose, hemicellulose and lignin) content in the rind (watermelon rind) is 20wt% by weight. Add water to cover the rind granules, then add yeast powder (1% of the rind granule weight) and seal for fermentation for 45 days to obtain rind humus. The humic acid content in the rind humus is 25% and the carbon content is 58% by weight.

[0037] (3) The non-sticky coal powder, fruit peel humus, starch, wood chip powder and microsilica powder are mixed and ground until they clump together to obtain a mixture; the microsilica powder has a particle size of less than 0.15 mm and a SiO2 content of 85.2 wt%; by mass percentage, the non-sticky coal accounts for 66%, fruit peel humus accounts for 17%, starch accounts for 6%, wood chips account for 6%, and microsilica powder accounts for 5%;

[0038] (4) The mixture was pressed and molded under a pressure of 16MPa to obtain a cylindrical pellet embryo with a diameter of 60mm and a height of 83mm;

[0039] (5) The cylindrical pellets were microwave-calcined in an argon atmosphere for 2 hours and then cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon. The microwave calcination temperature was 450℃ and the microwave power was 4kW.

[0040] In this embodiment, the composite reducing agent pellets for industrial silicon have a strength of 12 MPa, a calorific value of 7800 kcal / g, and a bonding index of 61.

[0041] Example 3: A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0042] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground to a particle size of less than 0.15 mm to obtain non-sticky coal powder and wood chip powder; the calorific value of the non-sticky coal is 5700 kcal / g and the caking index is 4; the calorific value of the wood chips is 4600 kcal / g.

[0043] (2) Chop the fruit peels (banana peels and apple peels) into fruit peel granules. The organic matter (cellulose, hemicellulose and lignin) content of the fruit peels (banana peels and apple peels) is 40wt% by weight. Add water to cover the fruit peel granules, then add yeast powder (the amount of yeast powder added is 3% of the weight of the fruit peel granules) and seal for fermentation for 75 days to obtain fruit peel humus. The humic acid content of the fruit peel humus is 16% and the carbon content is 59% by weight.

[0044] (3) The non-sticky coal powder, fruit peel humus, starch, wood chip powder and microsilica powder are mixed and ground until they clump together to obtain a mixture; the microsilica powder has a particle size of less than 0.15 mm and a SiO2 content of 86.4 wt%; by mass percentage, the non-sticky coal accounts for 60%, fruit peel humus accounts for 20%, starch accounts for 9%, wood chips account for 6%, and microsilica powder accounts for 5%;

[0045] (4) The mixture was pressed and molded under a pressure of 20MPa to obtain a cylindrical pellet embryo with a diameter of 63mm and a height of 82mm;

[0046] (5) The cylindrical pellets were microwave-calcined in an argon atmosphere for 1.5 h and then cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon; the microwave calcination temperature was 700 °C and the microwave power was 2 kW.

[0047] In this embodiment, the composite reducing agent pellets for industrial silicon have a strength of 10 MPa, a calorific value of 7200 kcal / g, and a bonding index of 49.

[0048] Example 4: A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0049] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground to a particle size of less than 0.15 mm to obtain non-sticky coal powder and wood chip powder; the calorific value of the non-sticky coal is 6500 kcal / g and the caking index is 8; the calorific value of the wood chips is 4800 kcal / g.

[0050] (2) Chop the fruit peels (orange peels and watermelon peels) into fruit peel granules. The organic matter (cellulose, hemicellulose and lignin) content of the fruit peels (orange peels and watermelon peels) is 25wt% by weight. Add water to cover the fruit peel granules, then add yeast powder (the amount of yeast powder added is 5% of the weight of the fruit peel granules) and seal for fermentation for 105 days to obtain fruit peel humus. The humic acid content of the fruit peel humus is 15% and the carbon content is 56% by weight.

[0051] (3) The non-sticky coal powder, fruit peel humus, starch, wood chip powder and microsilica powder are mixed and ground until they clump together to obtain a mixture; the microsilica powder has a particle size of less than 0.15 mm and a SiO2 content of 87.3 wt%; by mass percentage, the non-sticky coal accounts for 67%, fruit peel humus accounts for 18%, starch accounts for 7%, wood chips account for 5%, and microsilica powder accounts for 3%;

[0052] (4) The mixture was pressed and molded under a pressure of 18MPa to obtain a cylindrical pellet embryo with a diameter of 65mm and a height of 85mm;

[0053] (5) The cylindrical pellets were microwave-calcined in an argon atmosphere for 2 hours and then cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon. The microwave calcination temperature was 400℃ and the microwave power was 5kW.

[0054] In this embodiment, the composite reducing agent pellets for industrial silicon have a strength of 13 MPa, a calorific value of 7600 kcal / g, and a bonding index of 64.

[0055] Example 5: A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0056] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground to a particle size of less than 0.15 mm to obtain non-sticky coal powder and wood chip powder; the calorific value of the non-sticky coal is 6200 kcal / g and the caking index is 3; the calorific value of the wood chips is 4200 kcal / g.

[0057] (2) Chop the fruit peels (apple peels and watermelon peels) into fruit peel granules. The organic matter (cellulose, hemicellulose and lignin) content of the fruit peels (apple peels and watermelon peels) is 30wt% by weight. Add water to cover the fruit peel granules, then add yeast powder (the amount of yeast powder added is 4% of the weight of the fruit peel granules) and seal for fermentation for 90 days to obtain fruit peel humus. The humic acid content of the fruit peel humus is 30% and the carbon content is 60% by weight.

[0058] (3) The non-sticky coal powder, fruit peel humus, starch, wood chip powder and microsilica powder are mixed and ground until they clump together to obtain a mixture; the microsilica powder has a particle size of less than 0.15 mm and a SiO2 content of 88.4 wt%; by mass percentage, the non-sticky coal accounts for 75%, fruit peel humus accounts for 15%, starch accounts for 5%, wood chips account for 3%, and microsilica powder accounts for 2%;

[0059] (4) The mixture was pressed and molded under a pressure of 10MPa to obtain a cylindrical pellet embryo with a diameter of 61mm and a height of 84mm;

[0060] (5) The cylindrical pellets were microwave-calcined in an argon atmosphere for 3.5 hours and then cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon; the microwave calcination temperature was 550℃ and the microwave power was 3kW.

[0061] In this embodiment, the composite reducing agent pellets for industrial silicon have a strength of 14 MPa, a calorific value of 8000 kcal / g, and a bonding index of 72.

[0062] Example 6: A method for preparing an industrial silicon composite reducing agent using fruit peel humus, the specific steps of which are as follows:

[0063] (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground to a particle size of less than 0.15 mm to obtain non-sticky coal powder and wood chip powder; the calorific value of the non-sticky coal is 5800 kcal / g and the caking index is 7; the calorific value of the wood chips is 4400 kcal / g.

[0064] (2) Chop the fruit peels (watermelon peel and orange peel) into fruit peel granules. The organic matter (cellulose, hemicellulose and lignin) content of the fruit peels (watermelon peel and orange peel) is 45wt% by weight. Add water to cover the fruit peel granules, then add yeast powder (the amount of yeast powder added is 3% of the weight of the fruit peel granules) and seal for fermentation for 45 days to obtain fruit peel humus. The humic acid content of the fruit peel humus is 18% and the carbon content is 57% by weight.

[0065] (3) The non-sticky coal powder, fruit peel humus, starch, wood chip powder and microsilica powder are mixed and ground until they clump together to obtain a mixture; the microsilica powder has a particle size of less than 0.15 mm and a SiO2 content of 87.8 wt%; by mass percentage, the non-sticky coal accounts for 67%, fruit peel humus accounts for 19%, starch accounts for 6%, wood chips account for 4%, and microsilica powder accounts for 4%;

[0066] (4) The mixture was pressed and molded under a pressure of 12MPa to obtain a cylindrical pellet embryo with a diameter of 62mm and a height of 80mm;

[0067] (5) The cylindrical pellets were microwave-calcined in an argon atmosphere for 3 hours and then cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon. The microwave calcination temperature was 600℃ and the microwave power was 6kW.

[0068] In this embodiment, the composite reducing agent pellets for industrial silicon have a strength of 11 MPa, a calorific value of 7700 kcal / g, and a bonding index of 58.

[0069] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for preparing an industrial silicon composite reducing agent using fruit peel humus, characterized in that, The specific steps are as follows: (1) Vacuum-dried non-sticky coal and vacuum-dried wood chips are crushed and ground separately to obtain non-sticky coal powder and wood chip powder; (2) Chop the fruit peel into fruit peel particles, add water to cover the fruit peel particles, add yeast powder and seal for fermentation to obtain fruit peel humus; the organic matter content in the fruit peel is 20-45 wt% by mass, and the amount of yeast powder added is 1-5% of the mass of the fruit peel particles; (3) The non-sticky coal powder, fruit peel humus, starch, sawdust powder and silica powder are mixed and ground until they clump together to obtain a mixture; the fruit peel humus contains 15-30% humic acid and 55-60% carbon; the silica powder has a particle size of less than 0.15mm and a SiO2 content of 85.2-88.4wt%. (4) The mixture is pressed into cylindrical pellet embryos; (5) The cylindrical pellets were microwave-roasted in an argon atmosphere and cooled to room temperature in the furnace to obtain composite reducing agent pellets for industrial silicon.

2. The method for preparing industrial silicon composite reducing agent using fruit peel humus according to claim 1, characterized in that: The calorific value of the non-sticky coal in step (1) is 5500~6500 kcal / g, and the caking index is 1~8; the calorific value of the wood chips is 4000~4800 kcal / g.

3. The method for preparing industrial silicon composite reducing agent using fruit peel humus according to claim 1, characterized in that: The fermentation process takes 45 to 105 days.

4. The method for preparing industrial silicon composite reducing agent using fruit peel humus according to claim 1, characterized in that: In terms of mass percentage, the mixture in step (3) contains 60-75% non-sticky coal, 15-20% fruit peel humus, 5-9% starch, 3-6% sawdust, and 2-5% silica fume.

5. The method for preparing industrial silicon composite reducing agent using fruit peel humus according to claim 1, characterized in that: Step (4) The pressing pressure is 12~22MPa, the diameter of the cylindrical blank is 50~65cm, and the height is 80~100cm.

6. The method for preparing industrial silicon composite reducing agent using fruit peel humus according to claim 1, characterized in that: Step (5) The microwave roasting temperature is 400~700℃, the time is 1.5~3.5h, and the microwave power is 2~6kW.