Efficient environment-friendly casting pulverized coal substitute (HH powder for short)

Abstract

The invention discloses an efficient and environment-friendly pulverized coal substitute for casting (HH powder for short), and belongs to the technical field of casting industry, and the efficient and environment-friendly pulverized coal substitute for casting comprises the following components: 40-60% of a multifunctional composite cellulose matrix material; 20%-35% of a nanoscale reinforcing filler; 5%-15% of a slow release additive; the forsterite powder comprises the following components in percentage by weight: 45.60% of MgO, 0.57% of CaO, 41.55% of SiO2 and 8.16% of TFe2O3, and the rest of the forsterite powder is ignition loss, and the forsterite powder comprises the following components in percentage by weight: 45.60% of MgO, 0.57% of CaO, 41.55% of SiO2 and 8.16% of TFe2O3. Through the design of a multifunctional composite cellulose matrix material, natural plant fibers are subjected to high-temperature carbonization treatment to form a porous structure, and a surface hydroxylation modification process is combined, so that a large number of hydrophilic functional groups are introduced on a cellulose molecular chain, and the compatibility with a molding sand system is improved.

Description

Technical Field

[0001] This invention belongs to the field of casting industry technology, and in particular to a high-efficiency and environmentally friendly coal powder substitute for casting (referred to as HH powder). Background Technology

[0002] In modern foundry industry, wet molding sand is widely used as the primary molding material in various casting production processes. To improve the permeability and release properties of the molding sand and reduce sand adhesion, pulverized coal is often added as an auxiliary material. However, with increasingly stringent environmental regulations and growing demands for green manufacturing, the application of pulverized coal faces numerous challenges. Pulverized coal not only produces large amounts of smoke and harmful gases when burned, causing environmental pollution, but its non-renewable nature also contradicts the concept of sustainable development. Therefore, developing a pulverized coal substitute that meets the requirements of casting processes while effectively reducing environmental impact has become a critical issue that the foundry industry urgently needs to address.

[0003] Traditional pulverized coal releases large amounts of harmful gases such as carbon dioxide, sulfur dioxide, and nitrogen oxides during combustion. Studies show that each ton of pulverized coal releases approximately 2,620 kg of carbon dioxide, 8.5 kg of sulfur dioxide, and 7.4 kg of nitrogen oxides during combustion, along with volatile organic compounds such as benzene, toluene, and xylene. These pollutants not only increase greenhouse gas emissions but also severely pollute the atmosphere. Summary of the Invention

[0004] The purpose of this invention is to provide a highly efficient and environmentally friendly alternative to coal powder for casting (referred to as HH powder) to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder), comprising the following components:

[0006] Multifunctional composite cellulose matrix material: 40% to 60%, wherein the multifunctional composite cellulose matrix material is a natural plant fiber that has undergone high-temperature carbonization treatment and surface hydroxylation modification;

[0007] Nanoscale reinforcing filler: 20%–35%, wherein the nanoscale reinforcing filler is a silicate inorganic material treated with titanate coupling agent;

[0008] Sustained-release additive: 5% to 15%, wherein the sustained-release additive is a microcapsule-encapsulated organic compound with temperature-responsive characteristics, wherein the microcapsule encapsulation structure includes a core and a shell, wherein the core is a fatty acid ester compound, and the shell is a polymer film formed of polylactic acid or chitosan, wherein the diameter of the microcapsule is controlled between 5 μm and 50 μm;

[0009] The mixture contains hematite powder, forsterite powder, fly ash from municipal solid waste incineration power generation (referred to as "fly ash"), and alkali. The forsterite powder contains MgO, CaO, SiO2, and TFe2O3 in the following weight percentages: MgO 45.60, CaO 0.57, SiO2 41.55, and TFe2O3 8.16, with the remaining 2.50 being the loss on ignition.

[0010] In this preferred embodiment, the multifunctional composite cellulose matrix material forms a porous structure through the synergistic effect of carbonization and surface hydroxylation, and generates an interfacial reinforcement effect with the nanoscale reinforcing filler. The slow-release additive releases effective components during heating to achieve dynamic regulation of the molding sand demolding performance.

[0011] In this preferred embodiment, the hematite powder is iron oxide ore powder, and the magnesium olivine ore powder and the dust from the municipal solid waste incineration power generation are both 200-mesh powders, mixed in a certain proportion.

[0012] In this preferred embodiment, the carbonization temperature of the natural plant fiber is controlled between 400℃ and 600℃, the carbonization time is between 30 minutes and 90 minutes, the carbonization atmosphere is a nitrogen protective environment, and the surface hydroxylation treatment is carried out by immersion in sodium hydroxide solution with a concentration of 0.5mol / L to 2mol / L for 1 hour to 3 hours. After immersion, the fiber is washed and dried.

[0013] In this preferred embodiment, the nano-scale reinforcing filler is surface-activated by adding 0.5% to 2% of a titanate coupling agent by mass of the filler. The treatment process includes two stages: high-speed stirring and ultrasonic dispersion. The slow-release additive is microencapsulated by spray drying. The inlet air temperature of the spray drying is 100℃ to 140℃, and the outlet air temperature is 60℃ to 80℃. After sieving, the microcapsule particles are retained in the range of 5μm to 50μm for use.

[0014] In a preferred embodiment of this scheme, the HH powder preparation method includes mixing raw materials in a certain proportion to form a powdery material, then dry-stirring the powder to obtain HH powder, and finally packaging and storing it.

[0015] In this preferred embodiment, the HH powder is suitable for wet sand casting processes of ductile iron, gray iron, or aluminum alloy castings, and the proportions of each component can be adjusted according to different alloy types to adapt to different casting conditions.

[0016] In a preferred embodiment of this scheme, the HH powder can also be made into an aqueous slurry and applied to the surface of molding sand by spraying or rolling to form a functional release layer. The solid content of the aqueous slurry is 20% to 40%, and the viscosity is controlled between 50 mPa·s and 150 mPa·s.

[0017] In this preferred embodiment, the HH powder removes harmful substances and ineffective components from the surface of the casting during the casting process, and then easily cleans it through the sand removal process, ensuring the stability of the molding sand quality and facilitating its long-term recycling.

[0018] In this preferred embodiment, the ratio of bentonite to HH powder is 5:5 to 7:3, which is suitable for various boxless, vertical, manual, shock-pressed, and high-pressure mechanical molding processes. Each ton of HH powder can reduce carbon dioxide emissions by 2.7 tons, demonstrating carbon reduction potential. It also significantly reduces oxygen ablation and harmful gas emissions, improving workshop air quality and enhancing casting quality.

[0019] Compared with the prior art, the technical effects and advantages of the present invention are as follows:

[0020] This highly efficient and environmentally friendly coal powder substitute for casting (referred to as HH powder) utilizes a multifunctional composite cellulose matrix material design. After high-temperature carbonization, natural plant fibers form a porous structure, and a surface hydroxylation modification process introduces numerous hydrophilic functional groups into the cellulose molecular chains, improving its compatibility with molding sand systems. This achieves a transformation of cellulose materials from raw biomass to high-performance casting additives: this transformation not only retains the original structural stability but also enhances its functional performance in high-temperature casting processes. It achieves environmentally friendly, low-carbon, and low-gas emission effects: due to its excellent adsorption and permeability, it reduces the emission of carbon dioxide and other harmful gases produced during traditional coal powder combustion.

[0021] By designing nanoscale reinforcing fillers, silicate inorganic materials (such as calcium silicate, magnesium silicate, or zeolite) are incorporated into the system in the form of particles with a diameter of 50nm to 200nm. Due to their high specific surface area and excellent refractory properties, these fillers significantly improve the hot cracking resistance and high-temperature strength of the molding sand. Surface activation treatment of the fillers with titanate coupling agents further enhances the interfacial bonding force between the fillers and the cellulose matrix, thereby achieving a synergistic reinforcing effect between the materials. This results in improved casting surface quality and reduced sand adhesion defects: the small size effect of the nanoscale fillers allows them to be uniformly dispersed in the molding sand, improving the overall structural stability and durability.

[0022] The microcapsule structure design of the slow-release additive allows fatty acid ester compounds to act as the core, encapsulated in a polymer film formed by polylactic acid or chitosan. This maintains stability at room temperature while gradually releasing lubricating components as the casting heating process increases in temperature. This temperature-responsive mechanism enables dynamic control of demolding performance, avoiding lubrication failure or excessive contamination caused by one-time addition. It achieves the technical effects of improving demolding efficiency and reducing scrap rate, ensuring continuous and effective demolding protection throughout the pouring process and preventing sand adhesion or peeling of the casting during the cooling stage. Attached Figure Description

[0023] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0024] Figure 1 This is a production flow diagram of a high-efficiency and environmentally friendly coal powder substitute for casting (referred to as HH powder) according to the present invention.

[0025] Figure 2 This is a TGA-MS data diagram of the present invention;

[0026] Figure 3 The TGA-FTIR spectrum of the coal powder of this invention;

[0027] Figure 4 The TGA-FTIR spectrum of the HH substitute of the present invention;

[0028] Figure 5 The diagram shows the functional groups precipitated from pulverized coal at different temperatures according to the present invention.

[0029] Figure 6 The diagram shows the functional groups precipitated from HH powder at different temperatures according to the present invention. Detailed Implementation

[0030] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention.

[0031] Unless otherwise defined, the directions mentioned herein, such as up, down, left, right, front, back, inside, and outside, are based on the directions shown in the figures of this invention, and are explained here together.

[0032] This embodiment provides, for example Figure 1 - Appendix Figure 6 The high-efficiency and environmentally friendly coal powder substitute for casting (referred to as HH powder) shown includes the following components:

[0033] Multifunctional composite cellulose matrix material: 40%–60%, wherein the multifunctional composite cellulose matrix material is natural plant fiber that has undergone high-temperature carbonization and surface hydroxylation modification. The natural plant fiber is selected from one or more mixtures of bamboo fiber, straw fiber, or bagasse fiber. These fibers themselves contain abundant cellulose structure and possess good adsorption and air permeability. The carbonization temperature of the natural plant fiber is controlled between 400℃ and 600℃, the carbonization time is 30 minutes to 90 minutes, and the carbonization atmosphere is a nitrogen-protected environment. The surface hydroxylation treatment is performed by immersion in a sodium hydroxide solution with a concentration of 0.5 mol / L to 2 mol / L for 1 hour to 3 hours, followed by washing and drying.

[0034] Nanoscale reinforcing filler: 20%–35%, wherein the nanoscale reinforcing filler is a silicate inorganic material treated with a titanate coupling agent, exhibiting high refractoriness and low expansion rate, suitable for high-temperature casting environments. The silicate inorganic material is selected from one or more of calcium silicate, magnesium silicate, or zeolite, with an average particle size controlled within the range of 50 nm–200 nm. The nanoscale reinforcing filler undergoes surface activation treatment by adding 0.5%–2% of a titanate coupling agent by mass, the treatment process including two stages: high-speed stirring and ultrasonic dispersion.

[0035] Sustained-release additive: 5%–15%, wherein the sustained-release additive is a microcapsule-encapsulated organic compound with temperature-responsive characteristics. The microcapsule encapsulation structure includes a core and a shell. The core is a fatty acid ester compound, and the shell is a polymer film formed of polylactic acid or chitosan. The microcapsule diameter is controlled between 5 μm and 50 μm. The sustained-release additive is microcapsulated using a spray drying process. The inlet air temperature of the spray dryer is 100℃–140℃, and the outlet air temperature is 60℃–80℃. After sieving, microcapsule particles of 5 μm–50 μm are retained for use.

[0036] The mixture comprises hematite powder, forsterite powder, municipal solid waste incineration power generation dust (referred to as "fly ash"), and alkali. The forsterite powder contains MgO, CaO, SiO2, and TFe2O3 in the following weight percentages: MgO 45.60, CaO 0.57, SiO2 41.55, and TFe2O3 8.16, with the remaining 2.50 representing loss on ignition. The hematite powder is an iron oxide powder. Both the forsterite powder and the municipal solid waste incineration power generation dust are 200-mesh powders and are mixed in a specific ratio.

[0037] In this embodiment, the dust from municipal solid waste incineration power generation contains approximately 45% calcium oxide and approximately 30% fly ash salts, as well as dioxins and trace heavy metals, mainly in the following aspects:

[0038] (1) Calcium can desulfurize casting products and effectively improve the quality of castings.

[0039] (2) Fly ash can regulate the permeability of molding sand, increase the surface finish of castings, and improve the collapsibility of molding sand.

[0040] (3) Salt can desulfurize and, in synergy with other materials, effectively utilize salt and enhance the quality of castings.

[0041] (4) Dioxins can be completely decomposed at 400℃-850℃, while the temperature of molten iron poured at 1300℃-1500℃ can completely decompose and treat dioxins.

[0042] (5) Heavy metals are present in very small amounts. When exposed to molten iron at a high temperature of around 1400°C, they will seep into the molten iron and be incorporated into the casting, thus achieving effective treatment.

[0043] (6) Throughout the entire process cycle, fly ash is effectively utilized and harmlessly treated, which greatly improves the internal quality of the entire casting product.

[0044] In this embodiment, the raw materials are mixed in a certain proportion to form a powdery material, which is then dry-mixed to obtain HH powder, which is then packaged and stored. The process includes the following steps:

[0045] S1: Select raw materials such as hematite powder, magnesium olivine powder, dust from municipal solid waste incineration power generation (referred to as "fly ash"), and alkali, all of which are in the form of 200-mesh powder, and then mix them in a certain proportion;

[0046] S2: Preparation of coal powder substitute (HH powder): The powdered material mixed in a certain proportion is dry-mixed to obtain the coal powder substitute (HH powder).

[0047] S3: Packaging: The completed coal powder substitute (referred to as HH powder) is packaged in a certain quantity to complete the preparation of coal powder substitute (referred to as HH powder);

[0048] S4: Storage: Store the prepared coal powder substitute (HH powder for short) in a sealed container and keep it dry and ventilated;

[0049] S5: Usage: When using, add the foundry coal powder substitute (referred to as HH powder) and bentonite to the molding sand in a certain proportion, and then stir and mix the sand. By removing harmful substances and ineffective components from the surface of the casting during the casting process, and then easily cleaning it through the sand cleaning process, the quality stability of the molding sand is guaranteed, which is conducive to the long-term recycling of the molding sand.

[0050] In this embodiment, the HH powder is suitable for wet sand casting of ductile iron, gray iron or aluminum alloy castings, and the proportion of each component can be adjusted according to different alloy types to adapt to different casting conditions; the HH powder can also be made into an aqueous slurry and applied to the surface of molding sand by spraying or rolling to form a functional release layer, wherein the solid content of the aqueous slurry is 20% to 40% and the viscosity is controlled between 50 mPa·s and 150 mPa·s.

[0051] In this embodiment, each ton of HH powder can reduce carbon dioxide emissions by 2.7 tons, demonstrating carbon reduction potential. It also significantly reduces oxygen ablation and harmful gas emissions, improving workshop air quality and enhancing casting quality. The ratio of bentonite to HH powder is 5:5 to 7:3, suitable for various boxless, vertical, manual, vibration-pressed, and high-pressure mechanical molding processes.

[0052] It should be noted that, in this document, relational terms such as "one" and "two" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, the phrase "comprising an element defined as..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency and environmentally friendly coal powder substitute for casting (referred to as HH powder), characterized in that, Includes the following components: Multifunctional composite cellulose matrix material: 40% to 60%, wherein the multifunctional composite cellulose matrix material is a natural plant fiber that has undergone high-temperature carbonization treatment and surface hydroxylation modification; Nanoscale reinforcing filler: 20%–35%, wherein the nanoscale reinforcing filler is a silicate inorganic material treated with titanate coupling agent; Sustained-release additive: 5% to 15%, wherein the sustained-release additive is a microcapsule-encapsulated organic compound with temperature-responsive characteristics, wherein the microcapsule encapsulation structure includes a core and a shell, wherein the core is a fatty acid ester compound, and the shell is a polymer film formed of polylactic acid or chitosan, wherein the diameter of the microcapsule is controlled between 5 μm and 50 μm; Hematite powder, forsterite powder, dust from municipal solid waste incineration power generation, and alkali. The forsterite powder contains MgO, CaO, SiO2, and TFe2O3 in the following weight percentages: MgO 45.60, CaO 0.57, SiO2 41.55, and TFe2O3 8.16, with the remaining 2.50 being the loss on ignition.

2. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 1, characterized in that: The multifunctional composite cellulose matrix material forms a porous structure through the synergistic effect of carbonization and surface hydroxylation, and generates an interfacial reinforcement effect with the nanoscale reinforcing filler. The slow-release additive releases effective components during heating to achieve dynamic regulation of the molding sand demolding performance.

3. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 2, characterized in that: The hematite powder is iron oxide ore powder, and the magnesium olivine ore powder and the dust from the municipal solid waste incineration power generation are both 200-mesh dust and are mixed in a certain proportion.

4. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 3, characterized in that: The carbonization temperature of the natural plant fiber is controlled between 400℃ and 600℃, and the carbonization time is between 30 minutes and 90 minutes. The carbonization atmosphere is a nitrogen-protected environment. The surface hydroxylation treatment is carried out by immersion in sodium hydroxide solution with a concentration of 0.5mol / L to 2mol / L and an immersion time of 1 hour to 3 hours. After immersion, the fiber is washed and dried.

5. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 4, characterized in that: The nanoscale reinforcing filler is surface-activated by adding 0.5% to 2% of a titanate coupling agent by mass of the filler. The treatment process includes two stages: high-speed stirring and ultrasonic dispersion. The slow-release additive is microencapsulated by spray drying. The inlet air temperature of the spray drying is 100℃ to 140℃, and the outlet air temperature is 60℃ to 80℃. After sieving, the microcapsule particles are retained in the range of 5μm to 50μm for use.

6. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 5, characterized in that: The method for preparing HH powder includes mixing raw materials in a certain proportion to form a powdery material, then dry-stirring the powder to obtain HH powder, and then packaging and storing it.

7. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 6, characterized in that: The HH powder is suitable for wet sand casting of ductile iron, gray iron or aluminum alloy castings, and the proportion of each component can be adjusted according to different alloy types to adapt to different casting conditions.

8. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 7, characterized in that: The HH powder can also be made into an aqueous slurry and applied to the surface of molding sand by spraying or rolling to form a functional release layer. The aqueous slurry has a solid content of 20% to 40% and a viscosity controlled between 50 mPa·s and 150 mPa·s.

9. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 8, characterized in that: The HH powder removes harmful substances and ineffective components from the surface of the casting during the casting process, and then easily cleans it through the sand removal process, ensuring the stability of the molding sand quality and facilitating its long-term recycling.

10. The high-efficiency and environmentally friendly coal powder substitute for casting (hereinafter referred to as HH powder) according to claim 8, characterized in that: The ratio of bentonite to HH powder is 5:5 to 7:3, which is suitable for various boxless, vertical, manual, shock-pressed, and high-pressure mechanical molding. Each ton of HH powder can reduce carbon dioxide emissions by 2.7 tons, showing potential for carbon reduction. It also significantly reduces oxygen ablation and harmful gas emissions, improving workshop air quality and enhancing casting quality.

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