Synthesis method and application of non-toxic and environment-friendly composite inoculant

Abstract

The application discloses a synthetic method of a non-toxic environment-friendly type composite inoculant and application thereof, and belongs to the technical field of casting materials. According to mass parts, components of the inoculant are as follows: silicon (Si): 35-50 parts; calcium (Ca): 2-5 parts; strontium (Sr): 1-3 parts; zirconium (Zr): 0.5-2 parts; scandium (Sc): 0.3-1.2 parts; ytterbium (Yb): 0.2-0.8 parts; aluminum (Al): 0.8-2.5 parts; and iron (Fe): 1-2 parts. In the application, scandium and ytterbium, two heavy rare earth elements, are cooperatively matched, and are combined with silicon, calcium, strontium, zirconium and other elements to form a multi-element composite system.

Description

Technical Field

[0001] This invention belongs to the field of casting materials technology, specifically relating to a method for synthesizing a non-toxic and environmentally friendly composite inoculant and its application. Background Technology

[0002] As is well known, inoculation is a crucial process in metal casting. This process primarily involves adding inoculants to the molten metal to provide heterogeneous nucleation sites, refine grain size, and improve microstructure, thereby enhancing the mechanical properties, corrosion resistance, and machinability of the casting. Currently, widely used industrial inoculants are mainly classified into silicon-based, rare-earth-based, and titanium-zirconium-based types. However, existing inoculants have several drawbacks: 1. Poor environmental friendliness (some inoculants contain toxic heavy metals or release harmful gases during synthesis and use). This process not only pollutes the production environment but also harms the health of operators, failing to meet the requirements of modern green and environmentally friendly industrial development. Furthermore, some silicon-based inoculants have excessively high aluminum content, easily introducing inclusions, affecting the purity of the casting, and increasing environmental remediation costs. 2. Limited and rapid degradation of inoculation effect: Traditional single-component inoculants (such as ferrosilicon and ferrotitanium) have limited nucleation efficiency, making it difficult to simultaneously achieve grain refinement and microstructure uniformity. Existing composite inoculants mostly use conventional rare earth elements (cerium, lanthanum) combined with silicon, calcium, and other elements. Their inoculation effect is easily affected by the temperature of the molten iron and the holding time, resulting in rapid degradation and large fluctuations in casting performance, making it difficult to meet the performance requirements of high-end castings. 3. Complex synthesis process and high cost; 4. Poor versatility and other defects.

[0003] While there is some research on environmentally friendly inoculants in the existing technology, many of them suffer from problems such as unreasonable component matching, difficulty in balancing inoculant effect and environmental performance, or high degree of duplication of technical solutions with prior patents. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention discloses a method for synthesizing a non-toxic and environmentally friendly composite inoculant and its application. In this invention, scandium and ytterbium, two heavy rare earth elements, are synergistically combined with elements such as silicon, calcium, strontium, and zirconium to form a multi-element composite system.

[0005] This invention is implemented as follows:

[0006] A non-toxic and environmentally friendly composite inoculant, comprising the following components: silicon (Si): 35-50 parts; calcium (Ca): 2-5 parts; strontium (Sr): 1-3 parts; zirconium (Zr): 0.5-2 parts; scandium (Sc): 0.3-1.2 parts; ytterbium (Yb): 0.2-0.8 parts; aluminum (Al): 0.8-2.5 parts; iron (Fe): 1-2 parts. The synergistic effect of these components significantly improves nucleation efficiency and resistance to inoculation degradation, distinguishing it from existing single rare earth or conventional rare earth combinations.

[0007] Furthermore, the composite inoculant has a particle size of 0.2~2.0 mm and a bulk density of 2.8~3.2 g / cm³. 3 It has good fluidity and is easy to disperse evenly in molten metal.

[0008] The method for synthesizing a non-toxic and environmentally friendly composite inoculant according to the present invention is as follows:

[0009] Step 1: Raw material pretreatment;

[0010] Step 2: Mix the ingredients;

[0011] Step 3: Low-temperature melting reaction; the mixed raw materials are fed into a medium-frequency induction furnace, and an inert protective gas (argon, purity ≥99.99%) is introduced at a flow rate of 0.8~1.2L / min; the furnace temperature is controlled to rise to 1150~1250℃ at a heating rate of 5~8℃ / min. After the raw materials are completely melted, the reaction is maintained at a constant temperature for 20~30min, with stirring every 5min at a stirring speed of 80~100r / min to ensure that all elements react fully and form a uniform alloy melt; this invention adopts a low-temperature melting process, which reduces energy consumption by 15~20% compared to existing high-temperature melting (above 1300℃), and avoids the generation of harmful gases at high temperatures. At the same time, the inert gas protection prevents the oxidation of raw materials and improves the purity of the inoculant.

[0012] Step 4: Gradient cooling molding;

[0013] Step 5: Post-processing; Crush and sieve the blocky composite inoculant to obtain granular composite inoculant with a particle size of 0.2~2.0mm; Place the sieved inoculant into a sealed bag and vacuum pack it to obtain the finished product.

[0014] Furthermore, step 1 specifically includes:

[0015] Select high-purity raw materials: industrial silicon (purity ≥99.8%), metallic calcium (purity ≥99.5%), metallic strontium (purity ≥99.0%), metallic zirconium (purity ≥99.2%), metallic scandium (purity ≥99.5%), metallic ytterbium (purity ≥99.5%), industrial pure iron (purity ≥99.7%), and industrial aluminum (purity ≥99.6%). Crush all raw materials to a particle size ≤5mm, remove surface oxide scale and impurities, and then dry them in a drying oven at 100~120℃ for 2~3 hours to remove moisture.

[0016] Furthermore, the purity of the industrial silicon is ≥99.8%, the purity of the metallic calcium is ≥99.5%, the purity of the metallic strontium is ≥99.0%, the purity of the metallic zirconium is ≥99.2%, the purity of the metallic scandium is ≥99.5%, the purity of the metallic ytterbium is ≥99.5%, the purity of the industrial pure iron is ≥99.7%, and the purity of the industrial aluminum is ≥99.6%.

[0017] Further, step 2 specifically involves: accurately weighing each pretreated raw material according to the above component mass percentages and placing it into a planetary mixer; adding 0.1~0.3% of the total mass of the raw materials as an environmentally friendly dispersant to the mixer, mixing at a speed of 200~300 r / min and for a mixing time of 30~45 min to obtain a uniformly mixed raw material.

[0018] Furthermore, the dispersant is a mixture of nano-silica and corn starch.

[0019] Further, step 4 specifically involves: slowly pouring the molten alloy melt into a graphite mold preheated to 200-250°C, allowing it to cool naturally in air to 600-700°C, and then transferring it to a heat-insulating box for cooling to room temperature at a rate of 10-15°C / h, thereby obtaining a block-shaped composite inoculant. The inoculant of this invention can be used in molten metal.

[0020] The advantages of this invention over the prior art are as follows:

[0021] This invention is applicable to the casting inoculation treatment of metal materials such as cast iron and aluminum alloys. It can be widely used in the casting fields of automotive parts, machinery manufacturing, and aerospace parts, taking into account both inoculation effect and environmental performance, and solving the technical problems of existing inoculants being toxic, harmful, polluting the environment, and having rapid inoculation degradation.

[0022] The method of this invention has a simple synthesis process, low cost, and no harmful gas emissions. The synthesized composite inoculant does not contain any toxic heavy metal elements, has excellent environmental performance, and also has the characteristics of high nucleation efficiency, stable inoculation effect, strong anti-fading ability, and wide versatility. It can effectively refine the grains of various metal melts, improve the overall performance of castings, and the technical solution is significantly different from existing patents, avoiding duplication.

[0023] The method of this invention is environmentally friendly and non-toxic throughout. The composite inoculant of this invention does not contain any toxic heavy metal elements such as lead, cadmium, and chromium, and the content of harmful impurities is far below the national environmental protection standards. The synthesis process uses an environmentally friendly dispersant, and there is no emission of harmful gases, wastewater, or waste residue, achieving clean production. No toxic or harmful substances are generated during use, which protects the health of operators and avoids environmental pollution, completely solving the problem of poor environmental performance of existing inoculants, and forming a significant difference from existing patents of toxic or highly polluting inoculants.

[0024] Stable inoculation effect and strong anti-fading ability: This invention uses scandium and ytterbium, two heavy rare earth elements, in combination with silicon, calcium, strontium, zirconium and other elements to form a multi-element composite system, which can produce a variety of heterogeneous nucleation particles such as Al3Zr, ScYbSi, CaSi2, etc., and significantly improve the nucleation efficiency. Compared with existing single rare earth or conventional rare earth composite inoculants, the anti-fading ability of the inoculant of this invention is improved by more than 50%. After the melt is held at a constant temperature for 60 minutes, the inoculation effect decay rate is only 6~8%, which is far lower than the 30~40% of traditional inoculants, ensuring uniform and stable casting performance. Detailed Implementation

[0025] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the following examples provide a more detailed description of the invention. It should be noted that the specific embodiments described herein are merely illustrative and not intended to limit the scope of the invention.

[0026] Example 1

[0027] The synthesis method in this embodiment is as follows:

[0028] Step 1: Raw material pretreatment; Select high-purity raw materials: industrial silicon (purity ≥99.8%), metallic calcium (purity ≥99.5%), metallic strontium (purity ≥99.0%), metallic zirconium (purity ≥99.2%), metallic scandium (purity ≥99.5%), metallic ytterbium (purity ≥99.5%), industrial pure iron (purity ≥99.7%), and industrial aluminum (purity ≥99.6%); Crush all raw materials to a particle size ≤5mm, remove surface oxide scale and impurities, and then dry them in a drying oven at 100~120℃ for 2~3 hours to remove moisture, and set aside for later use.

[0029] Step 2: Ingredient Mixing; Accurately weigh each pretreated raw material according to the above component mass proportions and place them into a planetary mixer; Add 0.1~0.3% of the total mass of the raw materials to the mixer, mix at a speed of 200~300 r / min for 30~45 min, and obtain a uniformly mixed raw material.

[0030] Step 3: Low-temperature melting reaction; A mixture of silicon (Si): 40 parts; calcium (Ca): 3 parts; strontium (Sr): 1 part; zirconium (Zr): 1.5 parts; scandium (Sc): 1 part; ytterbium (Yb): 0.4 parts; aluminum (Al): 1.5 parts; and iron (Fe): 1.5 parts is fed into a medium-frequency induction furnace. An inert protective gas (argon, purity ≥99.99%) is introduced at a flow rate of 0.8~1.2 L / min. The furnace temperature is controlled to rise to 1150~1250℃ at a rate of 5~8℃ / min. After the raw materials are completely melted, the reaction is maintained at a constant temperature for 20~30 min. During this period, the mixture is stirred every 5 min at a speed of 80~100 r / min to ensure that all elements react fully and form a homogeneous alloy melt.

[0031] Step 4: Gradient cooling molding; The molten alloy melt is slowly poured into a graphite mold preheated to 200~250℃, and then naturally cooled in the air to 600~700℃. Then it is transferred to a heat preservation box and cooled to room temperature at a rate of 10~15℃ / h to obtain a blocky composite inoculant.

[0032] Step 5: Post-processing; Crush and sieve the blocky composite inoculant to obtain granular composite inoculant with a particle size of 0.2~2.0mm; Place the sieved inoculant into a sealed bag and vacuum pack it to obtain the finished product.

[0033] Example 2

[0034] The synthesis method in this embodiment is as follows:

[0035] Step 1: Raw material pretreatment; Select high-purity raw materials: industrial silicon (purity ≥99.8%), metallic calcium (purity ≥99.5%), metallic strontium (purity ≥99.0%), metallic zirconium (purity ≥99.2%), metallic scandium (purity ≥99.5%), metallic ytterbium (purity ≥99.5%), industrial pure iron (purity ≥99.7%), and industrial aluminum (purity ≥99.6%); Crush all raw materials to a particle size ≤5mm, remove surface oxide scale and impurities, and then dry them in a drying oven at 100~120℃ for 2~3 hours to remove moisture, and set aside for later use.

[0036] Step 2: Ingredient Mixing; Accurately weigh each pretreated raw material according to the above component mass proportions and place them into a planetary mixer; Add 0.1~0.3% of the total mass of the raw materials to the mixer, mix at a speed of 200~300 r / min for 30~45 min, and obtain a uniformly mixed raw material.

[0037] Step 3: Low-temperature melting reaction; A mixture of silicon (Si): 50 parts; calcium (Ca): 5 parts; strontium (Sr): 3 parts; zirconium (Zr): 2 parts; scandium (Sc): 1.2 parts; ytterbium (Yb): 0.8 parts; aluminum (Al): 2.5% parts; and iron (Fe): 1-2 parts is fed into a medium-frequency induction furnace. An inert protective gas (argon, purity ≥99.99%) is introduced at a flow rate of 0.8-1.2 L / min. The furnace temperature is controlled to rise to 1150-1250℃ at a rate of 5-8℃ / min. After the raw materials are completely melted, the reaction is maintained at a constant temperature for 20-30 minutes, with stirring every 5 minutes at a speed of 80-100 r / min to ensure that all elements react fully and form a homogeneous alloy melt.

[0038] Step 4: Gradient cooling molding; The molten alloy melt is slowly poured into a graphite mold preheated to 200~250℃, and then naturally cooled in the air to 600~700℃. Then it is transferred to a heat preservation box and cooled to room temperature at a rate of 10~15℃ / h to obtain a blocky composite inoculant.

[0039] Step 5: Post-processing; Crush and sieve the blocky composite inoculant to obtain granular composite inoculant with a particle size of 0.2~2.0mm; Place the sieved inoculant into a sealed bag and vacuum pack it to obtain the finished product.

[0040] Example 3

[0041] The synthesis method in this embodiment is as follows:

[0042] Step 1: Raw material pretreatment; Select high-purity raw materials: industrial silicon (purity ≥99.8%), metallic calcium (purity ≥99.5%), metallic strontium (purity ≥99.0%), metallic zirconium (purity ≥99.2%), metallic scandium (purity ≥99.5%), metallic ytterbium (purity ≥99.5%), industrial pure iron (purity ≥99.7%), and industrial aluminum (purity ≥99.6%); Crush all raw materials to a particle size ≤5mm, remove surface oxide scale and impurities, and then dry them in a drying oven at 100~120℃ for 2~3 hours to remove moisture, and set aside for later use.

[0043] Step 2: Ingredient Mixing; Accurately weigh each pretreated raw material according to the above component mass proportions and place them into a planetary mixer; Add 0.1~0.3% of the total mass of the raw materials to the mixer, mix at a speed of 200~300 r / min for 30~45 min, and obtain a uniformly mixed raw material.

[0044] Step 3: Low-temperature melting reaction; A mixture of silicon (Si): 35 parts; calcium (Ca): 2 parts; strontium (Sr): 1 part; zirconium (Zr): 0.5 parts; scandium (Sc): 0.3 parts; ytterbium (Yb): 0.2 parts; aluminum (Al): 0.8-2.5 parts; iron (Fe): 1 part is fed into a medium-frequency induction furnace, and an inert protective gas (argon, purity ≥99.99%) is introduced at a flow rate of 0.8-1.2 L / min; The furnace temperature is controlled to rise to 1150-1250℃ at a heating rate of 5-8℃ / min. After the raw materials are completely melted, the reaction is maintained at a constant temperature for 20-30 minutes, and the mixture is stirred every 5 minutes at a stirring speed of 80-100 r / min to ensure that all elements react fully and form a homogeneous alloy melt;

[0045] Step 4: Gradient cooling molding; The molten alloy melt is slowly poured into a graphite mold preheated to 200~250℃, and then naturally cooled in the air to 600~700℃. Then it is transferred to a heat preservation box and cooled to room temperature at a rate of 10~15℃ / h to obtain a blocky composite inoculant.

[0046] Step 5: Post-processing; Crush and sieve the blocky composite inoculant to obtain granular composite inoculant with a particle size of 0.2~2.0mm; Place the sieved inoculant into a sealed bag and vacuum pack it to obtain the finished product.

[0047] Example 4

[0048] The synthesis method in this embodiment is as follows:

[0049] Step 1: Raw material pretreatment; Select high-purity raw materials: industrial silicon (purity ≥99.8%), metallic calcium (purity ≥99.5%), metallic strontium (purity ≥99.0%), metallic zirconium (purity ≥99.2%), metallic scandium (purity ≥99.5%), metallic ytterbium (purity ≥99.5%), industrial pure iron (purity ≥99.7%), and industrial aluminum (purity ≥99.6%); Crush all raw materials to a particle size ≤5mm, remove surface oxide scale and impurities, and then dry them in a drying oven at 100~120℃ for 2~3 hours to remove moisture, and set aside for later use.

[0050] Step 2: Ingredient Mixing; Accurately weigh each pretreated raw material according to the above component mass proportions and place them into a planetary mixer; Add 0.1~0.3% of the total mass of the raw materials to the mixer, mix at a speed of 200~300 r / min for 30~45 min, and obtain a uniformly mixed raw material.

[0051] Step 3: Low-temperature melting reaction; A mixture of silicon (Si): 40 parts; calcium (Ca): 3 parts; strontium (Sr): 2 parts; zirconium (Zr): 1 part; scandium (Sc): 1 part; ytterbium (Yb): 0.6 parts; aluminum (Al): 2 parts; and iron (Fe): 1.5 parts is fed into a medium-frequency induction furnace. An inert protective gas (argon, purity ≥99.99%) is introduced at a flow rate of 0.8~1.2 L / min. The furnace temperature is controlled to rise to 1150~1250℃ at a rate of 5~8℃ / min. After the raw materials are completely melted, the reaction is maintained at a constant temperature for 20~30 min. During this period, the mixture is stirred every 5 min at a speed of 80~100 r / min to ensure that all elements react fully and form a homogeneous alloy melt.

[0052] Step 4: Gradient cooling molding; The molten alloy melt is slowly poured into a graphite mold preheated to 200~250℃, and then naturally cooled in the air to 600~700℃. Then it is transferred to a heat preservation box and cooled to room temperature at a rate of 10~15℃ / h to obtain a blocky composite inoculant.

[0053] Step 5: Post-processing; Crush and sieve the blocky composite inoculant to obtain granular composite inoculant with a particle size of 0.2~2.0mm; Place the sieved inoculant into a sealed bag and vacuum pack it to obtain the finished product.

[0054] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be considered within the scope of protection of the present invention.

Claims

1. A non-toxic and environmentally friendly composite inoculant, characterized in that, The components of the inoculant, by weight, are as follows: Silicon (Si): 35 to 50 parts; Calcium (Ca): 2 to 5 parts; Strontium (Sr): 1 to 3 parts; Zirconium (Zr): 0.5 to 2 parts; Scandium (Sc): 0.3 parts to 1.2 parts; Ytterbium (Yb): 0.2 parts to 0.8 parts; Aluminum (Al): 0.8 parts to 2.5 parts; Iron (Fe): 1 to 2 parts.

2. The non-toxic and environmentally friendly composite inoculant according to claim 1, characterized in that, The composite inoculant has a particle size of 0.2~2.0 mm and a bulk density of 2.8~3.2 g / cm³. 3 .

3. The method for synthesizing a non-toxic and environmentally friendly composite probiotic according to claim 1, characterized in that, The synthesis method is as follows: Step 1: Raw material pretreatment; Step 2: Mix the ingredients; Step 3: Low-temperature melting reaction; Silicon (Si): 35-50 parts; Calcium (Ca): 2-5 parts; Strontium (Sr): 1-3 parts; Zirconium (Zr): 0.5-2 parts; Scandium (Sc): 0.3-1.2 parts; Ytterbium (Yb): 0.2 parts to 0.8 parts; Aluminum (Al): 0.8 parts to 2.5 parts; Iron (Fe): 1 part to 2 parts. The mixed raw materials are fed into a medium-frequency induction furnace, and an inert protective gas (argon, purity ≥99.99%) is introduced at a flow rate of 0.8 to 1.2 L / min. The furnace temperature is controlled to rise to 1150 to 1250℃ at a heating rate of 5 to 8℃ / min. After the raw materials are completely melted, the reaction is maintained at a constant temperature for 20 to 30 minutes. During this period, the mixture is stirred every 5 minutes at a stirring speed of 80 to 100 r / min to ensure that all elements react fully and form a homogeneous alloy melt. Step 4: Gradient cooling molding; Step 5: Post-processing; Crush and sieve the blocky composite inoculant to obtain granular composite inoculant with a particle size of 0.2~2.0mm; Place the sieved inoculant into a sealed bag and vacuum pack it to obtain the finished product.

4. The method for synthesizing a non-toxic and environmentally friendly composite probiotic according to claim 3, characterized in that, Step 1 specifically includes: Select high-purity raw materials: industrial silicon, metallic calcium, metallic strontium, metallic zirconium, metallic scandium, metallic ytterbium, industrial pure iron, and industrial aluminum; crush all raw materials to a particle size ≤5mm, remove surface oxide scale and impurities, and then place them in a drying oven at 100~120℃ for 2~3 hours to remove moisture, and set aside for later use.

5. The method for synthesizing a non-toxic and environmentally friendly composite probiotic according to claim 4, characterized in that, The purity of the industrial silicon is ≥99.8%, the purity of the metallic calcium is ≥99.5%, the purity of the metallic strontium is ≥99.0%, the purity of the metallic zirconium is ≥99.2%, the purity of the metallic scandium is ≥99.5%, the purity of the metallic ytterbium is ≥99.5%, the purity of the industrial pure iron is ≥99.7%, and the purity of the industrial aluminum is ≥99.6%.

6. The method for synthesizing a non-toxic and environmentally friendly composite probiotic according to claim 3, characterized in that, Step 2 specifically involves: accurately weighing each pretreated raw material according to the above component mass percentages and placing them into a planetary mixer; adding 0.1-0.3% of the total mass of the raw materials as an environmentally friendly dispersant to the mixer, mixing at a speed of 200-300 r / min for 30-45 min to obtain a uniformly mixed raw material.

7. The method for synthesizing a non-toxic and environmentally friendly composite probiotic according to claim 6, characterized in that, The dispersant is a mixture of nano-silica and corn starch.

8. The method for synthesizing a non-toxic and environmentally friendly composite probiotic according to claim 3, characterized in that, Step 4 specifically involves: slowly pouring the molten alloy melt into a graphite mold preheated to 200-250°C, allowing it to cool naturally in the air to 600-700°C, and then transferring it to an insulated box to cool it to room temperature at a rate of 10-15°C / h to obtain a blocky composite inoculant.

9. A progester prepared by the synthesis method of a non-toxic and environmentally friendly composite progester as described in any one of claims 3 to 8, characterized in that, The application of the inoculant in molten metal.