A recycled concrete made of semiconductor waste residues and a method for manufacturing the same

Abstract

The application relates to the technical field of recycled concrete, in particular to recycled concrete made of semiconductor waste residues and a preparation method thereof. The recycled concrete made of semiconductor waste residues is prepared from the following raw materials in parts by weight: 90-100 parts of modified semiconductor waste residues, 70-80 parts of sand, 20-30 parts of cement, 10-20 parts of fly ash, 5-10 parts of mineral powder, 1-3 parts of an additive and 15-20 parts of water. The recycled concrete is prepared from the semiconductor waste residues, the semiconductor waste residues are reasonably utilized, and the strength of the prepared recycled concrete is improved.

Description

Technical Field

[0001] This application relates to the field of recycled concrete technology, and in particular to a recycled concrete made from semiconductor waste and its preparation method. Background Technology

[0002] Recycled concrete refers to a new type of concrete made by crushing, washing, and grading waste concrete, mixing it with other aggregates in a certain proportion, and partially or completely replacing natural aggregates such as sand and gravel (mainly coarse aggregates), then adding cement and water. However, compared to natural aggregates, waste concrete has a rough surface and high porosity, resulting in low compressive strength after solidification. Therefore, developing a high-strength recycled concrete is of great significance.

[0003] To address the limitations of recycled concrete's strength, patent application number 202110537627.0 employs a synergistic combination of terpene phenolic resin, sulfur-alkali aluminum, and silica fume to effectively enhance the mechanical properties of recycled concrete, thereby improving its overall crack resistance, compressive strength, and impermeability. However, this patent utilizes an external reinforcing agent, which not only involves a complex preparation process but also suffers from poor economic efficiency.

[0004] Common semiconductor materials include silicon, germanium, and gallium arsenide, with silicon being the most widely used. With the rapid development of technology, semiconductors are being updated and replaced at an increasingly faster pace, resulting in a growing amount of semiconductor waste. Traditional methods for disposing of waste semiconductors include sanitary landfill, high-temperature composting, and incineration, all of which cause significant environmental pollution.

[0005] Therefore, the inventors applied semiconductor waste to recycled concrete, which not only achieved the harmless treatment of toxic waste and made reasonable use of semiconductor waste, but also improved the strength of the recycled concrete. Summary of the Invention

[0006] In order to achieve harmless treatment of semiconductor waste and improve the strength of the concrete produced, this application provides a method for preparing recycled concrete made from semiconductor waste.

[0007] In a first aspect, this application provides a recycled concrete made from semiconductor waste, employing the following technical solution:

[0008] A type of recycled concrete made from semiconductor waste includes the following raw materials in parts by weight: 90-100 parts modified semiconductor waste, 70-80 parts sand, 20-30 parts cement, 10-20 parts fly ash, 5-10 parts mineral powder, 1-3 parts admixtures and 15-20 parts water.

[0009] By adopting the above technical solution, semiconductor waste residue has good hardness. Adding it to concrete can not only make the semiconductor waste residue harmless and reasonable, but also improve the strength of the recycled concrete.

[0010] Preferably, the modified semiconductor waste residue is obtained by using alkali-modified semiconductor waste residue, wherein the alkali is one of sodium hydroxide, potassium hydroxide, magnesium hydroxide, calcium hydroxide, and ammonia water.

[0011] By adopting the above technical solution, the alkali neutralizes the hydrofluoric acid contained in the semiconductor, making the modified semiconductor waste neutral; at the same time, the alkaline substance can promote the formation of hydrated silicates in concrete, thereby improving the strength of concrete; the alkaline substance can improve the corrosion resistance of concrete, reduce microcracks and pores in concrete, and improve the durability and impermeability of concrete.

[0012] Preferably, the alkali is sodium hydroxide.

[0013] By adopting the above technical solution, sodium hydroxide can not only neutralize the hydrofluoric acid in semiconductor waste to make the modified semiconductor neutral, but also react with silicates in concrete to generate calcium silicate cement, thereby improving the strength and durability of concrete. In addition, sodium hydroxide can also accelerate the solidification of concrete and shorten the pouring and curing time.

[0014] Preferably, the modified semiconductor waste is prepared by mixing and reacting semiconductor waste with alkali; the solid-liquid ratio of semiconductor waste to alkali is 1:(3-4); the molar concentration of alkali is 15-20 mol / L, the reaction temperature is 30-35℃, and the reaction time is 50-60 min.

[0015] By adopting the above technical solution, the modified semiconductor waste residue can be prepared without special equipment and complex processes. The preparation method is simple and highly feasible.

[0016] Within an appropriate range, optimize the solid-liquid ratio, molar concentration of alkali, reaction temperature, and time during the reaction of semiconductor waste with alkali to make the semiconductor waste neutral, which is beneficial to the overall strength of concrete.

[0017] Preferably, it also includes 3-9 parts of an adhesive, which is obtained by modifying epoxy resin structural adhesive with hydroxyapatite.

[0018] By adopting the above technical solution, the viscosity of the recycled concrete system is significantly increased after adding epoxy resin, and the bonding degree between the components is also improved. Epoxy resin promotes the adhesion of the components in the system. Epoxy resin can form a three-dimensional cross-linked structure with semiconductor waste and cement, making the connection between the systems tighter, thereby improving the strength of the recycled concrete. Hydroxyapatite has a porous structure that can store and release water, reducing the sensitivity of concrete workability to changes in the free water content in the concrete, allowing the free water content in the concrete to fluctuate within a certain range. At the same time, hydroxyapatite enhances the strength of epoxy resin, thus improving the strength of the concrete.

[0019] Preferably, the amount of hydroxyapatite added is 3-10% of the epoxy resin structural adhesive.

[0020] By adopting the above technical solution, as the amount of hydroxyapatite added increases, the compressive strength, tensile strength and shear strength of epoxy resin are continuously improved. However, when the amount of hydroxyapatite added is too high, the strength of epoxy resin decreases due to the easy agglomeration of hydroxyapatite.

[0021] Preferably, the hydroxyapatite is pre-treated with KH570 surface treatment.

[0022] By adopting the above technical solution, the surface treatment of hydroxyapatite helps to disperse in epoxy resin, increases the crosslinking density of epoxy resin, and thus improves the strength of epoxy resin.

[0023] Preferably, the additives include 0.5-1 parts by weight of polycarboxylic acid alkali water-reducing agent and 0.5-2 parts by weight of tourmaline powder activator.

[0024] Preferably, the tourmaline powder is one of lithium tourmaline powder, magnesium tourmaline powder, iron tourmaline powder, calcium magnesium tourmaline powder, calcium lithium tourmaline powder, or iron calcium magnesium tourmaline powder; more preferably, it is magnesium tourmaline powder.

[0025] By adopting the above technical solution, the polycarboxylic acid alkali water-reducing agent has a structural formula containing hydroxyl groups and ethers (-COC), which are hydrophilic. These groups combine with water molecules through hydrogen bonds to form a water film on the surface of cement particles. This water film has a good lubricating effect, which can effectively reduce the resistance between cement particles and increase the fluidity of concrete. However, the particle size of cement particles is at the micrometer level, while the polycarboxylic acid alkali molecules are at the nanometer level. Since the molecules of polycarboxylic acid alkali water-reducing agent are much smaller than cement particles, some of the polycarboxylic acid alkali water-reducing agent molecules will be partially or completely wrapped by cement particles, thus losing their water-reducing properties.

[0026] Tourmaline powder has thermoelectric properties. At a certain temperature, the charged particles in the crystal undergo relative displacement, the positive and negative charge centers separate, and the total electric moment of the crystal changes, resulting in the generation of polarization charge. The generation of this polarization charge can reduce the combination of the carboxyl end group of polycarboxylate superplasticizer with calcium ions in cement to a certain extent, promote the crystallization of calcium hydroxide, and thus improve the early strength performance.

[0027] In summary, the simultaneous addition of appropriate amounts of polycarboxylic acid alkali-reducing agent and tourmaline powder activator to recycled concrete made from semiconductor waste has a synergistic effect, improving the fluidity and early strength of the concrete.

[0028] Secondly, this application provides a method for preparing recycled concrete using semiconductor waste residue, employing the following technical solution:

[0029] A method for preparing recycled concrete using semiconductor waste includes the following steps: mixing the modified semiconductor waste, sand, cement, fly ash and mineral powder evenly to form a mixed solid material; then adding other raw materials to water, mixing evenly, and then adding them to the mixed solid material and mixing evenly.

[0030] By adopting the above technical solution, the modified semiconductor waste residue, sand, cement, fly ash and mineral powder are first mixed to facilitate uniform mixing. Then, other raw materials are dissolved in water and added to the solid mixture, which can improve the viscosity of concrete, enhance its fluidity and filling properties. The preparation method is efficient and convenient.

[0031] In summary, this application includes at least one of the following beneficial technical effects:

[0032] 1. This application uses semiconductor waste to form recycled concrete, which not only renders semiconductor waste harmless and makes it rationally utilized, but also improves the strength of the recycled concrete.

[0033] 2. This application treats semiconductors with alkali, making the semiconductor waste neutral and further improving the strength of concrete; 3. This application selects polycarboxylate superplasticizer and tourmaline powder activator as admixtures. Through the synergistic effect of polycarboxylate superplasticizer and tourmaline powder activator, the fluidity and early strength of recycled concrete are improved. Detailed Implementation

[0034] The following describes the application in further detail with preparation examples and embodiments.

[0035] Preparation Example

[0036] Preparation Example 1

[0037] This preparation example discloses a method for preparing modified semiconductor waste residue, the specific process of which is as follows:

[0038] Waste semiconductor materials are crushed and screened to obtain semiconductor waste residue with a particle size of 5-20 mm. 3 ml of 20 mol / L sodium hydroxide solution is added to 1 g of semiconductor waste residue. After reacting at 35 °C for 50 min, solid-liquid separation is performed. The residue is washed with water until neutral and filtered. Then, it is placed in an electric heating drying oven and dried to constant weight to obtain modified semiconductor waste residue.

[0039] Preparation Example 2

[0040] This preparation example discloses a method for preparing modified semiconductor waste residue, the specific process of which is as follows:

[0041] Waste semiconductor materials are crushed and screened to obtain semiconductor waste residue with a particle size of 5-20 mm. 12 ml of 15 mol / L sodium hydroxide solution is added to 1 g of semiconductor waste residue. After reacting at 30 °C for 60 min, solid-liquid separation is performed. The residue is washed with water until neutral and filtered. Then it is placed in an electric heating drying oven and dried to constant weight to obtain modified semiconductor waste residue.

[0042] Preparation Example 3

[0043] This preparation example discloses a method for preparing an adhesive, the specific process of which is as follows:

[0044] 100g of epoxy resin and 10g of reactive toughening diluent 660 were mixed and stirred in a mixer for 15 minutes to form an epoxy resin structural adhesive. 3g of hydroxyapatite was heat-treated at 650℃ for 1 hour, sieved through a 100-mesh sieve, and surface-treated with KH570 silane coupling agent to obtain modified hydroxyapatite. The modified hydroxyapatite was added to 100g of epoxy resin structural adhesive, poured into a colloid mill and ground for 30 minutes, then discharged and mixed with a curing agent, stirred for 10 minutes, and then degassed under vacuum to form an adhesive. The epoxy resin was E-51, purchased from Henan Yinghui Chemical Products Co., Ltd.; the reactive toughening diluent 660, whose main component is butyl glycidyl ether, has a viscosity (25℃) of 1.5-3.5 mPa·s; the hydroxyapatite was AS-20, purchased from Xi'an Zhanxun Biotechnology Co., Ltd.; and the KH570 silane coupling agent, containing amino groups, was purchased from Shandong Hengyu New Materials Co., Ltd.

[0045] Preparation Example 4

[0046] This preparation example discloses a method for preparing an adhesive, the specific process of which is as follows:

[0047] Mix 100g of epoxy resin and 10g of active toughening diluent 660 in a mixer for 15 minutes to form an epoxy resin structural adhesive; heat-treat 5g of hydroxyapatite at 650℃ for 1 hour, sieve through a 100-mesh sieve, and then surface-treat with KH570 silane coupling agent to obtain modified hydroxyapatite; add the modified hydroxyapatite to 100g of epoxy resin structural adhesive, pour into a colloid mill and grind for 30 minutes, then discharge the material, mix with the curing agent, stir for 10 minutes, and then degas under vacuum to form an adhesive.

[0048] Preparation Example 5

[0049] This preparation example discloses a method for preparing an adhesive, the specific process of which is as follows:

[0050] Mix 100g of epoxy resin and 10g of reactive toughening diluent 660 in a mixer for 15 minutes to form an epoxy resin structural adhesive; heat-treat 10g of hydroxyapatite at 650℃ for 1 hour, sieve through a 100-mesh sieve, and surface-treat with KH570 silane coupling agent to obtain modified hydroxyapatite; add the modified hydroxyapatite to 100g of epoxy resin structural adhesive, grind in a colloid mill for 30 minutes, discharge the material, mix with the curing agent, stir for 10 minutes, and then degas under vacuum to form an adhesive.

[0051] Example

[0052] Examples 1-13

[0053] As shown in Table 1, the difference between Examples 1-13 lies in the different raw material ratios of the recycled concrete made from semiconductor waste.

[0054] The following description uses Example 1 as an example. This application discloses a recycled concrete made from semiconductor waste, prepared using 90 kg of modified semiconductor waste, 70 kg of sand, 20 kg of cement, 10 kg of fly ash, 5 kg of mineral powder, 0.5 kg of polycarboxylic acid-based water-reducing agent, 0.5 kg of lithium tourmaline powder, and 15 kg of water as raw materials. The modified semiconductor waste is the one obtained in Example 1; the sand has a fineness of 2.3 and an apparent density of 2600 kg / m³. 3 The bulk density is 1500 kg / m³. 3 The cement is P.O425.5; the fly ash is Grade I fly ash, with a loss on ignition ≤3%, a 45μm sieve residue ≤10%, a water requirement ratio ≤95%, and a moisture content ≤1%; the mineral powder is Grade S95, with a specific surface area of ​​400m². 2 / Kg, 28d activity index is 95%, fluidity ratio is 95%; polycarboxylic acid alkali water-reducing agent model: 540P, purchased from Chongqing Haiyu Chemical Products Co., Ltd.; lithium tourmaline powder mesh size is 1250 mesh, purchased from Shijiazhuang Tomma Mineral Products Co., Ltd.

[0055] Table 1. Proportions of raw materials for recycled concrete made from semiconductor waste in Examples 1-13.

[0056]

[0057]

[0058] This application also discloses a method for preparing recycled concrete using semiconductor waste residue. The specific preparation process is as follows: Weigh modified semiconductor waste residue, sand, cement, fly ash and mineral powder according to the formula, stir evenly to make a mixed solid material, then add polycarboxylate water-reducing agent and lithium tourmaline powder to water, stir evenly and then add to the mixed solid material, and mix evenly.

[0059] Example 14

[0060] This embodiment is basically the same as Example 13, except that 3 kg of adhesive is added to the raw materials. The adhesive used is the one obtained in Preparation Example 3.

[0061] This application also discloses a method for preparing recycled concrete using semiconductor waste residue. The specific preparation process is as follows: Weigh modified semiconductor waste residue, sand, cement, fly ash and mineral powder according to the formula and mix them evenly to make a mixed solid material. Then add polycarboxylic acid alkali water-reducing agent, lithium tourmaline powder and binder to water, stir evenly and then add to the mixed solid material. Mix evenly.

[0062] Example 15

[0063] This embodiment is basically the same as Example 13, except that 3 kg of adhesive was added to the raw materials. The adhesive used was obtained from Preparation Example 4.

[0064] Example 16

[0065] This embodiment is basically the same as that of Example 13, except that 3 kg of adhesive is added to the raw materials. The adhesive used is the one obtained in Preparation Example 5.

[0066] Example 17

[0067] This embodiment is basically the same as Example 13, except that 6 kg of adhesive was added to the raw materials. The adhesive used was obtained from Preparation Example 4.

[0068] Example 18

[0069] This embodiment is basically the same as Example 13, except that 9 kg of adhesive was added to the raw materials. The adhesive used was obtained from Preparation Example 4.

[0070] Example 19

[0071] This embodiment is basically the same as Example 1, except that the modified semiconductor waste residue is the one obtained in Preparation Example 2.

[0072] Comparative Example

[0073] Comparative Example 1

[0074] The difference between this comparative example and Example 1 is that the semiconductor waste is not modified.

[0075] Comparative Example 2

[0076] The difference between this comparative example and Example 1 is that the modified semiconductor waste is replaced with concrete waste formed from crushed waste concrete.

[0077] Comparative Example 3

[0078] The difference between this comparative example and comparative example 14 is that the hydroxyapatite is not surface-treated when preparing the adhesive.

[0079] Comparative Example 4

[0080] The difference between this comparative example and comparative example 14 is that the amount of adhesive added is 15 kg.

[0081] Performance testing

[0082] The same weight of recycled concrete made from semiconductor waste obtained from Examples 1-19 was used as test samples 1-19, and the same weight of recycled concrete made from semiconductor waste obtained from Comparative Examples 1-4 was used as control samples 1-4. The performance of the test samples and control samples was tested, and the results are shown in Table 2.

[0083] The specific testing process is as follows: The recycled concrete made from semiconductor waste obtained from the test sample and the control sample were filled into the mold at one time. When filling, the mold was tamped along the wall of each mold with a trowel. Then the mold was placed on the vibration table and vibrated twice. The excess recycled concrete made from semiconductor waste was scraped off the mold opening. Then the mold was smoothed with a trowel and placed in a concrete curing box for curing for 24 hours. The mold was removed and the mold was finally moved to a standard concrete curing room for curing. After 28 days, the mold was taken out and the following tests were conducted.

[0084] Compressive strength and flexural strength: tested according to GB / T50107-2010 "Standard for Testing and Evaluation of Concrete Strength"; splitting tensile strength and flexural tensile strength: tested according to JTG 3420-2020 "Test Procedures for Cement and Cement Concrete in Highway Engineering".

[0085] Table 2 Performance test data of Examples 1-19 and Comparative Examples 1-4

[0086]

[0087]

[0088] Referring to Table 2, and in conjunction with Example 1 and Comparative Example 1, the strength of the recycled concrete obtained after modifying the semiconductor waste residue is significantly better than that of the recycled concrete obtained without modification of the semiconductor waste residue. Alkali treatment of the semiconductor waste residue neutralizes the hydrofluoric acid contained in the semiconductor, making the modified semiconductor generally neutral and improving the strength of the recycled concrete.

[0089] Referring to Table 2, and in conjunction with Example 1 and Comparative Example 2, it can be seen that replacing modified semiconductor waste with waste concrete waste results in a decrease in the strength of the recycled concrete. Waste concrete waste, due to its rough surface and high porosity, produces concrete with low strength after solidification. Using semiconductor waste in recycled concrete not only achieves the harmless treatment of toxic waste, making rational use of the semiconductor waste and generating economic benefits, but also, due to its inherent high strength, eliminates the need for external reinforcing agents to obtain high-strength recycled concrete.

[0090] Referring to Table 2 and in conjunction with Examples 1-3, it can be seen that as the content of modified semiconductor waste increases, the strength of the recycled concrete also increases. Semiconductor waste contains a large amount of silicon carbide, and silicon carbide has a very high hardness, thus improving the strength of the concrete.

[0091] Referring to Table 2, and in conjunction with Examples 2 and 4-13, it can be seen that by changing the contents of sand, cement, fly ash, mineral powder, polycarboxylic acid alkali-reducing agent, lithium tourmaline powder, and water in recycled concrete within an appropriate range, the prepared recycled concrete all exhibit good strength.

[0092] Referring to Table 2 and in conjunction with Examples 13 and 14, it can be seen that adding an adhesive to recycled concrete can improve the strength of the concrete. The epoxy resin in the adhesive increases the viscosity of the recycled concrete system, improving the bonding between components. Simultaneously, the epoxy resin forms a three-dimensional cross-linked structure with semiconductor waste and cement, making the system more tightly connected, thereby increasing the strength of the recycled concrete. Hydroxyapatite, with its porous structure allowing for water release and leaching, reduces the workability of the concrete and its sensitivity to changes in free water content, keeping the free water content within a suitable range. Furthermore, hydroxyapatite enhances the strength of the epoxy resin. Therefore, the adhesive obtained by modifying epoxy resin structural adhesive with hydroxyapatite can improve the strength of recycled concrete.

[0093] Referring to Table 2, and in conjunction with Example 14 and Comparative Example 3, it can be seen that the adhesive obtained by not modifying the surface of hydroxyapatite has a poorer effect on improving the strength of recycled concrete compared to the adhesive obtained by treating the surface of hydroxyapatite. Surface treatment of hydroxyapatite helps to improve its dispersion in epoxy resin, thereby increasing the crosslinking density of epoxy resin, which in turn improves the strength of epoxy resin and thus improves the overall strength of recycled concrete.

[0094] Referring to Table 2 and in conjunction with Examples 14-16, it can be seen that by changing the amount of hydroxyapatite added within an appropriate range, the resulting adhesives all improve the strength of recycled concrete. In particular, when the amount of hydroxyapatite added is 5% of the epoxy resin structural adhesive, the adhesive has the most significant effect on improving the strength of recycled concrete. This is because as the content of hydroxyapatite increases, the effect on enhancing the strength of epoxy resin becomes more significant. However, when excessive amounts of hydroxyapatite are added, due to its tendency to agglomerate, the strength of epoxy resin decreases, and thus the strength of the resulting recycled concrete decreases.

[0095] Referring to Table 2, and in conjunction with Examples 15, 17 and 18 and Comparative Example 4, varying the amount of adhesive added within an appropriate range can promote the strength of recycled concrete; however, when the amount of adhesive added is excessive, the strength of recycled concrete decreases instead.

[0096] Referring to Table 2, and in conjunction with Examples 1 and 19, by changing the solid-liquid ratio of the semiconductor waste to the alkali, the molar concentration of the alkali, and the temperature and time of the reaction within an appropriate range, the resulting recycled concrete made from the modified semiconductor waste exhibits high strength.

[0097] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A type of recycled concrete made from semiconductor waste, characterized in that: It is made from the following raw materials in parts by weight: 90-100 parts modified semiconductor waste residue, 70-80 parts sand, 20-30 parts cement, 10-20 parts fly ash, 5-10 parts mineral powder, 1-3 parts additives, and 15-20 parts water. It also includes 3-9 parts of an adhesive, which is obtained by modifying epoxy resin structural adhesive with hydroxyapatite; The hydroxyapatite was pre-treated with KH570 surface treatment; The modified semiconductor waste residue is obtained by modifying semiconductor waste residue with sodium hydroxide. The preparation method is as follows: the semiconductor waste residue and alkali are mixed and reacted; the solid-liquid ratio of the semiconductor waste residue to the alkali is 1:(3-4); the molar concentration of the alkali is 15-20 mol / L, the reaction temperature is 30-35℃, and the reaction time is 50-60 min. The admixtures include 0.5-1 parts by weight of polycarboxylate superplasticizer and 0.5-2 parts by weight of tourmaline powder activator; The particle size of the semiconductor waste residue is 5-20 mm.

2. The recycled concrete made from semiconductor waste as described in claim 1, characterized in that: The amount of hydroxyapatite added is 3-10% of the epoxy resin structural adhesive.

3. The recycled concrete made from semiconductor waste according to claim 1, characterized in that: The tourmaline powder is one of lithium tourmaline powder, magnesium tourmaline powder, iron tourmaline powder, calcium magnesium tourmaline powder, calcium lithium tourmaline powder, or iron calcium magnesium tourmaline powder.

4. A method for preparing recycled concrete using semiconductor waste as described in any one of claims 1-3, characterized in that: The modified semiconductor waste residue, sand, cement, fly ash and mineral powder are mixed evenly to form a mixed solid material. Then, other raw materials are added to water, stirred evenly, and then added to the mixed solid material and mixed evenly.

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