Solid waste salt curing material as well as preparation method and application thereof
By preparing a composite material containing solid waste salt, calcium sulfoaluminate binder, and crushed stone, the problem of resource utilization of solid waste salt is solved, realizing efficient and low-cost engineering applications, which are suitable for foundation reinforcement and railway subgrade.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 潍坊水动能科技产业研究院
- Filing Date
- 2024-11-04
- Publication Date
- 2026-05-08
AI Technical Summary
Existing technologies cannot effectively utilize solid waste salt, leading to resource waste and environmental pollution. Furthermore, the lack of comprehensive policies and regulations restricts the development of its resource utilization.
A curing material with fluidity and high strength is prepared by using solid waste salt, calcium sulfoaluminate binder, crushed stone, and materials such as accelerators, retarders, adsorbents, and water-reducing agents through mixing and curing. This material is used for engineering applications such as foundation reinforcement.
It realizes the resource utilization of solid waste salt, reduces engineering costs, improves engineering safety and material stability, and is applicable to foundation reinforcement, railway subgrade and mine backfilling.
Smart Images
Figure BDA0005115988970000061
Abstract
Description
[0001] This invention relates to a solid waste salt solidification material, its preparation method, and its application, belonging to the field of civil engineering materials. Background Technology
[0002] With the rapid development of China's chemical industry, a large amount of waste salt is generated during production. Solid waste salt includes by-product salt and high-salt residues produced during chemical production, as well as evaporated crystallized salt generated during the treatment of high-salt wastewater. Currently, this solid waste salt cannot be directly used as industrial raw material and can only be stockpiled or outsourced for disposal. This not only occupies a large amount of land but also incurs processing costs exceeding 3,000 yuan per ton, which is unbearable for enterprises. Furthermore, due to the lack of domestic waste salt disposal technology and related standards, the disposal rate and resource utilization rate of waste salt are extremely low, with most waste salt being rigidly landfilled. This situation not only threatens the environment but also wastes resources. Therefore, the development and reuse of solid waste salt has become a hot issue. From the perspective of my country's hazardous waste policy requirements and the development of the hazardous waste disposal and utilization industry, the treatment of solid waste salt will inevitably move towards comprehensive resource utilization.
[0003] Waste salt often contains large amounts of organic matter and heavy metals. The presence of these impurities is not only harmful to the environment but also increases the difficulty of resource utilization. Efficient and low-cost removal technologies need to be developed to ensure the safety and economic viability of waste salt resource utilization. However, each step requires significant investment of human, material, and financial resources. Furthermore, although industrial waste salt resource utilization has great potential, current policies and regulations are not yet comprehensive enough. There is a lack of clear waste salt treatment and emission standards, as well as corresponding policy support and incentives, which limits the development of waste salt resource utilization. Strengthening policy research and regulatory formulation is necessary to promote the sustainable development of industrial waste salt resource utilization.
[0004] The main technologies for the resource utilization of industrial waste salt include: incineration, high-temperature thermal melting, organic matter carbonization pyrolysis, advanced oxidation, wet catalytic oxidation, and hydrothermal oxidation. Through these technologies, the waste salt is rendered harmless and utilized as a resource. While these technologies have achieved certain results in practical applications, some challenges and limitations remain. It is necessary to strengthen research and development of low-cost, efficient, and environmentally friendly technologies for the resource utilization of industrial waste salt, as well as to establish a comprehensive policy and regulatory system to promote the resource utilization and environmental protection of industrial waste salt.
[0005] In summary, to overcome the problems of low efficiency, high cost, and inability to maximize resource utilization of new treatment technologies, solid waste salt samples were taken from coastal areas. Using the solid waste salt itself as aggregate, the physicochemical changes at different ages and dosages were studied. The aim is to provide a solidification method for solid waste salt, resulting in a structurally stable, long-term stable preventative effect, high strength, and environmentally friendly low-carbon self-leveling solid waste salt solidification material. This material can be widely used in foundation reinforcement, railway and highway subgrades, trench backfilling, and backfilling of mining subsidence areas. Summary of the Invention
[0006] To achieve comprehensive utilization of solid waste salt, this application provides a method for preparing solid waste salt solidification materials. The main materials are solid waste salt, calcium sulfoaluminate binder, and crushed stone, with accelerators, retarders, adsorbents, and water-reducing agents as secondary materials. A certain proportion of water is added and stirred to form a fluid building material that, after hardening, possesses a certain strength and long-term stability. This reduces solid waste salt pollution and also provides raw materials for the construction industry. By studying the relationship between the flexural and compressive strength, durability, and impermeability of the solidified waste salt and the amount and age of each material, a basis is provided for the design and construction of roadbeds in areas with solid waste salt.
[0007] Calcium sulfoaluminate binder is a hydraulic material based on calcium sulfoaluminate, made by directly calcining ultra-high strength cement clinker particles. It features rapid hardening, early strength, high strength, shrinkage compensation, self-drying, self-curing, and low-temperature construction. Used as a base material to solidify solid waste salts, it exhibits good mechanical and structural properties and high resistance to ultraviolet radiation and biodegradation. The use of crushed stone materials provides strong corrosion resistance, eliminating the need for independent roadbed protection measures and significantly reducing project costs. Accelerators and retarders control setting time, ensuring sufficient time for transport or pouring after mixing. Adsorbents effectively stabilize the treated waste salts, preventing them from reacting with components in the calcium sulfoaluminate binder to form calcium aluminum sulfate, which can cause volume expansion and cracking. They also adsorb heavy metals from the solid waste salts. Water-reducing agents alter the rheological behavior of the composite geosynthetic material, providing excellent self-leveling properties and solving problems such as limited pouring space and inability to backfill compaction. The resulting cementitious hydrates also result in a more uniform texture and higher strength.
[0008] To achieve the above objectives, the present invention provides the following technical solution:
[0009] This application provides a solid waste salt solidification material, which, by weight, is composed of the following raw materials: 63-100 parts solid waste salt, 30-40 parts calcium sulfoaluminate binder, 63-100 parts crushed stone, 0.4-0.6 parts coagulant, 0.7-0.9 parts retarder, 0.4-0.6 parts adsorbent, 0.4-0.6 parts water-reducing agent, and 9-12 parts water.
[0010] The solid waste salt is a solid waste with inorganic salts as its main components, namely sodium chloride and sodium sulfate. Before use, it is pretreated to remove impurities, heavy metals and organic matter.
[0011] The pretreatment refers to physical pretreatment and membrane separation pretreatment. Physical pretreatment removes impurities and solid particles from waste salt through physical methods such as screening, filtration, and precipitation. Membrane separation pretreatment uses membrane separation technology to separate impurities and harmful substances from waste salt.
[0012] The coagulant is water glass.
[0013] The retarder is citric acid.
[0014] The adsorbent is activated alumina, which is used to improve the quality of the solidified body.
[0015] The crushed stone material, by weight, is composed of the following raw materials: 50 to 80 parts of granite crushed stone and 13 to 20 parts of sand and gravel.
[0016] The particle size of the granite crushed stone is 10 mm to 50 mm, and the particle size of the sand and gravel is 20 mm to 30 mm.
[0017] Add 9-12 parts water. Too little water will not ensure sufficient hydration of the cement; too much water will cause bleeding.
[0018] This invention provides a method for preparing a solid waste salt solidification material, comprising the following steps:
[0019] (1) After crushing solid waste salt, mix it with calcium sulfoaluminate binder and crushed stone, add coagulant, retarder, adsorbent and water-reducing agent and mix, add water and stir to make slurry;
[0020] (2) The slurry was injected into the mold and cured at 23±1℃ and 99% humidity to prepare solid waste salt solidification material.
[0021] In step (1), the solid waste salt is crushed and the powder that can pass through an 80-mesh sieve is mixed with calcium sulfoaluminate binder and crushed stone.
[0022] The specific applications of solid waste salt solidification materials can be as follows:
[0023] After selecting solid waste salt within a depth range of 0-1.8m on the site, remove the solid waste salt and then compact and level the original ground surface. Crush the selected solid waste salt and mix it with calcium sulfoaluminate binder and crushed stone. Add accelerators, retarders, adsorbents, and water-reducing agents, mix well, and add water to form a slurry. Quickly backfill and compact the slurry in layers to level the ground surface. The specific steps are as follows:
[0024] (1) Take 63 to 100 samples of solid waste salt from the site and crush the waste salt into smaller particles for subsequent processing;
[0025] (2) Use a screening machine to remove impurities and solid particles from the crushed solid waste salt in step (1), and select powder that can pass through an 80-mesh sieve for later use.
[0026] (3) Take 30-40 parts of calcium sulfoaluminate binder, 63-100 parts of crushed stone, and 63-100 parts of solid waste salt screened in step (2), mix them evenly in a mixer to obtain mixed powder;
[0027] (4) Add 0.4 to 0.6 parts of coagulant, 0.7 to 0.9 parts of retarder, 0.4 to 0.6 parts of adsorbent, and 0.4 to 0.6 parts of water-reducing agent to the mixed powder, and then stir and mix for no less than 450 seconds to obtain the mixture;
[0028] (5) Add 9-12 parts of water to the mixture, stir quickly and evenly to prepare a slurry. If the expansion is ≥55cm after 30 minutes, the fluidity is good and it can be molded.
[0029] (6) Inject the slurry into the mold and cure it in the curing box at a temperature of 23±1℃ and a humidity of 99% to prepare solid waste salt solidification material.
[0030] The solidified waste salt of this invention has high compressive and flexural strength, and has shrinkage compensation properties, which can effectively prevent cracking. At the same time, it has a reasonable working time, which can meet the requirements of high-strength roadbeds. It can be widely used in foundation reinforcement, railway and highway roadbeds, trench backfilling, and mining goaf backfilling.
[0031] Compared with the prior art, the beneficial effects achieved by the present invention are:
[0032] (1) This invention uses solid waste salt itself as aggregate, which is different from the previous time-consuming and material-intensive soil replacement backfilling method. It not only turns waste into treasure, but also greatly saves costs, truly realizes the resource utilization of solid waste, reduces the use of high-energy-consuming calcium sulfoaluminate binder or cement, and is more economical and environmentally friendly.
[0033] (2) This invention prepares samples with different mixing ratios and studies the effects of age on the flexural and compressive strength and setting time of the cured material. Through intuitive analysis and scientific comparative analysis of the test results, the effects of different factors and different water-cement ratios on the solid waste salt cured material are obtained, and the optimal mixing ratio scheme is selected.
[0034] (3) This invention uses solid waste salt as aggregate to verify the suitability of the preliminary indoor experimental results of solid waste salt in actual engineering. The cost is extremely low, and it has completed a leap from theory to practice, laying the groundwork for rapid market launch.
[0035] (4) Solid waste salt contains soluble NaCl. In the composite design of this invention, chloride ions in the pore solution are consumed by physical adsorption and chemical bonding, thereby avoiding corrosion of steel bars and ensuring the safety of the project. Detailed Implementation
[0036] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.
[0037] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0038] As mentioned above, there is an urgent need to develop a cost-effective, environmentally friendly method for solidifying waste salts that facilitates maximum resource utilization. The invention will be further described below with reference to specific embodiments.
[0039] Example 1:
[0040] A solid waste salt solidification material, by mass parts, is composed of the following raw materials: 63 parts solid waste salt, 33 parts calcium sulfoaluminate binder, 63 parts crushed stone (granite crushed stone and sand), 0.4 parts coagulant, 0.7 parts retarder, 0.4 parts adsorbent, 0.4 parts water-reducing agent, and 11 parts water.
[0041] The preparation method of the above-mentioned solid waste salt solidification material specifically includes the following steps:
[0042] After crushing solid waste salt, it is mixed with calcium sulfoaluminate binder and crushed stone. Accelerator, retarder, adsorbent and water-reducing agent are added and mixed. Water is added and stirred at 150 r / min to make slurry. The slurry is poured into a mold with a size of 40mm×40mm×150mm. Three parallel samples are made for each group. After a batch of samples is prepared, they are immediately placed in a curing room at 23±1℃ and 99% humidity for curing. The initial setting time and final setting time, as well as the flexural and compressive strength at 1d, 3d and 7d are tested at the corresponding curing age. The appearance changes of the samples are observed, and whether there are cracks and erosion are observed.
[0043] Example 2:
[0044] A method for preparing a solid waste salt includes the following steps:
[0045] The mixture consisted of 63 parts solid waste salt, 33 parts calcium sulfoaluminate binder, 71 parts crushed stone (granite crushed stone and sand), 0.4 parts accelerator, 0.7 parts retarder, 0.4 parts adsorbent, and 11 parts water. The solid waste salt was crushed and mixed with the calcium sulfoaluminate binder and crushed stone. The accelerator, retarder, adsorbent, and water-reducing agent were added and mixed. Water was added and stirred at 150 rpm to form a slurry. The slurry was poured into molds measuring 40 mm × 40 mm × 150 mm, and three parallel samples were prepared for each batch. After a batch of samples was prepared, they were immediately placed in a curing room at 23 ± 1℃ and 99% humidity for curing. Initial and final setting times, as well as flexural and compressive strength at 1 day, 3 days, and 7 days, were tested at the corresponding curing ages. The appearance of the samples was observed, including the presence of cracks and erosion.
[0046] Example 3:
[0047] A method for preparing a solid waste salt includes the following steps:
[0048] The mixture consisted of 63 parts solid waste salt, 40 parts SAC (aluminum sulfoaluminate binder), 63 parts crushed stone (granite crushed stone and sand), 0.4 parts accelerator, 0.7 parts retarder, 0.4 parts adsorbent, 0.1 parts water-reducing agent, and 11 parts water. The solid waste salt was crushed and mixed with calcium sulfoaluminate binder and crushed stone. The accelerator, retarder, adsorbent, and water-reducing agent were added and mixed. Water was added and stirred at 150 rpm to form a slurry. The slurry was poured into molds measuring 40 mm × 40 mm × 150 mm, and three parallel samples were prepared for each batch. After a batch of samples was prepared, they were immediately placed in a curing room at 23 ± 1℃ and 99% humidity for curing. The initial and final setting times, as well as the flexural and compressive strength at 1 day, 3 days, and 7 days, were tested at the corresponding curing ages. The appearance of the samples was also observed, noting any cracks or erosion.
[0049] Example 4:
[0050] A method for preparing a solid waste salt includes the following steps:
[0051] The following materials were prepared: 90 parts solid waste salt, 100 parts SAC (aluminum sulfoaluminate binder), 100 parts crushed stone (granite crushed stone and sand), 0.4 parts accelerator, 0.7 parts retarder, 0.4 parts adsorbent, 0.4 parts water-reducing agent, and 11 parts water. The solid waste salt was crushed and mixed with calcium sulfoaluminate binder and crushed stone. The accelerator, retarder, adsorbent, and water-reducing agent were added and mixed. Water was added and stirred at 150 rpm to prepare a slurry. The slurry was poured into molds measuring 40 mm × 40 mm × 150 mm, and three parallel samples were prepared for each batch. After a batch of samples was prepared, they were immediately placed in a curing room at 23 ± 1℃ and 99% humidity for curing. The initial and final setting times, as well as the flexural and compressive strengths at 1 day, 3 days, and 7 days, were tested at the corresponding curing ages. The appearance of the samples was observed, including the presence of cracks and erosion.
[0052] Example 5:
[0053] A method for preparing a solid waste salt includes the following steps:
[0054] The mixture consisted of 85 parts solid waste salt, 70.8 parts SAC (calcium sulfoaluminate binder), 70.8 parts crushed stone (granite crushed stone and sand), 0.4 parts accelerator, 0.7 parts retarder, 0.4 parts adsorbent, 0.4 parts water-reducing agent, and 11 parts water. The solid waste salt was crushed and mixed with calcium sulfoaluminate binder and crushed stone. The accelerator, retarder, adsorbent, and water-reducing agent were added and mixed. Water was added and stirred at 150 rpm to form a slurry. The slurry was poured into molds measuring 40 mm × 40 mm × 150 mm, and three parallel samples were prepared for each batch. After a batch of samples was prepared, they were immediately placed in a curing room at 23 ± 1℃ and 99% humidity for curing. The initial and final setting times, as well as the flexural and compressive strength at 1 day, 3 days, and 7 days, were tested at the corresponding curing ages. The appearance of the samples was observed, including the presence of cracks and erosion.
[0055]
Claims
1. A solid waste salt solidification material, characterized in that, The product is composed of the following raw materials by weight: 63-100 parts solid waste salt, 30-40 parts calcium sulfoaluminate binder, 63-100 parts crushed stone, 0.4-0.6 parts coagulant, 0.7-0.9 parts retarder, 0.4-0.6 parts adsorbent, 0.4-0.6 parts water-reducing agent, and 9-12 parts water.
2. The solid waste salt solidification material according to claim 1, characterized in that, The solid waste salt is a solid waste product with inorganic salts as its main components, namely sodium chloride and sodium sulfate. It undergoes pretreatment before use to remove impurities, heavy metals, and organic matter.
3. The pretreatment according to claim 2 refers to physical pretreatment and membrane separation pretreatment. Physical pretreatment removes impurities and solid particles from waste salt through physical methods such as screening, filtration, and precipitation. Membrane separation pretreatment uses membrane separation technology to separate impurities and harmful substances from waste salt.
4. The solid waste salt solidification material according to claim 1, characterized in that, The coagulant is water glass, the retarder is citric acid, and the adsorbent is activated alumina.
5. A solid waste salt solidification material according to claim 1, characterized in that, The crushed stone material, by weight, is composed of the following raw materials: 50 to 80 parts of granite crushed stone and 13 to 20 parts of sand and gravel.
6. The solid waste salt solidification material according to claim 5, characterized in that, The particle size of the granite crushed stone is 10 mm to 50 mm, and the particle size of the sand and gravel is 20 mm to 30 mm.
7. Add 9-12 parts water. Too little water will not ensure sufficient hydration of the cement; too much water will cause bleeding.
8. A method for preparing a solid waste salt solidification material according to any one of claims 1-7, characterized in that, Includes the following steps: (1) After crushing solid waste salt, mix it with calcium sulfoaluminate binder and crushed stone, add coagulant, retarder, adsorbent and water-reducing agent and mix, add water and stir to make slurry; (2) The slurry was injected into the mold and cured at 23±1℃ and 99% humidity to prepare solid waste salt solidification material.
9. The method for preparing a solid waste salt solidification material according to claim 8, characterized in that, After crushing solid waste salt, the powder that can pass through an 80-mesh sieve is mixed with calcium sulfoaluminate binder and crushed stone.
10. The application of a solid waste salt solidification material according to any one of claims 1-7, characterized in that, After selecting solid waste salt within a depth range of 0-1.8m on the site, the solid waste salt is removed and the original ground is compacted and leveled. The selected solid waste salt is crushed and mixed with calcium sulfoaluminate binder and crushed stone. Accelerator, retarder, adsorbent and water-reducing agent are added and mixed. Water is added and stirred to make slurry. The slurry is quickly backfilled in layers onto the compacted and leveled original ground.