Method for preparing light thermal insulation material from modified phosphorous tailings

Abstract

The application discloses a method for preparing light thermal insulation material from modified phosphorite tailings. The phosphorite tailings are modified by certain means, then are uniformly mixed with cement, water reducing agent, coagulation accelerator and the like, then part of water is added and stirred to form uniform slurry A; meanwhile, a foaming agent and a collector are dissolved in water, foamed by a cement foaming machine and fully mixed with the slurry A to obtain the light thermal insulation material. The light thermal insulation material prepared from the phosphorite tailings has a bulk density of only 150-200 kg / m 3 , is non-combustible in grade A, has a normal-temperature thermal conductivity of less than or equal to 0.040 W / (m.K) and a water absorption of less than or equal to 25%. The material can provide a new idea for comprehensive utilization of the phosphorite tailings and support and guarantee for green and healthy development of phosphorus chemical industry.

Description

Technical Field

[0001] This invention relates to a method for preparing lightweight thermal insulation materials using modified phosphate tailings. The method involves modifying phosphate flotation tailings and adding suitable foaming agents and stabilizers to prepare building insulation materials, achieving efficient resource utilization. This method not only reduces production costs but also minimizes environmental pollution from tailings, aligning with the trend of green building and possessing broad market application prospects. The lightweight insulation materials prepared by this method, when applied to building exterior walls, can significantly reduce building operating energy consumption. Background Technology

[0002] Phosphate tailings are solid waste generated during the mineral processing stage of phosphate chemical production. Their accumulation not only occupies large amounts of land but also can lead to soil erosion and environmental pollution. Traditional treatment methods, such as landfilling, fail to effectively utilize resources. With increasingly stringent environmental protection requirements, there is an urgent need to develop efficient and environmentally friendly technologies for the comprehensive utilization of phosphate tailings.

[0003] Building energy consumption constitutes a major portion of total energy consumption, estimated to account for approximately 20% to 40% of the nation's total energy consumption. In building engineering, materials used to control heat loss from indoor spaces are called insulation materials, and these materials are crucial for reducing energy consumption. This invention modifies phosphate rock flotation tailings, utilizing the properties of calcium and magnesium elements in the tailings, and combines this with foam gel technology to prepare lightweight insulation materials. This solves both the tailings treatment problem and meets the energy-saving requirements of buildings. Summary of the Invention

[0004] This invention provides an innovative green building material using modified phosphate tailings as the main raw material. Through scientific formulation and fine processing, the prepared material possesses excellent thermal insulation properties. Experimental results show that its thermal conductivity is less than 0.040 W / (m·K), far lower than that of traditional insulation materials, effectively reducing heat exchange between the building's interior and exterior and improving energy efficiency. Furthermore, the material's density is only 150–200 kg / m³. 3 Its lightweight properties significantly reduce the load on buildings and provide greater flexibility for architectural design.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A method for preparing lightweight thermal insulation material from modified phosphate tailings, comprising the following raw materials: The composition of the flotation tailings is as follows: phosphate rock flotation tailings 25 wt%–40 wt%, sulfoaluminate cement 15 wt%–28 wt%, water-reducing agent 0.5 wt%–1.3 wt%, foaming agent 0.8 wt%–1.5 wt%, coagulant accelerator 0.1 wt%–1 wt%, calcium magnesium flotation collector 0.1 wt%–0.5 wt%, with water as the remainder.

[0007] As a preferred embodiment, the modified phosphorus tailings used to prepare lightweight thermal insulation material comprises the following raw materials: The modified phosphorus tailings are produced by two methods: one is mechanical activation modification by ultrafine grinding, which refers to grinding the phosphorus tailings to D90≥800 mesh; the other is tailings re-selection modification, which involves flotation to remove calcium and magnesium components and mud components, wherein the MgO grade is ≥20% and the CaO grade is ≥35%.

[0008] This invention also provides a method for preparing lightweight thermal insulation materials from modified phosphate tailings, comprising the following steps: (1) It is made by mixing the following components in a certain mass ratio, stirring them thoroughly with a specific foam, and then molding them: 25% to 40% modified phosphate rock flotation tailings, 15% to 28% sulfoaluminate cement, 0.5% to 1.3% water-reducing agent, 0.8% to 1.5% foaming agent, 0.1% to 1% coagulant, 0.1% to 0.5% calcium magnesium flotation collector, and 40% to 60% water.

[0009] The modified phosphorus tailings are produced by two methods: one is mechanical activation modification by ultrafine grinding, which refers to grinding the phosphorus tailings to D90≥800 mesh; the other is tailings re-selection modification, which involves flotation to remove calcium and magnesium components and mud components, wherein the MgO grade is ≥20% and the CaO grade is ≥35%.

[0010] (2) Add the modified phosphate rock flotation tailings, cement, water-reducing agent, and coagulant to water in sequence (water content 10% to 15%), and stir with a mixer for 3 to 5 minutes to form a uniform slurry A; In some specific implementations, the stirring time of slurry A is 3-4 minutes, the stirring speed is 200-400 r / min, and the mixture is stirred until it is a uniform gray color.

[0011] (3) Dissolve the foaming agent and collector in water (the remaining water) and foam it through a cement foaming machine to form a uniform and stable foam body B. The bubble height of foam body B is ≥200mm. (4) Mix the slurry A and foam B evenly with a mixer to obtain a lightweight thermal insulation material.

[0012] The water-reducing agent is a polycarboxylate water-reducing agent; the coagulant accelerator is one of lithium carbonate and alumina clinker.

[0013] The slurry A also contains anhydrous tetraurea gypsum, and the amount of anhydrous tetraurea gypsum added is 1-5% of the mass of the coagulant.

[0014] Tetraurene anhydrous gypsum is produced by a complexation reaction between calcium sulfate dihydrate (gypsum) and wet urea at room temperature.

[0015] The foaming agent is one or more of sodium dodecylbenzenesulfonate, modified saponins, and modified rosin soap.

[0016] The collector is one or more of MG-7 from Wuhan Wojuesheng Mining Technology Co., Ltd., and magnesium collectors BK-434 and BK-425 from Mining and Metallurgical Technology Group Co., Ltd.

[0017] In some embodiments, the slurry A and foam B are mixed and stirred for 3 to 5 minutes at a stirring speed of 400 to 600 r / min until a uniform gray foam is formed.

[0018] By adopting the above technical solution, the present invention has the following advantages compared with the prior art: (1) Utilize phosphorus tailings resources to achieve waste reuse, reduce environmental pollution, and improve resource utilization.

[0019] (2) Creatively using the reverse flotation reagent (collector) used in phosphate rock flotation as an additive, the phosphate tailings are effectively adsorbed onto the foam surface by utilizing the adsorption principle. Under the action of the coagulant, the phosphate tailings-foam gel system is rapidly solidified, achieving a lightweight effect.

[0020] (3) The lightweight thermal insulation material prepared by the present invention has a stable structure, strong durability, and is not easy to absorb water. It can be used in a variety of environments, which reduces the cost of building materials, is conducive to promoting green buildings, and promotes the sustainable development of the phosphorus chemical industry.

[0021] (4) The tetraurea anhydrous gypsum used in this invention is a biodegradable and environmentally friendly additive. It can not only provide the best foaming environment for the foaming agent, but also act as a foam stabilizer to prevent bubbles from rising and agglomerating, forming a uniform pore structure with a closed-cell rate of >90%, while reducing the thermal conductivity and optimizing the thermal insulation performance. Detailed Implementation

[0022] The following examples illustrate the invention further, but are not intended to limit the invention.

[0023] The calcium and magnesium flotation collectors described in this invention are modified fatty acid flotation collectors such as MG-7 (Wuhan Wojuesheng Mining Technology Co., Ltd.) and magnesium collectors BK-434 and BK-425 from Mining and Metallurgical Technology Group Co., Ltd.

[0024] The accelerators described in this invention are alumina clinker such as CN-1 (Laiyang Hongyang Building Admixture Factory), CN-2 (Dongying Hongfu Building Additive Factory), and FK-K (Shanxi Feike New Materials Co., Ltd.). Modified saponins and modified rosin soaps were purchased from Nantong Senfeng Special Building Materials Technology Co., Ltd.

[0025] The detection conditions described in this invention are as follows: Determination of bulk density GB / T 1033.1-2008; Determination of heat transfer coefficient GB / T 10294-2008; Water absorption rate determination GB / T 5480-2017; Flammability determination GB / T 5464-2010.

[0026] Example 1 (1) Mechanical activation and modification of phosphate tailings: ultrafine grinding was carried out by planetary ball mill, D 90 =12μm, to obtain modified phosphate tailings; (2) Ingredients: 30% modified phosphorus tailings, 20% sulfoaluminate cement, 1% polycarboxylate superplasticizer, 1% sodium dodecylbenzenesulfonate foaming agent, 0.1% lithium carbonate accelerator, 0.1% calcium magnesium flotation collector (MG-7), and the remainder is water; (3) Dissolve the water-reducing agent and the accelerator in 15% water. After fully dissolving, add the modified phosphorus tailings and sulfoaluminate cement in sequence and stir to form a uniform slurry A. The slurry A also contains 1% tetraurea anhydrous gypsum by mass of the accelerator. (4) Dissolve the foaming agent and collector in the remaining water, and form foam B using a foaming machine; (5) Mix slurry A and foam B evenly with a mixer, and after coagulation and molding, a lightweight thermal insulation material is obtained. Test the density, thermal conductivity, water absorption rate, and flammability. The test results show that the density is only 190 kg / m³. 3 It has a thermal conductivity of 0.038 W / (m·K), a water absorption rate of 18%, is Class A non-combustible, and fully complies with green building material standards.

[0027] Example 2 (1) Secondary flotation modification of phosphorus tailings: Using appropriate flotation reagent system and process, fine-grained materials and calcium-magnesium concentrate are flotated as modification raw materials. The MgO grade in the fine-grained materials and calcium-magnesium concentrate is ≥20%, and the CaO grade is ≥35%.

[0028] Ingredients: 25% modified phosphate tailings, 20% sulfoaluminate cement, 0.8% polycarboxylate superplasticizer, 0.8% modified saponin foaming agent, 0.1% coagulant CN-1, 0.1% calcium magnesium flotation collector (BK-425), and the remainder is water; (2) Dissolve the water-reducing agent and the accelerator in 10% water. After fully dissolving, add the modified phosphorus tailings and sulfoaluminate cement in sequence and stir to form a uniform slurry A. The slurry A also contains 1% tetraurea anhydrous gypsum by mass of the accelerator. (3) Dissolve the foaming agent and collector in the remaining water and form foam B using a foaming machine; (4) Mix slurry A and foam B evenly with a mixer, and after coagulation and molding, a lightweight thermal insulation material is obtained. Test the density, thermal conductivity, water absorption rate, and flammability. The test results show that the density is only 150 kg / m³. 3 It has a thermal conductivity of 0.035 W / (m·K), a water absorption rate of 19%, is Class A non-combustible, and meets the standards for green building materials.

[0029] Example 3 (1) Mechanical activation modification of phosphorus tailings: Ultrafine grinding was carried out using a planetary ball mill with D90=10μm to obtain modified phosphorus tailings; Ingredients: 30% modified phosphate tailings, 25% sulfoaluminate cement, 0.8% polycarboxylate superplasticizer, 1% sodium dodecylbenzenesulfonate, 0.2% lithium carbonate accelerator, and the remainder is water; (2) Dissolve polycarboxylate superplasticizer and lithium carbonate accelerator in 15% water. After fully dissolving, add phosphate tailings and aluminate cement in sequence and stir to form a uniform slurry A. (3) Dissolve sodium dodecylbenzenesulfonate in the remaining water and form foam B using a foaming machine; (4) Mix slurry A and foam B evenly with a mixer, and after coagulation and molding, a lightweight thermal insulation material is obtained. Test the density, thermal conductivity, water absorption rate, and flammability. The test results show that the density is 300 kg / m³. 3 It has a thermal conductivity of 0.16 W / (m·K), a water absorption rate of 30%, and is classified as Class A non-combustible.

[0030] Without the action of a collector, the calcium and magnesium components in the tailings cannot effectively adhere to the foam surface, cannot form an effective mineralized foam, the insulation material cannot be effectively formed, and delamination occurs, resulting in a significant reduction in insulation performance.

[0031] Example 4 (1) Use the original phosphorus tailings, that is, without using the modification process in this invention, the phosphorus tailings of the phosphorus chemical enterprise are dried and directly used in this comparative example; (2) Ingredients: 30% raw phosphorus tailings, 20% sulfoaluminate cement, 1% polycarboxylate superplasticizer, 1% sodium dodecylbenzenesulfonate foaming agent, 0.1% lithium carbonate accelerator, 0.1% calcium magnesium flotation collector (MG-7), and the remainder is water; (3) Dissolve the water-reducing agent and the accelerator in 15% water. After they are fully dissolved, add the modified phosphate tailings and aluminate cement in sequence and stir to form a uniform slurry A. (4) Dissolve the foaming agent and collector in the remaining water, and form foam B using a foaming machine; (5) Mix slurry A and foam B evenly with a mixer, and obtain a lightweight thermal insulation material after coagulation and molding. Test results show that the material cannot be effectively molded under this formula; a large amount of foam ruptures during the curing stage, and the bulk density is 400 kg / m³. 3 The insulation effect is poor.

[0032] Example 5 The same scheme as in Example 1 was used, but without the addition of tetraurea anhydrous gypsum. The bulk density was 268 kg / m³. 3 It has a thermal conductivity of 0.068 W / (m·K) and a water absorption rate of 25%, indicating poor material performance.

Claims

1. A method for preparing lightweight thermal insulation materials from modified phosphate tailings, characterized in that, Includes the following steps: (1) Add the phosphate rock flotation tailings, sulfoaluminate cement, water-reducing agent, and coagulant to a portion of water in sequence, and stir with a mixer for 3-5 minutes to form a uniform slurry A; (2) Dissolve the foaming agent and the collector in water and foam to form a uniform and stable foam body B; (3) Mix the slurry A and foam B evenly with a mixer to obtain a lightweight thermal insulation material.

2. The method according to claim 1, characterized in that, In step (1), the phosphate rock flotation tailings are subjected to ultrafine grinding, which means grinding the phosphate tailings to D90≥800 mesh.

3. The method according to claim 1, characterized in that, The stirring time for slurry A is 2-3 minutes, the stirring speed is 200-400 r / min, and the mixture is stirred until it is a uniform gray color.

4. The method according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent; the coagulant accelerator is one of lithium carbonate and alumina clinker.

5. The method according to claim 4, characterized in that, The slurry A also contains anhydrous tetraurea gypsum, and the amount of anhydrous tetraurea gypsum added is 1-5% of the mass of the coagulant.

6. The method according to claim 1, characterized in that, The foaming agent is one or more of sodium dodecylbenzenesulfonate, modified saponins, and modified rosin soap.

7. The method according to claim 1, characterized in that, The collector is one or more of MG-7, magnesium collector BK-434, and magnesium collector BK-425.

8. The method according to claim 1, characterized in that, In step (2), the bubble height of foam B is ≥200mm.

9. The method according to claim 1, characterized in that, The slurry A and foam B are mixed and stirred for 3 to 5 minutes at a stirring speed of 400 to 600 r / min until a uniform gray foam is formed.

10. The method according to claim 1, characterized in that, The composition of the flotation tailings is as follows: phosphate rock flotation tailings 25 wt%–40 wt%, sulfoaluminate cement 15 wt%–28 wt%, water-reducing agent 0.5 wt%–1.3 wt%, foaming agent 0.8 wt%–1.5 wt%, coagulant accelerator 0.1 wt%–1 wt%, calcium magnesium flotation collector 0.1 wt%–0.5 wt%, with the balance being water.