Mineral admixture suitable for phosphorus-based solid waste roadbed material and preparation method thereof

Abstract

The invention discloses a mineral admixture suitable for a phosphorus-based solid waste roadbed material and a preparation method thereof, the mineral admixture is prepared by taking carbide slag and Portland cement clinker as raw materials, spraying a small amount of additive on the surface of the raw materials, carrying out ball milling on the uniformly mixed materials in a ball mill for 25-30 minutes, and sieving with a 200-mesh sieve. The mineral admixture prepared by the invention can effectively solidify soluble phosphorus in the phosphorus-based solid waste roadbed material, stimulate the activity of phosphorus slag and generate C-S-H gel and AFt in a hydration process, so that the mechanical property and water resistance of the phosphorus-based solid waste roadbed material are remarkably improved. Besides, the mineral admixture takes the carbide slag as a main raw material, the preparation method is simple, the energy consumption is low, and the utilization of phosphatized industrial solid wastes in road engineering is promoted.

Description

Technical Field

[0001] The invention belongs to the field of building materials, and in particular relates to a mineral admixture suitable for phosphorus-based solid waste roadbed materials and a preparation method thereof. Background Art

[0002] Phosphogypsum is a solid waste produced by the industrial wet preparation of phosphoric acid and is one of the largest solid wastes discharged in the chemical industry. Due to the complex composition and unstable properties of phosphogypsum, it is difficult to achieve large-scale utilization. According to statistics, China's annual phosphogypsum discharge is about 75 million tons, and the stockpile reaches 400 million tons. However, the total utilization rate of phosphogypsum is only about 35%. Phosphate slag is a solid waste with calcium silicate as the main component produced in the process of thermal production of yellow phosphorus. Similar to slag, the glass content of phosphate slag can generally reach 85%~90%, and it has good potential hydration activity. According to statistics, China's annual phosphate slag discharge is about 7 million tons, while the total utilization rate of phosphate slag is less than 50%. The large-scale storage of phosphogypsum and phosphate slag not only occupies land resources, but also pollutes water resources. Whether phosphogypsum and phosphate slag can be used in large quantities directly determines the sustainable development of the phosphating industry. In this context, the comprehensive resource utilization of phosphogypsum and phosphate slag needs to be solved urgently.

[0003] Phosphorus-based solid waste roadbed materials composed of phosphogypsum and phosphate slag contain soluble impurities such as phosphorus and fluorine. The presence of these impurities will affect the normal hydration of building gypsum, change the crystal morphology of dihydrate gypsum, reduce the crystallization contact points of dihydrate gypsum, and reduce the mechanical properties. The activity of phosphate slag needs to be stimulated under alkaline conditions, and its hydration produces CSH gel and AFt, which can overlap with dihydrate gypsum crystals to improve the mechanical properties and water resistance of phosphorus-based solid waste roadbed materials. In response to the problem of poor mechanical properties and water resistance of phosphorus-based solid waste roadbed materials, this patent improves the above problems by adding mineral admixtures to phosphorus-based solid waste roadbed materials. Summary of the invention

[0004] The present invention provides a mineral admixture suitable for phosphorus-based solid waste roadbed materials. The invention adopts carbide slag and silicate cement clinker as the matrix, and a small amount of admixture is added to modify the phosphorus-based solid waste roadbed materials. The carbide slag can react with the soluble phosphorus in the phosphorus-based solid waste roadbed materials to generate Ca3(PO4)2 precipitation, which effectively solidifies the impurities in the phosphorus-based solid waste roadbed materials and prevents them from affecting the hydration of building gypsum and silicate cement clinker. The addition of admixtures is not only conducive to the grinding of carbide slag and silicate cement clinker, but also can promote the dissolution of aluminum phase and iron phase in silicate cement clinker, so that AFt is generated in the early stage of hydration, which has a certain improvement effect on the early strength and water resistance of the composite system. In addition, under the alkaline excitation of carbide slag and silicate cement clinker, the phosphate slag generates CSH gel and AFt in the middle and late stages of hydration, so that the mechanical properties and water resistance of the phosphorus-based solid waste roadbed materials are further improved.

[0005] In order to achieve the above technical objectives, the present invention provides the following technical solutions: A mineral admixture suitable for phosphorus-based solid waste roadbed materials comprises the following steps: 1) Weigh 0.3-0.5 parts by weight of the additive and dissolve it in 5 parts by weight of deionized water. Use a magnetic stirrer to stir rapidly to promote its rapid dissolution; 2) Mix carbide slag and Portland cement clinker in a mass ratio of 80-60:20-40 to prepare 100 parts by weight of material; 3) The solution obtained in step 1) is uniformly sprayed on the surface of the material obtained in step 2) by spraying, and then ball milled in a ball mill for 25-30 minutes; 4) The ball-milled material is passed through a 200-mesh sieve to prepare a mineral admixture suitable for phosphorus-based solid waste roadbed materials; 5) A mineral admixture suitable for phosphorus-based solid waste roadbed materials is prepared, and its admixture amount is 10-30% of the total amount of cementitious materials.

[0006] In the above scheme, the phosphorus-based solid waste roadbed material is composed of phosphogypsum and phosphorus slag in a mass ratio of 90-80:10-20; In the above scheme, the preparation method of the phosphogypsum is as follows: the original phosphogypsum is ball-milled in a ball mill for 25-30 minutes, passed through a 100-mesh sieve, and then calcined in an oven at a calcination temperature of 150° C. for 5 hours, and aged in air for 3 days to obtain phosphogypsum powder with an average particle size of 36-38 μm; In the above scheme, the preparation method of the phosphate slag is as follows: the phosphate slag is ball-milled in a ball mill for 45-50 minutes, and then passed through a 200-mesh sieve to obtain phosphate slag with an average particle size of 8-10 um; In the above scheme, the admixture is one or more of triisopropanolamine, triethanolamine, and polyethylene glycol; In the above scheme, the triisopropanolamine has a purity of 95%, a molecular formula of [CH3CH(OH)CH2]3N, and a molecular weight of 191; In the above scheme, the purity of triethanolamine is 99%, and the molecular formula is C6H 15 NO3, molecular weight 149; In the above scheme, the polyethylene glycol has a purity of 99% and a molecular formula of HO(CH2CH2O) n H, molecular weight 44; In the above scheme, the material needs to be crushed by a jaw crusher to a particle size of less than 7mm before entering the mill; Compared with the prior art, the present invention has the following advantages and beneficial effects: (1) The admixture used in the present invention is beneficial to the grinding of carbide slag and silicate cement clinker, and can also promote the dissolution of aluminum phase and iron phase in silicate cement clinker, so that silicate cement clinker generates AFt in the early stage of hydration, which has a certain effect on improving the early strength of phosphorus-based solid waste roadbed materials; (2) In the present invention, carbide slag and silicate cement clinker are used as the matrix. The carbide slag can react with the soluble phosphorus in the phosphorus-based solid waste roadbed material to generate Ca3(PO4)2 precipitation, effectively solidifying the impurities in the phosphorus-based solid waste roadbed material, preventing them from affecting the hydration of phosphogypsum and silicate cement clinker, and having a certain improvement effect on the early strength and water resistance of the phosphorus-based solid waste roadbed material. At the same time, under the alkaline excitation of carbide slag and silicate cement clinker, the phosphate slag generates CSH gel and a small amount of AFt in the middle and late stages of hydration, further improving the mechanical properties and water resistance; (3) The mineral admixture obtained by the present invention is used for phosphorus-based solid waste roadbed materials, so that the phosphorus-based solid waste roadbed materials form a relatively dense microstructure, effectively improve their compressive strength and softening coefficient, and help promote the high added value utilization of solid waste from the phosphating industry in engineering, with good economic benefits, environmental benefits and social benefits. Implementation

[0007] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with specific embodiments, but the content of the present invention is not limited to the following embodiments. Example

[0008] A mineral admixture suitable for phosphorus-based solid waste roadbed materials and a preparation method thereof, comprising the following steps: 1) Weigh 0.3 parts by weight of triisopropanolamine and dissolve it in 5 parts by weight of deionized water, and use a magnetic stirrer to stir rapidly to promote its rapid dissolution; 2) Mix carbide slag and Portland cement clinker in a mass ratio of 80:20 to prepare 100 parts by weight of material; 3) The solution obtained in step 1) is uniformly sprayed on the surface of the material obtained in step 2) by spraying, and then ball milled in a ball mill for 25-30 minutes; 4) The ball-milled material is passed through a 200-mesh sieve to prepare a mineral admixture suitable for phosphorus-based solid waste roadbed materials; 5) A mineral admixture suitable for phosphorus-based solid waste roadbed materials is prepared, and its admixture amount is 10-30% of the total amount of cementitious materials. Example

[0009] A mineral admixture suitable for phosphorus-based solid waste roadbed materials and a preparation method thereof, comprising the following steps: 1) Weigh 0.4 parts by weight of triethanolamine and dissolve it in 5 parts by weight of deionized water. Use a magnetic stirrer to stir rapidly to promote its rapid dissolution; 2) Mix carbide slag and Portland cement clinker in a mass ratio of 70:30 to prepare 100 parts by weight of material; 3) The solution obtained in step 1) is uniformly sprayed on the surface of the material obtained in step 2) by spraying, and then ball milled in a ball mill for 25-30 minutes; 4) The ball-milled material is passed through a 200-mesh sieve to prepare a mineral admixture suitable for phosphorus-based solid waste roadbed materials; 5) A mineral admixture suitable for phosphorus-based solid waste roadbed materials is prepared, and its admixture amount is 10-30% of the total amount of cementitious materials. Example

[0010] A mineral admixture suitable for phosphorus-based solid waste roadbed materials and a preparation method thereof, comprising the following steps: 1) Weigh 0.5 parts by weight of polyethylene glycol and dissolve it in 5 parts by weight of deionized water. Use a magnetic stirrer to stir rapidly to promote its rapid dissolution. 2) Mix carbide slag and Portland cement clinker in a mass ratio of 60:40 to prepare 100 parts by weight of material; 3) The solution obtained in step 1) is uniformly sprayed on the surface of the material obtained in step 2) by spraying, and then ball milled in a ball mill for 25-30 minutes; 4) The ball-milled material is passed through a 200-mesh sieve to prepare a mineral admixture suitable for phosphorus-based solid waste roadbed materials; 5) A mineral admixture suitable for phosphorus-based solid waste roadbed materials is prepared, and its admixture amount is 10-30% of the total amount of cementitious materials.

[0011] The mineral admixtures obtained in Examples 1 to 3 were applied to the phosphorus-based solid waste roadbed material system, wherein the phosphorus-based solid waste roadbed material was prepared according to the formula described in Table 1 (the fixed water-binder ratio in the phosphorus-based solid waste roadbed material slurry was 0.4, and the standard consistency was adjusted by changing the amount of polycarboxylate water-reducing agent). The compressive strength of the sample was tested according to the experimental method in GB / T 17669.3-1999, and the softening coefficient of the sample was tested according to the experimental method in JC / T 698-2010. The compressive strength and softening coefficient of the sample without adding mineral admixture (blank group) and with different mineral admixtures were compared, and the test results are shown in Table 2.

[0012] Table 1 Phosphogypsum Phosphate slag Example 1 Example 2 Example 3 water Blank Group 270 30 120 Application Example 1 243 27 30 120 Application Example 2 216 24 60 120 Application Example 3 189 21 90 120 Application Example 4 243 27 30 120 Application Example 5 216 24 60 120 Application Example 6 189 21 90 120 Application Example 7 243 27 30 120 Application Example 8 216 24 60 120 Application Example 9 189 21 90 120 Table 2 1d strength / MPa 7d strength / MPa 28d strength / MPa Softening coefficient Blank Group 9.3 11.2 11.5 0.32 Application Example 1 11.9 14.4 17.6 0.49 Application Example 2 12.5 15.5 19.1 0.56 Application Example 3 12.3 15.0 18.5 0.55 Application Example 4 10.3 13.2 16.9 0.48 Application Example 5 11.0 14.4 18.0 0.52 Application Example 6 10.7 14.0 17.2 0.49 Application Example 7 10.2 14.8 16.2 0.46 Application Example 8 10.9 15.5 17.7 0.49 Application Example 9 10.5 14.8 16.0 0.45 The above results show that: compared with the blank group, after adding the mineral admixtures prepared in Example 1, Example 2 and Example 3, the early strength and late strength of the obtained phosphorus-based solid waste roadbed material are significantly improved. In addition, its water resistance is also improved to a certain extent, effectively solving the problem of poor mechanical properties and water resistance of phosphorus-based solid waste roadbed materials. This patent broadens the utilization field of solid waste from the phosphating industry, provides a reference for the high added value utilization of solid waste from the phosphating industry, and has certain practical significance.

Claims

1. A mineral admixture suitable for phosphorus-based solid waste roadbed materials and a preparation method thereof, which is prepared by the following components, and the process is as follows: 1) Weigh 0.3-0.5 parts by weight of the additive and dissolve it in 5 parts by weight of deionized water. Use a magnetic stirrer to stir rapidly to promote its rapid dissolution; 2) Mix carbide slag and Portland cement clinker in a mass ratio of 80-60:20-40 to prepare 100 parts by weight of material; 3) The solution obtained in step 1) is uniformly sprayed on the surface of the material obtained in step 2) by spraying, and then ball milled in a ball mill for 25-30 minutes; 4) The ball-milled material is passed through a 200-mesh sieve to prepare a mineral admixture suitable for phosphorus-based solid waste roadbed materials; 5) A mineral admixture suitable for phosphorus-based solid waste roadbed materials is prepared, and its admixture amount is 10-30% of the total amount of cementitious materials.

2. The mineral admixture suitable for phosphorus-based solid waste roadbed materials and the preparation method thereof according to claim 1, characterized in that: The phosphorus-based solid waste roadbed material is composed of phosphogypsum and phosphorus slag in a mass ratio of 90-80:10-20.

3. The phosphorus-based solid waste roadbed material according to claims 1-2, characterized in that: The preparation method of the phosphogypsum is as follows: the original phosphogypsum is ball-milled in a ball mill for 25-30 minutes, passed through a 100-mesh sieve, and then calcined in an oven at a calcination temperature of 150° C. for 5 hours, and aged in air for 3 days to obtain phosphogypsum with an average particle size of 36-38 μm.

4. The phosphorus-based solid waste roadbed material according to claims 1-2, characterized in that: The preparation method of the phosphate slag is as follows: the original phosphate slag is ball-milled in a ball mill for 45-50 minutes, and the phosphate slag is passed through a 200-mesh sieve to obtain the phosphate slag with an average particle size of 8-10 um.

5. The mineral admixture suitable for phosphorus-based solid waste roadbed materials and the preparation method thereof according to claim 1, characterized in that: The additive is one or more of triisopropanolamine, triethanolamine and polyethylene glycol.

6. The admixture according to claim 5, characterized in that The triisopropanolamine has a purity of 95%, a molecular formula of [CH3CH(OH)CH2]3N, and a molecular weight of 191.

7. The admixture according to claim 5, characterized in that The purity of triethanolamine is 99%, and its molecular formula is C6H 15 NO3, molecular weight is 149.

8. The admixture according to claim 5, characterized in that The purity of the polyethylene glycol is 99%, and the molecular formula is HO(CH2CH2O) n H, molecular weight is 44.

9. The mineral admixture suitable for phosphorus-based solid waste roadbed materials and the preparation method thereof according to claim 1, characterized in that: The uniformly mixed material in step 2) of claim 1 needs to be crushed by a jaw crusher to a particle size of less than 7 mm before entering the mill.