An asphalt anti-stripping agent for tailings aggregate and a preparation method thereof

Abstract

The application discloses an asphalt anti-stripping agent for tailing aggregate and a preparation method thereof, and the asphalt anti-stripping agent comprises the following components in percentage by mass: tailing powder 55-65%, lime powder 30-40%, fatty alcohol polyoxyethylene ether phosphate 3-4% and silane coupling agent 1-2%. The preparation method is as follows: (1) mixing fatty alcohol polyoxyethylene ether phosphate and silane coupling agent according to a mass ratio of 2:1, stirring uniformly to obtain a premade mixed solution; (2) drying iron tailing slag, grinding to a passing rate of 85-100% of <0.075 mm, and then mixing with lime powder uniformly to obtain a premade mixed powder; and (3) uniformly spraying the premade mixed solution in (1) on the mixed powder in step (2), and the ratio of the mixed solution to the mixed powder is 1:(10-15), and then drying to obtain the asphalt anti-stripping agent. The asphalt anti-stripping agent can improve the adhesion of asphalt and tailing aggregate, improve the water stability of the mixture, and promote the application of tailing aggregate in road engineering.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of asphalt additives, in particular to an asphalt anti-stripping agent for tailings aggregate and a preparation method thereof. BACKGROUND

[0002] The large accumulation of tailings is prone to cause geological disasters, environmental pollution and waste of land resources. In recent years, the comprehensive utilization of tailings has been increasing, but it has not formed large-scale application. Using tailings as a kind of aggregate replacement material applied to high-grade asphalt concrete pavement material can not only improve the comprehensive utilization value of iron tailings, but also greatly reduce the construction cost of asphalt pavement.

[0003] Compared with conventional aggregate, the physical and mechanical properties of tailings aggregate meet the specification requirements of aggregate, but iron tailings belong to high-silicon stone, which has poor adhesion with asphalt, and is prone to cause water damage such as loose pavement, rough surface, pit and groove, and pumping. The key to water damage is the insufficient adhesion between asphalt and aggregate, which causes the asphalt film to fall off from the surface of the aggregate. Therefore, in order to use tailings aggregate and prevent the occurrence of water damage, it is crucial to improve the adhesion between asphalt and aggregate, and the simplest and most effective method is to add an anti-stripping agent. However, there is no anti-stripping agent specially for tailings aggregate, and most of the commonly used anti-stripping agents are amine compounds, which have poor thermal stability and are prone to performance failure when directly acting on asphalt.

[0004] CN102174264A discloses a road asphalt anti-stripping agent and a preparation method thereof. The method comprises the following components: 50-65 parts of polyethylene glycol; 10-30 parts of alkoxy aliphatic polyamine; 5-15 parts of alkyl amine; 5-15 parts of polyamine; 1-2 parts of alcohol ether compound; and 13-29 parts of diethanolamine. However, the aliphatic amine anti-stripping agent has poor thermal stability and is mainly based on physical adsorption, which limits the use of amine anti-stripping agent.

[0005] CN108623207A discloses an asphalt anti-stripping agent containing phosphate ester salt and a use method thereof. The composition comprises sodium dodecyl phosphate and octadecyl trimethyl ammonium chloride. When used, the anti-stripping agent needs to be mixed uniformly with hot asphalt, and the aggregate is not modified, which can lead to limited anti-stripping effect due to uneven dispersion when the addition amount is small.

[0006] In summary, it is of great social and economic significance to develop an asphalt anti-stripping agent for tailings aggregate with good thermal stability and significant adhesion improvement, and to comprehensively utilize iron ore solid waste. SUMMARY

[0007] In view of the deficiencies of the prior art, the present application aims to provide an asphalt anti-stripping agent for tailings aggregate and a preparation method thereof.The asphalt anti-stripping agent prepared by the method can improve the adhesion between the tailings aggregate and the asphalt and improve the water stability of the tailings asphalt mixture.

[0008] The present application provides an asphalt anti-stripping agent for tailings aggregate, comprising the following components in mass percentage:

[0009] Tailings powder 55% to 65%

[0010] Lime powder 30% to 40%

[0011] Fatty alcohol polyoxyethylene ether phosphate 3% to 4%

[0012] Silane coupling agent 1% to 2%.

[0013] The tailings powder has the following chemical components: 55% to 60% of SiO2, 10% to 18% of Fe2O3, 10% to 15% of Al2O3, and 6% to 10% of CaO, and the particle size requirement is that the passing rate of a standard square hole sieve of <0.075 mm is 85% to 100%, and the tailings powder is generally the iron tailings powder after magnetic separation in a mining area.

[0014] The lime powder is an industrial-grade lime powder, and the content of Ca(OH)2 is greater than 90% by weight, and the particle size is 80-500 mesh.

[0015] The fatty alcohol polyoxyethylene ether phosphate AEO-P has the general formula RO(CH2CH2O)nPO3H2, wherein the fatty alcohol ROH includes one or more of C8-18 alcohol, isooctanol, lauryl alcohol, isodecanol, and cetyl alcohol, and the addition number n of ethylene oxide (CH2CH2O) is 3-9.

[0016] The silane coupling agent is one or more of vinyltriethoxysilane, gamma-aminopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-glycidyl ether propyl trimethyl silane, and gamma-methacryloyloxypropyltrimethoxysilane.

[0017] The present application provides a preparation method of the asphalt anti-stripping agent for tailings aggregate, comprising the following steps:

[0018] (1) uniformly mix the fatty alcohol polyoxyethylene ether phosphate and the silane coupling agent to obtain a pre-prepared mixed solution;

[0019] (2) dry the iron tailings slag, grind it to a passing rate of 85% to 100% of <0.075 mm, and uniformly mix the lime powder to obtain a pre-prepared mixed powder;

[0020] (3) evenly spraying the pre-prepared mixed solution in (1) on the mixed powder in step (2), and drying to obtain the asphalt mixture anti-stripping agent.

[0021] In the method, in step (1), the preparation method of the fatty alcohol polyoxyethylene ether phosphate is as follows: under nitrogen protection, two portions of fatty alcohol polyoxyethylene ether AEO are added, one portion of P2O5 is added in batches under stirring, and the temperature is increased for continuous stirring, and the fatty alcohol polyoxyethylene ether phosphate is obtained after hydrolysis, wherein the P2O5 addition time in batches is 1.5-2 h, the heating temperature is 80-90 DEG C, and the stirring time is 4 h.

[0022] In the method, in step (2), the proportion of the mixed powder is 55%-65% tailing powder and 30%-40% lime powder.

[0023] In the method, in step (3), the drying temperature is 100-105 DEG C, and the drying time is 2-3 h.

[0024] The use method of the asphalt mixture anti-stripping agent comprises the following steps: the asphalt mixture anti-stripping agent is mixed into the mineral powder of the tailing aggregate asphalt mixture, wherein the replacement mineral powder mixing amount is greater than or equal to 80 wt%, the coarse aggregate and the fine aggregate in the tailing aggregate asphalt mixture are both iron mine waste rocks, and the mineral powder is a magnetic separation tailing powder.

[0025] Compared with the prior art, the present application has the following characteristics:

[0026] (1) The asphalt anti-stripping agent of the present application has a dual effect, one is that the mixing of the lime powder component can not only improve the acidic environment of the aggregate surface due to its strong alkalinity and high chemical adsorption energy, but also has a larger specific surface area and more sufficient adsorption of asphalt, and the other is that the fatty alcohol polyoxyethylene ether phosphate and the silane coupling agent have different functional groups at both ends, one end is hydrogen-bonded to the hydroxyl group on the surface of the aggregate, and the other end is entangled and crosslinked with the asphalt macromolecule, so that the overall adhesion of the asphalt mixture is strengthened.

[0027] (2) The tailing asphalt mixture obtained by using the asphalt anti-stripping agent of the present application not only significantly enhances the water stability, high-temperature stability and low-temperature crack resistance, but also improves the road performance of the mixture, and all the road performances meet the use index requirements of the road surface in the Technical Specification for Highway Asphalt Pavement Construction (JTG F40-2004), promotes the comprehensive utilization of tailing solid waste, and provides a good foundation for the subsequent application of tailing asphalt mixture. DETAILED DESCRIPTION

[0028] In order to better understand the present application, the preparation method of the asphalt anti-stripping agent for tailing aggregate provided by the present application will be further described below by means of examples, but the following examples do not constitute a limitation on the present application.

[0029] Example 1

[0030] The raw materials were weighed by mass fraction, the fatty alcohol polyoxyethylene ether phosphate and the silane coupling agent were mixed in a mass ratio of 2:1, stirred uniformly to obtain a pre-mixed liquid. The iron tailings slag was dried and ground to a passing rate of <0.075 mm of 85~100%, and the lime powder was added in a mass ratio of 55:40 to mix uniformly to obtain a pre-mixed powder. The pre-mixed liquid was uniformly sprayed on the mixed powder, the ratio of the mixed liquid to the mixed powder was 1:10, and the asphalt mixture anti-stripping agent A1 was obtained by drying at 100~105℃ for 2~3h.

[0031] Example 2

[0032] The raw materials were weighed by mass fraction, the fatty alcohol polyoxyethylene ether phosphate and the silane coupling agent were mixed in a mass ratio of 2:1, stirred uniformly to obtain a pre-mixed liquid. The iron tailings slag was dried and ground to a passing rate of <0.075 mm of 85~100%, and the lime powder was added in a mass ratio of 55:40 to mix uniformly to obtain a pre-mixed powder. The pre-mixed liquid was uniformly sprayed on the mixed powder, the ratio of the mixed liquid to the mixed powder was 1:12, and the asphalt mixture anti-stripping agent A2 was obtained by drying at 100~105℃ for 2~3h.

[0033] Example 3

[0034] The raw materials were weighed by mass fraction, the fatty alcohol polyoxyethylene ether phosphate and the silane coupling agent were mixed in a mass ratio of 2:1, stirred uniformly to obtain a pre-mixed liquid. The iron tailings slag was dried and ground to a passing rate of <0.075 mm of 85~100%, and the lime powder was added in a mass ratio of 55:40 to mix uniformly to obtain a pre-mixed powder. The pre-mixed liquid was uniformly sprayed on the mixed powder, the ratio of the mixed liquid to the mixed powder was 1:15, and the asphalt mixture anti-stripping agent A3 was obtained by drying at 100~105℃ for 2~3h.

[0035] Comparative Example 1

[0036] The raw materials were weighed by mass fraction, the fatty alcohol polyoxyethylene ether phosphate and the silane coupling agent were mixed in a mass ratio of 2:1, stirred uniformly to obtain a pre-mixed liquid. The iron tailings slag was dried and ground to a passing rate of <0.075 mm of 85~100%, and the lime powder was added in a mass ratio of 55:40 to mix uniformly to obtain a pre-mixed powder. The pre-mixed liquid was uniformly sprayed on the mixed powder, the ratio of the mixed liquid to the mixed powder was 1:10, and the asphalt mixture anti-stripping agent B1 was obtained by drying at 100~105℃ for 2~3h.

[0037] Comparative Example 2

[0038] The raw materials were weighed by mass fraction, the iron tailings slag was dried and ground to a passing rate of 85-100% of <0.075 mm, and lime powder was added in a ratio of 3:2 to mix evenly to obtain a pre-prepared mixed powder, and an asphalt mixture anti-stripping agent B2 was obtained.

[0039] Comparative Example 3

[0040] An amine asphalt anti-stripping agent commonly used in asphalt pavement construction, namely, Calloamine, was selected, and the Calloamine additive was used as an asphalt mixture anti-stripping agent B3, which was added into the tailings asphalt mixture at a proportion of 0.5% of the base asphalt content.

[0041] Comparative Example 4

[0042] The raw materials were weighed by mass fraction, the iron tailings slag was dried and ground to a passing rate of 85-100% of <0.075 mm, and lime powder was added in a ratio of 3:2 to mix evenly to obtain a pre-prepared mixed powder, and an asphalt mixture anti-stripping agent B2 was obtained.

[0043] According to the use method, the asphalt mixture anti-stripping agents of Examples 1-3 and Comparative Examples 1-2 were added into the mineral powder of the tailings aggregate asphalt mixture at a replacement amount of 80 wt%, Comparative Example 3 was added into the base asphalt, and the components one and two of Comparative Example 4 were added into the base asphalt and the mineral powder of the asphalt mixture, respectively, and then the asphalt mixture was prepared. The coarse aggregate and fine aggregate in the iron tailings aggregate asphalt mixture were both iron mine waste stones, the mineral powder was tailings powder, the base asphalt was Qilu 70A asphalt, and the asphalt mixture gradation type was AC-20. The road performance of the asphalt mixture was evaluated.

[0044] The road performance of the asphalt mixture was carried out according to (JTG E20-2011) “Highway Engineering Asphalt and Asphalt Mixture Test Procedures”, wherein the water stability was investigated by the immersion residual stability MS0 of the immersion Marshall test (T 0709-2011) and the freeze-thaw splitting strength ratio TSR of the freeze-thaw splitting test (T 0729-2000), the high-temperature stability was investigated by the dynamic stability of the rutting test (T 0719-2011), and the low-temperature crack resistance was investigated by the bending tensile strength and maximum bending tensile strain of the low-temperature bending test (T 0715-2011). The results are shown in Table 1.

[0045] Table 1 Performance of the asphalt mixtures prepared in Examples 1-3 and Comparative Examples 1-4

[0046]

[0047] It can be seen from the results in Table 1 that the water stability of the tailing asphalt mixture is still insufficient when the asphalt anti-stripping agent in Comparative Example 1 and Comparative Example 2 is used alone. The dynamic stability of rutting of Comparative Example 3 is greatly different from that of the examples, the high-temperature stability is poor, and the low-temperature bending strain also does not meet the index requirements. The indexes of each component added alone in the asphalt mixture in Comparative Example 4 are also not as good as those in the combined addition mode in the examples, so it can be seen that the tailing asphalt mixture prepared by using the tailing aggregate asphalt anti-stripping agent prepared by the application has good water stability and high and low temperature performance, and each road performance meets the use index requirements of the road pavement in the Technical Specification for Construction of Highway Asphalt Pavement (JTG F40-2004).

Claims

1. An asphalt anti-stripping agent for tailings aggregate, characterized by By mass percent, comprising the following components: Tailings powder 55%~65% Lime powder 30%~40% Fatty alcohol polyoxyethylene ether phosphate 3%~4% Silane coupling agent 1%~2%; The preparation method of the asphalt anti-stripping agent for the tailings aggregate comprises the following steps: (1) uniformly mixing fatty alcohol polyoxyethylene ether phosphate and a silane coupling agent to obtain a pre-prepared mixed solution; (2) drying and grinding iron tailings slag to a passing rate of <0.075 mm of 85~100%, and uniformly mixing the lime powder to obtain a pre-prepared mixed powder; and (3) uniformly spraying the pre-prepared mixed solution in (1) on the mixed powder in step (2) and drying to obtain the asphalt anti-stripping agent.

2. The asphalt anti-stripping agent of claim 1, wherein: The tailings powder is a magnetic separation tailings powder in a mining area, and the chemical composition comprises: 55%~60% SiO2, 10%~18% Fe2O3, 10%~15% Al2O3, and 6%~10% CaO.

3. The asphalt anti-stripping agent of claim 1, wherein: The particle size requirement of the tailings powder is that the passing rate of <0.075 mm standard square opening sieve is 85~100%.

4. The asphalt anti-stripping agent of claim 1, wherein: The lime powder is an industrial-grade lime powder, and Ca(OH)2>90wt%, 80-500 mesh.

5. The asphalt anti-stripping agent of claim 1, wherein: The fatty alcohol polyoxyethylene ether phosphate AEO-P, general formula RO(CH2CH2O) n PO3H2, wherein the fatty alcohol ROH comprises one or more of C8-18 alcohols, wherein the number of adducts of ethylene oxide (CH2CH2O) n n is 3-9.

6. The asphalt anti-stripping agent of claim 1, wherein: The silane coupling agent is one or more of vinyl triethoxysilane, γ-aminopropyl trimethoxysilane, 3-glycidyl ether propyl trimethyl silane, and γ-methacryloyl oxy propyl trimethoxysilane.

7. A method for preparing the anti-stripping agent for bitumen of tailings aggregate according to any one of claims 1 to 6, characterized by The preparation method of the asphalt anti-stripping agent for the tailings aggregate comprises the following steps: (1) uniformly mixing fatty alcohol polyoxyethylene ether phosphate and a silane coupling agent to obtain a pre-prepared mixed solution; (2) drying and grinding iron tailings slag to a passing rate of <0.075 mm of 85~100%, and uniformly mixing the lime powder to obtain a pre-prepared mixed powder; and (3) uniformly spraying the pre-prepared mixed solution in (1) on the mixed powder in step (2) and drying to obtain the asphalt anti-stripping agent.

8. The method of claim 7, wherein: In step (1), the preparation method of the fatty alcohol polyoxyethylene ether phosphate is that, under nitrogen protection, two portions of fatty alcohol polyoxyethylene ether AEO are first added, one portion of P2O5 is added in batches under stirring, and the fatty alcohol polyoxyethylene ether phosphate is obtained after hydrolysis under continuous stirring, wherein the P2O5 addition time in batches is 1.5~2h, the heating temperature is 80~90℃, and the stirring time is 4h.

9. The method of claim 7, wherein: The drying temperature in step (3) is 100~105℃, and the drying time is 2~3 hours.

10. A method of using the anti-stripping agent of any one of claims 1 to 6, characterized by Comprising: The asphalt anti-stripping agent is incorporated into the mineral powder of the tailings aggregate asphalt mixture, wherein the replacement mineral powder incorporation amount is ≥80wt%, the coarse aggregate and the fine aggregate in the tailings aggregate asphalt mixture are both iron mine waste rocks, and the mineral powder is a magnetic separation tailings powder.

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