Alkali-activated red mud-based slag mortar backfill material and preparation method thereof

Abstract

The invention relates to the technical field of mortar backfill materials, and provides an alkali-activated red mud-based slag mortar backfill material and a preparation method thereof. Comprising the following components in parts by weight: 14-18 parts of activated red mud, 4.2-5.4 parts of water glass, 35-45 parts of superfine slag powder, 1-4.5 parts of a calcium oxide expanding agent, 3-6 parts of aluminum sulfate, 40-43 parts of tailing sand, 7-8 parts of sintered desulfurization ash, 0.1-0.15 part of a water reducing agent, 0.15-0.25 part of sodium dodecyl benzene sulfonate and 2-2.5 parts of latex powder. The preparation method of the activated red mud comprises the following steps: mixing red mud with an exciting agent and a grinding aid, and carrying out ball milling treatment and aging treatment to obtain the activated red mud. By means of the technical scheme, the problem that in the prior art, the alkali-activated red-mud-based slag mortar backfill material is low in compressive strength is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mortar backfill material, in particular to an alkali-activated red mud-based slag mortar backfill material and a preparation method thereof. BACKGROUND

[0002] Red mud, as a high-alkaline waste residue, can replace traditional alkali activators (such as NaOH) to cooperatively prepare cementitious materials with slag, fly ash and other industrial solid wastes, which not only solves the problem of red mud storage pollution, but also reduces the amount of chemical activators. This system utilizes the natural alkalinity of red mud to activate the activity of waste residue, significantly improves the defects of ordinary slag mortar such as low early strength and large shrinkage, and realizes the resource utilization and value-added of solid waste.

[0003] However, the red mud produced by the Bayer process has low activity and poor activation effect when mixed with mortar for backfilling, which may result in a decrease in compressive strength and increase the risk of structural damage to the backfill material. Therefore, there is an urgent need for an alkali-activated red mud-based slag mortar backfill material with high compressive strength. SUMMARY

[0004] The present application provides an alkali-activated red mud-based slag mortar backfill material and a preparation method thereof, which solves the problem of low compressive strength of alkali-activated red mud-based slag mortar backfill material in related technologies.

[0005] The technical scheme of the present application is as follows: The present application provides an alkali-activated red mud-based slag mortar backfill material, which comprises the following components by weight: 14-18 parts of activated red mud, 4.2-5.4 parts of water glass, 35-45 parts of slag micro-powder, 1-4.5 parts of calcium oxide expanding agent, 3-6 parts of aluminum sulfate, 40-43 parts of tailings sand, 7-8 parts of sintered desulfurization ash, 0.1-0.15 parts of water reducing agent, 0.15-0.25 parts of sodium dodecyl benzene sulfonate, and 2-2.5 parts of latex powder; the preparation method of the activated red mud comprises the following steps: mixing red mud with activator and grinding aid, ball milling, and aging treatment to obtain activated red mud.

[0006] As a further technical solution, the activator is a hydroxide and a carbonate; The grinding aid is triethanolamine; The ball milling time is 30-120 min, and the aging time is 12-24 h.

[0007] As a further technical solution, the modulus of the water glass is 1.4-1.6.

[0008] As a further technical solution, the specific surface area of the slag micro-powder is 300-550 m 2 / kg.

[0009] As a further technical solution, the calcium oxide expanding agent is also modified by a modifier; The modifier is methyl stearate and silane coupling agent KH-550.

[0010] As a further technical solution, the modification process includes the following steps: first, the prepared modifier solution is sprayed onto the calcium oxide powder, and the modifier is uniformly coated by stirring at 40-80 DEG C for 10-15 min, then the reaction is ensured by continuing to stir at 40-80 DEG C for 20-40 min, finally the modified product is dried at 100-140 DEG C for 1-3 h for curing, to obtain the surface-modified calcium oxide expanding agent.

[0011] In the application, the calcium oxide expanding agent is modified by methyl stearate and silane coupling agent KH-550, which further improves the compressive strength of the alkali-activated red mud-based slag mortar backfill material.

[0012] As a further technical solution, in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:3-7; The amount of the modifier added is 1%-4%.

[0013] As a further technical solution, the water reducing agent is a polycarboxylic acid type water reducing agent.

[0014] The application also proposes a preparation method of the alkali-activated red mud-based slag mortar backfill material, for preparing the alkali-activated red mud-based slag mortar backfill material, including the following steps: S1, mixing activated red mud, slag powder, aluminum sulfate, tailings sand, sintered desulfurization ash, water reducing agent, sodium dodecyl benzene sulfonate and latex powder for 20-26 h; S2, weighing water glass solution and calcium oxide expanding agent, adding the mixed powder, and fully stirring and mixing to obtain the alkali-activated red mud-based slag mortar backfill material.

[0015] The working principle and beneficial effects of the application are: In the application, the red mud is activated by mixing with a chemical activator and a grinding aid, and the activated red mud and water glass are compounded, which effectively reduces the use of alkali activator, and proposes a new treatment method for the stacked red mud, which can utilize the high alkalinity of the red mud itself and the activation of the silicon-aluminum phase in the activated red mud, to partially replace the alkali activation effect of water glass, and synergistically act with the water glass to supplement the activity [SiO4] 4- , and improve the compressive strength of the alkali-activated red mud-based slag mortar backfill material. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work, are within the protection scope of the present application.

[0017] In the following examples and comparative examples, the specific surface area of the slag powder is 300-550m 2 / kg; the polycarboxylic acid water reducing agent is purchased from Jinan Quanchi New Material Co., Ltd.; and the red mud is a Bayer red mud.

[0018] Example 1 The alkali-activated red mud-based slag mortar backfill material comprises the following components in parts by weight: activated red mud 14 parts, water glass (modulus 1.4) 4.2 parts, slag powder 35 parts, calcium oxide expanding agent 1 part, aluminum sulfate 3 parts, tailings sand 40 parts, sintered desulfurization ash 7 parts, polycarboxylic acid water reducing agent 0.1 part, sodium dodecyl benzene sulfonate 0.15 part, and latex powder 2 parts; The preparation method of the activated red mud comprises the following steps: mixing the red mud with barium carbonate and triethanolamine, performing ball milling treatment for 80 min, and performing aging treatment for 18 h to obtain the activated red mud; The preparation method of the alkali-activated red mud-based slag mortar backfill material comprises the following steps: S1, mixing the activated red mud, the slag powder, the aluminum sulfate, the tailings sand, the sintered desulfurization ash, the polycarboxylic acid water reducing agent, the sodium dodecyl benzene sulfonate, and the latex powder for 20 h; S2, weighing the water glass solution and the calcium oxide expanding agent, adding the above mixed powder, and fully stirring and mixing to obtain the alkali-activated red mud-based slag mortar backfill material.

[0019] Example 2 The alkali-activated red mud-based slag mortar backfill material comprises the following components in parts by weight: activated red mud 18 parts, water glass (modulus 1.5) 5.4 parts, slag powder 45 parts, calcium oxide expanding agent 4.5 parts, aluminum sulfate 6 parts, tailings sand 43 parts, sintered desulfurization ash 8 parts, polycarboxylic acid water reducing agent 0.15 part, sodium dodecyl benzene sulfonate 0.25 part, and latex powder 2.5 parts; The preparation method of the activated red mud comprises the following steps: mixing the red mud with barium carbonate and triethanolamine, performing ball milling treatment for 30 min, and performing aging treatment for 24 h to obtain the activated red mud; The preparation method of the alkali-activated red mud-based slag mortar backfill material comprises the following steps: S1, mix the activated red mud, slag powder, aluminum sulfate, tailings sand, sintered desulfurization ash, polycarboxylate superplasticizer, sodium dodecyl benzene sulfonate and latex powder for 26h; S2, weigh the water glass solution and calcium oxide expanding agent, add the mixed powder, fully stir and mix uniformly to obtain the alkali-activated red mud-based slag mortar backfill material.

[0020] Example 3 The alkali-activated red mud-based slag mortar backfill material comprises the following components by weight: activated red mud 15 parts, water glass (modulus 1.6) 5 parts, slag powder 39 parts, calcium oxide expanding agent 3 parts, aluminum sulfate 4 parts, tailings sand 42 parts, sintered desulfurization ash 7.5 parts, polycarboxylate superplasticizer 0.12 parts, sodium dodecyl benzene sulfonate 0.2 parts, and latex powder 2.2 parts; The preparation method of the activated red mud comprises the following steps: mixing the red mud with barium carbonate and triethanolamine, ball milling for 120min, and aging for 12h to obtain the activated red mud; The preparation method of the alkali-activated red mud-based slag mortar backfill material comprises the following steps: S1, mix the activated red mud, slag powder, aluminum sulfate, tailings sand, sintered desulfurization ash, polycarboxylate superplasticizer, sodium dodecyl benzene sulfonate and latex powder for 26h; S2, weigh the water glass solution and calcium oxide expanding agent, add the mixed powder, fully stir and mix uniformly to obtain the alkali-activated red mud-based slag mortar backfill material.

[0021] Example 4 The difference between this embodiment and example 3 is that the calcium oxide expanding agent is further modified by a modifier. The modification process comprises the following steps: first, spray the prepared modifier solution onto the calcium oxide powder, stir at 40℃ for 15min to make the modifier uniformly coated, then continue to stir at 40℃ for 40min to ensure sufficient reaction, finally dry the modified product at 100℃ for 3h for solidification to obtain the surface-modified calcium oxide expanding agent; in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:3; in the modifier solution, the mass of the modifier is 4% of the mass of the calcium oxide powder.

[0022] Example 5 The difference between the present example and example 3 is only that the calcium oxide expander is further modified by a modifier, and the modification process comprises the following steps: first, a previously prepared modifier solution is sprayed onto the calcium oxide powder, and the modifier is uniformly coated by stirring at 80℃ for 10min, then the modified product is dried at 140℃ for 1h for solidification to obtain the surface-modified calcium oxide expander; in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:7; in the modifier solution, the mass of the modifier is 1% of the mass of the calcium oxide powder.

[0023] Comparative Example 1 The difference between the present example and example 3 is only that the calcium oxide expander is further modified by a modifier, and the modification process comprises the following steps: first, a previously prepared modifier solution is sprayed onto the calcium oxide powder, and the modifier is uniformly coated by stirring at 80℃ for 10min, then the modified product is dried at 140℃ for 1h for solidification to obtain the surface-modified calcium oxide expander; in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:7; in the modifier solution, the mass of the modifier is 1% of the mass of the calcium oxide powder.

[0024] Comparative Example 2 The difference between the present example and example 3 is only that the calcium oxide expander is further modified by a modifier, and the modification process comprises the following steps: first, a previously prepared modifier solution is sprayed onto the calcium oxide powder, and the modifier is uniformly coated by stirring at 80℃ for 10min, then the modified product is dried at 140℃ for 1h for solidification to obtain the surface-modified calcium oxide expander; in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:7; in the modifier solution, the mass of the modifier is 1% of the mass of the calcium oxide powder.

[0025] Comparative Example 3 The difference between the present example and example 3 is only that the calcium oxide expander is further modified by a modifier, and the modification process comprises the following steps: first, a previously prepared modifier solution is sprayed onto the calcium oxide powder, and the modifier is uniformly coated by stirring at 80℃ for 10min, then the modified product is dried at 140℃ for 1h for solidification to obtain the surface-modified calcium oxide expander; in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:7; in the modifier solution, the mass of the modifier is 1% of the mass of the calcium oxide powder.

[0026] Comparative Example 4 The difference between the present example and example 3 is only that the calcium oxide expander is further modified by a modifier, and the modification process comprises the following steps: first, a previously prepared modifier solution is sprayed onto the calcium oxide powder, and the modifier is uniformly coated by stirring at 80℃ for 10min, then the modified product is dried at 140℃ for 1h for solidification to obtain the surface-modified calcium oxide expander; in the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:7; in the modifier solution, the mass of the modifier is 1% of the mass of the calcium oxide powder.

[0027] The alkali-activated red mud-based slag mortar backfill materials prepared in examples 1-5 and comparative examples 1-4 are tested according to the following method: Compressive strength: unconfined compressive strength is tested according to standard ASTM D4832-16e1; The test results are shown in Table 1 below.

[0028] Table 1 Performance test results

[0029] Compared with comparative examples 1-4, the alkali-activated red mud-based slag mortar backfill materials prepared in examples 1-5 have higher unconfined compressive strength, which shows that the activation of red mud and water glass in the present application improves the compressive strength of the alkali-activated red mud-based slag mortar backfill material; compared with examples 1-3, the alkali-activated red mud-based slag mortar backfill materials prepared in examples 4-5 have higher unconfined compressive strength, which shows that the modification of calcium oxide expander by coupling agent and methyl stearate further improves the compressive strength of the alkali-activated red mud-based slag mortar backfill material.

[0030] The above merely preferred embodiments of the present application are not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. An alkali-activated red mud-based slag mortar backfill material, characterized in that, Includes the following components in parts by weight: The activated red mud comprises 14-18 parts activated red mud, 4.2-5.4 parts water glass, 35-45 parts slag powder, 1-4.5 parts calcium oxide expanding agent, 3-6 parts aluminum sulfate, 40-43 parts tailings sand, 7-8 parts sintering desulfurization ash, 0.1-0.15 parts water reducing agent, 0.15-0.25 parts sodium dodecylbenzene sulfonate, and 2-2.5 parts latex powder. The preparation method of the activated red mud includes the following steps: mixing red mud with an activator and a grinding aid, ball milling, and aging to obtain activated red mud.

2. The alkali-activated red mud-based slag mortar backfill material according to claim 1, characterized in that, The activator is a hydroxide and a carbonate; The grinding aid is triethanolamine.

3. The alkali-activated red mud-based slag mortar backfill material according to claim 2, characterized in that, The ball milling time is 30-120 min; the aging time is 12-24 h.

4. The alkali-activated red mud-based slag mortar backfill material according to claim 1, characterized in that, The modulus of the water glass is 1.4 to 1.

6.

5. The alkali-activated red mud-based slag mortar backfill material according to claim 1, characterized in that, The specific surface area of ​​the slag powder is 300~550m². 2 / kg.

6. The alkali-activated red mud-based slag mortar backfill material according to claim 1, characterized in that, The calcium oxide expanding agent is also modified by a modifier. The modifier is methyl stearate and silane coupling agent KH-550.

7. The alkali-activated red mud-based slag mortar backfill material according to claim 6, characterized in that, The modification process includes the following steps: spraying a pre-prepared modifier solution onto calcium oxide powder, stirring at 40-80°C for 10-15 minutes to ensure uniform coating of the modifier, then maintaining the temperature at 40-80°C and continuing to stir for 20-40 minutes to ensure full reaction, and finally drying the modified product at 100-140°C for 1-3 hours to cure it, thereby obtaining a surface-modified calcium oxide expanding agent.

8. The alkali-activated red mud-based slag mortar backfill material according to claim 7, characterized in that, In the modifier solution, the mass ratio of silane coupling agent KH-550 to methyl stearate is 10:3~7; In the modifier solution, the mass of the modifier is 1% to 4% of the mass of the calcium oxide powder.

9. The alkali-activated red mud-based slag mortar backfill material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent.

10. A method for preparing an alkali-activated red mud-based slag mortar backfill material, used to prepare the alkali-activated red mud-based slag mortar backfill material according to any one of claims 1 to 9, characterized in that, Includes the following steps: S1. Mix activated red mud, slag powder, aluminum sulfate, tailings sand, sintering desulfurization ash, water-reducing agent, sodium dodecylbenzene sulfonate and latex powder for 20-26 hours. S2. Weigh the water glass solution and calcium oxide expanding agent, add them to the above-mentioned mixed powder, and stir thoroughly to obtain alkali-activated red mud-based slag mortar backfill material.

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