A soil-cementitious material and a method of making the same

Abstract

The application discloses a kind of soil poly cement materials and preparation method thereof.Soil poly cement material includes the following components by weight parts: metakaolin 25-50 parts, pretreatment waste catalyst 5-30 parts, activator 10-40 parts, water 2-15 parts;Wherein the treatment process of the pretreatment waste catalyst is: waste catalyst is immersed in propylene oxide aqueous solution, then sealed heat treatment is carried out, and the material obtained by heat treatment is dried and calcined again.The soil poly cement material of the application uses a certain amount of waste catalyst as raw material, has good compressive strength and flexural strength, better solidifies heavy metals in waste catalyst, solves the problem of single soil poly cement basic raw material, and promotes the popularization and application of soil poly cement.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of building materials, and particularly relates to a geopolymer cement material and a preparation method thereof. BACKGROUND

[0002] Geopolymer cement is a new type of high-performance inorganic polymer material, and is the most promising one among alkali-activated cementitious materials. Geopolymer cement has been widely used and shows great application prospects in building materials, high-strength materials, nuclear waste materials, sealing materials and high-temperature resistant materials. Most of the application fields of geopolymer cement are the same as those of cement and ceramics. However, compared with cement and ceramics, geopolymer cement has great advantages: (1) geopolymer cement materials do not need high-temperature sintering or sintering, and the geopolymerization reaction can be completed at room temperature to 150 DEG C, and almost no NO2, SO2 and CO is generated in the production process, and the emission of CO2 is very low; (2) good construction performance, the preparation process of geopolymer cement is simple, and the geopolymer cement can be rapidly hardened at room temperature; (3) good durability, the structure of the concrete prepared from geopolymer cement is compact after hardening, and the concrete has good impermeability and frost resistance; (4) small mass loss under acidic conditions, and good corrosion resistance.

[0003] At present, the basic raw materials for preparing geopolymer cement mainly include metakaolin and fly ash, and the basic raw materials are single, which is not conducive to the promotion of geopolymer cement. CN111847935A discloses a geopolymer cement material and a preparation method thereof. The geopolymer cement material comprises the following components in parts by weight: metakaolin 25-50 parts, waste catalyst 5-25 parts, activator 10-40 parts and water 2-15 parts. The geopolymer cement material of the application is doped with a certain amount of waste catalyst, and the problem of single basic raw material of geopolymer cement is solved, but the compressive strength and the flexural strength still need to be improved. SUMMARY

[0004] In view of the defects of the prior art, the present application provides a geopolymer cement material and a preparation method thereof. The geopolymer cement material of the present application uses a certain amount of waste catalyst as raw material, has good compressive strength and flexural strength, better solidifies the metal in the waste catalyst, solves the problem of single basic raw material of geopolymer cement, and can better promote the popularization and application of geopolymer cement.

[0005] The present application provides a geopolymer cement material, which comprises the following components in parts by weight: metakaolin 25-50 parts, pretreated waste catalyst 5-30 parts, activator 10-40 parts and water 2-15 parts; preferably, metakaolin 30-45 parts, pretreated waste catalyst 5-25 parts, activator 15-35 parts and water 2-10 parts; wherein the pretreatment process of the pretreated waste catalyst is as follows: the waste catalyst is immersed in an epoxy propane aqueous solution, then sealed and heat treated, and the material obtained by heat treatment is dried and calcined.

[0006] In the present application, the waste catalyst can be various waste catalysts containing heavy metals (such as at least one of rare earth metals, nickel, etc.). The waste catalyst is a refinery waste catalyst, which can be at least one of a residue hydroprocessing waste catalyst, a catalytic cracking waste catalyst, etc., and the residue hydroprocessing waste catalyst can be at least one of a hydrodesulfurization waste catalyst, a hydrodenitrogenation waste catalyst, a hydrodemetallization waste catalyst; preferably a catalytic cracking waste catalyst.

[0007] In the present application, the content of amorphous alumina in the waste catalyst is generally not less than 10wt%, further not less than 20wt%, and preferably not less than 30wt%, based on the weight of the waste catalyst.

[0008] In the present application, the mass percentage concentration of the propylene oxide aqueous solution is 2.5%-12%, preferably 4%-8%, and the mass ratio of the amount of propylene oxide aqueous solution to the waste catalyst is 3:1-10:1, preferably 4:1-8:1.

[0009] In the present application, the sealing heat treatment is preferably carried out in a sealed autoclave, and the sealing heat treatment is preferably first carried out at 60-100℃ for 1-4 hours, and then carried out at 120-160℃ for 2-6 hours.

[0010] In the present application, the drying temperature is 100-160℃, the drying time is 2-8 hours, the calcination temperature is 500-750℃, and the calcination time is 4-6 hours, and the calcination is carried out in an oxygen-containing atmosphere, preferably an air atmosphere.

[0011] In the present application, the activator is one or more of sodium hydroxide, sodium carbonate or water glass, and the activator is preferably composed of 10-20 parts by mass of NaOH and 30-50 parts by mass of water glass, wherein the modulus of the water glass is preferably 1-2.0. The activator is generally added in the form of an aqueous solution.

[0012] The preparation method of the soil polymeric cement material of the present application comprises the following steps: mixing the waste catalyst, metakaolin and water uniformly, then adding the activator and mixing uniformly to obtain the soil polymeric cement material.

[0013] The soil polymeric cement material of the present application can be formed into a soil polymeric cement product by using a conventional mold forming method, such as injecting the soil polymeric cement material into a mold to form a desired shape, curing at a temperature of 20-80℃ and a relative humidity of 90%-95% for 1-28d, and then demolding to obtain the soil polymeric cement product.

[0014] In the present application, the waste catalyst is first ground to a particle size range of 20-100 μm, preferably 30-68 μm, and then mixed with metakaolin and water.

[0015] In the present application, the metakaolin is obtained by calcining kaolin raw powder at high temperature, and the general calcining conditions are as follows: calcining at 600-800 ℃ for 2-4 h. The main chemical composition of the metakaolin includes: the content of SiO2 is 48%-58%, the content of Al2O3 is 38%-48%, preferably the content of SiO2 is 48%-52%, and the content of Al2O3 is 40%-45%.

[0016] In the present application, the waste catalyst, metakaolin and water are mixed uniformly, and then an activator is added and mixed uniformly. The mixing can be carried out by conventional methods such as stirring. The mixing can be carried out at room temperature. The addition mode of each material can be one-time addition or multiple times addition.

[0017] Compared with the prior art, the present application has the following advantages:

[0018] The present application pretreats the waste catalyst, which can change the surface of the waste catalyst into a uniform worm-like structure, and the pretreatment process can well solidify the metals such as Ni, La and Ce in the catalyst. The structure is combined more closely with other components of the geopolymer cement material compared with the long strip-shaped rod structure in the prior art, further enhances the compressive strength and flexural strength, expands the basic raw material of the geopolymer cement, turns waste into treasure, and has a broad application and promotion prospect. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 SEM image of the pretreated waste FCC catalyst obtained in Example 1. DETAILED DESCRIPTION

[0020] The technical solutions and technical effects of the present application will be further illustrated below in combination with examples, but are not limited to the following examples.

[0021] In the present application, the properties of the geopolymer cement material are measured by the following methods:

[0022] Metal content test: a Japanese science ZSX100E type X-ray fluorescence spectrometer is used to analyze the mass fraction of all components of the sample, and the working parameters are: tube current 100 mA, tube voltage 30 kV, PC detector, PET crystal, standard collimator, and field grating is 30 mm. The prepared geopolymer cement sample is ground to a particle size range of 50-100 μm with a mortar, and 2 g is taken for metal content test.

[0023] The microstructure of the catalyst surface was characterized using scanning electron microscopy. The specific operation was as follows: The microstructure of the support was characterized using a JSM-7500F scanning electron microscope with an accelerating voltage of 5KV, an accelerating current of 20µA, and a working distance of 8mm.

[0024] Flexural strength test: The test is conducted using the center loading method and a flexural testing machine. A standard specimen made of cementitious material is placed sideways into the flexural testing machine, and the loading rate is 70 N / s until fracture. Both halves of the specimen are kept moist until the compressive strength test. Flexural strength calculation formula: R f =1.5F f L / b 3 , where R f Represents flexural strength, MPa, F f The maximum load that causes the specimen to break is N, L is the center distance between the supporting cylinders (mm), and b is the side length of the square cross-section of the specimen (mm). The flexural strengths at 3d and 28d of curing were measured respectively.

[0025] Compressive strength test: The broken specimen is immediately subjected to a compressive strength test on the compressive strength testing machine. The compressive strength test is conducted on the two sides perpendicular to the surface of the specimen during molding. The specimen is placed flat on the pressure plate of the cement testing machine, with both the front and back of the specimen extending beyond the pressure plate. The test speed is 2.4 kN / s until the testing machine automatically stops. The compressive strength calculation formula is: Rc = Fc / A, where Rc represents the compressive strength (MPa), Fc is the maximum load on which the specimen breaks under pressure (N), and A is the bearing area of ​​the specimen (mm²). 2 The compressive strength was measured at 3 days and 28 days of curing, respectively.

[0026] Setting Time Test: Pour all the prepared cementitious material into the mold, and place the mold on a horizontally placed glass plate. Count the time from the moment water is first added. The test block needs to be cured for a certain period before being removed. Place the mold, along with the glass plate, under the probe of the setting time tester, ensuring it lightly contacts the surface of the cementitious material. Tighten the screw and then suddenly loosen it, allowing the probe to fall vertically and freely into the cementitious paste. Observe the probe reading within 30 seconds after loosening the screw. When the tester reading is 4 ± 1 mm, the cementitious material has initially set; record this time as the initial setting time. For the final setting time test, rotate the mold and replace it with a ring probe. When the probe fails to leave a mark on the solidified cementitious material, the paste has reached final setting; record this time as the final setting time.

[0027] The main components of the catalytic cracking waste catalyst used in the embodiment of the application are as follows, based on the weight of the catalytic cracking waste catalyst: the content of Al2O3 is 53%, the content of SiO2 is 38%, the content of Ce2O is 2.8%, the content of NiO is 1.5%, and the content of La2O3 is 1.4%. The waste catalyst used is ground to a particle size range of 30-80 μm before pretreatment. The metakaolin used is obtained by calcining kaolin raw powder at a high temperature of 700 ℃ for 3 hours, and its main components include, by mass fraction: the content of SiO2 is 50%, and the content of Al2O3 is 45%. Example 1

[0028] 25 parts of waste FCC catalyst is mixed with 100 parts of propylene oxide aqueous solution with a concentration of 5 wt%, and then transferred to an autoclave. After sealing, the autoclave is placed in an oven for sealed treatment at 80 ℃ for 2 hours, and then heated to 145 ℃ for sealed treatment for 3 hours. After treatment, the material is cooled, washed, filtered, dried at 130 ℃ for 4 hours, calcined at 550 ℃ for 4 hours, and the pretreated waste FCC catalyst is obtained. The SEM image of the pretreated waste FCC catalyst is shown in Figure 1 . As can be seen from Figure 1 , a worm-like structure is formed on the surface of the waste catalyst.

[0029] The activator is composed of 10 parts of NaOH and 30 parts of water glass by mass, and the original modulus of the water glass is 3.2, which is adjusted to 1.8.

[0030] 18 parts of pretreated waste FCC catalyst, 45 parts of metakaolin, and 4 parts of water are stirred uniformly, and then 15 parts of the above activator is added and stirred uniformly to obtain a geopolymer material. The geopolymer material is tested for setting time, wherein the mold surface is coated with oil, the mixture is added to the mold and tamped, the surface is flattened with a spatula, the setting time is measured, and the mold is placed in a constant temperature and humidity box with a humidity of 90% and a temperature of 20 degrees. After 24 hours, the mold is demolded, and the strength is measured after 3 days and 28 days of curing. The specific results are shown in Table 1. Example 2

[0031] 30 parts of waste FCC catalyst is mixed with 100 parts of propylene oxide aqueous solution with a concentration of 6 wt%, and then transferred to an autoclave. After sealing, the autoclave is placed in an oven for sealed treatment at 90 ℃ for 2 hours, and then heated to 155 ℃ for sealed treatment for 3 hours. After treatment, the material is cooled, washed, filtered, dried at 120 ℃ for 5 hours, and calcined at 550 ℃ for 4 hours to obtain a pretreated waste FCC catalyst. The SEM image of the pretreated waste FCC catalyst is shown in Figure 1 . As can be seen from Figure 1 , a worm-like structure is formed on the surface of the waste catalyst.

[0032] The activator is composed of 15 parts by mass of NaOH and 40 parts by mass of water glass, the original modulus of which is 3.2, and the modulus is adjusted to 1.6.

[0033] Take 12 parts of pretreated waste FCC catalyst, 40 parts of metakaolin, and 2 parts of water, stir uniformly, then add 28 parts of the above-mentioned activator, stir uniformly, to obtain a geopolymer cement material. The setting time and strength are measured by the method of Example 1. The specific results are shown in Table 1. Example 3

[0034] Mix 25 parts of waste FCC catalyst with 100 parts of propylene oxide aqueous solution with a concentration of 8wt%, transfer to an autoclave, seal and place in an oven at 80℃ for 2 hours, then heat to 145℃ for 3 hours, after treatment, the material is cooled, washed, filtered, dried at 130℃ for 4 hours, and calcined at 550℃ for 4 hours to obtain pretreated waste FCC catalyst; the SEM image of the pretreated waste FCC catalyst is shown in Figure 1 . As can be seen from Figure 1 , a worm-like structure is formed on the surface of the waste catalyst.

[0035] The activator is the same as in Example 1.

[0036] Take 9 parts of pretreated waste FCC catalyst, 45 parts of metakaolin, and 8 parts of water, stir uniformly, then add 30 parts of the activator, stir uniformly, to obtain a geopolymer cement material. The setting time and strength are measured by the method of Example 1. The specific results are shown in Table 1.

[0037] Comparative Example 1

[0038] According to CN111847935A Example 1, a geopolymer cement product is prepared, and the specific results are shown in Table 1.

[0039] Comparative Example 2

[0040] The same as Example 1, except that the concentration of the propylene oxide aqueous solution is 1wt%, and no worm-like structure is formed on the surface of the waste catalyst.

[0041] Table 1

[0042]

[0043] The metal content test results of the soil poly cement materials obtained in Examples 1-3 before and after the heavy metal loss rate test are shown in Table 2. The heavy metal loss rate test method is as follows: 5 g of the material to be tested is placed in a 500 mL beaker, 250 mL of deionized water is added, and the stirring is started on a magnetic stirrer (800 rpm / min) to keep the pH at 7±0.5. The stirring and leaching are performed for 2 h, and after 5 min of standing, the residue is filtered, transferred to another beaker, 250 mL of deionized water is added, and the stirring is started on a magnetic stirrer (800 rpm / min) to adjust the pH to 3.2±0.5. The leaching is performed for 7 h, and then the residue is collected by filtration after standing, dried, and subjected to metal content test.

[0044] Table 2 Metal content of the soil poly cement materials before and after the heavy metal loss rate test

[0045] Example 1 (before) Example 1 (after) Example 2 (before) Example 2 (after) Example 3 (before) Example 3 (after) Ce 2 O, wt% 0.65 0.65 0.41 0.41 0.30 0.30 La2O3, wt% 0.34 0.34 0.22 0.22 0.16 0.15 NiO, wt% 0.35 0.35 0.20 0.19 0.15 0.14

Claims

1. A geopolymer cementitious material characterised in that The product comprises, by weight, the following components: 25-50 parts metakaolin, 5-30 parts pretreated waste catalyst, 10-40 parts activator, and 2-15 parts water; wherein the pretreated waste catalyst is treated by immersing the waste catalyst in an aqueous propylene oxide solution, followed by sealed heat treatment, and the resulting material is then dried and calcined; the aqueous propylene oxide solution has a mass percentage concentration of 2.5%-12%, and the mass ratio of the aqueous propylene oxide solution to the waste catalyst is 3:1-10:1; the sealed heat treatment is carried out in a closed high-pressure autoclave, first at 60-100℃ for 1-4 hours, and then at 120-160℃ for 2-6 hours; The spent catalyst is any spent catalyst containing heavy metals; based on the weight of the spent catalyst, the content of amorphous alumina is not less than 10 wt%.

2. A geopolymer cementitious material according to claim 1 characterised in that: The clay-cement material comprises, by weight, the following components: 30-45 parts metakaolin, 5-25 parts pretreated waste catalyst, 15-35 parts activator, and 2-10 parts water.

3. The geopolymer cementitious material of claim 1, wherein: The waste catalyst mentioned is a waste catalyst from catalytic cracking.

4. The geopolymer cementitious material of claim 1, wherein: Based on the weight of the spent catalyst, the content of amorphous alumina shall not be less than 20 wt%.

5. The earth-based cementitious material according to claim 4, characterized in that: Based on the weight of the spent catalyst, the content of amorphous alumina shall not be less than 30 wt%.

6. The earth-based cementitious material according to claim 1, characterized in that: The propylene oxide aqueous solution has a mass percentage concentration of 4%-8%, and the mass ratio of the propylene oxide aqueous solution to the waste catalyst is 4:1-8:

1.

7. The cementitious material according to claim 1, characterized in that: The drying temperature is 100-160℃, the drying time is 2-8 hours, the calcination temperature is 500-750℃, the calcination time is 4-6 hours, and the calcination is carried out in an oxygen-containing atmosphere.

8. The cementitious material according to claim 7, characterized in that: The roasting is carried out in an air atmosphere.

9. The cementitious material according to claim 1, characterized in that: The activator is one or more of sodium hydroxide, sodium carbonate, or water glass.

10. The earth-based cementitious material according to claim 9, characterized in that: The activator is composed of 10-20 parts by mass of NaOH and 30-50 parts by mass of water glass, wherein the modulus of the water glass is 1-2.

0.

11. The earth-based cementitious material according to claim 1, characterized in that: The metakaolin is obtained by high-temperature calcination of raw kaolin powder. The calcination conditions are as follows: calcination at 600-800℃ for 2-4 hours. The main chemical composition of the metakaolin, by mass fraction, includes: SiO2 content of 48%-58% and Al2O3 content of 38%-48%.

12. The earth-based cementitious material according to claim 11, characterized in that: The main chemical composition of the metakaolin, by mass fraction, includes: 48%-52% SiO2 and 40%-45% Al2O3.

13. The method for preparing the earth-polymer cementitious material according to any one of claims 1 to 12, characterized in that... The process includes the following steps: mixing pretreated waste catalyst, metakaolin, and water evenly, then adding an activator and mixing evenly to obtain the aforementioned clay-cement material.

14. The preparation method according to claim 13, characterized in that: The pretreated waste catalyst is first ground to a particle size range of 20~100μm, and then mixed with metakaolin and water.

15. The preparation method according to claim 13, characterized in that: The pretreated waste catalyst is first ground to a particle size of 30-68μm, and then mixed with metakaolin and water.

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