CN104163615A - Slag based mesoporous material and preparation method thereof - Google Patents

Abstract

The invention discloses a slag based mesoporous material and a preparation method thereof; the slag based mesoporous material is prepared by putting raw material slag, sodium hydroxide water and pore increasing agent glucose into a mixing device for mixing, using a die for molding, curing, and burning; and taking the adding quantity of the slag mass as a basis, the adding quantity of the sodium hydroxide is 6% of the slag mass, the adding quantity of the pore increasing agent glucose is 3%-6% of the slag mass, and the ratio of water adding quantity to slag mass is 0.24-0.28. Compared with a sample free of the pore increasing agent, after addition of the pore increasing agent in an optimum adding amount, the mesopore volume of a sample is increased by 102.63%; slag can be completely used in one time, the slag based mesoporous material with high added value can be obtained, the whole process is simple, no slag treatment is needed, no three wastes is discharged, the slag based mesoporous material is green and environmentally-friendly, and controllable preparation of the slag based mesoporous material can be realized.

Description

A kind of slag-based mesoporous material and preparation method thereof

technical field

The invention belongs to the field of resource recycling of solid waste and preparation of new materials, and in particular relates to a slag-based mesoporous material and a preparation method thereof.

Background technique

Blast furnace slag is a kind of waste slag discharged from the blast furnace when pig iron is smelted. Usually, about 0.3-0.9 tons of blast furnace slag is discharged for every ton of pig iron produced. In 2012, the output of pig iron in China reached 658 million tons, and the slag discharged was 1.97-5.9 As many as one hundred million tons. At present, slag is mainly used to produce slag cement or as an admixture of cement and concrete to produce slag powder, to produce inorganic coatings, as a sewage treatment agent, to manufacture calcium-silicon fertilizer, and as a glass raw material ^[1] . In recent years, blast furnace slag has also been used to prepare alkali-activated slag-based geopolymers ^[2-4] . In addition, Chinese patent applications by Zhang Yaojun ^[5,6] et al. (Patent No.: ZL201210166585.5, ZL201210166597.8) disclose chemically excited slag-based composite gelling materials for dye degradation and new energy research. In recent years, some patent documents have disclosed the use of solid waste to prepare mechanically macroporous materials; for example, the Chinese patent (CN101708399A) of Yu Yanzhen ^[7] discloses a porous slag filter material and its preparation method, according to the slag 30-80 %, clay 15-50%, pore-forming agent 5-20% (coal gangue, starch, sawdust, calcium carbonate, one of them) by weight percentage of raw materials, stir evenly, sprinkle water and form raw material balls, dry, 400 Preheating at -700oC and then roasting at 1000-1300oC to obtain a porous slag filter material. The patent reports that the water slag filter material prepared by this method is porous and has a large pore size. The Chinese patent (CN102603355A) of Chao Qi ^[8] etc. discloses a kind of base geopolymer porous material, and this invention patent is made of slurry (20-50 parts of water glass, 20-50 parts of slag, 10-20 parts of fly ash) parts, 10-20 parts of metakaolin, 0.1-1.5 parts of polypropylene fiber, and 0.3-1.0 parts of redispersible latex powder composed of polyvinyl alcohol powder, vinyl acetate and ethylene copolymer powder) and composite foaming agent ( The composite foaming agent is composed of the following raw materials in parts by weight: 24-35 parts of hydrogen peroxide, 64-75 parts of water, 0.5-1 part of foam stabilizer, and 1-1.5 parts of animal foaming aid) according to the weight ratio of 9-38: 1; the strength of the foam block prepared by this application is between 0.5-8MPa, the method is complicated to obtain materials, and the prepared material has the characteristics of macroscopic macropores. The Chinese patent application (CN 102584318 A) by Tian Jianjun ^[9] discloses a method for preparing porous insulation materials containing Cr-containing slag. The invention uses Cr-containing slag and fly ash as raw materials, and waste glass, clay and bentonite as bonding materials. Limestone, SiC, carbon powder, paraffin, stearic acid, organic fiber and millet are pore-enlarging agents, and the mass ratio of 40%-70% Cr-containing slag, 10%-40% binder and 5%-30% The pore-forming agent is crushed, mixed, formed, demolded and sintered at 700-1300°C. It can be seen from the scanning electron microscope pictures given in the patent application documents that the thermal insulation material with mechanical macropores is obtained by using this method.

Mesoporous materials are a class of materials with pore diameters between micropores and macropores. According to the definition of the International Union of Pure and Applied Chemistry (IUPAC) ^[10] , porous materials can be divided into microporous materials ( Pore diameter less than 2nm), mesoporous material (pore diameter between 2-50nm) and macroporous material (pore diameter greater than 50nm). Due to the different arrangement and distribution of pores in space, mesoporous materials can be divided into two types: ordered and disordered ^[11] . The use of cationic surfactants as structural templates is a classic method for the synthesis of M41S series ordered mesoporous materials ^{[12, 13]} and the sol-gel method is a typical method for preparing disordered oxide mesoporous materials. Disordered mesoporous materials have the characteristics of complex, irregular and disconnected pore shapes and wide pore size distribution.

To sum up, the applicant did not find any literature and patent reports on the preparation of mesoporous materials using solid waste slag through a large number of literature searches and domestic and foreign patent novelty searches.

The following are the main references given by the inventors:

[1] Cao Deqiu, Li Canhua, Progress in utilization of blast furnace slag resources in my country, China Scrap Iron and Steel 5 (2006) 26-29.

[2] J Davidovits. Geopolymers: inorganic polymeric new materials, Journal of Thermal Analysis 37(1991) 1633-1656.

[3] Zhang Shuzheng, Gong Kecheng, Geopolymers, Journal of Materials Science and Engineering 21 (3) (2003) 430-436.

[4] Wang Feng, Zhang Yaojun, NaOH Alkali Excited Slag Geopolymer, Nonmetallic Minerals 31 (3) (2008) 9-11.

[5] Zhang Yaojun, Liu Licai, Ni Lulu, Wang Bingli, Wang Yachao, Chai Qian, Jing Dongsheng, Gu Xiaoze, Liu Peiyao, Slag-based cementitious material-iron oxide semiconductor composite catalyst and its application in solar photocatalytic water splitting for hydrogen production , Patent No.: ZL201210166585.5.

[6] Zhang Yaojun, Liu Licai, Ni Lulu, Wang Bingli, Wang Yachao, Slag-based inorganic polymer-iron oxide semiconductor composite catalyst and its application in dye degradation, patent number: ZL201210166597.8.

[7] Yu Yanzhen, Feng Yan, Wang Jiabin, Tan Juan, Zhao Chunhui, Sun Yong, Liu Zhenliang, Zhao Youheng, A porous water slag filter material and its preparation method, publication number: CN101708399A.

[8] Chao Qi, Liu Haifeng, A basic geopolymer porous material, publication number: CN02603355A.

[9] Tian Jianjun, Zhang Shengen, Zhang Jing, Pan Dean, Liu Bo, A method for preparing porous insulation materials from Cr-containing slag, publication number: CN102584318A.

[10] D.H.Everett, IUPAC manual of symbols and terminology, Pure and Applied Chemistry 31(1972) 578-638.

[11] P.Schmidt-Winkel, W.W.Lukens, D.Jr Zhao, et a1., Mesocellular siliceous foams with uniform sized cells and windows, Journal of the American Chemical Society 121(1999) 254-255.

[12] J.S.Beck, J.E.Vartwli, et a1., A new family of mesoporousmolecular sieves prepared with liquid-crystal template mechanism, Journal of the American Chemical Society 114(1992) 10834-10843.

[13] G.T.Kresge, M.E.Leonowica, et a1., Ordered mesoporousmolecular sieves synthesized by liquid-crystal template mechanism, Nature 359(1992) 710-712.

Contents of the invention

The object of the present invention is to provide a slag-based mesoporous material and a preparation method thereof.

In order to realize above-mentioned task, the present invention takes following technical solution:

A slag-based mesoporous material is characterized in that the slag-based mesoporous material is prepared by putting raw material slag, sodium hydroxide water and pore-enhancing agent glucose into a stirring device for mixing, and then molded, maintained and It is roasted, the amount of sodium hydroxide and pore-enhancing agent glucose is based on the mass of slag; the amount of sodium hydroxide added is 6% of the mass of slag; the amount of pore-enhancing agent glucose is 3%-6% of the mass of slag , the ratio of the amount of water added to the mass of slag is 0.24-0.28.

The above-mentioned slag-based mesoporous material and its preparation method are characterized in that they include the following steps:

(1) take slag powder and water by formula quantity; The mass ratio of water and slag powder is: 0.24-0.28;

(2) take sodium hydroxide by formula quantity, and it is dissolved in appropriate amount of water to form sodium hydroxide aqueous solution;

(3) Take the pore-enhancing agent glucose according to the formula, and dissolve it into an appropriate amount of water to form an aqueous glucose solution;

(4) At room temperature, pour the sodium hydroxide aqueous solution into the stirring container, then add the pore-enhancing agent glucose aqueous solution, and then add the slag powder for mixing to form a slurry;

(5) Put the slurry into a mold to form it, and cure it in a constant temperature box at 80°C for 6 hours, remove the mold after natural cooling, and cure it in a curing room for 1 day to obtain a slag-based cementitious material test block.

(6) Put the test block of slag-based cementitious material into a horse boiling furnace and raise the temperature to 450°C at a heating rate of 5°C/min, keep it for 4 hours, let it cool naturally and take it out to obtain a slag-based mesoporous material.

The technical effect brought by the slag-based mesoporous material prepared by the present invention is:

(1) It can promote the development of circular economy in ironworks, and provides a new way for the one-time, completely harmless, high value-added, large-scale and resource utilization of slag.

(2) The raw materials are cheap and easy to obtain, the process is simple, no pretreatment of slag is required, no three wastes are discharged, and it is green and environmentally friendly; the controllable preparation of mesoporous materials can be realized.

(3) The prepared slag-based mesoporous material has high compressive strength, which can meet the needs of catalysts and adsorbents for mesoporous materials.

The innovation of the present invention lies in:

A new method of preparing slag-based mesoporous materials using glucose as a pore-enhancing agent was proposed; at the same time, by controlling the dose of pore-increasing diameter and roasting temperature, the controllable preparation of slag-based mesoporous materials was realized, and the types of mesoporous materials were enriched. Compared with the sample without porogen, the mesopore volume of the sample can be increased by 102.63% after adding the optimal amount of porogen.

Description of drawings

Fig. 1 is the technological process of preparation of slag-based mesoporous material;

Fig. 2 is the pore size distribution curve of the slag-based mesoporous material detected by the BET method;

Fig. 3 is the thermal analysis curve of glucose;

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments.

Detailed ways

The inventor's technical idea is to use solid waste slag as raw material and glucose as a pore-enhancing agent to realize the slag-based mesoporous material by adjusting the preparation conditions, especially the dosage of the pore-enhancing agent and the roasting temperature. The controllable preparation of mesoporous materials enriches the types of mesoporous materials. At the same time, the preparation process requires simple technology, does not require pretreatment of the slag, and can completely utilize the slag at one time, which is of great significance for the high value-added utilization of the slag and the circular economy of iron and steel enterprises.

Fig. 1 has provided the technological flow block diagram of preparation of slag-based mesoporous material; In the following examples, the main raw material that prepares slag-based mesoporous material is industrial solid waste slag, sodium hydroxide; Glucose, specific performance is as follows :

1. Slag:

The slag comes from Hancheng Longgang Company. The slag was dried in an oven at 110°C for 3 hours and ball milled for 2 hours. The density was 2.82g/cm ³ and the Blaine specific surface area was 520m ² /kg.

Main oxide composition of slag (mass percentage): SiO ₂ (30.01%), Al ₂ O ₃ (11.98%), CaO (37.39%), MgO (8.20%), Fe ₂ O ₃ (0.25%), TiO ₂ (1.17%), _SO3 (1.30%), _Na2O (0.64%), _K2O (0.83%) others (8.23%).

2. Sodium hydroxide

Sodium hydroxide was purchased from Jindong Tianzheng Fine Chemical Reagent Factory, Tianjin, and was an analytically pure reagent.

3. Glucose

Glucose was purchased from Jindong Tianzheng Fine Chemical Reagent Factory, Tianjin, and was an analytically pure reagent.

4. The pore size distribution of slag-based mesoporous materials was detected by BET method.

The following are examples given by the inventors. It should be noted that these examples are only for better understanding of the present invention, and the present invention is not limited to these examples.

Example 1:

Accurately weigh 600g of slag powder as the measurement basis (100%); adopt the external mixing method, the sodium hydroxide dosage is 6% of the slag powder quality, and the ratio of water to slag powder quality is 0.28.

Sodium hydroxide was dissolved in water at room temperature to form an aqueous sodium hydroxide solution. Pour the aqueous solution into a double-rotation double-speed slurry mixer, then add slag powder for mixing to form a uniform slurry, put the slurry into a 31.5mm×31.5mm×50mm steel triple mold for molding, and put the triple mold Put it into a plastic film sealed bag, and cure it at 80°C in a constant temperature box for 6 hours. After cooling, remove the mold, and cure it at room temperature for 1 day to obtain a slag-based cementitious material test piece, and its compressive strength is 41MPa.

Put the slag-based gel material test block into a horse-boiling furnace, raise the temperature to 450°C at a heating rate of 5°C/min, keep it warm for 4 hours, let it cool naturally, and then take it out to obtain a slag-based gel material. The compressive strength is tested as 65.8MPa; the pore size distribution of the sample was detected by BET method, and the results are shown in Table 1 and Figure 2. It can be seen from Table 1 that the mesopore volume of the slag-based cementitious material is 0.048956 (mL/g).

Table 1: Pore size distribution results of samples detected by BET method

Example 2:

Accurately weigh 600g of slag powder, take this as the basis of measurement (100%); adopt external mixing method, sodium hydroxide dosage is 6% of slag powder quality, pore-enhancing agent glucose dosage is 3% of slag quality, water and The mass ratio of slag powder is 0.24. Sodium hydroxide is dissolved in water at room temperature to form an aqueous sodium hydroxide solution; solid glucose is dissolved in water to form an aqueous glucose solution. Pour the sodium hydroxide aqueous solution and the glucose aqueous solution into the double-rotation double-speed slurry mixer in turn, then add slag powder for mixing to form a uniformly mixed slurry, and put the slurry into a 31.5mm×31.5mm×50mm steel triplex Molded in the mold, put the triple mold into a plastic film sealed bag, cured for 6 hours in a constant temperature box at 80°C, cooled and removed the mold, and cured at room temperature for 1 day to obtain a slag-based cementitious material test piece, and its compressive strength was tested to be 60.7 MPa.

Put the obtained slag-based cementitious material test block into a horse boiling furnace, raise the temperature to 450°C at a heating rate of 5°C/min, keep it for 4 hours, let it cool naturally, and take it out to obtain a slag-based mesoporous material. Test its resistance The compressive strength was 80.3 MPa; the pore size distribution of the sample was detected by BET method, and the results are shown in Table 1 and Figure 2. It can be seen from Table 1 that the mesoporous volume of the slag-based mesoporous material is 0.080229 (mL/g). Compared with the mesopore volume of the slag-based cementitious material without the pore-enhancing agent, the volume of the mesopores increased by 0.031273 (mL/g), and the percentage of the increased mesopore volume was 63.87%; area increased significantly.

The reason why the calcination temperature for preparing slag-based mesoporous materials is selected as 450°C is based on the weight loss (%) in the thermal analysis curve of glucose in Figure 3 and the maximum temperature of 312°C for weight loss in the differential thermogravimetric curve. Ensure the complete decomposition of glucose, so 450°C is selected as the complete decomposition temperature of glucose.

Example 3:

Accurately weigh 600g of slag powder, take this as the basis of measurement (100%); adopt external mixing method, sodium hydroxide dosage is 6% of slag powder quality, pore-enhancing agent glucose dosage is 6% of slag quality, water and The mass ratio of slag powder is 0.24. Dissolve solid sodium hydroxide in water at room temperature to form an aqueous sodium hydroxide solution. Dissolve solid glucose in water to form an aqueous glucose solution. Add sodium hydroxide aqueous solution and glucose aqueous solution to the double-rotation double-speed slurry mixer in turn, then add slag powder for mixing to form a uniformly mixed slurry, and put the slurry into a 31.5mm×31.5mm×50mm steel triple mold Put the triple mold into a plastic film sealed bag, and maintain it in a constant temperature box at 80°C for 6 hours, cool and remove the mold, and after curing at room temperature for 1 day, a slag-based gelled test block was obtained, and its compressive strength was tested to be 54.6MPa.

Put the slag-based gelled test block into a horse-boiler, raise the temperature to 450°C at a heating rate of 5°C/min, keep it for 4 hours, let it cool naturally, and take it out to obtain a slag-based mesoporous material. The compressive strength is tested as 90.4MPa; BET method detects the pore size distribution of the sample, and the results are shown in Table 1 and Figure 2. As can be seen from Table 1, the mesoporous volume of the slag-based mesoporous material is 0.099200 (mL/g), which is higher than that without The mesopore volume of the slag-based gelling material of the porogen increases by 0.050244 (mL/g), and the increased mesopore volume percentage is 102.63%; at the same time, it can be seen from Figure 2 that the curve area of the 2nm-50nm pore diameter increases significantly , its most integrable pore size shifts significantly towards the mesopore direction. It shows that the controllable preparation of slag-based mesoporous materials can be realized as long as the dose of pore enhancer glucose, roasting temperature and heating rate are controlled.

Example 4:

The slag-based mesoporous material prepared in Example 3 was used as a catalyst carrier, and 5% by mass of tungsten trioxide was loaded as a catalyst.

Accurately weigh 0.4 g of the above catalyst, put it into a beaker containing 100 mL of 4 mg/L alkaline violet aqueous solution under magnetic stirring, and irradiate the aqueous solution in the beaker vertically from the top of the beaker with a simulated visible light source (500W xenon lamp) , carry out the photocatalytic degradation of the dye, and irradiate for 70 minutes, and the degradation rate of basic violet is 97%; and under the same conditions, the degradation rate of pure tungsten trioxide to basic violet is 60%; it shows that the slag-based Mesoporous materials have high visible light catalytic activity as catalyst supports.

Claims (4)

1. a slag-based mesoporous material, it is characterized in that, this slag-based mesoporous material making is raw material slag, sodium hydroxide water and pore forming agent glucose to be put into whipping appts carry out mix, through mould molding, maintenance and roasting thereof, form, the add-on of sodium hydroxide and pore forming agent glucose be take slag quality as basis; The add-on of sodium hydroxide is 6% of slag quality; Pore forming agent glucose addition is the 3%-6% of slag quality, and the addition of water and slag mass ratio are 0.24-0.28.

2. slag-based mesoporous material as claimed in claim 1, is characterized in that, the main oxides mass percent of described slag consists of: SiO ₂: 30.01%, Al ₂o ₃: 11.98%, CaO:37.39%, MgO:8.20%, Fe ₂o ₃: 0.25%, TiO ₂: 1.17%, SO ₃: 1.30%, Na ₂o:0.64%, K ₂o:0.83%, other: 8.23%.

3. the preparation method of the slag-based mesoporous material described in claim 1 or 2, is characterized in that, comprises the following steps:

(1) by formula ratio, take slag powders and water; The mass ratio of water and slag powders is: 0.24-0.28;

(2) press formula ratio weighing sodium hydroxide, and dissolved in and in suitable quantity of water, form aqueous sodium hydroxide solution;

(3) by formula, take pore forming agent glucose, and dissolved in and in suitable quantity of water, form D/W;

(4) under room temperature, aqueous sodium hydroxide solution is poured in stirred vessel, then D/W is added, then slag powders is added and carry out mix, form slurry;

(5) pack slurry into die for molding, maintenance 6h under 80 ℃ of conditions of thermostat container, form removal after naturally cooling, curing room natural curing 1 day, obtains the test block of slag-based gelling material;

(6) test block of slag-based gelling material is put into muffle furnace and be warming up to 450 ℃ with the temperature rise rate of 5 ℃/min, after insulation 4h, make to take out after its naturally cooling, obtain slag-based mesoporous material.

4. the slag-based mesoporous material described in claim 1 or 2 is for the application of support of the catalyst.