CN103920457A - Method for preparing geopolymer adsorption material by using Bayer process red mud - Google Patents

Abstract

The invention discloses a method for preparing geopolymer adsorption material by using Bayer process red mud. Dry the kaolin and red mud separately, calcined the kaolin and ball-milled the red mud, then mixed the red mud and calcined kaolin at a mass ratio of 3:7~6:4, put them in a stirring pot, and added a modulus of 1.5 Stir the water glass solution evenly, so that the mass of sodium oxide in the water glass solution is 8% of the total mass of the mixture of calcined kaolin and red mud, and the water-cement ratio of the slurry is 0.35~0.38; put appropriate amount of aluminum powder and soap powder into a small amount of water, and disperse After uniformity, add to the slurry obtained above, and then stir evenly; after waiting for 3 to 5 minutes, put the expanded slurry into a mold, put the mold in an oven or remove the mold and put it in an oven for curing, and the geopolymer is obtained Adsorbent material. The method of the invention has simple process equipment, low cost, is easy to popularize, and is less affected by the environment. The produced geopolymer material has uniform pores and high strength, and can be reused after acid treatment.

Description

Method for preparing geopolymer adsorption material by using Bayer process red mud

technical field

The invention belongs to the technical field of preparation of inorganic non-metallic materials, and in particular relates to a method for preparing geopolymer adsorption materials by using Bayer process red mud. the

Background technique

Geopolymer materials are completely different from Portland cement in terms of mineral composition. It is composed of amorphous minerals, and its main raw material is highly active metakaolin; alkaline activators (caustic potash, caustic soda, water glass, potassium silicate etc.); hardening accelerator (calcium silicate and silica fume with low calcium-silicon ratio, all of which are amorphous); admixture (mainly retarder). After entering the 1990s, the selection range of raw materials and activators has been greatly expanded, and the sources of silicon-alumina raw materials have been expanded to four categories: volcanic zeolite, fly ash, mineral waste residue, and burnt clay; activators include single alkali metals, alkaline earth metals, and hydroxides. Extended to oxides, halides, organic components, etc. as activators, a class of inorganic non-metallic materials formed by batching, mixing, stirring with water, and forming through hydration polymerization and dehydration hardening within a certain period of time. the

In recent years, a large number of patents on geopolymers have emerged at home and abroad, but there are very few patents on geopolymer adsorption materials. The patent number is 200910114099, and the Chinese patent publication number is 101560071, which discloses a phosphoric acid-based geopolymer porous material and its preparation method. Because the addition of more alumina increases the cost, and it lacks an efficient adsorption medium, the adsorption efficiency It remains to be discussed; the patent number is 200710200202.0, and the Chinese patent with the publication number CN101053826 discloses a geopolymer adsorbent and its preparation method. Fiber, silica gel, activated alumina, etc. are very expensive and are not suitable for the treatment of industrial sewage. the

Red mud is the slag produced by leaching alumina from bauxite with strong alkali, and the main treatment method for red mud is to stack it on the seabed or on land. With the rapid development of the aluminum smelting industry, the amount of red mud discharged from the production of alumina is also increasing, and a series of problems caused by stockpiling and disposal are becoming more and more serious, causing serious environmental problems. At present, the treatment of red mud is mainly used for building materials and extracting useful substances from it. After a lot of experimental research, the application of sintered red mud in building materials has entered the stage of large-scale production, and has accumulated decades of production experience , while the comprehensive utilization of Bayer process red mud has no substantive progress. the

Regarding the Bayer process red mud, many scholars have studied its ability to adsorb heavy metal ions in recent years, and all have achieved relatively ideal experimental results, and the porous foamed geopolymer matrix also has a good ability to fix heavy metal ions. In the geopolymer structure, red mud is mainly used as a filler except for a small amount of participation in the geopolymerization reaction. Therefore, there are a large number of red mud particles in the geopolymer, which can be used as a good adsorption medium. The water glass activator has strong alkalinity, and it is easy to react with aluminum powder to produce a large number of bubbles, so that the prepared material has a porous structure, and the porous geopolymer matrix has a good ability to fix heavy metal ions. The invention effectively combines the red mud of the Bayer process with the porous substrate of the geopolymer, and achieves a relatively ideal effect. the

Contents of the invention

The purpose of the present invention is to provide a method for preparing geopolymer adsorption material by using Bayer process red mud. This method uses Bayer red mud to make high-efficiency, low-cost and environmentally friendly geopolymer adsorption materials, and can be widely used in the treatment of industrial wastewater containing heavy metal ions, reducing the land resources occupied by red mud stacking, turning waste into treasure, and reducing environmental pollution. pollute. the

The specific steps are:

(1) Dry the kaolin and red mud separately until the water content is less than 1%, then calcinate the kaolin at 800°C for 6 hours and then ball mill until the specific surface area is 800±1m ² /Kg, and ball mill the red mud until the specific surface area is 400 ±1m ² /Kg.

(2) Mix the red mud treated in step (1) with the calcined kaolin treated in step (1) at a mass ratio of 3:7 to 6:4. the

(3) Utilize chemically pure NaOH to transfer high-modulus industrial water glass to a water glass solution with a modulus of 1.5. the

(4) the mixture that step (2) is made is placed in stirring pot, then add the water glass solution that the modulus that a certain amount of step (3) makes is 1.5, make the sodium oxide quality in the water glass solution be step ( 2) The total mass of the prepared mixture is 8%, the slurry water-cement ratio is 0.35~0.38, and the mixture is evenly stirred. the

(5) Get the aluminum powder that accounts for 0.03～0.08 wt% of the mixture gross mass that step (2) makes, the anionic surfactant that accounts for the mixture gross mass 0.002～0.005 wt% that step (2) makes is put into a small amount of water, After dispersing evenly, add it to the slurry obtained in step (4), stir evenly, then wait for 3~5 minutes, put the expanded slurry into a mold, and put the mold into an oven at 60~80°C for 5~ After curing for 7 hours or at room temperature, demoulding and placing in an oven at 50±5°C under vacuum conditions for curing for 36-72 hours, the geopolymer adsorption material is obtained. the

The anionic surfactant is soap powder. the

The method of the invention has simple process, requires less equipment, can process red mud of Bayer process in large quantities, is low in cost, has strong spreadability, and is less affected by the environment. It is an effective method to turn waste into treasure. In addition, the geopolymer adsorption material prepared by the method of the present invention has uniform pores and high strength, and can be reused after acid treatment. the

Detailed ways

The red mud raw materials used in the following examples were collected from Guangxi Pingguo Aluminum Co., Ltd. the

Example 1:

(1) Dry the kaolin and red mud to a moisture content of 0.8% first, then calcinate the kaolin at 800°C for 6 hours, then ball mill it to a specific surface area of 800m ² /Kg, and ball mill the red mud to a specific surface area of 400m ² /Kg Kg.

(2) Mix the red mud treated in step (1) with the calcined kaolin treated in step (1) at a mass ratio of 3:7. the

(3) Utilize chemically pure NaOH to transfer high-modulus industrial water glass to a water glass solution with a modulus of 1.5. the

(4) the mixture that step (2) is made is placed in stirring pot, then add the water glass solution that the modulus that a certain amount of step (3) makes is 1.5, make the sodium oxide quality in the water glass solution be step ( 2) 8% of the total mass of the prepared mixture, the water-cement ratio of the slurry is 0.36, and the mixture is evenly stirred. the

(5) get the aluminum powder that accounts for 0.05 wt% of the mixture gross mass that step (2) makes, the anionic surfactant (soap powder) that accounts for 0.004 wt% of the mixture gross mass that step (2) makes is put into a small amount of water, After dispersing evenly, add it to the slurry obtained in step (4), stir evenly, then wait for 4 minutes, put the expanded slurry into a mold, and remove it after curing at room temperature. The obtained test piece is wrapped in plastic wrap and placed in an oven at 50°C After curing for 48 hours, the geopolymer adsorption material is obtained. the

Example 2:

(1) Dry the kaolin and red mud to a moisture content of 0.5% respectively, then calcinate the kaolin at 800°C for 6 hours, then ball mill it to a specific surface area of 800m ² /Kg, and ball mill the red mud to a specific surface area of 400m ² /Kg Kg.

(2) Mix the red mud treated in step (1) with the calcined kaolin treated in step (1) at a mass ratio of 1:1. the

(3) Utilize chemically pure NaOH to transfer high-modulus industrial water glass to a water glass solution with a modulus of 1.5. the

(4) the mixture that step (2) is made is placed in stirring pot, then add the water glass solution that the modulus that a certain amount of step (3) makes is 1.5, make the sodium oxide quality in the water glass solution be step ( 2) 8% of the total mass of the prepared mixture, the water-cement ratio of the slurry is 0.36, and the mixture is evenly stirred. the

(5) get the aluminum powder that accounts for 0.06 wt% of the mixture gross mass that step (2) makes, the anionic surfactant (soap powder) that accounts for 0.003 wt% of the mixture gross mass that step (2) makes is put into a small amount of water, After dispersing evenly, add it to the slurry obtained in step (4), stir evenly, then wait for 4 minutes, put the expanded slurry into a mold, then wrap it in a plastic bag and tie it tightly, then put the mold into an oven at 70°C under vacuum conditions After curing for 6 hours, take it out and demould, and then the geopolymer adsorption material is obtained. the

The geopolymer adsorption material prepared in the above examples has a stable compressive strength of 2-5 MPa, a porosity of 30-70%, a bulk density of 0.6-1.4 g/m ³ , and high adsorption efficiency. , copper, chromium, cadmium and other ion adsorption efficiency is above 99.9%, and can be reused many times after being treated with a certain concentration of acid solution.

Claims (1)

1. A method utilizing Bayer process red mud to prepare geopolymer adsorption material is characterized in that the specific steps are: (1) Dry the kaolin and red mud separately until the water content is less than 1%, then calcinate the kaolin at 800°C for 6 hours and then ball mill until the specific surface area is 800±1m ² /Kg, and ball mill the red mud until the specific surface area is 400 ±1m ² /Kg; (2) mixing the red mud treated in step (1) with the calcined kaolin treated in step (1) in a mass ratio of 3:7 to 6:4; (3) utilize chemically pure NaOH to adjust the industrial water glass of high modulus to the water glass solution that modulus is 1.5; (4) the mixture that step (2) is made is placed in stirring pot, then add the water glass solution that the modulus that a certain amount of step (3) makes is 1.5, make the sodium oxide quality in the water glass solution be step ( 2) 8% of the total mass of the prepared mixture, the water-cement ratio of the slurry is 0.35~0.38, and the mixture is evenly stirred; (5) Get the aluminum powder that accounts for 0.03～0.08 wt% of the mixture gross mass that step (2) makes, the anionic surfactant that accounts for the mixture gross mass 0.002～0.005 wt% that step (2) makes is put into a small amount of water, After dispersing evenly, add it to the slurry obtained in step (4), stir evenly, then wait for 3~5 minutes, put the expanded slurry into a mold, put the mold into an oven at 60~80°C for 5~ After 7 hours or room temperature curing, demould and place in an oven at 50±5°C under vacuum for 36-72 hours, the geopolymer adsorption material is obtained; The anionic surfactant is soap powder.