阅读说明：本技术 利用fcc废催化剂与赤泥耦合制备地质聚合物的方法 (Method for preparing geopolymer by coupling FCC (fluid catalytic cracking) waste catalyst and red mud ) 是由 倪红卫 张华� 李杨 余丽 何环宇 于 2020-06-17 设计创作，主要内容包括：本发明提供了一种利用FCC废催化剂与赤泥耦合制备地质聚合物的方法。本发明将FCC废催化剂与烧结法赤泥进行混合,通过调控原料配比调节钙铝比为0.3～0.8,同时通过添加硅灰调节硅铝比为1.8～2.2,然后与复合碱激发剂混合后注入模具中,经成模、固化、脱模和养护处理,得到高强度地质聚合物。本发明不仅能够有效的固化FCC废催化剂中的重金属,而且由于将钙含量相对较高的烧结法赤泥与FCC废催化剂联用,能够有效调控混合料激发凝胶的聚合和固结硬化过程,从而提高地质聚合物的抗压强度。如此,既解决了环境污染和土地资源占用等问题,又实现了固体废弃物资源化利用的目标。(The invention provides a method for preparing a geopolymer by coupling FCC waste catalyst and red mud. The method comprises the steps of mixing FCC spent catalyst with red mud obtained by a sintering method, adjusting the calcium-aluminum ratio to 0.3-0.8 by regulating the raw material ratio, adjusting the silicon-aluminum ratio to 1.8-2.2 by adding silica fume, mixing with a composite alkali activator, injecting into a mold, molding, curing, demolding and maintaining to obtain the high-strength geopolymer. The invention not only can effectively solidify heavy metals in the FCC waste catalyst, but also can effectively regulate and control the polymerization and consolidation hardening processes of the mixture excited gel due to the combination of the sintering process red mud with relatively high calcium content and the FCC waste catalyst, thereby improving the compressive strength of the geopolymer. Therefore, the problems of environmental pollution, land resource occupation and the like are solved, and the aim of resource utilization of the solid waste is fulfilled.)

1. A method for preparing geopolymer by coupling FCC spent catalyst and red mud is characterized by comprising the following steps:

s1, mixing FCC waste catalyst and red mud powder to obtain a mixed powdery material A with a calcium-aluminum molar ratio of 0.3-0.8;

s2, adding silica fume into the mixed powdery material A obtained in the step S1 to obtain a mixed powdery material B with the silicon-aluminum molar ratio of 1.8-2.2;

s3, mixing the components in a mass ratio of 1: (1.5-2.2) mixing and stirring the composite alkali activator and the mixed powder material B obtained in the step S2 to obtain a mixed material excited gel;

and S4, injecting the mixture excited gel obtained in the step S3 into a mold, and performing molding, curing, demolding and maintaining treatment to obtain the geopolymer.

2. The method for preparing geopolymer by coupling FCC spent catalyst with red mud according to claim 1, wherein in step S1, the red mud is sintering process red mud.

3. The method for preparing geopolymer by coupling FCC spent catalyst and red mud according to claim 2, wherein the sintering process red mud comprises the following main components: SiO 2₂15-25 wt% of Al₂O₃The content of (B) is 7.5-15 wt%, and the content of CaO is 35-45 wt%.

4. The method for preparing geopolymer by coupling FCC spent catalyst with red mud according to claim 1, wherein in step S1, the main components of the FCC spent catalyst are: SiO 2₂30-40 wt% of Al₂O₃The content of (b) is 50-60 wt%, and the particle size of the FCC spent catalyst is less than 0.2 mm.

5. The method for preparing geopolymer by coupling FCC spent catalyst with red mud according to claim 1, wherein in step S1, the mass ratio of FCC spent catalyst to red mud is 40%: 60% -60%: 40 percent; the molar ratio of calcium to aluminum in the mixed powdery material A is preferably 0.5-0.6.

6. The method for preparing geopolymer by coupling FCC spent catalyst and red mud according to claim 1, wherein in step S2, SiO in the silica fume₂Is more than 90 wt%, and the particle size of the silica fume is less than 0.054 mm.

7. The method for preparing geopolymer by coupling FCC spent catalyst with red mud according to claim 1, wherein in step S3, the composite alkali activator comprises sodium hydroxide and water glass.

8. The method for preparing geopolymer by coupling FCC spent catalyst and red mud according to claim 7, wherein the mass ratio of sodium hydroxide to water glass is 1: 4.8, the modulus of the composite alkali activator is controlled to be 1.2.

9. The method for preparing geopolymer by coupling FCC spent catalyst with red mud according to claim 1, wherein the operation of step S4 is as follows: injecting the mixture excited gel obtained in the step S3 into a mold twice, and vibrating the mixture excited gel on a compaction table for 50-80 times when the mixture excited gel is added once; then covering a preservative film on the mixture excited gel and the mould together, curing for 4-24 hours at 40-85 ℃, and demoulding; and finally, continuously maintaining for 3-7 days under the conditions that the temperature is 20-25 ℃ and the humidity is more than 90% to obtain the geopolymer.

10. A geopolymer prepared by coupling FCC spent catalyst with red mud, characterized in that it is prepared by the process according to any one of claims 1 to 9.

Technical Field

The invention belongs to the technical field of solid waste resource utilization, and particularly relates to a method for preparing a geopolymer by coupling an FCC (fluid catalytic cracking) waste catalyst and red mud.

Background

Fluid Catalytic Cracking (FCC) is one of the most important conversion processes in petroleum refineries, and FCC catalysts play an important role in the process. As crude oil is increasingly heavy, deteriorated and the FCC catalyst is continuously recycled, metals deposited on the FCC catalyst are gradually increased, resulting in a decrease in both activity and heavy oil conversion capacity, forming a spent FCC catalyst. Although the FCC spent catalyst loses catalytic activity, most of the internal molecular sieve structure of the FCC spent catalyst is complete, and the FCC spent catalyst still has certain utilization value. Metals such as Ni, V, Fe and the like are main elements causing the poisoning of the FCC catalyst, and the severely poisoned FCC catalyst is generally difficult to regenerate. At present, domestic and foreign research institutions mainly recycle valuable components in the FCC spent catalyst, such as heavy metal, aluminum oxide, rare earth elements, molecular sieves and the like, but the FCC spent catalyst has low content of heavy metal, rare earth elements and the like, so that the extraction economic value is low, a large amount of acid and alkali solution is consumed in the recovery process, the recovery cost is high, and secondary pollution is easily caused. Therefore, effective treatment and utilization of the FCC spent catalyst has become a very important issue.

The red mud is solid waste residue discharged when aluminum oxide is extracted in the aluminum production industry, and is a strong alkaline substance which has pollution to the environment. The red mud can be divided into 3 types of Bayer process red mud, sintering process red mud and combination process red mud according to the production method, wherein CaO and SiO in the sintering process red mud₂High in content, mainly including dicalcium silicate, calcite, perovskite, magnetite and monazite. 1.0-1.8 tons of red mud is generated when 1 ton of alumina is produced, about 40 hundred million tons of red mud is discharged in total in the world as 2017 years, the annual discharge amount of 1.2 million tons is increased, and the red mud is discharged in large countries in China, and about 6000 million tons of red mud are discharged in each year. At present, the large amount of earth is occupied by damming and stockpiling, and a large amount of alkali liquor is discharged to rivers or open air to be stockpiled, and the alkali liquor permeates and dust fliesBoth constitute a pollution to air, water resources and the like.

For example, chinese patent CN110818332A discloses a method for preparing a calcium-free system geopolymer by coupling FCC waste catalyst and silica fume, which comprises mixing FCC waste catalyst and silica fume with a compound alkali activator, and curing to obtain a calcium-free system geopolymer with high strength, thereby realizing resource utilization of two solid wastes. However, the method is directed to a calcium-free system geopolymer and is not suitable for utilizing calcium-containing system solid waste. Chinese patent CN106477985A discloses a red mud geopolymer material formula and a preparation method thereof, and the red mud geopolymer material formula is prepared by mixing red mud, fly ash and a composite alkali activator and then curing. However, the method does not carry out targeted limitation and research on the content of components in the red mud and the fly ash, particularly the content of calcium, and is not suitable for the method for preparing the geopolymer by using the FCC catalyst and the red mud. Therefore, the resource utilization of the FCC spent catalyst and the red mud becomes a problem to be solved urgently.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a method for preparing a geopolymer by coupling an FCC waste catalyst and red mud, the FCC waste catalyst and the sintering red mud are mixed, the calcium-aluminum ratio is adjusted by adjusting and controlling the proportion, the silicon-aluminum ratio is adjusted by silica fume, and the high-strength geopolymer is obtained by curing under the action of a composite alkali activator, so that heavy metals in the FCC waste catalyst are effectively cured, the problems of environmental pollution, land resource occupation and the like are solved, and the aim of recycling solid wastes is fulfilled.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a method for preparing geopolymer by coupling FCC spent catalyst and red mud comprises the following steps:

s1, mixing FCC waste catalyst and red mud powder to obtain a mixed powdery material A with a calcium-aluminum molar ratio of 0.3-0.8;

s2, adding silica fume into the mixed powdery material A obtained in the step S1 to obtain a mixed powdery material B with the silicon-aluminum molar ratio of 1.8-2.2;

s3, mixing the components in a mass ratio of 1: (1.5-2.2) mixing and stirring the composite alkali activator and the mixed powder material B obtained in the step S2 to obtain a mixed material excited gel;

and S4, injecting the mixture excited gel obtained in the step S3 into a mold, and performing molding, curing, demolding and maintaining treatment to obtain the geopolymer.

Further, in step S1, the red mud is sintered red mud.

Further, the main components in the sintering process red mud are as follows: SiO 2₂15-25 wt% of Al₂O₃The content of (B) is 7.5-15 wt%, and the content of CaO is 35-45 wt%.

Preferably, the main components in the sintering process red mud are as follows: SiO 2₂20-24 wt% of Al₂O₃The content of (A) is 10-12 wt%, and the content of CaO is 38-42 wt%.

Further, in step S1, the main components of the FCC dead catalyst are: SiO 2₂30-40 wt% of Al₂O₃The content of (b) is 50-60 wt%, and the particle size of the FCC spent catalyst is less than 0.2 mm.

Further, in step S1, the mass ratio of the FCC dead catalyst to the red mud is 40%: 60% -60%: 40 percent; in the mixed powdery material A, the molar ratio of calcium to aluminum is 0.3-0.8.

Further, in step S2, SiO in the silica fume₂Is more than 90 wt%, and the particle size of the silica fume is less than 0.054 mm.

Further, in step S3, the composite alkali activator includes sodium hydroxide and water glass.

Further, the mass ratio of the sodium hydroxide to the water glass is 1: 4.8, the modulus of the composite alkali activator is controlled to be 1.2.

Preferably, in step S3, the mass ratio of the composite alkali activator to the mixed powdery material B obtained in step S2 is 1: 2.

further, the operation of step S4 is as follows: injecting the mixture excited gel obtained in the step S3 into a mold twice, and vibrating the mixture excited gel on a compaction table for 50-80 times when the mixture excited gel is added once; then covering a preservative film on the mixture excited gel and the mould together, curing for 4-24 hours at 40-85 ℃, and demoulding; and finally, continuously maintaining for 3-7 days under the conditions that the temperature is 20-25 ℃ and the humidity is more than 90% to obtain the geopolymer.

The invention also provides a geopolymer prepared by coupling the FCC spent catalyst and the red mud, and the geopolymer is prepared by the preparation method.

Advantageous effects

Compared with the prior art, the method for preparing the geopolymer by coupling the FCC spent catalyst and the red mud has the following beneficial effects:

(1) according to the method for preparing the geopolymer by coupling the FCC spent catalyst and the red mud, the FCC spent catalyst and the red mud are used as main silicon-aluminum raw materials, the silica fume is used as a silicon correction material, and a mixture of sodium hydroxide and water glass is used as a composite alkali activator, so that the reaction can quickly generate C-A-S-H gel, and the obtained geopolymer has quick-setting property and simultaneously shows higher strength. The heavy metal in the FCC waste catalyst can be effectively solidified, and the sintering process red mud with relatively high calcium content is combined with the FCC waste catalyst, so that the polymerization and consolidation hardening processes of the mixture excited gel can be effectively regulated and controlled, and the compressive strength of the geopolymer is improved. Therefore, the problems of environmental pollution, land resource occupation and the like are solved, the aim of resource utilization of the solid waste is fulfilled, and the method has good economic benefit and environmental protection benefit.

(2) According to the method for preparing the geopolymer by coupling the FCC waste catalyst and the red mud, the FCC waste catalyst and the sintering-process red mud with high calcium content are selected as raw materials of the geopolymer, and the high-strength geopolymer can be obtained by adjusting the calcium-aluminum ratio and the silicon-aluminum ratio in the raw materials within the range defined by the invention, so that the leaching toxicity of heavy metals is remarkably reduced, the recovery and reutilization of the FCC waste catalyst and the red mud are realized, the recovery cost is low, and the recovery effect is remarkable.

(3) The method for preparing the geopolymer by coupling the FCC waste catalyst and the red mud has the advantages of simple process, environmental friendliness and low production cost, can reasonably utilize the FCC waste catalyst and the red mud, has good compressive strength, can be widely applied to building engineering materials, sealing materials, high-temperature-resistant materials and the like, and realizes the purpose of changing waste into valuable.

Detailed Description

The technical solutions of the embodiments of the present invention will be described clearly and completely below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments; all other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

The method for preparing the geopolymer by coupling the FCC spent catalyst and the red mud comprises the following steps:

s1, mixing the FCC spent catalyst and the red mud powder to obtain a mixed powdery material A with the calcium-aluminum molar ratio of 0.3-0.8.

Wherein, the red mud is preferably sintering process red mud. The sintering method red mud comprises the following main components: SiO 2₂15-25 wt% of Al₂O₃The content of (B) is 7.5-15 wt%, and the content of CaO is 35-45 wt%.

Preferably, the main components in the sintering process red mud are as follows: SiO 2₂20-24 wt% of Al₂O₃The content of (A) is 10-12 wt%, and the content of CaO is 38-42 wt%. The sintering red mud has high content of calcium oxide and silicon dioxide and relatively low content of aluminum oxide, and is exactly complementary with the FCC waste catalyst component. Meanwhile, the sintering method red mud has the component content within the component range limited by the invention, especially in the preferred range, is combined with the FCC waste catalyst as the raw material of the geopolymer, and is beneficial to adjusting the calcium-aluminum ratio and the silicon-aluminum ratio in the raw material, so that the high-strength geopolymer can be obtained, and not only can the high-strength geopolymer be obtainedEffectively solidify heavy metals and reasonably utilize solid wastes.

The main components in the FCC spent catalyst are as follows: SiO 2₂30-40 wt% of Al₂O₃The content of (b) is 50-60 wt%, and the particle size of the FCC spent catalyst is less than 0.2 mm. The FCC spent catalyst contains heavy metals such as Ni and V and rare earth elements, and the heavy metals and the rare earth elements can be effectively solidified in the geopolymer by preparing the geopolymer, so that the leaching toxicity of the geopolymer is reduced.

The mass ratio of the FCC spent catalyst to the red mud is 40%: 60% -60%: 40 percent; in the mixed powdery material A, the molar ratio of calcium to aluminum is 0.3-0.8. In the actual preparation process, the main component compositions of the FCC spent catalyst and the red mud are firstly determined, then the FCC spent catalyst and the red mud are weighed according to the set calcium-aluminum molar ratio, and in the preferred calcium-aluminum molar ratio range, the intensity of the geopolymer is better, and the leaching toxicity of heavy metals is lower.

S2, adding silica fume into the mixed powdery material A obtained in the step S1 to obtain a mixed powdery material B with the silicon-aluminum molar ratio of 1.8-2.2.

SiO in the silica fume₂Is more than 90 wt%, and the particle size of the silica fume is less than 0.054 mm. By adding silica fume, performing siliceous correction, and adjusting the molar ratio of silicon to aluminum to be 1.8-2.2, the formation of stable Si-O-Al chemical bonds is facilitated, and the high-strength geopolymer with a three-dimensional network structure is obtained.

S3, mixing the components in a mass ratio of 1: and (1.5-2.2) mixing and stirring the composite alkali activator and the mixed powder material B obtained in the step S2 to obtain a mixed material excited gel.

Preferably, the mass ratio of the composite alkali activator to the mixed powdery material B obtained in step S2 is 1: 2.

The composite alkali activator comprises sodium hydroxide and water glass, wherein the mass ratio of the sodium hydroxide to the water glass is 1: 4.8, the modulus of the composite alkali activator is controlled to be 1.2.

And S4, injecting the mixture excited gel obtained in the step S3 into a mold, and performing molding, curing, demolding and maintaining treatment to obtain the geopolymer. The specific operation is as follows:

injecting the mixture excited gel obtained in the step S3 into a mold twice, and vibrating the mixture excited gel on a compaction table for 50-80 times when the mixture excited gel is added once; then covering a preservative film on the mixture excited gel and the mould together, curing for 4-24 hours at 40-85 ℃, and demoulding; and finally, continuously maintaining for 3-7 days under the conditions that the temperature is 20-25 ℃ and the humidity is more than 90% to obtain the geopolymer.

Therefore, the invention can mix the FCC spent catalyst and the red mud to prepare the high-strength geopolymer through simple alkali excitation and low-temperature maintenance, and has simple process and low production cost. The prepared geopolymer can be used for building materials, sealing materials, high-temperature-resistant materials and the like, so that the effective utilization of solid wastes is realized.