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CN-122010475-A - Low-carbon high-strength building material based on microorganism limited mineralization and preparation method thereof

CN122010475ACN 122010475 ACN122010475 ACN 122010475ACN-122010475-A

Abstract

The invention belongs to the field of cement-free low-carbon high-strength building materials, and particularly relates to a low-carbon high-strength building material based on microorganism finite field mineralization and a preparation method thereof. The preparation method comprises the following steps of S1, dispersing microbial thalli by using mineralized liquid containing urea and mineral salt to obtain dispersion liquid, S2, mixing starch and water, heating and gelatinizing to obtain starch gel, S3, mixing the starch gel, the dispersion liquid and solid particles in proportion, triggering reversible transformation of gel-sol by the starch gel through stirring and inducing, enabling the microbial thalli to be uniformly limited in a gel network in the reversible transformation process of the gel-sol, then placing in a mold, placing for a period of time, and demolding to obtain the microbial thalli. The whole preparation process does not need to use traditional cement, reduces carbon emission and energy consumption, and the compressive strength of the prepared low-carbon high-strength building material can reach 10-27 MPa, thereby meeting the strength requirement of MU10-MU25 in the strength grade of sintered common bricks in national standard GB/T5101-2017.

Inventors

  • WANG SHUTAO
  • LAI JIANKUN
  • XU XUETAO

Assignees

  • 中国科学院理化技术研究所

Dates

Publication Date
20260512
Application Date
20260413

Claims (10)

  1. 1. The preparation method of the low-carbon high-strength building material based on microbial limited-area mineralization is characterized by comprising the following steps of: s1, dispersing microbial thalli by using mineralized liquid containing urea and mineral salt to obtain dispersion liquid; s2, mixing starch with water, and heating and gelatinizing to obtain starch gel; S3, mixing the starch gel, the dispersion liquid and the solid particles in proportion, triggering the reversible transformation of the gel-sol by stirring and inducing the starch gel, enabling microbial cells to be uniformly limited in a gel network in the reversible transformation process of the gel-sol, then placing the microbial cells into a mould for a period of time, and demoulding to obtain the low-carbon high-strength building material based on microbial limited mineralization.
  2. 2. The method of claim 1, wherein the mineral salt is selected from one or more of calcium chloride, calcium nitrate, calcium lactate, magnesium chloride, magnesium nitrate; the microbial thallus is selected from one or more of bacillus barbitarus, bacillus sphaericus, bacillus licheniformis, bacillus cereus, bacillus subtilis and bacillus megaterium; the solid particles are selected from one or more of quartz sand, sea sand, huang Jinsha, pearl sand, desert sand and industrial waste particles.
  3. 3. The method of claim 1, wherein the molar ratio of urea to mineral salt is 1:2 to 2:1; the concentration of microbial cells in the dispersion was 5X 10 7 ~5×10 8 ‌ CFU/mL.
  4. 4. The method according to claim 1, wherein the concentration of urea in the dispersion is 0.25 to 2.5M.
  5. 5. The preparation method of claim 1, wherein the mass ratio of starch to water is 5:95-25:75.
  6. 6. The preparation method of claim 1, wherein the mass ratio of the starch gel to the dispersion is 1:2-2:1.
  7. 7. The preparation method according to claim 1, wherein the mass ratio of the total mass of the starch gel and the dispersion liquid to the solid particles is 1:2.5-3.5.
  8. 8. The preparation method according to claim 1, wherein in the step S3, the stirring speed is 50-600 rpm, and the stirring time is 1-20 min; And in the step S3, the placing time in the die is 12-24 hours.
  9. 9. The method according to claim 1, wherein step S1 further comprises the step of culturing microbial cells in advance: culturing microbial thallus, centrifuging after culturing, and discarding supernatant to obtain the final product; wherein the centrifugal speed is 5000 rpm, the centrifugal time is 5-10 min, and the centrifugal temperature is 4-25 ℃.
  10. 10. A low-carbon high-strength building material based on microbial limited-area mineralization, which is characterized in that the building material is prepared by the preparation method of any one of claims 1-9; The compressive strength of the low-carbon high-strength building material is 10-27 MPa.

Description

Low-carbon high-strength building material based on microorganism limited mineralization and preparation method thereof Technical Field The invention belongs to the field of cement-free low-carbon high-strength building materials, and particularly relates to a low-carbon high-strength building material based on microorganism finite field mineralization and a preparation method thereof. Background The global population urbanization process continues to accelerate since the 21 st century, and the building industry has a rigid growing situation for the market demand for building materials. Although the traditional cement-based building material has the characteristics of excellent mechanical property, low production cost and wide engineering suitability, the large-scale application of the traditional cement-based building material is accompanied with serious resource and environmental problems, and the traditional cement-based building material becomes a core constraint factor for realizing the aim in the building industry. Long-term over exploitation has caused rapid exhaustion of global natural river sand resources, and causes a series of environmental problems such as ecological destruction of river channels, frequent geological disasters and the like. In addition, a large amount of unconventional particle materials such as desert sand, sea sand, metallurgical slag, building rubbish regenerated aggregate and the like in the global scope cannot realize large-scale high-value utilization in the traditional cement-based building material system due to poor interface characteristics and large cementing difficulty, and a large amount of stockpiling occupies land resources and causes serious secondary environmental pollution. In order to reduce the energy consumption and the carbon emission load of the building industry and promote the recycling high-value utilization of non-conventional granular materials, a microorganism-induced calcium carbonate precipitation (MICP) mineralization technology under the conditions of normal temperature and normal pressure is widely focused by researchers at home and abroad in the field of low-carbon building materials. The technology can generate calcium carbonate mineral phases with cementing performance through metabolic activities of functional microorganisms, realizes the consolidation molding of various granular materials, does not need high-temperature calcination in the production process, reduces carbon emission by more than 80 percent compared with the traditional cement-based building materials, can adapt to unconventional aggregates which are difficult to utilize by various traditional processes such as desert sand, industrial solid waste and the like, has obvious ecological benefit and economic benefit, and is one of the technical directions with the most industrialization potential in the field of the current low-carbon building materials. However, the existing MICP mineralization technology still has a core technical bottleneck which is difficult to break through in the large-scale preparation and engineering application of the particle-cemented building material. In the prior art, most of processes do not effectively fix functional microorganisms, thalli are in a free dispersion state in a mineralization reaction system, and can freely migrate and diffuse along with liquid phase in the mineralization liquid circulation and immersion processes, so that directional and localized enrichment and fixation cannot be realized at cementing interfaces among solid particles, calcium carbonate deposition sites are uncontrollable, deposition distribution is uneven, a continuous and compact high-strength cementing structure cannot be formed in particle gaps, mineralization reaction efficiency and cementing effect are greatly reduced, and the mechanical properties of the finally prepared building material product are far lower than those of traditional standard building materials, and cannot meet the application requirements of constructional engineering. Meanwhile, as the free diffusion and mineralization reaction processes of thalli are uncontrollable, the prior art needs to rely on a closed specific die to carry out whole-course constraint on a reaction system and aggregate molding, so that the cementing molding of the particle materials can be realized, the industrial continuous production process can not be adapted, the problems of low production efficiency, poor molding flexibility and high large-scale production cost exist, and the industrial popularization and large-scale engineering application of the technology are severely restricted. In addition, although some of the prior art attempts to fix the thalli by adsorption of organic or inorganic carriers, the problems of poor compatibility between the carrier and the aggregate interface, low thalli loading rate, easy falling off and loss and the like generally exist, and the core bottleneck cannot be fundamentally solved