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CN-117923819-B - Preparation method of high-carbon-fixation high-strength light building material

CN117923819BCN 117923819 BCN117923819 BCN 117923819BCN-117923819-B

Abstract

The invention relates to a preparation method of a high-solid carbon and high-strength light building material, which comprises the following steps of preparing and activating biochar, mixing the biochar with solid waste raw materials to obtain a mixed material, preparing biochar modified lightweight aggregate from the mixed material in a granulator, curing the obtained lightweight aggregate according to the flow of pre-curing, carbonization curing and subsequent wet curing, and drying to obtain the light building material. The invention takes activated biochar as a modified material, takes multi-element solid wastes such as fly ash, coal gangue, desulfurized gypsum and the like as raw materials, takes blast furnace slag as a binder to replace traditional silicone, vinyl Acetate (VAM) emulsion, polyurethane and the like, and takes CO 2 in flue gas discharged by a steelmaking furnace, a cement kiln and a coal-fired power plant for carbonization maintenance, thereby realizing the optimization regulation and control of the internal pore structure of the lightweight aggregate, accelerating the carbonization reaction rate of CO 2 and the inside and outside of an aggregate medium, and effectively improving the integral carbonization degree and CO 2 adsorption performance of the lightweight aggregate.

Inventors

  • SONG MIN
  • SHAN BEI
  • HU YUE
  • HUAN QUN
  • YU LEI

Assignees

  • 东南大学

Dates

Publication Date
20260505
Application Date
20240124

Claims (8)

  1. 1. The preparation method of the high-carbon-fixation high-strength light building material is characterized by comprising the following steps of, The preparation of the biochar comprises the steps of screening biomass raw materials to have the particle size of below 2mm and pyrolyzing the biomass raw materials in a tube furnace to obtain the biochar; The method comprises the steps of (1) immersing the biochar into an activating solution according to a certain proportion, continuously stirring for 11-13 h hours, standing at room temperature for 23-25 hours, then placing the biochar into a 110-130 ℃ oven for drying, cooling to room temperature, washing until the pH value is neutral, vacuum-filtering, placing the biochar into the oven for drying at 100-110 ℃ to obtain modified porous biochar, wherein the activating solution is a KOH solution, the mass concentration is 35-45%, and the mixing ratio of the biochar and the activating solution is 1:4-6; Mixing activated biochar with crushed and ground solid waste raw materials, adhesive and cement, stirring at a high speed in a concrete stirrer for 1.5-2.5min uniformly to obtain a mixed material, dividing the mixed material into two parts, wherein the weight ratio of the first part is 60-80%, the solid waste raw materials comprise fly ash, coal gangue and desulfurized gypsum, and the adhesive is blast furnace slag; preparing biochar modified lightweight aggregate, namely transferring the first part of mixed material into a granulator, spraying deionized water 2-4 min under the condition of the rotating speed of 35-40 rpm to form a granular mixture, uniformly adding the second part of mixture, and automatically forming without water spraying to finally obtain spherical lightweight aggregate of 4.75-16 mm; curing the lightweight aggregate, namely curing the lightweight aggregate according to the flow of pre-curing, carbonization curing and subsequent wet curing, wherein the water content of the lightweight aggregate is controlled to be 11% -15% when the lightweight aggregate is pre-cured before carbonization curing; And (3) drying the lightweight aggregate, namely curing the lightweight aggregate, and then placing the lightweight aggregate into a drying oven for drying to obtain the lightweight building material.
  2. 2. The method for preparing a high-carbon-fixation high-strength lightweight building material according to claim 1, wherein the drying condition of the lightweight aggregate is that the temperature is 60-70 ℃ and the drying time is 11-13h.
  3. 3. The method for producing a high-carbon-fixation high-strength lightweight building material according to claim 1, wherein the lightweight aggregate has a water absorption of 8.76 to 13.29% for 1 hour, a bulk density of 952.63 to 1143.94 kg/m 3 , a barrel pressure strength of 10.13 to 14.16 mpa, and a co 2 absorption of 9.36 wt to 13.15wt%.
  4. 4. The method for preparing the high-carbon-fixation high-strength light building material according to claim 1, wherein the biochar is one or a mixture of a plurality of corn straw biochar, rice straw biochar and wood dust biochar.
  5. 5. The method for producing a high-carbon-content high-strength lightweight building material according to claim 1, wherein the ratio of solid waste raw material to cement is 3-5:1.
  6. 6. The high-carbon-content high-strength light building material prepared by the preparation method according to any one of claims 1 to 5, wherein the weight proportion of the components of the light building material is that 20 parts of cement, 40 to 60 parts of fly ash, 10 to 20 parts of coal gangue and 10 to 20 parts of desulfurized gypsum, the weight proportion of blast furnace slag is 5wt to 10 weight percent of the sum of the weight of solid waste raw materials and cement, and the weight proportion of the activated biochar is 1 to wt to 7 weight percent of the sum of the weight of the solid waste raw materials and cement.
  7. 7. The high solids high strength lightweight construction material of claim 6, wherein the activated biochar is present in a weight ratio of 3% wt% to 7% by weight of the sum of the weight of solid waste material and cement.
  8. 8. The use of a high carbon number high strength lightweight building material as claimed in claim 7 as lightweight aggregate for the preparation of concrete.

Description

Preparation method of high-carbon-fixation high-strength light building material Technical Field The invention relates to the technical field of mineralization of carbon dioxide, in particular to a preparation method of a high-carbon-fixation high-strength light building material. Background Carbon sequestration and utilization are important ways for constructing clean low-carbon energy systems in China, and CO 2 mineralization technology is an important component for carbon sequestration and utilization. It mimics and accelerates the natural process of silicate mineral weathering, the most active compounds commonly used for CO 2 mineralization being the oxides of the divalent metals Ca and Mg, i.e. CO 2 reacts with calcium oxide (CaO) and magnesium oxide (MgO) to form carbonates. The carbonate produced during carbonation is chemically stable and allows nearly permanent storage of CO 2. And the reaction process is a spontaneous exothermic reaction, which is thermodynamically favourable. At present, china has become one of the largest solid waste producing countries in the world, the treatment pressure of industrial solid waste is huge, and the recycling utilization of the industrial solid waste is needed in the process of treating a large amount of solid waste. Most industrial solids deserted city are rich in CaO and MgO, have good mineralization activity, and because these wastes are derived from industrial processes and are also closer to CO 2 emissions sources, the potential for large scale mineralization of CO 2 with industrial solid wastes is enormous. The light building material becomes one of the main digestion carriers of the industrial solid waste at present, and the CO 2 mineralization maintenance solid waste building material is used as an emerging CO 2 utilization technology, so that the large-scale CO 2 sealing and emission reduction and solid waste treatment are expected to be realized. The biochar is a carbon-negative material produced by thermochemical conversion of various biomass wastes such as straw and the like in an anoxic environment, has the capacity of reducing emission of 12% of global CO 2, and can not only realize double carbon emission reduction, but also effectively promote the diffusion rate of CO 2, obviously promote the absorption rate and the sealing rate of CO 2 and greatly shorten the carbonization maintenance time by adding the biochar into CO 2 mineralization of solid wastes. In the existing preparation method of the light building material, in the mineralization and maintenance process of CO 2, as carbonization is carried out, the formation of calcium carbonate is increased, so that the microstructure is more compact, and CO 2 is prevented from diffusing into the agglomerates from the environment. This process eventually slows down the rate of post-carbonization, limiting the increase in carbonization of the lightweight aggregate, particularly the core portion of the aggregate. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a preparation method of a high-carbon-fixation high-strength light building material, which aims to regulate and control the pore structure of an aggregate formed in the preparation process through porous biochar, accelerate the carbonization reaction of CO 2 and calcium-and magnesium-containing mineral components inside and outside the aggregate through the adsorption property of the biochar on CO 2 so as to improve the absorption mineralization capacity and carbonization degree of the CO 2 on subsequent CO 2 and finally improve the performance of a finished product. The technical scheme adopted by the invention is as follows: the preparation method of the high-solid carbon and high-strength light building material comprises screening biomass raw materials to below 2mm, and pyrolyzing by a tube furnace to obtain biochar; The method comprises the steps of (1) immersing the biochar into an activating solution according to a certain proportion, continuously stirring for 11-13 h, standing for 23-25 h at room temperature, putting into a 110-130 ℃ oven for drying, cooling to room temperature, eluting with hydrochloric acid, washing with deionized water until the pH value is neutral, vacuum-filtering, and putting into the oven for drying at 100-110 ℃ to obtain modified porous biochar; Mixing activated biochar with crushed and ground solid waste raw materials, an adhesive and cement, stirring at a high speed in a concrete stirrer for 1.5-2.5 min uniformly to obtain a mixed material, dividing the mixed material into two parts, wherein the weight ratio of the first part is 60-80%, the solid waste raw materials comprise fly ash, coal gangue and desulfurized gypsum, and the adhesive is blast furnace slag; Preparing biochar modified lightweight aggregate, namely transferring the first part of mixed material into a disc granulator, spraying deionized water for 2-4 min under the condition of the rotating speed of 35-