CN-118206349-B - Full-solid waste phosphogypsum-based aggregate and preparation method and application thereof

CN118206349BCN 118206349 BCN118206349 BCN 118206349BCN-118206349-B

Abstract

The invention discloses a full-solid waste phosphogypsum-based aggregate, and a preparation method and application thereof, and belongs to the technical field of building material artificial aggregates. The method comprises the steps of adding water into a granulating material, pre-stirring to obtain a premix, granulating the premix to obtain water-drop-shaped raw balls, continuously adding the granulating material or a reconstruction material into the water-drop-shaped raw balls, reconstructing the water-drop-shaped raw balls, continuously granulating to obtain capillary-shaped raw balls, and curing the capillary-shaped raw balls to obtain the full-solid waste phosphogypsum-based aggregate. In addition, the granulating material or the reconstruction material is added to reconstruct the water-drop green balls, thereby not only simplifying the process, but also obviously improving the adaptability of aggregate and silicate cement.

Inventors

SUN TAO
OuYang Gaoshang
WANG ZIYAN
XU DONG
YE ZHIYI

Assignees

武汉理工大学

Dates

Publication Date: 20260512
Application Date: 20240312

Claims (7)

1. The preparation method of the full solid waste phosphogypsum-based aggregate is characterized by comprising the following steps: adding water into the granulating material, pre-stirring to obtain a premix, and granulating the premix to obtain water-drop green pellets; Continuously adding a reconstruction material into the water-drop green pellets, reconstructing the water-drop green pellets, and then continuously granulating to obtain capillary green pellets; Curing the capillary green pellets to obtain the full-solid waste phosphogypsum-based aggregate; Wherein the granulating material comprises 70-85% of phosphogypsum, 10-25% of solid waste silicon-aluminum material and 1-20% of solid waste alkali excitant by mass percent, and the reconstructing material comprises 0-20% of phosphogypsum, 60-90% of solid waste silicon-aluminum material and 1-20% of solid waste alkali excitant by mass percent; In the preparation process of the water-drop green balls, the water-material ratio of the water to the granulating material is (0.17-0.21): 1, the pre-stirring is carried out in a stirrer, and the granulating comprises the steps of putting a premix containing 60-80 parts of the granulating material into a centrifugal granulator for granulating for 3-10min, wherein the rotation rate of the centrifugal granulator is 20-45r/min; In the preparation process of the capillary green pellets, 20-40 parts of reconstruction materials are continuously added into the water drop green pellets, and the granulation comprises 4-10min.
2. The method for preparing the full solid waste phosphogypsum-based aggregate according to claim 1, which is characterized in that when 20-40 parts of reconstruction materials are continuously added into the water drop green balls, capillary core-shell green balls are obtained, the capillary core-shell green balls are subjected to sealing and fresh-keeping for 1-3d, and then are immersed in water for continuous curing for 13-27d or are immersed in sodium silicate curing liquid with the mass concentration of 3-15% for continuous curing for 6-27d, so that the core-shell full solid waste phosphogypsum-based aggregate is obtained.
3. The method for preparing a total solid waste phosphogypsum-based aggregate according to any one of claims 1 to 2, wherein the phosphogypsum is an undisturbed silt or wet agglomerate, the water content is 0-15%, the solid content is not less than 85%, and the content of soluble P impurity and F impurity is not more than 3%.
4. The method for producing a total solid waste phosphogypsum-based aggregate according to any one of claims 1 to 2, wherein said solid waste silica alumina material comprises granulated blast furnace slag of grade S95 or more and at least one of high calcium fly ash of grade II or more or granulated yellow phosphorus slag of grade L95, wherein the CaO content in said high calcium fly ash is more than 10%, and said granulated blast furnace slag of grade S95 or more, said high calcium fly ash of grade II or more and granulated yellow phosphorus slag of grade L95 are each subjected to a screen of 200 mesh or more.
5. The method for preparing a total solid waste phosphogypsum-based aggregate according to any one of claims 1-2, wherein the solid waste alkali activator comprises at least one of grade II or more steel slag powder, carbide slag and red mud, wherein the CaO content in the carbide slag is more than or equal to 65%, the pH value of the red mud is more than 10, the na 2 O content is more than 5%, and the grade II or more steel slag powder, carbide slag and red mud are all processed by a screen of 100 meshes or more.
6. An all-solid waste phosphogypsum-based aggregate prepared by the preparation method of any one of claims 1 to 5.
7. The use of the all-solid waste phosphogypsum-based aggregate of claim 6 in the preparation of concrete products.

Description

Full-solid waste phosphogypsum-based aggregate and preparation method and application thereof Technical Field The invention belongs to the technical field of artificial aggregates of building materials, and particularly relates to a full-solid waste phosphogypsum-based aggregate, and a preparation method and application thereof. Background Phosphoric acid is prepared by wet process by decomposing phosphorite (fluorapatite) with concentrated sulfuric acid at 75-80 deg.c to extract phosphoric acid, and in this process, an industrial by-product gypsum, phosphogypsum, is produced. The main component of phosphogypsum is CaSO 4·2H2 O, but unlike natural gypsum, the phosphogypsum also contains a large amount of impurities including phosphorus and fluorine compounds, residual organic mineral flotation agents, acid, heavy metal elements and the like. These impurities greatly affect phosphogypsum properties, making it difficult to recycle in large quantities. At present, the comprehensive effective utilization rate of phosphogypsum is lower than 40%, and the yield of phosphogypsum is 4-5 times of that of phosphoric acid, so how to effectively treat phosphogypsum becomes a difficult problem for limiting the healthy development of the phosphorus chemical industry. There have been some practices that the preparation of phosphogypsum-based Leng Nianjie aggregate based on "persulfate phosphogypsum slag cement" (hereinafter referred to as phosphogypsum-based aggregate) by using phosphogypsum is an effective way for large-scale digestion of phosphogypsum, for example, chinese patent document CN113354376A discloses a phosphogypsum-based aggregate for road engineering and a preparation method thereof, the aggregate is prepared by mixing 50-80% of phosphogypsum, 15-45% of waste slag powder and 3-6% of alkaline excitant into powder, spraying a solution of sodium hexametaphosphate, cellulose ether and water by a granulator to prepare raw spheres, immersing the raw spheres into water for curing, spraying organic silicon to obtain the required aggregate, and Chinese patent document CN110451864A discloses a phosphogypsum baking-free haydite lightweight aggregate and a preparation method thereof, wherein the aggregate is prepared by granulating and adding water at a rate of 1.25-1.5L/min while granulating by a granulating device, and then immersing and curing the raw spheres into water or spraying organic silicon to obtain the required aggregate after immersing and curing by 14-28d of the required powder, and drying and sieving the required aggregate. The existing phosphogypsum-based aggregate manufacturing process has the problems that the water for granulation is not controlled uniformly, and green balls are easy to bond with each other, so that the prepared phosphogypsum-based aggregate has uneven particle size and low strength, and the components contain excessive sulfate, so that the phosphogypsum-based aggregate is incompatible with silicate cement, and the like. Disclosure of Invention The invention aims to provide a full-solid waste phosphogypsum-based aggregate, and a preparation method and application thereof, which are used for solving the problems that the existing phosphogypsum-based aggregate manufacturing process has uneven control of water for granulation, and raw balls are easy to bond with each other, so that the prepared phosphogypsum-based aggregate has uneven particle size and low strength, and the components contain excessive sulfate, so that the phosphogypsum-based aggregate is incompatible with silicate cement, and the like. The invention provides a preparation method of a full solid waste phosphogypsum-based aggregate, which comprises the following steps of adding water into a granulating material to be pre-stirred to obtain a premix, granulating the premix to obtain water-drop green pellets, continuously adding the granulating material or a reconstruction material into the water-drop green pellets, reconstructing the water-drop green pellets, continuously granulating to obtain capillary green pellets, and curing the capillary green pellets to obtain the full solid waste phosphogypsum-based aggregate, wherein the granulating material comprises 70-85% of phosphogypsum, 10-25% of solid waste silicon-aluminum materials and 1-20% of solid waste alkali excitant, and the reconstruction material comprises 0-20% of phosphogypsum, 60-90% of solid waste silicon-aluminum materials and 1-20% of solid waste alkali excitant in percentage by mass. In the preparation method of the full-solid waste phosphogypsum-based aggregate, the inventor researches and discovers that the traditional sprinkling granulation refers to that particles are wetted in a form of spraying water mist in the granulation process, a layer of water film is formed on the surface, and a liquid bridge is formed among the particles due to the surface tension of water (0.072N/m at 25 ℃) to promote the aggregation growth of the particles, but the sprinkling