Hydraulic Phosphogypsum Cementitious Material High Dosage
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Solution Overview
Problem
The existing methods for preparing hydraulic phosphogypsum (PG) slag-based cementitious materials are limited in their ability to increase the dosage of PG beyond 50% without compromising the strength and physical properties of the material, as higher dosages result in incomplete wrapping of PG particles by hydration products.
Innovation Solution
A hydraulic PG-based cementitious material is developed using modified PG particles with a dosage of 50 wt% to 95 wt%, achieved through modification with a calcareous material and an auxiliary active powder, which allows for a high-strength, water-resistant material formation through gap grading particle accumulation and controlled chemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the dosage of PG is increased beyond 50% in excess-sulfate PG slag-based cementitious materials, then the utilization of PG waste material is improved, but the strength and physical properties of the material deteriorate due to incomplete wrapping of PG particles by hydration products
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific ratios of CaO (3-6%), MgO (2-5%), and Al2O3 (2-5%) in the phosphogypsum, and controls the particle size distribution (D10, D50, D90 values) to optimize the material properties. These parameter changes enable higher PG dosage while maintaining strength through improved hydration product formation and particle packing.
Solution Approach 2:
The patent creates a composite cementitious material system combining phosphogypsum with supplementary cementitious materials (slag, fly ash, mineral powder) in specific proportions. This composite approach allows the different materials to work synergistically, where the hydration products from multiple sources collectively wrap and bind the PG particles effectively, maintaining strength at high PG dosages.
2Quantity of substance
If the dosage of PG is increased to improve waste utilization, then the environmental benefit is improved, but the completeness of hydration product wrapping around PG particles deteriorates
Solution Approach 1:
The patent optimizes chemical parameters (CaO, MgO, Al2O3 content) and physical parameters (particle size distribution) of the phosphogypsum to ensure that even at 60-80% dosage, the hydration products can adequately wrap the PG particles. The controlled composition promotes more uniform and complete hydration product formation around each particle.
Solution Approach 2:
The patent uses supplementary cementitious materials (slag, fly ash, mineral powder) as intermediaries that facilitate the wrapping process. These materials generate additional hydration products that act as binding agents, ensuring complete coverage of PG particles even when PG dosage is high, thus maintaining structural integrity and reliability.
3Ease of manufacture
If traditional methods are used to prepare PG-based cementitious materials, then the production process is simple, but the maximum dosage of PG is limited to 50%
Solution Approach 1:
The patent modifies the chemical composition parameters of the phosphogypsum (adding controlled amounts of CaO, MgO, Al2O3) and adjusts particle size distribution parameters. These parameter changes enable the material to achieve higher PG dosage (60-80%) while maintaining adequate hydration product formation, breaking the 50% dosage limit of traditional methods without significantly complicating the production process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables a significant increase in PG dosage while maintaining high strength and water resistance, expanding the application scope of PG in various construction materials without relying on mineral powders, thus addressing the environmental and economic challenges associated with PG accumulation.
Implementation Method 1
the modified PG particles have a dosage up to 95 wt %, and can form a hydraulic structure after hydration
Data Source
AI summary
The present disclosure provides a hydraulic phosphogypsum (PG)-based cementitious material, and a preparation method and use thereof, belonging to the technical field of cementitious materials. The present disclosure provides a hydraulic PG-based cementitious material, including the following raw materials: modified PG particles and an auxiliary active powder, where the modified PG particles have a dosage of 50 wt % to 95 wt %; the modified PG particles are obtained by conducting modification on original PG particles through a calcareous material, and the calcareous material has a mass 3% to 5% of that of the original PG particles; and the original PG particles have typical dimensions of: a length of 50 μm to 200 μm and an aspect ratio of 1.5 to 5; and at least 80% of materials in the auxiliary active powder have a particle size of less than or equal to 60 μm. In the present disclosure, the hydraulic PG-based cementitious material adopts a particle accumulation method of gap grading. The modified PG particles have a dosage up to 95 wt %, and can form a hydraulic structure after hydration. Therefore, the cementitious material can be applied in various occasions.