Non-sintered Lightweight Aggregate from Solid Wastes
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Solution Overview
Problem
Current methods for producing lightweight aggregates from sulfur-based and alkaline-based solid wastes face issues such as high energy consumption, high CO2 emission, low utilization rate of solid wastes, complex processes, and poor product controllability due to the need for sintering and secondary granulation, as well as the use of high-energy silicate cement.
Innovation Solution
A non-sintered high-strength lightweight aggregate is prepared by stirring, granulation, and foaming using sulfur-based and alkaline-based solid wastes, along with a ferro-aluminum-sulfur cementing material and a foaming agent, which eliminates the need for high-temperature sintering and secondary granulation, and utilizes a simple and efficient process to create a high-value product with improved strength and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional sintering methods are used to prepare lightweight aggregates, then high strength can be achieved, but energy consumption increases and CO2 emissions increase
Solution Approach 1:
The patent changes the fundamental parameter of preparation method from high-temperature sintering to low-temperature chemical reaction. By using alkaline waste residues to activate cementing materials at room temperature or low temperature, the process achieves strength development without the high energy input of sintering, directly resolving the contradiction between strength and energy consumption
Solution Approach 2:
The patent replaces the thermal-mechanical sintering process with a chemical-wet process. Instead of using high temperature and pressure to bind particles, the invention uses chemical reactions between alkaline waste residues and cementing materials to form binding compounds, substituting a high-energy physical process with a low-energy chemical process
2Productivity
If sintering of solid wastes is used to prepare lightweight aggregates, then production can proceed, but homogenization of solid wastes deteriorates and product stability worsens
Solution Approach 1:
The patent applies preliminary action by pre-mixing and pre-reacting the solid wastes with cementing materials and water before granulation. This pre-treatment ensures homogeneous distribution of components and initiates chemical reactions that stabilize the composition, preventing fluctuations during the sintering or drying process and improving product stability
Solution Approach 2:
The patent introduces water and chemical admixtures as intermediaries that facilitate homogeneous mixing and chemical reaction among the solid waste components. These intermediaries promote uniform distribution of alkaline residues and cementing materials, ensuring consistent composition throughout the product and improving stability
3Shape
If secondary granulation using roller and disc granulator is used, then granulation can be achieved, but process complexity increases
Solution Approach 1:
The patent merges the mixing, granulation, and forming operations into a single integrated process step. By combining these operations that were previously separate (mixing followed by secondary granulation), the invention simplifies the process equipment and reduces operational complexity while still achieving the required aggregate shape and structure
Solution Approach 2:
The patent segments the granulation process into a single-step direct granulation operation rather than requiring sequential secondary granulation. This segmentation eliminates the need for complex multi-stage equipment like roller and disc granulators, reducing device complexity while maintaining product quality
4Strength
If ordinary silicate cement is used as binding material, then strength can be developed, but CO2 emission increases and energy consumption increases
Solution Approach 1:
The patent discards ordinary silicate cement and recovers/utilizes alkaline waste residues (such as fly ash, slag, or other industrial by-products) as the primary binding material. This substitution eliminates the high CO2 emissions associated with cement production while maintaining binding strength through the chemical reactivity of the alkaline residues with available silica and alumina sources in the mixture
Solution Approach 2:
The patent converts harmful waste materials (alkaline waste residues that would otherwise be discarded) into beneficial binding materials. By utilizing the chemical reactivity of these waste products to form binding compounds, the invention transforms an environmental hazard into a strength-providing component, simultaneously reducing CO2 emissions and improving product performance
5Strength
If multiple additives are added to improve strength, then lightweight aggregate strength increases, but production cost increases
Solution Approach 1:
The patent applies multi-functionality by using alkaline waste residues that simultaneously serve as both the binding material and the strength-enhancing additive. This single material performs multiple functions: providing binding capability, contributing to strength development, and replacing the need for separate chemical additives, thereby reducing production cost while maintaining or improving strength
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 method achieves a lightweight aggregate with high mechanical strength, low bulk density, and improved environmental sustainability by effectively utilizing solid wastes, reducing production costs, and enhancing product performance, making it suitable for various construction applications.
Implementation Method 1
foaming agent, which eliminates the need for high-temperature sintering and secondary granulation
Implementation Method 2
stirring, granulation, and foaming using sulfur-based and alkaline-based solid wastes
Implementation Method 3
stirring, granulation, and foaming using sulfur-based and alkaline-based solid wastes
Data Source
AI summary
A non-sintered high-strength lightweight aggregate one-shot prepared from sulfur-based and alkaline-based solid wastes by stirring, granulation, and foaming, and a preparation method therefor and use thereof. The non-sintered high-strength lightweight aggregate is prepared from a sulfur-based solid waste, an alkaline-based solid waste, an auxiliary cementing material, a ferro-aluminum-sulfur cementing material, water, and a foaming agent as raw materials. Based on the mass of the total solid, the total content of the sulfur-based solid waste, the alkaline-based solid waste, and the auxiliary cementing material is 80-90 wt %, and the content of the ferro-aluminum-sulfur cementing material is 10-20 wt %. The mass ratio of the water to the total solid is (15-20):(80-85). The foaming agent accounts for 0.3-0.7% of the mass of the total solid. The mass ratio between the sulfur-based solid waste, the alkaline-based solid waste, and the auxiliary cementing material is (27-33):(27-33):(18-25).