Porous Material from Steel Slag Sintering
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Solution Overview
Problem
The global steel industry generates large amounts of basic-oxygen-furnace slag and electric arc furnace slag, which contain free calcium oxide and magnesium oxide. These materials are difficult to stabilize and reuse due to volume expansion when exposed to water, and conventional treatment methods are time-consuming, laborious, and costly.
Innovation Solution
A porous and lightweight material is created by mixing reducing slag, waste flame retardant material, and waste glass with an alkaline activator and a foaming agent. The mixture is molded, dried, and then sintered at temperatures between 600°C to 800°C to produce a honeycomb structured material with specific chemical composition and properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional curing agent method is used to treat reducing slag and waste flame retardant material, then the volume expansion problem is addressed, but the treatment process becomes time-consuming, laborious, and costly
Solution Approach 1:
The invention changes the chemical parameters of the waste materials by controlling the sintering temperature (600-800°C) and duration (1-4 hours) to transform free calcium oxide and magnesium oxide into stable compounds, eliminating volume expansion issues without requiring time-consuming curing agents
Solution Approach 2:
The invention replaces the mechanical mixing and chemical curing process with a thermal sintering process, substituting a simple heating operation for the complex multi-step conventional treatment that involves adding curing agents and extended curing time
2Productivity
If reducing slag and waste flame retardant material are reused directly, then resource utilization is improved, but the quality stability becomes difficult to maintain due to volume expansion
Solution Approach 1:
The invention performs preliminary sintering treatment on the reducing slag and waste flame retardant material before reuse, pre-stabilizing the chemical composition and eliminating potential volume expansion issues before the materials are incorporated into final construction products
Solution Approach 2:
The invention creates a composite porous material by combining reducing slag, waste flame retardant material, and waste glass in specific proportions (40-45% each), where the sintering process integrates these components into a stable composite structure with improved quality consistency
3Reliability
If sintering temperature is increased to improve material stability, then quality stability improves, but energy consumption increases
Solution Approach 1:
The invention optimizes the sintering parameters by setting the temperature range at 600-800°C and duration at 1-4 hours, which is sufficient to stabilize the chemical composition and eliminate volume expansion problems without excessive energy consumption
Solution Approach 2:
The invention uses waste glass as a fluxing agent that lowers the sintering temperature requirement, allowing the reducing slag and waste flame retardant material to be stabilized at lower temperatures (600-800°C) rather than requiring higher temperatures that would consume more energy
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 resulting porous material has a compressive strength of 200 kgf/cm² to 400 kgf/cm², a density of 1.5 g/cm³ to 1.65 g/cm³, and water absorption of 5% to 20%. It also exhibits thermal conductivity of 0.4 W/m·K to 0.8 W/m·K, flame resistance, and thermal insulation up to 1000°C to 1200°C, making it suitable for construction applications and addressing the treatment issues of the reducing slag and waste materials.
Implementation Method 1
sintering the green body to form the porous material, wherein the sintering step is performed at a temperature of 600°C to 800°C for a period of 1 hour to 4 hours
Implementation Method 2
mixing raw materials, an alkaline activator and a foaming agent to form a mixture
Data Source
AI summary
A porous structure includes 3 wt% to 4.2 wt% of Mg, 14 wt % to 18 wt% of Ca, 12 wt% to 15 wt% of Si, 0.8 wt% to 1.5 wt% of Al, 0.1 wt% to 0.3 wt% of K, 0.4 wt% to 2 wt% of Fe, 7 wt% to 8.5 wt% of Na, 4.8 wt% to 7.6 wt% of B, and 48 wt% to 52 wt% of O.