Recycled Mineral Aggregates Using Process Auxiliaries Against Agglomeration
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Solution Overview
Problem
Current methods for recycling demolition rubble and building waste to produce aggregates and pulverulent mineral materials are inefficient, leading to agglomeration issues, reduced throughput, and suboptimal material properties, especially when used in hydraulically setting compositions.
Innovation Solution
The use of process auxiliaries such as polycarboxylate ethers, glycols, organic amines, and lignosulfonates in a combined chemical-mechanical process to carbonate and mechanically remove hardened mineral binders from aggregates, optimizing particle size distribution and moisture content, and preventing agglomeration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current comminution methods are used to recycle demolition rubble, then coarse fractions can be reused, but finer fractions cause agglomeration and blockage of machines
Solution Approach 1:
The patent introduces process auxiliaries (chemical additives) as intermediaries between the comminution process and the aggregate particles. These auxiliaries adsorb onto particle surfaces, creating a protective barrier that prevents direct particle-to-particle contact and eliminates agglomeration and caking issues that currently block machine operation
Solution Approach 2:
The patent changes the surface properties of particles by introducing chemical process auxiliaries that modify surface charge, hydrophobicity, or steric characteristics. This parameter change transforms the particles from a state prone to agglomeration to a state of stable dispersion, enabling continuous high-throughput processing
2Manufacturing precision
If complete removal of hardened mineral binder is achieved, then aggregate quality improves, but energy input and processing time increase
Solution Approach 1:
The patent applies process auxiliaries before or during the early stages of comminution to weaken the bond between hardened mineral binder and aggregate particles. This preliminary chemical action reduces the mechanical energy required for complete binder removal, achieving high aggregate quality with lower overall energy input
Solution Approach 2:
The patent partially replaces mechanical comminution energy with chemical action from process auxiliaries. The chemicals facilitate binder breakdown and particle separation, reducing reliance on high-energy mechanical crushing while achieving complete binder removal and high aggregate quality
3Productivity
If finer fractions are discarded to avoid agglomeration, then machine blockage is prevented, but material reuse efficiency decreases
Solution Approach 1:
The process auxiliaries act as intermediaries that enable finer fractions to be processed and reused without causing agglomeration. By adsorbing onto fine particle surfaces, these chemicals prevent the harmful interactions that would otherwise lead to caking, allowing 100% material reuse while maintaining machine operation
Solution Approach 2:
The patent changes the physical-chemical parameters of finer fractions through process auxiliary addition, transforming them from a problematic waste stream into a usable resource. The modified particles maintain their fine size for high reuse value while exhibiting anti-agglomeration properties that enable full incorporation into recycled aggregate
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
This approach enhances the efficiency of the recycling process by reducing energy input, increasing throughput, and improving the properties of resulting materials for use in hydraulic compositions, including free flow, setting times, and strength.
Implementation Method 1
the process auxiliary may be a polycarboxylate ether... avoidance or considerable reduction of unwanted agglomeration of particles
Implementation Method 2
the process auxiliary may be a lignosulfonate... avoidance or considerable reduction of unwanted agglomeration of particles
Implementation Method 3
treating the starting material in a disintegration operation, especially under abrasive conditions, wherein the hardened mineral binder is at least partly, especially essentially completely, carbonated
Implementation Method 4
treating the starting material in a disintegration operation, especially under abrasive conditions, wherein the hardened mineral binder is at least partly... removed from the surface of the aggregates
Data Source
AI summary
Methods of obtaining aggregates and/or pulverulent mineral material from a starting material comprising hardened mineral binder and aggregates utilizing process auxiliaries selected from the group consisting of polycarboxylate ethers and/or esters (PCE), glycols, organic amines, especially alkanolamines, ammonium salts of organic amines with carboxylic acids, surfactants, especially nonionic surfactants, gemini surfactants, calcium stearate, alkoxylated phosphonic or phosphoric esters, propane-1,3-diol, carboxylic acids, sulfonated amino alcohols, boric acid, salts of boric acid, borax, salts of phosphoric acid, gluconate, iron sulfate, tin sulfate, antimony salts, alkali metal salts, alkaline earth metal salts, lignosulfonates, glycerol, melamine, melamine sulfonates, water absorbents in the form of a superabsorbent polymer or in the form of a sheet silicate, anticaking agents, sugars, sugar acids, sugar alcohols, phosphates, phosphonates, and mixtures thereof.