High-Pressure Grinding Rolls for Selective Concrete Recycling

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Solution Overview

Problem

Conventional methods for processing concrete demolition material into particle size fractions are inefficient, fail to differentiate between components, leading to unnecessary crushing of valuable aggregates, inconsistent particle sizes, and increased energy consumption.

Innovation Solution

A method using a high-pressure grinding roll with a fixed and floating roll configuration, controlled by a hydraulic cylinder system, to achieve selective attrition grinding, ensuring consistent particle size reduction while preserving the integrity of larger particles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional crushers, ball mills, and hammer mills are used to separate concrete demolition material into multiple particle size fractions, then particles can be segregated to some extent, but valuable components such as gravel undergo undue crushing, reducing their usability and increasing energy consumption

Engineering Contradiction:
Improveparticle size consistencyVSAvoidvaluable aggregate loss
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The invention changes the fundamental parameter of the crushing mechanism from impact-based (conventional crushers, hammer mills) to friction-based (intermediate pressure grinding rolls). This parameter change allows for controlled size reduction that preserves valuable aggregate components while achieving consistent particle size fractions, directly resolving the contradiction between manufacturing precision and substance loss

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the conventional mechanical crushing system (crushers, ball mills, hammer mills) with an intermediate pressure grinding roll system that operates on friction principles. This substitution eliminates the need for high-impact mechanical forces that cause undue crushing of valuable components, thereby reducing both aggregate loss and energy consumption while maintaining particle size consistency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If conventional crushing methods are used, then material can be processed, but the particle sizes are inconsistent, requiring further processing steps that increase costs and resource consumption

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidparticle size uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention changes the processing parameter from high-impact crushing to intermediate pressure friction-based grinding, which inherently produces more uniform particle sizes. This parameter change eliminates the need for additional processing steps to achieve size uniformity, thereby improving productivity without sacrificing manufacturing precision

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If conventional crushing systems are used, then particles can be separated, but energy consumption increases due to unnecessary processing of valuable components

Engineering Contradiction:
Improveparticle size segregationVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The invention replaces energy-intensive conventional crushing systems with a friction-based intermediate pressure grinding roll system. This substitution reduces energy consumption significantly because the friction-based mechanism can achieve particle size segregation without the high-impact forces required by conventional systems, thereby resolving the contradiction between manufacturing precision and energy consumption

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 produces precise and consistent particle size fractions, enhancing the reusability of demolition waste, reducing energy consumption, and enabling the use of recycled aggregates in new concrete compositions without strength loss.

Implementation Method 1

one roll is a fixed roll fixed in a frame and the other roll is a floating or mobile roll positioned at a variable distance from the fixed roll by means of a hydraulic cylinder system

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

crushing the particles by means of a high-pressure grinding roll comprising a pair of counter-rotating rolls

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

pure attrition grinding ensures that the particle size reduction is achieved through surface abrasion

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4520434B1Method of processing concrete demolition material into a plurality of particle size fractions
Publication Date: 2026.05.13 HOLCIM TECHNOLOGY LTD
  • EP4520434B1 patent drawingFigure 1

AI summary

a method of processing concrete demolition material (2) into a plurality of particle size fractions, comprising: - providing particles of concrete demolition material (2), - crushing the particles by means of a high-pressure grinding roll (1) comprising a pair of counter-rotating rolls mounted in a frame, wherein one roll is a fixed roll (3) fixed in a frame and the other roll is a floating roll (4) positioned at a variable distance from the fixed roll (3) by means of a hydraulic cylinder system (7), thereby obtaining a crushed material (10), - screening the crushed material (10) in order to obtain at least two, in particular at least three, particle size fractions (12,13,14).