Caprolactam Grinding Additive for Cement Strength

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Solution Overview

Problem

Current grinding additives for cement production, such as triisopropanolamine, improve late strength but have limited effect on early strength and often increase air entrainment, leading to high porosity and poor surface finishes in cement compositions.

Innovation Solution

A grinding additive comprising 6% to 80% caprolactam and 1.5% to 30% aminocaproic acid, used before or during grinding, which reduces agglomeration and energy consumption, and enhances both early and late strength properties without significant air entrainment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If known grinding additives like triisopropanolamine are used to improve late strength, then 28-day strength is improved, but early strength remains limited and air entrainment increases

Engineering Contradiction:
Improve28-day strengthVSAvoidair entrainment
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The invention changes the chemical parameters of the grinding additive by using caprolactam (a cyclic amide) instead of traditional amine-based additives like triisopropanolamine. This parameter change in the additive's molecular structure fundamentally alters its interaction with cement particles, providing strength enhancement without the harmful air-entraining effect characteristic of conventional additives.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention employs a simple, cost-effective grinding additive (caprolactam) that performs multiple functions effectively. Caprolactam is a well-known industrial chemical with established safety and handling characteristics, making it a practical replacement for more complex amine-based additives that require careful management of their side effects.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If grinding additives are used to achieve maximum fineness of grind, then specific surface area is improved, but energy consumption increases

Engineering Contradiction:
Improvefineness of grindVSAvoidenergy consumption
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The caprolactam additive exhibits self-service properties by automatically adsorbing onto particle surfaces during the grinding process itself, without requiring separate application steps. The additive's molecular structure enables it to spontaneously interact with and coat the grinding particles, providing continuous protection against agglomeration and reducing the energy needed to maintain fine particle sizes throughout the grinding operation.

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If grinding additives prevent agglomeration, then homogeneity is improved, but the additive cost increases

Engineering Contradiction:
ImprovehomogeneityVSAvoidadditive cost
Core Design Contradiction:
Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The invention utilizes caprolactam, a commercially abundant and inexpensive chemical substance, as the grinding additive. This choice of additive provides effective agglomeration prevention and homogeneity improvement at a lower cost compared to specialized amine-based additives, making the process economically viable for large-scale cement production while maintaining composition stability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 additive significantly reduces agglomeration, lowers energy expenditure, and improves strength at all stages of cement curing, resulting in low porosity and better surface finishes.

Implementation Method 1

Grinding additives act by enveloping the particles that have a tendency towards agglomeration with thin layers, more particularly monomolecular layers, and thus lead to neutralization of the surface charges

Methodology Applied
Scientific EffectSurface charge neutralization: Adsorption

Implementation Method 2

In addition, grinding additives are absorbed on the fracture surfaces of the grains prior to separation, and prevent them from reuniting

Methodology Applied
Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentEP2844622B1Grinding additive for mineral binders
Publication Date: 2016.11.09 CONSTRUCTION RESEARCH & TECHNOLOGY GMBH

AI summary

The invention relates to a method for grinding an inorganic solid from the series cement clinker, pozzolan and/or raw material for cement production, where a grinding additive is added before or during grinding, and the grinding additive, based on the dry mass, comprises 6% to 80% by weight of caprolactam and 1.5% to 30% by weight of aminocaproic acid, where, based in each case on the dry mass, 0.002% to 2% by weight of the grinding additive is used, based on the total solid. Further claimed are a grinding additive and the use thereof for increasing the compressive strength of the cured product produced therewith.