Coated Casting Sand Composition for Longer Usable Time

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Solution Overview

Problem

Existing casting sands produced using inorganic binding agents on regenerated sand face issues with insufficient liquid crosslinking, leading to inadequate usable time and increased environmental load due to high-temperature treatments.

Innovation Solution

A casting sand with a first coating layer on regenerated or refractory aggregates, containing SiO2, and a second coating layer of silicate, controlling the cation exchange capacity (CEC) between 3 mmol (+)/kg and 40 mmol (+)/kg, to enhance storage stability and reduce energy consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If high-temperature treatment (600°C to 800°C) is applied to regenerated sand, then the usable time of casting sand is extended, but energy consumption and CO2 emission increase significantly

Engineering Contradiction:

Improveusable time of casting sandVSAvoidenergy consumption

Core Design Contradiction:

Duration of action of moving objectVSUse of energy by moving object

Solution Approach 1:

The invention changes the temperature parameter from high-temperature treatment (600-800°C) to low-temperature treatment (100-400°C), and introduces a new parameter (CEC value between 3-40 mmol(+)/kg) to control the chemical properties of the coating layer, thereby extending usable time while reducing energy consumption

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite structure with a coating layer on the aggregate surface, where the coating layer contains specific compounds (such as water glass, alumina, silica) that provide both the desired usable time extension and low CEC value, achieving the dual goal of performance improvement and energy reduction

Inventive Principle:

Principle #40Composite materials

2Duration of action of moving object

If high-temperature treatment (600°C to 800°C) is applied to regenerated sand, then the usable time of casting sand is extended, but CO2 emission increases

Engineering Contradiction:

Improveusable time of casting sandVSAvoidCO2 emission

Core Design Contradiction:

Duration of action of moving objectVSObject-generated harmful factors

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention converts the harmful high-temperature treatment process into a beneficial low-temperature process by using chemically active coating materials that achieve the same usable time extension effect at lower temperatures, thereby turning the harmful CO2 emission into a benefit of reduced environmental impact

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of manufacture

If inorganic binding agent is applied to regenerated sand, then casting sand can be produced, but liquid crosslinking is insufficient and usable time is limited

Engineering Contradiction:

Improvecasting sand productionVSAvoidusable time

Core Design Contradiction:

Ease of manufactureVSDuration of action of moving object

Solution Approach 1:

The invention changes the chemical composition parameters of the coating layer to achieve a CEC value between 3-40 mmol(+)/kg, and adjusts the water glass modulus and content parameters to optimize liquid crosslinking, thereby extending usable time while maintaining ease of manufacture

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite coating layer combining water glass (providing liquid crosslinking) with alumina and silica (controlling CEC value), where the synergistic interaction between these materials achieves both sufficient liquid crosslinking and extended usable time

Inventive Principle:

Principle #40Composite materials

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 solution improves storage stability and reduces environmental impact by maintaining usable time while minimizing thermal energy consumption and CO2 emissions.

Implementation Method 1

it is effective to use a casting sand in which a coating layer is applied to a regenerated sand or a refractory aggregate containing SiO2 in a casting sand for a mold using casting sand to control a cation exchange capacity (CEC) to a specific value

Methodology Applied

Scientific EffectCation exchange capacity (CEC): Ion Exchange

Implementation Method 2

casting may not be performed appropriately due to insufficient liquid crosslinking by heating

Methodology Applied

Scientific EffectLiquid crosslinking: Chemical Bonding

Data Source

PatentEP4711056A1Casting sand for casting mould and method for producing same, casting mould, and method for improving storage stability of casting sand for casting mould

Publication Date: 2026.03.18 KAO CORP

AI summary

A casting sand for a mold includes a casting sand in which a first coating layer is disposed on a surface of one or two kinds of aggregates selected from a regenerated sand (A) and a refractory aggregate (B); and a second coating layer containing a silicate on the first coating layer of the casting sand, in which a cation exchange capacity (CEC) of the casting sand is 3 mmol (+)/kg or more and 40 mmol (+)/kg or less.