Sintering Coal Pond Ash for Lightweight Ceramic Sand

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Solution Overview

Problem

Current methods fail to effectively utilize coal pond ash due to its distinct characteristics, and there is a pressing need for a sustainable alternative to depleting natural sand resources in construction industries, as traditional processes are costly, energy-intensive, and environmentally detrimental.

Innovation Solution

A novel process involving direct granulation and sintering of a mixture of coal pond ash and fly ash, eliminating the need for drying and producing lightweight ceramic sand particulates, which are competitive with natural sand and crushed stones in terms of cost and environmental impact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If wet disposal system is used for coal combustion products, then large area of land and huge quantity of water are required, but this reduces the pozzolanic reactivity of fly ash and increases environmental impact

Engineering Contradiction:
Improvepozzolanic reactivityVSAvoidenvironmental impact
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The invention converts the harmful waste by-product (coal combustion products with reduced pozzolanic reactivity from wet disposal) into a beneficial building material (lightweight ceramic sand). The process transforms the degraded fly ash into a useful product that can substitute natural sand, thereby converting an environmental hazard into an economic and ecological benefit.

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

Solution Approach 2:

The invention changes the physical and chemical parameters of the coal combustion products through controlled heating and sintering processes. By adjusting temperature, heating rate, and holding time, the process transforms the material properties to achieve the desired bulk density (0.8-1.8 g/cm³) and pozzolanic reactivity, converting waste into a functional building material.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If natural sand is used for construction, then good quality sand is available, but natural sand resources are fast depleting and ecologically fragile

Engineering Contradiction:
Improvequality of sandVSAvoidavailability of natural sand
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The invention changes the parameters of synthetic lightweight ceramic sand to match or exceed natural sand properties. By controlling bulk density (0.8-1.8 g/cm³), particle size distribution, and shape during the sintering process, the synthetic sand achieves comparable quality to natural sand while being sustainably produced from abundant waste materials.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite material system using coal combustion products (fly ash and bottom ash) combined with binders and admixtures to produce lightweight ceramic sand. This composite approach leverages the pozzolanic properties of fly ash and the structural characteristics of bottom ash to create a material that replicates natural sand functionality.

Inventive Principle:
Principle #40Composite materials

3Ease of manufacture

If traditional methods are used to produce lightweight ceramic materials, then the process is energy-intensive and costly, but sustainable alternative is needed

Engineering Contradiction:
Improvemanufacturing cost and energy consumptionVSAvoidenergy consumption
Core Design Contradiction:
Ease of manufactureVSLoss of energy

Solution Approach 1:

The invention performs preliminary action by using pre-heating zones and optimizing the heating curve to reduce energy consumption. The process includes a drying phase followed by gradual heating, which prevents thermal shock and reduces the total energy required for sintering compared to traditional rapid-heating methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention optimizes manufacturing parameters including heating rate (5-10°C/min), holding time (1-4 hours), and sintering temperature (900-1200°C) to achieve the desired bulk density and strength while minimizing energy consumption. These parameter optimizations make the process economically viable and environmentally sustainable.

Inventive Principle:
Principle #35Parameter changes

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 process enables the economical production of lightweight ceramic sand at high throughput, reducing environmental impact and alleviating waste disposal issues while providing a sustainable alternative to natural sand and crushed stones, supporting ecological conservation and economic benefits.

Implementation Method 1

a novel process of manufacturing sintered synthetic lightweight ceramic sand particulates directly from coal pond ash

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentUS11384022B2Method of producing lightweight ceramic sand particulates from coal pond ash and use thereof
Publication Date: 2022.07.12 KHAN ABBAS

AI summary

The present invention relates to fabricating lightweight ceramic sand as a building and construction material. More specifically it relates to a novel process of manufacturing sintered synthetic lightweight ceramic sand particulates directly from pond ash and fly ash as a secondary raw material. The said synthetic lightweight ceramic sand can be used as a building material. The novel feature of the invention is to manufacture low cost lightweight sand at high throughput to compete against the fast depleting natural sand and crushed stones.