Demetallized Steel Slag Granules With Controlled Iron and Particle Size
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Solution Overview
Problem
The demand for high-quality blast media has increased, with coal slag unable to meet market needs due to declining coal burning and limited availability of copper slag, and existing roofing granules are heavy and have inconsistent particle sizes, making them costly and less effective.
Innovation Solution
Demetallizing and processing steel furnace slag to produce a granular material with low iron content and consistent particle sizes, suitable for use as abrasive blast media and roofing granules, which can be crushed and screened to specific sizes for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If coal slag is used as abrasive blasting media, then cleaning performance is high, but availability decreases due to reduced coal burning
Solution Approach 1:
The patent changes the source material parameter from coal slag to steel furnace slag, and modifies the material composition by demetallizing the slag to reduce iron content. This transforms the material properties to match the performance characteristics of coal slag while utilizing an alternative source that is more available in the market.
Solution Approach 2:
The patent processes steel furnace slag, which is a byproduct of steelmaking, into a usable abrasive material. This utilizes an otherwise wasted material from the steel industry, converting it into a functional substitute for coal slag that can be reliably sourced and maintained in supply.
2Adaptability or versatility
If copper slag is used as abrasive blasting media, then alternative to coal slag is provided, but availability is limited in the United States
Solution Approach 1:
The patent creates a universal solution by processing steel furnace slag into demetallized granules that can serve as an abrasive blasting media alternative. The material is adapted to perform the same function as both coal slag and copper slag, providing a single versatile alternative that overcomes the availability limitations of the other options.
Solution Approach 2:
The patent changes the material source from copper slag to steel furnace slag, and modifies its composition through demetallization. This parameter change enables the material to fulfill the role of an alternative blast media while being more widely available in the United States market.
3Ease of manufacture
If quarried rock is used as roofing granule, then most common material is used, but particle size is inconsistent and weight is high
Solution Approach 1:
The patent segments the steel furnace slag into controlled particle sizes through systematic crushing and screening processes. This segmentation creates uniform granules with consistent dimensions, transforming the material from an uncontrolled byproduct into a precision roofing granule that matches or exceeds the quality of quarried rock.
Solution Approach 2:
The patent changes the physical state and composition parameters of steel furnace slag through demetallization and controlled crushing. This transforms the material into a fine, uniform granule with consistent particle size and reduced weight, overcoming the limitations of traditional quarried rock while maintaining ease of manufacture.
4Reliability
If demetallization process is applied to steel furnace slag, then iron content is reduced, but processing complexity increases
Solution Approach 1:
The patent extracts and removes metallic iron from steel furnace slag through magnetic separation processes. This extraction step isolates the non-metallic slag components, creating demetallized granules with controlled iron content. The systematic removal process, while adding processing steps, ensures reliable control over the final material composition.
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 demetallized slag particles provide a high-quality, cost-effective blast media with improved cleaning rates and reduced granule breakdown, and as roofing granules, they offer a consistent surface profile and better compatibility with asphalt, enhancing both blasting and roofing applications.
Implementation Method 1
The slag can be demetallized (e.g., using a magnet) such that an iron-compound content (e.g., content of metallic iron and/or of one or more iron oxides) of the demetallized slag
Data Source
AI summary
Some methods for making a granular material comprise crushing demetallized slag particles with one or more crushers and screening the crushed demetallized slag particles with one or more screens to separate the demetallized slag particles into two or more fractions, the granular material comprising at least one of the fractions of the demetallized slag particles. Prior to the crushing, ones of the demetallized slag particles having a size that is less than or equal to 2 inches can account for at least 90% of the demetallized slag particles. An iron-compound content of the demetallized slag particles, by weight, can be less than or equal to 10%. Crushing and screening can be performed such that ones of the demetallized slag particles of the granular material having a size that is less than or equal to 1.25 mm account for at least 90% of the demetallized slag particles of the granular material.