Dross Pellets with Internal Channels for Roasting
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Solution Overview
Problem
Current dross treatment technologies in aluminum recycling are inefficient and hazardous, requiring high energy and water usage, generating toxic gases, and posing challenges in handling and disposal due to the production of black dross and white dross byproducts.
Innovation Solution
A method involving the disintegration of dross into pellets with internal channels, where additives oxidize or decompose at specific temperatures to expose channels, allowing gas passage and facilitating thermal processing, thereby improving salt extraction efficiency and reducing hazardous byproduct handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dross is treated using current high-temperature heating and leaching technologies, then metal recovery is achieved, but energy consumption and water usage increase significantly
Solution Approach 1:
The dross is pre-treated by drying and granulating before thermal processing. This preliminary preparation creates a uniform, porous structure that enhances heat penetration and reduces the energy required during subsequent high-temperature treatment, while also improving metal recovery efficiency
Solution Approach 2:
The granulated dross forms a porous structure that increases surface area and improves heat transfer efficiency during thermal processing. This porous morphology allows better penetration of heating media and facilitates faster, more energy-efficient metal recovery
2Reliability
If dross is treated using conventional leaching and evaporation processes, then salt is recovered, but substantial amounts of water and energy are consumed
Solution Approach 1:
The process changes the physical parameters of dross through drying and granulation, creating a structure that facilitates more efficient salt extraction with reduced water consumption. The granulated form improves leaching efficiency, allowing salt recovery with minimal water input
3Ease of manufacture
If dross is handled and transported to separate treatment facilities, then processing can occur, but handling complexity and transportation requirements increase
Solution Approach 1:
The treatment process is segmented into distinct stages: drying, granulation, and thermal processing. Each stage produces a more manageable material form, reducing handling complexity and eliminating the need for separate specialized facilities for each processing step
4Productivity
If dross is subjected to high-temperature thermal processing, then metal oxidation and salt evaporation occur, but reaction vessel wear increases
Solution Approach 1:
By pre-drying and granulating the dross, the material achieves optimal moisture content and uniform structure before entering the high-temperature reaction vessel. This preparation reduces abrupt thermal shocks and promotes more uniform heating, thereby reducing stress on the vessel lining and extending its service life
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 approach enhances the efficiency and speed of salt extraction, oxidizes residual carbon and metals, and allows for high-temperature processing without additional heat sources, reducing the volume of hazardous byproducts and extending reaction vessel life.
Implementation Method 1
an additive selected to oxidize or decompose at a channel exposure temperature at or below 800° C.
Implementation Method 2
an additive selected to oxidize or decompose at a channel exposure temperature at or below 800° C.
Implementation Method 3
heating the dross pellets to a temperature at or above the channel exposure temperature
Implementation Method 4
The channels of a pellet may permit gas to enter and pass through the pellet
Data Source
AI summary
The efficiency of roasting black dross can be improved by pre-processing the black dross before roasting. Black dross can be crushed and reconstituted into pellets having internal channels. The internal channels can be filled with additives designed to fully oxidize during a dross roasting process, enabling the internal channels to be open and gas to flow therethrough during a dross roasting process. The crushed black dross can be crushed to pieces below 10 mm and screened for larger pieces prior to pelletizing to ensure consistent pellets. Optionally, an eddy current separator can remove some metallic aluminum from the crushed black dross prior to pelletizing.