Filter Powder Pyrolysis for Aluminium Slag Recycling
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Solution Overview
Problem
Current methods for recycling filter powders from gas cleaning filters in aluminium refineries are inefficient, leading to production delays and environmental issues due to the handling and treatment challenges posed by their composition and reactivity, resulting in zero recycling and potential contamination of the end product.
Innovation Solution
A recycling system integrated into the saline slag treatment process, involving mechanical grinding, dissolution, reaction, crystallization, pyrolysis, and gas treatment steps to break down organic and toxic substances, allowing for the safe incorporation of filter powders into the saline slag recycling process, achieving zero dumping and improving production efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If filter powders are dumped in authorized dump sites, then environmental compliance is maintained, but zero recycling goal is not achieved and resource loss occurs
Solution Approach 1:
The patent converts the harmful organic matter and toxic substances in filter powders into beneficial outcomes by using controlled pyrolysis to destroy these contaminants and generate energy, while the resulting carbon-rich solid residue becomes a valuable resource for incorporation into saline slag recycling, achieving both zero dumping and resource recovery
Solution Approach 2:
The patent applies parameter changes by controlling the pyrolysis temperature (500-600°C) and atmosphere to selectively decompose organic matter and toxic substances while preserving the valuable carbon content and metal particles, transforming the filter powder from a hazardous waste into a processable material
2Productivity
If filter powders are mixed with saline slag in the furnace, then recycling process is simplified, but production time increases and cost-effectiveness decreases
Solution Approach 1:
The patent performs preliminary action by pre-treating filter powders through pyrolysis before they enter the saline slag recycling process. This preliminary destruction of organic matter and toxic substances prevents interference with the subsequent melting and dissolution steps, maintaining production speed while enabling effective recycling
3Object-affected harmful factors
If filter powders undergo wet treatment process, then toxic substances are not destroyed but incorporated into end product, reducing product quality
Solution Approach 1:
The patent converts the harmful organic matter and toxic substances into beneficial outcomes by using controlled pyrolysis to destroy these contaminants and generate energy, while the resulting carbon-rich solid residue becomes a valuable resource for incorporation into saline slag recycling
Solution Approach 2:
The patent replaces the wet treatment process with a thermal treatment process (pyrolysis). Instead of using water and chemical reactions to handle toxic substances, the system uses controlled thermal decomposition to destroy organics and volatilize toxins, achieving both detoxification and resource recovery
4Ease of operation
If filter powders are processed continuously from bag to hopper to feeder to auger, then handling efficiency is improved, but production delays occur due to reaction differences
Solution Approach 1:
The patent performs preliminary action by pre-treating filter powders through pyrolysis before they enter the continuous processing line with saline slag. This preliminary treatment ensures that filter powders are chemically prepared in advance, preventing reaction conflicts during continuous processing and maintaining both operational ease and production speed
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 system effectively recycles filter powders by destroying toxic substances and reducing waste, integrating them into the saline slag process, thereby enhancing the recycling efficiency and environmental sustainability of aluminium refineries.
Implementation Method 1
The filter powders, which are very lightweight and carbonaceous, must enter a rotating auger where they will be heated to a temperature of not less than 500°C and not more than 600°C. The organic and toxic substances breakdown in this heating
Implementation Method 2
part of the carbon and other combustibles burn in the controlled presence of air
Implementation Method 3
A series of powder entrainment gases are produced as a result of the operation. This powder must be retained and the gases neutralized and treated to thus be emitted to the atmosphere without creating environmental problems
Data Source
Figure 1
AI summary
The present invention relates to a process of treating filter powders (3) of the type produced in aluminium recycling processes in a recycling system for recycling the metal (1) of saline slag recycling (2), comprising at least a pyrolysis step (31) in which the filter powders (30) enter a rotating auger where they are heated to a temperature of not less than 500°C and not more than 600°C; and in which the organic and toxic substances breakdown in this heating and part of the carbon and other combustibles burn in the controlled presence of air, this air being mixed with the powder by the movement of the rotating auger; in which organic materials are oxidized due to the oxygen provided; and in which the solid result of the pyrolysis step (31) is added to the general saline slag recycling process (2).