Red Mud Dealkalization via SO2 Aeration and Leachate Reflux
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Solution Overview
Problem
Current methods for dealkalizing red mud are energy-intensive and costly, limiting their industrialization and comprehensive utilization, while also failing to effectively utilize the metal resources and treat sulfur-containing flue gas emissions.
Innovation Solution
A method involving grinding red mud, dissolving it in a slurry liquid with alkaline leachate, introducing SO2 and O2 for aeration oxidation, and adjusting pH levels to separate and recover aluminum and iron, utilizing SO2 to acidify and desulfurize the mixture, and refluxing alkaline leachate to enhance dealkalization, resulting in a process that reduces alkalinity and metal impurities in red mud.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional dealkalization methods are used, then red mud can be dealkalized, but energy consumption is high and treatment costs are high
Solution Approach 1:
The patent converts harmful SO2 waste gas into a useful reagent for dealkalizing red mud. The SO2 gas reacts with the alkaline components in red mud to remove sodium and potassium, transforming an environmental pollutant into a valuable processing agent that achieves both waste gas treatment and red mud dealkalization simultaneously.
Solution Approach 2:
The patent creates a multi-functional process where SO2 waste gas serves multiple purposes: it acts as a dealkalizing agent for red mud, serves as a sulfur source for producing aluminum sulfate, and simultaneously treats sulfur-containing waste gas emissions. This multi-functionality eliminates the need for separate dealkalization and waste gas treatment processes, reducing overall energy consumption.
2Manufacturing precision
If conventional dealkalization methods are used, then red mud can be dealkalized, but treatment costs are high and industrialization is difficult
Solution Approach 1:
The patent employs a self-service mechanism where the harmful SO2 waste gas from industrial processes automatically serves as the dealkalizing reagent. This eliminates the need to purchase and apply external chemical reagents, significantly reducing treatment costs and simplifying the industrialization process. The system uses its own waste output as the input needed for treatment.
Solution Approach 2:
By converting the harmful SO2 waste gas into a beneficial dealkalizing agent, the patent transforms an environmental liability into an economic asset. This approach eliminates waste gas treatment costs and dealkalization reagent costs simultaneously, making industrial implementation economically viable.
3Quantity of substance
If red mud is stockpiled, then it can be stored, but it occupies farmland and causes environmental pollution
Solution Approach 1:
The patent converts the harmful alkaline properties of red mud, which cause environmental pollution, into a useful chemical characteristic. The high alkalinity that makes red mud polluting also makes it reactive toward SO2, enabling efficient dealkalization and transformation into environmentally friendly products with reduced sodium and potassium content.
Solution Approach 2:
The patent fundamentally changes the chemical parameters of red mud by removing alkaline components through SO2 reaction. This transforms the material from a highly alkaline, polluting substance into a low-alkalinity, environmentally safe product suitable for various applications, while simultaneously recovering valuable metals.
4Quantity of substance
If metal resources in red mud are not utilized, then red mud can be stockpiled, but metal resources are wasted
Solution Approach 1:
The patent extracts valuable metal resources including aluminum, iron, titanium, and rare earth elements from red mud through the SO2 dealkalization process. These metals are separated and recovered as by-products, converting the previously wasted metal content into recoverable resources that can be utilized in various industrial applications.
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 method achieves deep desulfurization and comprehensive utilization of red mud resources with low energy consumption, low costs, and easy industrial implementation, effectively dealkalizing red mud and recovering metal resources, while treating sulfur-containing waste gases.
Implementation Method 1
introducing SO2 and O2 for aeration oxidation to obtain a red mud mixture
Implementation Method 2
dissolving the red mud in slurry liquid, where the slurry liquid is water and/or alkaline leachate obtained after filtering
Implementation Method 3
adjusting pH of the acidic leachate obtained by filtering to a strongly alkaline level to obtain alkaline leachate
Data Source
AI summary
The present invention discloses a method for aluminum-enhanced dealkalization of red mud and separation and recovery of aluminum and iron. The method includes: dissolving red mud in water, introducing excessive SO2, introducing O2 for aeration, and refluxing part of alkaline leachate after filtering; when pH of a red mud mixture decreases to below 3, washing and filtering the red mud mixture, adding NaOH to acidic leachate to adjust its pH to a strongly alkaline level, aging and filtering the leachate, treating filter residue to recover Fe2O3, and refluxing part of alkaline leachate after filtering to the red mud mixture; and adjusting pH of the remaining alkaline leachate after filtering to a weakly acidic level, and conducting filtering to recover aluminum.