Red Mud Iron Aluminum Recovery via High-Temp Wet Treatment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The processing of high-iron-content red mud with high alumogoethite content is challenging due to difficulties in digesting boehmite and converting alumogoethite, leading to low Al2O3 content in discharged red mud and inefficient iron separation.
Innovation Solution
A method involving mixing red mud with a circulating mother liquor and an alkaline earth metal compound additive, followed by wet treatment above 260°C, liquid-solid separation, seed precipitation, and iron separation to recover iron and aluminum from the red mud.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If low-temperature Bayer process is used to digest bauxite, then aluminum oxide production is achieved, but boehmite cannot be digested out and alumogoethite cannot be converted, resulting in high Fe2O3 content and low Al2O3 content in discharged red mud
Solution Approach 1:
The patent applies parameter changes by raising the digestion temperature from the conventional low-temperature range (105-150°C) to a high temperature range (200-250°C or higher). This temperature parameter change enables complete digestion of boehmite and conversion of alumogoethite, transforming the red mud composition to achieve Fe2O3 content ≤10% and Al2O3 content ≥15%, thereby resolving the contradiction between production efficiency and composition control.
2Speed
If conventional digestion methods are used, then processing speed is maintained, but iron separation performance is poor and iron concentrate yield is less than 5%
Solution Approach 1:
The patent changes the temperature parameter to above 200°C during digestion, which fundamentally alters the chemical transformation of iron-containing minerals. This enables alumogoethite conversion to magnetic iron oxide and boehmite digestion, resulting in iron concentrate yield increasing from less than 5% to greater than 45%, while maintaining efficient processing speed through optimized high-temperature conditions.
3Quantity of substance
If high-iron-content bauxite is imported to maintain production, then aluminum oxide supply is ensured, but red mud accumulation increases, occupying land and polluting environment
Solution Approach 1:
The patent converts the harmful high-iron-content red mud waste into a beneficial resource by applying high-temperature digestion that transforms alumogoethite into magnetic iron oxide and digests boehmite. This enables the red mud to be processed into valuable iron concentrate (yield >45%) and aluminum-containing solution, thereby eliminating environmental pollution while ensuring aluminum oxide supply continues.
4Use of energy by moving object
If low-temperature digestion is used, then energy consumption is reduced, but alumogoethite conversion and boehmite digestion are incomplete
Solution Approach 1:
The patent optimizes the temperature parameter to a specific high-temperature range (200-250°C or higher) that achieves complete mineral conversion while managing energy consumption efficiently. This parameter change ensures alumogoethite conversion and boehmite digestion completeness, producing red mud with Fe2O3 content ≤10% and Al2O3 content ≥15%, thereby resolving the contradiction between energy use and conversion completeness.
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 effectively recovers iron and aluminum from red mud with high alumogoethite and iron content, improving the yield of iron concentrate and reducing waste, while also facilitating the recycling of red mud.
Implementation Method 1
performing a wet treatment above 260° C. to obtain an ore pulp
Implementation Method 2
mixing the red mud with a circulating mother liquor and an additive, and performing a wet treatment above 260° C.
Implementation Method 3
performing a liquid-solid separation on the ore pulp after the ore pulp is flash evaporated
Implementation Method 4
performing a liquid-solid separation on the ore pulp after the ore pulp is flash evaporated, to obtain a separated iron material and a separated liquid
Implementation Method 5
performing a seed precipitation on the separated liquid after the separated liquid is refined
Data Source
AI summary
The disclosure relates to a method for recovering an iron and aluminum from a red mud, which includes the following steps: providing a red mud, a mass percentage of an alumogoethite is not less than 20% and a mass percentage of Fe2O3 is not less than 40% in the red mud; mixing the red mud with a circulating mother liquor and an additive and performing a wet treatment above 260° C. to obtain an ore pulp; performing a liquid-solid separation on the ore pulp after the ore pulp is flash evaporated, to obtain a separated iron material and a separated liquid; performing a seed precipitation on the separated liquid after the separated liquid is refined, or performing a seed precipitation on the separated liquid after the separated liquid is combined with an existing refined liquid; and, preforming an iron separation on the separated iron material after washed to obtain an iron concentrate. The additive includes an alkaline earth metal compound. The alkaline earth metal compound is at least one of a calcium oxide, a calcium hydroxide, a magnesium oxide and a magnesium hydroxide.