Solvent Extraction Purification of Manganese Pregnant Leach Solution
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Solution Overview
Problem
Conventional methods for purifying manganese pregnant leach solution (PLS) to produce high purity manganese sulphate monohydrate (HPMSM) are energy-intensive and inefficient in removing impurities such as calcium and magnesium, which are essential for achieving the desired product specifications.
Innovation Solution
A method utilizing solvent extraction (SX) to purify manganese PLS, involving steps such as mixing the PLS with an organic solvent and an alkaline solution, allowing the mixture to become quiescent to form a loaded organic phase, performing SX scrubbing with acid solutions to remove impurities, and finally stripping the manganese content into a clean aqueous phase for crystallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional chemical precipitation methods are used to remove calcium and magnesium impurities, then impurity removal is attempted, but the product manganese sulphate monohydrate does not meet specifications for calcium and magnesium content
Solution Approach 1:
The patent applies solvent extraction to selectively separate manganese from calcium and magnesium impurities. An organic solvent system (using hydrocarbons with carboxylic acid or phosphoric acid groups) extracts manganese from the pregnant leach solution, leaving calcium and magnesium in the aqueous phase. This extraction mechanism achieves the required purity specifications that conventional chemical precipitation methods cannot attain.
2Manufacturing precision
If electro-winning is used to produce high purity manganese metal, then product quality is improved, but energy consumption increases significantly
Solution Approach 1:
The patent replaces the electro-winning process (electrical energy-intensive) with a solvent extraction system. The extraction process uses chemical affinity between the organic solvent and manganese ions to achieve separation and concentration, eliminating the need for electrical current while maintaining high product purity. This substitution directly addresses the energy consumption issue while preserving manufacturing precision.
3Productivity
If reductive roasting followed by acid leach is used, then manganese extraction is achieved, but energy-intensive heating and evaporation steps are required
Solution Approach 1:
The patent changes the chemical parameters of the leach solution to enable direct solvent extraction of manganese without requiring reductive roasting. By adjusting pH, oxidizing conditions, and using specific ligands in the leach solution, manganese becomes extractable by the organic solvent system. This parameter modification eliminates the thermal processing steps while maintaining extraction efficiency.
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 removes calcium and magnesium impurities from the manganese PLS, achieving high purity manganese sulphate monohydrate (HPMSM) with impurities below 50 ppm, thereby improving energy efficiency and product quality.
Implementation Method 1
mixing the acidic aqueous PLS with a fixed volume of organic solvent dissolved in an organic diluent and an alkaline solution for Ph control to form a first organic mixture
Implementation Method 2
allowing the first organic mixture to become quiescent for a predetermined amount of time to form a loaded organic phase comprising manganese from the aqueous PLS and a barren aqueous phase or raffinate comprising calcium and magnesium impurities
Implementation Method 3
performing SX stripping of the second scrubbed organic phase by mixing with an acid solution in water, wherein the SX stripping transfers the manganese content of the second scrubbed organic phase into a clean aqueous phase
Data Source
AI summary
Provided is a method for purification of manganese pregnant leach solution (PLS) using solvent extraction (SX). The method broadly comprises the steps of providing a partially purified aqueous pregnant leach solution (PLS), using an SX load stage to form a first organic mixture which forms a loaded organic phase comprising all of the manganese from the PLS, performing two stages of SX scrubbing to form a third organic mixture which is substantially free of impurities, performing SX stripping to transfer the manganese content of the scrubbed organic phase into a clean aqueous phase, and producing high purity manganese sulphate monohydrate (HPMSM) crystals from the clean aqueous phase.