Polymetallic Nodule Processing Magnesium Removal
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Solution Overview
Problem
Existing processes for recovering metals from polymetallic nodules, such as nickel, cobalt, and manganese, face inefficiencies due to decreased performance over time and the accumulation of magnesium, which hinders the extraction of target metals and increases reactant consumption.
Innovation Solution
A process involving the use of an acidic solution to selectively remove magnesium from polymetallic nodules, followed by reductive leaching and solvent extraction to improve metal recovery, including the recycling of leachate streams to adjust metal ratios and reduce magnesium content, thereby enhancing the efficiency of metal extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If reductive leaching is performed continuously to recover metals, then metal recovery is achieved, but magnesium accumulates in the leachate stream and hinders extraction of target metals
Solution Approach 1:
The patent extracts magnesium from the leachate stream using solvent extraction with a specific organic solvent that selectively extracts magnesium while leaving target metals in the aqueous phase. This removes the harmful magnesium accumulation that hinders metal extraction.
Solution Approach 2:
The patent introduces an intermediary organic solvent phase that mediates between the aqueous leachate and the solid nodule material. This intermediary phase selectively removes magnesium through solvent extraction, enabling continuous metal recovery without magnesium buildup.
2Productivity
If leachate is recycled to maintain metal ratios, then extraction efficiency improves, but reactant consumption increases due to magnesium presence
Solution Approach 1:
The patent removes magnesium from the recycled leachate stream through solvent extraction, preventing it from consuming reactants during recycling. This maintains extraction efficiency while reducing unnecessary reactant consumption that would occur if magnesium were present in the recycle stream.
3Productivity
If acidic solution is used to remove magnesium, then magnesium extraction is improved, but co-extraction of valuable metals occurs
Solution Approach 1:
The patent applies local quality by using a selectively extractable organic solvent that has different extraction characteristics for magnesium versus valuable metals. The solvent is specifically suited to extract magnesium while leaving nickel, cobalt, and other valuable metals in the aqueous phase, thus removing magnesium without causing co-extraction of target metals.
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 improves the reliability and efficiency of metal recovery by controlling magnesium levels and optimizing metal ratios, leading to increased yields and reduced waste, particularly in the extraction of nickel, cobalt, and manganese.
Implementation Method 1
contacting the one or more polymetallic nodules to an acidic solution, thereby extracting one or more magnesium-containing components from the one or more polymetallic nodules
Implementation Method 2
performing a reductive leaching process on the polymetallic nodules after separating the portion of the acidic solution from the one or more polymetallic nodules
Data Source
AI summary
The present disclosure is directed, in certain embodiments, to processes for recovering metals from polymetallic nodules. The processes may include one or both of (i) a weak acid wash of the polymetallic nodule material and (ii) nano-filtration and/or limestone neutralization of recycled manganese-rich stream to remove magnesium from process streams to improve the recovery of target metals, including manganese. The processes may include cobalt and/or nickel solvent extraction to improve metal(s) recovery.