Metal Sulfate Crystallization With Impurity Pre-Leaching
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Solution Overview
Problem
The presence of calcium, magnesium, and/or lithium impurities in feedstocks for producing crystallized metal sulfates used in batteries leads to processing difficulties such as contamination, higher energy consumption, and unwanted solids formation due to low solubility of calcium sulfate salts, resulting in supersaturated process streams.
Innovation Solution
A treatment process involving pre-leaching with a lixiviant to selectively extract a first portion of impurities, refining to remove a second portion, and crystallizing the metal sulfate from a leached solution, with optional basification of mother liquor to convert remaining impurities to basic metal salts for reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sulfate-media based processes are used to produce crystallized metal sulfates, then the production efficiency is improved, but calcium sulfate low solubility causes unwanted solids formation and process stream supersaturation
Solution Approach 1:
The patent extracts calcium and magnesium impurities from the feedstock through pre-leaching with sulfuric acid before the main sulfate production process. This removal of harmful calcium prevents subsequent calcium sulfate precipitation and solids formation in the crystallization process, while maintaining high production efficiency.
Solution Approach 2:
The patent performs preliminary leaching treatment to convert calcium and magnesium impurities into soluble sulfate forms and remove them from the feedstock before the main crystallization process. This preliminary action prevents the formation of unwanted calcium sulfate solids during subsequent processing steps.
2Device complexity
If impurities are not removed from feedstock, then the process complexity is reduced, but product contamination increases
Solution Approach 1:
The patent segments the impurity removal process into distinct stages: pre-leaching with sulfuric acid to extract calcium and magnesium, followed by filtration to separate solids, and then the main crystallization process. This segmentation effectively removes impurities to ensure product purity while maintaining manageable process complexity through systematic step-by-step treatment.
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 process effectively reduces impurities, improving the purity and efficiency of crystallized metal sulfates production by minimizing contamination and energy consumption, and enabling the reuse of impurities as neutralizing agents.
Implementation Method 1
pre-leaching the feedstock with a lixiviant to selectively extract a first portion of the impurities from the feedstock
Implementation Method 2
crystallizing the metal sulfate from the leached solution to form a crystallized metal sulfate
Implementation Method 3
basifying a portion of the mother liquor to convert the remaining impurities to a basic metal salt
Data Source
AI summary
A treatment process for crystallizing a metal sulfate involving pre-treating a feedstock comprising calcium, magnesium, and/or lithium impurities, the pre-treating involving pre-leaching the feedstock in the presence of a lixiviant, selectively extracting a first portion of any of the impurities from the feedstock, and forming a leached solution comprising an uncrystallized metal sulfate and any remaining impurities; and/or refining the leached solution and removing a second portion of any of the remaining impurities; and crystallizing the uncrystallized metal sulfate from the leached solution to form a crystallized metal sulfate. So processed, the crystallized metal sulfate may be battery-grade or electroplating-grade.