Hydrometallurgical Nickel Cobalt Extraction from Laterite Ores
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Solution Overview
Problem
Current hydrometallurgical and pyrometallurgical methods for nickel and cobalt extraction from laterite ores are energy and capital cost intensive, unsuitable for processing low-grade ores, and face challenges with high acid consumption and permeability issues due to clay components in heap leaching, leading to rejection of coarse laterite fractions and reduced recovery rates.
Innovation Solution
A hydrometallurgical method involving beneficiation to separate fine and coarse ore fractions, pressure acid leaching, agglomeration of coarse ore, and heap leaching with free acid from the pressure acid leaching step, allowing for co-processing of both fractions without clay removal or acid supplementation, and utilizing counter-current decantation for efficient liquor distribution and neutralization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If pressure acid leaching is used to extract nickel and cobalt, then extraction efficiency is improved, but acid consumption increases and operational costs increase
Solution Approach 1:
The patent recovers and reuses acid from the leaching process by treating pregnant leach solution to recover nickel and cobalt, then recycling the regenerated acid back to the pressure acid leaching step, thereby reducing fresh acid consumption while maintaining extraction efficiency
Solution Approach 2:
The acid solution serves multiple functions: it acts as the leaching agent in pressure acid leaching, provides irrigation water for heap leaching, and after metal recovery, becomes regenerated acid for reuse, creating a multi-functional circular system that reduces overall acid consumption
2Adaptability or versatility
If heap leaching is used to process coarse laterite fraction, then processing capability is improved, but clay components reduce heap permeability and leach solution flow
Solution Approach 1:
The patent uses the clay-containing coarse laterite fraction that would normally be rejected as waste and stockpiled, transforming it into a valuable resource by processing it through agglomeration and heap leaching to recover nickel and cobalt, thereby converting a harmful waste stream into a beneficial product source
Solution Approach 2:
The patent applies agglomeration treatment to the coarse laterite fraction, changing its physical parameters by binding fine particles together into larger agglomerates with improved porosity and permeability, enabling effective heap leaching despite the presence of clay components
3Ease of manufacture
If coarse laterite fraction is rejected and stockpiled, then processing simplicity is maintained, but nickel and cobalt recovery is reduced
Solution Approach 1:
The patent segments the laterite ore into fine and coarse fractions through beneficiation, then processes each fraction through optimized pathways (fine fraction through pressure acid leaching, coarse fraction through agglomeration and heap leaching), maximizing overall metal recovery while maintaining operational simplicity through modular processing
Solution Approach 2:
The patent merges the processing of fine and coarse laterite fractions into a unified hydrometallurgical flow sheet where both streams are processed and their pregnant leach solutions are combined for metals recovery, ensuring comprehensive nickel and cobalt recovery from the entire ore stream
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 enables effective extraction of nickel and cobalt from both fine and coarse laterite fractions, reducing waste, increasing recovery rates, and minimizing energy and operational costs, while maintaining heap permeability and reducing neutralization expenses.
Implementation Method 1
Passing the fine ore fraction to a pressure acid leaching step in which a sulphuric acid lixiviant is used to extract nickel and cobalt values forming a leach slurry
Implementation Method 2
Leaching the coarse ore fraction in the heaps with liquor separated in step (v) wherein the leaching agent is the free acid remaining therein from the pressure acid leaching step (ii)
Implementation Method 3
Passing at least a portion of the coarse ore fraction to an agglomeration step in which the coarse ore fraction is agglomerated
Implementation Method 4
Passing the leach slurry from the pressure acid leach step (ii) to a solid/liquid separation step
Data Source
Figure 1
AI summary
A hydrometallurgical method (10) for the extraction of nickel and cobalt from laterite ores, the method characterised by the method steps of: (i) Beneficiating (14, 16) a run of mine laterite ore containing nickel and cobalt into a substantially fine ore fraction and a substantially coarse ore fraction; (ii) Passing the fine ore fraction to a pressure acid leaching step (26) in which a sulphuric acid lixiviant is used to extract nickel and cobalt values forming a leach slurry comprising liquor and residue solids components; (iii) Passing at least a portion of the coarse ore fraction to an agglomeration step (22) in which the coarse ore fraction is agglomerated; (iv) Forming at least one heap (40, 48) from the agglomerated ore of step (iii); (v) Passing the leach slurry from the pressure acid leach step (ii) to a solid/liquid separation step (28), from which the residue solids are passed to waste (30), a proportion of the liquor is passed to further processing for metals recovery (34) and a further portion of the liquor is passed directly or indirectly to the or each heap (40, 48) formed in step (iv); (vi) Leaching the coarse ore fraction in the heaps (40, 48) with liquor separated in step (v) wherein the leaching agent is the free acid remaining therein from the pressure acid leaching step (ii); and (vii) Passing pregnant leach solution from the or each heap (40, 48) to metals recovery (34).