Neutralized Slurry Settling Separation for Nickel Oxide Ore
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Solution Overview
Problem
The existing hydrometallurgical processes for nickel oxide ores face challenges in efficiently separating hematite from leach residues and preventing filtration failures due to the generation of gypsum and sulfur dioxide, particularly when using magnesium oxide as a neutralizing agent, which leads to clogging and decreased filtering speed.
Innovation Solution
A settling separation process is implemented using a magnesium oxide as a neutralizing agent in the neutralization step, followed by the addition of a cationic flocculant to the neutralized slurry to improve filterability and effectively separate and remove the neutralized precipitate, thereby preventing filtration failures and achieving high clarity in the mother liquor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnesium oxide is used as a neutralizing agent, then impurity components in leachate can be effectively precipitated, but filtration failure occurs such as clogging of filter cloth and decrease of filtering speed
Solution Approach 1:
A cationic flocculant is introduced as an intermediary substance to bridge the fine neutralized precipitates and facilitate their aggregation. The flocculant acts as a mediator that binds dispersed particles together, forming larger flocs that can be easily separated by filtration, thereby resolving the contradiction between effective precipitation and filtration efficiency
Solution Approach 2:
The patent changes the chemical parameter by adding a cationic flocculant that alters the surface charge and aggregation behavior of the precipitated particles. This parameter change transforms the fine, filter-clogging precipitates into larger, filterable flocs, maintaining precipitation efficiency while improving filtration speed
2Manufacturing precision
If magnesium oxide is used as a neutralizing agent, then impurity components can be precipitated, but neutralized precipitate mixes into supernatant as SS causing further filtration failure
Solution Approach 1:
The cationic flocculant serves as an intermediary that captures fine precipitate particles and suspended solids, binding them into larger aggregates. This mediator prevents the fine particles from remaining dispersed in the supernatant, ensuring complete precipitation while maintaining filtration stability by removing all suspended solids in one process step
3Ease of manufacture
If Ca-based neutralizing agent is used, then neutralization can be performed, but large amount of gypsum is generated requiring large equipment for solid-liquid separation
Solution Approach 1:
The patent extracts the gypsum generation problem by replacing the Ca-based neutralizing agent with a Mg-based alternative. This substitution removes the source of gypsum precipitation, eliminating the need for large-scale solid-liquid separation equipment while maintaining effective neutralization capability
Solution Approach 2:
The patent changes the chemical composition parameter by substituting calcium-based reagents with magnesium-based reagents. This parameter change alters the precipitation chemistry to avoid gypsum formation, thereby simplifying the separation equipment requirements while preserving neutralization effectiveness
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 separates and removes the neutralized precipitate, inhibits filtration failures, and improves filterability, resulting in a high-clarity mother liquor for nickel and cobalt recovery with enhanced productivity.
Implementation Method 1
performing a neutralization step for a leachate by using a magnesium oxide to obtain a neutralized slurry
Implementation Method 2
separating and removing a neutralized precipitate by adding a cationic flocculant into the neutralized slurry
Implementation Method 3
settling separation process for a neutralized slurry
Data Source
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AI summary
An object of the present invention is to provide a settling separation process for a neutralized slurry in which a neutralization step is efficiently performed for a leachate obtained by the leaching of nickel and cobalt from a nickel oxide ore, and further a neutralized precipitate obtained by precipitation of impurity components can effectively be separated and removed while inhibiting the filtration failure; and to provide a hydrometallurgical process for a nickel oxide ore, in which the above process is applied. In the present invention, a neutralization step is performed by using a magnesium oxide for a leachate obtained by the leaching of nickel and cobalt from a nickel oxide ore to obtain a neutralized slurry, and a neutralized precipitate is separated and removed by the addition of a cationic flocculant into the neutralized slurry.