Hydrometallurgical Sulfurizing Agent Removal via Leaching Residue
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Solution Overview
Problem
The existing methods for removing hydrogen sulfide from barren liquor in the hydrometallurgical process of nickel oxide ore require excessive amounts of sulfuric acid and neutralizing agents, increasing treatment costs due to the presence of impurities in the precipitate used as a source of trivalent iron ions.
Innovation Solution
The method involves adding a leaching residue obtained from the leaching step as a source of trivalent iron ions to the barren liquor, along with a sulfuric acid solution, to achieve a specific pH range and air flow rate, effectively immobilizing hydrogen sulfide as sulfur, thereby reducing the amount of sulfuric acid and neutralizing agents needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precipitate by neutralization is used as a source of trivalent iron ions for removing hydrogen sulfide from barren liquor, then hydrogen sulfide removal is achieved, but excessive amounts of sulfuric acid and neutralizing agents are consumed due to impurities in the precipitate
Solution Approach 1:
The invention extracts and utilizes the leaching residue, which contains trivalent iron ions, directly from the HPAL process as the source for hydrogen sulfide removal, rather than using precipitate by neutralization that contains impurities. This extraction of the useful component (trivalent iron) from the original leaching residue avoids the impurity problem while maintaining removal efficiency.
Solution Approach 2:
The leaching residue serves multiple functions: it acts as a source of trivalent iron ions for hydrogen sulfide removal and simultaneously functions as a washing liquid for the leaching residue washing step. This multi-functionality reduces overall chemical consumption and improves process efficiency.
2Productivity
If barren liquor is used as washing water for leaching residue, then water utilization is improved, but hydrogen sulfide odor and safety issues arise due to insufficient decomposition and removal of dissolved hydrogen sulfide
Solution Approach 1:
The invention performs preliminary removal of hydrogen sulfide from the barren liquor by adding leaching residue containing trivalent iron ions before the barren liquor is used as washing water. This preliminary action ensures that hydrogen sulfide is decomposed and removed in advance, eliminating odor and safety hazards while maintaining water utilization benefits.
Solution Approach 2:
The invention converts the harmful dissolved hydrogen sulfide in barren liquor into beneficial sulfur precipitate through oxidation by trivalent iron ions. The hydrogen sulfide, which causes odor and safety issues, is transformed into a removable solid form while the oxidized barren liquor becomes suitable for reuse as washing water.
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 efficiently decreases the usage of sulfuric acid and neutralizing agents while effectively removing hydrogen sulfide, optimizing the treatment process and reducing costs.
Implementation Method 1
a source of trivalent iron ions is added to a barren liquor... and hydrogen sulfide dissolved in the barren liquor is reacted with the trivalent iron to immobilize the hydrogen sulfide dissolved in the barren liquor into the form of sulfur
Data Source
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AI summary
Provided is a method for removing a sulfurizing agent such as hydrogen sulfide or the like that is dissolved in a sulfidized liquid generated in a hydrometallurgical process for a nickel oxide ore, the method enabling the usage quantities of chemical agents such as sulfuric acid and neutralizing agents to be reduced while a dissolved sulfurizing agent is effectively removed. This method for removing a sulfurizing agent includes: subjecting a nickel oxide ore to acid leaching at high temperature and high pressure using sulfuric acid so as to obtain a leachate containing nickel and cobalt and a leaching residue; subjecting the leachate to a sulfurizing treatment by means of a sulfurizing agent so as to generate a sulfide containing nickel and cobalt and a sulfidized liquid; and removing the sulfurizing agent dissolved in the separated sulfidized liquid. A washed leaching residue, which is obtained by washing the leaching residue, and a sulfuric acid solution are added to the sulfidized liquid so as to solidify and recover sulfurizing agent contained in the sulfidized liquid as sulfur.