Electrolytic Copper Production Suppressing Silver Elution
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Solution Overview
Problem
Current methods for manufacturing electrolytic copper fail to sufficiently suppress silver (Ag) concentration in the electrolyte during electrolysis of blister copper, leading to incorporation of Ag into the electrolytic copper, which reduces its grade and results in noble metal loss.
Innovation Solution
The method involves performing electrolysis with an anode potential lower than the elution potential of Ag and maintaining a dissolved oxygen concentration of 3 mg/L or less in the sulfuric acid solution, using additives like thiourea or chloride ions to form Ag compounds, and incorporating metals like Pb or Cu to shift the surface potential of Ag particles, thereby suppressing Ag elution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional electrolysis is performed in sulfuric acid electrolyte, then copper refining is achieved, but Ag concentration in electrolyte increases leading to Ag incorporation in electrolytic copper
Solution Approach 1:
The patent applies parameter changes by controlling the anode potential to be lower than the elution potential of Ag, and maintaining dissolved oxygen concentration at 3 mg/L or less. These parameter controls prevent Ag elution from the anode while allowing copper dissolution, thereby suppressing Ag concentration in the electrolyte and preventing Ag incorporation into the electrolytic copper.
Solution Approach 2:
The patent applies local quality by creating different chemical environments in different regions of the electrolyte. Specifically, it controls the anode region to have low dissolved oxygen concentration (3 mg/L or less) and specific anode potential, which suppresses Ag elution locally at the anode interface, while the bulk electrolyte maintains normal electrolysis conditions for copper production.
2Manufacturing precision
If Ag elution is suppressed by controlling anode potential and dissolved oxygen, then Ag grade in electrolytic copper decreases, but recovery rate of Ag increases
Solution Approach 1:
The patent applies the extraction principle by removing Ag from the electrolytic copper product through controlled suppression of Ag elution. By maintaining anode potential below Ag elution potential and dissolved oxygen at 3 mg/L or less, Ag is prevented from entering the electrolyte in the first place, effectively extracting Ag from the copper refining process and directing it to the anode slime for recovery.
Solution Approach 2:
The patent applies feedback by continuously monitoring and controlling the anode potential and dissolved oxygen concentration during electrolysis. The dissolved oxygen concentration is maintained at 3 mg/L or less through controlled aeration or deaeration, and the anode potential is adjusted to remain below the Ag elution potential, creating a feedback-controlled system that prevents Ag incorporation while maintaining efficient copper production.
Data Source
AI summary
Provided is a method for producing electrolytic copper having a low Ag content by successfully suppressing the Ag concentration in an electrolytic solution. The electrolytic copper production method involves a step in which blister copper comprising Ag is used as an anode, and electrolysis is carried out under sulfuric acid acidity while maintaining the anode electric potential at a relatively low electric potential in comparison to the electric potential of the Ag elution.