Selective gold extraction from electronic waste using high-temperature-synthesized reagents
Jinlin Li1, Chunbao Sun1,2, Peilong Wang1,2
1School of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
Environmental Science and Pollution Research International
|December 29, 2023
Summary
A novel, low-toxicity gold extraction reagent was developed using urea, sodium carbonate, and an iron salt. Synthesized at 800°C, it efficiently extracts gold from electronic waste with minimal cyanide by-products.
Area of Science:
- Materials Science
- Environmental Chemistry
- Metallurgical Engineering
Background:
- Cyanide is the traditional gold extraction reagent but poses significant toxicity risks.
- Existing low-toxicity alternatives have limitations for industrial application.
- Sustainable gold production requires development of efficient, less toxic leaching agents.
Purpose of the Study:
- To synthesize and evaluate a novel, efficient, and low-toxicity gold extraction reagent.
- To investigate the reagent's leaching performance under various synthesis conditions.
- To assess the generation of free cyanide and the reagent's toxicity.
Main Methods:
- High-temperature synthesis of a novel reagent from urea, sodium carbonate, and an iron salt.
- Evaluation of leaching ability with varying synthesis parameters.
- Analysis of free cyanide generation and toxicity.
- Testing selectivity on electronic waste (CPU pins).
Main Results:
- Reagents synthesized with potassium ferrocyanide or ferricyanide showed comparable gold leaching.
- Synthesis at 800°C resulted in lower free cyanide levels and reduced toxicity.
- The reagent exhibited high selectivity for gold, with minimal dissolution of other metals.
- Optimal conditions achieved 94.65% gold extraction efficiency from CPU pins.
Conclusions:
- The novel reagent offers an efficient and low-toxicity alternative for gold extraction.
- High-temperature synthesis (800°C) is key to minimizing cyanide by-products and toxicity.
- The reagent shows significant potential for sustainable gold recovery from electronic waste and concentrates.
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