A mild and highly effective method of leaching metal from chalcopyrite using household chemicals

TL;DR

This paper presents a safe and effective method to extract copper from chalcopyrite using common, non-toxic chemicals at room temperature.

Contribution

A green leaching method using acetic acid and hydrogen peroxide achieves 100% copper recovery from chalcopyrite under mild conditions.

Findings

100% copper recovery was achieved using acetic acid and hydrogen peroxide at room temperature.

Planetary ball milling pretreatment enhanced leaching efficiency without additional reagents.

No passivation or inhibition was observed in the leaching process using this method.

Abstract

While chalcopyrite is the most abundant natural source of Cu on Earth, its chemical inertness hinders the practical accessibility of this copper. Many current novel leaching methods rely on using relatively hard (and toxic) compounds (e.g., H2SO4 and ethylene glycol) and/or reaction conditions to overcome this inertness; however, this results in significant operational hazards and environmental pollution. To address these concerns and in accordance with Green Chemistry principles, we report an environmentally benign leaching system using acetic acid and hydrogen peroxide that enables complete copper recovery at room temperature. Moreover, an environmentally benign planetary ball milling pretreatment was used to degrade the chemical inertness of chalcopyrite in a sustainable way without the need for additional chemical reagents. Ball-milling speed, acetic acid volume, reaction temperature, and reaction duration were varied to achieve optimal leaching conditions for both environmental friendliness and energy efficiency. Consequently, a 100% copper recovery rate was achieved under optimal conditions. Notably, neither inhibition of the leaching nor passivation of the chalcopyrite was observed when employing this leaching system. Thus, this leaching system offers significant advantages in both safety and efficacy for the leaching of copper from chalcopyrite.

Through Taguchi experimental design, 100% copper metal recovery from recalcitrant ores is achieved using greener reagents and mild operating conditions, highlighting the role of radical species in hydrometallurgy.

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