Hydrometallurgical Recycling Process for Mobile Phone Printed Circuit Boards Using Ozone

Magdalena Lisińska,Mariola Saternus,Silvie Brožová,Gražyna Simha Martynková,Aleš Slíva,Bernadeta Gajda

doi:10.3390/met11050820

Abstract

Printed circuit boards (PCBs) can be an important source of non-ferrous metals (Al, Sn, Zn, and Ni) and precious metals (Au, Ag, Cu, and Pd). With the continuous increase in demand for metals due to the depletion of ores, recycling of this waste is becoming an attractive alternative. The printed circuits also contain hazardous metals, such as Pb, Hg, As, and Cd. Due to the huge increase in the amount of e-waste, the processing of printed circuit boards for metal recovery and proper handling of hazardous substances has a positive effect on the environment. Pyrometallurgical and hydrometallurgical methods are used for the treatment of this waste. Various oxidizing agents are used in the hydrometallurgical processes, including ozone. PCBs from mobile phones were assessed for the recovery of Cu, Sn, and precious metals. The ground and sieved materials were leached in nitric acid, hydrochloric acid, and sulfuric acid at various process parameters, such as leaching time, leaching agent, and temperature. It was found that the best result was obtained using hydrochloric acid with the addition of ozone at 353 K for a period of 4 h to obtain 68.45 g/dm3 of copper. Preliminary results of electrolysis and cementation are also presented.

Highlights

The increasingly shorter life cycle of electrical and electronic devices forces society to frequently change these devices to new ones with different, better, and versatile functions.old equipment waste is one of the fastest generated waste groups in the world [1]
Next to the oxidants, is a popular leaching agent that has the ability to react with metals, used among others to recover metals from ores
The leaching process of printed circuit boards was carried out using acid mixtures with ozone known for strong oxidizing properties and the ability to react with metals

Summary

Introduction

The increasingly shorter life cycle of electrical and electronic devices forces society to frequently change these devices to new ones with different, better, and versatile functions.old equipment waste is one of the fastest generated waste groups in the world [1]. Electronic waste (e-waste) includes any large or small electrical and electronic device that a user has disposed of or has somewhere at home. Are classified as large devices, while small devices include mobile phones, laptops, tablets, etc. Regardless of their size, most electronic devices contain a printed circuit board. This tile is a valuable element of each of these devices because it contains metals that are attractive in terms of recycling, including gold, silver, palladium, and copper [3]. There are hazardous metals, including lead and mercury, in printed circuits that can have a negative impact on the environment [4]. The storage and incineration of this waste generate dangerous products and gaseous emissions, which pose a serious threat to human health, the environment, and sustainable economic growth [13,14,15]

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Results

Conclusion