Optimizing the Leaching Parameters and Studying the Kinetics of Copper Recovery from Waste Printed Circuit Boards

Abstract

The study of copper (Cu) recovery is crucial for the entire recovery process of waste printed circuit boards (WPCBs), and Cu can be leached efficiently via a sulfuric acid−hydrogen peroxide (H 2 SO 4 −H 2 O 2 ) system. To achieve high Cu recovery, it is important to evaluate the parameters of the leaching process and understand the Cu leaching kinetics. Applying statistical and mathematical techniques to the leaching process will further benefit the optimization of the Cu leaching parameters. Moreover, the leaching kinetics of Cu in the H 2 SO 4 −H 2 O 2 solution is yet to be fully understood. Hence, in the present work, process parameters, such as temperature, H 2 SO 4 and H 2 O 2 concentrations, solid−liquid ratio, particle size, and stirring speed, were optimized statistically by the response surface methodology (RSM). The results showed that the leaching kinetics conformed to the Avrami model. The maximum Cu leaching efficiency was 99.47%, and it was obtained based on the following optimal conditions: 30.98 °C, 2.6 mol/L H 2 SO 4 , 1.87 mol/L H 2 O 2 , a solid−liquid ratio of 0.05 g/mL, 135 mesh, and 378 rpm. RSM was used for the optimization of the process parameters, and the leaching kinetics in this system was clarified. This study provides an important pathway for the investigation of other metal recoveries from WPCBs.

Environmentally friendly ionic liquid medium based on dicyanamide anion for leaching gold from e‐waste CPUs by iodination

“…The Avrami model describes the dynamic process of crystal nucleus change, which was originally used for crystallization kinetics in solution. However, the leaching process is the reverse process of crystallization, and the model is widely applied to study the effects of the factors (such as concentration, temperature, and time) on the leaching kinetics of various metals and metal oxides 55‐57 . The iodination leaching of gold in the IL [C 2 MIM][N(CN) 2 ] system is a complicated solid‐liquid reaction process.…”

“…However, the leaching process is the reverse process of crystallization, and the model is widely applied to study the effects of the factors (such as concentration, temperature, and time) on the leaching kinetics of various metals and metal oxides. [55][56][57] The iodination leaching of gold in the IL [C 2 MIM][N (CN) 2 ] system is a complicated solid-liquid reaction process. In this study, the Avrami model was used as the leaching kinetic model to investigate the leaching kinetics to determine the relationship between the leaching rate and basic parameters; the form is as follows:…”

Chemical and Microbial Leaching of Valuable Metals from PCBs and Tantalum Capacitors of Spent Mobile Phones

“…Formation of jarosite was observed during the microbial leaching experiment which dominated in experiments with higher material load generating high pH. Studies show that ferric iron precipitation hinders the metal leaching process [ 44 ] by reducing the content of dissolved iron in the culture medium [ 25 ]. This suggests that pulp density plays an important role in metal solubilization from electronic waste, high pulp density has a negative effect on the productivity of microorganisms due to the toxic effect of metallic and non-metallic compounds contained in electronic waste [ 24 ] or oxygen transfer limitation [ 19 ].…”

“…Efficient recycling of WEEE will not only address the environmental issues and supply risk of metals but also create job opportunities for biotechnologists, metallurgists, and skilled workers. Additionally, biotechnological recycling of WEEE in a circular economy approach can contribute to resource extraction from waste without having any related harmful impact on the environment [ 25 ].…”

Leaching of Copper Contained in Waste Printed Circuit Boards, Using the Thiosulfate—Oxygen System: A Kinetic Approach

“…Some researchers have used nitric acid and obtained recoveries of up to 99.9% without dissolution of the gold involved and also using oxidants such as ozone or H 2 O 2 [ 32 , 33 , 34 , 35 ]. Others have used sulfuric and hydrochloric acids to recover Cu from WPCBs and have had adequate results [ 36 , 37 , 38 ].…”