Reclamation of steel shots by acid leaching for powder metallurgy applications

Yu Jun Jie,Zahid A Khan,Abdulrahman Al-Ahmari,Mazli Mustapha,Namrata Gangil,Shahrul Kamaruddin,Mustufa Haider Abidi,Arshad Noor Siddiquee

doi:10.1177/1687814019866961

Abstract

Acid leaching is extensively employed for extractive metallurgy, but its use on reclamation of shot blasting media has not been extensively studied. The parameters of acid leaching process such as rate of stirring, the leached material grain size, the solid (material) to liquid (acid) ratio, type of acid, concentration of acid, leaching temperature, and leaching duration govern the effectiveness of this process. The goal of this article is to investigate the effectiveness of acid leaching to recover the iron from used shot blasting media. Influence of varying leaching durations on the recovery percentage of iron from the used shot blasting media is investigated, and it is found that acid leaching can remove impurities from used shot blasting media and it can successfully recover 73.6% of iron on the particle surface level and 44.3% of iron overall. Hence, it is a feasible process for recovery of iron from used shot blasting media.

Highlights

Shot blasting is a process of impinging target surface with a stream of metallic blasting media under immense pressure
This article presented an experimental investigation to reveal the effectiveness of the acid leaching process in removing impurities and recovering iron from used shot blasting media
Based on the results of the present investigation, following conclusions are drawn: 1. Acid leaching is an efficient and effective process for recovering iron from used shot blasting media as the percentage of recovery from the surface of the shot blasting media is found to be as high as 73.6%

Summary

Introduction

Shot blasting is a process of impinging target surface with a stream of metallic blasting media (shots) under immense pressure. This process utilizes pressurized fluids from centrifugal wheel to propel the blasting media.[1] It is used in common applications such as smoothening the surfaces, removing rust or old paint from the surfaces, reclamation of metals from e-waste, and cleaning of heat exchanger fouling. The cleaned contaminants reported to incur cost as much as 0.25% of gross domestic product (GDP) and 2.5% additional release of CO2.2 Shot blasting process generates a mixture of used blasting media and waste from the cleaned surface which needs to be suitably disposed.[3] Waste from the blasting media contains valuable metals such as iron, and its disposal without recovery brings adverse economic and environmental impact.[4] Disposal recycling of used media involves additional processing energy and destroys primary energy

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