Development of cementation-magnetic separation method for sulfide mineral processing and AMD prevention

The Challenge

Sulphide minerals are major sources of valuable metals such as gold, copper, lead, and zinc. Therefore, the separation of sulphides has been an important process not only to increase the recovery value of metals but also to prevent AMD formation from tailings [1-6]. Flotation is widely used to separate sulphide minerals such as pyrite (FeS2), arsenopyrite (FeAsS), chalcopyrite (CuFeS2), and sphalerite (ZnS) from other minerals. However, separating one sulphide mineral from another sulphide mineral is still a challenge.

A number of research methods have been explored to carry out selective flotation of sulphides and these include using oxidants [1], the use of novel collectors [2], and the use of additional reagents like zinc sulphate [3]. These studies still face difficulties due to similar flotation behaviour in the absence of additional reagents and poor selectivity. Therefore, developing alternative methods is essential to selectively remove or recover the target sulphide mineral.

Proposed Solution

This study will develop a new mineral processing method for the separation of sulphides using a combination of cementation and magnetic separation. Through the cementation, precipitates of magnetic elements (e.g. Co, Ni) are formed on the surface of sulphide, so that the sulphide could be selectively separated by magnetic separation.

Proposed Benefits to WA

Flotation becomes more challenging when the ore complex has similarities in surface characteristics. The process is widely used in WA due to the prevalence of sulphide minerals found in the state (gold, nickel, copper-zinc). It is considered as an expensive process compared to other physical separation processes. The new concept suggested in this study offers a novel alternative to separate sulphide minerals. Although most sulphides are nonmagnetic, the proposed method can render them magnetic, and subsequently make them amenable for magnetic separation. The new process is a more flexible and simple method for the separation of sulphides in various conditions. It can offer the benefit of managing tailings which is a concerning issue in WA, particularly the AMD-forming sulphides. Therefore, pollution due to heavy metal contamination can be prevented. More importantly, it is envisaged that the new method can offer solutions to increase recovery and productivity in mineral processing.

Project Duration

3 years and 6 months. Scholarship year of award 2023.