Effects of Mechanical Activation on the Bioleaching of Sphalerite and Marmatite for Zn Extraction

Shusheng Li,Anni Tang,Yisheng Zhang,Yu Zhao,Xin Lv,Hongbo Zhao,Li Shen,Guanzhou Qiu,Luyuan Zhang

doi:10.3390/min11020111

Abstract

Even though mechanical activation is a significant pretreatment technology for the efficient extraction of metals from mineral resources, its effects on the bioleaching of sphalerite and marmatite are rarely discussed. In this study, mechanical activation pretreatment using various grinding media and grinding times was conducted, and particle size distribution, morphology, X-ray diffraction (XRD) and energy dispersive spectrometry (EDS) analyses, as well as batch bioleaching experiments, were carried out. The results suggest that #C conditions (corundum jar with zirconia balls) were more efficient than #S conditions (stainless steel jar with stainless steel balls) for the grinding of both sphalerite and marmatite. Mechanical activation significantly improved the bioleaching of sphalerite; however, it inhibited that of marmatite, possibly due to the formation of reactive oxygen species (ROS). The optimum grinding conditions for the bioleaching of sphalerite and marmatite are proposed.

Highlights

Even though mechanical activation is a significant pretreatment technology for the efficient extraction of metals from mineral resources, its effects on the bioleaching of sphalerite and marmatite are rarely discussed
The results show that the pH values rose sharply on day 1, accentuating proton consumption during the initial rapid dissolution of both sphalerite and marmatite
Under the #S conditions, the Zn recoveries of sphalerite were proportional to the grinding time, and the particle size was inversely proportional to the grinding time (Figure 2a–c)

Summary

Introduction

Even though mechanical activation is a significant pretreatment technology for the efficient extraction of metals from mineral resources, its effects on the bioleaching of sphalerite and marmatite are rarely discussed. Zinc sites in the lattice structure of sphalerite can be substituted by multiple impurity ions, especially iron ions [4] Marmatite (Znx Fe1-x S). Occurs when the iron content reaches 6% (commonly, the Fe content is 6% to 25%, but can be even greater) [5] Both sphalerite and marmatite have similar cubic crystalline structures [6,7], but the lattice dimensions decrease when the iron content increases [8]. The conductivity, surface hydrophobicity, and surface defects of sphalerite/marmatite increase when the iron content increases [6,8], significantly affecting their flotation and metal extraction

Methods

Results

Discussion

Conclusion