A Comparative Study on the Effect of Flotation Reagents on Growth and Iron Oxidation Activities of Leptospirillum ferrooxidans and Acidithiobacillus ferrooxidans

Mohammad Jafari,Mahdi Gharabaghi,Saeed Chehreh Chelgani,Said Shafaei,Hadi Abdollahi

doi:10.3390/min7010002

Abstract

Recently, extraction of metals from different resources using a simple, efficient, and low-cost technique-known as bioleaching-has been widely considered, and has turned out to be an important global technology. Leptospirillum ferrooxidans and Acidithiobacillus (Thiobacillus) ferrooxidans are ubiquitous bacteria in the biomining industry. To date, the effects of commercial flotation reagents on the biooxidation activities of these bacteria have not been thoroughly studied. This investigation, by using various systematic measurement methods, studied the effects of various collectors and frothers (collectors: potassium amylxanthate, potassium isobutyl-xanthate, sodium ethylxanthate, potassium isopropylxanthate, and dithiophosphate; and frothers: pine oil and methyl isobutyl carbinol) on L. ferrooxidans and A. ferrooxidans activities. In general, results indicate that in the presence of these collectors and frothers, L. ferrooxidans is less sensitive than T. ferrooxidans. In addition, the inhibition effect of collectors on both bacteria is recommended in the following order: for the collectors, potassium isobutyl-xanthate > dithiophosphate > sodium ethylxanthate > potassium isobutyl-xanthate > potassium amylxanthate; and for the frothers, methyl isobutyl carbinol > pine oil. These results can be used for the optimization of biometallurgical processes or in the early stage of a process design for selection of flotation reagents.

Highlights

IntroductionThe main purposes for addition of reagents into the process are providing the highest selectivity (grade) and concentration results (recovery)
Reagents play essential roles during mineral separation by flotation.The main purposes for addition of reagents into the process are providing the highest selectivity and concentration results
The deviation of pH from the control test (∆pH ) in the presence of various collectors (Figure 1a–e) shows increases in the ∆pH during the first 2 days of L. ferrooxidans and A. ferrooxidans activities in all tests (+∆pH ). These increases are higher in the presence of L. ferrooxidans than in A. ferrooxidans tests (Figure 1c,d)

Summary

Introduction

The main purposes for addition of reagents into the process are providing the highest selectivity (grade) and concentration results (recovery). They react with the surface of the target minerals and—based on their properties—change the hydrophobicity of mineral surfaces (i.e., collectors and depressants), or reduce the surface tension of pulp by providing a large air–water interface (i.e., frothers). The residual of these reagents remains on the surface of products (concentrate and tail). The presence of these residual surfactants on flotation products has no essential effect on the pyrometallurgical extractions [1], they may have

Methods

Results

Conclusion