Effects of Conventional Flotation Frothers on the Population of Mesophilic Microorganisms in Different Cultures

Abstract

Bioleaching is an environment-friendly and low-investment process for the extraction of metals from flotation concentrate. Surfactants such as collectors and frothers are widely used in the flotation process. These chemical reagents may have inhibitory effects on the activity of microorganisms through a bioleaching process; however, there is no report indicating influences of reagents on the activity of microorganisms in the mixed culture which is mostly used in the industry. In this investigation, influences of typical flotation frothers (methyl isobutyl carbinol and pine oil) in different concentrations (0.01, 0.10, and 1.00 g/L) were examined on activates of bacteria in the mesophilic mixed culture (Acidithiobacillus ferrooxidans, Leptospirillum ferrooxidans, and Acidithiobacillus thiooxidans). For comparison purposes, experiments were repeated by pure cultures of Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans in the same conditions. Results indicated that increasing the dosage of frothers has a negative correlation with bacteria activities while the mixed culture showed a lower sensitivity to the toxicity of these frothers in comparison with examined pure cultures. Outcomes showed the toxicity of Pine oil is lower than methyl isobutyl carbinol (MIBC). These results can be used for designing flotation separation procedures and to produce cleaner products for bio extraction of metals.

Variable importance assessments of an innovative industrial-scale magnetic separator for processing of iron ore tailings

“…The absolute value of r shows the strength of correlation between two variables (a larger absolute value indicating stronger interdependence), while its sign indicates their relationship magnitude. In general, | r | > 0.5 shows that there is a significant linear correlation between two variables, which is calculated based on the following equation (Chelgani et al 2016b; Matin et al 2018; Jafari et al 2019b). …”

“…For ranking operating variables by RF, the permutation accuracy importance measurement (PAIM), which is an advanced non-linear tool for VIM, is used. The PAIM for VIM compares the differences between the prediction accuracy of a tree before and after random permutation of the target variable (Matin et al 2016; Matin and Chelgani 2016; Chelgani et al 2016a, 2016b; Shahbazi et al 2017; Chelgani and Matin 2018; Matin et al 2018; Nazari et al 2019; Tohry et al 2019; Jafari et al 2019a, 2019b). The final ranking of variables is based on the computed average of differences over all trees.…”

“…Additional testing proved a reverse flotation addition would produce an even better quality final product and enable eliminating the roasting step. Chelgani et al 2016aChelgani et al , 2016bShahbazi et al 2017;Chelgani and Matin 2018;Matin et al 2018;Nazari et al 2019;Tohry et al 2019;Jafari et al 2019aJafari et al , 2019b 2018; Matin et al 2018;Nazari et al 2019;Tohry et al 2019;Jafari et al 2019aJafari et al , 2019b.…”

“…RF can eliminate the imprecision and uncertainty of complex linear and non-linear relationships for VIM. Although RF for VIM has been used in several mining area investigations (Matin et al 2016; Matin and Chelgani 2016; Chelgani et al 2016a, 2016b; Shahbazi et al 2017; Chelgani and Matin 2018; Matin et al 2018; Nazari et al 2019; Tohry et al 2019; Jafari et al 2019a, 2019b), it is not yet widely used in mineral processing. Therefore, this worked used RF for ranking variables of a SLon® unit (rougher and cleaner stage) based on their effec on the separation efficiency (SE) for reprocessing IOTs in an industrial plant.…”

Special Issue: Bioprocess Monitoring and Control

“…Jafari et al [6] studied a bioleaching process for the extraction of metals from a flotation concentrate. In their contribution, results regarding the influence of two typical flotation frothers on the sensitivity of bacteria in the mesophilic mixed culture are presented.…”