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Metallurgical evaluation of copper ore flotation performance in the presence of Rhamnolipid biosurfactant produced from Pseudomonas aeruginosa. Part 1: Copper-bearing minerals

Biniaz Gholamreza, Khoshdast Hamid, Garmsiri Mohammad Reza, Maleki-Moghaddam Mostafa, Hassanzadeh Ahmad

Physicochemical Problems of Mineral Processing

2023

Vol. 59, iss. 5

art. no. 183176

The present research work studies the effect of rhamnolipid biosurfactant (RL) produced from Pseudomonas aeruginosa bacteria on the metallurgical response of a copper ore sample flotation through an extensive full factorial experimental design. Key influential factors including feed particle size, pulp solid content, pH, and dosages of collector, frother and RL biosurfactant were considered. The surface activity of the RL biosurfactant was also studied based on a D-optimal experimental design. Surface activity results revealed that increasing pH and electrolyte concentrations negatively impacted the RL surface activity, while the effect of electrolyte source was dependent on their ionic strength. Metallurgical investigations showed that operating parameters significantly influence the copper grade and recovery with considerable interaction among various parameters. RL biosurfactant was found to negatively decrease the copper grade (~0.5%) and positively enhance the recovery (~3%). Effect of RL was attributed to two potential mechanisms, i.e., being ineffective on copper minerals and/or interaction with gangue minerals, as well as increasing the rate of entrainment due to high foamability, both of which increased non-selective recovery of gangue minerals. Interestingly, regardless of the structural similarities, no interaction between the flotation reagents and rhamnolipid was observed. Fourier-transform infrared (FTIR) spectroscopic analysis of copper minerals, both pure and RL-exposed, showed that there was actually no molecular interaction between RL molecules and particle surface.

Efficient chromium removal from aqueous solutions by precipitate flotation using rhamnolipid biosurfactants

Shojaei V., Khoshdast H.

Physicochemical Problems of Mineral Processing

2018

Vol. 54, iss. 3

1014--1025

In the present research study, the efficient removal of hexavalent chromium from aqueous solutions by precipitate flotation method was investigated. The experiments were carried out with the use of ferrous sulfate as a precipitating agent for chromium and rhamnolipid bio surfactant (RL) as a precipitate collector. The effects of rhamnolipid and co-precipitate concentrations, aeration rate, solution pH, and salt addition on the chromium removal were studied using a full factorial design. The chromium removal and water recovery to foam products were analyzed as process responses. Statistical analyses showed that the effects of all factors on the chromium removal followed a non-linear trend with a peak at the middle level. After the process optimization, the maximum chromium removal of 96.75±0.3% was obtained at pH value of 8, RL/Cr ratio of 0.01, Fe/Cr ratio of 3, and aeration rate of 50 cm3/min. Addition of salt with different cationic and anionic groups negatively influenced the removal efficiency. Kinetic studies suggested that the process of chromium removal by the precipitate flotation followed the first-order process with a rate constant of about 0.018 sec-1. Given the good removal capacity and kinetics, rhamnolipid biosurfactants can be a promising environmental-friendly bio collector for the removal of chromium ions from aqueous solutions.