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Abstract: The distribution of frother reporting to the concentrate along a bank of cells and the adsorption of collector to valuable particles are important as they determine the froth structure and flotation performance. An understanding of this is required in order to formulate better reagent addition strategies. Techniques to measure the frother concentration in samples taken from industrial flotation circuits, including dynamic surface tension measurements, have proven inconclusive due to the low concentrations used and the effects of hydrophobic particles. In this study, a method of measuring the concentration of non-adsorbed reagents on a laboratory scale has been developed. Batch flotation experiments were carried out on an industrial sulphide ore. The adsorption of the collector (SIBX) and frother (Dowfroth 200) to the solid particles was determined by measuring the concentration remaining in filtered liquid samples taken from the concentrate and tails. Analysis was carried out using UV spectrometry and TOC analysis. It was found that 20% of the frother is lost in the presence of the SIBX and that after 2min, 63% of the SIBX had adsorbed to particles. The results also showed that an increase in the initial concentration of SIBX, and an increase in the conditioning time yielded a higher concentrate grade. [Copyright &y& Elsevier]

The recovery and grade of concentrates obtained by flotation is partly dependent upon froth structure. The flotation froth structure can be modified, and hence the flotation performance modified, by the addition of reagents.A direct control system was developed which permitted pre-determined addition profiles of reagent and water to be added to a cell. A series of experiments were performed using different strategies of reagent (Triton x-405) addition for the flotation of Bickershaw coal.A transputer enhanced Micro-Vax Computer was employed to grab images of flotation froths and to process them quantitatively in a parallel procedure. Using image processing techniques characterization of froth structures was achieved. The image processing procedures that were intended to run on-line, were examined and developed using video tapes of experimental runs, off-line.An essential stage in the development of such a system is the understanding of the adsorption behaviour of the reagent in terms of the kinetics, the distribution of reagent between the solid and solution phases, and the resulting effect on the froth structure. A kinetic model was developed to describe the adsorption of the reagent on the particles. The experimental recoveries and froth structure were investigated in terms of reagent distribution and the froth structure. [Copyright &y& Elsevier]

The article reports a carbapenem-resistant isolate of Klebsiella pneumoniae that was found to be positive for metallo-β-lactamase (MBL) production. A K. pneumoniae strain was isolated from blood culture of a Turkish child with neuroblastoma. Etes results show that the strain was resistant to imipenem, meropenem, cefotaxime, ceftazidime, ceftriaxone, piperacillin-taxobactam, cefoperazone-sublactam and amikacin, but susceptible to gentamicin and ciprofloxacin.