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The similarity of surface properties of dolomite and phosphate minerals leads to limited or no selectivity in their separation by flotation. Many chemical additives were tested; however, a limited success was achieved. Recently, bio-surfactants and bacteria have received much focus not only because of their environmentally friendly behaviour but also for their enhanced selectivity in different processes such as flotation. In this paper, the adsorption of Pseudomonas Aeruginosa (PA) bacteria onto francolite and dolomite was investigated. The adhesion of bacteria was studied by adsorption isotherm, zeta potential, and Fourier Transform Infra-Red (FTIR) spectroscopy to reveal the effect of bacteria on the floatability of each mineral. The proposed adsorption mechanism depends mainly on physical interaction due to Van der Waal's, bridging, electrostatic, as well as hydrophobic forces.

The amenability of carbonate separation from a sedimentary phosphate ore using a bioflotation process was studied. Two types of bacteria were chosen for this study. The experiments were performed using oleic acid as collector. The flotation experiments were carried out using statistical designs for optimizing the main operating parameters. A concentrate containing 0.78% MgO and 30.15% P2O5with a recovery of 92.31% was obtained from a feed containing about 2.45% MgO and 27% P2O5These specifications could not be obtained using conventional flotation experiments under similar conditions in the absence of bacteria. Measurements of zeta potential, adsorption of bacteria and collector, as well as froth power, were performed to explain the role of microorganisms in the surface modification of both dolomite and phosphate and in their interaction with the collector.

This paper reviews technologies used for the beneficiation of siliceous and calcareous phosphate ores of different origin. The review sheds light on recent trends suggested for solving problems associated with separation of different impurities from phosphates. Applications of recently modified flowsheets as well as new reagents in the flotation of phosphate ores of sedimentary origin are highlighted.

Dolomite is found to undergo preferential dissolution in aqueous solutions and this is found to be strongly dependent on the solid to liquid ratio (SIL). Electrokinetic studies done under the same conditions revealed that the mineral surface charge is also affected markedly by the solid content in the suspension. Conditioning of the dolomite at low SIL ratios for short time intervals showed preferential dissolution of calcium leading to a magnesium-enriched dolomite surface. At higher SIL ratios and longer conditioning times, calcium depletion from the solution and a calcium-enriched dolomite surface resulted. The results are discussed in terms of surface precipitation and/or bulk precipitation and surface conversion of dolomite to the calcium-enriched phase (calcium carbonate and/or magnesian calcites).

Serological studies of male accessory sex tissues, employing rabbit antiserum to rat vesiculo-prostate complex, have indicated a high degree of specificity for the accessory glands system. By gel diffusion methods, the accessory glands, i.e. seminal vesicle, coagulating gland, ventral and dorsolateral prostates, and Cowper's and preputial glands, have been found to contain common antigen(s), although some of the glands were shown to have individually specific antigens as well. A slowly diffusing antigen was highly characteristic of the vesiculo-prostate complex and was found consistently in seminal vesicle, coagulating gland and dorsolateral prostate, as well as bulbo-urethral gland and vas deferens. Testis, uterus and mammary gland, and non-genital tissues gave negative reactions with the tissue-specific antisera. A study of other species of vesiculo-prostate (human, monkey, guinea-pig, rabbit and mouse) showed that only the mouse contained cross-reacting antigen(s).By immunofluorescence, it was confirmed that rat accessory glands contained common antigen(s) and that the mouse contained cross-reacting antigen(s). The specific nature of the homologous reaction was confirmed by tanned cell haemagglutination.It is implicit in these findings that the highly tissue-specific, species-restricted antigens which characterize the accessory sex glands may be used to classify them and study their growth, function and evolution.