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    Effect of nonionic and ionic surfactants on zeta potential and dispersion properties of carbon black powders
    (Elsevier, 2009) Sis, H.; Birinci, M.
    Dispersion of carbon black powders in aqueous medium was investigated by using anionic surfactant sodium oleate and a series of nonionic surfactants which were selected systematically to represent varying degrees of ethoxylation. Single and binary mixtures of the nonionic and ionic surfactants were employed in zeta potential and particle size measurements and a high affinity of surfactants on carbon black powders was beheld as they significantly changed the zeta potential and size distribution of the powders. But, noticeable differences between the surfactants were also observed, for example, as the nonionic surfactants reduced the absolute magnitude of zeta potential of powders in a wide pH range of 3.0-11.0, Na oleate made the zeta potential of the powders more negative under similar experimental conditions. The carbon black suspensions were agitated in a vessel having a standard geometry and the particle size measurements wet e carried out at desired time intervals without disturbance of the suspensions and interruption of agitation. Effect of surfactants on stability and dispersion of the powders were recognized with the reduction in mean particle sizes, as, in the absence of surfactant, the inean particle size could not be reduced below 24.0 mu m even after 210 min of stirring, it could be reduced to 5.35 mu m after 120 min of stirring in the presence of only 30 g/L of nonionic surfactant. Generally, it Was found that nonionic surfactants could wet and stabilize carbon black powders in aqueous medium better than anionic surfactant. The reason was explained by molecular structure and bulk properties of surfactants. (C) 2009 Elsevier B.V. All rights reserved.
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    Farklı Materyallerden Yapılmış Tabana Sahip Ahşap Kovanlarla Kışlatmanın Arılı Çerçeve Sayısı ve Kovan Ağırlığına Etkisi
    (2021) Birinci, M.
    Abstract:In this study, enrichment possibility of apatite-bearing iron ore sample was investigated to obtain iron and phosphate concentrate, separately. It was determined that the raw ore contains 35.75% Fe and 5.36 P2O5. Magnetite in the ore can be enriched with low-intensity magnetic separator, and apatite can be enriched from the non-magnetic product by flotation. For this purpose, the raw ore was ground below 106 m size and then subjected to magnetic separation (with two cleaner and one scavenger), and following flotation (with three cleaner and one scavenger). According to the experimental result, a magnetic concentrate containing 63.55% Fe and 1.65% P2O5, and phosphate concentrate containing 25.33% P2O5 and 6.45%Fe were obtained. The results show that there are still difficulties to obtain plausible iron and phosphate concentrates in terms of phosphorus and iron impurities for iron and phosphate concentrate, respectively. It is concluded that it is hard to separate the iron and phosphorus phases from each other, possibly due to complex mineralogical composition and poor mineral liberation of the ore.