Yazar "Ozkan, Alper" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • Küçük Resim Yok
    Öğe
    Comparison of stages in oil agglomeration process of quartz with sodium oleate in the presence of Ca(II) and Mg(II) ions
    (ACADEMIC PRESS INC ELSEVIER SCIENCE, 2009) Ozkan, Alper; Ucbeyiay, Hawanur; Duzyol, Selma
    The oil agglomeration of quartz with sodium oleate in the presence of calcium and magnesium ions comprises three consecutive stages: adsorption of cations onto quartz surfaces, which leads to coagulation of the Suspension, shear flocculation with sodium oleate and finally, agglomeration of flocs by kerosene. The effects of pH and cation concentration on these stages were investigated and the results were presented comparatively. It was found that all the stages of oil agglomeration of quartz exhibited sharp dependences on pH and cation concentration. That is, these stages generally took place in the pH and concentration ranges in which hydroxy complexes of the cations existed in the Suspension. In the case of magnesium ion, the coagulation, shear flocculation and especially oil agglomeration of quartz improved after precipitation of hydroxide. These species of calcium and magnesium ions formed at high pH were adsorbed oil the negatively charged Surface of quartz, as a result Of which the adsorption of sodium oleate became possible and thus the shear floccuation of the particles was achieved. Thereafter, the hydrophobic quartz flocs could be agglomerated by kerosene as bridging liquid. The increase in the shear flocculation efficiency depending oil the increase of surface hydrophobicity enhanced the oil agglomeration of quartz with kerosene. The maximum recoveries for all the stages of the quartz were obtained in the presence of 10(-3) M magnesium and 5 x 10(-3) M calcium ions at pH 11. However, some differences in file behavior of shear flocculation and oil agglomeration of quartz suspension were observed above 10(-3) M concentration of magnesium ion. (C) 2008 Elsevier Inc. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Correlations of Bond and Breakage Parameters of Some Ores with the Corresponding Point Load Index
    (WILEY-V C H VERLAG GMBH, 2012) Aras, Ali; Ozkan, Alper; Aydogan, Salih
    This paper presents significant correlations of the Bond parameter (work index, Wi and grindability, G) and the breakage parameters (specific rate of breakage, Si and the fineness value, ?) with the point load index (Is(50)). The experimental results obtained from calcite, barite, colemanite and bauxite samples have demonstrated that the Bond and breakage parameters were closely correlated with the point load index. That is, the values of G, Si and aT parameters decreased with the increase in the values of the point load index; however, the ? parameter of Bi,j increased with increasing Is(50) values.
  • Küçük Resim Yok
    Öğe
    Effects of Some Multivalent Ions on Coagulation and Electrokinetic Behaviours of Colemanite Particles
    (CSIRO PUBLISHING, 2013) Ucbeyiay, Havvanur; Ozkan, Alper
    The effects of magnesium, barium, aluminium, and ferric cations as multivalent ions on the coagulation and electrokinetic behaviours of colemanite have been investigated in relation to pH and cation concentration. The zero point of charge for colemanite was determined to be at pH 10.2. The positive surface charge of colemanite increased in the presence of multivalent ions at pH values below the zero point of charge. Also, these ions changed the zeta potential of colemanite from negative to positive within the pH range 10.2 to 12. In the experiments, the coagulation of colemanite with ferric ions was more efficient than with the other ions and the effect of ferric ions varied considerably depending on the concentration and pH. The coagulation recovery values of colemanite suspension increased quickly up to 2.5 x 10(-3) M concentration of ferric ions and the maximum value (similar to 93 %) was obtained at a pH of 11.5. It was also found that the coagulation behaviour of the colemanite suspension in the presence of multivalent cations was in good agreement with the electrokinetic characteristics.
  • Küçük Resim Yok
    Öğe
    SELECTIVE SHEAR FLOCCULATION OF CELESTITE WITH AERO 845
    (INT SCIENTIFIC CONFERENCE SGEM, 2008) Ucbeyiay, Havvanur; Ozkan, Alper
    In this study, selective shear flocculation of celestite with Aero 845 as anionic surfactant from the mixtures of celestite and calcite was investigated using sodium silicate, sodium phosphate and sodium polyphosphate as inorganic dispersants. The effects of pH and dispersant concentration on the selective flocculation of celestite mineral were studied. Experiments carried out with sodium silicate at optimum conditions yielded a concentrate, which is flocculated material, assaying 82.5% SrSO(4) with a recovery 79% and separation index of 0.62 front a mixture containing 50% SrSO(4).
  • Küçük Resim Yok
    Öğe
    A STUDY ON SHEAR FLOCCULATION OF MAGNESITE SUSPENSIONS
    (INT SCIENTIFIC CONFERENCE SGEM, 2008) Duzyol, Selma; Ozkan, Alper
    Shear flocculation characteristics of magnesite with sodium oleate as anionic surfactant have been investigated in this study. The effects of various parameters such as pH, stirring speed and concentration of sodium oleate on the shear flocculation of magnesite were determined. It was found that the shear flocculation of magnesite was not affected much by the pH changes of the suspension. However, the flocculation of magnesite showed strong dependences on stirring speed and surfactant concentration. By evaluation of the experimental results, optimum conditions for shear flocculation of magnesite were determined as: pH, alkaline levels; sodium oleate concentration, 20 mg/dm(3) and stirring speed, 500 rpm. Under these optimum conditions, magnesite fines in the suspension could be flocculated with a recovery of 84%.