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    EFFECT OF SODIUM, CALCIUM, MAGNESIUM, AND CHLORIDE-IONS ON THE SOLVENT-EXTRACTION OF BORON FROM AQUEOUS-SOLUTIONS
    (Marcel Dekker Inc, 1995) KAHRAMAN, F
    The effect of Na+, Ca2+, Mg2+ and Cl- ions upon the solvent extraction of boron from aqueous solutions has been studied. The extraction of Na+, Ca2+, Mg2+ and Cl- ions singly and in various mixtures into 2-ethyl-1,3-hexanediol(EHD), 2-chloro-4-(1,1,3,3-tetramethylbutyl)-6-methylolphenol (CTMP) and 1:1 mixture of the two is considered here. The results show that in the absence of berates each of the solvent systems will extract a small amount of dissolved Na+, Mg2+ and Ca2+ cations, presumably as solvated ion pairs, and the order of extraction is generally CTMP > CTMP/EHD > EHD and Ca2+ > Mg2+ > Na+ (all exhibiting considerable increase with pH). A maximum is achieved for calcium with CTMP at pH 11. These observations are consistent with larger bulk shielding effect of CTMP in ion-pair formation and also with its (likely) stronger acidity. The same general trends are observable in the extraction of the same cations in the presence of boron, but the effects are much greater. However, the extent of the extraction of boron is little affected by the presence of the cations. These results can be rationalized if it is assumed that any of the species H+, Na2+, Mg2+, or Ca2+ can act as counter ions in the formation and extraction of borate-cation complex ion pairs.
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    INVESTIGATION OF SOLVENT LOSSES IN THE SOLVENT-EXTRACTION OF BORON
    (Marcel Dekker Inc, 1995) KAHRAMAN, F
    Solubility, adsorption onto mineral particles and entrainment of 2-chloro-4-(1,1,3,3-tetramethyl-butyl)-6 methylol-phenol (CTMP) in aqueous slurry phase are considered here. The results show that, the solubility at equilibrium increased sharply with pH, but remained at only 16 parts per million (ppm) at pH 9. With regard to adsorption onto various mineral phases considered, the affinity for CTMP increases in the order quartz < clay minerals < carbonates. The adsorption is about 9 and 13 ppm for quartz and bentonite respectively. The entrainment at pH 9.2 is about 107 and 110 gm(-3) for bentonite and the Kirka slurry respectively.
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    Öğe
    SOLVENT-IN-PULP EXTRACTION OF BORON FROM SLURRIES
    (Marcel Dekker Inc, 1995) KAHRAMAN, F
    Solvent-in-pulp extraction of boron from various slurries has been studied. Extraction of boron from synthetic slurries of quartz, bentonite and from natural plant-end-slurry from Kirka/Turkey with 2-ethyl-1,3-hexanediol (EHD), 2-cloro-4-(1,1,3,3-tetramethyl-butyl)-6-methylol-phenol (CTMP) and 1:1 mixture of the two is considered here. The results show that, under the pulse conditions used, phase separation appeared acceptably sharp and the level of clarity is acceptable regardless of pH. The transmittance evidently decreased with increase in pH but did not drop below about 75%. However, some solid and water were transferred and the organic layers were slightly turbid in decreasing order CTMP>CTMP/EHD>EHD but the phase clarity is reduced by solids in the order quartz>bentonite>water. Combining the data of observed turbidities on extraction with the transmittance measurements of the organic phase rough estimates of solids transferred may be made, For example, in the case of extraction from bentonite slurry at pH 9 the % solids in the organic phase are 0.4, 0.3 and 0.1 for CTMP, CTMP/EHD and EHD respectively, assuming that the solids content of the aqueous phase is 50, 000 gm(-3). Values are of course lower at lower pH. For quartz slurries the corresponding figures are; 0.3, 0.2 and 0.05.