Dephosphorization Ability Estimation of FetO-Rich Demanganization Slag during Hot Metal Pre-Treatment

In order to find out the optimum thermodynamic conditions for hot metal dephosphorization and predict phosphorus content after demanganization pretreatment, thermodynamic equilibrium experiments between CaO-FetO-SiO2-MnO-P2O5 slag and silver/solid iron were carried out in an iron crucible at different temperature under pure argon atmosphere in an electric resistant furnace. The results indicate that phosphorus distribution ratios increase with an increase of basicity in the slag at the experiment temperature, and then they decrease with an increase of basicity at 1573K and 1623K. The phosphorus distribution ratios decrease with an increase of FetO content in the slag at 1573K, while they increase with an increase of FetO content in the slag and then decrease with an increase of FetO content in the slag at 1623K. The results indicate that the maximum phosphorus distribution ratio between slag and hot metal is 92.4 when basicity of the slag is 1.7 and FetO content in slag is 49.75 mass% at 1623K, and the correspondent phosphorus content in the carbon saturated iron is 0.019mass%. Dephosphorization is easier under low temperature. The equilibrium quotient of phosphorus obtained in the present work is formulated as a function of slag compositions and temperature using the multiple regression method which is used to predict phosphorus content equilibrium with the demanganization slag and optimum conditions needed for ideal phosphorus contents in demanganization pretreatment.

Spectrophotometric Study of Adduct Formation Between [Co(Salen)PPh3]ClO4.H2O and [Co(7,7'-Dimethylsalen)PPh3]ClO4.H2O with Amines Donors in Acetonitrile

The equilibrium quotient of the adduct formation of [Co(Salen)PPh3]ClO4.H2O and [Co(7,7'-dimethylSalen)PPh3]ClO4.H2O, as acceptor with amines donors are studied by spectrophotometer. Thermodynamics of these pentacoordinate cobalt(III) Schiff-base complexes have been examined withn-butylamine,sec-butylamine,tert-butylamine, benzylamine and diethylamine in constant ionic strength of 0.1 M sodium perchlorate and acetonitrile solvent at room temperature. We aimed to investigate the effects of different electronic and steric situations of donor and acceptor by comparing their equilibrium quotient for any adduct.

Aluminum(III) Coordination to Hydroxy Carboxylates: the Influence of Hydroxy Substituents Enabling Tridentate Binding

Potentiometric evalution of the interaction between aluminium(III) and the hydroxy carboxylates 3-deoxy-D-ribo-hexonate (L1H) and 2,5-dihydroxypentanoate (L2H) provided evidence for the formation of 1:1 complexes only, though with the ligand being present in singly, doubly and quadruply deprotonated forms in the hexonate complexes, and in singly, doubly and triply deprotonated forms in those of the pentanoate. At 298 K in aqueous media, I = 0.1 ( NaCl ), equilibrium quotient values obtained through use of the programs PKAS and BEST were: -log([(L1)-][H+]/[L1H])(or pKa(L1H))= 3.58�0.03 log([(AlL1)2+]/[Al3+][(L1)-])=1.97�0.03 log([(AlH-1L1)+][H+]/[(AlL1)2+])= -2.83�0.05 log([(AlH-3L1)-][H+]2/[(AlH-1L1)+])= -9.17�0.08 -log([(L2)-][H+]/[L2H])(or pKa(L2H))= 3.92�0.03 log([(AlL2)2+]/[Al3+][(L2)-])= 2.04�0.03 log([(AlH-1L2)+][H+]/[AlL2)2+])= -3.14�0.06 log([AlH-2L2][H+]/[(AlH-1L2)+])= -2.25�0.09 The very close similarity of the results for 3-deoxy-D-ribo-hexonate (3-deoxygluconate) and those known for D(+)-gluconate has led to the suggestion that the complexes of the quadruply deprotonated ligands may involve trialkoxo coordination through the C1, C5 and C6 substituents.

CHELATION STUDY OF COPPER (II): FULVIC ACID SYSTEM

The chelation reaction between Cu (II) and fulvic acid has been investigated using a relatively new direct approach — that of titration with a cupric ion-selective electrode. The results of different investigators are in fair agreement with each other if they are interpreted in terms of both pH and mole fraction of reactants. In 0.1 M sodium nitrate solutions with a copper mole fraction equal to 0.5 ± 0.2, the equilibrium quotient at 25 C and pH 3 was found to be 2.2 ± 0.1.

Evaluation of Unbonded O—H Groups for HDO in Liquid D2O from Infrared Absorptivity Measurements

Wyss and Falk's infrared absorptivities between 10 and 85 °C for HDO in liquid D2O in the fundamental O—H stretch region have been analyzed numerically and show a statistically significant weak band near 3600 cm−1 at each temperature. This band, the Raman analog of which was reported earlier, confirms the presence of HDO species with unbonded O—H groups in the liquid state. The percentage of HDO species with un-bonded O—H groups is found to be 4.6, 6.1, 10.1, and 11.9, respectively, at 10, 35, 60, and 85 °C.The four predominant HDO species in equilibrium at low temperatures are denned together with their equilibrium constant for the [Formula: see text] bond-rupturing process. A standard enthalpy change of ΔH° = 6800 ± 1100 cal is found for the rupture of one mole of [Formula: see text] bonds. This is in contrast with the apparent enthalpy change of 2900 ± 500 cal, as usually derived from the temperature dependence of the equilibrium quotient. Approximate mole fractions for each of twelve differently bonded HDO species are derived from a model for random H- and D-bond statistics. Results show that the four predominant HDO species give a full interpretation of the absorptivities at 10, 35, and 60 °C but that additional minor species contribute slightly to the absorptivity at 85 °C.

LINEAR FREE ENERGY RELATIONSHIPS CONCERNING EQUILIBRIA IN MODERATELY CONCENTRATED MINERAL ACIDS: A SIMPLE METHOD FOR ESTIMATING pK's OF WEAK BASES

Linear relationships exist between the logarithms of equilibrium quotients, [SH+]/[S][H+], of diverse bases as they vary with acid concentration in moderately concentrated mineral acids. For purposes of formulating these linear free energy relationships in standard form, the equilibrium quotient for protonation of a hypothetical aromatic primary amine of pKa zero has been chosen as horizontal coordinate; this is given by (−H0 − log [H+]). Log ([SH+]/[S]) + H0 is plotted against (H0 + log [H+]). The slope, [Formula: see text] of the linear plot is a parameter which characterizes the response of the equilibrium quotient to changing acid concentration. The intercept represents the thermodynamic pKa of the base. This constitutes a general method for estimating the pKa of any base which undergoes protonation in moderately concentrated mineral acid, with reference to the single acidity function, H0. For bases of diverse type, pK's estimated by this method are in good agreement with those estimated by the acidity function method. Use of the new correlation procedure as a check on the validity of several acidity functions and its application to equilibria not involving proton gain or loss are also discussed.