Relative floatability as a criterion for evaluating the separation performance of phosphate from iron

This work was aimed to study the relative floatability of phosphate flotation by means of kinetic analysis.The relative floatability is important to determine how selectively the phosphate is separated from its impurities. The effects of pulp pH, solid content, reagents dosage(depressant, collector and co-collector) and conditioning time were investigated on the ratio of the modified rate constant of phosphate to the modified rate constant of iron(relative floatability). The results showed that a large dosage of depressant associated with a low value of collector resulted in a better relative floatability. Increasing the co-collector dosage, conditioning time and pH increased the relative floatability up to a certain value and thereafter resulted in diminishing the relative floatability. Meanwhile, the results indicated that increment of solid concentration increased the relative floatability in range investigated. It was also found that that maximum relative floatability(16.05) could be obtained in pulp pH, 9.32, solid percentage, 30,depressant dosage, 440 g/t, collector dosage, 560 g/t, co-collector dosage, 84.63 g/t and conditioning time,9.43 min.

Optical Properties of WO3-PbO Tellurite Glasses Doped with Rare Earths

The tellurium-based glasses TeO2, 85TeOz-15WO3, 85TeO2-10WO3-5Sm203, 77TeO2-20WO3-3Y203, 77TeO2-20WO3-3La203, 65TeO2-33WO3-2Er203 and 49TeO2-29.4WO3-19.6PbO-2Er203 have been prepared by melt quenching technique. Density and molar volume have been measured for the present glasses. Optical absorption studies are carried out on the glass system in the wavelength range of 200-900 nm. The compositions depend on different physical parameters such as density, molar volume and oxygen packing density will be discussed. Also, molar refraction （RM）, calculated refractive index （n）, metallization criterion （M）, electronic polarizability of the oxide ion （to2＂（Eopt） and optical basicity A^opt have been determined.

Effect of Ce_2O_3 on the 1.53 μm spectroscopic properties in Er^(3+)-doped tellurite glasses

Er3＋/Ce3＋ co-doped tellurite-based glasses with composition of TeO2-ZnO-Na2O are prepared by high- temperature melt-quenching technique. Effects of Ce2O3 content on the 1.53 μm band fluorescence spectra and fluorescence lifetime of Er3＋ are measured and investigated. It is found that the tellurite glass containing Ce203 with molar concentration of 0.25% exhibits an increment of 13% in 1.53 μm fluorescence intensity and an increment of 15% in the 4I13/2 level lifetime. The results indicate that the prepared tellurite-based glass with a suitable Er3＋/Ce3＋ codoping concentration is an excellent gain medium applied for broadband Er3＋-doped fiber amplifier （EDFA） pumped with a 980 nm laser diode.