Solubility of BaS in BaO-BaF2 slag and the Influence of FeOx,SiO2, Cr2O3, BaCI2, CaO,and MgO on the sulfide capacity of this system

The influence of SiO₂, FeO_x, Cr₂O₃, BaCl₂, CaO, and MgO on the sulfide capacity of the BaO-BaF₂ system was measured at 1473 K, using a gas-slag-metal equilibration technique. It was found that the substitution of BaF₂ by SiO₂, FeO_x, Cr₂O₃, and BaCl₂ decreases the sulfide capacity of the BaO-BaF₂ system. Similar results were obtained for the carbonate capacity. The CaO-saturated BaO-BaF₂ flux, however, was found to have slightly higher sulfide and carbonate capacities than the pure BaO-BaF₂ flux. The solubility of CaO increased with increasing BaF₂ content and was 18 mol pet in BaF₂ at 1473 K. The solubility of MgO in the BaO-BaF₂ system at the same temperature is very low, and it has no effect on the sulfide and carbonate capacities. The solubility of BaS in the BaO-BaF₂ system was also measured at 1473 K and had its maximum for the slag containing 40 mass pet BaO. The activity of BaO in the system was calculated from those data. IVAN P. RACHEV, formerly Graduate Student, Department of Metallurgy, The University of Tokyo.     

Solubility of platinum in molten fluxes as a measure of basicity

The solubility of platinum in the molten BaO-Al₂O₃, BaO-SiO₂, CaO-Al₂O₃, CaO-SiO₂, Na₂O-SiO₂, and CaO-Al₂O₃-SiO₂ systems has been measured in order to seek a new measure of basicity. The solubility of platinum increases with increasing content of basic oxide. The correlations among the solubility of platinum, carbonate, sulfide, and phosphate capacities, basic oxide activities, and theoretical optical basicity are discussed.     

Diagnosis and treatment of tumours in the pineal region

In a series of 3.072 cases of intracranial neoplasms up to the end of 1973 there were 82 tumours in the pineal region (2.7%), excluding meningiomas of the falx and tentorium. More than half (forty seven) were pinealomas (two cell pattern type tumours, and pineoblastomas), twelve were teratomas, eight were ependymomas, three were epidermoids, and the remainder were gliomas. In addition to ventriculography, millipore filter-cell culture of cerebrospinal fluid, and fibre ventriculoscopy were found useful for diagnosis. Most of the patients were treated by surgery followed by radiotherapy. Results with the pinealomas were fairly good, the one year, five year, and ten year survival rates being 87.5%, 71.4%, and 33.3% in those below the age of 15 years, and 80.0%, 46.2%, and 12.5% in those above that age. The radiosensitivity of pinealomas and the beneficial effect of reduction of tumour bulk by direct surgery may both be important factors in the achievement of good results.     

Thermodynamics of lead and bismuth in CaO–CaF2 melts

In order to understand a new refining process for removing tramp elements from alloy steels under strongly reducing conditions, the authors previously reported the thermodynamic behaviour of P, Sn, Sb, As and Cu in CaO–CaF₂ melts. In this investigation, the thermodynamic behaviour of Pb and Bi in CaO–CaF₂ melts under oxygen partial pressures from 10^?16 to 10^?20 atm was studied at temperatures ranging from 1360 to 1550°C, using a similar technique. It was shown that Pb and Bi exist in slag mainly as Ca₂Pb and Ca_1.5Bi, respectively, under very low oxygen partial pressure although a part of Pb is soluble in slags as metal. The obtained results were extrapolated to lower oxygen partial pressures to investigate the possibility of removing these tramp elements from molten iron, causing Bi to be removed from molten iron below an oxygen partial pressure of 10^?23 atm, whereas Pb is removed under higher oxygen partial pressures.     

Simple optical wavelength meter in 700?1200 nm wavelength region

A new type of portable optical wavelength meter using a quartz rotator has been developed, designed for fibre optic transmission systems. The peak wavelengths of both lasers and l.e.d.s in the 700?1200 nm wavelength region can be measured. The measurement error was within ±1 nm at wavelengths around 850 nm.