Abstract. thorium can be precipitated as a salt of p-dimethylaminoazophenylarsonic acid at a pH of about 1.5. the precipitate, collected on a sintered glass filter is washed with dilute ammonium hydroxide to dissolve the dye. the amount of thorium is determined by measuring the concentration of the dye spectrophotometrically at a wavelength of 450 millimicrons. Zirconium, which interferes, can be separated and determined using the same reagent in strong hydrochloric. the behavior of thorium metal upon treatment with various acids and upon fusion withKHSO4 is described. three satisfactory procedures are given for dissolving the metal with sulfuric acid, phosphoric acid, and by a potassium hydrogen sulfate fusion. The laboratory was presented with the problem of analyzing for a large number of elements in O2 metal. the results of a systematic study of methods for effecting solution of the metal are offered here since they may be of some interest and use to other laboratories. The four methods which effected complete solution of the metal are (1) Sulfuric acid method; (2) Fusion method; (3) Phosphoric acid method; and (4) Nitric acid-hydrofluoric acid method.

Technical report. Numerous application of various column adsorption techniques to inorganic analytical chemistry have appear in the literature. The comparatively recent introduction of ion exchange resins has resulted in the development of efficient, simple, and rapid column adsorption methods. the principal service of column adsorption methods to analytical chemistry is that of providing a relatively simple means of separating an element in a sufficiently pure state so that a direct precipitation, ignition, and weighting, for example, will suffice to complete the quantitative analysis. Systems involving uranyl nitrate will naturally be emphasized in this report but information will be included concerning the separation of the individual members of a series from one another, such as in the alkaline earths and the rare earths.

.Technical report describing the transference experiments. The carrying of zirconium and columbium by ferric hydroxide has a very marked dependence on pH. In the experiments it was noticed that the concentration of Zr activity in various solutions changed with time This indicated that the Zr was being adsorbed on the glass. The carrier free trace is adsorbed on glass. This effect must be considered in experiments with Zr tracer in glass apparatus.

Abstract. A summary of the effect of metal, carbon, silicon, and oxygen impurities upon the various sulfide refractories is given and the proper procedures for elimination of the impurities are discussed. CeS which is properly prepared can be handled in air without danger of catching fire or appreciable oxidation. 650 satisfactory crucibles have been made to date using sulfides which were screened and pressed in air with less than 0.5% oxygen pickup. The other cerium and thorium sulfides are even more inert to oxidation than is CeS. Phase diagram possibilities are discussed for the cerium and thorium sulfide and oxy-sulfide systems. Further study of the ThS has shown that ThS crucibles are the highest melting and least volatile of the sulfide crucibles and ThS may be used for remelting of some metals up to 2000 degrees C. ThS crucibles appear to be the most suitable containers for metal reductions.