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In the roasting of sulphide minerals, the conventional roasting practices such as Herreschoff`s, Flash, Fluosolid roasting involve movement of solids during roasting, thus, considerable amount of dust production and increased conversion of SO₃ in the exhaust gas are unavoidable. This paper describes an improved method which overcome some drawbacks of the current processes. The ore fines are formed in a briquette with holes and roasting is carried out in a stationary manner. The findings from the tests using pyrrhotite are as follows: ① Proper green briquette can be obtained with ore fines of minus 140 mesh without any binder except 11.5% of water addition. ② Production of dust and sulphur trioxide in the exhaust gas can be lowered down to 0.18g/㎥ and 0.05% SO₃ content. ③ The cinder can be directly used for iron malting after dead roasting without further processing ④ The roasting is self sustaining and possibly applied to other sulphide minerals.

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The effects of Zr, Ca and Ce on the rate of first stage graphitization, nucleation and growth of graphite particles in nodular cast iron were studied. Activation energies of nucleation and growth were measured and their interrelation was discussed. The activation energies of nucleation and growth of graphite were ranged from 22,000 to 35,000 ㎈/㏖., from 25,000 to 35,000 ㎈/㏖, depending on the nodulizing elements, respectively. The effects on graphitization were as follows. ① The graphitization of Zr-treated cast iron was accelerated by both nucleation and growth of graphite. ② The graphitization of Ca-treated cast iron was accelerated by growth of graphite than nucleation of graphite. ③ The graphitization of Ce-treated cast iron was accelerated by nucleation of graphite than growth of graphite.

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Two experimental methods are used for the study of H₂-diffusion in polycrystalline zinc. Diffusion coefficients (D.C.) of hydrogen in Zn, which are first measured with the gasvolumetric method, are as follows: D=5.8×10^(-3) exp(1400±200/RT)㎠/sec in 99.99%Zn D=4.2×10^(-3) exp(2200±200/RT)㎠/sec in 99.9%Zn The above results are almost good conformed with theoretical one. D.C. of H₂-diffusion in 99.9% Zn are also measured at room temperature with the electrochemical method. But this value is smaller than that obtained from the gasvolumetric method. The reasons of discrepancy between the values obtained from the gasvolumetric method and from the electrochemical method are discussed. The solubility of H₂ in Zn calculated at 200℃ is about 5.3×10^(-3) cc(NTP)/100gr Zn.

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At the pretreatment of base surface and chemical plating of nickel on the surface of polystyrene there are various differency by solution composition and processing. However, the best range of PH in palladium chloride solution for sensitizing was 4.0∼4.5, and the treatment was completed with one minute at the room temperature. The effective composition ratio of solution was 3:1:1 of nickel chloride, sodium hypophosphite and sodium acetate respectively, its PH was 4, and adequate temperature was over 90℃.

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The materials of ship propeller are manganse bronze and aluminum bronze which have short freezing ranges, freeze by "skin formation" in a straightforward way and tend to form symmetrical pipes at the open heat centers. In this paper, the relations between various castings and risers by the molding design for determining the optimum size of riser were investigated when a fixed pitch propeller was marufactured. Two types of patterns were used, that is, metal and strickle sweep pattern. The optimum allowance of shrinkage are 15/1000 in the case of manganse bronze and 20/1000 in the case of aluminum bronze. The size of sprues and runners which have some skin bob were determined by pouring weigh, and insulating riser sleeve was used for the riser. As the result, the pouring weight can be determined by the weight of propeller, and the diameter and height of riser which have a core in the center can be determined by the diameter and height of boss in propeller for manganse bronze and aluminum bronze castings.

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Fabrication variables of sintered aluminum solid capacitors were studied in relation to their electrical properties. The porosity of anode pellets was controlled by varying the content of binder and compacting pressure. The dielectric oxide layer on the porous surface of sintered anode pellets was formed by anodizing in 3% ammonium borate aqueous solution. The solid electrolyte on the dielectric oxide layer was applied by pyrolysis of manganese nitrate. Pyrolysis and reformation at a reduced voltage were repeated a few times. Electrical properties of sintered aluminum solid capacitors so fabricated were superior to those of aluminum electrolytic capacitors whereas they were inferior to those of sintered tantalum solid capacitors. A capacitance-voltage product of 2.450 μF·V/gram was achieved but a sufficiently low leakage current was not achieved as yet. This fact may be attributable to low sintering temperature and consequently, relatively high contents of impurity remaining in sintered anode pellets.

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Crude Zinc metal was electrorefined using electrolytic cell which consists of two compartments separated by a barrier that is immersed in a shallow pool of zinc amalgam without reaching the cell bottom. The amalgam, agitated with stirrer, acts as a cathode on one side and an anode on the other side. ZnSO₄ solution buffered with acetate was used as the refining solution. The current efficiency was 99.0% at pH 4.5. The electrorefining by using 99% Zn resulted in obtaining>5-9s.

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In the electrode position on the vertical plate cathode immersed in an unstirred electrolyte, a concentration boundary film is formed along the cathode surface and the cathodic limiting current density is determined by the transfer rate of copper ion through the film. Moreover, the decrease of copper ion concentration in this film causes an upward natural convective flow of electrolyte along the surface and the average cathodic limiting current density is expressed by equation (6). The effects of copper ion concentration in the bulk electrolyte and of the height of the cathode on the cathodic limiting current density can be interpreted by this equation. The natural convective flow becomes turbulent when the Reynolds number concerning the film thickness exceeds 200 and the experimental results were summarized by an equation composed of dimensionless numbers of Sh, Sc and Gr. The apparent activation energy of diffusion of copper ion in the electrolyte was estimated at 4.8 ㎉/㏖.

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