In 1975, Sumitomo Metal Mining Co., Ltd. made a significant success on the foundation of a new plant for nickel and cobalt recovery from their sulfide mixtures and cobalt' hydroxide precipitate supplied by Marinduque Mining Co., Ltd. of Philippine and Sumitomo's conventional nickel refinery respectively by means of most advanced hydrometallurgical techniques including solvent extraction.
The Sumitomo's fully hydrometallurgical process developed for nickel and cobalt recovery covers the following technical features:
1) Nickel and cobalt separation by company's own solvent extraction technique
2) Production of electrolytic nickel and cobalt plate from their chloride solutions by electrowinning
3) Recovery of chlorine gas generated in electrowinning process followed by hydrochloric acid production
4) Gypsum production and ammonia recovery from ammonium sulfate solution ejected in solvent extraction process
Since the operations on commercial scale have been commenced in September of 1975, company has made great efforts to improve the process. And at present time, a new plant is in a position to provide electrolytic nickel of maximum 2, 500 t/Y and electrolytic cobalt of maximum 1, 500 t/Y, as well as some amount of their by-products such as nickel chloride, cobalt oxide, cobalt nitrate and so on without any major trouble.

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A substantial amount of energy have been saved by operating the blast furnace gas (LCV) burning power plant firstly built among the twelve ISP Smelters in the world.
Major characteristics of the power plant are summarized as:
1. Special firing technique for the LCV (low calorific value) gas in the boiler featuring:
1) A newly designed burner which enables the LCV gas of poor combustibility to burn both stably and continuously.
2) An oil burning pilot burner with a high turn-down ratio.
2. Pressure control technique for the LCV gas main to prevent the blast furnace and the boiler from undesireble pressure hunting.
3. An immediate turning-up technique for an oil burner in the case of emergency cut-off of a commercial line to supply sufficient power to an emergency line.
4. Supplemental firing of the oil burner to supply necessary amount of power and steam when the LCV gas volume sent to the power plant is insufficient.
5. An automatic by-passing procedure for process steam production in the case of turbine-trip.
6. Efficient anti-pollution measure (SOx and NOx reduction in the exit stack).
1) Mixed combustion of A and C grade oil. 2) Two step gas recirculation for NOx reduction. One- year operation of the plant has given the following results:
1. Power generated (average): 2000 kwh/h (20% of total demand of the smelter) Steam extracted: 5t/h
2. Effective prevention of pollution and any damage in the smelter to probably' be occurred in an emergency power stoppage.

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In many cases, rocks are composed of many crystal grains, and the stress distribution under uniform external force is not homogeneous but rather heterogeneous. This heterogenity is caused by the difference of elastic constants of each crystal grain. On the other hand, to measure the elastic constants of crystalline aggregate as a whole, it is necessary to eliminate the influence of individual grain properties. Therefore, the length of the strain gage must be considered carefullyf or the measurement. In this study, elastic constants of marble are measured, varying the gage length, and then, FEM analyses of uniaxial compression of marble composed of calcite are carried out. The results are follows;
1. Tensile stress greater than or equal to the 0.5 times as large as the axial compression stress is induced in the cross sectional plane of the specimen.
2. This tensile stress may elongate pre-existing cracks or nucleate new cracks.
3. To measure the elastic constants of crystalline rock specimen, the volume of specimen must be greater than 500 times grain volume.
4. The length of strain gage must be longer than 10 times apparent grain size.

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The present investigation was undertaken in order to make clear the adsorption property of α-terpineol and cineol onto the mineral surface and to clarify these influences on the floatability of mineral particles surface-chemically.
The gas chromatographic method was successfully used to analyze the concentration of a frother in the solution to determine the adsorption of α-terpineol and cineol on galena surface. The wettability of galena to frother was determined by capillary penetration tests. The floatability of galena was measured with a bubble pick up tube.
The adsorption density of frother molecules on galena increased with increasing the concentration of a frother in the solution. The adsorption quantities of cineol on galena were larger than those of a-terpineol in either case with or without xanthate addition in the solution. The critical flotation curves of galena were determined when xanthate was used alone and also was used together with one of the frothers. The floatability of galena with xanthate increased greatly in the presence of frother, and decreased in the following order: cineol+ xanthate>α-terpineol+xanthate>xanthate.
From these results, it was confirmed that the adsorption property of frother molecules onto the mineral related closely with the floatability of mineral and consequently the frother adsorption should play an important role in flotation.

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Deposits were obtained on the platinum cathode from the perrhenate solution under potentiostatic conditions and electroreduction process of perrhenate ion was studied. Polarization study, thermal and X-ray diffraction analysis of the deposits showed the stepwise reduction of perrhenate ion in two stage: the formation of the partly-reduced rhenium oxide film on the cathode, and the reduction of this film to rhenium metal.
Within the cathode potential range more positive than -0.40V vs S. C. E., rhenium oxides of a lower valence state were formed on the cathode and their compositions depended on the cathode potential. With increasing the cathode potential more positive than -0.40 V vs S. C. E., the black deposits containing rhenium of higher oxidation state were obtained, and the composition of the deposits varied to rhenium dioxide with increasing the overpotential. Further, pH of the solution considerably affected the cathode current efficiency of oxide deposition. The optimum pH value for rhenium oxide deposition was found to be 1.65 and the current efficiency decreased with decreasing the pH of the solution.
In the potential range more negative than -0.40 V vs S. C. E., metallic rhenium containing the appreciable amount of lower oxide deposited, which was accompanied by simultaneous hydrogen evolution. Comparison of the conditions which determined the cathode current efficiencies of rhenium metal and lower oxide depositions indicated that metallic rhenium deposition appeared to proceed with preceding lower oxide formation.

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