A new pneumatic separator (Acceleration column type, column constrictions: 1, a tube shaped main separator body column 2. acceleration column, localized at different places of the separator body, defining acceleration zone) is developed. Using disk type copper and aluminum for model samples, separation efficiencies of usual air separator (straight column type) and the developed separator are compared. Separation velocity between 11.8 and 13.0 m/s results in separation efficiencies of about 100% by acceleration column type. On the other hand, straight column type gets to about 100% of efficiency between 12.7 and 13.0 m/s. Separation time that reach to 100% efficiency by acceleration column type is 12 times shorter than that by straight column type. It is considered that an acceleration column type is more advantageous than straight column type in air velocity and separation time that produces about 100% separation efficiency.

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The melting treatment of the incineration residuals (bottom and fly ashes) is an effective method to stabilize the toxic substances (heavy metal, DXN etc.) and to reduce the volume and weight of them for landfill. The ashes had been melted at 1873K. As a result, the bottom ash was separated into slag and metal phases. As for the fly ashes, only slag phase was generated. It was shown that these slags consisted of many kinds of components. Among them, CaO, SiO₂, and Al₂O₃ were major components.
As the first step to control the melting treatment processes, the viscosities of slags generated by melting treatment and the effects of basicity on viscosities of synthesis CaO-SiO₂-Al₂O₃ (Al₂O₃=20mass%) melts had been studied by a crucible-rotating method. The higher basicities of the slags were, the lower the viscosities of them were. The effects of additives on viscosities of synthesis CaO-SiO₂ (CaO/SiO₂=l) and CaO-SiO₂-Al₂O₃ (CaO/SiO₂=l) melts also have been studied. The addition of Al2O3 lead to increase the viscosities of CaO-SiO₂ (CaO/SiO₂=l) melts, and the viscosities of the melts decreased with the addition of the other elements. The addition of fourth component (MgO, TiO₂ and Fe₂O₃) lead to decrease the viscosities of CaO-SiO₂-Al₂O₃ (CaO/SiO₂=l) melts.
More systematic studies about the effects of fourth component on viscosities of CaO-SiO₂-Al₂O₃ melts of constant Al₂O₃ content will be desired.

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In order to recycle the organic waste of scallop mid-gut gland as fertilizer and fish meal, a novel removal process of cadmium contained in scallop mid-gut gland has been developed by using both dilute sulfuric acid leaching and electrowinning.
In this investigation, cadmium removal degree from scallop mid-gut gland was examined under various leaching and electrowinning conditions.
The experimental results obtained are summarized as follows:
1) In advance, sample of scallop mid-gut gland waste was treated to eliminate greasy component because a cathode electrode plate in an electrowinning process was partially covered by the greasy component.
2) The cadmium removal degrees by this process gave the high values from 97% to 98% for leaching time of 3 hours and electrowinning time of 5 hours under the following optimum conditions: sulfuric acid concentration is 0.54 mol/l or 0.9 mol/l, temperature 40°C or 60°C and electrowinning voltage 3.8V or 4.6 V.
3) The cadmium concentration of scallop mid-gut gland waste was reduced to 5 ppm or less (based on dry weight) by this process, and scallop mid-gut gland waste was utilized as fertilizer and fish meal.
4) A novel removal process of cadmium contained in scallop mid-gut gland waste was shown as a flow chart.
5) In this process, cadmium deposits recovered on the cathode electrode plate during the electrowinning may be recycled as mineral resources.

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This paper describes the bioleaching of zinc from seafloor hydrothermal deposit by acidophilic thermophile Acidianus brierleyi. The bioleaching of zinc at 65°C in a batch reactor was carried out most satisfactorily at solution pH of 1.5, initial total cell concentration of 1×10₁₃ cells/m₃ and initial mineral/liquid loading ratio of 5 kg/m₃. Under the conditions determined as optimum, greater than 90% leaching of zinc in the mineral sample (38-53μm) was achieved within 6 days. The Bioleaching rate of zinc for the seafloor hydrothermal mineral sample was compared with that for a land sphalerite sample from the Hanaoka Mine. Nearly identical bioleaching rates were obtained for the two mineral samples from different localities.

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Leached test was used to evaluate the safety of the ferrite sludge formed by conventional, two-step treatments and two-step treatments with pre-treatment by KMnO4. Simultaneously, the concentration of Ni, Fe and Mn ions in the treated water was measured before the leached test. The effect of pre-treatment on the concentration (C) of Ni, Fe and Mn in the elute was discussed by comparing the conventional and two-step treatments.
The C_Ni and C_Mn of ferrite sludge formed by the two-step treatment with pre-treatment were remarkably lower than that by conventional and two-step treatments in relation to Ni(OH)₂ on the surface of ferrite particles. However, the limit in the ability to treat heavy metals decreases in the wastewater containing citric acid. XPS measurement of the sludge formed by conventional and two-step treatment with pre-treatment indicated the existence of Ni(OH)₂ on the surface of ferrite particles. The measurement after Xe+ sputtering showed that the Ni(OH)₂ is present not only on the surface but also in the bulk of the particles formed by conventional treatment.
The two-step treatment with pre-treatment stabilizes the sludge and is favorable for steady operation of the ferrite process, industrial utilization of the sludge and good quality of the treated water.

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