The stability constants of the adducts formed between squareplanar sulphur-coordinated nickel (II) chelates and N-bases are obtained from spectrophotometric measurements in benzene solution at 25°C.
The effects of sulphur coordinating ligands, N-bases and solvents on the stability of the adducts are discussed and those results are applied to the surface reactions between the surfaces of sulfide minerals and collector reagents such as xanthates and aerofloats.

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The solubilities of cadmium, zinc, nickel and cobalt sulfates have been measured in the temperature range 100°C to 300°C, by a direct sampling method using a zirconium autoclave. The obtained results are as follows;(1) The solubilities of these sulfates at above 100°C decrease sharply with increasing temperture, and show just slight value at 200°C to 300°C.
(2) The forms of equilibrating solid phases within a temperature range investigated were confirmed to be CdSO₄, ZnSO₄·H₂O, NiSO₄·H₂O (above 140°C) and CoSO₄·H₂O, respectively.
(3) The solubility of cadmium sulfate obtained shows good agreement with previous data and was first established by the present work at above 190°C.
(4) The obtained solubility of zinc sulfate at above 120°C shows somewhat different tendency from the previous data, and the solubility at above 250°C was newly established.
(5) The solubility data for nickel and cobalt sulfates agree well with those obtained by Gesell et al., whose data were limited at above 160°C. The data below 160°C were also established, but the form of equilibrating solid nickel sulfate below 140°C could not be comfirmed experimentally.
(6) Some thermodynamic considerations were carried out using the data obtained for nickel and cobalt sulfates.

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A kinetic study of the gaseous reduction of tin silicate with carbon monoxide was made by using the thermo balance over the temperature range from 650 to 850°C.
The reduction rate curves obtained were shown that there are two rate-determining steps.
The initial step is assumed to be the phase boundary reaction between tin silicate and carbon monoxide, this is then followed by the slow reduction that the diffusion of the reactants in the solids is the rate-determining step.
The addittion of CaO to the silicate in the range of 50-70% increased markedly the reduction rate and prolonged the initial reduction periods.
The apparent activation energies for the initial reduction period in the case of adittions of CaO 50% and 75% were 30.5 and 22.0 kcal/mole respectively.

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The two kinds of ores from UCHINOTAI ore deposits and each of their main mineral components were oxidized in dried air at temperatures from 200 to 700°C, respectively. The ores were ground under 200 mesh. The oxidation behaviors were observed by means of chemical analysis, X-ray diffraction, and thermobalance.
1. The copper rich ore consisted mainly of copper pyrite and pyrite is found to be more oxidizable, and more easily sulphatized than the samples of simple pyrite or simple copper pyrite and behaves in the oxidation as in the case of the mixtures of copper pyrite and pyrite.
2. The zinc rich ore consisted mainly of sphalerite, pyrite and minor copper pyrite behaves in the oxidation as in the case of the mixture of their components and the sulphatization of the ore is found to be stimulated by the presence of copper pyrite or pyrite in the ore.

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The distribution ratios of gold, silver and selenium between liquid copper and cuprous sulfide, L_x (X=Au, Ag or Se), have been measured at 1, 200°C and the results obtained are summarized as follows:
1) L_Au =171.5 (Au content in copper phase up to 1%)
L_Ag=2.37 (Ag content in copper phase up to 7%)
L_se=0.074 (Se content in copper phase up to 1.2%)
These ratios are independent of the concentrations below the maximum experimental values indicated in brackets.
2) The distribution ratio of gold, L_Au is not affected by silver (Ag content in copper phase up to 4. 5%), and that for silver, L_Ag is uninfluenced by gold (Au content in copper phase up to 1%).
3) The distribution ratios of siver and selenium, L_Ag and L_se in the Cu-Ag-Se-S system (Ag content up to 7%, Se content up to 0.15% in copper phase) are hardly changed by adding ways of silver and selenium, i. e. as the chemical compound Ag₂Se or separately. Moreover, there are no significant differences between these ratios and L_Ag in the Cu-Ag-S system or Lse in the Cu-Se-S system. The affinity between silver and selenium, therefore, is thought to be weak.
On the basis of these distribution ratios, some discussions were made on the behaviors of gold, silver and selenium in the blister making period of copper converting and in the blister making zone of the copper continuous smelting process.

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