The thermal cutting is thought to be more favorable to rock-like materials than to metals, since, generally, their thermal conductivities are lowerer than those of metals.
Results obtained in case of the cement mortar, as an example of such materials, are as follows.
(1) The depth of cut in this case becomes two or three times greater as compared with the case of cast iron.
(2) The finer the aggregate (silica sand) in the cement mortar is, the greater the depth of cut may be.
(3) The depth of cut increases as the mixing ratio of fine aggregate to cement becomes larger.
The above-mentioned phenomena may be due to the secondary melting action of the dross, because the heat flow from the dross to the cement mortar is little owing to the low thermal conductivity of the mortar. Furthermore, these phenomena are also due to the reduction of heat quantity required to melt the cement mortar by increasing SiO₂ component in the molten cement mortar and to the scratching action of the separated fine aggegate.

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The pH dependence of copper activation on sphalerite was studied by measuring the adsorption of copper ion as a function of pH. The adsorption of copper ion was maximum at about pH=5-6 and decreased rapidly in both the acid and alkaline region. From the result, it was recognized that the pH dependence for the adsorption of copper ion on sphalerite was remarkable.
The cause for the decrease of the copper ion adsorption in the alkaline region was investigated. The dependence of copper ion concentration for the copper ion adsorption on sphalerite was examined. As a result, it was recognized that the copper ion adsorption on sphalerite decreased with lowering copper ion concentration.
Then, the kinetics for the adsorption of copper ion on sphalerite was investigated. The reaction rate of the copper ion adsorption on sphalerite was shown by the reaction equation of 1st order, and the log-log plot of relations between the copper ion adsorption rate and the agitation rate was characterized by a straight line.
The above results presented that the decrease of the copper ion adsorption in the alkaline region might be due to the decrease of the copper ion concentration with the increase of the pH value, and consequently to the decrease of diffusion rate at which copper ion diffused to the surface of sphalerite from the bulk in solution.
The cause for the decrease of the copper ion in the acid region was analysed experimentally. As a consequence, it was surmised that the copper sulphide formation led to the decrease of the copper ion concentration in solution. Accordingly, the decrease of the copper ion adsorption in the acid region might be due to the decrease of the copper ion concentration and to the diffusion rate of copperion.

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The electrolyte compositions and operating conditions for the electrolytic refining of tin from tin amalgam have been investigated. The current efficiencies both of the electrolytic deamalgamation of the tin amalgam anode and of the clectradeposition of tin at the cathode were measured and the adherence of the tin deposit was examined. The following results were obtained.
1) SnCl₂; 0.1 mol/l, HCl; 0.25 N, and dodecylpyridinium chloride; 0.5g/l were the most suitable electrolyte composition. The cationic surfactant (dodecylpyridinium chloride) was added to get the adherent tin deposit. Anodic current density; 2.8 A/dm², cathodic current density; 2.4A/dm², and bath temperature; 60°C were the best operating condition. Under these electrolytic conditions, the anode and cathode efficiencies were approximately 100%, and the adhesion of the tin deposit was excellent.
2) Mercury and indium in the tin amalgam anode never dissolved into the electrolyte during the electrolysis.

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The current investigation has been undertaken to define the conditions of the roasting and ammonia pressure leaching for the recovery of nickel from laterite ores.
The recovery of nickel is mainly effected by the roasting time, temperature and the flow rate of CO gas during the reducing roasting. On the other hand, the following factors such as the pressure of oxygen, temperature, the rate of stirrer and the concentrations of ammonia and ammonium sulphate are important for the recovery of nickel reduced by the ammonia pressure leaching.
The results obtained were summerized as follows. Satisfactory reduction of laterite ores prior to the pressure leaching was attained by the roasting at 900°C for 2 hours under the flow of CO gas in the rate of 200cc/min.
When the leaching was carried out under the optimum conditions; temperature 100°C, oxygen partial pressure 2 atm, stirrer rate 500 rev/min, concentrations of ammonia and ammonium sulphate 3mol/l and lmol/l, the extraction of nickel exceeded more than 95%. The results obtained showed an approximate agreement with that of metallic nickel powder which were described in a previous paper.

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Activities of copper and indium in liquid Cu-As and Cu-In alloys have been measured by means of the galvanic cell:
(-) Cu (s or l) |Cu⁺, (KCl-NaCl) |Cu-As (l)(+)
(-) In (l) |In⁺, (KCl-NaCl) |Cu-In (l)(+)
Owing to the high vapor pressure of arsenic, the measurements for the copper-arsenic system were limited in the range up to NAs=0.305. The electromotive forces of the cell at temperatures below the melting point of copper were corrected with the term expressed by the function of free energies of fusion of copper at experimental temperatures. Activities of arsenic were determined by integrating the values ofαfunction calculated from acu.As the lower limit of the integration, it is used the activity of arsenic at NAs=0.27 obtained by meams of the transportation method. Activity of arsenic thus obtained shows a considerable negative deviation from Raoult's law, andγ^o_As at 1, 000°C is estimated as low as 1.45·10-4.
Measurements for the copper-indium system were made in the ranges 0.201 to 0.799 in NIn and 700°to 1, 000°C. Deviations of the activities of copper and indium from the ideality are positive for the indium rich side and are negative in the copper rich region of the system. The value ofγ^o_In is estimated 0.27 at 1, 000°C.

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The molten salts, sodium fluoride-barium chloride-aluminum fluoride system, are known as “Gadeau's bath” in the electrolytic refining of aluminum.
The melting points and densities of this system were already reported by the author.
In this paper, the electrical conductivities of some compositions of NaF-BaCl₂ binary system and NaF-BaCl₂-AlF₃ ternary system were determined by using a conductance cell of a platinum crucible combined with a platinized platinum wire.
1) The measuring values of the specific conductivity of the molten mixtures of the binary system NaF-BaCl₂ are 5.17-2.18 ohm-1 cm^-1 at 1000°C.
When the content of barium chloride increases, the specific conductivity decreases.
2) In the binary system, the following displacement reaction occurs.NaF+BaCl₂=NaCl+BaFCl
Calculated specific conductivities of this binary system, assuming the additivity of the conductivity of each salt and the displacement reaction, accord well with measured ones.
3) The values of the molten mixtures of the ternary system NaF-BaCl_2-AlF₃are 3.3-0.6 ohm^-1cm^-1at 850°C
When the content of barium chloride is kept constant, the specific conductivity decreases almost linearly with the increase of aluminum fluoride content, because of the formation of the compound Na₃AlF₆and NaAlF₄. And when the content of barium chloride increases, the conductivity decreases also because of the decrease of the sodium fluoride content and the formation of BaFCl.
4) The specific conductivity of the Gadeau's bath is 0.88 ohm^-1 cm^-1at 850°C and 0.82 ohm^-1cm^-1 at 800°C
5) In this ternary system, the following compositions show the comparatively low melting temperatures and suitable densities as the refining electrolyte and have better specific electrical conductivities than that of the Gadeau's bath partially.
NaF 10-35%, BaCl₂50-70%, AlF₃5-25%.

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