There is an increasing trend in the copper smelters to recycle electronic materials, which contain relatively high concentration of platinum group metals. Platinum group metals lost in the slag is increasing with increasing of treated scrap amount. To determine the portion of the platinum group metals chemically dissolved in the slag will be a key factor to improve the recovery of those metals. An experimental study was carried out to determine the solubility of platinum in FeO_x-SiO₂ slag equilibrated with a pure platinum and the liquid Pt-Cu alloy at 1573 K and the range of oxygen partial pressure from 10^-9 to 10^-6. The solubility of platinum in the slag tends to increase with increasing oxygen partial pressure and content of copper in the slag. Based on the measured platinum solubility, activity coefficients of platinum oxide in the FeO_x-SiO₂ slag were derived. The activity coefficients decrease by increasing copper contents in slag. Therefore, lower copper content in the slag tend to lower precious metals dissolution in the slag.

The activity coefficients of MnO and FeO in an FeO-MnO-MgO-P2O5-SiO2(-CaO) slag system were measured on the basis of the equilibrium between Ag and molten slag at 1 673 K under a controlled atmosphere. On the basis of experimental results, the activity coefficients of MnO and FeO in this multicomponent slag were evaluated using a regular solution (RS) model, FactSage, and an empirical formula. In the case of the RS model, the interaction energies and conversion factors to fit the calculated values to experimental results were reassessed. By the used of the empirical formula, FactSage and the regular solution model of present work, the activity coefficient ratio of MnS and FeS in a Fe-Mn-O-S matte that was equilibrated with a FeO-MnO-MgO-P2O5-SiO2 slag system was evaluated. When the RS model was used to calculate the gamma(MnO)/gamma(FeO) ratio, the gamma(MnS)/gamma(FeS) ratio decreased slightly with an increase in the X-MnS/X-FeS ratio. In contrast, when the empirical formula and FactSage were used, the gamma(MnS)/gamma(FeS) ratio was almost constant when the X-MnS/X-FeS ratio was increased.

We have proposed a novel process for recycling Mn wasted in steelmaking slag via sulfurization to separate P from Mn. For clarifying the efficient recovery of Mn from steelmaking slag, the influences of slag basicity and temperature on the distributions of Mn and Fe between the Fe-Mn-Ca-O-S matte and FeO-MnO-MgO-P2O5-SiO2-CaO slag were investigated. The distributions of Fe and Mn between the matte and the slag increased with an increase in the slag basicity. Moreover, when log P-S2 (P-S2: partial pressure of S) was more than -2, the Mn distribution increased to be more than 10 as the slag basicity increased beyond 1.7. Even though the effects of slag basicity and P-S2 on the Mn content in the matte were small, the behavior of Mn in the matte was dependent on temperature. In order to understand the behavior of Mn and Fe in steelmaking slag and matte, the relationship between the activity coefficient ratio of MnS and FeS (gamma(MnS)/gamma(FeS)) and the mole fraction ratio of MnS and FeS for the matte was investigated. To evaluate gamma(MnS)/gamma(FeS) for the matte, the activity coefficient ratio of MnO and FeO (gamma(MnO)/gamma(FeO)) was estimated using an empirical formula and the RS model, and the mole fractions of MnS and FeS in the matte were calculated on the basis of mass balance. The results revealed that the values of gamma(MnS)/gamma(FeS) for the Fe-Mn-S-O matte were about twice those for the Fe-Mn-Ca-S-O matte. Moreover, gamma(MnS)/gamma(FeS) for the Fe-Mn-Ca-S-O matte decreased with an increase in temperature.

The authors proposed an innovative process for recovering Mn from steelmaking slag. The process starts with the sulfurization of steelmaking slag to separate P from Mn by the formation of a liquid sulfide phase (matte). Then, the obtained matte is weakly oxidized to make a Mn-rich oxide phase without P. High-purity Fe-Mn alloys can therefore be produced by the reduction of the Mn-rich oxide phase. However, to the authors' knowledge, the sulfurization of molten slag containing P and Mn has not been sufficiently investigated. It was recently found that P was not distributed to the matte in equilibrium with the molten slag. To gain knowledge of the process's development, it is important to investigate the influence of the partial pressures of sulfur and oxygen on the equilibrium distribution of Mn and Fe between the matte and the molten slag. In the current work, a mineralogical microstructure analysis of the matte revealed that the existence of the oxysulfide and metal phases was dependent on the partial pressure of sulfur and oxygen. The Mn content of the matte increased with partial pressure of sulfur while the O content of the matte decreased. In contrast, the ratio of Mn/Fe in the matte was constant when the metal phase of the matte was observed at a log below -11. These results also corresponded to the relationship between the activity coefficient ratio of MnS/FeS and the mole fraction of MnS/FeS in the matte. The gamma (MnS)/gamma (FeS) value decreased exponentially as the mole fraction of MnS/FeS increased.

In our previous paper, a slag modification process involving the mixing of stainless steelmaking and nonferrous smelting slags was proposed for preventing the disintegration of the stainless steelmaking slag. In order to use this method, the behavior of heavy metals especially PbO contained in the nonferrous slag has to be assessed. In the present study, the activity coefficient of PbO in CaOSiO 2- Fe tO-Al 2O 3-MgO and CaO-SiO 2-Fe tO slags saturated with iron was measured at 1673 K. The results showed that the activity coefficient of PbO increased with basicity and had a maximum value when the basicity was approximately 1.0. The equilibrium PbO content in the modified slag had a minimum value that corresponded to a mixing ratio of 0.6. The trend was similar to the change in the removal ratio of PbO observed in the previous study. Therefore, the change in the oxygen potential and the change in the activity coefficient of PbO can be considered the cause of this trend. © 2012 De Gruyter.

High-temperature heat content of stainless steel of SUS304 was measured over the temperature range 600 to 1850 K using a drop-calorimeter. The enthalpy of fusion of SUS304 was determined as 230 +/- 0.18 J g(-1) at the liquidus point of 1719 +/- 3 K. The heat content and heat capacity equations were derived by Shomate function for the solid compounds and least square method for the liquid phase.

We propose a novel process to recycle Mn from steelmaking slag. The first step is to sulfurize the slag, producing a liquid sulfide phase (matte) without P. High-purity Fe-Mn alloys can then be made by desulfurizing the matte. However, to our knowledge, there have been no reports to date concerning the sulfurization of P and Mn contained in molten slag. Therefore, knowledge of the distribution of Fe, Mn and P between the matte and the molten slag is required to determine the feasibility of this process. In this study, the equilibrium distributions of Mn, Fe, Ca and P between a FeS-MnS matte and FeO-MnO-SiO2-MgO-P2O5 slag with/without CaO are investigated under controlled partial pressures of oxygen and sulfur. It was found, as P is not present in the matte, that a separation of P from Mn was accomplished. The increament of (CaO+MgO)/SiO2 in slag can improve the concentrations of Mn and Fe in the matte. The content of Ca in the matte was less than 2 mass%, even when the concentration ratio of CaO/SiO2 in the slag was unity.

The sodium and chromium contents in copper or lead smelting slags are increasing with the increase in waste recycling. The lead solubility in the slag is important from both an economical and environmental perspective. As a fundamental study, experiments have been carried out to determine the equilibria between the FeOx-CaO-SiO2-5mass% NaO0.5 or FeOx-CaO-SiO2-5mass%CrO1.5 slags and lead metal in iron crucibles at 1573 K. It has been found that addition of soda decreases the lead solubility in SiO2 rich side of the slag, while soda increases the solubility in CaO rich side. Chromium in the slag decreases the lead solubility in the FeOx-CaO-SiO2 slag. The activity coefficients of PbO in the FeOx-CaO-SiO2-5mass%NaO0.5 or FeOx-CaO-SiO2-5mass%CrO1.5 slags were compared with those of the CaO-SiO2-FeOx ternary system.

Continuous converting of copper matte based on calcium ferrite slag of the CaO-FeOx-Cu2O system is an attractive technology for copper smelting This slag containing approximately 20 mass% CaO can prevent the excess magnetite precipitation, but sometimes tends to separate CaSO4 under a high oxygen potential required to produce copper metal.
To clarify the mechanism of gypsum formation, the precipitation of CaSO4 in the CaO-FeOx-Cu2O slag system equilibrating with blister copper has been determined at 1473, 1523 and 1573 K under the SO2 partial pressures of 0.2, 0.4, 0.6 and 1 atm. It was found that the formation of CaSO4 in the CaO-FeOx-Cu2O slags is enhanced with decreasing temperature, increasing SO2 partial pressure or CaO content and also increasing oxidation degree of the blister copper. The behavior of CaSO4 formation in the slag is also discussed thermodynamically based on the free energy calculations combining with the activity data derived from Prof. Takeda's data on the CaO-FeOx-Cu2O ferrite slag diagram. Both of experimental and thermodynamical results show good agreements in general.
It is found that the decreasing temperature, increasing CaO content or SO2 pressure, and extensive oxidation of the blister copper tend to separate CaSO4.

Distributions of Sn, Sb, and Bi between Ag-Pb alloy and PbO based melt were investigated at 1273 K. A chemical equilibrium technique was used in order to measure the distributions. The oxygen partial pressure equilibrated with the melts was measured by an EMF method. The distribution ratios were defined as the weight ratios of Sn, Sb, and Bi in PbO divided by those in the Ag-Pb phase. The obtained distribution ratios were plotted against the logarithm of the oxygen partial pressure. The plots showed that the distribution ratios of Sn, Sb, and Bi increased with an increase in the oxygen partial pressure. Taking the slope of these plots, the oxide forms of the minor elements dissolved in the PbO based melt could be estimated. Sn dissolves in PbO based melts as SnO2 in the oxygen partial pressure range, P-O2 = 10(-7.5)-10(-4). Depend on the concentration of Sn in PbO and that in Ag, the activity coefficient of SnO2 in the PbO based melt at 1273 K was determined to be 62,000. The activity coefficient of BiO1.5 decreases with increasing oxygen partial pressure and that of SbO1.5 increases with increasing oxygen partial pressure. The distribution behavior of such minor elements was compared with that of Ag, and the efficiency of oxidation in the removal of such impurities from Ag was investigated. [doi: 10.2320/matertrans.M2009117]

The equilibration of a Ag-Pb-based melt with PbO-NaO0.5 and PbO-CaO melts at 1273 K was investigated. A chemical equilibrium technique was used to carry out measurements. The oxygen partial pressure was measured by an electromotive force (EMF) method. The activity coefficient of AgO0.5 in the PbO-NaO0.5 and PbO-CaO melts and that of PbO in the PbO-NaO0.5 melt was derived. The addition of NaO0.5 to the PbO-based melt resulted in a slight decrease in the activity coefficient of AgO0.5. However, the activity coefficient of PbO decreased remarkably with an increase in the concentration of NaO0.5 in the PbO-based melt. Therefore, improved phase separation of Ag from the PbO-based melt was achieved by the addition NaO0.5. The addition of CaO in the PbO-based melt did not cause any change in the activity coefficient of AgO0.5. [doi:10.2320/matertrans.M2009036]

Waste gypsum from construction materials have to be recycled legally in Japan.
Combustion of plastics containing halogen may generate halide gas. Stabilization treatment of halogen element should be done. In the present study the reaction between the plastics and gypsum generating calcium halide Such as CaCl2 or CaF2 had been investigated. Reaction condition was evaluated thermodynamically, and experiment for generating CaCl2 and CaF2 was conducted. CaCl2 was formed from CaSO4 and chloroethylene at 1273K. CaF2 was formed over 1173K. Crystal water of CaSO4 accelerates the reaction Forming CaF2.

The distribution ratio of Se between Ag-Pb alloy and PbO phases was investigated at 1273 K. A chemical equilibrium technique was used for the measurement. The oxygen partial pressure was in equilibrium with both the phases, and it was measured by an EMF method. The distribution ratio, defined as the mole fraction of Se in PbO to the mole fraction of Se in metal, was plotted against the oxygen partial pressure. The distribution ratio decreased with an increase in the oxygen partial pressure. The slope of the plot indicates that Se dissolves in the PbO phase as oxide, which is unreasonable. The activity coefficient of Se in the Ag-Pb alloy was also measured, and it was found to decrease with an increase in the concentration of Ag. Se dissolved in the PbO phase in the non-oxide form. The activity coefficient of Se in Ag was estimated as 0.0009 at 1273 K. [doi: 10.2320/matertrans.M2009021]

Waste gypsum from construction materials have to be recycled legally in Japan.<br>Combustion of plastics containing halogen may generate halide gas. Stabilization treatment of halogen element should be done. In the present study, the reaction between the plastics and gypsum generating calcium halide such as CaCl<sub>2</sub> or CaF<sub>2</sub> had been investigated. Reaction condition was evaluated thermodynamically, and experiment for generating CaCl<sub>2</sub> and CaF<sub>2</sub> was conducted. CaCl<sub>2</sub> was formed from CaSO<sub>4</sub> and chloroethylene at 1273K. CaF<sub>2</sub> was formed over 1173K. Crystal water of CaSO<sub>4</sub> accelerates the reaction forming CaF<sub>2</sub>.

Most of waste plaster board, which contains gypsum has been buried in the landfill. However, this treatment of waste gypsum board is becoming a serious problem due to lack of landfill capacity, and secondary pollution by toxic substance. In this study, we focused a recycle of calcium resources as CaO or CaS from the waste gypsum, and developed a reduction process of the gypsum using plastics at high temperature. Reduction behavior of CaSO<SUB>4</SUB> by Polyethylene at temperature from 1273 to 1573K was studied with gravimetry and X-ray diffraction analysis. From the experimental results, we found that increasing CaSO<SUB>4</SUB>-CH<SUB>2</SUB> gas interface tend to advance the reduction of CaSO<SUB>4</SUB>. Furthermore, direct formation of CaS from CaSO<SUB>4</SUB> was observed only at temperature of 1273K without an intermediate compounds stage, and the reduction sequence was CaSO<SUB>4</SUB>→CaO→CaS at temperatures higher than 1373K. Finally, the sequence of reduction process for CaSO<SUB>4</SUB> was discussed on the potential diagram of the Ca-S<SUB>2</SUB>-O<SUB>2</SUB> system.

Most of waste plaster board, which contains gypsum has been buried in the landfill. However, this treatment of waste gypsum board is becoming a serious problem due to lack of landfill capacity, and secondary pollution by toxic substance. In this study, we focused a recycle of calcium resources as CaO or CaS from the waste gypsum, and developed a reduction process of the gypsum using plastics at high temperature. Reduction behavior of CaSO₄ by Polyethylene at temperature from 1273 to 1573K was studied with gravimetry and X-ray diffraction analysis. From the experimental results, we found that increasing CaSO₄-CH₂ gas interface tend to advance the reduction of CaSO₄. Furthermore, direct formation of CaS from CaSO₄ was observed only at temperature of 1273K without an intermediate compounds stage, and the reduction sequence was CaSO₄→CaO→CaS at temperatures higher than 1373K. Finally, the sequence of reduction process for CaSO₄ was discussed on the potential diagram of the Ca-S₂-O₂ system.

During the decommissioning phase of a nuclear reactor, most of the steel-reinforced concrete shielding around a pressure vessel is considered as low-level radioactive waste. It is highly desirable to reduce the radioactivity level of this waste to below the clearance level. Normally, the radioactivity of steel after irradiation is found to be proportional to the cobalt content. In this study, for the production of low-activation steel in steelmaking process, cobalt distribution between MgO-saturated FeOx-MgO-CaO-SiO, slag and Fe-Cu-Co molten alloy was investigated. The results are summarized as follows: (1) the distribution ratio increases with decreasing temperature and (2) the activity coefficient of CoO decreases with increasing temperature and decreasing slag basicity. Although low temperature and low basicity are suitable conditions for refining, it is extremely difficult to decrease the Co content by an oxidation reaction, because of a very small distribution ratio of cobalt. [doi:10.2320/matertrans.MAW200831]

The activity coefficient of strontium in a copper melt has been investigated by a chemical equilibrium technique in the temperature range from 1473 to 1773 K. A graphite crucible was used to control the oxygen partial pursuer in CO gas. The activity coefficient was derived from the standard free energy of formation of SrO, the oxygen partial pressure, and the concentration of strontium in copper.
The standard free energies of formation for Sr0.6Al2O3 and Sr0.2Al2O3 at 1723 K are also derived by equilibrating Al2O3, SrO center dot 6Al(2)O(3), and SrO center dot 2Al(2)O(3) with Cu.

High temperature heat contents of the Cu-Zr system alloys were measured over temperature range from 880 to 1470 K using a drop calorimeter. The enthalpies of fusion of some solid compounds were determined by the heat content-temperature plots and the entropies of fusion were calculated. Enthalpies of mixing in the liquid Cu-Zr system were measured by high temperature reaction calorimetry in the concentration range of x(Zr) = 0.182-0.667 at 1443 K. This system has negative enthalpies of mixing over the measured concentration range. The standard enthalpies of formation at 298.15 K of Cu9Zr2, Cu51Zr14, Cu8Zr3, Cu10Zr7 and CuZr2 compounds were determined from the obtained data for the heat contents and enthalpies of mixing. Based on the experimental data, published thermodynamic and phase diagram data, the Cu-Zr binary system was analyzed using Redlich-Kister polynomial equation. The thermodynamic properties and the phase diagram calculated from the optimized parameters agree well with the experimental data. (C) 2007 Elsevier B.V. All rights reserved.

Phase equilibrium and oxygen partial pressure for the Fe-S-O system from eutectic temperature to 1673 K were investigated by chemical equilibrium techniques and the EMF method. The liquid phase is saturated with Fe, FeO, Fe3O4 and FeS. The partial pressure of oxygen increases remarkably with departing from the liquidus saturated with Fe. According to the Gibbs-Duhem equation and Schumann's method, the activities of Fe and the partial pressure of S-2 for the liquid phase are derived.

Activity coefficient of AgO0.5 in PbO-SiO2 melt equilibrated with Ag-Pb alloy in an alumina or a magnesia crucible was investigated at 1273 K. A chemical equilibrium technique was applied to the measurement. The oxygen partial pressure was also measured by an EMF method. The activity coefficient of AgO0.5 in the PbO-SiO2 melt was derived.
The addition Of SiO2 in the PbO melt decreases dissolution of Ag into the oxide phases. However, the activity coefficient of AgO0.5 increases slightly with an increase in the concentration of SiO2 in the PbO melt.

Waste gypsum from construction materials have to be recycled legally in Japan. The waste gypsum contains CaSO<SUB>4</SUB> and other materials such as papers. And thus it is impossible to reuse them directly as a CaSO<SUB>4</SUB> resource. A treatment at higher reaction temperature seems to be suitable for recycling a large quantity of the gypsum. However, CaSO<SUB>4</SUB> is rather stable even at high temperature, therefore cost-intensive reactants are necessary.<BR>Re-generation of CaO or CaS from CaSO<SUB>4</SUB> was investigated using waste plastics, which were considered as reduction agent. Thermodynamic simulation was employed to find optimal conditions for reduction of CaSO<SUB>4</SUB>. Reduction experiments were conducted using reagents of CaSO<SUB>4</SUB> and polyethylene. CaO was formed from CaSO<SUB>4</SUB> and polyethylene mixture over 1273K in air. Crystal water of CaSO<SUB>4</SUB> accelerates the reaction forming CaO. Plastics can be successfully used to produce CaO and CaS from CaSO<SUB>4</SUB> in controlled atmosphere.

Waste gypsum from construction materials have to be recycled legally in Japan. The waste gypsum contains CaSO₄ and other materials such as papers. And thus it is impossible to reuse them directly as a CaSO₄ resource. A treatment at higher reaction temperature seems to be suitable for recycling a large quantity of the gypsum. However, CaSO₄ is rather stable even at high temperature, therefore cost-intensive reactants are necessary.<BR>Re-generation of CaO or CaS from CaSO₄ was investigated using waste plastics, which were considered as reduction agent. Thermodynamic simulation was employed to find optimal conditions for reduction of CaSO₄. Reduction experiments were conducted using reagents of CaSO₄ and polyethylene. CaO was formed from CaSO₄ and polyethylene mixture over 1273K in air. Crystal water of CaSO₄ accelerates the reaction forming CaO. Plastics can be successfully used to produce CaO and CaS from CaSO₄ in controlled atmosphere.

A clear phase separation into liquid iron-rich and copper-rich alloys was observed when a mixture of Fe, Cu and P was melted in an alumina or carbon crucible at 1373 K. Since this phase separation is considered to be useful for recovering valuable copper from iron-base alloy scraps, the phase equilibrium in the Fe-Cu-P and Fe-Cu-P-C systems was investigated in this study. The effect of carbon to the phase separation was determined in the concentration range of phosphorous between 7 and 11 mass% at 1373 K. It was found that the addition of carbon enlarged the miscibility gap of the Fe-Cu-P system. Distribution ratios of some minor elements of An, Ag, Pd, Pt, Rh, Cr, Mn and Ni between the liquid iron-rich and copper rich phases were also measured at 1373 K. It was found that An, Ag and Pd were enriched in the copper-rich phase, while Pt and Mn were distributed in both phases, and Rh, Cr and Ni preferentially in the iron-rich phase.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect Of SiO2 and CaO on the melting temperature is quantified.
The effect Of CU2O is also quantified through the model. Some Fe/CaO versus CU(2)o and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, CU2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting
If the ferrous calcium silicate slags and the so called "fayalite" slag are looked as continuation of each other it can be seen that lime at the start increases the liquidus temperature in the magnetite field but decreases it if higher lime is added and we get closer to the ferrous calcium silicate slag. It should be noted that these conclusions should not be generalized since different conditions in various furnaces and various minor oxides such as alumina and magnesia may completely change the above stated relationships.
It also should be kept in mind that in the industrial practice the liquidus surface is important along with other factors such as slag volume, refractory protection, copper metal recovery, OF blister composition etc. and these factors need to be taken all into consideration when a proper slag composition is chosen. These are subject of the author's previous and continuous research.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified.
The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting.
If the ferrous calcium silicate slags and the so called "fayalite" slag are looked as continuation of each other it can be seen that lime at the start increases the liquidus temperature in the magnetite field but decreases it if higher lime is added and we get closer to the ferrous calcium silicate slag.
It should be noted that these conclusions should not be generalized since different conditions in various furnaces and various minor oxides such as alumina and magnesia may completely change the above stated relationships.
It also should be kept in mind that in the industrial practice the liquidus surface is important along with other factors such as slag volume, refractory protection, copper metal recovery, blister composition etc. and these factors need to be taken all into consideration when a proper slag composition is chosen. These are subject of the author's previous and continuous research.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified.
The effect Of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect Of SiO2 and CaO on the melting temperature is quantified.
The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, CU2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect Of SiO2 and CaO on the melting temperature is quantified.
The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, CU2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOX-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the mclting temperature is quantified.
The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and FE/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect Of SiO2 and CaO on the melting temperature is quantified.
The effect Of CU2O is also quantified through the model. Some Fe/CaO versus CU2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
Some discussions are also presented taking into account plant observations and important conclusions are drawn for copper smelting and converting.
If the ferrous calcium silicate slags and the so called "fayalite" slag are looked as continuation of each other it can be seen that lime at the start increases the liquidus temperature in the magnetite field but decreases it if higher lime is added and we get closer to the ferrous calcium silicate slag.
It should be noted that these conclusions should not be generalized since different conditions in various furnaces and various minor oxides such as alumina and magnesia may completely change the above stated relationships.
It also should be kept in mind that in the industrial practice the liquidus surface is important along with other factors such as slag volume, refractory protection, copper metal recovery, blister composition etc. and these factors need to be taken all into consideration when a proper slag composition is chosen. These are subject of the author's previous and continuous research.

While calcium ferrite slags have been successfully used in continuous copper converting for the last 30 years, ferrous calcium silicate slag was proposed about 8 years ago as an additional alternative for copper smelting. Although both slags are normal extensions of each other their phase relations have not been completely clarified. In this paper the liquidus relations of both slags have been quantified at various areas that cover both of them.
The existing experimental data have been first reviewed and discussed in relation to the solidification procedure. An original physical model is then used to predict various diagrams of the liquidus surface of both slags.
It is shown that the ternary liquidus diagrams normally used for FeOx-SiO2-CaO system are not suitable for industrial slags. The new model diagrams of Fe/CaO versus SiO2 and Fe/SiO2 versus CaO as well as Fe/CaO versus Temperature and Fe/SiO2 versus temperature are proven to be much more convenient for ferrite and ferrous calcium silicate slags. Based on these diagrams the effect of SiO2 and CaO on the melting temperature is quantified.
The effect of Cu2O is also quantified through the model. Some Fe/CaO versus Cu2O and Fe/SiO2 versus CaO at various copper contents are predicted and the results show good agreement with the experimental data. It is also shown that in the presence of liquid copper, Cu2O is dissolved in the slag depending on the oxidation degree of the system and might lower the liquidus temperature.
If the ferrous calcium silicate slags and the so called "fayalite" slag are looked as continuation of each other it can be seen that lime at the start increases the liquidus temperature in the magnetite field but decreases it if higher lime is added and we get closer to the ferrous calcium silicate slag.
It should be noted that these conclusions should not be generalized since different conditions in various furnaces and various minor oxides such as alumina and magnesia may completely change the above stated relationships.
It also should be kept in mind that in the industrial practice the liquidus surface is important along with other factors such as slag volume, refractory protection, copper metal recovery, blister composition etc. and these factors need to be taken all into consideration when a proper slag composition is chosen. These are subject of the author's previous and continuous research.

The zinc, lead and alumina contents in copper smelting slag are increasing with the increase in waste recycling. The recovery of base metals such as lead and zinc from copper converter slag is important from both an economical and environmental perspective. As a fundamental study of the metal recovery by reduction process, activity coefficients of ZnO and PbO in the CaO-SiO2-FeOx-5mass%AlO1.5 slag under iron saturation at 1573K are derived from the data of slag-metal equilibrium experiments. On the basis of the obtained data, the activity coefficients of ZnO and PbO in the CaO-SiO2-FeOx-5mass%AlO1.5 slag were compared with those of the CaO-SiO2-FeOx ternary system. Addition of alumina increases activities coefficient of ZnO and PbO in SiO2 rich side of the slag, and decreases them in CaO rich side.

There is an increasing trend in the copper smelters to recycle electronic materials, which contain relatively high concentration of precious metals. As a consequence, the amount of precious metals lost in the slag phase is increasing. To determine the portion of the precious metals chemically dissolved and that associated with the mechanically trapped matte in the slag will be a key factor to improve the recovery of those metals. Thus, an experimental study was carried out to determine the distribution of precious metals (Xu, Pt, Pd, Rh, Ru) between the equilibrated copper matte and iron-silicate slag phases. The experiments were made in a magnesia crucible at 1573 K and a fixed partial pressure of SO2 of 0.1 atm for the matte grades between 40 and 70 mass% of copper. It was found that the distribution ratios (defined as mass% X in slag/mass% X in matte, where X represents the precious metal) are around 10(-2) for Ru, 10(-3) for An, Pt and Pd and 10(-4) for Rh. The distribution ratios show a tendency to increase when the grade of matte is increased.

Sulphur, with its multiple oxidation states, play critical roles in many processes, ranging from regulating enzymes in plants, to acidifying aquatic systems, and to affecting the global climate. Most of non-ferrous smelters have been contributing to reduce atmospheric emissions of sulfur dioxide to acceptable levels, converting it to sulphuric acid and/or gypsum. However, some amount of SO2 gas is still emitted from isolated smelters. Furthermore, sulphuric acid is competing with involuntary elemental sulphur in the market. This situation puts the non-ferrous metallurgical industries to develop a new sulphur fixation process.
This paper briefly describes the new technologies for fixation, followed by the novel proposal to convert SO2 gas to elemental sulphur using organic materials. Finally, the feasibility will be presented technologically and economically.

&amp;nbsp;&amp;nbsp;In order to investigate the effects of 5th element addition to Co-29Cr-6Mo-1Ni alloys on metal ion release, Co-29Cr-6Mo-1Ni-X(X=Ti, Nb, Al, Zr) alloys were immersed in 1 mass% lactic acid solution at 37&amp;deg;C for 7 days and released metal ions were examined by ICP-AES. All of the 5th element added alloys showed less Ni ion quantities released from various alloys than that released from the original Co-29Cr-6Mo-1Ni alloy. This result suggests that Ni ion release could be suppressed by Ni-fixation mechanism due to the formation of Ni-X compounds (X=Ti, Al, Nb, Zr). Furthermore, the quantities of Co ion from Co-29Cr-6Mo-1Ni-X(X=Ti, Zr) alloys were a half less than that from the original. Each metal ion quantity released from Co-Cr-Mo-Ni alloys consisting hcp phase is lower than that from the alloys consisting fcc phase. From the relationship between microstructure and released metal ion quantity, Co-Cr-Mo-Ni alloys consisting hcp phase exhibit low released metal quantities compared to those consisting fcc phase. Therefore, it is likely that metal ion release is suppressed by controlling microstructure through the alloying method.&lt;br&gt;

The phase relations for the Ag-Pb-O system saturated with alumina and the activity coefficient of AgO0.5 in the PbO melt were investigated at 1273 K. A chemical equilibrium technique and an EMF method were applied to the measurement. In this system, there is a miscibility gap between a molten Ag-Pb alloy phase and a Pb-Ag-O oxide phase. The solubility of Ag in the oxide phase and that of Ph in the metal phase were studied as a relation of the partial oxygen pressure. These results suggest that component of silver oxide in liquid PbO phase should be represented as AgO0.5. The activity coefficient of AgO0.5 in the PbO based oxide melt at infinite dilution relative to pure solid AgO0.5 is 0.602 at 1273 K.

The phase relations for the Ag-Pb-O system saturated with alumina and the activity coefficient of AgO0.5 in the PbO melt were investigated at 1273 K. A chemical equilibrium technique and an EMF method were applied to the measurement. In this system, there is a miscibility gap between a molten Ag-Pb alloy phase and a Pb-Ag-O oxide phase. The solubility of Ag in the oxide phase and that of Ph in the metal phase were studied as a relation of the partial oxygen pressure. These results suggest that component of silver oxide in liquid PbO phase should be represented as AgO0.5. The activity coefficient of AgO0.5 in the PbO based oxide melt at infinite dilution relative to pure solid AgO0.5 is 0.602 at 1273 K.

To produce non-ferrous metals, the SO&lt;SUB&gt;2&lt;/SUB&gt; gas is also generated from the raw material such as sulfide or sulfate. A process that produces Elemental sulphur from non-ferrous smelter gas and waste plastics was investigated. &lt;BR&gt;Polyethylene was used as a deoxidizer of SO&lt;SUB&gt;2&lt;/SUB&gt; gas in the present study. The conditions for reaction of SO&lt;SUB&gt;2&lt;/SUB&gt; and polyethylene to make gas mixtures of H&lt;SUB&gt;2&lt;/SUB&gt;S and SO&lt;SUB&gt;2&lt;/SUB&gt; were calculated thermodynamically. The Claus reaction was applied to produce elemental sulphur from H&lt;SUB&gt;2&lt;/SUB&gt;S and SO&lt;SUB&gt;2&lt;/SUB&gt; gas mixture. More than 90% sulphur recovered from SO&lt;SUB&gt;2&lt;/SUB&gt; gas in small experimental furnaces used in the present study.

To produce non-ferrous metals, the SO₂ gas is also generated from the raw material such as sulfide or sulfate. A process that produces Elemental sulphur from non-ferrous smelter gas and waste plastics was investigated. <BR>Polyethylene was used as a deoxidizer of SO₂ gas in the present study. The conditions for reaction of SO₂ and polyethylene to make gas mixtures of H₂S and SO₂ were calculated thermodynamically. The Claus reaction was applied to produce elemental sulphur from H₂S and SO₂ gas mixture. More than 90% sulphur recovered from SO₂ gas in small experimental furnaces used in the present study.

ZnTe化合物の熱含量を落下型熱量計を用いて,750～1600Kの温度範囲で測定した。&lt;br&gt;熱含量-温度プロットからZnTe化合物の融点は1573±3K,融解熱は51.1±0.3kJ mol&lt;sup&gt;-1&lt;/sup&gt;と決定された。得られた熱含量値にShomate関数を適用して,固体領域の熱含量ならびに比熱の温度依存性を決定した。ZnTe化合物の生成熱および溶融Zn-Te2元系の混合熱を高温双子型熱量計を用いて測定した。溶融Zn-Te2元系合金の混合エンタルピーは化合物組成付近に近づくにつれ負の大きな値を示し,融体中に化学的な短範囲規則性が存在することが予想される。得られたZn-Te2元系合金の熱力学および従来の状態図データにAssociated Solutionモデルを適応し,モデルのパラメータを導出した。決定されたモデルのパラメータを用いて算出された熱力学諸量および状態図は,実験結果を良く再現できる。

Heat content of silicon has been measured in a temperature range of 700-1820 K using a drop calorimeter. Boron nitride was used as a sample crucible. The enthalpy of fusion and the melting point of silicon determined from the heat content-temperature plots are 48.31 +/- 0.18 kJ mol(-1) and 1687 +/- 5 K, respectively. The heat content and heat capacity equations were derived using the Shomate function for the solid region and the least square method for the liquid region, respectively, and compared with the literature values.

Emf of galvanic cells with zirconia solid electrolyte was measured to determine the activity of indium in the liquid In-Sb-Ag and In-Sb-Te systems in temperature ranges from 970 to 1280 K for the In-Sb-Ag system and for the In-Sb-Te from 870 to 1260 K. The following cells were used: Pt/Ni, NiO|ZrO&lt;SUB&gt;2&lt;/SUB&gt;(+CaO)|In-Sb-Ag, In&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt;/Re/Pt, Pt/Ni, NiO|ZrO&lt;SUB&gt;2&lt;/SUB&gt;(+CaO)|In-Sb-Te, In&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt;/Re/Pt. The isoactivity curves in the liquid In-Sb-Ag and In-Sb-Te systems at 1100 K were derived from combining the activity data of the In-Sb, In-Ag and In-Te binary alloys. The shape of isoactivity curves in the liquid In-Sb-Ag exhibits a slight bend to the Sb-Ag binary side, and those of the liquid In-Sb-Te gather from the whole composition range of the In-Sb binary alloy to the intermediate composition of the In-Te system.

The activities of indium in liquid In-Bi-Cu and In-Sb-Cu alloys have been determined by emf measurement using a zirconia electrolyte at 982&amp;sim;1259 K and 871&amp;sim;1267 K for fifteen and sixteen different compositions of the two alloy systems, respectively. Combining the binary data on In-Bi and In-Cu alloys in the In-Bi-Cu system, and In-Sb and In-Cu alloys in the In-Sb-Cu system, the isoactivity curves at 1050 and 1200 K, 1100 and 1200 K were obtained in the whole composition ranges, respectively. There seem to be no comparable published data.

A mixture of iron, copper and carbon was melted in a carbon crucible at 1, 453 K. The top layer which was rich in iron and the bottom layer which was rich in copper were clearly separated in the crucible. We could thus make fundamental experiment to carry out a phase separation for copper recovery from iron scrap containing copper. One of the focuses is the effect on the phase separation and the suspension of an extra element to the Fe-Cu-C ternary system. We added Cr, Mn, Al, Si or S to Fe-Cu-C ternary system, and determined the compositions of miscibility gap at 1, 453 K under carbon saturation. In some cases scrap contains precious metal. On this account the recovery distribution ratios of precious metal were also measured.&lt;BR&gt;The alloy compositions on the miscibility gap in the Fe-Cu-C system are 91.1% Fe-4.7% Cu-4.2%C and 96.7%Cu-3.3% Fe. Addition of aluminum, Silicon or sulfur causes the gap to narrow. An increase in carbon solubility in the phase rich in iron reduces copper solubility, which affects recovery of copper from scrap. The relation between copper and carbon solubility in the phase rich in iron is&lt;BR&gt;(% Cu)=0.68 (%C) 2-7.26 (%C) +22.77&lt;BR&gt;Gold, silver and palladium are enriched in the phase rich in copper. Platinum distributes both phases equally. The activity coefficients of Ag, Au, Pd and Pt were estimated from the distribution ratios.

A mixture of iron, copper and carbon was melted in a carbon crucible at 1, 453 K. The top layer which was rich in iron and the bottom layer which was rich in copper were clearly separated in the crucible. We could thus make fundamental experiment to carry out a phase separation for copper recovery from iron scrap containing copper. One of the focuses is the effect on the phase separation and the suspension of an extra element to the Fe-Cu-C ternary system. We added Cr, Mn, Al, Si or S to Fe-Cu-C ternary system, and determined the compositions of miscibility gap at 1, 453 K under carbon saturation. In some cases scrap contains precious metal. On this account the recovery distribution ratios of precious metal were also measured.<BR>The alloy compositions on the miscibility gap in the Fe-Cu-C system are 91.1% Fe-4.7% Cu-4.2%C and 96.7%Cu-3.3% Fe. Addition of aluminum, Silicon or sulfur causes the gap to narrow. An increase in carbon solubility in the phase rich in iron reduces copper solubility, which affects recovery of copper from scrap. The relation between copper and carbon solubility in the phase rich in iron is<BR>(% Cu)=0.68 (%C) 2-7.26 (%C) +22.77<BR>Gold, silver and palladium are enriched in the phase rich in copper. Platinum distributes both phases equally. The activity coefficients of Ag, Au, Pd and Pt were estimated from the distribution ratios.

The activities of indium in liquid In-Pb-Ag and In-Bi-Sb alloys have been determined by the emf measurement using a zirconia electrolyte at 1012&amp;sim;1263 K and 886&amp;sim;1179 K for fifteen different compositions of the two alloy systems, respectively. Combining the binary data on In-Pb and In-Ag alloys in the In-Pb-Ag system, and In-Bi and In-Sb alloys in the In-Bi-Sb system the isoactivity curves at 1100 and 1200 K, 1000 and 1100 K were obtained in the whole composition ranges, respectively. There seem no published data to be compared with.

Low temperature specific heats of the GaP, InP, GaAs and InAs compounds were measured over the temperature range 4.5 to 298.15 K using an adiabatic calorimeter. The Debye temperatures were derived from the obtained specific heat data. The curves of Debye temperature as a function of temperature for the GaP, InP, GaAs and InAs compounds exhibit a minimum in the temperature range of 15&amp;sim;30 K and a maximum at somewhat higher temparatures (approximately 130&amp;sim;180 K). The standard entropies of the GaP, InP, GaAs and InAs compounds determined from the specific heat data were 50.5, 62.1, 64.1 and 75.5 J/(mol&amp;middot;K), respectively. A relation was found between the standard entropy and the cohesive energy. The standard entropies of the III-V compounds decreased linearly with increasing cohesive energy per bond.

The activities of indium in liquid In-Bi-Ag and In-Bi-Te alloys have been determined by the emf measurement using zirconia electrolyte at 896&amp;sim;1297 K and 816&amp;sim;1111 K for 15 and 18 compositions of the alloys, respectively. Combining the binary data of In-Bi and In-Ag alloys in In-Bi-Ag system, In-Bi and In-Te alloys in In-Bi-Te system for this study, isoactivity curves at 1100 K and 1200 K. 900 K and 1000 K were obtained in the whole composition range, respectively. There seem no published data to be compared with.

The heats of formation of six III-V compounds of GaP, InP, GaAs, InAs, GaSb and InSb were determined at 773 K from the heats of dissolution of these compounds and the components in a liquid tin solvent, using a Calvet-type twin solution calorimeter. The standard heats of formation at 298.15 K, DELTAH(f,298.15)-degrees, are: GaP (P: red) - 103.2 +/- 7 kJ/mol, InP (P: red) - 70.2+/-4.4 kJ/mol, GaAs - 87.7+/-0.5 kJ/mol, InAs -60.0+/-1.0 kJ/mol, GaSb - 45.9+/-0.3 kJ/mol and InSb - 34.1+/-0.6 kJ/mol. A relation was found between the heats of formation and the bond formation energy, and the overlap interaction in the cohesive energies of these compounds. DELTAH(f,298.15)-degrees decreased linearly with increasing bond formation energy and overlap interaction energy per bond.

The heat content of the binary As-Zn and As-Cd systems were determined by a drop calorimeter in the concentration range from x(As) = 0.04 to 0.48 in the As-Zn system and in the As-Cd system from x(As) = 0.10 to 0.40. The temperature range for the zinc system was from 800 K to 1450 K and for the cadmium system from 750 K to 1250 K. The method of the thermodynamic analysis was applied to derive the other thermodynamic properties from the heat content measurements of both binary systems. In the As-Zn system the heat of mixing has a peaked minimum at approximately x(As) = 0.43 and the parabolic curve of the entropy of mixing exhibit a depression at the same composition. These strongly temperature dependent anomalies are explained by the existence of some sort of chemical short range order in the liquid. With increasing temperature these associates begin to dissociate.