The use of pig iron and the resulting formation of liquid iron base alloys from the solid ones at medium temperatures in nonferrous metallurgy will be of great interest for developing new processes to treat solid iron base alloys containing arsenic or antimony such as furnace residues and secondary Fe-Cu alloys produced in reducing smelting and recycling. In this report, some fundamental data on the phase relations and distribution of minor elements between the liquid iron base alloy (pig iron) and coexisting liquid phases in the Fe-Pb-C-M (M = As, Sb), Fe-Cu-C-M and Fe-Cu-S-C-M systems saturated with carbon at 1200°C are summarized. Based on these data, materials-balance calculations were made on some processes using pig iron, which have been proposed by the authors, focusing on the elimination or fixation of arsenic and antimony and the recovery of valuable elements when the Fe-Pb composite byproduct produced in lead smelting, the Fe-Cu furnace residue recovered in copper smelting and recycling, and the copper matte recovered in slag cleaning are treated.
In this paper, China's policy on non-ferrous metals is analyzed. China is one of the largest producers and consumers of non-ferrous metals. Especially, it is the largest producer of many kinds of rare metals including rare earths, tungsten and indium. Since Japan heavily depends on China for these metals which are indispensable for high-tech applications, any change in China's policy on metals is likely to affect Japan's manufacturing industries and economy as a whole. Official Chinese documents including Five-Year Plan seem to show that China has two types of metal policy. One is to ensure a stable supply of base metals as their supply-demand situation is getting tighter. To this end, China encourages foreign companies to take part in the development of base metal mines in China, and also encourages Chinese companies to acquire greater amount of metals from abroad. The other is to control production and export of some rare metals. It appears that China aims to make its domestic industry more value-added by limiting outflows of raw materials. Measures such as export quotas and export taxes seem to be taken by China toward this end. The policy above will have a strong impact on metal supply as well as metal prices. This is particularly true for several rare metals that China almost dominates the world market in. Given these circumstances, Japan has to work hard to ensure a stable supply of rare metals. The actions we need to take include diversification of metal sources, recycling, R&D activities for material substitution, and close dialogue with China. Also, further examination will be needed as to the consistency of China's export control with the WTO.
Kushiro Coal Mine in Kushiro, Japan is now excavating coal seams at a shallower level than before. Approximately 100 old workings, which were excavated about 50 years ago, were observed at either longwall coal faces or sidewalls of roadways. Most of them were completely closed with a few exceptions, which were in open condition without severe deformation. Two thirds of the observed old workings were closed mainly by roof sagging. The sagged roofs were either deflected or plugged in. Development of the tension cracks were observed in the deflected roof. One third of the old workings were closed mainly by floor heaving, mostly accompanied by the severe deflection. Complete closure of the old workings can be attributed to the following two reasons: One is rock stress of considerable magnitude composed from the initial one and the induced one due to mining. Another is weakening of the sedimentary rocks surrounding the opening due to increase of the water content brought mainly by the supply of water detached from the injected filling material with high water content. It is certain that the two mechanisms work simultaneously to the closure of the old workings, but the latter is considered to be prior to the former in its effect.
In-situ measurements were conducted at closed old roadways in Kushiro Coal Mine in Kushiro, Japan. Based on the results of the P-wave velocity and permeability obtained at the closed old roadways, the material comprising deformed rock mass, filler, plastically deformed clay and softened rocks, with which the closed old roadways are filled, is judged to have the same quality with that of weak rock mass. This nature could be brought by the stress of small magnitude which has loaded the closed old roadways. In-situ monitoring of stress induced in the longwall goaf revealed that the crushed rocks in goaf have been receiving stress of fair magnitude, which could bring their consolidation. This anticipation was confirmed by the observation of the closed old goaf abandoned about 52 years ago that the crushed rocks have been consolidated to such extent that the machining surface created by the drum shearer is smooth and self supported. A suggestion was proposed for reasonable design and construction of rock caverns which could maintain mechanical stability for a long time in such sedimentary rock masses as ones encountered in Kushiro Coal Mine.
Buildings are often damaged by earthquake and land sinkage. Moreover, in Japan, concrete constructions built during the period of high economic growth are getting old. On the other hand, due to weather and geographical features, the collapse of rock slope occurs in many places. So, authors have been conducting a study of the safety assessment of concrete constructions and rock slope using reflection wave method. In this study, the giant-magnetostriction vibrator was used as a transducer to input the ultrasonic wave into a concrete block. Giant-magnetostriction vibrators have much greater input power than piezo-electric ceramics. So, the safety assessment of large scale objects that do not respond with piezo-electric ceramics is possible. These researches are generally called "Non-destructive testing" and herculean task due to the influence of direct wave, because the output wave contains a wave with direct wave and reflection wave together. In this study, as the method to detect the reflection wave, cepstrum analysis was adopted, and arrival times of reflection waves from the bottom of concrete block are shown. The result of cepstrum analysis is greatly influenced by the noise. To improve the result of analysis, the window function which is used in the process of cepustrum analysis was focused, and reduced the influence of direct wave using input voltage waveform. Moreover, the addition of the results of cepstrum analyses in different frequency was applied and the result was greatly improved. The result of this research shows that the cepstrum analysis with giant-magnetostriction vibrator for non-destructive testing is available.
CO2 capture and storage (CCS) is one of expected methods to reduce its emissions into the atmosphere. The Japan consortium to proceed the CO2 sequestration into coal seams has carried out a project on CO2 injection at Yuhbari City, Hokkaido. A targeted coal seam at Yuhbari is located about 1,000m below the surface. However, supercritical condition of CO2 has not been set up due to heat loss along the deep injection tubing. The absolute pressure at the bottom hole is approximately 15.5MPa and the CO2 temperature is about 28°C before the injecting into coal seam. Therefore, it can be assumed that CO2 is injected in liquid phase to the coal seams. Replacements of usual tubing with thermal insulated tubing were carried out, however, the temperature at the bottom hole was still lower than the CO2 critical temperature. The liquid CO2 causes decreasing injectivity into the coal seam due to high viscosity and swelling of the coal matrix. This study has provided a numerical procedure to predict the CO2 characteristics includes a phase change (supercritical or liquid) in considering heat transfer from the injector to surrounding casings and strata. Present study has focused on the feasibility of supercritical CO2 injection because viscosity of supercritical CO2 is 40% smaller than that of liquid CO2. Present predictions on CO2 temperature at the bottom hole have been matched with measurement results by the wire line test. We have successfully predicted CO2 temperature in order to keep CO2 in supercritical conditions from the surface to the bottom for various CO2 injection rate and electric heater power to keep CO2 temperature. Finally, the minimum CO2 injection rates have been presented as 12 ton/day without a heater and 11 ton/day with heating by 1.43kW heater respectively for a model using the thermal insulated tubing.
Photochemical oxidations reactions of phosphite ions in the presence and absence of H2O2 as well as TiO2 catalyst were studied in order to develop a simple and efficient process for the treatment of spent liquor containing phosphite ions of electroless plating. The principal results obtained are as follows: (1) Aqueous phosphite ions were oxidized to phosphate ions by dissolved oxygen under UV irradiation, showing an initial induction period. Their oxidation rate became quickly high in alkaline solution, slowing down in the order of acidic and neutral. The concentration of dissolved oxygen affected the oxidation rate in an alkaline solution, but no distinct effect was detectable in the acidic range; (2) the oxidation of phosphite ions proceeded by the addition of H2O2 under UV irradiation; (3) the oxidation reaction of phosphite ions was greatly enhanced by UV irradiation in the presence of TiO2 catalyst, and the induction period disappeared. The dependency of pH for both the oxidation rate and amount of phosphite ions absorbed onto TiO2 catalyst showed a similar tendency, indicating that the adsorption of phosphite ions onto the TiO2 catalyst played an important role in the photocatalytic oxidation of phosphite ions; (4) other factors, such as the TiO2 amount and UV irradiation intensity, were also examined.