Japan has the political target of creating a recycling-oriented society through 3R Activities (Reduction, Reuse, Recycling), and has already set up some recycling laws for specific products. Based on these laws and this rule-making, new recycling businesses have been created in the domestic market. The Government of Japan has targets relating to the amount of waste discharge, recycling and disposal in 2010. For example, by 2010 about 50 million more tons of waste should be recycled than at present. In order to realize these targets, additional recycling businesses are expected to be created.
However, recycling businesses need social support such as the stable collection of waste, demand-side management of recycled products, and public relations in local areas to sustain these business models.
This paper reviews the current status of recycling policy and the activities of various players, and considers the business needs for waste-recycling issues and the political aspects of creating stable recycling businesses.

View full abstract

Methane hydrates, which form at low temperature and high pressure, are found in ocean sediments and being evaluated as a potential fuel for the future. The worldwide total of methane hydrate is estimated to be equivalent to 250 trillion cubic meters of methane gas. In order to establish an efficient production technology for extraction of methane from hydrates, deformation and movement behaviour of ocean sediments have to be basically clarified. The aim of this study is to develop the low temperature auto-controlled triaxial compression apparatus and to estimate the mechanical properties by using the ice rock matrix specimen. The preliminary results on relationships between deformation properties, shear strength and sand content in the specimen are presented and discussed.

View full abstract

In the previous work, it was found that the extraction rate of Ni²⁺ with 2-ethylhexanal oxime (abbreviated as EHO) from wasted FeCl₃ etching solution was extremely slow. This is because the substitution reaction of the hydrated Ni²⁺ ions, Ni(H₂O)₆²⁺ with the extractant is a rate determining step.
In order to improve the extraction rate of Ni²⁺, the extraction rate was investigated by adding D2EHPA or TBP as a second extractant to the main extractant EHO. The big enhancement of Ni²⁺ extraction rate is found when the second extractants, D2EHPA or TBP, are added in a small amount to EHO. As an example, the addition of 0.1mol/dm³ D2EHPA and TBP results in 18 and 30 times enhancement of Ni²⁺ extraction. The extraction rate equation for Ni²⁺ is induced so as to be a reversible reaction. Then, the apparent rate constants for forward and backward reactions were calculated according to the induced rate equation. The forward extraction rate is proportional to the 1st order of Ni²⁺ concentration, TBP concentration and EHO concentration, while the backward extraction rate is proportional to the 1st order of Ni²⁺ concentration, which is written as,
-d[Ni²⁺] / dt = k_f^*[Ni²⁺]_aq [EHO]_org [TBP]_org -k_b*[Ni²⁺]_aq
The above extraction rate expression is reasonably explained by imaging the following elementary reactions and assuming the second reaction to be a rate determining step,
Ni(H₂O)₆²⁺ + TBP_ad ⇔ Ni(H₂O)₅²⁺ · TBP_ad
Ni(H₂O)₅²⁺ · TBP_ad + EHO_ad → Ni(H₂O)₅²⁺ · EHO_ad + TBP_ad

View full abstract

The precise determination of gold has be particularly required on the business transactions of blister copper. Gold is usually analysed by the Fire Assay Gravimetric (FAG) which is main traditional method. However, this method requires special facilities such as the assay crucible furnace and the muffle furnace. These facilities are exclusively used for precious metal determination such as gold. And then, Inductively Coupled Plasma- Atomic Emission Spectrometry (ICP-AES) which is commonly applied to metal analysis was studied for the determination of gold. Using high dispersive spectrometer, the coexisting elements such as Fe, Ni, Cu, Zn and Sn did not interfere with the determination of Au at the wavelength of 242.795nm. Mn gave positive error, accordingly subtraction from the Au signal was required. As the effect of aqua regia concentration was found, the amount of remained acid was measured at sample decomposition, and the amount of remained aqua regia was estimated. In order to eliminate the matrix effect the concentration of aqua regia and coexist elements between sample and standard solution for calibration were matched.
Analytical results of this proposed method extremely agreed well with that of the FAG method. The discrepancy of the proposed method from the FAG method was less than 3%. The required time for the determination was 8hrs., including the sampling and dissolution procedures.

View full abstract

During the past decade, there is a fundamental change in mining policy in many developing contries. The new role of governments as for mineral resources shifted from being both owner-opetator and referee to that of lessorregulator. Due to sucessful mining sector policy reform, such as in Chile, Peru, Argentine, Ghana, and Tanzania, these countries have increased significant amounts of foreign direct investment in mineral exploration and development activities. This paper describes the basic policy of mining legislation and taxation, and outlines the frameworks to attract private mineral investment in the countries.

View full abstract

Human being has made a bypass in the material flow in the Earth by consuming various kinds of mineral and energy resources in order to develop his activities. The environmental problems caused by the consumption indicate that the flux of the bypass has become too large to be neglected when compared with that of the natural flow. It means, accordingly, that resources and the environment are two sides of the same coin. Many mineral resources have been recycled in order to reduce the consumption and keep the environment. In contrast, energy resources, which are used for the recycling in a large quantity, cannot be recycled (Fig. 2). This implies that an appropriate amount of recycled mineral resources seems to be determined by comparing the energy resources used for supplying virgin resources and those for recycling used ones (Fig. 3). In the artificial process of material flow, money migrates contrary to materials between the resources supply and the final consumption, but parallel between consumption and waste-treatment (the upper diagram of Fig. 4). This causes illegal disposal of waste. If a guarantee system is established, money is expected to migrate also contrary to material in this part of the material flow (the lower diagram of Fig. 4). In this system, resources-supply is the most suitable point for collecting deposit tax. Many ideas are proposed for solving the carbon dioxide problem. Any of them has not been evaluated, however, from the viewpoint of the Earth's history. For example, a proposal claims that we can fix carbon dioxide in coal beds, but it has not yet shown the place where carbon dioxide generated at coalification process had gone.

View full abstract

"Earth Eco System" is essential for the sustainable development in the near future. From 2001, NEDO, Japan started the project with universities and industries on innovative ceramics absorbent material and the CO₂ recovery system for Geological Sequestration.
This material is a powdered substance named lithium silicate, a combination of lithium that easily reacts with CO₂. As the reaction formula is Li₄SiO₄ + CO₂ = Li₂SiO₃ + Li2CO3, repeated recovery and recovering of CO₂ is possible. It absorbs CO₂ at a high temperature around 500 to 600 degrees centigrade (C). The reaction heat can be recovered and reused for generation of steam and electricity. Appling effectively to industrial heat and power systems, this material may enable significant reduction of CO₂ emissions with a small energy penalty.
As 80% of the world primary energy is dependant on fossil fuel, it is essential to address large-scale emission sources to achieve the reduction targets set by the Kyoto Protocol of COP3. Even though promotion of utilizing renewable energy, energy conservation, fuel conversion to natural gas, etc. are important measures for reducing CO₂ emissions, sustained utilization of fossil fuels including coal resources cannot be denied from the viewpoint of efficient use of resources. For this reason, the implementation of an effective CO₂ recovery and sequestration system is the key to efficient use of fossil fuel for the sake of the global environment.
CO₂ separation/geological sequestration/bio-factory as the "Earth Eco System" for industrial use should be the major way to establish the sustainable energy system by using fossil fuel including coal resources for the global environment.

View full abstract

From a historical viewpoint, an abundance of mineral resources have been used in the modern era. Moreover, recently the environmental issues has been recongnized in the development of mineral resources and mining activity. Those issues are large-scale production, change of consciousness of the state, establishment of an international environmental management system and the consensus among local society, state and world society. It is needed to make a plan and implement mineral resources development based on the forecast of environmental impact, and environmental laws and regulations with consideration of the environment. In a society ideally balanced with the environment, a study of the necessary demand, proposal of substitution, request for development plan from the local society and economic evaluation feasibility study from a wide range of viewpoints are needed for the resources development.

View full abstract

The aim of this study is to quantitatively assess upcoming shortages in the supply of copper, which sustains essential socio-economic activities. This study clarifies copper shortage and depletion years through demand forecast modeling and supply potential assumptions. Copper demand models were built for industry sectors based upon GDP (gross domestic production) and population, referring to four SRES scenarios (Special Report on Emissions Scenarios) published by IPCC (Intergovernmental Panel on Climate Change). We considered the following four supply potentials: (i) resource, (ii) resource based, (iii) technological limitation based available for gold mining, and (iv) geological limitation based on crustal abundance and mining depth. The algorithms for calculating the years of shortage and depletion were as follows: (i) total copper demand scenario from 2000 to 2100 is fitted linear, (ii) the inverse slope of the linear-fitted curve is assumed for copper supply from the supply peak (i.e., year of shortage), (iii) years of the supply shortage and the depletion are calculated so that cumulative supply amount covered by the two lines plus historical production of copper before 1999 is equal to the assumed supply potentials. The total demand is forecasted at the maximum for A1 scenario and at the minimum for B1 scenario of the SRES scenario. The coming shortage years for the four SRES scenarios are (i) within 2008 and 2013 based on the resource, (ii) within 2015 and 2024 based on the resource based, and (iii) within 2047 and 2085 based on both technological and geological limitations. The depletion years are in the latter half of the 21st Century for both resource and resource based, and within the 22nd Century for both the limitation based. The afraid coming shortage of copper will be an immediate and significant problem for the next one or two decades. Depletion and shortages of copper will be coming probably during the 21st Century, even though progress in mining technologies is assumed. This implies possible threats to sustainable development are coming from demand/supply of copper as well as global warming.

View full abstract