Special Issue

Computer Aided Studies of Resources and Material Developments in NIRE

Review

Computer Simulation and Analysis of the Multistage Solvent Extraction Processes for Metal Ions

Mikiya TANAKA (Rare Metals Div., Materials Processing Dept., NIRE)

Abstract

Metal solvent extraction in industry is usually operated on the basis of a multistage process. Since many operational parameters affect the performance of the multistage process, computer simulation plays an important role to assess these effects. This article consists of the following four topics describing our recent work on this field: (i) Simulation of the countercurrent multistage extraction - stripping process, (ii) analysis of the simulation results in terms of the steady-state local linearization, (iii) proposal of a new simulation method based on the steady-state local linearization, and (iv) simulation of the multistage separation and recovery of copper and nickel from ammoniacal alkaline solutions.

Key words: Solvent extraction, Computer simulation, Multistage process, Steady-state local linearization

(Language:Japanese)

Review

Distinct Element Method - Virtual Experimentation of Solids Mixing

János SZÉPVÖLGYI and Shigehisa ENDOH (Materials Handling and Characterzation Div.,Materials Processing Dept., NIRE)

Abstract

The three-dimensional motion of individual particles in batch gravity mixer tubes equipped with Kenics-type static mixer elements was simulated by numerical methods. The particle-particle and particle-wall interactions are modeled by the Cundall's model [1], which expresses the contact forces by a spring, a dash-pot and a friction slider. The influence of the various construction parameters on the achievable homogeneity and on the efficiency of the mixer was investigated. The results of particular simulation are in good agreement with the experimental findings.

Key words: Simulation, Distinct Element Method, Cundall's Model, Particle Mixing,Static Numerical Simulation Mixer

(Language:English)

Review

Simulation of Material Processing under Extreme Conditions
- Analysis of Plasma Flow Field -

Masami SUGASAWA and Nobuyuki KIKUKAWA (Siliceous Materials Div., Materials Processing Dept., NIRE)

Abstract

Thermal plasma is defined as a hot gas in which total electric charge of ions and electrons generated by ionization is neutral, and Local Thermodynamic Equibrium ( LTE ) is maintained over the majority of plasma core. Since 1960s, synthesis of materials (ultrafine particles or thin films) using thermal plasma has been studied actively. Because of the quenching effect due to drastic temperature decrease, material synthesis process by thermal plasma has a possibility to produce compounds having stoichiometries or crystal phases which cannot be produced by ordinary thermal chemical reactions. Furthermore, the high velocity of plasma flow generates the advantage of rapid material synthesis, compared with other gas or liquid phase methods. However, many problems such as enormous electric power consumption and quantity limitations of raw materials supplied to plasma ascribed to plasma unstaibility etc. exist in the process. To solve these problems and to better synthesize objective materials, it is necessary to analyse and control the plasma physical properties such as velocity, temperature and chemical species distributions. Moreover, to optimize the synthesis process of ultrafine particles or thin films, nucleation and particle growth in plasma tail flame should also be analysed. Therefore, in this review, we examine previous modelling studies on above-mentioned topics comprehensively, and search for the problems which must be solved in the future.

Key words: Plasma flow field, Nucleation, Particle growth, Modelling

(Language:Japanese)

Review

Numerical analysis of plasma momentum and heat transfer toentrained particles - A review

Kandasamy RAMACHANDRAN and Nobuyuki KIKUKAWA (Siliceous Materials Div., Materials Processing Dept., NIRE)

Abstract

Plasma heating has been using for variety of materials processing. Since complex nature of the plasma and many process parameters are incorporated in the plasma heating process, controlling of the process is being difficult. It is felt that the fundamental understanding of the process is needed to overcome this problem. In order to understand the basic physics involved in the plasma heating process, researchers are stimulated to develop numerical modeling on the same. Numbers of papers have been published on plasma - particle interaction with various aspects. In this article, modeling and simulation of heat, mass and momentum transfer from plasma flow to entrained material particles which are used for processes of plasma spraying, fine particle synthesis and waste treatment are reviewed.

Key words: Thermal plasma, Heat and mass transfer, Internal heat conducton, Particle momentum transfer

(Language:English)

Review

Material Diagnosis
- Simulation of flaw detection by ultrasonic wave -

Takahiro HAYASHI (Materials Handling and Characterization Div., Materials Processing Dept., NIRE)

Abstract

Ultrasonic is widely used for nondestructive testing (NDT) for materials. Simulation of ultrasonic propagation, which is useful and helpful for newly developed ultrasonic NDT, is summarized in this report. The outline of conventional and general simulation technique such as Finite Differential Method, Finite Element Method and Boundary Element Method is presented. Moreover the state-of-the-art technique on Lamb wave simulation that is difficult to be done by the conventional ones is introduced.

Key words: Ultrasonic Nondestructive Testing, Simulation, Lamb wave

(Language:Japanese)

Review

Estimation of resource cycling system

Hitoshi OHYA, Shigehisa ENDOH (Materials Handling and Characterization Div., Materials Processing Dept., NIRE)
Atsushi INABA (Emergy Analysis Div., Energy Resources Dept., NIRE)

Abstract

Recycling is important for the global environment, however, it is very difficult to determine the environmental load. One of the most popular and typical methods is a life cycle assessment. Some of the examples are reviewed in this paper.

All of our activities have been developed to obtain a high exergy material and/or energy and throw away the waste and/or waste heat. We are trying to use exergy to estimate the quantity of energy and matter for resource accounting. The environmental assessment of recycling was possible using this method. The exergy reduction of the entire system, which is estimated by the yield of matter and the process efficiency, is important when considering the global environmental load.

Key words: Recycling, LCA, Exergy Analysis

(Language:Japanese)