Maeng-Eon Park

Economic and environmental applications for recent innovations of nonferrous metallurgy in some industrial nations

As ore grades drop at today’s large mines, and environmental regulations for waste discharges increase, economics drives new recovery innovations. This paper describes some technological advances in the recovery processes for copper, gold, silver, lead and zinc. It does not discuss pyrometallurgy. Korea, like many nations with industrial economies, consumes large amounts of these metals, and is dependent on overseas suppliers for nearly its entire supply. This paper also discusses how technology for recovery of metal now in Korea, for example from existing wastes, is important. Improved reagents for both leaching and froth flotation of copper minerals, plus bio-oxidation and pressure autoclaving for gold have improved metal recovery. Copper recovery by SX-EW is expanding rapidly, and the method is also commercial for zinc. Biooxidation of encapsulating waste materials and, in some instances, of the desired metal has reached commercial scale. Pressure leaching on a large scale solves specific problems for several metals. Improvements in gold and silver cyanidation include variants of activated carbon adsorption from solution. Zinc and lead still largely depend on flotation for the treatment of ores. However, innovation in hydrometallurgical extraction has been spurred by environmental concerns. Computer modeling and process control worldwide have likely led to the largest improvements in recovery. The limited availability of land, clean water and sites for waste disposal in many countries affects the economics of re-treatment of existing wastes. Some of the new technologies could be combined, for example in modular plants that can be moved between reclamation sites to economic advantage on the Korean Peninsula.

New discoveries, skarn zonation, and skarn textures at the Geodo Mine in the Taebaeksan Basin, South Korea

The Geodo skarn deposit is located in the Taebaeksan Basin, central eastern Korean Peninsula. The geology of the deposit consists of Cambrian to Ordovician calcareous sedimentary rocks and the Cretaceous Eopyeong granitoids. The skarns at Geodo occur around the Eopyeong granitoids, which consist, from early to late, of magnetite-bearing equigranular quartz monzodiorite, granodiorite, and dykes. These dykes emanated randomly from equigranular granodiorite and some of dykes spatially accompany skarns. Skarn Fe mineralization, referred as Prospect I and II in this study, is newly discovered beyond previously known skarns adjacent to the quartz monzodiorite. These discoveries show a vertical and lateral variation of skarn facies, grading from massive reddish-brown garnet-quartz in a lower and proximal zone to banded in an upper and distal zone, reflecting changes in lithofacies of the host rocks. Skarn veins in distal locations are parallel to sedimentary laminae, suggesting that lithologic control is important although proximal skarn has totally obliterated primary structures, due to intense retrograde alteration. Skarns at Geodo are systematically zoned relative to the causative dykes. Skarn zonation comprises proximal garnet, distal pyroxene, and vesuvianite (only in Prospect I) at the contact between skarn and marble. Retrograde alteration is intensely developed adjacent to the contact with dykes and occurs as modification of the pre-existing assemblages and progressive destruction such as brecciation of the prograde assemblages. The retrograde alteration assemblages consist predominantly of epidote, K-feldspar, amphibole, chlorite, and calcite. Most of the magnetite (the main ore mineral), replaces calc-silicate minerals such as garnet in the lower proximal exoskarn, whereas it occurs massive in distal pyroxene and amphibole in the upper and distal exoskarn. The emanation of dykes from the equigranular granodiorite has provided channelways for ascent of skarn-forming fluids from a deep source, whereas the style and nature of skarns suggest that originally structurally-controlled skarn-forming fluids may migrate long distances laterally to produce skarn in calcareous sedimentary rocks.

Standardization Studies for the Oriental Mineral Medicine

Oriental mineral medicines are single or mixture of more than one mineral species or rock/fossil which are used to treat disease. Mineral medicines remove harmful or useless substances to decrease toxicity and secondary effects, and cause the manufacture of medical compounds with increased efficacy. The extraction test is an accepted in vitro system to predict the bioaccessibility of major and minor elements from mineral medicine. It incorporates gastrointerstinal tract parameters representative of a human body that including stomach and small intestinal pH which are the same as digestion condition. The bioaccessibility of a mineral medicine is the fraction that is soluble in the gastrointestinal environment and is available for absorption. Reaction path modeling in the human body can predict digestion with gastric fluid as well as absorption in the small intestine, existence in body fluids and reaction progress of the exhaust process according to pH conditions in body. Also reaction path modeling can predict bioavailability, which is equal to existence rate in the body and the form and amount of a medicine in the body after intake. The study results from predicating the existence form mineral medicines in the body, and proving the effective ingredient using bioaccessibitily and human risk assessment, suggest these that should be necessary data for new medicine development.

A Mineralogical and Gemological Studies for the Enhancement of Tanzania Ruby by Heat Treatment

Department of Earth Environmental Science, Pukyong National UniversityRuby is one of the most favor colored gem, for beautiful red tone, be high in scarcity value. However, rubieswith high quality are produced in restricted regions, such as in Thailand, Sri Lanka, Myanmar, and Tanzania etc.,and they have been gradually exhausted by mining for a long period. Therefore, improving qualities of low levelrubies with various treatments is arising an alternative way to obtain better rubies. Gemological and mineralogicalproperties of the natural ruby from Tanzanian were studied with heat treatments. Those characteristics were com-pared between only heat and adding flux materials under heating. Tanzanian raw rubies were applied a heat treat-ment (1,600°C for 6 hours). However, chromameter and UV-Vis analyses found that a simple heat treatment isinappropriated for the Tanzanian ruby. Although Cr