• Resources Recycling
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• v.28 no.5
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• pp.30-41
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• 2019

Global production of zinc is about 13 million tons and zinc is the fourth-most widely used primary metal in the world following iron, aluminum and copper. When zinc is recycled to produce secondary zinc, it can save about 75 % of the total energy that is needed to produce the primary zinc from ore, and in therms of $CO_2$ emissions reduced by about 40 %. However, since zinc is mainly used for galvanizing of steel, the recycling rate of zinc is about 25 %, which is lower than other metals. The raw materials for recycling of zinc include dusts generated in the production of steel and brass, sludge in the production process of non-ferrous metals, dross in the melting of zinc ingots or hot dip galvanizing, waste batteries, and metallic scrap. Among them, steelmaking dust and waste batteries are most actively recycled up to now. Most of the recycling process uses pyrometallurgical methods. Recently, however, much attention has been given to a combined process of pyrometallurgical and hydrometallurgical processes.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1488-1491
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• 1996

Throughout CGL(Continuous Galvanizing Line) in steel works, zinc-coated steel sheets are produced which are used where long-running corrosion resistivity is required. During the galvanizing process, top dross is created and floated on the zinc pot. Because the dross leaves ill patterns on the coated sheets, it is removed manually with shovel-like tools in about twenty minutes. Because, however, the working environment is very noisy, hot and harmful to human workers, a robot system is developed and implemented on a real plant to automatically remove the top dross. It consists of a robot and its carriage system, a pot level sensor, a system controller, and special tools to collect, pick up, and put the top dross into a dross waste basket. A system software is developed to monitor the system status. A series of tests were performed to verify the robot motion and adaptation to working conditions, and proved successful work.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.18 no.2
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• pp.99-107
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• 2008

We quantified the human carcinogenic metals (chromium, nickel) in fumes from flux cored arc welding using stainless steel (FCAW/SS) wires. Zinc and calcium were also quantified because of their possibility of zinc chromate and calcium chromate, respectively. Welding was performed in an American Welding Society standard fume collection chamber. Insoluble and soluble forms of metals were analyzed by ISO 15202 method. Total chromium (insoluble+soluble) content and total nickel content were lower in FCAW/SS fumes (4.65%, 1.05%, respectively)than in stainless steel content (ca. 18%, 8%,respectively). Insoluble fraction in total chromium was 79.8 (range 64.5~95.1)% and 94.4(range 90.1~98.1)% in total nickel. Atomic emission spectroscopy used in this study does not differentiate the chromium valence status while ACGIH defines its carcinogenicity according to the valence status. From this study and previous study, we estimated the hexavalent chromium content in FCAW/SS was 0.2~1.1% and about 85% of them was soluble. The content of zinc and calcium, which can be existed as chromate forms, was low (0.02 %, 0.04% respectively) in FCAW/SS. Exposure assessment for zinc chromate and calcium chromate is possible because chromium in both compounds is used as a surrogate even though it is not well known that what compounds of zinc and calcium are formed in welding fume.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1433-1437
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• 2007

Two field trials were carried out to evaluate the performance of a soluble glass copper, cobalt and selenium bolus for maintaining adequate levels of the three trace elements in yaks. Forty yaks were used in trial 1 and 60 yaks were used in trial 2. In each trial two commercial soluble glass boluses were administered to half of the yaks. Blood samples were taken from the jugular vein at day 0, 30, 60, 90 in trial 1 and at day 0, 45, 75 and 105 in trial 2. The samples were analysed for copper status (serum caeruloplasmin activity and copper concentration), cobalt status (serum vitamin $B_{12}$ concentration and cobalt concentration), selenium status (erythrocyte glutathione peroxidase activity and selenium concentration) and serum zinc concentration. The erythrocyte glutathione peroxidase activities, serum caeruloplasmin activities and serum vitamin $B_{12}$ concentrations for trial 1 and 2 were all significantly increased for the bolused yaks (p<0.001 or p<0.01) on all sampling days. The bolused yaks had a significantly higher selenium and copper status in serum than the control yaks on all sampling days in trial 1 and 2 (p<0.05 or p<0.01). There were no significant differences in zinc and cobalt concentrations between the bolused yaks and the controls.

• Journal of the Korean Dietetic Association
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• v.12 no.4
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• pp.378-389
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• 2006

The purpose of this study was to investigate the status of magnesium, iron, copper and zinc nutrition in 28 normal and 28 obese male elementary school students who have over 30% obesity index. The anthropometric measurements, dietary intakes and serum levels of magnesium, iron, copper and zinc were determined by 24-hr recall method and blood analysis, respectively. The mean age, height, weight, and obesity index were 10.9years, 147.4cm, 61.1kg, and 50.5% in obese group and 10.8years, 145.4cm, 40.2kg, and 3.3% in normal group. There was no significant difference in average daily food intake between obese and normal group, but meats(p＜0.05) intake of obese group was significantly lower than that of normal group. The intakes of energy, magnesium, iron, copper were not significantly difference between obese and normal group, but heme iron(p＜0.05) intake of obese group was significantly lower than that of normal group. Zinc(p＜0.05) intake of obese group was significantly higher than that of normal group. Serum magnesium(p＜0.001) level of obese group was significantly higher than that of normal group, but there were no significant differences in serum iron, copper, zinc levels between obese and normal group. There was a significantly positive correlation between serum magnesium and weight(p＜0.05), and obesity index(p＜0.05). There was a significantly positive correlation between serum magnesium and energy intake(p＜0.05), protein intake(p＜0.05), animal protein intake(p＜0.05), phosphorus intake(p＜0.05) and animal iron intake(p＜0.05). There was a significantly positive correlation between serum magnesium and seaweeds intake(p＜0.05), milks intake(p＜0.001). Also, there was significantly positive correlation between serum copper and oils and fat intake(p＜0.05). These results suggest that there should be careful considerations for micronutrients nutrition status among male obese elementary school students.

• Journal of Nutrition and Health
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• v.51 no.2
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• pp.121-131
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• 2018

Purpose: This study was aimed to assess selenium and zinc status in female collegiate athletes and their relationship with dietary intake. Methods: Female collegiate athletic groups of judo and aerobics, and healthy sedentary collegiate females were recruited for this study and their serum selenium and zinc contents were measured by the neutron activation analysis (NAA) method. In addition, the dietary intake of subjects was measured using the two days 24-hour recall method. Results: Serum selenium in judo athletes was $10.7{\mu}g/dl$, which was significantly lower than that of aerobic athletes ($12.2{\mu}g/dl$), but not different from that of the sedentary group ($11.4{\mu}g/dl$). Additionally, serum zinc levels were $96.1{\mu}g/dl$ and $90.2{\mu}g/dl$ in aerobic and judo athletes, respectively, which did not differ significantly. Moreover, dietary selenium and zinc intake of the athletic groups did not differ significantly from that of the sedentary female group. Overall, 33.3% of the serum selenium concentration variation was explained by the intake of vitamin E, selenium and saturated fatty acids, while 14.7% of the serum zinc level variation was explained by the intake of saturated fatty acids. The strongest dietary indicator for serum selenium and zinc levels was saturated fatty acids intake. Conclusion: Judo athletes appear to have lower selenium status than aerobic athletes, suggesting different body selenium status according to sport type. To maintain body selenium and zinc levels, the dietary intake of saturated fatty acids should be decreased.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.515-518
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• 2003

Six mature purebred Angus cows ($3.5{\pm}1.5$ years of age, $631.36{\pm}8.63kg$), three pregnant ($250{\pm}7$ days pregnant) and three non-pregnant and eight mature Suffolk ewes ($5{\pm}1.2$ years of age, $68.18{\pm}2.3kg$) four pregnant $115{\pm}5$ days pregnant) and four nonpregnant were utilized in a five-day metabolic trial to determine the effects of gestational status (pregnant vs. non-pregnant) on apparent absorption and retention of copper (Cu) and zinc (Zn). Animals were selected based on body weight, age, and gestational status, and randomly assigned to metabolic crates for total fecal and urine collection. Animals were allowed to acclimate to their new environment for seven days. Pregnant and non-pregnant cows and ewes were then paired (within a species) by body weight and pair-fed throughout the 5 day collection period. Copper and Zn intakes were similar for pregnant and non-pregnant animals within a species. Apparent absorption of Cu (p<0.06) and Zn (p<0.04) were higher in pregnant cows relative to non-pregnant cows. Pregnant cows also had a higher apparent retention of Cu (p<0.05) and Zn (p<0.06) relative to non-pregnant cows. Pregnant ewes had a higher (p<0.01) apparent absorption and retention of Zn compared to non-pregnant ewes. However, apparent absorption and retention of Cu were similar for pregnant and non-pregnant ewes. These data indicate that certain physiological and/or metabolic parameters are altered in pregnant cows and ewes consuming an alfalfa-based diet that enhance the apparent absorption and retention of certain trace minerals.

• Journal of Nutrition and Health
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• v.38 no.7
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• pp.578-585
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• 2005

Maternal zinc deficiency is relatively common worldwide, but its consequences for pregnancy outcome are not established. The purpose of this study was to examine the effect of zinc status in the second trimester on pregnancy outcome. Subjects were 248 pregnant Korean women (25-28 wk gestation). Cord blood was collected from subgroup of 69 women and pregnancy outcome data were obtained from 185 babies. Anthropometry measurement, dietary intake, and biochemical characteristics of pregnancy and cord serum substances were measured. The subjects were divided into quartiles on the basis of maternal serum Zn concentration; $ZnQ_1$ (< 25 percentile), $ZnQ_2$ ($26\~50$ percentile), $ZnQ_3$ ($51\~75$ percentile), and $ZnQ_4$ ($76\~100$ percentile). Zn groups were compared in terms of various maternal factors, concentrations of cord serum substances, and pregnancy outcome. Maternal serum Zn concentration was $118.4\;{\pm}\;35.5\;{\mu}g/dl$ as mean. Intake of Zn was lower than Korean RDA. The rate of Zn deficiency among all subjects was $8.5\%$. Maternal serum Zn levels belonged to normal range. Cord serum Zn level was about $154.7\%$ of maternal serum level. Intakes of energy, calcium, iron, folic acid, and riboflavin did not meet the Korean RDA for pregnant women by gestational age. The mean birth weight of neonates is 3083 $\pm$ 697 g, of whom $9.1\%$ were of low birth weight (< 2,500 g). Maternal serum Zn level was positively correlated with pre-pregnancy weight, pre-pregnancy body mass index, and vitamin C intake (p < 0.05). $ZnQ_1$ group had significantly lower maternal serum iron concentration and higher cord serum cholesterol than those in other groups. Maternal serum Zn level, cord serum Zn level, and dietary Zn intake were no related to the pregnancy outcome. The birth weight had a correlation with the maternal hemoglobin and albumin concentration. In conclusion, at this study, we could not find the association with maternal Zn status in 2nd trimester and pregnancy outcome.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.4
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• pp.579-584
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• 1999

The trace mineral status of cattle in the smallholder grazing areas of Sanyati and Chinamhora in Zimbabwe was evaluated during the rainy and dry seasons of 1994 and 1995. The evaluation was done in terms of mineral concentration in blood plasma. Plasma copper in calves, steers and cows in the dry season was; Sanyati: 0.55, 0.59, and 0.61; Chinamhora: 0.59, 0.58, and $0.60{\mu}g/ml$, respectively versus a normal of $0.65{\mu}g/ml$. In the rainy season, copper was deficient at both sites (averaging $0.56{\mu}g/ml$ and $0.59{\mu}g/ml$ at Sanyati and Chinamhora, respectively). Plasma selenium in the dry season was 0.017, 0.025, and $0.017{\mu}g/ml$ for calves, steers and cows, respectively at Sanyati versus a normal of $0.03{\mu}g/ml$ and therefore considered to be deficient. Iron, zinc and cobalt were found to be generally high and therefore unlikely to be deficient. Copper and selenium are recommended in salt licks in these environments.

• Korean Journal of Veterinary Research
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• v.27 no.2
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• pp.361-383
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• 1987

This thesis was designed to find out whether the cadmium content of hair in living animals reflects the status of cadmium accumulation in internal organs or muscles so that this status can be used as a diagnostic method. Forty-five rats were divided into 4 experimental groups and one control group. The control group received a basal diet which contained zinc $100{\mu}g/g$, iron $80{\mu}g/g$ and copper $135{\mu}g/g$. The experimental group received experimental diets sllpplemented with 1, 10, 100 or $1,000{\mu}g/g$ cadmium as cadmium sulfate. Rats were dissected on the 28th or 56th day of experimental periods and tissues, blood and hair samples were taken, dried and burned to ash and analysed. The cadmium, iron zinc and copper concentrations were measured with an atomic absorption spectrophotometer. In addition feed efficiency and hematological changes were observed. The results obtained can be summerized as follows: A marked decrease in feed intake, weight gain and feed efficiency were observed from 1 or 2 weeks of experimental periods, which was in accordance with the dosage and periods. The cadmium contents of kidney, liver, spleen and muscle were significantly increased in all experimental rats; the accumulation was marked in kidney and liver tissues. It was shown that the cadmium contents of hair reflects the cadmium accumulation in internal organs and muscle; the higher the cadmium levels of diet and of rat tissues, the higher the cadmium content of hair. In the $100{\mu}g/g$ group of rats erythrocyte counts and. hemoglobin concentrations were decreased. A significant(p<0.01, p<0.05) increase in iron contents of kidney, liver and muscle was observed in 10, 100, $1,000{\mu}g/g$ groups of rats on the 28th day of experiment. A significant (p<0.01, p<0.05) increase in zinc contents of kidney, liver and muscle was observed in all experimental rats. On the other hand, serum zinc concentration was decreased. A significant(p<0.01) increase in copper contents in the liver was observed on the 28th day in $100{\mu}g/g$ and $1,000{\mu}g/g$ groups of rats. From these results it may be concluded that the analysis of hair for cadmium is a useful diagnostic approach for the cadmium status of internal organs and muscle in living animals.