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At least 19 recordsLinked to original sources
PubMed2005

Emission of PCDD/Fs and dioxin-like PCBs from metallurgy industries in S. Korea.

The metallurgy industry and municipal waste incinerators are considered the main sources of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in many countries. This study investigated the emission factors and total emissions of PCDD/Fs and dioxin-like polychlorinated biphenyls (PCBs) emitted from metallurgy industries (including ferrous and nonferrous foundries) in Korea. The toxic equivalency (TEQ) emission factor of PCDD/Fs was the highest for secondary copper production, at 24451 ng I-TEQ/ton. The total estimated emissions of PCDD/Fs from these sources were 35.259 g I-TEQ/yr, comprising 0.088 g I-TEQ/yr from ferrous foundries, 31.713 g I-TEQ/yr from copper production, 1.716 g I-TEQ/yr from lead production, 0.111 g I-TEQ/yr from zinc production, and 1.631 g I-TEQ/yr from aluminum production. The total estimated annual amounts of dioxin-like PCBs emitted from these sources were 13.260 g WHO-TEQ/yr, comprising 0.014 g WHO-TEQ/yr from ferrous foundries, 12.675 g WHO-TEQ/yr from copper production, 0.170 g WHO-TEQ/yr from lead production, 0.017 g WHO-TEQ/yr from zinc production, and 0.384 g WHO-TEQ/yr from aluminum production. The highest emission factor was found for secondary copper smelting, at 9770 ng WHO-TEQ/ton.

Air Pollutants↗
PubMed2002

The influence of metallurgy on the formation of welding aerosols.

Recent research has indicated that insoluble ultrafine aerosols (ie., particles whose physical diameters are less than 100 nm) may cause adverse health effects due to their small size, and that toxicological response may be more appropriately represented by particle number or particle surface area. Unfortunately, current exposure criteria and the associated air-sampling techniques are primarily mass-based. Welding processes are high-temperature operations that generate substantial number concentrations of ultrafine aerosols. Welding aerosols are formed primarily through the nucleation of metal vapors followed by competing growth mechanisms such as coagulation and condensation. Experimental results and mathematical tools are presented to illustrate how welding metallurgy influences the chemical aspects and dynamic processes that initiate and evolve the resultant aerosol. This research suggests that a fundamental understanding of metallurgy and aerosol physics can be exploited to suppress the formation of undesirable chemical species as well as the amount of aerosol generated during a welding process.

Aerosols↗
PubMed1987

[Heavy metal exposure of the population in an area of nonferrous metallurgy--a prerequisite for the development of atherosclerotic diseases].

A survey is carried out among the population of a district with nonferrous metallurgy in view of studying the mutual relation between the exposure to heavy metals and some basic risk factors for the development of ischemic disease of the heart. The study pertains to the content of lead, cadmium, copper and zinc in blood and its relation to the serum lipids, glutathione in blood, arterial pressure and age. A higher level of triglycerides and free butyric acids were established in the serum with absence of clinical manifestations as a result of exposure to heavy metals. A significant correlation of cadmium, copper and zinc with serum lipids was found. On the basis of regressive analysis equations for the changes in the biochemical indices are derived under the effect of exposure to heavy metals, as well as for the connection of the arterial pressure with age and serum cholesterol. It is reckon that in clinical healthy young people under the effect of nonoccupational exposure to heavy metals a prerequisite is created for development of atherosclerotic diseases in mature and advanced age. It is recommended that the environmental pollution by nonferrous metallurgy to be accepted as risk factor for development of ischemic disease of the heart and to be taken under consideration in the complex preventive measure for this disease.

Adult↗
PubMed2005

Leaching of APC residues from secondary Pb metallurgy using single extraction tests: the mineralogical and the geochemical approach.

Two air-pollution-control (APC) residues--one from flue gas cooling with alkaline water and one from deionized water cooling--from secondary lead metallurgy were submitted to two different standardized short-term leaching protocols: US EPA toxicity characteristic leaching procedure (TCLP) and static leaching according to Czech/European norm EN 12457-2. The experimental procedure was coupled with detailed mineralogical investigation of the solid material (SEM, XRPD) and speciation-solubility calculations using the PHREEQC-2 geochemical code. Both types of residues were considered as hazardous materials exhibiting substantial leaching of Pb (up to 7130 mg/l) and other inorganic contaminants. However, the APC residue produced by flue gas cooling with alkaline water (sample B) exhibits more favourable leaching and environmental characteristics than that produced by simple deionised water cooling (sample A). At pH < 5, primary caracolite (Na3Pb2(SO4)3Cl) and potassium lead chloride (KCl.2PbCl2) are completely or partially dissolved and transformed to residual anglesite (PbSO4), cotunnite (PbCl2) and laurionite (Pb(OH)Cl). At pH 5-6, anglesite is still the principal residual product, whereas at pH > 6, phosgenite (PbCl2.PbCO3) became the dominant secondary phase. The results are consistent with the mineralogical and geochemical studies focused on acidic forest soils highly polluted by smelter emissions, where anglesite, as a unique Pb-bearing phase, has been detected. From the technological point of view, the mixing of APC residue with alkaline water, followed by an increase in the suspension pH and equilibration with atmospheric CO2, may be used to ensure the precipitation of less soluble Pb carbonates, which are more easily recycled in the Pb recovery process in the metallurgical plant.

Air Pollutants↗
PubMed2002

In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.

Apatites↗
PubMed2001

[Use of powder metallurgy for development of implants of Co-Cr-Mo alloy powder].

This paper discusses the application of powder metallurgy for the development of porous implantation materials. Powders obtained from Co-Cr-Mo alloy with different carbon content by water spraying and grinding, have been investigated. Cold pressing and rotary re-pressing methods were used for compressing the powder. It was found that the sintered materials obtained from water spraying have the most advantageous properties.

Humans↗
PubMed1991

Toxicology and occupational hazards of new materials and processes in metal surface treatment, powder metallurgy, technical ceramics, and fiber-reinforced plastics.

Many new materials and processes are about to find their way from the research laboratory into industry. The present paper describes some of these processes and provides an overview of possible occupational hazards and a list of chemicals used or produced in the processes. The technological areas that are considered are metal surface treatment (ion implantation, physical and chemical vapor deposition, plasma spraying), powder metallurgy, advanced technical ceramics, and fiber-reinforced plastics.

Air Pollutants, Occupational↗
PubMedDate not supplied

[Effects of a complex of environmental pollutants in the mining and metallurgy industry areas on the offspring of F1 white rats].

The effects of a complex of ambient air pollutants in the mining- and metallurgy-industry areas on the development of the generation F1 were studied in the experiments on albino rats. The complex of adverse chemical agents of the ambient air was found to exert a pronounced embryotoxic effects on the postnatal development of the generation F1, as manifested by a reduction in the measures of viability, lower size, impairments in the status and physiological development of the central nervous system, in the mechanism of formation of conditioned reflexes, and by the predominance of excitement over inhibition.

Age Factors↗
PubMed1992

[The incidence of paraprofessional diseases in employees of the Research Institute of Ferrous Metallurgy in Kremikovtsi].

The health status of 200 workers from the Institute for Ferrous Metallurgy is studied in view of the harmful effect of the unfavourable factors of the working environment (noise, microclimate, toxic aerosols, gases and vapours). Internal examinations are also performed. A number of laboratory indices are determined in order to assess the liver and kidney functions. A complete blood test and lipid metabolism are examined. Lead and manganese are determined in blood by atomic-absorption spectrophotometry. In 23.5% of the examined are established data for arterial hypertension; with diseases of the gastric-intestinal tract are 22%. The influence of the toxic aerosols and the nervous and psychic loading of the examined workers on the higher prevalence of the paraoccupational diseases are discussed.

Academies and Institutes↗
PubMedDate not supplied

[Vitamin status of workers in steel-smelting departments of the Karaganda Metallurgy Plant].

The author investigated the vitamin status of workers engaged in steel-smelting at the Karaganda Metallurgy Plant. It was found that the workers of the main occupational groups at the plant were insufficiently provided with vitamins A, C and B due to their low content in the food. The system of medico-prophylactic vitamin administration used for steel workers is ineffective.

Avitaminosis↗
PubMed2005

[Possible health effects associated with Pre-Columbian metallurgy].

In the Old World, several researchers have indicated that adverse health effects were associated with exposure to arsenic, and that this influenced a change in the use of copper-arsenic alloys to others less toxic. This hypothesis was evaluated for three Pre-Columbian metallurgy traditions: Central Andes, Intermediate Area, and West Mexico. The metal artifacts from the Central Andes showed arsenic concentrations similar to those in the Old World (0.5%-1.0%). In the Intermediate Area the values were smallest; however, in West Mexico the arsenic content was very high (7%-25%). In Central Andes arsenical bronze was used initially, but copper-tin alloys when introduced were preferred and distributed throughout the Inca Empire. Osteological and artistic evidences of foot amputations among Moche individuals from Central Andes support the presence of "black foot disease" (a condition associated with arsenic poisoning) among Pre-Columbian populations. In conclusion, the adverse effects of arsenic have been observed in the New World, and that these effects promoted a change toward the use of less toxic alloys.

Alloys↗
PubMed1986

[Auditory-vestibular changes in workers in ferrous metallurgy manufacture].

The deleterious factors of the working environment in metallurgy--physical and chemical, with a direct or indirect effect on the analyzer systems of organism could lead to some disturbances of their functions and restriction of the capacity for work of the workers. Seventy workers from coke-chemical production and 98 workers from ferro alloy production have been examined with a view to determination of the auditory and vestibular status among them. The exposure to manganese aerosols has been determined among the workers from ferro alloy production. The indices studied with various degree of exposure have been juxtaposed. Essential changes have been established in the auditory and vestibular analyzer of the workers from both productions. The vestibular disorders have a phase character. The central disorders in the otoneurological state of the workers from coke-chemical production predominate whereas the peripheral ones--among the workers from ferro alloy production. The presence of pronounced changes in the hearing and vestibular indices in the workers with the lowest degree of exposure, provided grounds to propose them as criteria for the early diagnostics of the chronic manganese intoxication.

Adult↗
PubMed1983

[Spirometric studies in clinically healthy metallurgy workers. II. Reference values of basic respiratory indicators].

In a group of 520 clinically healthy men employed in metallurgy, predicted values in the function of age, height and body weight were set up by multiple regression for VC, FEV1 RV, ERV, FRC, RV%TLC and for FEV1%VC in the function of age and for TLC in the function of height. In the tables are given predicted values for VC, FEV1, RV%TLC (based on equations of regression) for 9 intervals of age, height and body weight.

Adult↗
PubMed2005

Contrasting lead speciation in forest and tilled soils heavily polluted by lead metallurgy.

The concentration trends and chemical fractionation of Pb was studied in eight tilled and forest soil profiles heavily polluted by Pb metallurgy in the Pribram district, Czech Republic. The highest Pb concentrations were observed in surface and subsurface horizons attaining 35,300 mg kg-1 in forest soils and 1233 mg kg-1 in tilled soils. Total Pb concentrations were one order of magnitude lower in tilled soil due to intensive ploughing and annual crop off-take. The results of the Tessier sequential extraction procedure showed the preferential binding of Pb in forest soils to operationally-defined exchangeable positions and soil organic matter (oxidisable fraction). The Pb exchangeable fraction is thought to correspond to weak electrostatic binding on the functional groups of organic matter. In tilled soil, Pb is predominantly bound to operationally-defined Fe and Mn oxides (reducible fraction). A comparison with the background Pb concentration values showed a strong contamination even in mineral horizons IIC and confirmed a strong vertical mobility of Pb within the soil profiles. The calculated mobility factors (MF) showed that up to 72% of Pb is mobile and bioavailable in forest soils. In contrast, the bioavailability of Pb in tilled soils was significantly lower as the MF accounted for up to 30%. In the most polluted horizon of forest soil profile, the X-ray powder diffraction (XRPD) analysis confirmed the presence of anglesite (PbSO4), derived likely from the smelter emissions.

Agriculture↗
PubMedDate not supplied

Device for preparing combinatorial libraries in powder metallurgy.

This paper describes a powder-metering, -mixing, and -dispensing mechanism that can be used as a method for producing large numbers of samples for metallurgical evaluation or electrical or mechanical testing from multicomponent metal and cermet powder systems. It is designed to make use of the same commercial powders that are used in powder metallurgy and, therefore, to produce samples that are faithful to the microstructure of finished products. The particle assemblies produced by the device could be consolidated by die pressing, isostatic pressing, laser sintering, or direct melting. The powder metering valve provides both on/off and flow rate control of dry powders in open capillaries using acoustic vibration. The valve is simple and involves no relative movement, avoiding seizure with fine powders. An orchestra of such valves can be arranged on a building platform to prepare multicomponent combinatorial libraries. As with many combinatorial devices, identification and evaluation of sources of mixing error as a function of sample size is mandatory. Such an analysis is presented.

Journal Article↗
PubMed2003

Intensive pre-Incan metallurgy recorded by lake sediments from the Bolivian Andes.

The history of pre-Columbian metallurgy in South America is incomplete because looting of metal artifacts has been pervasive. Here, we reconstruct a millennium of metallurgical activity in southern Bolivia using the stratigraphy of metals associated with smelting (Pb, Sb, Bi, Ag, Sn) from lake sediments deposited near the major silver deposit of Cerro Rico de Potosí. Pronounced metal enrichment events coincide with the terminal stages of Tiwanaku culture (1000 to 1200 A.D.) and Inca through early Colonial times (1400 to 1650 A.D.). The earliest of these events suggests that Cerro Rico ores were actively smelted at a large scale in the Late Intermediate Period, providing evidence for a major pre-Incan silver industry.

Journal Article↗
PubMed2000

[Study on physical properties of titanium alloy sample fabricated with vacuum-sintered powder metallurgy].

OBJECTIVE: To investigate the physical properties of titanium alloy fabricated with vacuum-sintered powder metallurgy. METHODS: The titanium powders of three different particle sizes(-160mesh, -200 - +300mesh, -300mesh) were selected, and mixed with copper and aluminum powder in different proportions. Two other groups were made up of titanium powder(-200 - +300mesh) plated with copper and tin. The build-up and, condensation method and a double-direction press with a metal mold were used. The green compacts were sintered at 1000 degrees C for 15 minutes in a vacuum furnace at 0.025 Pa. In the double-direction press, the specimens were compacted at the pressure of 100 MPa, 200 MPa and 300 MPa respectively. Then the linear shrinkage ratio and the opening porosity of the sintered compacts were evaluated respectively. RESULTS: 1. The linear shrinkage ratio of specimens decreased with the increased compacted pressure(P < 0.05). There was no significant difference among the linear shrinkage ratios of three different titanium powders at the same compacted pressure(P > 0.05), but that of titanium powder plated with copper and tin was higher than those of other specimens without plating(P < 0.05). 2. The opening porosity of specimens decreased with the increased compacted pressure(P < 0.05). Three different sized particle of titanium powder did not affect the opening porosity at the same compacted pressure(P > 0.05). CONCLUSION: The composition of titanium-based metal powder mixtures and the compacted pressures affect the physical properties of sintered compacts. Titanium powder plated with copper and tin is compacted and sintered easily, and the physical properties of sintered compacts are greatly improved.

Dental Alloys↗