Smelters antimony

If antimony and arsenic are present ia the feed, copper and iron react to form the respective antimonides and arsenides known as speiss (specific gravity 6.0). If it is preferred to remove copper ia a speiss layer, the sulfur ia the siater must be reduced and the addition of scrap iron may be necessary to encourage speiss formation. Matte and speiss are usually sent to a copper smelter for recovery of the metals. 

AHoy scrap containing tin is handled by secondary smelters as part of their production of primary metals and alloys lead refineries accept solder, tin drosses, babbitt, and type metal. This type of scrap is remelted, impurities such as iron, copper, antimony, and zinc are removed, and the scrap is returned to the market as binary or ternary alloy. The dross obtained by cleaning up the scrap metal is returned to the primary refining process. 

Zinc smelters use x-ray fluorescence spectrometry to analyze for zinc and many other metals in concentrates, calcines, residues, and trace elements precipitated from solution, such as arsenic, antimony, selenium, tellurium, and tin. X-ray analysis is also used for quaUtative and semiquantitative analysis. Electrolytic smelters rely heavily on AAS and polarography for solutions, residues, and environmental samples. 

Total smelter output in the United States has been growing steadily since 1982 because of the growth in antimony oxide production. Primary antimony metal output has decreased since the 1970s because of the falling demand for antimony metal, and the availabihty of low cost metal from China. 

The final ceU product contains 250—300 g/L H2SO in the last stages of electrolyte purification, and antimony and bismuth precipitate, resulting in heavily contaminated cathodes that are recycled through the smelter. Arsenic and hydrogen evolved at the cathodes at these later stages react to form arsine, and hoods must be provided to collect the toxic gas. 

Primary copper processing results in air emissions, process wastes, and other solid-phase wastes. Particulate matter and sulfur dioxide are the principal air contaminants emitted by primary copper smelters. Copper and iron oxides are the primary constituents of the particulate matter, but other oxides, such as arsenic, antimony, cadmium, lead, mercury, and zinc, may also be present, with metallic sulfates and sulfuric acid mist. Single-stage electrostatic precipitators are widely used in the primary copper industry to control these particulate emissions. Sulfur oxides contained in the off-gases are collected, filtered, and made into sulfuric acid. 

As mentioned above, approximately 7% of the total sulfur present in lead ore is emitted as S02. The remainder is captured by the blast furnace slag. The blast furnace slag is composed primarily of iron and silicon oxides, as well as aluminum and calcium oxides. Other metals may also be present in smaller amounts, including antimony, arsenic, beryllium, cadmium, chromium, cobalt, copper, lead, manganese, mercury, molybdenum, silver, and zinc. This blast furnace slag is either recycled back into the process or disposed of in piles on site. About 50 to 60% of the recovery furnace output is slag and residual lead, which are both returned to the blast furnace. The remainder of this dross furnace output is sold to copper smelters for recovery of the copper and other precious metals. 

The information available regarding the association of occupational exposure to lead with increased cancer risk is generally limited in its usefulness because the actual compound(s) of lead, the route(s) of exposure, and level(s) of lead to which the workers were exposed were often not reported. Furthermore, potential for exposure to other chemicals including arsenic, cadmium, and antimony occurred, particularly in lead smelters, and smoking was a possible confounder (Cooper 1976 IARC 1987). These studies, therefore, are not sufficient to determine the carcinogenicity of lead in humans, and the following discussion is restricted to the most comprehensive of these studies. 

A mortality study of 1014 men employed between 1937 and 1971 in a Texas antimony smelter found increased mortality from lung cancer (standardized mortality ratio 1.39) and a positive trend in mortality with increasing duration of exposure. The data also suggested some increased mortality from nonmalignant respiratory heart disease in these workers. 

There are many examples of relatively straightforward use of ICP-MS for the analysis of biological fluids. Antimony has been measured in blood after a 14 1 dilution [236]. Cesium serum levels were found to be elevated in patients with alcohol dementia but not in Alzheimer s disease patients [237]. Cobalt levels in rat serum depended on the form of cobalt [238] ingested. Bismuth levels were measured in human blood and urine by using a direct injection nebulizer [239]. Lead was measured in the blood and blood plasma of smelter workers and the general population [240]. The measurement of trace elements in serum by ICP-MS has been compared to results from neutron activation analysis and proton-induced x-ray emission [241]. Semiquantitative analysis can also be used to obtain a rapid screening of samples [242]. 

The association of the ores of copper with those of other metals is probably the cause of the production of alloys of varying composition by the prehistoric smelters. The earliest copper tools of Britain contain tin those of Hungary up to 4-5 per cent, of antimony.4... 

More complex antimony ores can be treated by leaching with alkali hydroxide or sulfide and by electrolysis of the resulting solution of sodium thioantimonate, Na3SbS4. Elemental antimony can also be recovered from the flue dust of lead smelters. 

Electric Furnace Baghouse Dust, BOF Dust, OH Dust, Coke Fines, Raw Materials, Iron Ore Pelletizing Baghouse Dust, Mold Sand Fines Silicon, Ferrosilicon, Ferromanganese, Ferrochrome Concentrates, Smelter Dust, Precipitates Concentrates, Sinter Mix, Flue Dust, Drosses Tungsten, Molybdenum, Antimony, Brass, Tin,... 

Antimony content of ores for export plus antimony content of antimonial lead and other smelter products produced. 

Kubota and coworkers also analyzed soils and sediments from bismuth-polluted sites at which a bismuth smelter had been operated since 1970. Twenty-four soils at sites within 2 km from the smelter were analyzed. Geometric mean, maximum and minimum values of bismuth and antimony concentrations in the soils were 4.2,122 and 0.45, and 3.2, 37.3 and 0.61 ngg in the dry base, respectively. The bismuth and antimony levels from sediments of the exhaust port and downstream of the river were 200-700 and 100-200 times higher than natural concentrations, respectively Effects of the pollution on the ecosystem were not considered. 

The problem facing all smelters is that there is a continuous occurrence of antimony in their lead streams, at a time when there is a rapidly declining demand for the element. Declining sales of the alloy, which coincide with increasing use of soft-lead-based alloys, will result in antimony effectively becoming a major contaminant that requires removal. Whilst it is relatively easy for secondary reflners to remove antimony from the bullion, the antimony-rich residue from the process may have to be stockpiled. The residue, which contains around 80 to 90wt.% lead, effectively ties up lead units and can have a major cost impact on the reflnery. 

Antimony oxides are released into the environment from smelters, coal-fired power plants and volcanoes (Zoller 1984). Lantzy and Mackenzie (1979) estimated that 3.8x 10 g per year were released globally into the environment from anthropogenic activities. Another important source is vehicle emissions (Dietl etal. 1996). Antimony is transported in the atmosphere over long distances - for instance, from Central Europe to Norway - and accumulates there in soils, plants, mosses, etc. (Steinnes 1997). About 4 tons of antimony are deposited on the Arctic from northern Europe annually... 

Viral transformation of Syrian hamster embryo cells has also been found to be facilitated by trivalent antimony compounds (Fowler and Goering 1991). In workers at antimony smelters, an orange-red to yellowish brown discoloration of the tooth surface ( antimony teeth ) has been observed (Bencze 1994). In 1989, attention was drawn to the possible role of antimony in the sudden infant death syndrome (SIDS) (Richardson 1990). Here, it was postulated that antimony, which was present as a fire retardant in polyvinyl cot mattresses, might be converted by certain molds into tri-... 

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