Leaching tests, cadmium

In a study (Boyle, et al., 1981) conducted by the American Foundrymen s Society (AFS) in conjunction with the University of Wisconsin and the USEPA, leaching tests were conducted on cupola emission control dusts and sludges from 21 different foundries. This study concluded that 9 out of the 21 foundries generated emission control residuals which would be considered as a hazardous waste on the basis of EP Toxicity for lead. Two other foundries generated emission control residuals which would be classified as hazardous on the basis of EP Toxicity for cadmium. Concentrations in the EP Toxicity Test for the 21 foundries ranged from less than 0.6 mg/1 to 130 mg/1. The mean lead... 

Trace metal concentrations (such as lead, cadmium, zinc, copper) foimd in sludge ash are typically higher than concentrations found in natmal fillers or aggregate. This has resulted in some reluctance to use this material however, recent investigations (leaching tests) suggest that these trace metal concentrations are not excessive and do not pose any measurable leaching problem. [179-191]. 

European Union The Council of the European Communities issued directives limiting cadmium levels in ceramics in 1984. Directive 84/500/EEC recognized that cadmium can leach from cadmium glazes or decorations used for ceramic vessels and cookware, and specified maximum allowable extractable levels dependent on the article flat or non-fillable articles, 0.07 mg per square decimeters (dm ) finable articles, 0.3 mg per liter (L) and cookware with a capacity larger than 3 L, 0.1 mg/L (CoEC 2007). This directive specified tests to be conducted for determining the level of cadmium migration from ceramic articles, using 4 % acetic acid as the food simulant. 

The Clean Air Act of 1990 has made trace metal content in fuels and wastes the final ash-related compositional characteristic of significance. Considerable attention is paid (ca 1993) to emissions of such metals as arsenic, cadmium, chromium, lead, mercury, silver, and zinc. The concentration of these metals in both grate ash and flyash is of significance as a result of federal and state requirements of particular importance is the mobility of metals. This mobility, and the consequent toxicity of the ash product, is determined by the Toxic Characteristic Leaching Procedure (tclp) test. Tables 8—10 present trace metal contents for wood wastes and agricultural wastes, municipal waste, and refuse-derived fuel, respectively. In Table 8, the specific concentration of various components in the RDF governs the expected average concentration of trace metals. 

In ceramics, unlike many industries, AAS has not been greatly used, partly because of chemical and other matrix problems, and partly because XRF appeared on the scene shortly after AAS came into use. Its main application in the ceramic industry has been in the determination of metal release from ceramic ware. This is a class of tests designed to establish the likelihood of lead or cadmium leaching from ceramic ware and involves a 24 h extraction at 22°C with 4% (v/v) acetic acid and subsequent determination of lead and cadmium by flame AAS. Current legislation in the USA is driving limits to a level where atom trap AAS, ICP, or graphite furnace AAS is needed. 

In the USA, cadmium pigments must conform to TCLP (toxic characteristic leaching procedure) test limits to meet requirements for non-hazardous wastes. 

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