【国外标准】 Standard Practice for Determination of Total and Available Cyanide in Solid Waste and Soil after Alkaline Extraction

5.1 Cyanide and hydrogen cyanide are highly toxic. Regulations have been established requiring the measurement of cyanide in soil and solid waste samples. This practice is also useful for performing material balances to account for the distribution of cyanides in cyanidation products from metallurgical processes.5.2 This practice is applicable to the determination of available or total water soluble, or both, and water insoluble cyanides in soil and solid waste.5.3 Water insoluble cyanide complexes, such as Prussian blue, are not completely recovered by distillation methods. This practice extracts all cyanides, including the water insoluble cyanides such as Prussian blue, and then the extract solution can be analyzed for cyanide with Test Methods D6888, D7284, or D7511.1.1 This practice is used for the determination of total or available cyanide in solid waste, sediment and soil samples after alkaline extraction. Simple cyanide (CN-) salts of group 1 and group 2 (alkali and alkaline earth) metals; soluble alkali and alkaline earth salts of zinc, copper, cadmium, mercury, nickel, silver, and iron cyanide complexes; and insoluble metal-metal cyanide complexes, such as Prussian blue, are quantitatively recovered. Gold, platinum group metals and cobalt cyanide complexes are not recovered during analysis.1.2 Free cyanide cannot be determined due to the change of equilibrium conditions during the extraction process.1.3 Cyanide complexes are extracted into an alkaline solution as described in this practice. Measure the total cyanide using Test Methods D7511 or D7284. Measure the available cyanide using Test Method D6888. Calculate cyanide content in the soil or waste.1.4 The method detection limit (MDL) is dependent on the test method used to measure the cyanide content. Based on the methods cited, it is approximately 1 mg/kg and the minimum level (ML) is 5 mg/kg. The applicable range is also dependent on the test method used to measure cyanide. Based on the methods cited, it is 5 to 100 mg/kg.1.5 This practice should be used by analysts experienced with extractions and flow injection analysis (FIA), or working under the close supervision of such qualified persons.1.6 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 This practice offers a set of instructions for performing one or more specific operations. This document cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title means only that the document has been approved through the ASTM consensus process.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 9.1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.