Development of a European standard for the determination of acid potential and neutralisation potential of sulfidic waste

摘要

European Directive (2006/21/EC) on the management of waste from the extractive industriesrequires guidance on waste characterization as a basis for the development of wastemanagement plans. CEN, the European standardization organization, has commenced workon standards for extractive waste. One of the work tasks is to develop tools for determinationof "acid generation behavior". Test methods for the determination of acid generation behavior can be divided in static andkinetic tests. A static test is usually relatively fast to perform, but gives only indicativeinformation based on total composition of the waste material. The kinetic test gives moredetailed information on behavior based on reaction rates under specified conditions. This paper describes a European static method draft developed for waste characterization ofsulfide bearing materials which may generate sulfuric acid when subjected to weathering. Inthe test draft specified methods for determining both the acid potential (AP) and theneutralization potential (NP) of the material are presented. Here the focus is more on thedetermination of NP. From these results the net neutralization potential (NNP) and theneutralization potential ratio (NPR) are calculated. Basis for the standardization work were the existing static test methods applied in theextractive industry and research. Background for the choice of the method to be standardizedis discussed in the paper.