The National Institute of Standards and Technology (NIST) recently released the second renewal of its Trace Elements in Coal Fly Ash Standard Reference Material (SRM 1633b). This new material is currently certified for 23 major, minor and trace elements, and concentrations of an additional 24 elements are provided for information only purposes. Current plans are to certify the concentrations of a number of rare earths upon completion of additional analytical work now in progress. Instrumental neutron activation analysis (INAA) has played a major role in the certification of this new material in view of its potential for accuracy, multielemental capability, ability to assess homogeneity, high sensitivity for many elements, and essentially blank-free nature. For an element to be certified in a NIST SRM its concentration is usually determined by at least two independent analytical techniques. INAA has provided analytical information for 15 of the 23 elements certified, as well as for 22 of the 24 elements listed for information only. In addition, INAA has provided much of the homogeneity information for this SRM. This paper will describe these analytical procedures, and highlight those designed to optimize and assess the accuracy of the INAA measurements.
. Biodeterioration of composite based on coal flyash, in CEST 2009,
Proceedings of the 11th International Conference on Environmental Science and Technology
, 3–5 September 2009, Chania, Crete, Greece. Chania: University of the Aegean, 2009. pp. b214–b221
Mineral admixtures such as silica fume (SF), ground granulated blast furnace slag (GBFS) and flyash (FA) are commonly used in concrete because they may reduce the porosity and hence increase the durability and
treating the appropriate raw materials [ 10 – 26 ].
Using the aforementioned procedure, we obtained belite cements (referred to as flyash belite cement (FABC)), in which flyash from coal combustion (class F [ 11 – 14 ] or class C [ 15 – 26 ]) was
sources such as flyash, furnace slag or metakaolin with alkaline liquids (sodium hydroxide and/or sodium silicate) and curing at a moderate temperature.
Geopolymer properties can be tailored by varying the Si:Al ratio, and Davidovits [ 1 ] noted
In this work, the pozzolanic and hydraulic properties of ashes originating from various sources were studied in model systems
such as ash and ash-lime pastes. The sources of studied ashes were: fluidized combustion of brown coal, pulverized combustion
of brown coal and pulverized combustion of hard coal. This article is a continuation of our previously published studies on
cement pastes with mentioned ashes.
The following experimental techniques were applied: calorimetry, thermal analysis (TG, DTG) and infrared absorption (IR).
Previously drawn conclusions relating to the reactivity of ashes in an environment containing Ca2+ ions were confirmed. According to these conclusions, an ash originating from fluidized combustion of coal exhibited higher
reactivity compared to other ashes from pulverized combustion. Pozzolanic and hydraulic properties of this ash were also confirmed.
Differences in the behaviour of ashes originating from pulverized combustion of various types of coal in the presence of water
and Ca2+ rich environment were demonstrated.