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Trace and minor elements like arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), thin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) are important in cement clinker manufacturing. Even in low concentrations these elements influence the production processes, the quality of the products and the environment. The environmental issues are the volatility of elements at high temperatures to the atmosphere and the leachability of elements from concrete products to the surroundings. If a prediction tool was available of the fate of elements to the gas phase and to the cement clinker phases several advantages could be achieved. Therefore a calculation tool is developed based on thermodynamic equilibrium calculations with a two-step method. Most of the thermodynamic data are taken from the FactSage^TM database 6.4 and the solutions phases are adjusted for cement clinker and similar applications.

The tool estimates the volatility of the elements at a temperature below onset of melt formation during production and after formation of melt. The results from the simulations are volatility of each element at low and high temperature and if the element is non-volatile it concentrates in the condensed phases.

In this article four sets of full scale industrial data from a cement clinker and a lime production plant are used to evaluate the prediction tool. The results comprise an inventory of the extent of thermodynamic data for selected trace and minor elements, thermodynamic calculations with distribution to gas or condensed phases with input from full scale measurements, the influence of oxidizing, less oxidizing and slight reducing conditions on the behavior of elements, results from full scale industrial measurements and a comparison between the calculated and the measured distribution of elements. For the cement clinker production eleven elements and for the lime production twelve elements are considered.