Thick-Target PIXE Analysis of Trace Elements in Wood Incoming to a Pulp Mill

Abstract

Trunk-wood samples of wood raw material incoming to a pulp mill were analysed by thick-target particle induced X-ray emission (PIXE). The tree species studied were pine and spruce from Finland, birch from Finland and Poland and eucalyptus from Uruguay. The wood samples were dry ashed to 550°C prior to the analysis in order to increase the sensitivity of the method. The method was calibrated and validated using some wood based certified reference materials. The elements determined with the method were P, S, K, Ca, Ti, Mn, Fe, Ni, Cu, Zn, Pb, Sr, Rb, Ba and F. The concentrations of the main elements P, S, K, Ca and Mn exceeded 50 ppm in most wood samples. The concentrations of heavy metal ions like Cu, Ni and Pb in the samples studied were below or close to 1 ppm. The ash content of birch, pine and spruce wood were in the range 0.2-0.4% and that of eucalyptus ca 0.5%.

Copper in Biomass Fuels and Its Effect on Combustion Processes

“…The approximate concentration level of copper in softwoods and hardwoods (excluding carbon, hydrogen, nitrogen and oxygen) is in the range of 1-10 ppm [15]. Average concentration of Cu in the inner and outer bark of birch, spruce and pine is 2 ppm, higher content in the outer surfaces [16].…”

“…The content of Cu in different biomass varies significantly; for example, Wheat Straw contains 0.06 ppm Cu [17], Beech Wood contains 43 ppm Cu [17], Phyto Remed from plants in contaminated site contains 70 ppm Cu [18], sewage sludge contains 330 ppm Cu [19], Chicken Litter contains 71 ppm Cu [20], and paper sludge contains 310-450 ppm Cu [21,22]. According to Saarela et al [16], the pine bark obtained nearby metal industry in Kokkola, Finland, contained about 515 ppm of Cu.…”

Metal Ion Sorption to Birch and Spruce Wood

“…The ash content in wood is a measure of the inorganic components. For spruce and birch wood from Finland, the ash content is in the range of 0.3 to 0.4% (Saarela 2009). The concentrations of main metal ions in wood such as Ca, Mg, and K are in the range of 100 to 1000 ppm (Ivaska and Harju 1999;Saarela 2009).…”

Energy Dispersive X-ray Fluorescence Analysis of Sulfur in Biomass

“…Metal ions can be analyzed by a number of quite sensitive instrumental methods and can be removed from solutions by ion exchange or other selective methods. With few exceptions, , the sulfur content in biomass has not been studied at the low level required for most feedstocks.…”