Nuclear analytical techniques in the sugar cane agroindustry

Brazil is the world's largest producer of ethanol (13 billion liters per year) and sugar (12 million tons per year) from the milling of 240 million tons of sugar cane. It also has the potential to provide 240,000 tons of dry yeast per year, derived from ethanol production, for use as a protein supplement to animals. Mechanization of field operations has changed the quality of the cane supply due to significant amounts of soil entering the mill. Drawbacks of the soil on factory performance and costs have prompted an investigation to develop a reliable method for assessing its content in the cane supply. Nuclear methods, involving the determination of elements present in much higher concentrations in soil than in cane, such as instrumental neutron activation analysis (Al, Fe, Hf, Sc, Th), energy dispersive X ray fluorescence analysis (Al, Fe, Si, Ti, Zr) and natural gamma-ray emitter radionuclides (Pb-212) were considered. INAA has also been applied in evaluation studies of the efficiency of the cane washing system, wearing rates of industrial machinery and the consequent introduction of metallic elements in the cane flow, elemental dynamics during the fermentation process, and elemental composition of brown and white sugars and yeasts.