A novel method for using residues from the cashew culture is presented. This work aimed to produce and characterize the incineration ashes of the primary residue derived from the cashew's juice extraction, the peduncle bagasse. Measurements showed that these ashes represent only 3% of the incinerated material. EDX analysis indicated the presence of the following elements: C, O, P, K, Mg, S, Na, Al and Si. X-ray diffraction and thermal analyses pointed KHCO3 (54.17%), K2SO4 (34.08%) and MgKPO4 center dot 6H(2)O (10.06%) as the most significant crystalline phases. These results indicate a possible use of this material as an imperishable source of potassium, sulfur, phosphor and magnesium in fertilizers and animal ration. Moreover, it may have many applications since its most abundant component is potassium bicarbonate, compound with several uses. (c) 2006 Elsevier Ltd. All rights reserved.