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Humic substances (HS) can be isolated in preparative quantities from low rank coal, peat, and soil. Traditionally, treatment with solutions of NaOH, KOH, or metal salts ([K.sub.4][P.sub.2][O.sub.7]) has been used for their isolation. The aim of this article is to study the effectiveness of different technologies in extracting HS from peat as well as the impact of the different extractive technologies on the properties of the isolated HS. Yields of HS depend very much on the extraction process (extractant, temperature, pretreatment procedures, solvent, mixing intensity); however, the properties of the substances obtained (molecular mass, number of functional groups, spectral characteristics) differ significantly. Yields of HS can be associated with the degree of destruction of the peat fibres and intensive destruction technologies provide opportunities to obtain HS from peat in higher yields than traditional extraction methods. However, during the extraction process, significant degradation of the humic molecules takes place. Key words: extraction, humic substances, peat, properties. Les substances humiques peuvent etre isolees en quantites suffisantes pour les essais a partir de charbon de rang bas, de tourbe et de sol. Habituellement, pour les isoler, elles sont traitees au moyen de solutions de NaOH, KOH ou de sels metalliques ([K.sub.4][P.sub.2][O.sub.7]). Le but de cet article est d'etudier l'efficacite de differentes technologies pour l'extraction de substances humiques de la tourbe ainsi que leur impact sur les proprietes des substances humiques isolees. Les quantites obtenues de substances humiques dependent beaucoup du procede d'extraction (agent d'extraction, temperature, procedures de pretraitement, solvant, intensite de mixage); toutefois, les proprietes des substances obtenues (masse moleculaire, nombre de groupes fonctionnels, caracteristiques spectrales) different de maniere importante. Les quantites obtenues de substances humiques peuvent etre associees au niveau de destruction des fibres de tourbes; les technologies de destruction intensive fournissent des occasions d'obtenir de plus grandes quantites de substances humiques de la tourbe que les methods d'extraction conventionnelles. Les molecules humiques sont toutefois degradees de maniere significative durant le processus d'extraction. Mots-cles: extraction, substances humiques, tourbe, proprietes. [Traduit par la Redaction], Introduction Humic substances (HS) are a general category of naturally occurring, biogenic, heterogeneous organic substances that can be characterized as being yellow to black in color, of high molecular weight, [...]