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The humic acid (HA) is an organic fraction that can be found in soil and watercourses as well as in carbonaceous matrices. In recent years the interest associated with this substance has been growing steadily as new applications are discovered, such as fertilizers, remediation of degraded areas and treatment of wastewater contaminated with metals. The main features of HA are dependent on the method of extraction and the chosen matrix, since it can be extract from a wide range of raw materials, as well as by different methods. Within this context, the main objective of this work is related to an assessment of the potential of extracting humic acid from different carbonaceous precursors. three different carbonaceous matrices were used: coal tailings (RCM), coke (CM) and green petroleum coke (CVP). Besides this experimental study some results of a similar study available in the literature were presented. The extraction method used was adapted from Trompowski et al, and the characterization was done using ICP- OES techniques, CNHS, MEV / EDS and FTIR. The extraction efficiency, in terms of mass recovery, significantly varied depending on the method used, the best results being associated with coal tailings (17.0 percent), while lower efficiency relates to the calcinated petrocoke after distillation (0.2 percent). The extraction from green petroleum coke, as received, is unfeasible due to its immiscibility with the nitric acid solution. The results obtained from FTIR were satisfactory for all the HA analyzed, displaying bands consistent with those from HA and compatible with bands shown in the literature. The results of the analysis of ICP-OES showed a low presence of metals and trace elements coming from the HA for coke. With respect to the extracted humic acid from coal tailings, which showed the highest initial concentration of metals, particularly iron, was successfully implemented, a purification with nitric acid. Based on the results obtained it can be stated that the use of different carbonaceous precursors allowed the extraction of humic acid with similar characteristics as cited in the literature and those obtained from other sources.