Evaluation of physicochemical parameters of charcoal residues generated in charcoal kilns

Objective: To characterize the coal waste generated in the coal mines of the UMA La Solución Somos Todos, located in the Nicolás Bravo Ejido, 2nd Section, Paraíso, Tabasco, Mexico. Design/Methodology/Approach: Physicochemical parameters such as moisture content, organic matter, pH, electrical conductivity (EC), phosphorus (P), potassium (K), sulfur (S), and heavy metals were analyzed using standardized techniques on coal waste samples from four coal mines. Moisture and organic matter content were determined by gravimetric methods, while pH and EC were measured using potentiometry and conductimetry, respectively. Phosphorus and potassium concentrations were quantified using UV-Vis and atomic emission spectrophotometry, while lead (Pb), cadmium (Cd), and zinc (Zn) levels were analyzed using atomic absorption spectroscopy. Statistical analyses were also performed. Results: A moisture content of 5.8% and organic matter content of 35%. The pH ranged between 6.5 and 8.3, and EC had an average value of 1.2 dS/m, which is considered acceptable. Phosphorus and potassium concentrations were 28 ppm and 95 ppm, respectively. Sulfur content reached 0.8%, which could pose a risk of acidification. Lead and cadmium levels were recorded at 15 ppm and 2 ppm, respectively. Findings/Conclusions: Coal residues exhibit properties that position them as potential resources for the enrichment of degraded soils due to their high organic matter content and essential nutrients. However, their use is limited by the presence of heavy metals, necessitating pre-treatment before reuse.