Obtaining fulvic acids from leonardite

The objective of the study is to determine the process parameters for obtaining fulvic acids from leonardite (mining is carried out by LLC Stepanovsky Razrez, Kansk-Achinsk basin). Tasks: to determine the rational parameters for extracting fulvic acids from leonardite; to determine the total yield of fulvic acids from leonardite. The yield of fulvic acids was determined according to GOST 9517-94 "Solid Fuel. Methods for Determining the Yield of Humic Acids" with modifications. To extract fulvic acids from leonardite, a 1 % solution of sodium bicarbonate (NaHCO3) was used as an accessible and safe reagent for their further use in the food industry. To separate the fractions into humic and fulvic acids, the resulting alkaline extract with a pH of 9 to 13 was acidified with acid solutions to a pH of 1-2, as a result of which humic acids precipitate, and fulvic acids remain in the solution. Technological parameters for extracting fulvic acids from leonardite deposit located in the Kansk-Achinsk basin of LLC Stepanovsky Razrez have been developed. The development of technological parameters for extracting fulvic acids from leonardite consisted of determining the dependencies of the fulvic acid yield on the liquid module, the duration of the process and the temperature regime. The highest yield of fulvic acids (7.45 %) was observed when using caustic soda as an extractant with a water module of 1:50. While with the same value of the water module, but when using sodium bicarbonate as an extractant, the yield of fulvic acids was slightly lower (7.40 %). When using sodium bicarbonate as an extractant, a rational water module for extracting fulvic acids is a water module of 1:100 with a rational temperature of 60 °C. With an increase in the duration of the extraction process to 3.5 hours, an insignificant increase in the yield of fulvic acids is observed, however, extraction for 2 hours can be recommended for greater economic feasibility.