More coal power plants are retiring yearly, and more countries are phasing out these plants in hope for more sustainable future. This will free up large amounts of coals specifically low-rank coals (like lignite and subbituminous) for utilization in non-combustion routes. Therefore, it is of paramount importance that alternative, cost-effective, efficient, and sustainable routes are developed and investigated. In this study, the conversion of lignite to humic acids is investigated. Humic acids are organic fertilizers and soil conditioners that help deliver nutrients to plant, improve soil structure and help retaining water in the soil. Humic acids have a potential market growth of 14% compound annual growth rate (CAGR) over the next decade. The growth is driven by the need for more organic fertilizer and the deterioration of soil health due to climate change. Current commercial technologies for humic acids production suffer from longer extraction time and low yields. Therefore, ultrasonic processing is being introduced in this study as a novel and new technology to improve the yield and reduce the time required for the production of humic acids from lignite. Ultrasonic processing is based on cavitation phenomena where ultrasound goes through the solution to generate microbubbles that grow and eventually collapse causing high localize pressure and temperature. Chemical and physical effects happen during ultrasonic processing leading to higher rates of reactions. During the reaction, oxygen is being incorporated creating more humic substance and the alkaline media allows for higher solubilization in the solution. Several parameters have been investigated including amplitude, reaction time, initial lignite concentration, KOH amount, and the concentration of H2O2. The international standard ISO19822 method was employed for product characterization. Product characterization also includes the use of FTIR, TOC, CHN analysis and TGA. The characterization confirmed the conversion of lignite to humic acids, allowed for the quantification of humic acids and gave a picture of the chemical and physical characteristics of the products. A lump kinetics model based on power law and Arrhenius equation was built to calculate the kinetics triplets, rate constant, activation energy and pre-exponential factor.