Production of Humic And Fulvic Acid From Low Grade Coals By Catalytic Oxidation Method With High Purity, High Extraction Efficiency

Abstract

It has been investigated that humic acid and fulvic acid, which have been used rapidly in recent years, are obtained from low quality coals by oxidative method with the help of phase transfer catalysis. The coal sample was oxidized at 60°C with sulfuric acid, nitric acid and hydrogen peroxide in the presence of catalyst. Impurities such as calcium and magnesium were removed with hydrogen fluoride. From oxidized coal samples, humic and fulvic acids were extracted with sodium hydroxide in high purity and high yieldResults: High humic acid extraction rate was obtained in low quality coals using Tetraethylenepentamine as catalyst. Oxidation at low temperature in the presence of catalyst increased the oxidation capacity and oxidation stability of hydrogen peroxide, thus maintaining the biological activity of humic acid and fulvic acid. Hydrogen fluoride was added to the crude humic acid solution and ions such as calcium or magnesium, which could pass into the humic acid solution, were removed by forming compounds such as CaF2 and MgF2. Thus, the purity of humic acid obtained was increased. The solid precipitate obtained at the end of the study may contain a high proportion of humic acid and fulvic acid. The solid precipitate can be mixed with N, P, K and trace elements to obtain organic fertilizers. Thus, all coal raw materials used in the study can be used.