Method for the preparation of low molecular weight alkali metal huminates

摘要

The invention relates to a synthetic preparation of alkali metal salts of low molecular weight humic acids wherein multi-valent phenols are oxidized in a weakly alkaline aqueous medium at a temperature in the range of 15 DEG to 40 DEG C. Subsequently, the reaction mixture is adjusted to a pH value ranging between 6.2 and 7.2 and/or buffered. The low molecular alkali metal huminate is then purified through purification means including preparatory chromotography, ultra-filtration, ultra-centrifugation, or electrodialysis and separated from undesirable by-products.