Abstract: A method produces calcium fulvate from naturally-occurring humus material, such as leonardite, or humic shales. The humus material containing solid fulvic acid and solid humic acid is mixed with water and sodium hydroxide for a first selected period of time to form a solution having a pH of approximately 10.0 thereby solubilizing the fulvic acid and the humic acid. The pH of the solution is reduced to approximately 4.5 and is maintained at the approximately pH 4.5 for second selected period of time thereby precipitating the humic acid as a solid while the fulvic acid remains in solution. The fulvic acid solution is separated from the solid humic acid. The pH of the fulvic acid solution is increased to approximately 13 with calcium hydroxide thereby precipitating the solubilized fulvic acid as calcium fulvate.

Abstract: A method produces magnesium fulvate from naturally-occurring humus material, such as leonardite, or humic shales. The humus material containing solid fulvic acid and solid humic acid is mixed with water and sodium hydroxide for a first selected period of time to form a solution having a pH of approximately 10.0 thereby solubilizing the fulvic acid and the humic acid. The pH of the solution is reduced to approximately 4.5 and is maintained at the approximately pH 4.5 for second selected period of time thereby precipitating the humic acid as a solid while the fulvic acid remains in solution. The fulvic acid solution is separated from the solid humic acid. The pH of the fulvic acid solution is increased to approximately 13 with magnesium hydroxide thereby precipitating the solubilized fulvic acid as magnesium fulvate.