Effects of the extractants on the characteristics of a humic fertilizer obtained from lignite

✍ Scribed by D. Garcia; J. Cegarra; M. Abad; F. Fornes

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 464 KB
• Volume: 43
• Category: Article
• ISSN: 0960-8524
• DOI: 10.1016/0960-8524(93)90034-9

✦ Synopsis

A humic fertilizer containing humic and fulvic acids was extracted from lignite. The effects of the extractants on the yield of extraction and on the characteristics of humic acids were investigated.

The following extractants were used: ~1, 0"25, 0"5 and 1"0 M KOH and ~1 M NaOH. Acid pretreatments were performed with 0"1 M HCl prior to the extraction with either 0"1 M NaOH or 0"1 M KOH. Also, 0"1 M HN03 was used prior to the extraction with 0"25 M K OH.

Acid pretreatment of lignite increased the yield obtained after further extraction with 0,1 M KOH, but the largest yield was achieved when 0"5 M KOH was employed. Humic acids released by 0"25 M KOH following the 0"1 M HNO 3 treatment exhibited higher H: C and O : C ratios, greater contents of functional groups and higher molecular size than humic acids obtained without the acid pretreatment. Iron content of the humic fertilizer was increased by acid pretreatments of lignite, the extent of such an effect depending on the type and concentration of the acid employed.