Extraction and determination of total and soluble oxalate in pulping and papermaking raw materials

Abstract

Oxalate exists in plant tissue in the form of soluble and insoluble salts. Determination of the oxalate content in a raw material is important for controlling oxalate scaling during the pulping and papermaking processes. In this study, oxalate extraction and determination of the total and soluble oxalate contents in several pulping and papermaking raw materials were investigated. It was found that soluble oxalate can be extracted completely by distilled water at 70 °C within 180 min. Total oxalate can be extracted completely by 2-mol/L hydrochloric acid at 70 °C within 210 min.