Improvement of Alkali soil at China by desulfurization gypsum

Research Project , Research Report 2003

Masayoshi SADAKATA Dept. of Chemical Engineering, the Univ. of Tokyo
Yuji SAKAI Bird Eye Environmental Engineering laboratry, the University of Tokyo
Shohei SHITARA Dept. of Chemical Engineering, the Univ. of Tokyo(Research Partners)
Xu Xuchang Dept. of Thermal Engineering, Tsinghua Univ., Beijing, China

Abstract

Alkali soil reclamation by desulfurization gypsum has been investigated in China in order to solve the air pollution and soil desertification at the same time. The effectiveness of wet and semidry desulfurization gypsum for alkali soil amendments could be confirmed. However, the soil reclamation mechanism was not examined in detail. In this research, salt transport, soil chemical properties (soil pH, electrical conductivity (EC), ion concentration etc.), and soil physical properties (hydraulic conductivity, aggregate, pore etc.) are examined through the soil column experiment adding by Ca(OH)2 or CaSO4. As a result, EC measured in the column had a good correlation with EC, pH, and ion concentration in the discharged soil water. Form this relations, we conjectured reclamation mechanism. It was confirmed that Ca(OH)2 hastened aggregates and increased hydraulic conductivity compared to CaSO4. By the addition of Ca compounds, pores which didn’t exist in alkali soil, were observed on the SEM images.

Keywords:

China, Air Pollution, Desertification, Alkali Soil, Soil Amendment