Use of waste pyrite as an alternative to gypsum for alkaline soil amelioration

Abstract

The reclamation of alkaline soils is of great interest especially in arid and semi-arid climatic regions of the world. The aim of this study was to investigate the application of pyrite from the waste materials of a copper concentration plant as an alternative to gypsum application for alkaline soil amelioration. The second aim was to assess heavy metal contamination. Waste pyrite (FeS₂) obtained from a copper concentration plant and pure gypsum (CaSO₄·2H₂O) were added to soil within the columns and pots. Column-leaching tests were performed to determine the effectiveness of waste pyrite application on alkaline soil characteristics as compared with gypsum application. Greenhouse pot experiments were also conducted for evaluating the effects of these soil additives on plant growth. The results indicated that the pH and exchangeable sodium percentage of the experimental soil significantly decreased (p < 0.01) upon waste pyrite and gypsum applications. While waste pyrite was very effective in increasing the levels of essential plant micro-nutrients and dry matter weight of wheat, it did not cause pollution or toxicological problems in the soil. The results of this study clearly indicated that waste pyrite is a good ameliorating agent and an alternative to gypsum in reclamation of alkaline soils.

Keywords:

• waste pyrite
• pyrite oxidation
• alkaline soil
• column test
• greenhouse pot test