Experimental Study on Bacterial Leaching of Low-Grade Phosphate Gangue

The leaching of phosphate ore with sulfuric acid produced by the oxidation of reductive sulfur with Thiobacillus is expected to provide a new way for the comprehensive utilization of low-grade phosphate gangue and protection of environment.However,the rate of phosphate leached from the ore with Thiobacillus is low.Different types of Tween surfactants were used to promote the interaction between the bacteria and the ore.The effects were evaluated by the variation of pH and rate of phosphate leached.The influence of the type and dosage of the Tween surfactants on the growth of Acidithiobacillus thiooxidans and the rate of phosphate leached was analyzed.The experimental results indicated that when adding Tween surfactants of different types with different dosages,the variation trends of Acidithiobacillus thiooxidans density in solution,solution pH,and rate of phosphate leached correspond to each other quite well.The molecular structure and dosage of Tween surfactants are important factors influencing the effects of phosphate ore leaching with Acidithiobacillus thiooxidans.Through selecting the type and adjusting the dosage of Tween surfactants,the growth and acid-producing ability of Acidithiobacillus thiooxidans can be improved.Tween surfactants can improve the leaching of phosphate ore with Acidithiobacillus thiooxidans.Optimal phosphate leaching effects can be obtained by properly selecting the type and adjusting the dosage of Tween surfactants.