LIANG Bing，ZHENG Ze*，JIANG Liguo

（School of Mechanics and Engineering，Liaoning Technical University，Fuxin 123000，China）

Abstract: Impacts of pH on the phosphorus leaching behavior of phosphate waste rock and the buffer capacity in phosphate waste rock samples were studied by using EPA 1314 Pre-test titration test and acid digestion. Results show that the alkaline buffer capacity is larger than acid neutralizing capacity. It takes 0.1 mmol/g NaOH of 1.0 N to increase pH from 8.75 to 13.50 while it takes 2.2 mmol/g H2SO4 of 1.0 N to reduce pH from 5.50 to 1.00. The pH of leaching reagent is an important factor affectingleachability of phosphate waste rock. The phosphorus leaching is greatly promoted under acidic conditions and the total phosphorus concentration increases with increasingH+ concentration. On the contrary, OH- blocks the leaching of phosphorus, consumes orthophosphoric ions and hydroxyl phosphate ions to generate precipitation and provides more applications for the curing of phosphorus.

Key words: environmental engineering; pH-dependence text; release

EARTH AND ENVIRONMENT Vol. 43, No.3, Tot No.305, 2015, Page 363-368