Leaching of low grade zinc oxide ores in nitrilotriacetic acid solutions

• A novel and efficient leaching agent was proposed to treat the low grade zinc oxide ores.
• The high zinc extraction and low iron extraction was obtained by controlling a suitable nitrilotriacetic acid concentration.
• The leaching agent was regenerated by adjusting the pH of the leaching solution.

A new method for the selective extraction of zinc from low grade zinc oxide ore in nitrilotriacetic acid solutions was proposed. A thermodynamic study indicated that the leaching process could be made efficient and selective by controlling the pH of the leaching solution. When low grade zinc oxide ore samples were leached in a 0.25 M nitrilotriacetic acid solution at 40 °C for 2 h with a liquid–solid ratio of 10 mL/g, the leaching ratios of zinc and iron were 91.0% and 4.1%, respectively. Additionally, the nitrilotriacetic acid was regenerated by adjusting the pH of the leaching solution after the leaching process.