Conditions in Bioleaching of Copper Powder from Printed Circuit Board Scraps by Acidithiobacillus ferrooxidans

Four conditions were examined,based on the changes of addition of Fe2+ and Acidithiobacillus ferrooxidans and adjusting of pH value.The aim of this work was to study their influences on the leaching of copper from PCB powder.The result showed that at the PCB powder concentration of 24 g/L in the medium,the leaching rate of copper was the fastest under the condition 1,it reached 100% after 5 d.There was Acidithiobacillus ferrooxidans in the medium under the condition 1.And under the condition 4,the copper was actually leached by acid and its leaching rate was the slowest,it only reached 24% after 5 d.And under the conditions 2 and 3,the leaching rates were 71% and 45%.The outcomes of leaching experiments under different conditions indicated that ferrous ion,acid and Acidithiobacillus ferrooxidans were the three main factors influencing the copper leaching process.