2006 年 12 巻 3 号 p. 177-180
The leaching rate of chrome from chromite in sulphuric acid was studied by means of an E-pH diagram of the Cr-Fe-H2O system. The results showed that the leaching rate of chrome changed with the grain size, the concentration and quantity of sulphuric acid and the leaching temperature. The optimum condition for leaching was confirmed as follows: the grain size of chromite sample was 0.074mm, the concentration of sulphuric acid was 75% and the addition of sulphuric acid was 2.5 times of the sample by weight when the temperature and the time of leaching were set at 140°C and 4h, respectively. The leaching rate of chrome was more than 93%.