| The effect of gravity by shaking table, magnetic separation and flotation were compared, and the gravity by shaking table method was chosen as the first segment due to its good performance. The mechanisms and influencing factors of the roast process were investigated. The results showed that the primary phosphatic mineral in the iron ore is svanbergite, and that when roasted above 500℃svanbergite will decompose gradually and transform into aluminum phosphates, which can be dissolved in acid. This shows that dephosphorization can be greatly improved by roasting followed by leaching. When roasting temperature reaches 1025℃, the resultant will turn into cubic aluminum phosphates, which is less dissolvable in acid. The experiment showed that best roast temperature is 800℃. The correlative mechanisms and influencing factors of the leach process were also investigated, and the results showed that when leaching time is less than 1 hour, leach process was controlled by chemical reaction, and when leaching time is more than 1 hour, the leaching process was controlled by internal diffusion. The increase of acid concentration and leaching temperature can enhance the leaching efficiency of phosphorus at the initial stage of reaction. The leaching efficiency of phosphorus is in proportional to the square root of time in the internal diffusion controlled stage. |
