Enriching and separating iron impurity from Sn-3% Fe melt by super gravity

Iron is one of the major impurity elements in industrially produced crude tin, and it is always removed first during the refining process. In this study, the super gravity field was introduced in the crude tin refining process in order to investigate the directional enriching and separating laws of iron impurity from Sn-3% Fe melt, and thereby purify the crude tin. The experimental results showed that with the gravity coefficient G=500 at a cooling rate of ν=10℃·min^-1, all of the iron-rich phase gathered at the bottom area of the sample; it was hard to find any iron-rich phase particles at the upper area of the sample since super gravity greatly increased the sedimentation of the iron-rich phase in the crude tin melt. The mass percentage of iron in the tailing tin was up to 4.817%, while that in the refined tin was only 0.036%. Consequently, the removal rate of iron was up to 98.78%. The iron-rich phase impurity could be separated effectively from the Sn-3% Fe melt using filtration method in the super gravity field, and the recovery rate of the refined tin increased with increase in gravity coefficient in the range of G > 30. After filtration at 240℃ by gravity coefficient G=100 for 1 min, the refined tin was separated to the bottom of the crucible, and the iron-rich dross was intercepted by the carbon fiber felt. The mass percentage of iron in the refined tin was only 0.253%, while that in the iron-rich dross reached 11.528%. As a result, the removal rate of iron was up to 91.44%, while the recovery rate of the refined tin was as high as 82.69%.