铜渣熔融氧化氯化过程中硫的行为特征

Sulfur Behavior Characteristics in the Process of Copper Slags Smelting Chlorination

铜渣进行熔融氧化氯化处理可较好脱除渣中硫,有利于后续工艺渣中铁的回收。通过热力学计算,结合X射线衍射、电感耦合等离子体分析,对铜渣熔融氧化氯化工艺中硫的行为特征进行了研究。结果表明:一定范围内,提高保温温度、延长保温时间和增大氧气流量有利于铜渣脱硫效率的增高,但保温温度高于1 673 K时,脱硫产物SO2与O2及熔渣中CaO作用生成CaSO4留于渣中,使渣含硫上升;氧气流量增至0.5 L/min,SO2和O2反应面与熔渣表面趋于重合,并于熔渣中CaO反应生成CaSO4膜,降低了SO2的扩散脱除速率,不利于渣中硫的脱除。保温温度1 573 K,保温时间25 min,氧气流量0.4 L/min,CaCl2添加量为0.10(CaCl2与铜渣质量比)工艺条件下,处理后铜渣含硫由0.52%降至0.00 511%,氯化法可实现渣中硫的有效脱除。

Sulfur could be removed effectively in the process of copper slags smelting chlorination, which is beneficial to the recovery of iron from copper slags. With the help of the thermodynamic calculation, X-ray diffraction analysis and inductively coupled plasma analy- sis, the sulfur behavior characteristic in the process of copper slags smelting chlorination was studied. In a certain range, the sulfur re- moval rate from copper slags was improved with the increase of the holding temperature, residence time and 02 velocity. However, SO2 was oxidized by the pumped O： and then reacted with CaO forming CaSO4 when the holding temperature was 1 723 K,which caused the sulfur content increase. When 02 velocity was increased to 0.5 L/min, the reaction interface of SO2 and 02 nearly coincided with the molten slag surface, and then the CaSO4 mode was formed through the reaction of S02, O2 and CaO. It caused the sulfur removal rate be- ing decreased. The sulfur content of the copper slag was decreased from 0.52% to 0. 005 11% treated in the condition of holding tem- perature of 1 573 K, residence time of 25 minutes, O2 velocity of O. 4 L/min, and CaC12 addition amounts of 0.1 （ the mass ratio of CaC12 and copper slags）. Sulfur can be removed in the chlorination of copper slags.