柠檬酸对锡石浮选行为的影响及其作用机理分析

The effect and mechanism of citric acid on the floatability of cassiterite

通过浮选试验考察了柠檬酸对水杨羟肟酸体系中锡石浮选行为的影响,并结合接触角检测、动电位检测和溶液化学计算分析了其作用机理。在7<pH<9范围内,以200mg/L水杨羟肟酸为捕收剂浮选,锡石回收率达到80%以上。在pH>4时,柠檬酸会对锡石产生明显的抑制作用;柠檬酸用量50mg/L、pH=7条件下,锡石回收率仅为25.3%。锡石表面接触角为33°,加入水杨羟肟酸后锡石接触角升高至120°,柠檬酸的作用又使接触角下降至44°。动电位检测和溶液化学计算表明水杨羟肟酸和柠檬酸均可以化学吸附在锡石表面。柠檬酸一方面增强了锡石表面的亲水性,另一方面减少了水杨羟肟酸在锡石表面的吸附,这两方面的作用使锡石在浮选过程中受到抑制。

The influence and mechanism of citric acid to the flotation of cassiterite were investigated by flotation tests,contact angle measurements,zeta potential determination and solution chemistry calculations.The results of flotation experiments revealed that the recovery of cassiterite was above 80% in the pH value range of 7-9 with 200 mg/L salicylhydroxamic acid as the collector.In the range of pH〉4,citric acid showed significant inhibiting effect in the flotation of cassiterite.When pH=7.0 and 50 mg/L citric acid was added,the recovery of cassiterite was just 25.3%.Contact angle measurements demonstrated that the contact angle of the pure cassiterite surfaces was 33°.After the addition of salicylhydroxamic acid,the contact angle was increased to 120°,and citric acid reduced the contact angle to 44°.Zeta potential determination and solution chemistry calculations suggested that both salicylhydroxamic acid and citric acid chemisorbed on cassiterite surfaces.The adsorption of citric acid made the cassiterite surfaces more hydrophilic and decreased the adsorption amount of salicylhydroxamic acid on cassiteritesurfaces,which resulted in that cassiterite was depressed in the flotation process.