Research On The Effect Of Cationic Reagent Structure On The Performance Of Mixed Anionic/Cationic Collectors For Spodumene Flotation

Flotation is the important process and used frequently for the separation of spodumene from gangue minerals,and the screening or development of high-efficiency collector for spodumene flotation is the key and difficult point.Anionic and cationic combined collector flotation method has shown good collection and selectivity,which is a research hotspot at present.In order to further study the effect of collector structure on the flotation performance of spodumene and select the better anionic and cationic combined collector,this paper had discussed the effect of cationic collector structure on the performance of anionic and cationic combined collector for spodumene flotation.Through the flotation experiments of single mineral and artificial mixed ore,we systematically studied the influence of the structure and ratio of cationic collector and found out some new anionic and cationic combined collectors with better flotation performance.By means of quantum chemistry calculation,adsorption capacity test and reagent solution performance analysis,the influence mechanism of cationic reagent structure on the flotation performance of the anionic and cationic combined collector is discussed further.The main conclusions are as follows:（1）The single mineral flotation experiments show that the difference of cationic collector structure or radio leads to different flotation performance of anionic and cationic combined collector for spodumene.The solid-affinitive capability of amino group is stronger than that of amide group,and the two amino groups located at both ends of carbon chain shows better selectivity than that located in the middle of carbon chain for spodumene flotation.For cationic collector structure,adding anionic groups can improve the collection ability and selectivity of the combined collectors for spodumene flotation;increasing the number of amino group or methyl group（on amino N atom）will improve the collection ability of combined collector for spodumene,but their selectivity will also decrease.In addition,within a certain chain length range,the carbon chain of cationic agent is directly proportional to the collection capacity of its combined collector for spodumene,feldspar and quartz.With the increasing proportion of cationic reagents,the collection capacity of combined collectors of amide agents for spodumene decreases;The collection capacity of combined collectors of amphoteric agents for spodumene increased first and then decreased;The collection capacity of combined collectors of alkyl amines and diamines for spodumene both increased,but the selectivity decreased.In the alkaline p H range,the increase of DDA proportion is conducive to the collection of spodumene and feldspar;The increase of N,N-dimethyl-dodecylamine or 1231 ratio is conducive to the collection of spodumene and quartz;The increase of the proportion of 1,12-diaminododecane is conducive to the collection of feldspar and quartz.Besides,after washing with 3%HCl solution,the floatability of spodumene shows a significant decrease.But the flotation performance of spodumene after pickling can be improved by adjusting the structure or ratio of cationic reagent in the anionic and cationic combined collector.Adding methyl on the N atom of amino group,or adding amino groups at both ends of the carbon chain,or increasing the ratio of cationic reagent can improve the collection ability and selectivity of the combined collector for pickled spodumene.（2）The artificial mixed ore flotation experiments show that the two combined collectors of oleic acid 120 with 1,12-diaminododecane and oleic acid 120 with N,N-bis（2-hydroxyethyl）dodecanamide can effectively flotate natural spodumene from feldspar and quartz.When the ratio of oleic acid 120 to 1,12-diaminododecane is 12:1,the dosage is 100 mg/L,and the p H is about 9.0,the Li₂O recovery and separation efficiency in the concentrate are 91.73%and 71.01%respectively.When the ratio of oleic acid 120 to N,N-bis（2-hydroxyethyl）dodecanamide is 6:1,the dosage is 50mg/L,and the p H is about 8.0,the Li₂O recovery and separation efficiency in the concentrate are 85.55%and 76.24%respectively.In addition,the combined collector of oleic acid 120 with 1,12-diaminododecane still has a certain separation effect on the artificial mixed ore after pickling with 3%HCl solution.（3）The solution performance analysis results of collectors show that increasing the number of amino group（-NH₂）,or adding methyl on the N atom of amino group,or adding new functional groups can improve the surface activity of the combined collector solution,reduce the CMC value,enhance the mutual association between anionic and cationic reagents,enhance the adsorption on the solid-liquid interface and the tightness of arrangement,and improve the collection ability of the combined collector.When the length of carbon chain or proportion of cationic agent is moderately increased,the solution performance of its combined reagent will be enhanced.Furthermore,the higher the ionization degree of active group of cationic reagent,the stronger the collection ability of the combined collector.The results of quantum chemical calculation and adsorption capacity analysis show that 1,12-diaminododecane in the combined collector is easier to adsorb on spodumene（110）surface,which is better than DDA,and it also has a certain adsorption on pickling spodumene.At the same time,with the increase of the chain length or ratio of 1,12-diaminododecane,the adsorption capacity of the combined collector on spodumene increases.The adsorption of oleic acid 120 combined with1,12-diaminododecane or N,N-bis（2-hydroxyethyl）dodecanamide on spodumene is stronger than that of feldspar and quartz,presenting good collection ability and selectivity.