The Research On The Behavior And Mechanism Of Ultrafine Hematite In The Flocculation-Flotation

The influencing factors of different granularity hematite and the flocculation-flotation test are researched to determine the appropriate size. The flocculation performance of different starch on hematite is investigated. The flocculation-flotation test is carried out by using waxy corn starch. The mechanism between reagents and hematite are studied by various measuring methods.The research to determine the optimum size of flocculation indicates that the size effect is significantly enhanced and the recovery is reduced dramatically when the average size of mineral particle is less than 35?m. Therefore, it is necessary to gather fine hematite particles to be flocs with 35?m effective grain size. The low collision probability of fine mineral particles is one of the important reasons of the poor floatability.The results of flocculation experiments show that the effect of waxy corn starch is better. The 35?m flocs can be get under waxy corn starch 120mg/L, p H=6, the shear stress 3.534 Pa conditions. The flocculation-flotation test was carried under the condition of 20% pulp concentration, p H=6, depressant CMC 20mg/L, activator Y 40mg/L and collector YSB 200mg/L. The grade of concentrate is 59.30% and the recovery is 80.73%.The order of the flocs fractal dimension is waxy maize starch>potato acetate starch>oxidation starch>hydroxypropyl tapioca starch in the same conditions. The stirring speed increases the shear force. There is a negative correlation between the fractal dimension and the size diameter of flocs under different stirring speed. Microscopic observation shows that fine hematite particles adhered together to form flocs with a larger average size, and each of them is independent.The results of Zeta potential and infrared spectrum measurement indicate that four kinds of starch all make the isoelectric point decrease and the maximum adsorption occurs in the p H range of 5~7. Waxy corn starch makes the electric point decrease dramatically and has a strong chemical adsorption in hematite surface, in addition to the existence of hydrogen bonds. Adding activator Y can enhance the adsorption of collector YSB on hematite and effectively improve the flocculation-flotation effect. At the same time, the dosage of collector YSB is also reduced.