Study On The Impact Of Flocculants In Backwater On Bauxite Flotation

Abstract:Polyacrylamide (PAM) is commonly used as flocculants to accelerate the settling of bauxite flotation tailings. When PAM returns to the flotation process with backwater, it will have an adverse impact on bauxite flotation. This dissertation has conducted a detailed study on theimpact of PAM on bauxite flotation and its mechanism through different kinds of testing technology, combined with theoretical analysis and flotation experiments. The main contents and innovations as followings:The impact of PAM on bauxite flotation was investigated:PAM will depress the flotation of diaspore and kaolinite and reduce their separation efficiency. Single mineral flotation tests indicate that when the concentration of PAM increases to a certain value, it will reduce the flotability of diaspore and kaolinite. From production data and practical mineral flotation tests we know that backwater will decrease the recovery of A12O3and mass ratio of Al2O3to SiO2.The influence mechanism of PAM on bauxite flotation was studied: the adsorption of PAM on the surfaces of diaspore and kaolinite will hinder the reactions of collectors on mineral’s surface.In addition,PAM has strong flocculation effect on diaspore and kaolinite which is not selective enough. From Zeta potential tests we know that both PAM and NaOL could decrease the Zeta potential of minerals, which means that the adsorption of PAM will increase the electrostatic repulsion of NaOL’s reactions and is bad for the reaction of NaOL. Turbidity tests and laser particle size analysis show that PAM has strong flocculation effect on both diaspore and kaolinite.Aiming at the mechanism of PAM reactions, the dissertation puts forward three solutions to reduce the impact of PAM on bauxite flotation. The first solution is to strengthen the collecting of valuable mineral.The increase of collectors’dosage could improve the recovery of valuable mineral. The second solution is to destruct the flocculation of PAM on diaspore and kaolinitie. The adding of SHMP and approximate strengthening of stirring effectcould make mineral particles flocculated by PAM scattered again.The third solution is to decrease the concentration of PAM in backwater. Results of flotation are improved after decreasing the ratio of backwater.This dissertation includes38graphs and17tables and72references.